ALMA Band 1 Receiver Development Study

ALMA Band 1 Consor t ium

ALMA Band 1 Receiver Development Study

A u t h o r s : P . T . - P . H o , Y . - J . H w a n g , P .

K o c h , C . K a m p e r ( A S I A A ) , K . Y e u n g , S .

C l a u d e , J . D i F r a n c e s c o ( N R C - H I A ) , K .

S a i n i , S . S r i k a n t h , M . P o s p i e s z a l s k i

( N R A O ) , N . R e y e s , & L . B r o n f m a n

( U C h )

D a t e : F e b r u a r y 1 0 , 2 0 1 2

Call for Proposals

PROPOSAL FORM

Call for Studies of Upgrades of the Atacama Large Millimeter/submillimeter Array (ALMA)

PRINCIPAL INVESTIGATOR: ……………………………………………………………………….. Institution e-mail Telephone Address

* Note: The Study Agreement shall be concluded between the NAASC and the Bidder/Institute.

Call for Proposals – NAASC Proposal Form page 2/4

1. CO-INVESTIGATOR(S)/ASSOCIATED INSTITUTION(S)

Name/Institution Contact Info - email/Telephone

2. SUBCONTRACTORS The companyʼs authorization to be proposed as subcontractor should be obtained by the

Contractor prior to completion and signature of this Proposal Form. Firms and Addresses: Subcontracted Parts:

Call for Proposals – NAASC Proposal Form page 3/4

3. EFFORT AND COST BREAKDOWN The Bidder shall estimate the effort (in Full Time Equivalent – FTE) to be deployed by Bidder and Associates/Subcontractors (items 4.1 through 4.5) until completion of the Study, as well as the corresponding total costs to be incurred by the Bidder (items 4.6 through 4.9). Also, the Bidder shall indicate the level of financial support expected from ALMA/NA (item 4.10), if any, consistent with item 4 of Annex 1.

Item Description Estimate and breakdown of Effort in FTE

4.1 Science

4.2 Management

4.3 Engineering

4.4 Others

4.5 Total FTE (items 4.1 to 4.4)

Item Description Estimated Cost in USD

4.6 FTE

4.7 Travels

4.8 Other Costs

4.9 Total cost (items 4.6 to 4.8)

4.10 Firm fixed price in USD to be paid by ALMA/NA for the Study


North American ALMA Science Center – Call for Studies of Upgrades of ALMA 1/23

TABLE OF CONTENTS

Table of Contents

1 Science Considerations ..............................................................................................................2 1.1 Star Formation and the Interstellar Medium.........................................................................3

1.1.1 Star formation: Key molecular tracers for the earliest cores .................................................................. 3 1.1.2 Anomalous Emission from Very Small Grains ......................................................................................... 3

1.2 Extragalactic Science............................................................................................................4 1.2.1 S-Z studies of Galaxy Clusters ................................................................................................................. 4 1.2.2 Low-J CO transitions from high-Z Galaxies............................................................................................ 4

1.3 ALMA vs. Jansky VLA........................................................................................................5 2 Technical Description ................................................................................................................5

2.1 Introduction ..........................................................................................................................5 2.2 Receiver Architecture ...........................................................................................................6 2.3 Systems Engineering.............................................................................................................7 2.4 Optics....................................................................................................................................8

2.4.1 Optics Design (NRC-HIA, UCh and NRAO)............................................................................................ 8 2.4.2 Lens (NRC-HIA, UCh and NRAO)........................................................................................................... 8 2.4.3 Feedhorn (UCh, NRC-HIA and NRAO)................................................................................................... 8

2.5 OMT (NRC-HIA, UCh and NRAO) ....................................................................................9 2.6 Cryogenic Low Noise Amplifier (LNA) (NRAO, NRC-HIA and ASIAA).........................9 2.7 Cryogenic Mixer (NRC-HIA and ASIAA) ........................................................................10 2.8 Filter (ASIAA)....................................................................................................................11 2.9 Local Oscillator (NRAO, ASIAA) .....................................................................................11 2.10 Band 1 Cartridge Test Set (UCh) .......................................................................................12

3 Interfaces to ALMA.................................................................................................................12 4 List of Deliverables..................................................................................................................12 5 Project Management ................................................................................................................12

5.1 Functional Structure ...........................................................................................................13 5.2 Schedule..............................................................................................................................13 5.3 Budget.................................................................................................................................14

6 Heritage and Facilities .............................................................................................................14 6.1 ASIAA................................................................................................................................14 6.2 NRC-HIA............................................................................................................................14 6.3 Universidad de Chile ..........................................................................................................15 6.4 NRAO.................................................................................................................................15 6.5 Band 1 Design Study Team Biographies............................................................................16

7 Publications..............................................................................................................................21



INTRODUCTION The ALMA Band 1 Consortium is pleased to submit the proposal to the call for studies of proposed development upgrades of ALMA. The Band 1 Consortium consists of four organizations, the Academia Sinica Institute of Astronomy and Astrophysics of Taiwan (ASIAA), the Herzberg Institute of Astrophysics of the National Research Council of Canada (NRC-HIA), National Radio Astronomy Observatory (NRAO) of the United States of America, and the Departmento de Astronomia, Facultad de CienciasFisicas y Matematicas, Universidad de Chile (UCh). The Band 1 Consortium (called hereafter the “Consortium”) was formed with the objective to collaborate on a reciprocal basis in the development of a prototype Band 1 receiver for the ALMA project.As detailed under the “Technical Description” section below, this collaboration includes continued parallel development, by several of the partners, of different design options. The parallel development effort will culminate in the selection of the optimum design approach based on performance, cost, and ease of maintenance considerations.

Our consortium has carefully examined the science potential of Band 1 receivers. Though previously defined at 31.3-45 GHz, for science reasons we believe that there is significant merit in shifting Band 1 nominally to ~33-50 GHz. This proposed frequency coverage is an ambitious challenge. The goal of the design study is to trade off the receiver architecture against the science requirements and costs. A full suite of Band 1 receivers will both extend and expand ALMA’s science capability, bringing both new and complementary science to the observatory and its user community. Band 1 will allow exciting probes of galaxy clusters, high-redshift galaxies, the interstellar medium (ISM) of our Galaxy and star and planet formation, among other possibilities. The study we propose here will include a thorough examination of the optimal frequency boundaries for Band 1 science. We will also examine the technologies required for the development of Band 1 receivers. We will also determine the feasibility of the conceptual design to meet the current specifications and future science requirements based on the performance of the prototype components of the receiver.

The science-enabling technologies of a Band 1 receiver are: • Low-noise cryogenic amplifiers • Orthomode transducers • Mixers • Optical design.

From a technical and management perspective, the proposed receiver design concept is • Simple • Reliable • Cost effective

Additional features to be considered in this concept design study are the reproducibility and the manufacturability of the design in a production environment.

1 Science Considerations

In this proposal, several key science drivers are highlighted for receivers of ALMA Band 1. In the decade since the ALMA re-scoping exercise, the science case for Band 1 has grown stronger. A meeting on Band 1 science held at NRC-HIA in Victoria, Canada in October of 2008 reaffirmed its broad relevancy. From that meeting, Johnstone et al. [1] produced an expanded Band 1 science case that has been updated twice since its first publication online (http://xxx.lanl.gov/abs/0910.1609). For space reasons, we refer the reader to that document for more detailed discussions of the science drivers we highlight below, as well as many other cases.



1.1 Star Formation and the Interstellar Medium 1.1.1 Star formation: Key molecular tracers for the earliest cores

Stars form out of dense gas pockets within molecular clouds called “cores,” after the cores become gravitationally unstable and collapse. Tracing molecular line emission from cores within our Galaxy gives us direct insight into the dynamics and chemistry associated with star formation. Indeed, the present suite of ALMA Bands will already be used to trace such characteristics, but the higher frequency lines that the present Bands cover will trace warmer or denser material associated with star formation. Of special interest are the characteristics of gas early in the development of cores, i.e., when cores themselves condense out of ambient molecular material. Such locations are now being identified in abundance through continuum observations from the Herschel Space Observatory but little kinematic data exist to characterize their dynamics. Lower-density gas can be traced well in general by lower-frequency lines found in Band 1, as discussed by Johnstone et al.[1], and the presence of many interesting lines in the 45~50 GHz range argues strongly for Band 1 to include frequencies higher than those for which it was initially defined.

At 45~50 GHz, the primary lines for tracing “early core material” come from CS and C34S (i.e., 1-0, at 48.99 GHz and 48.21 GHz respectively). For example, Kaifu et al. [2] used the CS 1-0 line to discover the rotating disk around the archetypical low-mass protostellar objects L1551 IRS 5, while Tatematsu et al. (1993) [3] performed a dense core survey in the Orion A cloud. The ground-state CS line is ideal for studying cold, starless cores prior to the onset of the initial collapse, because the critical density of the CS line (~104 cm-3) matches the typical gas density of starless cores, and the upper-state energy level (~2.4 K) is low enough to be excited in cold (~10 K) starless cores.

Other important lines that trace early core material within this frequency range include those from the “carbon-chain” molecules, e.g., HC5N (17-16 at 45.26 GHz) and HC3N (5-4 at 45.49 GHz). In addition, the 45~50 GHz frequency range also includes the 43-32 line at 45.38 GHz of CCS, another carbon chain molecule that has a relatively large Zeeman splitting factor that enables it to probe directly the strength of the line-of-sight component of magnetic fields associated with early cores. These carbon-chain molecules have lower J transitions in the 31~35 GHz range, which we will lose when shifting the frequency, and hence the net result is no loss of access to these species. Finally, the 45~50 frequency range includes CH3OH (10-00 A+) at 48.37 GHz which traces shocks associated with molecular outflows and “hot” molecular cores associated with higher-mass star formation.

1.1.2 Anomalous Emission from Very Small Grains

Over the last decade, surprisingly bright emission at ~30-40 GHz has been detected toward Galactic objects, including dark clouds [4]. One possible explanation of the anomalous dust emission is electric dipole radiation from rapidly rotating (“spinning") very small dust grains (VSGs), as calculated by Draine Lazarian[5]. Hence, this emission may be a direct probe of an important but little understood component of the interstellar medium (ISM). So far only broad-band measurements of the anomalous emission exist, and the spectral information provided by Band 1 can help confirm or test the spinning dust emission mechanism. Directly measuring the VSG abundance and size distribution constrains the chemical and thermal balance of the ISM and could explain unidentified infrared emission features. Most observations of anomalous emission have been made in low-resolution CMB experiments (where it acts as a foreground component), but higher spatial resolution is needed to characterize it better and to resolve the distinct environments where spinning dust may arise.

Band 1 receivers on ALMA would have the high resolution and sensitivity to both large- and small-scale structures needed to characterize the locations of VSGs, especially in relatively compact locations like circumstellar disks. For example, Rafikov[6] estimated that differences between the spectrum of spinning VSGs and “typical" dust found in disks (i.e., where the dust opacity power law index ~ 1) will be seen in a matter of



minutes with ALMA Band 1, and that grain size distributions may be well constrained with longer observation times. Distinguishing dust sizes is important for a better understanding of disk evolution. For example, planet formation is expected to begin with the growth of dust grains to larger sizes, but significant abundances of VSGs within disks suggest a different scenario where dust grains fragment to smaller sizes in these environments. High resolution is required for Band 1 data because of the possibility of significant contributions of free-free emission at these frequencies, e.g., from bipolar outflows and jets. High-resolution observations at several frequencies, however, would allow such components to be spatially distinguished.

1.2 Extragalactic Science 1.2.1 S-Z studies of Galaxy Clusters

The Sunyaev-Zel'dovich Effect (SZE) is a distortion in the spectrum of the Cosmic Microwave Background (CMB) due to inverse Compton scattering of CMB photons by hot plasma [7, 8]. At Band 1 frequencies, the SZE appears as a decrement in the line-of-sight CMB intensity, with the signal proportional to the product of the electron density and electron temperature (~neTe). Since this quantity is related to the total thermal energy in the plasma, it measures the total mass when virial equilibrium is assumed. Galaxy clusters are both the largest virialized objects and the largest repositories of hot plasma in the universe, so observing the SZE toward galaxy clusters probes their masses and the structure of their intracluster media (ICM).With cluster mass measurements, the SZE also can test cosmological models (e.g., dark energy) since such models can be sensitively constrained by the galaxy cluster mass. For example, the abundance and distribution of total halo masses with redshift is a key prediction of cosmic structure formation models. X-rays can also probe the ICM but this signal is proportional to ne

2Te0.5. Hence, the SZE is much more sensitive to hotter gas, and measures directly local

departures from thermal pressure equilibrium.

Many PI-driven continuum SZE studies of galaxy clusters have been made over the last decade, at low angular resolution (>1' FWHM), and new ~1000 deg2 SZE surveys at similar resolutions are underway with the Atacama Cosmology Telescope (ACT) and South Pole Telescope (SPT).Unresolved structures within the ICM of galaxy clusters are believed to account for much of the scatter seen between cluster masses and SZE observables. This scatter is the limiting factor in making cosmological inferences from the small samples of clusters already published. Merger-driven shock fronts in the ICM, for example, can increase the peak SZE in a cluster by an order of magnitude [9], and high-resolution SZE data sensitively reveal these shocks when they are present (e.g., [10]). They can also shed light on the details of astrophysical mechanisms in the ICM such as electron/ion equilibrium [11], helium sedimentation [12], and AGN-inflated “bubbles” [13]. Band 1 receivers on ALMA will provide the only observational capability to observe efficiently and at high angular resolution the large samples of southern-hemisphere clusters which are being discovered with ACT and SPT, and remove systematic biases inherent in those lower-resolution data. Indeed, the shorter baselines and wider primary beam areas of ALMA (in particular, the ACA) can be used to detect efficiently the diffuse extended SZE, while the longer baselines of ALMA can be used to detect discrete sources that confuse the SZE signal. Neither ALMA Band 3 nor the EVLA (D-array) have sufficient surface brightness sensitivity or FOV to map the virial regions of large samples of SZ clusters at high angular resolution. The lower-resolution ACA Band 1 will be useful for more accurately determining the properties of high-z massive cluster candidates detected, for instance, in the eRosita all-sky x-ray survey. These rare objects provide important tests of Lambda CDM [14].

1.2.2 Low-J CO transitions from high-Z Galaxies

The star formation rate within galaxies peaked at redshifts of Z = 1-2, inviting special scrutiny as a major epoch of galaxy evolution. Since stars form out of clouds of molecular gas, probing such clouds within high-Z galaxies gives insight into the environments where such high star formation rates occurred. These clouds can be probed directly by observing CO lines, and these are redshifted to frequencies 1/(1 + Z) times their respective rest frequencies. Such line signals from galaxies are weak, and in the past typically high-J lines have been



detected toward mostly brighter high-Z submillimeter galaxies. Indeed, ALMA and its current suite of receivers will have the high sensitivity needed to detect redshifted CO and [CII] emission from a wider selection of high-Z galaxies, including more modest star-forming galaxies (e.g., BzK galaxies at z = 1.5-2 [15]) than have been typically probed so far with lower sensitivity instruments.

As higher-J transitions of CO require higher excitation conditions, data of these lines are likely biased towards denser or warmer regions of galaxies. Lower-J transitions, however, could sample larger volumes of molecular material within galaxies, but many of these lines are beyond ALMA's present frequency ranges at the redshifts of interest. Such lower-J CO lines may be indeed brighter than higher-J ones toward more modest star-forming galaxies, given that there may be relatively less dense or warm star-forming gas in these objects. Band 1 receivers on ALMA will detect such redshifted lower-J transitions, neatly complementing detections of CO or [CII] lines in higher frequency Bands and allowing significantly better characterizations of these young galaxies. What redshifts can be observed will depend upon the actual frequency range chosen for Band 1, however. Assuming a 33-50 GHz range, Band 1 receivers could observe CO (1-0) towards galaxies over Z ~ 1.3-2.5 with similar redshift coverage of CO (3-2) or CO (4-3) in Band 4 (a small gap exists at Z ~ 1.8). This covers an important range of active star formation which is difficult to probe optically due to dust obscuration and a lack of strong optical lines. Moreover, the [CII] 2P3/2-2P1/2 line could be observed in Band 9 toward a subset of these galaxies over Z ~ 1.6-2.2. Toward higher-Z galaxies, Band 1 receivers could observe CO (2-1) over Z ~ 3.6-6.0, while CO (4-3) can be observed in Band 3 for Z ~ 3.6-4.5. In addition, [CII] emission can be also observed over Z ~ 3.6-5.6 using Bands 7 or 8 (a small gap exists for Z ~ 4.0). It will also be feasible to carry out large-area blind CO surveys with expected detection rates ~0.4 BzK galaxies per hour and up to 10x this in cluster-lensed fields [16,17]; in fact, most Band 1 observations will serendipitously provide these data.

1.3 ALMA vs. Jansky VLA

The Jansky Very Large Array (VLA), located at a latitude of +34˚ and an altitude of 2124 m, presently has the capability to observe all frequencies at 1-50 GHz. There, Band 1 frequencies are covered by two separate receiver suites, i.e., at Ka-band (26.5-40 GHz) or Q-band (40-50 GHz).With such capability already in place, why build a Band 1 receiver for ALMA? At the low end of the range we consider (35 GHz), EVLA and ALMA will have comparable single-field, center-of-field point source sensitivities (~40 microJansky RMS in 60 seconds), but ALMA will have ~5x faster mapping speed due to its larger primary beam. Moreover, in the middle of the EVLA Q-band, ALMA’s site and surface quality deliver ~1.6x lower noise than EVLA resulting in over 10x higher mapping speed. ALMA also has better short spacings via ACA and the 12 m telescopes, thereby yielding higher image fidelity. In addition, ALMA will observe astronomical targets at southern declinations that are inaccessible to the Jansky VLA. In the design study, we will simulate and quantify the strengths and advantages of ALMA over Jansky VLA, for a range of science projects.

2 TECHNICAL DESCRIPTION

2.1 Introduction

Band 1 will be the lowest signal frequency band of ALMA , and is specified to cover the frequency span of 31-45 GHz. However, to the science case presented in the previous section suggests a range of 33-50 GHz. Information of the Band 1 receiver can be found in the Front End Sub-system technical specifications [18] and in the ALMA system block diagram [19]. As shown in Figure 1 (from [19]), the main components consist of focussing optics, the orthomode transducer for splitting the signal into two orthogonal linear polarizations, cryogenic low noise amplifiers (LNA), downconverting mixers and room temperature amplifiers. The cartridge has two cryogenic stages, 15 K and 110 K. The original architecture as presented in Figure 1 will have to be revisited in light of the proposed frequency band.



Given the fact that the Band 1 Consortium consists of four partners, it is natural to see parallel development for key components and system architecture. A number of publications showing the group’s activities on Band 1 development over the past few years can be found in [22] through [38]. These parallel efforts are intentional as some of the critical components require extra development to meet the Band 1 specifications. At the end of the development phase, a down-selection will occur based on science needs, performance, and ease of manufacturing for the production phase. The following sections describe the status of development of various Band 1 components.

Figure 1: Band 1 Schematic Diagram from [10]. This represents a simpler receiver configuration which can cover the specified ALMA Band 1 frequency range of 31.3 – 45 GHz, by down-converting only the upper side-band.

2.2 Receiver Architecture

Two architectures are proposed for the Band 1 system. The first one shown in Figure 1 follows the original layout except that the LO covers 31-38 GHz. The LNA and mixers are cooled on the 15 K stage for optimum noise. The double side band mixer down-converts the RF signal in the upper side band with an IF of 4-12 GHz. Further amplification of the IF at room temperature is done before interfacing the signal to the back end system.

Figure 2: Top level system block diagram for the proposed ALMA Band-1 receiver, along with the relevant interfaces. Both the cold cartridge and the warm cartridge (incorporating the first local oscillator subsystem) assemblies are shown. Some components can be simplified and combined with others as described in the text, but the most conservative and generalized scheme is depicted here for illustrative purposes.



The second proposed receiver scheme for Band-1covering the extended frequency range, involves down-conversion to IF (4 – 12 GHz) using room temperature mixers installed on the warm IF amplifier plate in the side-band separating. The warm IF amplifier plate will be mounted on the “back side” of the warm cartridge assembly (WCA). Unlike other ALMA bands, which have SIS mixers within the cold cartridge, the output of the Band-1 cold cartridge will be the RF signal at sky frequency, rather than an IF signal. This scheme has been chosen because there will be sufficient RF gain within the cold cartridge to overcome the noise from the subsequent room temperature mixers. The “blind mate” waveguide connections developed for higher bands (for coupling the W-Band LO drive signals) can be scaled and should work well for the RF signal. This also reduces the number of penetrations of the vacuum vessel to only two, since the mixers are located outside the cold cartridge. The outputs of the 2SB processors (two IF outputs per polarization) will then be amplified using 4 – 12 GHz IF amplifiers, similar to the ones in use by other ALMA bands.

While the WCA is easier to maintain without breaking vacuum, careful analysis of the amplitude and phase dependence of the mixers and IF hybrids (in addition to that of warm IF amplifiers) on temperature variations are required in order to ensure that the relevant ALMA specifications are met.

The choice of the 90° IF hybrids and the warm IF amplifier described above is relatively straightforward, since commercially available “custom” units are in use for other ALMA bands (e.g. Band 6 and 9) and already cover the desired frequency range. Commercial mixers (e.g.Spacek MQ-8) are available for use in the proposed frequency range but will need to be packaged appropriately to meet the amplitude and phase stability requirement when used in the thermal environment of the warm IF amplifier plate.

2.3 Systems Engineering

The ALMA FE Specifications document [18] calls for a receiver noise performance of 17 K SSB over 80% of the RF band and 26 K SSB over any RF frequency in the band. The specified noise performance is defined as the noise performance as measured at the cryostat window (and is intended to include contributions from the cryostat window, IR filters as well as any external warm optics if applicable.)

Table 1 shows the preliminary gain and noise budgets for the second receiver configuration proposed above (the first option has very a similar total noise). The two main contributors to the noise budget are the warm optics and the cryogenic LNA. The latter is already the focus of development by all partners of the Consortium (see the section on LNA development), while options to reduce the optics noise are discussed in the optics section. One of the outcomes of this design study shall be a change request to modify the receiver noise specifications along with possible shift of the frequency range to 33-50 GHz, so as to accommodate observation over the additional spectrum of interest as described in Section 1.

Table 1: Preliminary gain and noise calculations for one of the proposed receiver configurations.

Component/Stage Gain (dB)

Noise Figure (dB)

Noise Temperature

(K)

TEQ (K) referenced to

the input Warm optics 10 10 Q-Band Amplifier (cold) 30 15 15 Waveguides and feed-thru -3 298.6 0.3 Q-Band Amplifier (Room Temperature)

15 3 298.6 0.6

RF Hybrid -4 453.6 insignificant Mixer -7 1203.6 0.2 IF Hybrid -4 453.6 0.4 Warm IF Amplifier 30 2 175.5 0.4 Total 57 26.8



2.4 Optics

2.4.1 Optics Design (NRC-HIA, UCh and NRAO)

The optics for Band 1 and 2 are the most demanding bands in terms of size. The optical elements are too large to be accommodated inside the dewar and hence, the original ALMA Front-end Optics design report [20] only included the feed horn inside the dewar. Reflective optics were considered, but were found to be too bulky to fit in the widget space above the cryostat; therefore a lens was used to couple the waist of the horn to that of the telescope, forming a rather compact arrangement which could be accommodated in the space available. A single feed-horn is employed since the polarizations are separated using an orthomode transducer (OMT).

The telescope beam waist is 43.8 mm at 42 GHz and is located at a distance of 280 mm above the cryostat top plate. By proper choice of the feed horn parameters and the focal length of the lens, the horn waist can be matched to the telescope waist at all frequencies within the band. The lens also serves as the vacuum window at 300 K. The lens will contribute about 7 K to the receiver temperature. The infrared (IR) filters at the 15-K and 110-K stages contribute another 1.5-2 K.

2.4.2 Lens (NRC-HIA, UCh and NRAO)

The designed feed horn has a waist of 8.5 mm at 42 GHz and using a lens of focal length 175 mm, results in an output waist of 43.8 mm. The average taper is about -12.7 dB at the edge of the subreflector over the frequency band. The dielectric lens will be machined out of high density polyethylene. Application of antireflection coating, to obtain low reflection coefficient over the 33-50 GHz band, will be explored. NRC-HIA has developed and tested an antireflection design that would be suitable for the lens [23]. Given the high noise contribution of the lens as presented in the noise budget (Table 1), solutions to reduce this noise will be presented. These solutions include the investigation of different lens materials and relocation of the lens to the 15 K stage.

UCh has manufactured a lens for the UCh test set, which is described in Section 2.10. It is planned to investigate ways to improve the bandwidth of the design up to 50 GHz. Also, a method to characterize the lens material has been developed and an improved method with increased accuracy will be tested.

2.4.3 Feedhorn (UCh, NRC-HIA and NRAO)

NRC-HIA has manufactured a prototype feedhorn based on the design of M. Carter [20]. The technique used can readily be transferred for production as it is using a conventional CNC lathe. An alternative method, consisting of electroforming, was not selected due to added risk and costs in the production phase.

UCh has designed and produced a feedhorn based on a corrugated spline profile ([32] and [38]). This design offers a much shorter horn size and is more suited for space limited cartridge layouts. Given the new design, a manufacturability study, in a batch project, will be completed.

Both NRC-HIA and UCh feedhorns will be re-designed for operations up to 50 GHz.

NRAO has designed a wideband feed horn with ring-loaded corrugations in the mode converter. A horn with such a mode converter will have reflection coefficient better than -22 dB.



2.5 OMT (NRC-HIA,UCh and NRAO)

The orthomode transducer for the ALMA Band 1 receiver should have the following features: ease of manufacture and assembly, no requirement for any tuning, repeatable performance, and low cost. The Boifot junction OMT, used in JVLA and ALMA Band 3 and 6 receivers, has pins in the entry into the ports of the side arms and a septum in the main-arm port. This type of OMT has a bandwidth ratio of only 1.47:1. Experience shows that the number of rejections is fairly high and assembly is non-trivial.

NRC-HIA has designed and tested four units, fabricated in an outside workshop, in a real production environment [35]. The first version was a prototype for performance verifications only, not intended for cartridge installation. Performances and reproducibility are excellent within the 31-45 GHz band. A second version, designed to meet the cartridge configuration requirements and operate up to 50 GHz, will be tested in 2012. Depending on the performance achieved, a preliminary version of the production feedhorn will be based on this design.

UCh has designed a dual-ridge orthomode transducer to cover the original Band 1 frequency range (31-45 GHz) [33]. A first prototype was produced and tested in 2011. The measurements show good performance across the band. Moreover, the performance of the unit is still acceptable up to 50 GHz, opening the possibility for broadband operation of the device.

NRAO has developed an OMT based on turnstile junction that possesses two-plane symmetry. This OMT does not have any pins or the septum as is the case with the Boifot junction OMT. It was developed for the JVLA X-band (8-12 GHz) receiver and has a square input waveguide 0.900"x0.900" [40]. A square prism at the base of the square waveguide acts as a tuning element providing excellent input match. The main body of the OMT is composed of three major blocks. The output ports are of split-block construction. The mechanical design ensures easy assembly and requires no tuning. Measurement were made on the X-band OMT between 7.5 and 12.5 GHz. When scaled to Q-band, return loss is ≥ 19 dB from 32 to 52 GHz. Insertion loss is typically about 0.1 dB and crosspolarization coupling is ≥50 dB. This NRAO OMT design will be one of the front contenders for the Band 1 receiver.

2.6 Cryogenic Low Noise Amplifier (LNA) (NRAO, NRC-HIA and ASIAA)

The best reported noise temperatures, at frequencies below 50 GHz, have been demonstrated on amplifiers built using InP HFET devices from the so called “cryo3” wafers produced by the Northrop Grumman Space Technology (NGST) in 1999 for the Jet Propulsion Laboratory Deep Space Network (JPL DSN) under the Cryogenic HEMT Optimization Program (CHOP). These wafers contain tens of thousands of HFET chips with 80 nm gate length and varying device peripheries. Cryo-3 devices have been used in all JVLA amplifiers (about 600 have been built) and their noise and signal models [41] are well understood. A preliminary design of NRAO 33-50 GHz ALMA Band-1 amplifiers using cryo-3 devices has been developed and the expected performance is presented in Figure 3. The credibility of these projected results is further enhanced by comparison with measured results for 38-50 GHz JVLA amplifier (over 100 were built for JVLA).



Figure 3: Expected noise temperature and gain of 33-50 GHz amplifier. This amplifier will have a useful performance over 31-52 GHz frequency range. For comparison the minimum noise temperature of this amplifier is also plotted as well as the measured performance of JVLA Q-band amplifier.

Through the ALMA Band 3 program, NRC-HIA has developed expertise in LNA design and fabrication. The 4-8 GHz cryogenic LNA required for Band 3 was prototyped at NRC-HIA and then 340 production units were manufactured through a license agreement with a Canadian amplifier company. From that experience, the NRC-HIA team developed prototypes of LNAs for Band 1.The first LNA design was based on InP transistors for optimum noise and low power dissipation at the 15 K stage, and on individual components (hybrid design) that were linked by wire bonds. In addition to the circuit designs, the team also focused on the input/output connectors and the mechanical housing that will facilitate automated assembly operations in the production phase. To further improve the reliability of the amplifiers, waveguide-to-microstrip transitions for both the input and output stages are under construction. All these new features will be incorporated into the new LNA prototype that will be ready for testing in the summer of 2012. A 5-stage minimum design is being planned for the next round of development for optimal gain performances.

At ASIAA, a 30-50GHz LNA based on 0.15 μm metamorphic high-electron-mobility transistor (MHEMT) monolithic microwave integrated circuit (MMIC) process was successfully designed and tested. The noise performance is still higher than the specification of the first-stage front-end amplifier, but it is sufficiently good to serve as a gain stage of the front end. For development of the first-stage front-end amplifier, a hybrid-MMIC approach by using the 0.1 μm InP HEMT discrete device and quartz substrate with a 0.1 μm GaAs PHEMT will be designed, fabricated and tested.

2.7 Cryogenic Mixer (NRC-HIA and ASIAA)

At NRC-HIA, a wideband InP dual-FET mixer was designed using hybrid integrated circuitry. The mixer is composed of two InP FETs arranged in cascade configuration with each FET biased separately. The dual-FET mixer achieves 2 dB of conversion gain from 31 GHz to 45 GHz with 22 dB of LO-to-RF isolation, and a return loss of 10dB for the IF and LO ports and 15 dB for the RF port. A prototype will be assembled and tested in 2012. For the pre-production version of the mixer, integration of a waveguide to microstrip transition will be explored. The use of low power InP transistors allow for cryogenic operation.



At ASIAA, a 30-50GHz cascade HEMT mixer module with conversion gain around 0 dB was implemented [30]. The cryogenic testing is currently under progress. Revised design of the mixer based on the same cascade transistor pair will be iterated to gain better RF and IF port matching and optimize the design under a cryogenic environment. ASIAA plans to develop the integrated downconverter module once the amplifier and mixer MMIC chips are both ready. Once it is implemented, it can support both receiver architectures shown in Figures 1 and 2.

2.8 Filter (ASIAA)

The Band 1 system shown in Figure 1 will operate in the upper side band of the double side band mixer. Therefore, a means to filter the lower side band is important. The LNA does not provide a sharp cut off below 31 GHz, therefore a specific filter must be designed. Several 31.3-45 GHz planar high-pass and band-pass filters have been designed and fabricated by ASIAA’s university collaborators using a GaAs MMIC process [35]. In year 2012, more development is planned to provide lower in-band insertion loss and wider pass band for a shift and broadening of Band 1 operating frequencies. The revised version of the filter to cover at least 33-50 GHz is to be developed based on either GaAs MMIC process or quartz-based thin film process.

2.9 Local Oscillator (NRAO, ASIAA)

Unlike SIS receivers, for a HEMT LNA receiver, the mixer noise does not have a significant contribution to the overall receiver noise temperature as the mixer follows the first stage amplifier. Consequently, it is not necessary to optimize the Local Oscillator (LO) power as a function of observing frequency. The allowable LO power range is much greater, so that the LO driver for each polarization will not need to be independently programmable with respect to the output power. A simple power splitter will suffice. Similar to ALMA Band 3, the LO for Band 1 will only have the room-temperature “driver” part and no cryogenic frequency multiplier components that are implemented for the higher bands. The power dissipation and volume considerations justify placing the LO in the Warm Cartridge Assembly (WCA), consisting of the source oscillator, the Active Multiplier Chain (AMC), and the Power Amplifier (PA). The block diagram of the LO system is included in the top level system block diagram of Figure 2, in conjunction with and alongside the signal conversion scheme. Given the low phase noise requirement, the oscillator, spanning the frequency range of 14.5 – 19 GHz, will be a commercially available, broadband electronically tunable fundamental mode YIG tuned oscillator (YTO). Following the YTO will be the two custom blocks, the AMC and the PA. The function of the AMC will be to double the YTO output in frequency, amplify and filter the output, and mix with the millimeter-wave phase reference from the photo-mixer. The mixer IF output is then sent to a PLL module to be compared against the First LO Offset Generator (FLOOG) signal, in order to phase lock the YTO. The PA module will divide the LO signal from the AMC into two channels and amplify them. The amplified LO signals will then be routed to the two mixers of the dual-polarization receivers. Based on the performance of similar LO assemblies of the other ALMA bands, this LO is expected to meet the phase drift specification of 12 fs and phase noise specification of 38 fs. The exact LO frequency coverage will be determined based on the analysis of the importance of and the need to provide coverage for the various spectral lines in the 30 – 52 GHz range and the proposed LO configuration is flexible enough to cover the resulting LO requirements.

As noted above, independent power control may not be needed for each polarization, the “PA” block in the WCA could be replaced with a downconverter block, containing receiver chain mixers, RF post amplifiers and LO amplifiers as needed. The RF output from the cartridge (exiting on the WR-22 waveguide) could be routed to this block, conserving the basic WCA topology used for other ALMA bands.

ASIAA has laboratory prototypes of local oscillator based on the phase-locked Ka-band GaAs HBT MMIC VCO ([24],[29] and [39]) and 14-17GHz YIG oscillator. Further development on improving the GaAs HBT



VCO is in progress, and ASIAA will participate in the development of the local oscillator module based on the experience of the phase-locked YIG oscillator.

2.10 Band 1 Cartridge Test Set (UCh)

A Band 1 prototype receiver will be assembled during 2012 at UCh. It will be tested in the UCh test facilities, which include an ALMA test cryostat designed to test Band 1 cartridges. The UCh cartridge will be a platform for testing components provided by the Consortium to provide system level characterization.

In addition to cryogenic components that will be assembled in the cartridge, the Consortium will benefit from the work of ASIAA on a prototype warm cartridge assembly. A 4-12 GHz IF amplifier based on 0.15 μm MHEMT MMIC process has been successfully tested with 18-27 K cryogenic noise temperature. This amplifier is not only suitable for a future cold IF stage but is also suitable for prototype warm cartridge assembly along with the YIG-based phase-locked oscillator as an LO. A prototype warm cartridge assembly based on the effort indicated above is capable of providing sufficient support for Band 1 system integration and testing. ASIAA will make use of the existing East Asia Front-End Integration Center (FEIC) facilities to develop the future production line cartridge testing configuration.

3 Interfaces to ALMA

Below is the list of the interfaces between Band 1 and the rest of the Front End system. If the RF band is changed, the effect on the interfaces will be studied to guarantee full functionality of Band 1 within ALMA.

ICD, Band 1 Cartridge to Front End Bias module (FEND-40.02.03.00-40.02.03.06-A-ICD.doc)

ICD, Band 1 Cartridge to Front End Cryostat (FEND-40.02.03.00-40.03.01.00-A-ICD_1.doc)

ICD, Band 1 Cartridge to Front End IF Switch (FEND-40.02.03.00-40.08.01.00-A3-ICD.doc)

ICD, Band 1 Cartridge to Band 1 First local oscillator (FEND-40.02.03.00-40.10.03.00-A-ICD.doc)

4 List of Deliverables

Based on requirements identified in the science case study as well as the results of the prototype component evaluation, a set of proposed technical specifications of the Band 1 receiver will be presented at the completion of the design study. The deliverables for this Band 1 design study will be:

• A set of science and functional requirements, including a precise frequency range optimized for science

• A set of realistic and achievable technical requirements

• A report detailing the technical description of the Band 1 receiver and its major subsystem components

• An estimate of the production cost of a suite of seventy-three Band 1 receivers

• An estimated production schedule of seventy-three Band 1 receivers.

5 Project Management

ASIAA will be the lead institute of this design study program. ASIAA will work on project management and systems engineering together with NRC-HIA. Project management methodology at NRC-HIA is based on a combination of tools, including the SAP financial software system customized for the National Research



Council, MS Project and MS Excel software. The SAP system allows real-time tracking of labour and non-labour costs using electronic timesheet entries. Procurement orders are tracked using a centralized requisition module in SAP. Project progress and status will be monitored through bi-weekly team meetings and reported to NRAO through monthly reports. The monthly reports will include a narrative account of the monthly progress status together with details of efforts, expenses and financial commitments tabulated in MS Excel format.

5.1 Functional Structure

ASIAA, NRC-HIA, NRAO, and UCh are members of the Band 1 Consortium. Its objective is to collaborate in fields of astronomy and astronomical instrumentation, particularly for the development of ALMA Band 1 receivers.

Due to the stringent Band 1 noise temperature specification, new technologies must be considered in the receiver design. Parallel development activities among the three partners are intentional to develop new ideas and approaches that will help meeting the technical requirements set forth by ALMA. At the completion of the design phase, a final design will be down-selected for the production phase.

The main areas of developmental activity by each member of the Consortium are shown in Table 2, the functional organization chart of the proposed design study.

Table 2.the functional organization chart of the proposed design study

Item \ Consortium ASIAA HIA NRAO UCh

Optics ○ ○ ○ OMT ○ ○ ○

Cryogenic LNA ○ ○ ○ Filter ○ Mixer ○ ○

LO ○ ○ Cartridge

Mechanical Layout

○ ○ ○

Cartridge Integration ○ ○

Cartridge Test System ○ ○

System Engineering ○ ○ ○

Project Management ○ ○

Production Preparation ○

5.2 Schedule

This is a twelve-month study. Assuming a start date of March 1, 2012, the submission date of the final design report will be March 1, 2013.



5.3 Budget

The estimated budget for the design study is presented in Table 3. ASIAA and UCh have kindly offered to provide in-kind efforts and resources to conduct this design study.

Table 3 – Estimated budget and human resources

Consortium Laboratory Name and Personnel Category

Estimated Cost (US $)

ASIAA Paul Ho (Principal Investigator), Yuh-Jing Hwang, Ciska Kemper, Chau-Ching Chiong, Yue-Fang Kuo, Patrick Koch, Kai-Yang Lin -

NRC-HIA Stephane Claude, Keith Yeung, James Di Francesco, Philip Dindo, Frank Jiang, Doug Henke $555,125

UCh Nicolas Reyes, Leonardo Bronfman, Fausto Patricio Mena, Ricardo Finger -

NRAO John Effland, Brian Mason, Marian Pospieszalski, Kamaljeet Saini, Sivasankaran Srikanth $179,665

Total Cost (US $) $734,780

Cost in excess of the contract award amount will be covered by in-kind contributions from the member institutions.

6 Heritage and Facilities

6.1 ASIAA

As established in October 1993, ASIAA is with fast-growing radio instrumentation projects since 1995. The Microwave Device Laboratory (MDL) of ASIAA, which was officially established in 2009, is the main group in ASIAA conducting the development of ALMA Band 1 receivers. The development of the microwave and millimeter-wave components for astronomical instrumentation in ASIAA actually started in 2000. A series of broadband sub-harmonically pumped diode mixers for W-band were developed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. The MMICs related to ALMA local oscillator and Band1 components were started in 2005. The MDL has six members so far, including one Ph. D. level specialist, two postdoctoral associates, and two junior engineers (one in microwave and one in mechanical). In addition, a broad collaboration network with four professors from the National Taiwan University, National Central University and National Chung-Cheng University on MMIC and passive millimeter-wave circuit design has been established.

6.2 NRC-HIA

The Astronomy Technology Research Group-Victoria at NRC-HIA has a long, distinguished history in the design and construction of state-of-the-art millimeter and sub-millimeter receivers for radio astronomy observatories. Many NRC-HIA systems and sub-system components are in operation at several world-class



radio astronomy observatories, including Receivers A3 and B3 at the James Clerk Maxwell Telescope (JCMT), 100 GHz double-sideband mixers at CARMA, 100 GHz sideband separating mixers at the Arizona Radio Observatory (ARO), and, more recently, the ALMA Band 3 receivers. The group is also active in the research and development of novel low-noise cryogenic amplifiers, highly integrated antenna array receivers, and wide-band single-pixel feed antennae.

6.3 Universidad de Chile

Radio astronomical instrumentation has a long tradition in Universidad de Chile, starting with the construction of Maipú Radio Observatory, first in Latin America (1959). In 2005 the Astronomy Department started a Mm-wave Laboratory, at the National Astronomical Observatory in Cerro Calán, with the upgrade to HEMT technology of a 115 GHz receiver for the 1.2 m Southern Mm-wave Telescope. In 2007, the Radio Astronomy Instrumentation Group was formed, with the Electrical Engineering Department, and a joint PhD program was established. The group was funded in 2008, through the Chilean Center of Astrophysics and Associated Technologies, to develop a prototype receiver for ALMA Band 1, and started work in cryogenic LNAs and receiver optics. The receiver development group is comprised by two professors, five engineers, a professional mechanic, and graduate students, and has strong relations with a concurrent photonics group. Further activities include the AIV of six Band 5 receivers, with a European consortium; a sideband separating mixer for Band 9, with SRON; and construction of a 2SB front-end and digital back-end for the 1.2 m Telescope.

6.4 NRAO

The CDL at NRAO is the world leader in research and development of radio astronomy instrumentation. CDL has designed, developed and fabricated key receiver components for NRAO facilities, eg. Jansky VLA, VLBA, GBT and ALMA (Band 6, Local Oscillator for all bands and LO reference optical distribution). It also has provided designs and/or manufactured components to many other radio astronomy research facilities such as WMAP, LF Planck, Radioastron, CBI, DASI, VSA, AMI and many others.



6.5 Band 1 Design Study Team Biographies

Paul Ho (Principal Investigator)

Education: Ph. D. in Physics, Massachusetts Institute of Technology (1977).

Expertise: Radio Astronomy

Relevant Project: Submillimeter Array (Project Scientist), Yuan-Tseh Lee Array for Microwave Background Anisotropy (Principal Investigator), Atacama Large Millimeter Array (Taiwan Principal Investigator), Greenland Telescope (Principal Investigator).

Yuh-Jing Hwang

Education: Ph. D. in Communication Engineering, M.Sc. and B.Sc. in Electrical Engineering, National Taiwan University (2005, 1993 and 1991).

Expertise: Microwave / millimeter-wave engineering, including microwave monolithic integrated circuits / modules, and heterodyne receivers.

Relevant Project: the Submillimeter Array of Taiwan (Microwave / Receiver Engineer, IF and LO development, first-generation 600-696GHz and 320-420GHz receivers inserts for antenna 7 and 8), Yuan-Tseh Lee Array for Microwave Background Anisotropy (Microwave / Receiver Engineer, prototype and pre-production receiver front-end, W-band SHP diode mixers, and LO-IF system development), Atacama Large Millimeter Array Taiwan Project (co-Investigator, microwave components for band-1 and revised local oscillator development).

Chau-ChingChiong

Education: Ph. D. in Astronomy, University of Bonn, Germany (2003); M.Sc. and B.Sc. degrees, Electrical Engineering, National Taiwan University (1999 and 1997).

Expertise: Microwave and Millimeter IC (MMIC) design for astronomical receiver, including cryogenic low noise amplifier (LNA), wideband voltage-controlled oscillator (VCO) and related phase-locked loop (PLL) system etc.

Relevant Project: The Atacama Large Millimeter Array (ALMA) project.

Yue-Fang Kuo

Education: Ph. D. and M. Sc. in Electrical Engineering, National Dong-Hwa University (2010 and 2005)

Expertise: CMOS radio frequency integrated circuits; millimetre- wave local oscillator module.

Relevant Project: HBT VCO-based local oscillator module for Band 1 of ALMA



Ciska Kemper

Education: Ph.D. in Astronomy, University of Amsterdam (2002); M.Sc. in Astronomy, Leiden University (1997)

Expertise: Astrophysics of dust; life cycle of dust and gas; ISM in galaxies; evolved stars; infrared and submillimeter astronomy

Relevant Project: ALMA-Taiwan (project manager); Spitzer Space Telescope (SAGE-LMC and SAGE-Spec projects)

Kai-Yang Lin

Education: Ph.D. in Physics, National Taiwan University (2006)

Expertise: clusters of galaxies, SZE observations; radio interferometry; system commissioning

Relevant Project: Yuan-Tseh Lee Array for Microwave Background Anisotropy (project scientist)

Patrick Koch

Education: Ph.D. in Physics, University of Zurich (2003); M.Sc. in Physics, ETH Zurich (1999); B.Sc. in Mechanical Engineering, ETH Lausanne (1995)

Expertise: clusters of galaxies, SZE observations; molecular clouds; system commissioning

Relevant Project: Yuan-Tseh Lee Array for Microwave Background Anisotropy (system scientist), ALMA-Taiwan (project manager), Submillimeter Array (polarization studies)

Keith Yeung

Education: M.A.Sc. in Electrical Engineering, University of British Columbia (1985), B.A.Sc., in Electrical Engineering, University of British Columbia (1977).

Expertise: Project management and leading large-scale technical development projects, project cost and risk analysis, RF & microwave design, real-time computer system design, digital and image processing, and robotic system design.

Relevant Project: ALMA Band 3 Receiver Project (Project Manager), JCMT HARP-B receiver local oscillator project (Canadian Project Manager and Design Engineer, managed the Canadian efforts in the development of the HARP-B receiver and developed the HARP-B local oscillator system), JCMT Receiver A3 (Electronics Engineer), GEMINI Enclosure Control System (Project Manager and Electronics Engineer).



Stéphane Claude

Education: Ph.D. in Physics, Queen Mary and Westfield College, London University, U.K. (1996), engineering degree in material sciences from the Ecole Nationale Supérieure d’Ingénieurs de Caen, France (1990).

Expertise: Design of radio-receivers for astronomy in the mm and sub-millimetre range.

Relevant Project: JCMT C2 Receiver (450-500 GHz): Superconductor-Insulator-Superconductor mixer (SIS) mixer fabrication and commissioning of the receiver. JCMT A3 Receiver (210-270 GHz): testing and commissioning of the receiver. Design of a sideband SIS mixer for operating at 100 GHz, 270 GHz and 345 GHz. ALMA Band 7 (275-370 GHz): receiver design. ALMA Band 3 (84-116 GHz): receiver design and systems engineer.

James Di Francesco

Education: Ph. D. in Astronomy, University of Texas at Austin (1997), B.Sc. in Physics and Astronomy, University of Toronto (1990).

Expertise: Star/planet formation and interstellar medium studies, millimetre-wave observational techniques, image processing and analysis, project management, programming.

Relevant Projects: Infrared Radiometry for Millimetre Astronomy (Project Scientist), GBT K-band Focal Plane Array (Team Scientist), JCMT Gould Belt Survey (Team Coordinator), Herschel Gould Belt and OB Young Stars surveys (Management Team member), interim Canadian ALMA Project Manager, interim Millimetre Astronomy Group Leader.

Leonardo Bronfman

Education: Ph.D. in Physics, Columbia University (1986).

Expertise: Galactic Mm-wave Astronomy.

Relevant Project: 1.2 m Southern Mm-wave Telescope (Project Scientist); U. Chile Mm-wave Laboratory (PI); ALMA Band 1 Prototype Receiver (PI); Band 5 ALMA Enhancement (CoI); Astronomical Instrumentation, Chilean Basal Center for Astrophysics and Associated Technologies (PI).

Ricardo Finger

Education: Ph.D. in Electrical Engineering (2011); Professional Degree in Electrical Engineering (2003); B.Sc. in Physics (2003), B.Sc. in Electrical Engineering (2001), Universidad de Chile.

Expertise: Radio Astronomy Instrumentation (mm-wave heterodyne receivers), Telecommunications.

Relevant Projects: ALMA Assembly Integration and Verification (RF engineer), Band 5 ALMA Enhancement (RF engineer), ALMA Band 1 Prototype receiver development.



Fausto Patricio Mena

Education: Ph.D. in Physics, University of Groningen, the Netherlands (2004); M.Sc. in Physics, University of Groningen, the Netherlands (2000); Physicist, Escuela Politécnica Nacional, Ecuador (1994).

Expertise: Design and construction of heterodyne receivers for radio astronomy, RF & microwave design, cryogenic testing (DC, RF and optical), tutorship of graduate and undergraduate students.

Relevant Project: Development of a prototype receiver for Band 1 of ALMA (Associate Investigator), Development of new instrumentation for the Southern mm-Wave Telescope (Principal Investigator), Design and construction of a 2SB receiver for Band 9 of ALMA (Instrument Scientist).

Nicolas Reyes

Education: PhD in Electrical Engineering, Universidad de Chile (candidate). Electrical Engineer, Universidad de Chile (2006), B.A.Sc., in Electrical Engineering, Universidad de Chile (2005).

Expertise: Microwave design and test of millimeter and RF components, millimeter wave systems design, instrumentation project management.

Relevant Project: Band 1 technology development, LNA for Band1, Upgrade of 115 GHz mini telescope at UCh.

Kamaljeet Saini

Education: PhD & MS in Electrical Engineering, University of Virginia, Charlottesville (2002 and 1997 respectively). Electronics and Communications Engineering, Birla Institute of Technology, India (1990).

Expertise: Systems Engineering, Design of centimeter, millimeter and sub-millimeter wave receiver systems, Electromagnetics modeling and simulation.

Relevant Project: ALMA FE System Engineer, Deputy Team Leader for the ALMA Front-End Group, Local Oscillator Engineer, ALMA Front-End Integration Center Test Systems Engineer, Receiver design engineer for the Giant Meter-wave Radio Telescope (GMRT).

Sivasankaran Srikanth

Education: M.S. in Electrical Engineering, the Ohio State University.

Expertise: Antennas, Optics, Passive microwave components.

Relevant Project: Feed horns and polarizers for Jansky Very Large Array, Very Large Baseline Array, and Green Bank Telescope (GBT). Responsible for the optics design of the GBT as a member of the design group. Developed quasi-optics for receivers in various NRAO telescopes.



John Effland

Education: M. S. in Electrical Engineering, George Washington University, 1982.

Expertise: Project Management, Measurement Systems, Software.

Relevant Projects: Band 6 and NA Front End Integration Center Co-Project Manager, integration of Band 6 NSI beam pattern software, team leader in design of measurement and configuration management databases and web-based software for Band 6 and FEIC, Design of portable G/T measurement system

Marian Pospieszalski

Education: Ph.D. in Electrical Engineering (1976) and M.Sc. in E.E. (1967), Warsaw University of Technology, Warsaw, Poland.

Expertise: Microwave, millimeter wave, and high–speed circuits and systems with special emphasis on theory and design of low-noise devices, amplifiers, and receivers for radio astronomy applications.

Relevant Project: Receivers for Jansky Very Large Array, Very Large Baseline Array, Green Bank Telescope, Cosmic Background Imager, Degree Angular Scale Interferometer, ArcMinuteMicroKelvin Imager, Wilkinson Microwave Anisotropy Probe radiometers, Low Frequency radiometers for Planck mission and many others.

Brian Mason

Education: Ph.D., University of Pennsylvania (1999); B.S., College of William & Mary (1994)

Expertise: Galaxy clusters, SZE, & observational cosmology; imaging algorithm development; centimetre and millimetre commissioning & observations (single dish and interferometer); in-lab instrument characterization; software development & project management; user support.

Relevant Project: MUSTANG bolometer array on GBT; GBT 30 GHz continuum backend & receiver; Cosmic Background Imager (compact 30 GHz interferometer); OVRO 5m & 40m 30 GHz radio telescopes.



7 Publications

[1] D. Johnstone, et al., “The Science Case for Building a Band 1 Receiver for ALMA,”astro-ph/0910.1609.

[2] N. Kaifu, et al., “Rotating gas disk around L1551 IRS-5,” A&A, 134, 7, 1984.

[3] K. Tatematsu et al., “Molecular cloud cores in the Orion A cloud. I.-Nobeyama CS (1-0) survey,” ApJ, 404, 643, 1993

[4] S. Casassus, et al., “Centimetre-wave continuum radiation from the rho Ophiuchi molecular cloud,” MNRAS, 391, 1075, 2008.

[5] B. Draine, and A. Lazarian, “Electric Dipole Radiation from Spinning Dust Grains,” ApJ, 508, 157, 1998.

[6] R. Rafikov, “Microwave Emission from Spinning Dust in Circumstellar Disks,” ApJ, 646, 288, 2006.

[7] R. A. Sunyaev and Ya.B. Zel'dovich, “The Observations of Relic Radiation as a Test of the Nature of X-Ray Radiation from the Clusters of Galaxies,” Comm. Astrophys. Space Phys., 4, 173, 1972.

[8] Y. Rephaeli, “Comptonization of the Cosmic Microwave Background: The Sunyaev-Zeldovich Effect,” ARA&A, 33, 541, 1995.

[9] D.R. Wik, et al. “The Impact of Galaxy Cluter Mergers on Cosmological Parameter Estimation from Surveys of the Sunyaev-Zel’dovich Effect,” ApJ, 680, 17, 2008

[10] P. Korngut, et al., “MUSTANG High Angular Resolution Sunyaev-Zel'dovich Effect Imaging of Substructure in Four Galaxy Clusters,” ApJ, 734, 10, 2011

[11] M. Markevitch & A. Vikhlinin, “Shocks & Cold Fronts in Galaxy Clusters,” Phys. Rep., 443, 1, 2007

[12] S. Ettori & A.C. Fabian, “Effects of sedimented helium on the X-ray properties of galaxy clusters,” MNRAS, 369, L42, 2006.

[13] C. Pfrommer, T.A. Ensslin,& C.L. Sarazin, “Unveiling the Composition of Radio Plasma Bubbles in the ICM with the Sunyaev-Zel’dovich Effect,” A&A, 430, 799, 2005

[14] M.J. Mortonson, W. Hu, & D. Huterer, “Simultaneous Falsification of LambdaCDM and Quintessence with Massive, Distant Clusters,” Phys. Rev. D, 83, 023015, 2011

[15] E.Daddi, et al., “Vigorous Star Formation with Low Efficiency in Massive Disk Galaxies,” ApJ, 673, L21, 2008.

[16] D. Obreschkow, et al. “Simulations of the Cosmic Evolution of Atomic and Molecular Hydrogen in Galaxies,” ApJ, 698, 1467, 2009

[17] D. Obreschkow, I. Heywood, &S. Rawlings, “Detecting Cold Gas at z=3 with ALMA and the SKA,” ApJ, 743, 84, 2011



[18] Front-End Sub-System for the 12 m Antenna Array Technical Specifications ALMA-40.00.00.00-01-A-SPE, 2007-04-17.

[19] “ALMA System Block Diagram,”ALMA-80.04.01.00-004-L-DWG.

[20] M. Carter, et al., “ALMA Front-end Optics Design Report,” and Appendix 1 ALMAEDM, http://edm.alma.clALMA-40.02.00.00-035-B-REP, 2007-07-19.

[21] Masahiro Sugimoto, “Front End Optics Design Report for ACA 7-m Antenna,” FEND-44.00.00.00-001-A-REP.

[22] S.-H. Weng, C.-H. Lin, H.-Y. Chang, and C.-C. Chiong, “Q-band Low Noise Amplifiers Using a 0.15-μm MHEMT Process for Broadband Communication and Radio Astronomy Applications,” Proceeding of International Microwave Symposium (IMS2008), Atlanta, June 2008, pp.551-554.

[23] Y.-J. Hwang, C.-C. Chiong, S.-W. Chang, T. Wei, W.-T. Wong, Y.-S. Lin, M.- T. Chen, H. Wang and H.-Y. Chang, “Cryogenic testing and multi-chip module design of a 31.3-45GHz MHEMT MMIC-based heterodyne receiver for radio astronomy,” Proc. SPIE 7020-68, Marseille, France, June 2008.

[24] C.-C. Chiong, H.-Y.Chang and M.-T. Chen, “Ka-Band Wide-Bandwidth Voltage-Controlled Oscillators in InGaP-GaAs HBT Technology,” Proceedings of European Microwave Conference (EuMW2008), Amsterdam, Oct. 2008, pp.358- 361.

[25] Y.-S. Lin, Y.-S.Hsieh, Y.-J.Hwang and C.-C. Chiong, “Q-band bandpass filter designs in heterodyne receiver for radio astronomy,” IEEE Asia-Pacific Conf. Circuits and Systems (APCCAS 2008), Macau, China, Nov. 2008.

[26] N. Reyes, P. Zorzi, F.P. Mena, C. Granet, E.Michael, L.Bronfman., “Design of a heterodyne receiver for Band 1 of ALMA,” Proceedings of the 20th International Symposium on Space Terahertz Technology (ISSTT2009), Charlottesville, April 20-22, 2009.

[27] S. Claude, F. Jiang, D. Dousset, N. Wren, I. Wevers, M. Fletcher, D. Henke and K. Wu,“ALMA Band 1 (31-45 GHz) Receiver Development at NRC-HIA,” Conference on Millimeter and Submillimeter Astronomy at High Angular Resolution, June 8-12, 2009, Taipei.

[28] Y.-S. Lin, Y.-S. Hsieh, C.-C. Chiong, Y.-J. Hwang, “Q-band GaAs bandpass filter design for ALMA band-1,” IEEE Microwave Wireless Comp. Letter, vol. 19, no. 6, pp. 353-355 June 2009.

[29] Y.-F. Kuo, Y.-J. Hwang, C.-C. Chiong, R.-M. Wen, and M.-T. Chen, “Phase- locked broadband GaAs HBT VCO module for millimeter-wave astronomical local oscillators,” Proc. 39th European Microwave Conf. (EuMC 2009), pp. 1824-1827, Rome, Italy, Sept.-Oct. 2009.

[30] Z.-M. Tsai, J.-C. Kuo, K.-Y. Lin, and Huei Wang, “A 24-48GHz Cascode HEMT mixer with DC to 15GHz IF bandwidth for astronomy radio telescope,” Proc. 4th European Microwave Integrated Circuit Conf., pp. 5-8, Rome, Italy, Sept. 2009.



[31] C.-C. Chiong, W.-J.Tzeng, Y.-J.Hwang, W.-T.Wong, H. Wang, and M.-T. Chen, “Design and measurements of cryogenic MHEMT IF low noise amplifier for radio astronomical receivers,” Proc. 4th European Microwave Integrated Circuit Conf. (EuMIC2009), pp. 1-4, Rome, Italy, Sept. 2009.

[32] P. Zorzi, D. Henke, S. Claude, P. Mena, L. Bronfman, and J. May, “Revisiting the ALMA Band 1 Optics Design,” 21st International Symposium on Space Terahertz Technology (ISSTT2010), March 2010, Oxford, UK.

[33] N. Reyes, P. Zorzi, C. Jarufe, P. Altamirano, F. P. Mena, J. Pizarro, L. Bronfman, J. May, C. Granet, and E. Michael, “Construction of a heterodyne receiver for Band 1 of ALMA,” 21st International Symposium on Space Terahertz Technology (ISSTT2010), March 2010, Oxford, UK.

[34] C. Granet, P. Mena, P. Zorzi, I.M. Davis, J.S. Kot, G. Pope, “Performance Comparison of Corrugated and Smooth-Walled Spline-Profile 31.3-45 GHz Horns for ALMA,” 4th European Conference on Antennas and Propagation (EuCAP 2010), 12-16 April 2010, Barcelona, Spain.

[35] D. Henke, S. Claude, F. Jiang, D. Dousset, and F. Rossi, “Component Development for ALMA Band 1 (31–45 GHz),” Proc. SPIE, San Diego, CA, Jun. 30, 2010.

[36] N. Reyes, C. Jarufe, F. P. Mena, J. Pizarro, L. Bronfman, and J. May,“Analysis of the Amplification System of ALMA Band 1,” SPIE Conference in Astronomical Telescopes and Instrumentation, July 2010, San Diego, California.

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ALMA Band 1 Receiver Development Study

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