R&D on CdTe pixel detectors - Centro de Astrobiología · PDF fileR&D on CdTe pixel...

Ins$tuto de Ciencias del Espacio (CSIC‐IEEC) AstroMadrid, 30th June 2011

R&D on CdTe pixel detectors J. Alvarez, J.L. Galvez, M. Hernanz, J. Isern

on behalf of a large collaboration with IMB(CNM-CSIC) and IFAE

LOFT – Large Observatory For x-ray Timing M. Hernanz, J. Alvarez, A. Caliandro, J.L. Galvez, J. Isern, N. Rea, D. Torres

Instituto de Ciencias del Espacio (CSIC-IEEC)

The EXPLOMEV project was approved and funded by Spanish Ministry of Science (2008-2012)

The goal of the technological part of this project is the research and development of a gamma-ray spectrometer with imaging and polarimetry capability and optimal spatial and energy resolution in the energy range of nuclear lines (from few hundred keV up to few MeV).

Perspective: R&D of a high performance focal plane detector based on room temperature semiconductor detectors (CdTe/CZT) for the next generation of hard X and soft gamma ray telescopes based on Laue lenses.

Currently: Design and development of a CdTe/CdZnTe pixel detector array for polarimetry. Considered as a payload option for a balloon-borne experiment with a CdTe/CdZnTe polarimeter, currently under study.

Explomev project


GRI- 2007 DUAL-2010

Meeting, 23-24 February 2011, Barcelona

Detector requirement for a reliable measurement of the CRAB polarisation state. High energy sources to be observed. Study of the CZT(CdTe) detector configuration to improve polarisation

sensitivity. Gondola requirement (e.g. pointing accuracy and stability). Other partner. Proposal organisation and tasks/responsibilities sharing.

A Balloon-Borne 3D CZT(CdTe) Scattering Polarimeter for Hard X-Ray Astrophysics

Heritage CIPHER: coded imager and polarimeter for high-energy radiation

E. Caroli et al. NIMA, Vol 448, 525-530 (2000)


A Balloon-Borne 3D CZT Scattering Polarimeter for Hard X-Ray Astrophysics

E. Caroli1, J. M. Alvarez2, N. Auricchio1, C. Budtz-Jorgensen3, R.M. Curado da Silva4, S. Del Sordo5, J. L. Galvez2, M. Hernanz2, J. Isern2,I. Kuvvetli3, J. M. Maia Pereira6, J. B. Stephen1, A. Zappettini7

1INAF/IASF-Bologna, Bologna, Italy 2IEEC-CSIC, Instituto de Ciencies del Espacio, Barcelona, Spain

3DTU Space, Copenhagen, Denmark 4LIP, Coimbra, Portugal

5INAF/IASF-Palermo, Palermo, Italy 6Physics Dept., University of Breira Inerior, Covilha, Portugal

7IMEM/CNR, Parma, Italy

It is widely recognized that a measurement of the polarization of the high energy emission from cosmic sources is a key observational parameter which will aid in the understanding of the nature of high energy cosmic ray astrophysics. Therefore new instrumentation operating in this energy range should exhibit a good sensitivity also for this type of measurements. Herein we present the concept of a small high performance detector optimized for polarimetry between 100 and 500 keV suitable for use with stratospheric balloon-borne payload dedicated to obtaining accurate measurements of the polarization of the Crab pulsar. The detector with 3Dspatial resolution is based on CZT spectrometer sensitive units in a highly segmented configuration suitable for operation as a high quality scattering polarimeter. We describe recent development results and possible improvement currently under study. The proposed payload can be also considered as a pathfinder for a high performance focal plane detector for the next generation of hard X and soft gamma ray telescopes based on Laue lenses.



Balloon-borne payload option

CdTe/CdZnTe pixel detector array for polarimetry

Background Studies


Planar Transverse Field (PTF) configuration

Focal plane detector of a Laue lens - Caroli et al, Experimental Astronomy, 20, 341 (2005)



Incomplete charge collection in CdTe

Simulated Pulse Height spectra with Geant4 – Hecht equation

Planar Transverse Field (PTF) configuration

Focal plane detector of a Laue lens - Caroli et al, Experimental Astronomy, 20, 341 (2005)



CdTe/CdZnTe pixel detector array

Geant4 model

Background Studies

GR

HV bias

CdTe array 11x11 Dimensions: 12.15mm x 12.15mm x 2mm The pixel size: 1mm x 1mm Guard ring: 1 mm Structure: Pt//CdTe//Pt (Ohmic contacts for electron collection)‏ On the pixel side: Au/Ni/Au Manufactured by Acrorad (Japan)

Fanout board

Pitch adapter board

- Glass substrate with metal tracks to connect the 121 pixels to the readout chip channels.

- Mechanical support

Design of the pixelated CdTe prototype


Zoom of the fanout’s pads

Stud Bump Bonding process in collaboration with RAL (UK)

Ni-Au deposition in the fanout to ensure the good bump bonding connectivity.

FAILED SUCCEED

ASIC NUCAM

Fabricated in the IMB(CNM-CSIC) clean room

Two masks required: Metallisation and Passivation

CdTe

Au pad on CdTe

Au Stud s on Ni-Au-Al pad

Ni-Au on Au pad

Fanout

Ni-Au-Al pad

Fabrication of a pixelated CdTe prototype


ASIC NUCAM

NUCAM ASIC

CdTe

CdTe pixel detector with the NUCAM ASIC low-noise read-out

NUCAM ASIC developed by RAL (UK) Low Noise 128-Channel ASIC

NUCAM ASIC P. Seller et al,IEEE Nuclear Symposium Conf. Rec., vol 6, pp. 3786-3789, 2006

Two dynamic ranges (200keV, 350keV)

On-chip ADC with 12 bits resolution.

Leakage current compensation (adjustable): up to 4 nA.

Noise level: <100e- rms@2pF (Shaping Time=7.5µs) at room temperature.

Threshold level( adjustable):10keV -40keV range.

Shaping time: 0.5µs - 7.5µs range.

Power consumption/channel ~2 mW at max RW rate (min rate 10kHz)

First pixelated CdTe prototype


Test of a pixelated CdTe prototype

FWHM @ 356keV -> 2.6% FWHM @ 59keV -> 9.2%

T=-10ºC Bias=-400V

Ongoing studies on the performances: Noise determination (Leakage-current

measurement). Charge sharing. Correction of the Incomplete Charge Collection.

J. Alvarez et al. NIMA 623,434 (2010), J. Alvarez et al. SPIE, 7732 (2010)


CdTe/CdZnTe pixel detector for gamma-ray spectrometry with imaging and polarimetry capability in astrophysics

J. M. Alvarez1, J. L. Galvez1, M. Hernanz1, J. Isern1, M. Lozano2, G. Pellegrini2, M. Chmeissani3, E. Caroli1,R.M. Curado da Silva4

1IEEC-CSIC, Institut de Ciencies de l'Espai, Barcelona, Spain 2Centro Nacional de Microelectronica (IMB-CNM(CSIC)), Barcelona, Spain

3Institut de Fisica d'Altes Energies (IFAE) 4INAF/IASF-Bologna, Bologna, Italy

5LIP, Coimbra, Portugal

Gamma-ray astrophysics in the MeV energy range plays a crucial role for the understanding of many exciting cosmic phenomena such as stellar explosions or cosmic accelerators (e.g., Supernovae, Novae, Supernova Remants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, etc). Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) are very attractive materials for gamma-ray detection which have a great potential for imaging, spectroscopy and polarimetry in instruments onboard current gamma-ray space missions (such as IBIS/INTEGRAL and BAT/SWIFT). However, the energy coverage of these instruments has been limited up to a few hundred keV, and there has not been yet a dedicated instrument for polarimetry. Our technological activities aim to develop a gamma-ray spectrometer based on CdTe/CdZnTe detectors, with imaging and polarimetry capability, for astrophysical applications within the energy range from a few hundred keV up to a few MeV. After developing and testing an initial prototype based on CdTe bidimensional segmented anode, performance studies are being carried out in a customized vacuum chamber with a cooler that allow us to control the detector temperature down to -30C. Results of these measurements are reported here. Additionally, the design of a CdTe/CdZnTe pixel detector array for polarimetry are presented. This design is one of the options for a balloon-borne experiment with a CdTe/CdZnTe polarimeter, currently under study (E. Caroli et al. in these proceedings).



Instrument option

CdTe/CdZnTe pixel detector array for polarimetry

Background Studies


Background Studies Measured and simulated background in the Nuclear Compton Telescope (E.Boggs et al.) balloon flight (NASA’s Balloon Payload). The powerful simulation tools developed for Advanced Compton Telescope and used in this experiment is available at the Institute of Space Science (CSIC-IEEC).

CLAIRE balloon flight 2002 (P. von Ballmoos et al.)


R&D on CdTe pixel detectors J. Alvarez, J.L. Galvez, M. Hernanz, J. Isern

on behalf of a large collaboration with IMB(CNM-CSIC) and IFAE

LOFT – Large Observatory For x-ray Timing M. Hernanz, J. Alvarez, A. Caliandro, J.L. Galvez, J. Isern, N. Rea, D. Torres

(CSIC-IEEC)

Instituto de Ciencias del Espacio (CSIC-IEEC)


currently in a LOFT meeting in ESTEC

LOFT is a medium-class mission selected for the assessment phase of the ESA M3 Cosmic

Vision call


ESA’s Soil Moisture and Ocean Salinity (SMOS) satellite –Launch November 2009-


LOFT’s Wide Field Monitor (WFM) Meeting 21th-22th June, Barcelona


Geant4 simulations of a WFM unit

E = 10keV

Field of view one WFM-Unit

Effective Area Mask (300 x 300 mm) Tungsten : 150um 50% open area

Collimator: (support + shielding) Carbon Fibre : 1mm Tungsten : 150um

Detector (200 x 200 mm) Silicon : 450um Coating : Al (10 um) Backshield 1 : Al 1mm (radiator) Backshield 2 : W (200um)

Vignetting

10um Al (see mass model)


http://www.isdc.unige.ch/loft/index.php/the-loft-mission Ins$tuto de Ciencias del Espacio (CSIC‐IEEC) AstroMadrid, 30th June 2011

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