July 4, 2014

Jamie L. Rhee, Chief Procurement Officer Attention: Jacoby Radford, Assistant Procurement Officer Department of Procurement Services Bid and Bond Room - Room 301 City Hall 121 North LaSalle Street Chicago, Illinois 60602 Dear Mr. Rhee, Having read the mayor’s initiative to illuminate Chicago via the City-Wide Lighting Framework Plan Spec # 124831, I am proposing a new interactive science and art exhibit “Cosmic Rays Over Chicago” that would become part of the steel trellis at the Jay Pritzker Pavilion. This exhibit would make cosmic rays from exploding stars throughout the universe visible directly and would bring more evening visitors to Millennium Park. Illumination would be subtle, so that the majestic lines of the trellis would be left undisturbed. This submission does not address the grand scale of the current RFP, however it provides a compelling underlying reason for the illumination of this iconic structure, as well as a way to thematically link several areas of tourist visitation. This proposal does address RFP items of Vision, Light Needs Darkness, Networks and Iconic Structures. I (Mark Adams) agree to be bound by the terms contained in this RFP; and I serve as the primary contact. I propose that forty-three cosmic ray detectors be mounted on top of the trellis, mostly hidden from view and located approximately every ten meters. LED lights mounted at the detector locations would gently flash when comic rays pass through the detectors. The constantly changing pattern of glowing detectors against the dark sky would capture visitors’ attention. Lights on top of the trellis joints would be visible from outside the park and LED’s mounted below the trellis would illuminate sections of the trellis, creating a light pattern above the heads of the visitors near the lawn. A set of twenty-three additional detectors would be located on the ground, ringing the lawn’s outer walkway; encouraging visitors to stand on the detectors and be illuminated themselves, making the public a part of this stardust catcher. I envision a dual role for this exhibit. The first goal is to illuminate the trellis to highlight the shower of particles from supernovae, as described above. The second goal is to incorporate the Millennium Park detectors as the central location of a larger collection of detectors already in operation in several area high schools and universities. All cosmic ray data would belong to the

public. If the city wished, additional detector arrays could also be designed for the Alder Planetarium, Navy Pier and future Lucas Museum, creating a network for some of the city’s major tourist destinations. I proposed a similar project to Frank Gehry in 2005, albeit unrelated to any city initiative. After his office expressed interest and contacted the city, the Millennium Park engineers and I created a prototype, which he reviewed. I believe that this updated concept for illumination is more appropriate for this iconic structure and I hope it is worthy of your consideration at the appropriate stage. At that earlier date, a member of the Board at Adler also indicated interest in hosting a detector of this design. I hope the committee is excited about the opportunity to bring parts of the cosmos to the public at Millennium Park. This unique project would join the leading-edge Illinois detector technology developed at Fermilab with Chicago’s major lighting initiative. Mark Adams of the University of Illinois will supervise the cosmic ray detector design, Sten Hansen of Fermilab will design the front-end electronics and readout, and Jim Jenkins of Jenkins Arts will design detector containers, lighting and public artwork. Sincerely, Professor Emeritus Mark Adams adams@uic.edu 630-508-7459 cell

Cosmic Rays Over Chicago Executive Summary

This submission does not address the grand scale of the current RFP, however it provides a compelling underlying reason for the illumination of the iconic Pritzker Pavilion, as well as a way to thematically link several other areas of tourist visitation. This proposal does address RFP items of Vision, Light Needs Darkness, Networks and Iconic Structures. The Team has been formed explicitly to build a cosmic ray detector on and around the trellis of the Pritzker Pavilion. This project is only possible because of the vast technical experience members have gathered through their High Energy Physics studies at Fermilab. Adams is the principal contact and has been a member of the High Energy Physics group at the University of Illinois at Chicago for 29 years, with experience building detectors for elementary particle searches, including the top quark and Higgs boson, at Fermilab and at the Large Hadron Collider at CERN. For over a decade, he has also assembled a cosmic ray collaboration of high schools throughout Chicagoland through the NSF’s QuarkNet educational outreach program. Adams previously discussed a similar project in 2005 with the Pritzker Pavilion’s architect Frank Gehry and Millennium Park personnel. Mark Adams, UIC Professor Emeritus adams@uic.edu Physics Department University of Illinois at Chicago 845 W. Taylor St. Chicago, IL 60607 630-508-7459 Hansen is an electrical engineer in the Particle Physics Division at Fermilab. The envisioned cosmic ray detector requires state of art photodetectors and readout systems. Hansen has designed such systems for several large physics collaborations. He also designed the data acquisition boards, used around the world, that are the technical heart of the NSF’s QuarkNet cosmic ray program. Our Pritzker Pavilion detector will borrow generously from a system he is currently developing for the Mu2e collaboration at Fermilab. Sten Hansen Fermilab Electrical Engineer hansen@fnal.gov Particle Physics Division MS 222 WH 14 E 630-840-4027 Jenkins is an artist who specializes in sculptures that link art and science. He provides expertise on communicating ideas visually to the public. He will design detector containers, help construct prototypes and develop informational messages that will be laser-cut into stainless rings housing the ground detectors. Jenkins will also coordinate with the selected theatrical lighting vendor. Jim Jenkins jim@jenkinsarts.com

http://www.jenkinsarts.com/

Figure 1. Cosmic Rays Over Chicago Lights from Cosmic Rays.

Cosmic Rays Over Chicago

Project Understanding and Approach

The Cosmic Rays Over Chicago Team has been formed explicitly to build a cosmic ray detector on and around the trellis of the Pritzker Pavilion, using technology developed in Illinois. This project is only possible because of decades of detector design by members of the team, the vast technical resources available at Fermilab, and the experience gained with the cosmic ray detectors of the UIC QuarkNet program http://physicsweb.phy.uic.edu/quarknet/. The lighting system for the Pritzker Pavilion trellis is driven by the presence of several muons that arrive simultaneously from a high energy cosmic ray shower that was initiated in the upper atmosphere. Lights are a critical component and will be developed with consultation of a theatrical lighting firm. However, the cosmic ray components described in detail in following paragraphs present the largest technical challenges and will require two phases of prototyping. Each cosmic ray detector operates independently, but reports its data to a central computer (CC). Lights are located at the detectors, providing visualization of the cosmic ray shower for the public. The resulting patterns of lights representing muon trajectories will be flashed at most every several seconds, so that the rate of display is pleasing to visitors. Decisions about which lights to illuminate take place in the CC, because the array must be interrogated to determine which detectors were hit by muons together during a cosmic ray shower. Each detector observes 5 muons per second. Since there are 66 detectors in the full array (43 on the trellis and 23 in the walkway), there are approximately 330 muon signals per second. Information containing which detector was hit by a muon, the muon’s arrival time within 2 ns, and the signal’s integrated size in a 100ns time window, is temporarily buffered locally, and then forwarded approximately every millisecond to the CC along one Category 5 cable for each trellis arc. At the CC, information is collected and cosmic ray shower events are reconstructed based on the muons’ times. Muons travel near the speed of light (3x108 m/s), but can come from any direction in the sky, so events are assembled from hits occurring within approximately 1 microsecond of each other. An absolute time stamp provided by a GPS receiver is distributed to each detector. All communication and power to the detectors is provided on one Category 5 cable running the length of each arc. Detectors are constructed from extruded scintillation counters. Muons traversing the counters deposit energy, excite atoms that emit a small amount of light. The light is captured, reemitted by green wave-shifting optical fibers and directed to a photodetector. Commercially available silicon photomultipliers (SiPM) (http://www.hamamatsu.com/us/en/index.html) with gains of 105 convert the photoelectrons into a small electrical signal that is digitized both in time and in charge using an ultrasound processing chip. Extensive experience with muon detectors in high energy physics experiments has been gained at Fermilab. The designer of the QuarkNet

readout electronics, as well as of high energy physics experiments’ front end readout systems will lead the design of the Pritzker Pavilion readout system. The CC communicates back to the detectors hit by muons in an event so that they can turn on their local lights for a 1-second flash, representing the pattern of muons detected in the cosmic ray shower. Power is supplied to the lights on a separate cable to isolate the sensitive detector electronics and lighting systems.

Figure 2. Overhead view of the Pritzker Pavilion trellis with cosmic ray detectors.

Figure 3. Illuminated ground cosmic ray detectors.

Figure 4. Conceptual design of a detector located on the trellis. Because of the high rate of events containing only one muon-hit detector, only the subset of cosmic ray events containing multiple muons traversing multiple detectors are used to illuminate the trellis. However, all muon data is recorded and available to the public via QuarkNet’s e-Lab https://www.i2u2.org/elab/cosmic/home/project.jsp. This project will create analysis modules for e-Lab and allow cosmic ray data at the Pritzker Pavilion to be combined with data from other Chicago sites. Google Map with QuarkNet and Pritzker Pavilion comic ray site: https://mapsengine.google.com/map/edit?mid=zl9zMEZG24yo.krRrsGgWP3mQ

Figure 5. Static version of a google map of UIC QuarkNet cosmic ray sites and the proposed new sites for this project. Components of the system: 1. Extruded Scintillation detectors will be mounted on the trellis, as well as on the ground around the walkway. Similar extruded strip systems have been developed for high energy physics experiments. One hundred thousand detectors were constructed for MINOS at Fermilab http://www-numi.fnal.gov/index.html as well as muon detectors for CMS http://www.uslhc.us/The_US_and_the_LHC/Collaborating_Institutions/Fermilab at CERN. Current prototype detectors for the Fermilab Mu2e experiment http://mu2e.fnal.gov/ have demonstrated acceptable extrusion capability, sufficient light yield, (~30 photoelectrons), SiPM control and readout. Sketches of a detector on the trellis is shown in figure 6 and a cross section of the extruded scintillator is seen in figure 7. An extrusion factory has been in operation at Fermilab’s Lab 5 for over a decade and our project will piggy-back on development by Mu2e.

Figure 6. Drawings of scintillation detector components on Pritzker Pavilion trellis.

Figure 7. Cross section of extruded scintillator, showing holes for wave-shifting fiber. 2. The photodetector and readout poses the largest technical challenge, however the designer for Mu2e will lead the effort for the Cosmic Rays Over Chicago. SiPMs detect the light from each wave-shifting fiber. Either one SiPM package per fiber as in the Mu2e design or one 16-channel SiPM per detector (as drawn) will be implemented, depending on results from our prototype effort. SiPMs have a large noise rate for single photoelectrons, however our detectors will generate enough light to set a threshold at greater than three photoelectrons. Remaining electronic noise will be minimal and most signals will be from muons. SiPMs require an operating bias voltage of 40v-100v which depends on temperature. Controlling the temperature is difficult. Instead, the temperature will be continuously monitored and the bias adjusted. The system acts as a digital device (a muon hit detector or not), but an Analog to Digital Converter is important for calibration and gain adjustment. Sixty thousand SiPMs were operated by the T2K experiment in Japan for years with very low failure rates [Yokoyama, “Performance of Multi-pixel Photon Counters for the T2K Near Detector”, Nuclear Instruments and Methods A622, 567 (2010)], so the technology is robust. 3. Most electronics for control, clock and readout will reside inside the detector boxes. Data from all detectors will be digitized and buffered locally. All detectors located on one arc of the trellis transfer information to the CC along one daisy-chained Category 5

cable. A data concentrator card will gather data from each trellis arc. Concentrators will communicate to the CC over point-to-point Ethernet. 4. A GPS receiver and distribution provides an absolute time stamp for muons at each detector. A GPS receiver used in QuarkNet contains a calibration pulse every second that allows absolute time for the array to be determined to 200ns and relative timing among detectors to approximately 2 ns. The absolute time enables analyzers to correlate Pritzker events with events from other sites. Precise relative timing determines the sensitivity of the reconstructed cosmic ray direction at the Pritzker Pavilion. 5. Signals from all detectors are collected at the CC and hits within 1 microsecond are assumed to consist of one shower event. If the multiplicity of hits in one event exceeds three, those detectors are commanded to flash their corresponding lights. This processing happens faster than humans can detect, so the light pattern appears to be simultaneous with the cosmic ray shower in real time. 6. There are two lights at each detector on the trellis cylinders: one unit below to illuminate trellis and one on top to shine horizontally. Theatrical lighting firms will be consulted for the appropriate technology. Lighting control remains with the CC. 7. Data will be transferred to the QuarkNet e-Lab, which is maintained by Fermi staff, whose servers currently reside at Argonne National Lab. 8. Because Pritzker Pavilion data will be more complex than current QuarkNet cosmic ray data, decoding and analysis software modules will be developed for e-Lab by Adams and UIC students. Milestones and Facilities Detectors and readout must be constructed in three phases: prototype, 10% test and production. Further details, including detailed budgets will be provided if this project is involved in future phases of the RFP. Locations of Activities: At Fermilab: readout design and production by engineers in the Particle Physics Division; initial electronic testing; scintillator extrusion at factory located at Lab5; wave-shifter fiber polishing at Lab6. At Jenkinsart, Batavia, IL: disc detector and lighting design; hermetic box development. At UIC: machining of weatherproof boxes; assembly of detectors; vertical test stand for integrated testing; analysis modules developed for e-Lab by UIC staff. At Pritzker Pavilion: installation; data gathering; public art! Prototype phase Prototype detector material costs are minimal. Most expenses are incurred via personnel and much of that effort will be donated by Fermilab and UIC staff. A post doc (or someone with that skill set) will be required to help Adams develop the prototypes of

detectors, select SiPM and electronics designs, design hermetic boxes, develop readout and data acquisition, write the initial analysis programs and supervise performance and lifetime testing. 10% test phase An entire detector system, including lighting, for one trellis arc must be constructed, tested, mounted on the trellis (or on a mockup) and retested before production of all detectors can proceed. There are many electronics systems that might interact: detectors, readout, lighting, existing speakers, etc. These detectors will probably be acceptable for use in the final detector system, however, it should be anticipated that all readout cards will be replaced, since the final design may evolve. Production phase Production of all detector and readout components for the final 66-detector system. assembly and testing will require six months. Installation should be a rather fast process of a few weeks, and will benefit greatly from existing Millennium Park expertise. Operation and Analysis phase Monitoring of detectors, readout, lighting displays, website, and operation are the first critical tasks. A small team of Adams and UIC students will continue to support the detector after the first year of operations. Although the primary role of the Pritzker Pavilion detector and the existing CLASA array are public scientific art and education, there is also a scientific goal that is critical to the participation of any post doc. Observation of high energy cosmic ray showers that cover much of Chicago will provide unique information to the astronomical research community. Necessary analysis steps of the cosmic ray showers include selection of valid showers from electronic backgrounds, calibration of detector timing, detector performance studies, calculation of shower direction and muon multiplicity, modeling of the detector array geometry, simulation of showers using astronomical research program (e.g. AIRES), extraction of shower energy, and search for time correlation of Pritzker Pavilion cosmic ray events with those recorded throughout the rest of the city in the CLASA array. GRID analysis tools in e-Lab that were developed for QuarkNet programs in the US must be modified to include the new data format from Cosmic Rays Over Chicago. Decommissioning Final dismounting at the end of the life of the cosmic ray exhibit.

Figure 8. Cosmic Rays Over Chicago Organizational Chart.

MBE/WBE Enterprises The Team is not a business and has no experience with MBE/WBE enterprises, however, Adams’ yearly QuarkNet summer cosmic ray workshops for high school students have trained over 70 students during the last five years. Over half of the participants come from underrepresented minority groups and 45 percent are women. We expect that this strong record will continue when employing people in this proposal. We will make good faith efforts with our only anticipated full-time hire to identify a postdoc who satisfies the MBE/WBE criteria. The three labs at Fermilab with which we will consult are all supervised by women: Lab 5 extrusion facility; Lab 6 fiber polishing and the Fermilab QuarkNet group. The selection of the theatrical lighting firm will also represent an opportunity to address the MBE/WBE enterprise criteria.

Cosmic Rays Over Chicago Company Profile

The Cosmic Rays Over Chicago Team has been formed explicitly to build a cosmic ray detector on and around the trellis of the Pritzker Pavilion. This project is only possible because of the vast technical experience members have gathered through their high energy physics studies at Fermilab. We are a collaboration of a physicist from UIC, and electrical engineer from Fermilab and a sculptor. The Team feels that creating a business enterprise for this RFP would not allow us to utilize the many resources and expertise at UIC and Fermilab that will be matched or donated under a research grant or non-profit structure. If this project becomes part of the next stage of Chicago’s illumination project, we would be happy to discuss an alternative organizational scheme that the city deems more appropriate. This submission does not address the grand scale of the current RFP, however we hope that it becomes part of the design project for the Pritzker Pavilion.