Status of R&D on Calorimetry for EIC

1. Status of R&D on Calorimetry for EIC The EIC Calorimeter R&D Consortium Contact Persons: H.Z. Huang huang@physics.ucla.eduandC. Woody woody@bnl.gov S.Boose, E. Kistenev, E.Mannel, S. Stoll, A. Sukhanov, and C. Woody (PHENIX Group, Physics Department) E. Aschenauer, T.Burton, R.Darienzo and A.Kiselev (Spin and EIC Group, Physics Department) Y. Fisyak (STAR Group, Physics Department) Brookhaven National Laboratory W. Jacobs, G. Visser and S. Wissink Indiana University S. Heppelmann Pennsylvania State University C. Gagliardi Texas A&M University L. Dunkelberger, H. Z. Huang, G. Igo, K. Landry, Y. Pan, S. Trentalange and O. Tsai University of California at Los Angeles Y. Zhang, H. Chen, C. Li and Z. Tang University of Science and Technology of China EIC Detector R&D Committee Meeting June 5, 2013

2. Areas of Investigation • Tungsten Powder Epoxy Scintillating Fiber Calorimeter (W-SPACAL) • UCLA/IU/TAMU/PSU/BNL (STAR design) • Tungsten Scintillating Fiber Accordion Calorimeter • BNL (sPHENIX design) • SiPM readout system • BNL/IU (PHENIX + STAR) • BSO Crystal Calorimeter • USTC • Monte Carlo simulations (A.Kiselev’s talk) • BNL C.Woody, EIC Detector R&D Committee, 6/5/13

3. Dedicated EIC Detector Planar GEM Tracker ECAL Upstream low Q2 tagger HCAL ECAL RICH ECAL HCAL RICH TPC/HBD To Roman Pots DIRC/proximity RICH h -h C.Woody, EIC Detector R&D Committee, 6/5/13

4. Calorimeter Requirements • Endcap EMCAL at h < 0 (electron going direction) • Needs to be high resolution (~ 1-2 %/√E) in order to measure electron energy well (solenoid field does not provide good momentum resolution in forward/backward directions) • Best choice is scintillating crystals • PWO (similar to PANDA) • LSO/LYSO (excellent resolution but very expensive) • BSO (under development by this group) • Barrel EM calorimeter • Need ~ 12%/√E when combined with tracking • Want to be compact (short X0 and small RM) in order to fit inside solenoid • Best achieved with tungsten absorber with scintillating fiber readout • STAR design – tungsten powder epoxy with embedded scintillating fibers • sPHENIX design – tungsten metal plates with layers of scintillating fibers in between • Forward EM calorimeter • Assumed to be similar to barrel design • Forward and backward HCALs • Need ~ 50-100%/√E for single particles • sPHENIX HCAL (steel/scintillating tile with WLS fiber readout) • STAR forward HCAL (Pb/scintillator plates similar to ZEUS design) C.Woody, EIC Detector R&D Committee, 6/5/13

5. Progress on STAR Based Designs of Barrel EMCAL and F/B HCAL • The goal for this year is to build and test a new prototype of the sampling calorimeter for the EIC barrel EMCAL and develop a compact readout scheme utilizing multiple SiPM sensors to collect the light from a single tower. • EMCAL prototype will be built using the technology developed in Year 1 of this R&D with appropriate modifications for the barrel geometry (i.e. projective geometry). • A parallel R&D effort for the STAR forward upgrade (funded from STAR R&D) is continuing with the construction of a hadron calorimeter prototype (Pb/Sc plates, ZEUS prototype geometry) along with the EM calorimeter, both of which would use a multiple SiPMreadout. This design is considered as a potential candidate for EIC detector endcap. • Plan to test all of them together in a common beam test at FNAL. O.Tsai C.Woody, EIC Detector R&D Committee, 6/5/13

6. Requirements for compact readout guided by MC (shown at last meeting) • For Barrel; need high efficiency, can tolerate non-uniformity and some volume at the back of the tower with 100% sampling fraction (bundling fibers is permitted). • For EndCap; need good uniformity, can not tolerate significant area at the end of the tower with 100% sampling fraction (bundling of fibers is not possible). • Construction wise, no significant difference between EndCap and Barrel to build W/ScFi blocks. Interface for SiPM electronics is the same for EndCap and Barrel. Both schemes of readout will be tested during Test Run. Once light yield and resolution of detectors will be measured (target 500 P.E./ GeV) and compared with predictions future optimizations of these schemes will be made. O.Tsai Conservative approach for light collection schemes with SiPM readouts for our first try. C.Woody, EIC Detector R&D Committee, 6/5/13

7. New Barrel EMCAL Prototype O.Tsai C.Woody, EIC Detector R&D Committee, 6/5/13

8. HAD Prototype for STAR (ZEUS Pb/Scprototype design) 0.4 m x 0.4 m, 16 towers array, 4 Int. length long First W/ScFi prototype Tested in 2012 ( 2x2 super module) End of WLS Bar with string of SiPMs will be here. O.Tsai Construction - LEGO Style C.Woody, EIC Detector R&D Committee, 6/5/13

9. Status • All long lead time items ordered. All components for prototypes will be in hand by mid July. • Some parts for prototypes were already machined or are in production now at UCLA machine shop. • New type of epoxy was tested for construction of 2 x 2 super modules at once (instead of gluing them from two sub assemblies). Epotec 301-1 is much easier to work compare to Bicron BC600. • Summer students recruited at UCAL to run multiple tests for light collection optimization, characterization of SiPMs from Hamamtsu, and to perform final calibration of SiPM assemblies. • Main construction and test efforts will take place from July – September • Schedule for test run is not yet settled. Request to FNAL was sent almost two months ago for window Nov. 6 – Nov. 26 (last open window in 2013). FNAL has two requests for this slot, which were received at the same time. Still negotiating… O.Tsai C.Woody, EIC Detector R&D Committee, 6/5/13

10. Tungsten Scintillating Fiber Accordion Calorimeter (sPHENIX Design) • Progress since last meeting (Dec 2012): • We received 22 accordion shaped tapered thickness tungsten plates from Tungsten Heavy Powder (Phase I SBIR). Unfortunately they were the wrong thickness (~ 1.3 mm instead of 1.0 mm) due to a miscommunication between THP and the Chinese factory. • We nevertheless constructed a 2x7 tower prototype using these plates which allowed us to : • Investigate different types of adhesives for gluing sandwiches and forming the absorber stack • Develop a procedure for pre-forming scintillating fibers • Develop new tooling for constructing sandwiches and assembling absorber stack • Develop a procedure for gluing and assembling the absorber stack • Investigate white reflective epoxies for embedding fibers at readout end • Investigate white reflective paints and coatings for light collection cavities • Study the light collection efficiency and uniformity of light collection cavities • Produce a light collection cavity box for the prototype C.Woody, EIC Detector R&D Committee, 6/5/13

11. Difficulty Controlling Shape and Tolerances on Accordion Plates Plastic mold made to same desired shape as accordion plates • Tungsten plates undergo “spring back” during cooling. • Difficult to control shape to better than ~ 0.5 mm with current process • However, can do post annealing which can restore the shape to much better precision. However, this will increase • the cost. • Can also achieve very high precision for accordion shape with Electron Discharge Machining of pure tungsten metal. Can only do 20 cm wide plates, but cost should be much lower. Not giving up on the accordion, but we are also now looking at flat tapered plates that would be oriented at a small tilt angle to avoid channeling C.Woody, EIC Detector R&D Committee, 6/5/13

12. Making Sandwiches Single plate with fiber ribbon on top Fiber ribbon Sandwich after gluing • Fibers are glued together at ends to form ribbons • Ribbons have considerable spring back to be flat • Place ribbon in warm water bath (~ 80° C) to preform them into accordion shape • Glue preformed ribbon between two tapered thickness accordion plates (each ½ the final absorber thickness) to form a sandwich S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

13. Correcting for the Attenuation Length along the Fiber S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

14. Assembling and Gluing the Stack Stack of 10 sandwiches before gluing Stack inside gluing fixture developed by THP Tooling fixture allows for pitch of tapered plates Stack after gluing S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

15. Add a Diffusing Reflector on the Readout End • Want to cover ends of tungsten plates at the readout end of the stack with a diffusing reflector to improve light collection • Pot ends of fibers with a mixture of white reflector and epoxy • Opposite end is covered with a mirror reflector (Al mylar) S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

16. Towers are formed by Segmenting Readout End with Light Collecting Cavities 22 mm • Plastic collector box is made by 3D printing • Cavities are coated with a white diffusing reflector • SiPMs can be mounted to the top or sides of the cavities S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

17. Light Collection Efficiency and Uniformity Light output from fibers embedded in glue (measured with PMT) ~ 200 p.e./MeV  1000 g/MeV (Edep in scint) (PMT QE = 0.20) S.Stoll 4% sampling fraction  40 x 103g/GeV (Edep in cal) SiPM PDE ~ 0.25  10,000 x (Light Collection Factor) p.e./GeV in calorimeter • Light collection efficiency is ~ 3.5% with a single 3x3 mm2SiPM • Non-uniformity is ~ 40% (max/min) with single SiPM • Would expect ~ 14% efficiency and much better uniformity with 4 SiPMs • (next on our list….) C.Woody, EIC Detector R&D Committee, 6/5/13

18. Linearity and Dynamic Range • Increasing the number of readout devices increases the number of photoelectrons and improves the light collection uniformity of a single tower, but does not help with linearity (each device sees the same flux) • However, can lower flux and gain back p.e. yield by adding more devices, which does improve linearity • Questions: • Is it possible to passively add multiple SiPM outputs into a single preamplifier ? • Is it necessary to have separate bias stabilization, temperature compensation and gain adjustment (for matching) for each device ? Light Pulse Amplitude C.Woody, EIC Detector R&D Committee, 6/5/13

19. SiPM Readout Electronics (sPHENIX) • Common readout system usedfor EMCAL and HCAL • Preamp (voltage amplifier) • Temperature sensor (thermistor) • Feedback circuit to adjust bias voltage for temperature stabilization and control 12 bit 12 bit S.Boose Compensation of gain variation with temperature of a Hamamatsu S10931-025P • Setup for testing SiPMs • Bias control • Temperature stabilization • Linearity measurements See contribution to this year’s NSS/MIC by E.Mannel for details C.Woody, EIC Detector R&D Committee, 6/5/13

20. SiPM Readout Electronics (STAR) • Readout system being developed for SPACAL and STAR FCS (proposed) • Compact integrated module 22 × 22 × (25) mm3 • Four SiPM devices summed • Low power transimpedance amplifier (one for four SiPM) • Local bias voltage regulation from unregulated −90V input • Thermistor (one) compensates bias voltage with adjustable slope • Signal range >4000 pixel (for beam test) • Gain matching achieved by monitoring individual and summed single-pe signals prototype board (“unfolded”) layout in progress 21 × 21 mm2 sections interfaces, DAC, cable driver voltage regulators MPPC’s, preamp G.Visser C.Woody, EIC Detector R&D Committee, 6/5/13

21. sPHENIX EMCAL and HCAL Prototypes HCAL/EMCAL Prototype for beam test at Fermilab this fall sPHENIX Hadron Calorimeter C.Woody, EIC Detector R&D Committee, 6/5/13

22. Estimated Neutron Fluence at EIC At the Dec 2012 R&D Committee meeting, we reported a preliminary estimate of the average neutron fluence at EIC based on a Monte Carlo simulation using input from SSC and LHC estimates. For an integrated luminosity of 1041 cm-2, the average fluence at mid rapidity (R=5 cm) and forward rapidity (R = 30 cm, z = 8 m) was ~ 1010n/cm-2 Measured thermal neutron flux as a function od ZDC rate Installed thermal neutron counters in STAR Y.Fisyak C.Woody, EIC Detector R&D Committee, 6/5/13

23. Validation of Monte Carlo Calculation Compare measured thermal neutron flux to prediction from Monte Carlo (which gives spectrum over wide range of energies) Y.Fisyak C.Woody, EIC Detector R&D Committee, 6/5/13

24. R&D on Crystal Calorimeters (USTC) University of Science and Technology of China Improvements in large BSO crystals: Improved longitudinal transmission and uniformity Y.Zhang C.Woody, EIC Detector R&D Committee, 6/5/13

25. Improvements in Light output • Significant increase in the LY from SIC1301 to SIC1309. • SIC1301 gives minimum LY ~ 44 p.e./MeV. • SIC1308 and 1309 achieved 2x higher LY ~90 p.e./MeV. • Decay time ~100ns, 1308 and 1309 is a bit faster. Y.Zhang C.Woody, EIC Detector R&D Committee, 6/5/13

26. Radiation Damage in BSO • Damage is dose rate dependent • SIC1309 showed least amount of damage Y.Zhang C.Woody, EIC Detector R&D Committee, 6/5/13

27. Summary of R&D Over the Past 6 Months • Continued development of new W-SPACAL and HCAL prototypes by STAR Group • Constructed a 2x7 tower prototype of the tungsten scifiaccordion. Plates were not ideal, but it allowed us to develop the procedure for assembling the absorber stack and test various calorimeter components • Learned that current method for producing accordion plates will not allow achieving sufficient tolerances on larger plates. Will explore other methods for producing accordion plates and also investigate tilted tapered flat plate geometry • Produced and studied a number of BSO crystals and showedthat large crystals of very good quality could be produced. • Developed circuitry for bias stabilization and temperature control and reading out multiple SiPMsfor a single EMCAL tower. • Ordered 380 SiPMs (currently available Hamamatsu devices) for next prototype calorimetersas well as other long lead time items. • Requested time for a beam test at Fermilab later this fall C.Woody, EIC Detector R&D Committee, 6/5/13

28. Future Plans for the Next 6 Months • Complete construction of W-SPACAL prototype • Construct a new 7x7 tower prototype tungsten scifi calorimeter with tapered flat plates with 0.5 X0 sampling ( 12%/√E). • Continue development of the tungsten scifi design (both accordion and flat tapered plate) with a Phase II SBIR with THP aimed at the full calorimeter design. • Test all SiPMsand readout components for both W-SciFi prototype calorimeters. • CompleteSiPM control system and readout electronics for both W-SciFicalorimeters. • Complete sPHENIX and STAR HCAL prototypes (not part of this R&D activity) • Test both EMCAL/HCAL prototypes in a test beam at Fermilab later this year • Complete BSO calorimeter prototype and test in beam (either Fermilab or Beijing) • Order LYSO crystals for testing and comparison with BSO C.Woody, EIC Detector R&D Committee, 6/5/13

29. Budget Requests for Year 2 Funding BNL (same as in original proposal) USTC (additional $75K) UCLA and other institutions – no additional request at this time C.Woody, EIC Detector R&D Committee, 6/5/13

30. Backup Slides C.Woody, EIC Detector R&D Committee, 6/5/13

31. Uniformity across the Fiber Ribbon S.Stoll C.Woody, EIC Detector R&D Committee, 6/5/13

32. 11.50tilt Sampling Fraction of Accordion Calorimeter Simple answer based on dE/dx (for 0.6 X0 sampling) Azimuthal dependence of radiation length seen by straight through particle 2.4 mm W 2.1 mm 1.0 mm scint 1.0 mm 0.5 cm vs amplitude of oscillation of accordion vs tilt angle (sPHENIX HCAL - flat wedge plates) F 4.0% 3.6% 50tilt GEANT4 simulation using approximate accordion geometry f 1.25 cm C.Woody, EIC Detector R&D Committee, 6/5/13

33. The PANDA PWO Calorimeter Endcap 3864 crystals Barrel 11360 PWO-II crystals 200 mm long 15 GeV Positrons R. Novotny C.Woody, EIC Detector R&D Committee, 6/5/13

34. Cost of LSO From R.-Y. Zhu (Caltech), June 2012 C.Woody, EIC Detector R&D Committee, 6/5/13

35. Radiation Damage in SiPMs GlueX CMS C.Woody, EIC Detector R&D Committee, 6/5/13

36. New Hamamatsu SiPMs (MPPCs) • “Improved materials and wafer process technology” results in: • Reduced after pulsing and cross talk • Lower noise • Higher PDE • Wider dynamic range and better linearity (10 mm and 15 mm micropixel devices available) • Faster recovery time • Available in 1x1 mm2 and 3x3 mm2 devices C.Woody, EIC Detector R&D Committee, 6/5/13