Status of R&D on Calorimetry for EIC EIC Detector R&D Committee Meeting June 5, 2013 The EIC Calorimeter R&D Consortium Contact Persons: H.Z. Huang and C. Woody 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

Areas of Investigation C.Woody, EIC Detector R&D Committee, 6/5/13 2  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

Dedicated EIC Detector C.Woody, EIC Detector R&D Committee, 6/5/13 3 To Roman Pots Upstream low Q 2 tagger ECAL DIRC/proximity RICH   TPC/HBD Planar GEM Tracker

Calorimeter Requirements C.Woody, EIC Detector R&D Committee, 6/5/13 4 Endcap EMCAL at  < 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 X 0 and small R M ) 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 ~ 40%/√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 Tungsten Powder Epoxy SciFi Calorimeter Progress since last meeting (Dec 2012): Short summary of what has been done

C.Woody, EIC Detector R&D Committee, 6/5/13 6 Slides from Oleg

Tungsten Scintillating Fiber Accordion Calorimeter C.Woody, EIC Detector R&D Committee, 6/5/13 7 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 assembly 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 8 Difficulty Controlling Shape and Tolerances on 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 Plastic mold made to same desired shape as accordion plates

C.Woody, EIC Detector R&D Committee, 6/5/13 9 Making Sandwiches S.Stoll 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 Fiber ribbon Sandwich after gluing Single plate with fiber ribbon on top

C.Woody, EIC Detector R&D Committee, 6/5/13 10 Correcting for the Attenuation Length along the Fiber S.Stoll

C.Woody, EIC Detector R&D Committee, 6/5/13 11 Assembling and Gluing the Stack S.Stoll Stack of 10 sandwiches before gluing Stack inside gluing fixture developed by THP Tooling fixture allows for pitch of tapered plates Stack after gluing

C.Woody, EIC Detector R&D Committee, 6/5/13 12 Add a Diffusing Reflector on the Readout End S.Stoll 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)

C.Woody, EIC Detector R&D Committee, 6/5/13 13 Towers are formed by Segmenting Readout End with Light Collecting Cavities S.Stoll 22 mm Collector box is 3D printed from engineering drawing Cavities are coated with a white diffusing reflector SiPMs can be mounted to the sides of the cavities

14 C.Woody, EIC Detector R&D Committee, 6/5/13 Light output from fibers embedded in glue (measured with PMT) 4% sampling fraction  40 x 10 3  /GeV (E dep in cal) SiPM PDE ~ 0.25  10,000 x (Light Collection Factor) p.e./GeV in calorimeter Light Collection Efficiency and Uniformity Light collection efficiency is ~ 3.5% with a single 3x3 mm 2 SiPM Non-uniformity is ~ 40% (max/min) with single SiPM Would expect ~ 14% efficiency and much better uniformity with 4 SiPMs (next on our list….) ~ 200 p.e./MeV  1000  /MeV (E dep in scint) (PMT QE = 0.20)

Linearity and Dynamic Range 15 C.Woody, EIC Detector R&D Committee, 6/5/13 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 Can add inputs passively into a single preamplifier or have a separate preamp for each device Is it necessary to have separate bias stabilization, temperature compensation and gain adjustment (for matching) for each device ? Light Pulse Amplitude

SiPM Readout Electronics (PHENIX) 16 C.Woody, EIC Detector R&D Committee, 6/5/13 Readout system being developed for sPHENIX Preamp (voltage amplifier) Temperature sensor (thermistor) for each SiPM Feedback to bias voltage for temperature stabilization and control Also developing 12 bit ADC Setup for testing SiPMs Bias control Temperature stabilization Linearity measurements 12 bit Compensation of gain variation with temperature of a Hamamatsu S P See contribution to this year’s NSS/MIC by E.Mannel for details

C.Woody, EIC Detector R&D Committee, 6/5/13 17 SiPM Readout Electronics (STAR) Readout system being developed for SPACAL and STAR FCS (proposed) Compact integrated module 22 × 22 × (25) mm 3 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 interfaces, DAC, cable driver voltage regulators MPPC’s, preamp 21 × 21 mm 2 sections G.Visser

Radiation Damage in SiPMs C.Woody, EIC Detector R&D Committee, 6/5/13 18 GlueX CMS

C.Woody, EIC Detector R&D Committee, 6/5/13 19 Neutron Flux measurements from STAR Slides from Oleg

C.Woody, EIC Detector R&D Committee, 6/5/13 20 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  m and 15  m micropixel devices available) Faster recovery time Available in 1x1 mm 2 and 3x3 mm 2 devices

C.Woody, EIC Detector R&D Committee, 6/5/13 21 R&D on Crystal Calorimeters Progress since last meeting (Dec 2012): Short summary of what has been done

C.Woody, EIC Detector R&D Committee, 6/5/13 22 Slides from Yifei

Summary of R&D Over the Past 6 Months 23 Continued development of the new W-SPACAL prototype Constructed a 2x7 tower prototype of the tungsten Scifi accordion. 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 determined that crystals of suitable quality could be produced. Developed circuitry for bias stabilization and temperature control of SiPMs and for reading out multiple SiPM in a single readout channel. Ordered 380 SiPMs (currently available Hamamatsu devices) for next prototype calorimeters as well as other long lead time tiems. Requested time for a beam test at Fermilab later this fall C.Woody, EIC Detector R&D Committee, 6/5/13

Future Plans for the Next 6 Months 24 Complete construction of new W-SPACAL prototype Construct a new 7x7 tower prototype tungsten SciFi accordion calorimeter with tapered flat plates which will have 0.5 X 0 sampling (  12%/√E). Complete BSO calorimeter prototype Develop SiPM control and readout electronics for both W-SciFi prototype calorimeters. Test all SiPMs for both detectors. Test both W-SciFi calorimeters in a test beam at Fermilab later this year Test BSO calorimeter in test beam (either Fermilab or Beijing) Order LYSO crystals for testing and comparison with BSO C.Woody, EIC Detector R&D Committee, 6/5/13

Budget Requests for Year 2 Funding C.Woody, EIC Detector R&D Committee, 6/5/13 25 BNL (same as in original proposal) USTC (additional $75K) UsageCost (kUSD) LYSO samples purchase aim for a 3x3 prototype 20x20x200mm each 40Samples for R&D and testing, prototype design Electronics, frame15PMT based read-out 0.5 postdoc + 1 student20Labor for simulation and testing Total75 UCLA and other institutions – no additional request at this time

Backup Slides C.Woody, EIC Detector R&D Committee, 6/5/13 26

C.Woody, EIC Detector R&D Committee, 6/5/13 27 Uniformity across the Fiber Ribbon S.Stoll

C.Woody, EIC Detector R&D Committee, 6/5/13 28 sPHENIX EMCAL and HCAL Prototypes HCAL/EMCAL Prototype for beam test at Fermilab this fall sPHENIX Hadron Calorimeter

Sampling Fraction of Accordion Calorimeter C.Woody, EIC Detector R&D Committee, 6/5/13 29 GEANT4 simulation using approximate accordion geometry 5 0 tilt tilt 1.25 cm 0.5 cm 2.4 mm 2.1 mm 1.0 mm W scint F4.0%3.6% Simple answer based on dE/dx (for 0.6 X 0 sampling) Azimuthal dependence of radiation length seen by straight through particle  vs tilt angle (sPHENIX HCAL - flat wedge plates) vs amplitude of oscillation of accordion

C.Woody, EIC Detector R&D Committee, 6/5/13 30 The PANDA PWO Calorimeter Endcap 3864 crystals PWO-II crystals 200 mm long Barrel 15 GeV Positrons R. Novotny

Cost of LSO C.Woody, EIC Detector R&D Committee, 6/5/13 31 From R.-Y. Zhu (Caltech), June 2012