R&D on W-SciFi Calorimeters for EIC at Brookhaven E.Kistenev, S.Stoll, A.Sukhanov, C.Woody PHENIX Group E.Aschenauer and S.Fazio Spin and EIC Group Physics Department Brookhaven National Lab EIC Detector R&D Committee Meeting May 17, 2012

Connection with other R&D Efforts at BNL on Calorimetry for EIC C.Woody, EIC Detector R&D Committee, 5/17/12 2 The PHENIX Collaboration is currently pursuing a major new upgrade effort → sPHENIX Main physics goal is to measure jets in heavy ion collisions Includes two new calorimeter systems  Hadronic (first in any experiment at RHIC)  Electromagnetic (W-SciFi accordion) R&D on calorimetry in general is an area of overlap with future interests at EIC, but primarily focus now is on an EMCAL Propose to combine parts of these efforts which would be of specific interest to EIC and not part of the PHENIX R&D plan into this proposal, along with simulation efforts on calorimetry for EIC from the BNL SPIN/EIC Group

C.Woody, EIC Detector R&D Committee, 5/17/12 3 HCAL Outer HCAL Inner EMCAL Solenoid VTX Coverage ± 1.1 in  and 2  in  EMCAL: R inner =95 cm, T ~ 10 cm, L = 2.8m

sPHENIX EMCAL Requirements C.Woody, EIC Detector R&D Committee, 5/17/12 4  E/E ~ 18%/√E (~ 1 X 0 sampling) - want much better resolution for EIC Need high segmentation for central heavy ion collisions - not as strong a requirement for EIC Energy range up to ~ 50 GeV in the central region for jets - may be similar for EIC, although generally lower E Must be compact (small Moliere radius, short radiation length) - small size  low cost Tungsten scintillating fiber accordion satisfies these requirements - new technologies with tungsten materials makes this possible Readout must work inside a magnetic field - silicon photomultipliers are the preferred option

Optical Accordion Calorimeter 5 Accordion design similar to ATLAS Liquid Argon Calorimeter Volume increases with radius Scintillator thickness doesn’t increase with radius, so either tungsten thickness must increase or the amplitude of the oscillation must increase, or both Plate thickness cannot be totally uniform due to the undulations Small amplitude oscillations minimize both of these problems Want to be projective in both r-  and  C.Woody, EIC Detector R&D Committee, 5/17/12

Sintered Tungsten Plates 6 Variable thickness W-plates Scintillating fibers in between Density  ~ 17.5 g/cm 3 Problem is that cannot make sintered plates larger than ~ 20 cm Phase I SBIR with 20 cm C.Woody, EIC Detector R&D Committee, 5/17/12

Tungsten SciFi Epoxy Sandwich 7 Scintillating fibers ~ 0.5 – 1.0 mm Pure tungsten metal sheet (  ~ 19.3 g/cm 3 ) Thickness ~ mm Tungsten powder epoxy (  ~ g/cm 3 ) Uniform thickness, thin pure tungsten metal sheets with wedge shaped SciFi + tungsten powder epoxy layer in between Can be made into larger modules (> 1m) C.Woody, EIC Detector R&D Committee, 5/17/12

Readout and Light Yield 8 Want to have small photostatistics contribution to the energy resolution Need sufficient light output from fibers to allow randomizing and collecting the light onto a small readout device SiPM Scintillating Fibers Small reflecting cavity or wavelength shifting block Possible Readout Schemes C.Woody, EIC Detector R&D Committee, 5/17/12 SiPM direct readout of scintillating tile with “dimple” F.Simon & C.Soldner, NIM A620(2010) Light output from fibers ~ 100 p.e./MeV Consistent with UCLA beam test measurement

Readout Devices & Electronics 9 C.Woody, EIC Detector R&D Committee, 5/17/12 Considering two types of readout devices: SiPMs and APDs SiPMs Higher gain (~10 6 ) High noise (~ few MHz/mm 2 at ~ 1 p.e. level) Sensitive to temperature and voltage G ~ (V op -V br ), V br varies with T (~50 mV/°C  dG/dT ~ 10% /°C) Limitation on dynamic range due to finite number of pixels Need to “tune” light level to stay within “linear” range New SiPMs being developed (AdvanSiD, Zecoteck,…) with more pixels/mm 2 and (hopefully) high PDE APDs Gain ~ Better linearity dG/dV ~ 3%/V, dG/dT ~ 2% /°C Hamamatsu S C 3x3 mm K 25  m pixels Readout electronics must be designed to match SiPM – high gain  don’t need ultra low noise electronics (currently being developed within PHENIX) APD – requires higher gain, lower noise front end Both will require temperature stabilization and gain monitoring

R&D Goals for this Proposal 10 Develop W-SciFi technology that would allow building a high resolution electromagnetic calorimeter that is specifically optimized for EIC. Utilize parts of the R&D program within the PHENIX Collaboration, which is exploring similar technologies for sPHENIX, to leverage the effort on this design Note: The R&D for EIC would focus only on work that would not be done within the context of the PHENIX effort. Study techniques to build modules with finer sampling and/or higher sampling fraction using the layered sandwich technique that would achieve the best possible energy resolution Study readout schemes to optimize the light levels for different readout devices (SiPMs and APDs) that would be most suitable in terms of gain, linearity and dynamic range for the energy range at EIC Develop the readout electronics that would best match the calorimeter design and readout scheme that would be optimized for EIC Generate simulation results to provide feedback and guidance on the calorimeter design C.Woody, EIC Detector R&D Committee, 5/17/12

R&D Plan 11 Year 1 Study and develop a high resolution EMCAL module design using the layered sandwich technique that is optimized for EIC applications 1.Fabricate and test module layers with finer sampling and/or higher sampling fraction (e.g., using thinner tungsten plates, smaller diameter fibers, etc.) 2.Study methods for embedding fibers that allow projective module construction 3.Study light collection and mixing schemes that allow the use of either a single or limited number of readout devices which provide sufficient photostatistics 4.Develop the readout electronics to read out the device(s) used with the light mixer(s) 5.Build several high resolution modules using the optimized designs from (1-4) Year 2 Construct one or more full scale prototype modules with a high resolution design and fully characterize them in a test beam Modules ~ 20 x 20 cm 2 x 10 cm deep (10 x 10 towers) Build readout electronics for prototype modules Carry out beam tests in collaboration with the UCLA/TAMU/PSU group C.Woody, EIC Detector R&D Committee, 5/17/12 Simulation results and feedback are provided throughout years 1 and 2

Budget 12 Note: Funding request is for items that would not be covered as part of the PHENIX R&D effort or the SBIR with Tungsten Heavy Powder C.Woody, EIC Detector R&D Committee, 5/17/12