1. C.Woody BNL sPHENIX EMCAL Conceptual Design sPHENIX Design Study Meeting September 7, 2011

2. C.Woody, sPHENIX Design Study, 9/7/112 Requirements for the EMCAL Original Decadal Plan had coverage in the central region over 2  in azimuth and |  | < 1, plus 2 <  < 4 in the forward direction (one side) Calorimeter needed to be hermetic and projective To handle shower overlaps in central Au+Au collisions required - Small Moliere radius (~ 2 cm) - High segmentation (  ~.01,  ~.01) Occupancy was thought to be an issue for R=60, R M =2 cm (Anders calc) Energy resolution ~ 15%/  E The energy resolution requirements will determine the sampling fraction, which will in turn have an impact on R M, X 0 and abs, which then determine the transverse segmentation and longitudinal depth Identifying single photons from  0 s up to p T ~ 40 GeV/c requires a preshower detector with  (  ) ~.0005 (~ 300  m at R = 60 cm) Would like to get sufficient e/  rejection to do J/  and Y physics At least part of the EMCAL would be inside the magnetic field

3. C.Woody, sPHENIX Design Study, 9/7/113 Decadal Plan

4. C.Woody, sPHENIX Design Study, 9/7/114 sPHENIX Strawman Revised

5. C.Woody, sPHENIX Design Study, 9/7/115 M.Perdekamp. RHIC Users Meeting, June 2011

6. C.Woody, sPHENIX Design Study, 9/7/116 Can we reuse the existing PHENIX EMCAL in sPHENIX ? How would the present detector modules be reconfigured to cover the desired rapidity range ? Could any part of it be used in the forward direction ? (high rapidity density, short radiation length, radiation damage ? ) Non projective, not hermetic Large Moliere radius (R M ~ 3-4 cm) Will the PMTs work in the high fringe field of the new open solenoid or other magnetic field configuration ? We would probably want new electronics and a new HV system if we were going to reuse it for another 10 years How would the presence of the PMTs, HV and readout electronics affect the HCAL behind it ? What would be the cost of reconfiguring part of the existing EMCAL versus mounting a new one ?

7. C.Woody, sPHENIX Design Study, 9/7/117 PHENIX Shashlik EMCAL  =0.01,  = 0.01  5.5 x 5.5 cm 2 towers at R = 5m (15,522 towers total) Alternating stack of lead and scintillator plates Wavelength shifting fibers pass longitudinally through the stack Fibers are bundled in the back and read out with PMTs Light Yield ~ 1.5 p.e./MeV PMT WLS Pb (1.5 mm)Scint (4 mm) 66 layers (18 X 0 ) 4 towers  Module 36 Modules  Supermodule 18 Supermodules  Sector 6 Sectors R M ~ 3 cm

8. C.Woody, sPHENIX Design Study, 9/7/118 PHENIX PbGl EMCAL Light Yield ~ 0.5 p.e./MeV TF1 lead glass (  = 3.85 g/cm 3, n=1.648) 9216 blocks 4x4x40 cm 3 (14.4 X 0 ) R M ~ 4 cm Dominated by photostatistics (no sampling fluctuations) 24 blocks  Module 192 Modules  Sector 2 Sectors

9. C.Woody, sPHENIX Design Study, 9/7/119 Occupancy Question Revisited Anders back of the envelope calculation implied the occupancy went from 2% in our present EMCAL (R M = 3 cm @ 5 m) to 66% in the new sPHENIX EMCAL (R M = 2 cm @ 60 cm) Benji Lewis carried out a more detailed simulation with GEANT and found that this was not the case R M ~ 90% containment RMRM RMRM

10. C.Woody, sPHENIX Design Study, 9/7/1110 Can the EMCAL (alone?) provide sufficient e/  rejection ? Have been holding regular meetings (organized by Anne Sickles with Tony Frawley and others ) to look at the e/  rejection requirements to do J/  and Y physics A. Sickles

11. C.Woody, sPHENIX Design Study, 9/7/1111 What e/  rejection is required ? Jeff Klatsky (FSU) But what about J/  ‘s with higher p T ?

12. C.Woody, sPHENIX Design Study, 9/7/1112 Possible Designs for the “New” EMCAL for sPHENIX ? Requirements: Compact (“small” Moliere radius and “short” radiation length) Projective Hermetic Readout works in a magnetic field Low cost Options: Optical accordion Projective shashlik Scintillating fiber Any design must include a (presumably) tungsten-silicon preshower which would sit inside the magnet

13. C.Woody, sPHENIX Design Study, 9/7/1113 Hybrid Option for PHENIX Central Calorimetry -em energy resolution: 20% at 1 GeV -em depth: 20 X0 or more; -had. Resolution – better 50% at 1 GeV -had depth: ~4 Labs Si-Sc hybrid option -Active preshower ~4 X 0 -2 mm W (or equivalent) plates in preshower -Si readout in preshower -Pb & Sc in both E-sampling segments -Optical readout in sampling segments s-c magnet EMC energy sampler Hadronic energy sampler Preshower E.Kistenev

14. C.Woody, sPHENIX Design Study, 9/7/1114 Self supporting structure Optical Readout Accordion E.Kistenev

15. C.Woody, sPHENIX Design Study, 9/7/1115 Shashlik W-Sc EMCal Module square cross-section “a” slightly decreases from 15.0 mm to 14.9 mm as |  | increases “b” slightly decreases from 16.8 mm to 16.7 mm as |  | increases a a b b Thickness of W = 1.5 mm Thickness of Scintillator = 1.0 mm Radiation length X 0 = 5.8 mm use 46 layers of W+Sc Depth of the module = 20X 0 Sampling fraction = 0.0569 (rapidity independent) Position resolution = 2.8 mm at E = 1 GeV = 0.9 mm at E = 10 GeV Moliere Radius R M = 14.6 mm |  | x |  | segmentation = 0.0146 x 0.0146 (Projective) ~50 K Channels Don’t Need Preshower/SMD ? Energy resolution = 11.3 % / sqrt(E) Occupancy: 20 % (same assumptions for Pb) Price Quote: $8.2 M Total weight: 17.6 ton J.Franz

16. C.Woody, sPHENIX Design Study, 9/7/1116 Sci-Fi Design Study A.Denisov and V.Bumazhnov (IHEP Protvino) Two types of Scintillator+absorber structures have been simulated: 1) “spaghetti” with maximal geometrical sampling uniformity (left figure); 2)”slice” type for simplest mechanical treatment (right figure); Simulations have been performed for calorimeter modules with cross-section of 300mm x 300mm and length of absorber of 200 mm(along of electron beam). The volume scintillator/absorber ratio is of about 30% for both cases. Geometry modification to take into account projective geometry requirements has not been implemented in this simulation yet. We believe that this effect should be small enough. W and Pb absorbers

17. C.Woody, sPHENIX Design Study, 9/7/1117 Summary 1.There are many open questions as to whether or how the present PHENIX EMCAL could be reused in sPHENIX 2.Occupancy in a new Compact EMCAL as proposed in the original Decadal Plan looks manageable 3.It appears that the calorimeter alone will not provide sufficient e/p rejection for J/  physics (although more studies are needed to settle this) 4.Several possible Compact EMCAL designs are being pursued that can hopefully deliver the performance required

18. C.Woody, sPHENIX Design Study, 9/7/1118 Present - Andrei Sukhanov, Sean Stoll, Benji Lewis, Takao Sakaguchi, Anne Sickles, Rich Seto, Dimitri Kotchetkov, Chris Pinkenburg, Craig Woody, Bob Azmoun Questions and issues to be addressed over the next 1-6 months: 1)What is the radius of the magnet ? Will there be some other field configuration in the forward direction ? This will drive the mechanical design of the EMC and HCAL 2) What resolution and segmentation do we really need for the EMCAL ? Physics input and supporting plots (Anne); detector design (Craig) 3) What should be the optimum thickness and segmentation of the Preshower (Rich) 4) What resolution is really required for the HCAL ? What is the driver? (heavy ions, pp, eRHIC) (Matthias Brian, Rich) 5) If we go to higher field, is there a dispersion between the neutral and charged components of the shower that could affect our jet measurement ? (Brian) 6) Need to include areas for support, infrastructure and service in the current design. Is integration cost included in the $20M ? (Ed) Need to include realistic cost estimates in all proposed designs (may exclude some options) Summary of Calorimeter Working Group Discussions 9/8/11

19. C.Woody, sPHENIX Design Study, 9/7/1119 7) Need more contact and discussion with other groups who have recently built or are planning to build large calorimeters (CMS, ATLAS, JLAB, ILC…). New collaborators ? 8) Monte Carlo Studies (Chris) Study the effect of dead material on energy resolution, uniformity, etc. A) Preshower+EMCAL inside magnet, HCAL outside magnet B) Preshower inside magnet, EMCAL outside,then support stucture for HCAL, then HCAL C) Can we use the magnet coil as the first part (~ 1 Xo) of the Preshower ? 9) Need to develop a simple simulation for the accordion design (Edward ?) 10) How do we make a projective, hermetic, longitudially segmented calorimeter (Craig, Dmitri ) 11) Given the recent results on e/pi separation (implying we need some other detector to identify electrons), can we give up longitudinal segmentation of the EMCAL, and if so, how would it affect jet measurements ? (Anne, Craig, Marzia, Tony, Jeff K.) 12) Could we do muon physics on the north side with an HCAL plus additional tracking and leaving the Mu-ID ? (i.e., can we flip our forward detector to the north side, leaving the south side free to built a electron spectrometer for e-RHIC ?

20. C.Woody, sPHENIX Design Study, 9/7/1120 Backup Slides

21. C.Woody, sPHENIX Design Study, 9/7/1121 FOCal 2011 2 mm W plates, ~5 X0 4 mm W plates, ~16 X0 22 layer of ~500  Si pads 15x15 mm 2 8 layers of ~300  0.5 mm wide Si strips (4 X + 4 Y) Segment - 0Segment - 1Segment - 2 -enhanced early shower measurements; -reduced readout gaps to reduce shower blow-up; -resolved dynamic range problem. E.Kistenev 00  Preshower separation Provides good compactness due to thin sampling layers of silicon

22. C.Woody, sPHENIX Design Study, 9/7/1122 Technology Choices Sampling vs Homogeneous Optical vs Ionization - Optical  Scintillator (crystal, plastic), Wavelength Shifter, Cherenkov - Ionization  Silicon, Noble Liquids (Ar, Kr, Xe) Readout Devices “Apparent” R M ~ 1.8 cm due to Cherenkov Reduced by sampling fraction

23. C.Woody, sPHENIX Design Study, 9/7/1123 Pb-Sci-WLS Accordion (E. Kistenev and colleagues from IHEP circa ~2005)