s PHENIX EMCAL Conceptual Design C Woody BNL
s. PHENIX EMCAL Conceptual Design C. Woody BNL s. PHENIX Design Study Meeting September 7, 2011
Requirements for the EMCAL • Original Decadal Plan had coverage in the central region over 2 p in azimuth and |h| < 1, plus 2 < h < 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 (Dh ~. 01, Df ~. 01) • Occupancy was thought to be an issue for R=60, RM=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 RM, X 0 and labs, which then determine the transverse segmentation and longitudinal depth • Identifying single photons from p 0 s up to p. T ~ 40 Ge. V/c requires a preshower detector with Dh(Df) ~. 0005 (~ 300 mm at R = 60 cm) • Would like to get sufficient e/p rejection to do J/y and Y physics • At least part of the EMCAL would be inside the magnetic field C. Woody, s. PHENIX Design Study, 9/7/11 2
Decadal Plan C. Woody, s. PHENIX Design Study, 9/7/11 3
s. PHENIX Strawman Revised C. Woody, s. PHENIX Design Study, 9/7/11 4
C. Woody, s. PHENIX Design Study, 9/7/11 M. Perdekamp. RHIC Users Meeting, June 2011 5
Can we reuse the existing PHENIX EMCAL in s. PHENIX ? • 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 (RM ~ 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 ? C. Woody, s. PHENIX Design Study, 9/7/11 6
PHENIX Shashlik EMCAL Dh =0. 01, Df = 0. 01 5. 5 x 5. 5 cm 2 towers at R = 5 m (15, 522 towers total) Alternating stack of lead and scintillator plates 4 towers Module Wavelength shifting fibers pass longitudinally through 36 the. Modules stack Supermodul 18 Supermodules Secto Fibers are bundled in the back and read out with PMTs 6 Sectors RM~ 3 cm Pb (1. 5 mm)Scint (4 mm)66 layers (18 X 0) PMT WLS Light Yield ~ 1. 5 p. e. /Me. V C. Woody, s. PHENIX Design Study, 9/7/11 7
PHENIX Pb. Gl EMCAL TF 1 lead glass (r= 3. 85 g/cm 3, n=1. 648) 9216 blocks 4 x 4 x 40 cm 3 (14. 4 X 0) 24 blocks Module RM~ 4 cm 192 Modules Sector 2 Sectors Light Yield ~ 0. 5 p. e. /Me. V Dominated by photostatistics (no sampling fluctuations) C. Woody, s. PHENIX Design Study, 9/7/11 8
Occupancy Question Revisited Anders back of the envelope calculation implied the occupancy went from 2% in our present EMCAL (RM = 3 cm @ 5 m) to 66% in the new s. PHENIX EMCAL (RM= 2 cm @ Benji Lewis carried out a more detailed simulation 60 cm) with GEANT and found that this was not the case RM ~ 90% containment RM RM C. Woody, s. PHENIX Design Study, 9/7/11 9
Can the EMCAL (alone? ) provide sufficient e/p rejection ? Have been holding regular meetings (organized by Anne Sickles with Tony Frawley and others ) to look at the e/p rejection requirements to do J/ Y and Y physics A. Sickles C. Woody, s. PHENIX Design Study, 9/7/11 10
What e/p rejection is required ? But what about J/Y ‘s with higher p. T ? C. Woody, s. PHENIX Design Study, 9/7/11 Jeff Klatsky (FSU) 11
Possible Designs for the “New” EMCAL for s. PHENIX ? 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 C. Woody, s. PHENIX Design Study, 9/7/11 12
Hybrid Option for PHENIX Central Calorimetry E. Kistenev Si-Sc hybrid option -em energy resolution: 20% at 1 Ge. V -em depth: 20 X 0 or more; -had. Resolution – better 50% at 1 Ge. V -had depth: ~4 Labs -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 Preshower EMC energy sampler Hadronic energy sampler C. Woody, s. PHENIX Design Study, 9/7/11 13
Optical Readout Accordion E. Kistenev Self supporting structure C. Woody, s. PHENIX Design Study, 9/7/11 14
Shashlik W-Sc EMCal Module Moliere Radius RM = 14. 6 mm |h| x |f| 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 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 = 20 X 0 Sampling fraction = 0. 0569 (rapidity independent) Position resolution = 2. 8 mm at E = 1 Ge. V = 0. 9 mm at E = 10 Ge. V b b a a square cross-section “a” slightly decreases from 15. 0 mm to 14. 9 mm as |h| increases “b” slightly decreases from 16. 8 mm to 16. 7 mm as |h| increases C. Woody, s. PHENIX Design Study, 9/7/11 J. Franz 15
Sci-Fi Design Study A. Denisov and V. Bumazhnov (IHEP Protvino) Two types of Scintillator+absorber structures have been simulated: W and Pb absorbers 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 300 mm x 300 mm 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. C. Woody, s. PHENIX Design Study, 9/7/11 16
Summary 1. 2. 3. 4. There are many open questions as to whether or how the present PHENIX EMCAL could be reused in s. PHENIX Occupancy in a new Compact EMCAL as proposed in the original Decadal Plan looks manageable It appears that the calorimeter alone will not provide sufficient e/p rejection for J/y physics (although more studies are needed to settle this) Several possible Compact EMCAL designs are being pursued that can hopefully deliver the performance required C. Woody, s. PHENIX Design Study, 9/7/11 17
Summary of Calorimeter Working Group Discussions 9/8/11 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, e. RHIC) (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 $20 M ? (Ed) Need to include realistic cost estimates in all proposed designs (may exclude some options) C. Woody, s. PHENIX Design Study, 9/7/11 18
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 ? C. Woody, s. PHENIX Design Study, 9/7/11 19
Backup Slides C. Woody, s. PHENIX Design Study, 9/7/11 20
FOCal 2011 Preshower separation -enhanced early shower measurements; -reduced readout gaps to reduce shower p 0 blow-up; g -resolved dynamic range problem. Provides good compactness due to thin sampling layers of silicon Segment - 0 Segment - 1 2 mm W plates, ~5 X 0 Segment - 2 4 mm W plates, ~16 X 0 22 layer of ~500 m Si pads 15 x 15 mm 2 8 layers of ~300 m 0. 5 mm wide Si strips (4 X + 4 Y) C. Woody, s. PHENIX Design Study, 9/7/11 E. Kistenev 21
Technology Choices • Sampling vs Homogeneous Reduced by sampling fraction “Apparent” RM ~ 1. 8 cm due to Cherenkov • Optical vs Ionization - Optical Scintillator (crystal, plastic), Wavelength Shifter, C - Ionization Silicon, Noble Liquids (Ar, Kr, Xe) • Readout Devices C. Woody, s. PHENIX Design Study, 9/7/11 22
Pb-Sci-WLS Accordion (E. Kistenev and colleagues from IHEP circa ~2005) C. Woody, s. PHENIX Design Study, 9/7/11 23
- Slides: 23