1. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop1 Boris Khachaturov, Alexander Kozlov, Ilia Ravinovich and Itzhak Tserruya Weizmann Institute, Israel Mini Workshop on PHENIX upgrade plans, BNL Aug. 5-6, 2002 HBD R&D at the WIS

2. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop2Outline The HBD concept Goals of the R&D programme at the WI Set-up and Status Plans

3. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop3 HBD in PHENIX HBD Compensate magnetic field with inner coil (B=0 for r 50-60cm) Compact HBD in the inner region Specifications * Electron efficiency 90% * Modest  rejection ~ 200 * Double hit recognition 90%

4. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop4 Detector Configuration Transmissive CsI photocathode No photon feedback Concept: Windowless Cherenkov detector Radiator and detector gas: CF 4 Large bandwidth and large N pe

5. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop5 CsI photocathode QE Transmissive photocathode – Relatively high quantum efficiency The most attractive option: Very large bandwidth: 6 – 11.5 eV Very large N 0  940: 40 pe in a 50cm radiator

6. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop6 Detector Configuration Detector element: multi - GEM High gain Novel Concept: Windowless Cherenkov detector Radiator and detector gas: CF 4 Large bandwidth and large N pe Transmissive CsI photocathode No photon feedback No ring image as in RICH or in proximity focus  blob image Low granularity

7. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop7 Pads – Shape: hexagonal – Dimension: app. size of the blob (R=1.8cm) –  2000 pads to cover central arm acceptance – Threshold: defined by background Detector configuration: granularity

8. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop8 Main Goals of the R&D Programme Demonstrate concept validity * Response to electrons and hadrons (N pe per electron and per mip) * CF 4 scintillation * Demonstrate e-efficiency and double hit recognition.

9. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop9 CF 4 radiator gas / Alternative C 4 F 10 ? CF 4 scintillation parameters: – Peak at 163nm – 100-200 photons/MeV and dE/dx = 7keV/cm – 20-30% CsI Q.E.. Results: – 0.007 ph/(MIP cm 2 ) – 250 MIPs in one PHENIX arm – 10 cm 2 size of the blob Signal / noise > 10! Shades reduce noise by a factor of 3 Timing ? CF 4 scintillation is not a killing factor

10. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop10 Main Goals of the R&D Programme Generic Detector R&D * CsI / CF 4 bandwidth * Gain in GEM * Aging of CsI and GEM in CF 4 * Optimize Detector configuration: 3 GEM or 2GEM + MWPC? * dE/dx in CF 4 Monte Carlo simulations Demonstrate concept validity * Response to electrons and hadrons (N pe per electron and per mip) * CF 4 scintillation * Demonstrate e-efficiency and double hit recognition.

11. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop11 Cosmic ray signals in Ar/CO 2 Ar/CO 2 70-30 –  V GEM = 450 V – E d = 2.0 kV cm –1 – E t = 4.0 kV cm –1 – E i = 4.5 kV cm –1 Gain: 4 x 10 4 S. Bachman et al. NIM 438A (1999) 376 Mounting & working with GEM

12. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop12 CF 4 + GEM + CsI work!

13. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop13 Setup: from the original sketch (end 2001)… Cherenkov counter for high momentum muons (~min -1 ) Set up:  Detector: double GEM (10x10cm 2 ) + PCB  Cosmic trigger: 3 layer plastic scintillators + Cherenkov counter (in near future) Electric scheme  Two HV power supplies for more flexibility  Cathode readout

14. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop14 Setup: …to a more elaborated sketch (1.2002) … Design almost complete Manufacturing and order underway

15. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop15 Setup: … to the full design (2.2002) … Cherenkov cosmic ray trigger Cherenkov light reflected by 16 mirrors, in a pyramid arrangement, onto 4 large PM Mini HBD: CF 4 radiator tank + Multi –Gem detector box Scintillators

16. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop16 Setup: … to real life (7.28.02) Cherenkov cosmic ray trigger Cherenkov light reflected by 16 mirrors in a pyramid arrangement onto 4 large PM Mini HBD: CF 4 radiator tank + Multi –Gem detector box Scintillators

17. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop17 The mirror support

18. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop18 The mirrors mounted

19. 6-Aug-02Itzhak Tserruya PHENIX Upgrade mini-Workshop19 Status & plans: Basic equipment to work with GEM is ready: – UV source, x-ray and alpha sources – Electronics, gas system, monochromator Double GEM detector is working at the WIS in Ar/CO 2 – Gain 4.5·10 4 achieved and is consistent with measured at CERN – CsI photocathodes routinely produced with reproducible results – Moving to CF 4 within the next weeks. Cosmic ray trigger – Procurement of parts and components completed (only CF 4 radiator tank is missing) – Setting-up underway Mini HBD – Procurement of parts and components almost completed (only CF 4 radiator tank is missing) – Multi-GEM box ready. Simulations – Optimize shade configuration to absorb scintillation – Granularity