6-aug-02itzhak tserruya phenix upgrade mini-workshop1 boris khachaturov, alexander kozlov, ilia...

6-Aug-02 Itzhak Tserruya PHENIX Upgrade mini-Workshop

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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 WISHBD R&D at the WIS


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OutlineOutline

The HBD concept

Goals of the R&D programme at the WI

Set-up and Status

Plans


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HBD in PHENIX

HBD

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%


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Detector ConfigurationDetector Configuration

•Transmissive CsI photocathode

No photon feedback

Concept:

• Windowless Cherenkov detector

• Radiator and detector gas: CF4

Large bandwidth and large Npe


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CsI photocathode QECsI photocathode QE

Transmissive photocathode

Relatively high quantum efficiency

The most attractive option:

Very large bandwidth:

6 – 11.5 eV

Very large N0 940:

40 pe in a 50cm radiator


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Detector ConfigurationDetector Configuration

•Detector element: multi - GEM

High gain

Novel Concept:

• Windowless Cherenkov detector

• Radiator and detector gas: CF4

Large bandwidth and large Npe

•Transmissive CsI photocathode

No photon feedback

• No ring image as in RICH or in

proximity focus blob image

Low granularity


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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: granularityDetector configuration: granularity


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Main Goals of the R&D Programme • Demonstrate concept validity

* Response to electrons and hadrons (Npe per electron and per mip)

* CF4 scintillation

* Demonstrate e-efficiency and double hit recognition.


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CFCF44 radiator gas / radiator gas / Alternative CAlternative C44FF10 10 ??CF4 scintillation parameters:

Peak at 163nm

100-200 photons/MeV and dE/dx = 7keV/cm

20-30% CsI Q.E..

Results: 0.007 ph/(MIP cm2)

250 MIPs in one PHENIX arm

10 cm2 size of the blob

Signal / noise > 10!

Shades reduce noise by a factor of 3

Timing ?

CF4 scintillation is not a killing factor


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Main Goals of the R&D Programme

• Generic Detector R&D

* CsI / CF4 bandwidth

* Gain in GEM

* Aging of CsI and GEM in CF4

* Optimize Detector configuration: 3 GEM or 2GEM + MWPC?

* dE/dx in CF4

• Monte Carlo simulations

• Demonstrate concept validity

* Response to electrons and hadrons (Npe per electron and per mip)

* CF4 scintillation

* Demonstrate e-efficiency and double hit recognition.


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Cosmic ray signals in Ar/COCosmic ray signals in Ar/CO22

Ar/CO2 70-30

VGEM = 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 104

S. Bachman et al. NIM 438A (1999) 376S. Bachman et al. NIM 438A (1999) 376S. Bachman et al. NIM 438A (1999) 376S. Bachman et al. NIM 438A (1999) 376S. Bachman et al. NIM 438A (1999) 376S. Bachman et al. NIM 438A (1999) 376

Mounting & working with GEM


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CFCF4 4 + + GEM + CsI work!GEM + CsI work!


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Setup: from the original sketch (end 2001)…Setup: from the original sketch (end 2001)…

Cherenkov counter for high momentum muons

(~min-1)

Set up: Detector: double GEM (10x10cm2) + PCB Cosmic trigger: 3 layer plastic scintillators +

Cherenkov counter (in near future)

Electric scheme Two HV power supplies for more flexibility Cathode readout


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Setup:Setup: …to a more elaborated sketch (1.2002) … …to a more elaborated sketch (1.2002) …

• Design almost complete• Manufacturing and order underway


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Setup: … to the full design (2.2002) …Setup: … to the full design (2.2002) …

Cherenkov cosmic ray trigger

Cherenkov light reflected by16 mirrors, in a pyramidarrangement, onto 4 large PM

Mini HBD: CF4 radiator tank + Multi –Gem detector box

Scintillators


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Setup: … to real life (7.28.02)

Cherenkov cosmic ray trigger

Cherenkov light reflected by16 mirrors in a pyramidarrangement onto 4 large PM Mini HBD: CF4 radiator tank + Multi –Gem detector box

Scintillators


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The mirror support


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The mirrors mounted


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Status & plans: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/CO2

Gain 4.5·104 achieved and is consistent with measured at CERN

CsI photocathodes routinely produced with reproducible results

Moving to CF4 within the next weeks.

Cosmic ray trigger Procurement of parts and components completed (only CF4 radiator tank is missing)

Setting-up underway

Mini HBD Procurement of parts and components almost completed (only CF4 radiator tank is missing)

Multi-GEM box ready.

Simulations Optimize shade configuration to absorb scintillation

Granularity

6-aug-02itzhak tserruya phenix upgrade mini-workshop1 boris khachaturov, alexander kozlov, ilia...

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