Hybrid PMT Tests & Geometry

Zisis PapandreouDetector Interface MeetingBloomington, IndianaNovember 1st, 2001

BCAL Dimensions (CDR)

o Length: 4 mo Outer Radius: 90 cm

o Thickness: 20-25 cm (~16X0)

o Pb Radiation Length: 1X0 = 0.56 cm

No. of modules: 48 (96 phi slices)No. of PMTs: 12 x 48 = 576

BCAL 96 Phi/Readout Slices

1st face width 4.25 cm

2nd face width 4.80 cm

3rd face width 5.35 cm

4th face width 5.90 cm

HPMT outer diameterHPMT active diameter

5.60 cm2.55 cm

Each PhiSegment side

Total Area210 cm2

Area Reduction

4:1

HPMT Area5 cm2

No of HPMTs10

HPMT Old Geometry (6 PMTs)

5.90 cm

5.35 cm

4.80 cm

4.25 cm HPMT

Staggered HPMTs

DEP-PP0350G 5.60 cm outer diameter 2.55 cm active diameter

Al plate 2.5 cm

A tight squeeze!

KLOE Winston Cones – Module-0

HPMT New Geometry (10 PMTs)?

Staggered HPMTs

DEP-PP0350G 5.60 cm outer diameter 2.55 cm active diameter

4.25 cm

HPMT

Al plate 2.5 cm

5.90 cm

4.80 cm

5.35 cm

Tough-cookie design!Solution:

DEP redesigns theelectronics housing

What’s a Hybrid?

Proximity-focused vacuum tubeFast rise- and fall-time (2, 12 ns)High QE for UV, Gain is 105

Insensitive to high magnetic fields

Fused silica window

HV: -8kVBias: -80VPre-ampShaper

HPMT Electronic Circuit

The real McCoy…

DEP PP0350G

DEP PP0100Z

UofR HV regulator

Up close and personal

HPMT UofR Housing

Preliminary HPMT tests

Discharging problem: partly solvedPre-amp selection: solvedSignals observed from radioactivity source using a NaI detectorDirect communication with DEP establishedPersonnel: Electronics engineer, technician, postdoc

(Vitaly Kovaltchouk)

Regina “Flasher”

Was recently apprehended. Replacement: Optitron Xe-N Flasher System 200 psi 20 kV across the electrodes Pulse resembles scintillator pulse Externally triggered, frequency

controlled, or single flash modes

Flasher Tube

Flasher Test Setup

Zooming in…

HPMT Testing Chores

Need to perfect the electronic circuit Fast charge pre-amp Suitable pulse shaper HV-rated cables

Communicate with DEP Modify the detector design Transfer knowledge

Bench tests Operate with Flasher Operate with Cosmic Rays

HPMT Geometry List

Optimize area reduction (4:1)Light guides and Winston ConesHPMTs must be staggered for clearanceNo. of HPMTs must be settledGUIDEIT MC simulations requiredGood neighbor policy: Solenoid Drift chambers