PMT ScreeningPreshipping calibration

1
PMT Screening/Pre-shipping calibration

• July-August batch summary
• Shigeru Yoshida (Chiba)

IceCube Collab. meeting 2004
2
12 tubes monthly from Hamamatsu

• Fundamental measurements
• -- Charge Resolution
• -- P/V
• -- Gain HV scan
• -- Dark count
• CE mapping
• Gain mapping

3
PMT Setting in the Freezer
Base circuit
Diffuser attached to UV LED
4
Setup
LinuxPC
CAMAC
GP-IB
PCI Card
Crate Controller
Function Generator
CAMAC Interface
ADC
GP-IB Interface
Sync.
Signal
NIM
50nsec
Gate
Amp (10)
Freezer(-32?)
Discriminator
Gate Generator
UV LED
PMT
Scaler
Gate Generator
TTL-NIM Converter
5
Charge Response
6
Charge Resolution
7
P/V
2.7
8
Gain HV scanJuly 2004
9
Gain HV scanAugust 2004
Next Month Get rid of 50 W - the bare PMT gain
10
Dark Count (0.3 pe threshold)
11
Dark Count (Contd)

• Our measurements _at_ gain 5x107
• Operation Gain 1x107
• Measurements by GPIB-based digital scope
• rate _at_ 1x107 0.8 x rate _at_ 5x107
• Still a way above 500Hz.

12
Position dependence of gain
13
Position dependence of gain (Contd)
Taken into account by the Detector MC (ROMEO)
14
Position dependence of CE
A representative Response has been implemented In
the detector MC
15
Setup
ATTENUATOR
Pressure meter
Temp monitor
16
Absolute calibration of PMT efficiency
SF0077, SF0050, SF0061
Hirokos talk at the instrumentation WG
17
Conclusion

• Gain, P/V, charge resolution in good shape
• 2 dimensional gain and CE map taken for the
  detector MC
• Absolute QE-CE calibration works fine
• Dark count higher than 500 Hz

Future outlook

• HV _at_ gain 107 is determined carefully
• DOM angular response
• DOM absolute calibration