PMT Status

1
A first look of the 10 High QE PMT
Super Bialkali photocathode
Shigeru Yoshida for Yuusuke Hasegawa and Mina
Inaba Dep. of Physics, Chiba University
2
Which is which?
Our IceCube PMT
Super Bialkali PMT
The Graduate Student
3
Photocathode calibration
QECE Absolute calibration
Reference PMT Absolutely calibrated
PMT
X-stage
LED
DOM
motor
LED
Slit 1mm
NDfilter
Reflectivity 14.50.73 Transmission
50.72.54
Systematic error 7 _at_ room
4
Absolute QECE
IceCube PMT
IceCube PMT
5
Averaged PMT2D CEMap(94PMTs)
PMT 2D Uniformity Scan
The direction of the first dynode
6
2D QE x CE Map of PMT
_at_337nm
Systematic error 8
TA1895
TA2026
TA2259
TA2349
20 0
-0.15m 0.15m
18.1
15.5
15.0
16.7
TA2086
TA2146
TA2182
TA2374
17.8
16.0
18.7
17.9
7
The Test bench
CAMAC
GP-IB
PCI Card
Crate Controller
Function Generator
CAMAC Interface
ADC
GP-IB Interface
Sync.
LinuxPC
70nsec
Gate
100ns
Freezer(-35?)
Signal
375 nm UV LED
46nsec
PMT
NIM
Gate Generator
Discriminator
diffuser
2kHz, 0.01 photo-electron/shot
TTL-NIM Converter
8
The Test Bench
Diffuser attached to the UV LED
In the Freezer box
Freezer -35?
375nm UV LED
2kHz, 0.01 photo-electron/shot
9
HV dependence of the PMT gain
Super PMT
Gain (x107)
107 Gain
10
SPE Charge Historgram
_at_5x107 -35C
Our IceCube PMT
Super Bialkali PMT
pedestal
SPE
11
P/V
-35C
Super PMT
Peak/Valley
Gain (x107)
12
Charge Resolution
-35C
Super PMT
sq/q0
30 line
Gain (x107)
13
The IceCube PMT charge response
One measurement
Peak of gaussian 1 p.e.
Charge resolution 29
Average over 118 PMTs
Mean 15 less
14
Now Super PMT case
One measurement
Average over 118 PMTs
15
Dark Rate
Discri. threshold 0.25 p.e.
Super PMT
Dark Rate Hz
1kHz
Temperature C
16
Summary

• QE 35 _at_ 365 nm (IceCube PMT 25)
• Charge response, cathode uniformity comparable
  with the IceCube PMTs
• P/V is even better.
• Dark Rate 1kHz _at_ -35 C
• (IceCube PMT 600Hz)

17

• Backup slides

18
Absolute QE
QE measured at -32? tend to 510 lower than
measured at 24? However, they agree within the
systematic error.
Keno_Inuzaka(TA1056)
Daikaku_Inumura(TA1176)
Sosuke_Inukawa(TA1181)
15.0 12.5
13.2 14.2
16.4 15.4
10.6 9.70
16.6 15.7
11.3 10.4
9.14 8.93
18.3 16.3
16.0 13.3
4.69 4.30
4.23 3.74
4.88 3.96
Red measured at 24? Blue measured at -32?