Current status for FRP dark measurement

1
Current status for FRP dark measurement
22nd Jun. 2005 T.Sato

• PMT dark rate
• FRP BG included PMT dark rate
• Current status (Na lamp)
• Summary

2
PMT dark rate
Before 1st measurement of the 2002 FRP exposure
to Na lamp
7kHz
Before 2nd measurement of the 2002 FRP exposure
to Na lamp
Before 1st measurement of the 2005 FRP exposure
to Na lamp
6.5kHz
3
FRP BG included PMT dark rate
2002 FRP BG 10kHz
2005 FRP
Excess 33.5kHz
2005 FRP BG 3035kHz
Excess 23.524kHz
2002 FRP
It might have rising trend for 2005 FRP BG .
4
Current status I
2005 FRP
Excess from PMT dark
Raw data
2002 FRP
6.5kHz subtracted
6.5kHz subtracted
PMT dark
7.0kHz subtracted
2005 FRP measurement is continued now !
5
Current status II
2005 FRP
Excess from FRP BG PMT dark
Raw data
32.5kHz subtracted
FRP BG (2005) PMT dark
FRP BG (2002) PMT dark
2002 FRP
10.0kHz subtracted
6
Current status III
32.5kHz subtracted case
35.0kHz subtracted case
4kHz
3kHz
2kHz
It has about 4kHz remaining to reach FPR BG PMT
dark level.
It has about 1kHz remaining to reach FPR BG PMT
dark level.
7
Summary

• There has been a excess from FRP BG PMT dark
  yet.
• 2005 FRP data is strange in recent days.
• We must check the electronics, because it may
  have trouble.