Title: Performance of 10100GeV gamma ray camera for SUBARU opticalinfrared telescope
1Performance of 10-100GeV gamma raycamera for
SUBARU optical-infrared telescope
- A.Asahara, K.Komiyama, G.Kosugi, H.Kubo,
S.Miyazaki, M.Moric, M.Nakagiri, D.Nishida,
R.Ogasawara, - R.Orito, K.Sakurazawa?, T.Takata, T.Tanimori
and T.Usuda
Department of Physics, Kyoto University,
Japan Subaru Telescope, National Astronomical
Observatory cICRR, University Tokyo ?Tokyo
Institute of Technology
AGENDA
- Introduction
- Detectors at GeV region
- High altitude observation
- CheSS gamma ray camera
- Simulation of SUBARU with CheSS
- Observation report
- Summary
21. Introduction -- Pulsars in 10GeV region --
Target Crab pulsar/nebula
- The standard candle for gamma-ray detectors.
- SUBARU has a good location to observe it.
- Wide band pulsed emission
Pass through near the zenith.
Extend above 10GeV ?
Cut off very sharply 20GeV
Cut off more slowly 50GeV
Credit A.K. Harding (NASA/GSFC)
Thompson astro-ph/0101039
32. Detectors in 10GeV region
Crab Nebula (unpulsed component)
Satellite
Ground
Conventional Cherenkov detectors
Over 300GeV
Two new type Cherenkov detectors
One point at 200GeV
One point at 60GeV
43. High Altitude Observation
10GeV gamma-seed (CORSIKA simulation)
5SUBARU optical-infrared telescope
FOV 0.75deg Focal length 15m Mirror
diameter 8.2m Mirror reflectivity 91(380nm) Tra
nsmittance of correction lenses 68(380nm)
PMT array
200mm
0.1deg
0.75deg
6How to set up
PMTs
SUBARU telescope
74.CheSS (Cherenkov light detecting System on
Subaru)
- 44ch VME-TDC (?T 0.75nsec)
- Onboard VME-CPU
- 3ch VME-ADC
- GPS module
Acceptable trigger rate 300Hz (dead time 20)
1m
photo-cathode area 233cm (without light guides)
2
- Weight 200Kg
- Power consumption under 700W
85. Simulation of SUBARU with CheSS
- Night Sky background 6p.e/trigger
- Expected trigger rate0.89 26.7 1.5 30Hz
- Energy threshold (gamma) 30GeV
Jelley(1958)
Same as observation data
Cut the event when the sum of photons is under
7p.e
(Using CORSIKA)
9Sensitivity -- on-off chopping only --
Pulsed
Un-pulsed
106. Observation log
Target Crab pulsar Date 17, 18, and 19,
December 2001 Time on 12hours, off
12hours Weather Fine
3 chopping modes 5min, 10min, and 12min
11Examples of noise reduction
N.S.B
35ns
shower
N.S.B
N.S.B
Camera image
ADC
PMT hit timing (measured by TDC)
12Trigger rate
Data on 17th
Trigger rate of raw data ON 8 - 30Hz OFF 6 -
22Hz
ON
OFF
Trigger rate after ADC cut (over 3000channel)
0.7Hz - 1.7Hz (depends on zenith angle)
137. Summary
- Gamma-ray pulsars in 10GeV region
- Two emission models. polar cap or outer gap?
- Cherenkov light detecting System on SUBARU
- Compact detector. 1m X 1m cylindrical shape, 200
kg weight. - Energy threshold is about 30GeV (simulation).
- Observation of Crab
- On 17, 18, and 19, Dec 2001
- Total time On 12hours and Off 12hours.