gain monitoring system
DESCRIPTION
Hiroko Ikeda (Kobe Univ.) 6,Aug. 2007 Gakujutusouseikaigi@KEK. Gain Monitoring System. Motivation. To monitor the gain by watching 1 p.e. peak position at BT. LED light has to be distributed to all the strips. LEDs will be controlled by CMB (Calibration Monitoring Board). - PowerPoint PPT PresentationTRANSCRIPT
Gain Monitoring System
Hiroko Ikeda (Kobe Univ.)
6,Aug. 2007
Gakujutusouseikaigi@KEK
Motivation• To monitor the gain by watching 1 p.e. peak
position at BT.
• LED light has to be distributed to all the strips.
• LEDs will be controlled by CMB (Calibration Monitoring Board).
• One CMB can deal with 12 LEDs.
MPPCs(1600 pixels)
Acryl Frame
Scintillator strip(1 x 4.5 x 0.3 cm)
To trigger reflection, put reflective material on strips.
Then, set the acrylic plate covered by the same material on it.
And, shade all from light with black sheet.
ADC
AMP
PC
WLSF
Status・ Signal from flat cable is integrated by ADC,
and number of photons which enter each MPPC is calculated and shown as histograms.
Measurement1• Signal was so small, cut 2mm diameter holes in
reflector sheet on each strip to get bigger signal.
greatly improved but still small
Result11ch 2ch 3ch
4ch 5ch 6ch
9ch8ch7ch
Number of p.e. is calculated as:
20℃
77V
Np.e. = Mean ー ped
d
Measurement2• To increase amount of light, cut tiny hollows on
acrylic plate.
• Due to these holes, reflections thought to occur frequently.
Comparison
▲ : with hollows
● : w/o hollows
Summary• Gain monitoring system in Kobe is running
well.
• Correlation between the distance and amount of light has observed.
• Hollows on acrylic plate increase the amount of light.
Plans• Measure all the channels simultaneously.
• For the BT, much thinner plates and many more photons are needed.
• Try acrylic plate with hollows (all the hollows are exactly the same).