Ｇａｉｎ　Ｍｏｎｉｔｏｒｉｎｇ　Ｓｙｓｔｅｍ

28th Feb. 2008

KOBE Hiroko Ikeda

Status• 0.8mm thick, 10mm width,

and flat acrylic plate is considered to be the best.

• Fiber distribution has been done.

• Now trying the system with two layers (twin, as follows)

With only 1 layer

LEDAcrylic plate (27.0cm long)

Fiber Distribution

Clear fiberThere are 20 fibers per a bundle.

LED direction toward each fiber varies.

Amount of LED light greatly depends on the direction.

Compared Np.e. of the ‘closest’ fiber to the light axis with one of the ‘farthest’.

ADC distribution of the ‘closest’ ADC distribution of the ‘farthest’

●:nearest

●:farthest

Vbias:77.0V

LED width:20ns

●:closest

●:farthest12.12%

6.318%

Double Distance (No fiber)2 layers adjoin

Black: Noise (w/o LED) Red: w/ LED Np.e. can be calibrated.

2.853%

Double Distance (with fiber)Closest Farthest

●:Farthest

●:Closest

●:w/o fiber40.68%

24.04%

35.25%

Tracing Paper• In order to reduce the dispersion due to the LED direction,

pinched the tracing paper between LED and fiber.

Tracing paper (40g/m ) 2

●:farthest, w/o tracing paper 35.25%

■:farthest, w/ tracing paper 57.66%

▲:closest, w/o tracing paper 38.50%

▼:farthest, w/ tracing paper 41.43%

Summary & Plans• Np.e. depends on which fiber we use.• Np.e. of the scintilator far from the LED is very small. (Ab

out half of the signal is dark noise. )• There isn’t a significant difference between direct and fib

er in the latter 9cm.• Tracing paper isn’t effective. Need something thicker.

• Determine the number of CMB by this weekend.