Some Remarks on Calibration of BCAL.

After recent communications with the BCAL team, seems that we have to use a 2 wire cable, 5-10 cm, from the board so as only the LED is attached on the light guide.

I made some tests and I didn’t measure any deterioration of the signal.

Do we need an extension with the trapezoidal L-Gs?

Pending issues.

Position and support of the board. Piggy-back on the Amplifier board.Any other suggestion from the engineers.

Protocol:Any 2-wire protocol.Serial Xon/Xoff as requested.

Intensity and Dynamic Range. Intensity can be Controlled by:

Dc Voltage Adjustment.A piece of Film Filter between LED and the Light

Guide. Range:

Using an LED with Longer Wavelength, Below the Absorbing Band of the Fiber (not enough).

Lower the Voltage of Near Side to a Safe Value, while Pulsing the Far Side.

Possible magic.

Test with trapezoidal light guide.

• There is enough space between the L-Gs for the LED board.

• We positioned the board 3 cm from the photocathode.

• We used the demo, (baby) calorimeter.

• We measured the pulse high at the near and the far side.

• The ratio near / far was 8 to 10.

• Variation because of positioning.

Pictures of Light guide with LED board.

Pictures of pulsesI

Near side

Far side

Pictures of pulses II

Near side

Far side

Other Approaches.

Return to fibers. Not as elegant as it sounds.

• Splitters Cost ~ 2000 $ for 16 channels

• Inflexible

• Need Groove on Light Guide.