Mini BCAL Channel Study

The mini BCAL Module tests

On 3rd March 2023, Chris set up a LED pulsar box to verify the working of the SiPM modules that will be used for the mini BCAL EIC test.

Module-49 and Module-50 used are spares for the BCAL modules for 2011 that were tested during this study.
Module-50 was tested however, channels 3 and 4 showed very small amplitudes for both Upstream and downstream, probably indicating that the bias voltage set were not right for them.

The pulsar box was a dark light-tight box with a blue LED constantly flashing from the bottom.
The SiPM modules are mounted on the top, with a casket and a black cloth to seal off any light leaks into the system,
Voltage supplies are given by the Weiner Crate (ISEG for high voltages and MPOD for low voltages) to the BCAL distribution boxes as shown in [Slide 12]. Due to instrumental issues with the ISEG controller, Voltages had to be manually set using the knobs and therefore, the Over Bias tests were not able to be performed.
2 LEMO cables are then connected from the output channels onto the scope. One cable labelled 'A' (Yellow in the scope) corresponds to the ADC output, while the other cable labelled 'T' (blue in the scope) corresponds to the TDC output
The output from each channel (fADC and TDC) is checked in the oscilloscope for its output characteristics and recorded accordingly.

The pulsar box is shown below.