Undergraduate Research at Jefferson Lab

Achieving Charge Equalization for the Coordinate Detector used in the Super Big Bite Spectrometer Collaboration

Student: Katie Whitcomb

School: Christopher Newport University

Mentored By: Peter Monaghan

The SBS suite of experiments aims to accurately measure the electromagnetic form factors in a nucleon. Part of the SBS project includes the commissioning of the Coordinate Detector (CDet), a PMT based detector used to determine the vertical component of an electron's trajectory. The focus of this project is to equalize the ADC values for all pixels in each PMT so commissioning of CDet can progress. To normalize ADC values, the raw ADC values were recorded and used as input for a formula which outputs the resistors to be used in that pixel of the PMT. Overall, the formula used to calculate resistor values was effective, but occasionally, the initial raw ADC values appeared to be inaccurate. This resulted in recalculating resistances through several back calculations, which then produced the desired normalization. Based on these results, it is shown that charges can be effectively reduced and equalized, given the initial measurement of the mean ADC. As a result, the modules involved in CDet will continue to be commissioned.