Testing Voltage Divider Circuit Boards for Use at Thomas Jefferson National Accelerator Laboratory

Photomultiplier Tubes (PMTs) are robust and cost-effective devices for detecting the weak light produced by subatomic particles passing through matter. They serve the dual purpose of converting light into an electrical signal via the photoelectric effect and amplifying this electrical signal for further processing. This amplification occurs in stages (typically 10-12 stages), each stage at a slightly higher electrical potential than the previous. Resistive voltage divider arrays are used to provide these potentials. The JMU Particle and Nuclear Physics group designed, built, and is currently assembling and testing ~1100 voltage dividers for the electromagnetic calorimeter ECAL which will operate in Hall A at Jefferson Lab as part of a group of experiments aimed at measuring the electric and magnetic form factor of the proton and neutron. In this presentation we concentrate on the testing of the wiring of these PMT voltage dividers. To ensure the potential difference ratios are correct and that a readable signal can be obtained, each voltage divider is tested using analog-to-digital converters and run through two systems programmed to assess their operability.