Kn Calculations for Circuit Board Probes in Hall C Quadrupoles
Student: Daniel Akers
School: Old Dominion University
Mentored By: Joe Meyers
Jefferson Lab uses a number of magnets to steer the accelerator beam. The Magnet Measurement Facility (MMF) uses a number of methods to gather data on the magnets after they have been refurbished. Previously, testing was done using "stretched wire" data collection, where a thin copper wire is run through the magnets and gathers data as it moves. Another common method was to use rotating copper coils, which works in much the same way. More recently circuit board probes have been used. The purpose of this work was to calibrate the circuit board probes and to verify that they produced repeatable results, which were accurate to the stretched wire data. This was done by collecting data from the Hall C Moller quadrupole magnets with the circuit board probes, comparing the data to the data gathered from the stretched wire measurements, and calculating the Kn constants for the probes. Kn being a constant describing sensitivity. Calculations were done through Microsoft Excel and other software. The results demonstrated that the circuit board probes were a much more efficient method, and the data was very close to the stretched wire data. The work itself also demonstrated the data could be done in a fraction of the time. Previously these measurements took hours for a complete test with hysteresis and multiple amperages. Now testing can be done within about 20-30 minutes. In the future the Kns will have already been calculated, which means that all of the testing, data collection, and analysis will be done much faster.