GBAR Update! 8-4-19

Getting in Line Last week: playing with the location of the potential well within the Riken trap to align our particle beam If the beam is well aligned, measurements from different locations should be nearly identical If not, we need to change the position of our electron gun (or the entry point of our positrons) Ran sequences of experiments with electron gun at certain positions and the well located at the beginning, middle and end of the trap Compared results and tried to refine the position of the gun

A Potential Problem... We ran into problems with these experiments, for a few reasons Method we were using to change the position wasn’t very precise Electrodes in the trap were at a different potential than the one we set them at! Calibrate for mechanical errors Measure the actual output at different voltages, and do a linear fit Use the line of each electrode to get a more accurate output that accounts for error This still doesn’t give us the exact output potential that our particles interact with at any given moment

cRIO Compact RIO (Compact Reprogrammable In/Out) Real-time controller chassis User-programmed FPGA Customizable I/O modules Ethernet connection Used to do real-time measurements of devices, can be accessed anywhere on the network

cRIO Use this to monitor potentials from Riken trap in real time Wire to amplifier output to read voltages Specific output will allow us to better understand what’s going on inside the trap Practice: measure signal from one waveform generator Connect cRIO to computer and configure ** Download LabVIEW FPGA software *** Learn how to program with LabVIEW FPGA * Write “simple” program to read waveform from channel !! Adapt this program to one that will read waveforms (potentials) from multiple channels and save data

“Two electrons walk into a GBAR “Two electrons walk into a GBAR. ‘See,’ one says to the other, ‘I told you this place had potential!’”