Stable & Repeatable Ramping of 170 kV/cm Electric Field

This week we hit a milestone by successfully running a ramping simulation to 170 kV/cm for ~ 1 hr. This is approximately 15% higher than the goal we set out to reach and more than double the electric field that we were able to achieve during the Ra EDM data run two years ago.

Before starting the ramping simulation, we did a standard step-voltage ramping procedure to put a voltage difference of 25.0 kV across our electrodes. This value allowed us to hold a field at 180 kV/cm for at least 15 min before ramping back down to 0.0 kV.

We then programmed a wave-form generator to produce a square-wave function tosimulate the ramping done on the main experiment at Argonne National Laboratory in Chicago. The square wave was set to ramp from 0.0 directly to 23.8 kV giving us the desired 170 kV/cm at a 1.4 mm gap between the electrodes. We were able to continue this simulation for at least an hour before stopping the simulation due to time constraints. We are optimistic that we will be able to continue up to 180 kV/cm which is the maximum field we can produce at our current gap size. -ALP

In the picture below, you can see the leakage current stabilize around <10 pA (above) after each change of the field during the ramping simulation (below).2017-07-07-field-current-grid-ramp-test