Please see the first two pictures of the HV test at atmosphere done on April 19.

First picture shows a big spark between the Extraction Electrode mounting plate holder (at HV) to the Ground Electrode. Please note minimum gap between these electrodes is 7.8mm.

However the biggest visible spark was noticed at the bottom screw hole. (It is difficult to determine if at the 7.8mm gap were concomitant sparks occurring.)This spark started at 22kV and became stable above 24kV.

On April 20, 2017 Chad inspected this area with the Hot Cell camera and found a spark mark on the Extraction Electrode holder plate at the bottom screw hole. See the third picture.

Again it is very difficult with the existing Hot Cell cameras to inspect the areas where the gap is small (at 7.8mm gap between the conical surfaces of the Ground Electrode and Extraction Electrode holder)

In the second picture there are 2 small sparks: one on the top and another one on the right side at the lines wrapped in Fiber Glass. These sparks started at 20kV.

On April 21 the HV test was repeated with the Containment box ON and the sparks occurred again, at the same locations and at the same voltage.