Kicker test Nr 2

[Peter Winter <peter.winter@psi.ch>]

Hi all,

we just performed the test Francoise proposed by removing the fisher 
plug inside cabinet HV1.

Our test included the following steps:
1) Switching to a constant high TTL level (DC mode from endless gate 
generator)
2) Ramping HV2 to see that all red LEDs are ok at 5kV with fisher plug 
still inside. That confirmed that we have a high TTL
3) We removed the fisher plug and taped it in a safe position on the 
plastic shelf far away any metal.
     - ramping HV2 to 5kV with lower red LEDs ok, the upper were not 
lightened due to DC mode
     - ramping HV1 without current drawn to 5kV on negative polarity, 
upper red LEDs turned on, no red LED on bottom stack due to DC
4) We then decided to go to the kicking mode (5mus on at 1kHz) in order 
to also see the red LEDs on the lower stack of cards in HV1.
     - ramping HV2 to 5kV with all red LEDs ok (top ones bright, lower 
faint)
     - ramping HV1 to 2.4kV with 001mA, we observed that the red LED on 
the card DN-13 had NO red light, while all others were on
5) We reconnected the fisher plug with DC mode:
    - HV2 ok when ramping up
    - HV1 has immediately a rising current of several mA

Summarizing:
- It seems that the breakdown is somewhere between the fisher plug and 
the plate
- The card DN-13 still has no red light. Since this is en exchanged 
card, could the problem be connected with the optic fibre?
- When we first saw this breakdown we could go up twice to 2kV with no 
current. Only when the breakdown occured the current remained. Now the 
situation changed and we immediately see the breakdown current. Does 
that mean that the breakdown point worsened and became permanent.

Waiting for new proposals and conclusions
Brendan and Peter