Re: Muon-On-Request

[Gary D Wait <wait@triumf.ca>]

Peter
I dont understand what could cause this fault. Perhaps the controls are 
in a strange mode, or there is a grounding rod that was not removed. 
Maybe if everything is powered down and started over it might work. Not 
too hopeful about that. If one LED is out at 1.4kV it is likely due to 
the low voltage and a lower output of that LED. One card not turning on 
would not cause the problem you described. Perhaps the trigger unit is 
sending noise into the system. You could try removing the trigger 
signals from the HV1 side and trying again. Hopefully Mike will have 
some good ideas.

Regards
Gary


Winter Peter wrote:

> Dear Mike,
>
> this evening we were trying to start the kicker again after it wasn 
> running on HV the last days. While trying to ramp the HV up, we had a 
> current regulation on the HV1 side. We could go up until 2kV and then 
> suddenly the current went to 112mA and the voltage dropped to 0.41kV. 
> There was a red LED on the small black box at the 'NEG 1'. We reset 
> the kicker and went up with the HV on the HV2 side without problems. 
> Then we tried slowly to ramp the HV1 side again and at 1.4kV we could 
> see the red LEDs being on. The current was ~75mA and therefore still 
> below 112mA but higher than usual. We then noticed that on the lower 
> stack of the cards in HV1 the card DOWN-13 didn show a red LED.
>
> With the online help of Francoise we took out this card and checked 
> the resistance. It showed 1.6MOhm in one direction (similar to one of 
> the spare cards). Then we put it back and bypassed the door interlock 
> in order to measure the voltage on the resistor C13. That measurement 
> gave 15.1 V while the two neighbouring cards had 14.9 and 15.06 V for 
> this resistor. According to what I learned from Francoise, this card 
> might not be a problem.
>
> Now we don want to switch on this half of the kicker before we have 
> some advice what to do next. Do you have any suggestions / ideas for 
> the high current? In principle we could exchange the card with a spare 
> one and test the kicker again but we rather wait for your answer.
>
> Looking forward for any suggestions,
> best greetings
> Peter
>