Re: [Brahms-l] run report

Dear Flemming and Radek,

flemming videbaek wrote:

> There will be beam-experiments from 10pm to 6 am, followed by a 18 
> hours maintenance period (18 hours for STAR). During this period 
> BRAHMS will look and hopefully fix a few outstanding problems
>  
> a) Investigate DC issue (preamp card (1), possible short in a v plane 
> scetion) (RK)

I made a look at the problem and it seems to me that this is not
short nor preamp. My first guess is that the problem is on the HV supply
site. Maybe reboot will help?
The observations are as follow:
1. The problem is related to T4-1-V1 and T4-1-V2 in the same way (these 
two planes are fed by the same HV channel).
2. Except of the low counting rate, all wires perform in the same (I 
would say reasonably) way.
3. Cathode and Field HV and currents are ok (it can not be in the case 
of short).
4. HV on 1-Vs (demand and actual) are ok, the only strange thing is 
negative current ~1microA -

Points 1. and 4. suggest the HV supply  problem. Points 2. and 3. rather 
exclude chamber related explanation.

Best regards
Pawel.

 

> b) Look for one missing TDC signal in beamBeam (BB)
> c) Investigate and possible replace L1458A (PS failure Saturday) (RAS,JH)
> d) Install a showermax slat for in-beam testing before going into ZDC 
> (DB,EB)
> e) Misc HV and signal issue for TFW2 (DB)
> f) install HV cables for showermax. (RAS,JH)
>  
> ----------------------------------------------------------------
> Flemming Videbaek
> Physics Department
> Brookhaven National Laboratory
>  
> e-mail: videbaek@bnl.gov <mailto:videbaek@bnl.gov>
> phone: 631-344-4106
>
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