Star-fst-l mailing list

[Tonko Ljubicic <tonko AT bnl.gov>]

Alright -- I'm on it and I'll let you know when done.


On Wed, Aug 18, 2021 at 2:28 PM Xu Sun <sunxuhit AT gmail.com> wrote:
>
> Hi Tonko,
>
> Yes. Please go ahead and let me know when you are finished.
> On my way to STAR, we could start to pull the detector after you are done.
>
> Best,
>
> Xu
>
> On Wed, Aug 18, 2021 at 8:15 AM Tonko Ljubicic <tonko AT bnl.gov> wrote:
>>
>> Hello Xu, all,
>>
>> before you pull the detector out today I would like 15-20 minutes to take 
>> a run
>> regardless of noise. This will give me some data to ponder while you
>> are checking the noise sources.
>>
>> Would that be possible? Now?
>>
>>          -- Tonko
>>
>> On Wed, Aug 18, 2021 at 1:37 AM Xu Sun <sunxuhit AT gmail.com> wrote:
>> >
>> > Hi Flemming,
>> >
>> > The bias voltage is different in two tests.
>> > For the test on 08/11/2021, the bias voltage is 50V for both inner and 
>> > outer. This is because the detector is only half way in and we couldn't 
>> > block the light.
>> > For the test on 08/17/2021, the bias voltage is 140V for inner and 160V 
>> > for outer.
>> >
>> > Best,
>> >
>> > Xu
>> >
>> > On Tue, Aug 17, 2021 at 7:34 PM videbaek <videbaek AT bnl.gov> wrote:
>> >>
>> >> Hi Xu,
>> >>
>> >> a question were the bias voltage the same in the two tests or did you go
>> >> to 140 for the outer. Just want to make sure I understand what you did.
>> >> I am coming in to the lab tomorrow as already planned and will see you
>> >> in the hall
>> >>
>> >> flemming
>> >>
>> >> On 2021-08-17 19:11, Xu Sun wrote:
>> >> > Hi All,
>> >> >
>> >> > We ramped the whole FST detector to the working HV last night and did
>> >> > a readout test for all the modules.
>> >> > There are two modules located at Disk 1 position 7 and Disk 1 position
>> >> > 11 (all belong to RDO2) showing an abnormal noise than the previous
>> >> > test. The RO test results can be found in the attached file
>> >> > (RDO2_140V_08172021.png).
>> >> >
>> >> > Both modules 1-7 and 1-11 were tested with 50V while the FST was half
>> >> > way in the cone on 08/11/2021. The results then were quite normal and
>> >> > could be found in the attached file (RDO2_50V_08112021.png).
>> >> > The only difference between two tests, as far as we are aware, is the
>> >> > position of the detector: on 08/11/2021 detector was half way in the
>> >> > cone and on 08/17/2021 detector was at final position.
>> >> > We have made sure the issue is on the purple cable and module side by
>> >> > swapping connections through the readout chain.
>> >> > Similar problems were found in the clean room RO test and were fixed
>> >> > by adding grounding to the aluminum ring or replacing the purple
>> >> > cable.
>> >> >
>> >> > We plan to pull the FST out tomorrow morning and check what happened.
>> >> > We also plan to add additional grounding of 1-7 and 1-11 to the
>> >> > aluminum ring instead of  only grounding to the T-board since it is
>> >> > almost impossible to change the purple cable for Disk 1 (most inner
>> >> > disk) on the scaffolding.
>> >> >
>> >> > Best,
>> >> >
>> >> > Xu
>> >> > _______________________________________________
>> >> > Star-fst-l mailing list
>> >> > Star-fst-l AT lists.bnl.gov
>> >> > https://lists.bnl.gov/mailman/listinfo/star-fst-l
>> >>
>> >> --
>> >> Flemming Videbaek
>> >> senior scientist
>> >> videbaek @ bnl.gov
>> >> Brookhaven National Lab
>> >> Physics Department
>> >> Bldg 510D
>> >> Upton, NY 11973
>> >>
>> >> phone: 631-344-4106
>> >> cell     :  631-681-1596
>> >
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