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[Tonko Ljubicic <tonko AT bnl.gov>]

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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