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[Xu Sun <sunxuhit AT gmail.com>]

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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