[Halld-pid] Start Counter "warming"

Tue Oct 31 16:27:52 EDT 2023

wow,
that is the same epoxy that is use in boat building together with 
fiberglass.

so a 45 degree C is the max it seems.

cheers,
Beni

On 10/31/23 16:08, Timothy Whitlatch wrote:
> Hi All,
>
> It looks like the weakest link is the West System 105/205 epoxy. It is 
> good to about 50C.
>
> Cheers,
>
> Timothy Whitlatch PE (Virginia)
>
> Hall D Chief Engineer
>
> Jefferson Lab
>
> 757-269-5087
>
> ------------------------------------------------------------------------
> *From:* Halld-pid <halld-pid-bounces at jlab.org> on behalf of Werner 
> Boeglin via Halld-pid <halld-pid at jlab.org>
> *Sent:* Tuesday, October 31, 2023 2:48 PM
> *To:* Fernando Barbosa <barbosa at jlab.org>; Benedikt Zihlmann 
> <zihlmann at jlab.org>; halld-pid at jlab.org <halld-pid at jlab.org>
> *Subject:* [Halld-pid] [EXTERNAL] Re: Start Counter "warming"
>
> Hi Beni,
>
> When warming the detector remember that the scintillators are held 
> together with a self-clinging plastic packing wrap. I do not know how 
> this reacts when it gets warm (I think we still have some of the 
> material here somewhere), we do not want the detectors getting loose 
> or too tight. Also, the rohacell foam support and the carbon fiber 
> inner tube are glued to the aluminum mandril and you might want to ask 
> the engineers about the temperature properties of the glue that was used.
>
> Kind regards
>
> Werner
>
> Werner Boeglin
>
> Professor
>
> Dept. of Physics, Florida International University
>
> CP236 , MMC
>
> 11200, SW 8th Street
>
> Miami, FL 33199
>
> phone: (305) 348 1711
>
> boeglinw at fiu.edu <mailto:boeglinw at fiu.edu>
>
> *From: *Halld-pid <halld-pid-bounces at jlab.org> on behalf of Fernando 
> Barbosa via Halld-pid <halld-pid at jlab.org>
> *Date: *Tuesday, October 31, 2023 at 2:05 PM
> *To: *Benedikt Zihlmann <zihlmann at jlab.org>, halld-pid at jlab.org 
> <halld-pid at jlab.org>
> *Subject: *Re: [Halld-pid] Start Counter "warming"
>
> Note: This message originated from outside the FIU Faculty/Staff email 
> system.
>
>
> Hello Beni,
>
> Looking at the plots, I agree with your assessment of significant gain 
> degradation. However, I am a bit dubious that the gain can be 
> recovered by that much via annealing. This will be an interesting test.
>
> Best regards,
> Fernando
>
> -----Original Message-----
> From: Fernando Barbosa <barbosa at jlab.org>
> Sent: Tuesday, October 31, 2023 8:12 AM
> To: Benedikt Zihlmann <zihlmann at jlab.org>; halld-pid at jlab.org
> Cc: Fernando Barbosa <barbosa at jlab.org>
> Subject: RE: Start Counter "warming"
>
> Hello Beni,
>
> I suggest 40 to 60 degree C and 1 month of annealing should provide 
> considerable recovery. I would also suggest keeping the bias off.
>
> Best regards,
> Fernando
>
> -----Original Message-----
> From: Benedikt Zihlmann <zihlmann at jlab.org>
> Sent: Tuesday, October 31, 2023 7:20 AM
> To: halld-pid at jlab.org; Fernando Barbosa <barbosa at jlab.org>
> Subject: Start Counter "warming"
>
> Hi Fernando, Werner,
>
> in view of the fact that we do see a significant degradation in the 
> gain of the Start counter response over the years I was thinking if 
> active "annealing" may help.
> see also:
> https://urldefense.com/v3/__https://halldweb.jlab.org/wiki/index.php/Start_Counter_Operations*Run_Period_Winter_2023__;Iw!!FjuHKAHQs5udqho!Nk-OYfMHDbkBaRlkuKDCils8sI-c1M2TiRC4IK3Omz3pN4U1-69uADQTkIB3RpB9iK3wYcztgQCBt_1Rmrw$ 
> <https://urldefense.com/v3/__https:/halldweb.jlab.org/wiki/index.php/Start_Counter_Operations*Run_Period_Winter_2023__;Iw!!FjuHKAHQs5udqho!Nk-OYfMHDbkBaRlkuKDCils8sI-c1M2TiRC4IK3Omz3pN4U1-69uADQTkIB3RpB9iK3wYcztgQCBt_1Rmrw$>
>
> It is not clear why this drop in gain occurred. It does not seem to be 
> related to a loss in light since the ration of width divided by 
> mean-amplitude has not changed much, and in the nose area not at all 
> (this is the middle histogram of the plot). So the source of the loss 
> in gain may be related to the SiPM photo sensor itself?
>
> We know "annealing" helps with regards to dark current but I am not 
> aware of recovering gain.
> An active annealing can be employed by covering the photo sensor area 
> with a "heating blanket"
> and warm up the region to a certain temperature. The question is what 
> temperature can be considered "save" with regards to the PCB board and 
> electronics as well as the plastic scintillators.
>
> how high in temperature do you think can we go without affecting these 
> parts? 70 degree Celsius or even more?
> The time frame for such an "annealing" attempt would be of order 1 month.
>
> any comments?
>
> cheers,
> Beni
>
>
>
>
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