[Halld-pid] [EXTERNAL] Re: Start Counter "warming"

Fri Nov 3 13:55:04 EDT 2023

Hello Beni,

I attached a document from Yi Qiang (2012) that is relevant to this discussion. It is also available in the GlueX docdb as 2449. Periodic annealing at 40 C is recommended in the document.

Best regards,
Fernando

From: Benedikt Zihlmann <zihlmann at jlab.org>
Sent: Friday, November 3, 2023 9:25 AM
To: Joerg Reinhold <reinhold at fiu.edu>; Fernando Barbosa <barbosa at jlab.org>; halld-pid at jlab.org; Werner Boeglin <boeglinw at fiu.edu>; Timothy Whitlatch <whitey at jlab.org>
Subject: Re: [EXTERNAL] Re: Start Counter "warming"

hi Joerg,

I absolutely agree that it is not obvious at all that this "annealing" will lead to an improvement.
The main reason is that it is cheap in labor and material do to it and we have the time to do it.

the higher the temperature the better or rather the faster the annealing happens.  The lower the temperature
the slower the process. A typical thermodynamic behavior, and it of course follows and exponential dependence.
In other words at room temperature you wait for ever, at 45 degree you wait a long time and at 100 degree it
would goes much faster.

cheers,
Beni

On 11/3/23 09:02, Joerg Reinhold wrote:
Hi Folks,

Another thing to check is the alignment of the SiPMs with the scintillators. My understanding is there is a carefully adjusted airgap. The detector has been handled by now numerous times, removed and again inserted into the detector. Just slight misalignments might lead to a loss in transmission to the SiPMs.

Beni makes the argument that sigma/peak does not change, which seems indicative of primary photon yield not having changed. But then, the paddles have quite some counterintuitive light collection as a function of z; i.e., the transmission seems to be best from the nose section. There are regions where sigma/peak is changing.

Other questions: would 45 C even be close enough to expect some annealing to happen. Naively, I would have expected the required temperature to be in the hundreds of degrees C.

Best,

Joerg

Dr. Joerg Reinhold, Professor (he/him/his)
Department of Physics
Florida International University
Phone: 305-348-6422 | reinhold at fiu.edu<mailto:reinhold at fiu.edu>
________________________________
From: Halld-pid <halld-pid-bounces at jlab.org><mailto:halld-pid-bounces at jlab.org> on behalf of Timothy Whitlatch via Halld-pid <halld-pid at jlab.org><mailto:halld-pid at jlab.org>
Sent: Wednesday, November 1, 2023 08:53
To: Benedikt Zihlmann <zihlmann at jlab.org><mailto:zihlmann at jlab.org>; Fernando Barbosa <barbosa at jlab.org><mailto:barbosa at jlab.org>; halld-pid at jlab.org<mailto:halld-pid at jlab.org> <halld-pid at jlab.org><mailto:halld-pid at jlab.org>; Werner Boeglin <boeglinw at fiu.edu><mailto:boeglinw at fiu.edu>
Subject: Re: [Halld-pid] Start Counter "warming"

The glass transition temperature is listed as 52C

Timothy Whitlatch PE (Virginia)

Hall D Chief Engineer

Jefferson Lab

757-269-5087

________________________________
From: Benedikt Zihlmann <zihlmann at jlab.org><mailto:zihlmann at jlab.org>
Sent: Tuesday, October 31, 2023 4:27 PM
To: Timothy Whitlatch <whitey at jlab.org><mailto:whitey at jlab.org>; Fernando Barbosa <barbosa at jlab.org><mailto:barbosa at jlab.org>; halld-pid at jlab.org<mailto:halld-pid at jlab.org> <halld-pid at jlab.org><mailto:halld-pid at jlab.org>; Werner Boeglin <boeglinw at fiu.edu><mailto:boeglinw at fiu.edu>
Subject: Re: Start Counter "warming"

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><mailto:halld-pid-bounces at jlab.org> on behalf of Werner Boeglin via Halld-pid <halld-pid at jlab.org><mailto:halld-pid at jlab.org>
Sent: Tuesday, October 31, 2023 2:48 PM
To: Fernando Barbosa <barbosa at jlab.org><mailto:barbosa at jlab.org>; Benedikt Zihlmann <zihlmann at jlab.org><mailto:zihlmann at jlab.org>; halld-pid at jlab.org<mailto:halld-pid at jlab.org> <halld-pid at jlab.org><mailto: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><mailto:halld-pid-bounces at jlab.org> on behalf of Fernando Barbosa via Halld-pid <halld-pid at jlab.org><mailto:halld-pid at jlab.org>
Date: Tuesday, October 31, 2023 at 2:05 PM
To: Benedikt Zihlmann <zihlmann at jlab.org><mailto:zihlmann at jlab.org>, halld-pid at jlab.org<mailto:halld-pid at jlab.org> <halld-pid at jlab.org><mailto: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><mailto:barbosa at jlab.org>
Sent: Tuesday, October 31, 2023 8:12 AM
To: Benedikt Zihlmann <zihlmann at jlab.org><mailto:zihlmann at jlab.org>; halld-pid at jlab.org<mailto:halld-pid at jlab.org>
Cc: Fernando Barbosa <barbosa at jlab.org><mailto: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><mailto:zihlmann at jlab.org>
Sent: Tuesday, October 31, 2023 7:20 AM
To: halld-pid at jlab.org<mailto:halld-pid at jlab.org>; Fernando Barbosa <barbosa at jlab.org><mailto: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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