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[Zhenyu Ye <yezhenyu2003 AT gmail.com>]

Thanks for the email, Rahul. I don’t see any testing of the Tygon tubes that you asked for in the documents, but description of various problems PHENIX had, especially the one due to electric charges built up on the Teflon tubes. One of the documents mentioned a plan to look into dissipate the charge by adding additive. I think we should be worried about our plastic tubes.

Did PHENIX remove Teflon tubes, but still kept Tygon tubes in their system?

Did PHENIX added FC-4400 or something else? 

I heard there was a disaster to their VTX in 2016 that half of the detector was not functional anymore. Does anyone know what it was?

Zhenyu

The start of Run-14 was plagued with tribo-electric charging of external Teflon cooling lines.  Although we have used Teflon tubing in the past, the magnitude of static buildup was much greater in Run-14 than in any past run.  As Novec 7200 travels though the detector, it picks up electrostatic charge and deposits it on the Teflon return lines leaving the detector.  These lines built up enough charge that they eventually discharged to each other or grounded surfaces.  The electrostatic arcing was energetic enough that it penetrated through the Teflon tubing causing pinhole leaks.  

The Teflon tubing was the weakest link in the system because of its thickness and dialectic strength.  We replaced all return lines leaving the VTX/FVTX with grounded corrugated stainless steel tubing during Run-14 (see figure 3).  For Run-15, all Teflon will be removed from the cooling system and replaced with stainless steel to ensure proper operation.  

In addition to removing Teflon tubes from the cooling loops, we are working on a solution to dissipate the charge that is being generated by the fluid.  After testing some additive samples, 3M’s FC-4400 is the most promising for our application.  FC-4400 is a high purity antistatic additive typically used when engineering resins.  Tests were performed using parts-per-million levels of the additive in Novec 7200.  Electrostatic charge no longer occurred in our test setup which constructed of similar materials used our cooling system.  Work will be done this summer to test the additives compatibility with detector components. 

On Jun 18, 2021, at 9:42 AM, Sharma, Rahul <rsharma AT bnl.gov> wrote:

Dear All,

Check the attached documents from PHENIX. 

•  Rahul

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From: Robert P. Pisani <pisani AT bnl.gov>
Sent: Friday, June 11, 2021 8:49 AM
To: Sharma, Rahul
Cc: Soja, Robert
Subject: Re: Testing Documents for Tygon/Versilon 2001

 

Sorry for the delay,  I had to pull the files from my old PC.   I attached a few files with some issues we had in the past.   I am still looking for a doc with the compatibility testing that was done.   

On Mon, Jun 7, 2021 at 4:03 PM Sharma, Rahul <rsharma AT bnl.gov> wrote:

Hi Robert,

 

You guys must have done various tests (Radiation Test, Pressure Test and NOVEC compatibility test) on The Tygon 2001 tubing. Can you please send me the data/documents from your testing?

 

• Rahul

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\~/~\~/~\~/~\~/~\~/~\~/~\~/~\~/~\~/~\~/~\~/~\~/~

Robert Pisani
Senior Physics Associate 

Brookhaven National Laboratory
Bldg 510C

Upton, NY 11973

Phone:631-344-5301
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<Run14CoolingUpdated.docx><VTXPixelPressure_Leaks2014.pdf><CoolingSystemDracy.docx>_______________________________________________
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