sPHENIX HCal discussion

[Stefan Bathe <bathe AT bnl.gov>]

Dear HCal’ers,

To follow up on the discussion of the fiber-light blocker fit from the meeting:

According to Rich, the nominal diameter of the fiber ferrule is 3.0 mm and of the hole in the light blocker is 3.1 mm.

I measured several ferrules with a caliper and holes with hole gauges.  Since the hole gauges are in thousands of an inch (mils), I report the measurements in mils (not mm).  

For reference, 3.0 mm is 118 mils; 3.1 mm is 122 mils; and 1 mil is 1/4 mm.

I measured half a dozen ferrules, and they were all 119 +/- 0.5 mils (one was oblong in cross section and 120 in the long direction).  This is independent of whether or not there was a fiber embedded in the ferrule.

Then I measured two holes where the ferrule goes in without friction.  Those holes were both 119 mils.

Finally, I measured seven holes of tiles where we determined that there was too much friction.  Two of those were 118 mils, and five 117 mils.

My conclusion is that the issue is with the holes in the light blockers, which are about 0.1 mm below specs.

Regards,

Stefan

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Stefan Bathe

Professor of Physics
Baruch College, CUNY

Baruch:                                     BNL:
17 Lexington Ave                      Bldg. 510
office 940                                  office 2-229
phone 646-660-6272                phone 631-344-8490
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On Jul 29, 2019, at 11:02 AM, Lajoie, John G [PHYSA] <lajoie AT iastate.edu> wrote:

Dear HCAL’ers: 

 

We will have our next weekly meeting this coming Wednesday, July 31^st at 3PM BNL time:

 

https://indico.bnl.gov/event/6563/

 

I’m looking forward to a report from the 912 factory as well as an update on the 2018 test beam analysis. Additional topics are most certainly welcome!

 

John

 

John Lajoie

Professor of Physics

Iowa State University

 

(515) 294-6952

lajoie AT iastate.edu

 

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