Difference between revisions of "JEF meeting, June 28, 2019"

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(Agenda)
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=Agenda=
 
=Agenda=
 
[https://halldweb.jlab.org/JEF Magnetic shielding studies]
 
[https://halldweb.jlab.org/JEF Magnetic shielding studies]
 +
 +
=Minutes=
 +
Attendees:  Wolfgan, Josh, Simon, Sasha, Zisis
 +
* Magnetic field studies more or less complete
 +
** From last time:  Sasha suggested moving FCAL assembly 35 cm downstream to reduce field in PMT region for lead tungstate
 +
*** Could stack lead glass blocks that we remove from the central region in the outer radius to improve acceptance
 +
** Studies with 350 micron mu-metal shielding + iron housing look promising -- added additional 50 micron mu-metal
 +
*** For 60 Gauss longitudinal external field -> 2 Gauss in center of housing+mu-metal shield
 +
*** PMT response in central position of 3x3 array flat up to about 40-50 Gauss longitudinal field
 +
*** No saturation of mu-metal seen
 +
*** Currently using 1020 steel, could be annealed for ~20-30% improvement

Revision as of 09:16, 1 July 2019

Meeting time and location= 1:00 pm EST (JLab time) F228


Connection instructions

We are using BlueJeans Video/Audio conferencing. Our meeting ID number is 370588741. Click "Expand" for more details.

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  • If connecting via Web Browser: click this link (no passcode is needed):
  • If connecting via Phone: Dial one of the following numbers and then enter the meeting ID above and hit "#" or "##"
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    • Enter meeting ID above

Agenda

Magnetic shielding studies

Minutes

Attendees: Wolfgan, Josh, Simon, Sasha, Zisis

  • Magnetic field studies more or less complete
    • From last time: Sasha suggested moving FCAL assembly 35 cm downstream to reduce field in PMT region for lead tungstate
      • Could stack lead glass blocks that we remove from the central region in the outer radius to improve acceptance
    • Studies with 350 micron mu-metal shielding + iron housing look promising -- added additional 50 micron mu-metal
      • For 60 Gauss longitudinal external field -> 2 Gauss in center of housing+mu-metal shield
      • PMT response in central position of 3x3 array flat up to about 40-50 Gauss longitudinal field
      • No saturation of mu-metal seen
      • Currently using 1020 steel, could be annealed for ~20-30% improvement