Difference between revisions of "Visual inspection"
From GlueXWiki
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| − | Image:glass_glass_prob.jpg | Fig. 1 Broken glass | + | Image:glass_glass_prob.jpg | Fig. 1 Broken glass. |
</gallery> | </gallery> | ||
<gallery> | <gallery> | ||
| − | Image:glass_wrap_prob.jpg | Fig. 2 Wrapping issue: teared Aluminized mylar, can be fixed without disassembling module | + | Image:glass_wrap_prob.jpg | Fig. 2 Wrapping issue: teared Aluminized mylar, can be fixed without disassembling module. |
| − | Image:glass_wrap_prob1.jpg | Fig. 3 Wrapping issue: Al layer peeled off | + | Image:glass_wrap_prob1.jpg | Fig. 3 Wrapping issue: Al layer peeled off. |
| − | Image:glass_wrap_prob2.jpg | Fig. 4 Wrapping issue: Al layer peeled off, | + | Image:glass_wrap_prob2.jpg | Fig. 4 Wrapping issue: Al layer peeled off, wrapping foil is teared. A newly wrapped module is shown on the top. |
</gallery> | </gallery> | ||
<gallery> | <gallery> | ||
| − | Image:glass_pmt_prob.jpg | Fig. 5 Damaged PMT | + | Image:glass_pmt_prob.jpg | Fig. 5 Damaged PMT. |
Image:glass_color_prob.jpg | Fig. 6 Colored lead glass module, possible radiation damage issue. Can be seen without removing steel flange. | Image:glass_color_prob.jpg | Fig. 6 Colored lead glass module, possible radiation damage issue. Can be seen without removing steel flange. | ||
| − | Image:glass_color_prob1.jpg | Fig. 7 Colored lead glass module | + | Image:glass_color_prob1.jpg | Fig. 7 Colored lead glass module. |
</gallery> | </gallery> | ||
Revision as of 11:22, 18 October 2022
Fig. 1 Broken glass.
Fig. 2 Wrapping issue: teared Aluminized mylar, can be fixed without disassembling module.
Fig. 3 Wrapping issue: Al layer peeled off.
Fig. 4 Wrapping issue: Al layer peeled off, wrapping foil is teared. A newly wrapped module is shown on the top.
Fig. 5 Damaged PMT.
Fig. 6 Colored lead glass module, possible radiation damage issue. Can be seen without removing steel flange.
Fig. 7 Colored lead glass module.
Possible issues with lead glass module
- Broken lead glass, see Fig. 1 (module taken from the FCAL prototype)
- some problems can be seen by looking on the lead glass block from the side opposite to the PMT
- lead glass module has to be disassembled; the glass block has to be replaced.
- Issues with wrapping:
- small damages (holes) in the Aluminized mylar, see Fig. 2. This can be fixed by using Al sticky tape, thickness < 20 um
- Aluminum layer in the wrapping foil peels off or adheres to the glass block (penetrates into the block):
- Fig. 3 and Fig. 4: Aluminum layer peeled off resulting in some transparent holes in wrapping.
- recommend to disassemble and re-wrap the lead glass block
- Issues with Silicon cookies
- Inspect optical coupling of the glass block and the PMT by looking inside the crystal from the side opposite to the PMT
- Possible damages of PMTs during deinstallation (see Fig. 5)
- Glass blocks with discoloration signs (due to radiation)
- some glass blocks may have a brown tint (see Fig. 6 and Fig. 7)
- recommend to replace them
