[Dsg-halla] New step to check light guides in BigBite EM calorimeter supermodule assembly

[Bogdan Wojtsekhowski]

Hi Tyler,


Is 9am tomorrow OK for you?

Bogdan

________________________________
From: Tyler Lemon
Sent: Wednesday, May 15, 2019 3:46 PM
To: Bogdan Wojtsekhowski; dsg-halla at jlab.org
Subject: Re: New step to check light guides in BigBite EM calorimeter supermodule assembly

Hello Bogdan,

We should be able to meet tomorrow morning.

In regards to your point 2 below, is there a way we can use a torque wrench or some sort of guide to establish the correct amount to tighten the inset screws?

You told us just to tighten the screws until the small plate is about halfway between the lead glass and the end plate.

Since this doesn't seem to be working, a torque spec or guide would help prevent over-tightening.

-Tyler

From: Bogdan Wojtsekhowski
Sent: Tuesday, May 14, 2019 5:46 PM
To: Tyler Lemon
Subject: Re: New step to check light guides in BigBite EM calorimeter supermodule assembly


Hi Tyler,


I found that two SMs on the table have two BS33 each and some BK7

type have also indications to the glass problem. I reassembled both SMs

and replaced all problematic blocks.

Let us meet and discuss a few ideas:

1) How to inspect the block for the glass problem.

2) The level of the spring force which is adaquate.

3) SM handling aspects.
Please send me email about good time to meet.
Thank you,

Bogdan


________________________________
From: Bogdan Wojtsekhowski
Sent: Tuesday, May 14, 2019 1:50 PM
To: Tyler Lemon
Subject: Re: New step to check light guides in BigBite EM calorimeter supermodule assembly


Yes, it is correct.

We will use the blocks with BS33 glass light guides but

1) need to check for signes of glass breakage

2) concetrate the blocks in a few super modules which will

be installed in the top section of the full system.


Bogdan



________________________________
From: Dsg-halla <dsg-halla-bounces at jlab.org> on behalf of Tyler Lemon
Sent: Tuesday, May 14, 2019 12:05 PM
To: dsg-halla at jlab.org
Subject: [Dsg-halla] New step to check light guides in BigBite EM calorimeter supermodule assembly

Hello Bogdan,

Just to review what we discussed this morning, we will add the step to the supermodule assembly to check the florescence of the light guide to make sure that it is the correct glass material.

We will use the blue laser pointer to verify that the light guides fluoresce green and not red (red indicates the wrong, older light guide).

Best regards,
Tyler
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