Difference between revisions of "April 20, 2023, FCAL Insert Installation Meeting"

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(Minutes)
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== Minutes ==
 
== Minutes ==
* Went over the minutes from the last meeting
 
* Significant discussion on shims -
 
** Malte has a large number of SS straps from the original modules and will serve as the shims to make up for the difference in module orientation of the lead glass blocks
 
** Matt Shepherd brought addition SS strap and shim material
 
** The original stack up used shims at each step so we should have plenty to reuse if needed
 
** Discussed shimming the glass/crystal interface to get good and straight, maybe a sheet all around to give a flat surface for the crystals? Also a conductive rubber pad?
 
*** Sasha said the conductive rubber pad on the ComCal is coming apart so we would have to find something more robust.
 
*** Sasha will come up with a stacking sequence for crystals and develop shimming plan for crystals
 
* Talked about squeezing one glass module row at a time to ensure we get a proper stack - this can be done and the left plate is loosened to allow the next row
 
** If we wish to squeeze the beam right glass modules (1 row at a time) to set up vertical interface with crystals, we can do that with a tool before the crystals (2 rows) are installed
 
** The center left cooling plate is being cut into 3 pieces to make it more manageable
 
* Malted stated that the  existing signal cables will all be removed by today - we can remove chains in the morning
 
* We should be ready to pull cables out of dark room next week. Unstacking may start the following week
 
* Discussed where rtd's go. 10 total on crystals some near center and edges US and DS flanges
 
* Discussed supporting the lead glass module flange above the crystals on the DS end
 
** May interfere with cabling the crystal bases
 
** Glass modules have housing DS that is smaller than the glass - all load would be put into the first layer joint
 
** both glass and crystal modules are designed to be supported by the glass/crystal
 
** Glass Module CG is over crystal so it should be ok
 
** Cannot support from end of glass module as housing is plastic
 
* Sasha updated that cables are on order
 
* Sasha stated that he ordered 200 silicon cookies that match original glass module parameters
 
* Malte stated that he has spares of the PeeK threaded rods for the glass modules
 
* Malte will practice rewrapping of the modules as Matt has brought the fixture and some cut aluminized Mylar
 
* Discussion ensued on the Light Monitoring system - stll no decision on the design and method. We will have a separate meeting
 
** Time is getting short if we do not wish to hold up the assembly waiting for parts. Need to decide ASAP
 
* As found measurements of existing lead glass stack up [[Media:FCAL_module_stack.pdf]]
 
** The detector was measured from the outside of the aluminum plates that hold in the modules
 
** Subtract 18.16mm from beam left to take out plate and shim thickness
 
** Subtract 19.69 mm from beam right
 
** Subtract  20.19mm from top
 
** Subtract 16.13mm from bottom
 
** Bottom line, the vertical stack is 1.37 mm higher than the expected value and .62 mm wider over 59 modules
 
** Lower half is .66mm more than upper half
 
** Beam left is .43mm more than BR
 
** This may be due to shims being used. We will see when we take it apart
 

Revision as of 06:21, 20 April 2023

Meeting Time and Place

Wednesday April 20, 2023 9am At Jefferson Lab, Hall D Counting House and on Zoom https://jlab-org.zoomgov.com/j/1619449114?pwd=UFlVQ1dWTGZ0ZkVYSEx5QzE4YUI3dz09&from=addon meeting ID: 161 944 9114 Passcode: 562689

Agenda

Minutes