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

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== Agenda ==
 
== Agenda ==
−
* Minutes from last meeting  https://halldweb.jlab.org/wiki/index.php/March_12,_2023,_FCAL_Insert_Installation_Meeting
+
* Minutes from last meeting  https://halldweb.jlab.org/wiki/index.php/April_12,_2023,_FCAL_Insert_Installation_Meeting
 
* Status of dis-assembly
 
* Status of dis-assembly
 
* Crystal/glass boudary
 
* Crystal/glass boudary
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== Minutes ==
 
== Minutes ==
−
* Went over the minutes from the last meeting
+
* Went over minutes of last meeting
−
* Significant discussion on shims -
+
* We discussed unstacking the first (top) row and how to do it. Malte and Tim will look at it tomorrow morning
−
** 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
+
* Discussed adding plastic sheet around shelves to keep out dust
−
** Matt Shepherd brought addition SS strap and shim material
+
* We will blow off modules with N2 gas before restacking
−
** The original stack up used shims at each step so we should have plenty to reuse if needed
+
* Malte looked at shelving and we have enough for 2400 modules (400 will not be used) if we use the top wall mounted shelf. Scot has bought (2) 2' high platforms to enable easy access.
−
** 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?
+
* It was pointed out that the modules should not be rotated when unstacked to keep the bases all pointing in the proper position
−
*** Sasha said the conductive rubber pad on the ComCal is coming apart so we would have to find something more robust.
+
* We discussed the interface between the crystals
−
*** Sasha will come up with a stacking sequence for crystals and develop shimming plan for crystals
+
** the consensus is that the 1.6mm thick thermacool silicone rubber sheet will be adequate on both sides as long as the edge of the glass blocks are as flat as possible
−
* 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
+
** the top and bottom crystal row interface will have a 160 micron thick stainless steel sheet separating from the glass to ensure no high stress points
−
** 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 glass blocks will be compressed beam right before installing crystals. This can be done one or more rows at a time
−
** The center left cooling plate is being cut into 3 pieces to make it more manageable
+
* We will use some "bad" glass modules to develop the horizontal compression requirement on the bottom row before installation. The total dimension should equal the existing FCAL dimension
−
* Malted stated that the existing signal cables will all be removed by today - we can remove chains in the morning
+
* It seems like a good idea to put 800 micron thermacool between the cooling blocks and the outer glass modules to soften and act as a spring
−
* We should be ready to pull cables out of dark room next week. Unstacking may start the following week
+
* Malte pointed out that on the existing LMS the LED boards did not all stay adhered to the acrylic. We should screw them in place for the FCAL2
−
* Discussed where rtd's go. 10 total on crystals some near center and edges US and DS flanges
+
* It was discussed that the sanding spec for the acrylic should be verified
−
* Discussed supporting the lead glass module flange above the crystals on the DS end
+
* No final decision on crystal LMS as far as the fibers being glued to the crystals. The remaining designs for the tungsten, rohacel and outer acrylic support depend on this decision
−
** 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
+
== Action Items==
−
** 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
+
* Tim to get samples of the thermocool sheets with and without adhesive (160 and 80 micron)
−
** Cannot support from end of glass module as housing is plastic
+
* Scot to procure clear plastic sheets to put around shelving
−
* Sasha updated that cables are on order
+
* Tim to update procedure to include items discussed
−
* Sasha stated that he ordered 200 silicon cookies that match original glass module parameters
+
* Malte/Tim to setup torque testing for horizontal compression
−
* Malte stated that he has spares of the PeeK threaded rods for the glass modules
+
* Malte/Scot to make acrylic sanding sample
−
* Malte will practice rewrapping of the modules as Matt has brought the fixture and some cut aluminized Mylar
+
* Sasha to decide on crystal LMS configuration
−
* 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
+

Latest revision as of 14:42, 2 May 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

  • Went over minutes of last meeting
  • We discussed unstacking the first (top) row and how to do it. Malte and Tim will look at it tomorrow morning
  • Discussed adding plastic sheet around shelves to keep out dust
  • We will blow off modules with N2 gas before restacking
  • Malte looked at shelving and we have enough for 2400 modules (400 will not be used) if we use the top wall mounted shelf. Scot has bought (2) 2' high platforms to enable easy access.
  • It was pointed out that the modules should not be rotated when unstacked to keep the bases all pointing in the proper position
  • We discussed the interface between the crystals
    • the consensus is that the 1.6mm thick thermacool silicone rubber sheet will be adequate on both sides as long as the edge of the glass blocks are as flat as possible
    • the top and bottom crystal row interface will have a 160 micron thick stainless steel sheet separating from the glass to ensure no high stress points
    • The glass blocks will be compressed beam right before installing crystals. This can be done one or more rows at a time
  • We will use some "bad" glass modules to develop the horizontal compression requirement on the bottom row before installation. The total dimension should equal the existing FCAL dimension
  • It seems like a good idea to put 800 micron thermacool between the cooling blocks and the outer glass modules to soften and act as a spring
  • Malte pointed out that on the existing LMS the LED boards did not all stay adhered to the acrylic. We should screw them in place for the FCAL2
  • It was discussed that the sanding spec for the acrylic should be verified
  • No final decision on crystal LMS as far as the fibers being glued to the crystals. The remaining designs for the tungsten, rohacel and outer acrylic support depend on this decision

Action Items

  • Tim to get samples of the thermocool sheets with and without adhesive (160 and 80 micron)
  • Scot to procure clear plastic sheets to put around shelving
  • Tim to update procedure to include items discussed
  • Malte/Tim to setup torque testing for horizontal compression
  • Malte/Scot to make acrylic sanding sample
  • Sasha to decide on crystal LMS configuration
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