Date: Tue, 28 Mar 2000 09:03:08 -0600
From: "Christl, Mark" 
To: "Fountain, Walt" 
Subject: Note to Fuki

Chamber configuration 
We have put together the chamber information for JACEE 14 and have included
a list (for the standard and pair-meter chambers) with details of the
structure, a drawing of the six chambers and their reference, and the
chamber size and design including wooden boxes. 

There were five standard chambers and 1 pair-meter on JACEE14.
The attached files show the nominal thickness for a standard chamber and a
pair-meter chamber. Below is a list of discrepancies for each chamber ( no
discrepancies means the chamber was packed as designed). The packing was
checked a second time when we de-stacked the chambers after the flight.
There are a few general points that I would like to make regarding these
details:

1) Wooden Boxes
The outer dimensions of all the wood boxes were 553.8mm X 453.8mm x 197mm (
230.5mm including thickness of bottom support plate). The top and sides of
the box used wood that was 12.7mm thick. The wooden top cover was 3/8"
(9.53mm) and the bottom support plate was 24mm thick. We do not have
detailed descriptions of the boxes after placement in Antarctica, but the
spacing between boxes is certainly less than 2mm and probably closer to 1mm.

2) Acrylic Liner
The black acrylic liners inclose the chamber materials with sidewalls 12.7mm
thick but are wrapped in layers of black tape adding another 1mm all around.
This is further inclosed in the rubberized barrier bag adding another 0.5mm
all around.The tape and barrier bag are not indicated in the drawings below.

3) Detector stack thickness (Standard chambers)
The nominal height of the detector stack (emulsion, lead,xray etc.) for the
5 standard chambers was 136mm but there was additional material below the
stack 1.56mm (foam, rubber barrier bag,paper and tape) and above the stack
50.80mm (foam), 2.56mm (additional foam+rubber bag) and 9.53mm (wood top).
The free space in the chamber then should be 197-(136+50.8+2.56+1.56)=
6.08mm. Since I did not pack previous JACEE chambers (1-8) I do not know how
this compares with the assembly of older chambers. In our case (JACEE14),
some of the difference (6.08mm) is likely to be due to non-uniformity of the
specified plate thickness and some space remaining between the many layers
but most of the 6.08mm is probably dead space at the top of the chamber.
During the stacking we compressed the chamber several times to remove air
and space between the plates. After sealing the rubber bag and putting it
under vacuum for a few days, the chamber is likely to have compressed some
more (perhaps a few millimeters). In any case, for simulation purposes I
believe the nominal height of the detector stack given in the attached list
is representative of the flight unit. Let us know if you have concerns with
this information or data.

4) Detector stack thickness (Pair-meter chamber)
The nominal height of the detector stack(emulsion, lead,xray etc.) for the
pair-meter chamber was 163.8mm and there was additional material below the
stack 1.56mm (foam, rubber bag etc.) and above the stack 11.0mm (foam)
2.56mm (foam+rubber bag) and 9.53 (wood top). The unused space in the
chamber then is 197-(163.8+11.0+2.56+1.56)= 18mm. The difference (18mm) for
the pair-meter chamber is quite large compared to the 5 standard chambers.
For this chamber we did not compress the stack when stacking the pair-meter
section because the CR39 was very fragile and we were concerned with
breaking the plates. The rubber bag was sealed after the stacking was
finished and evacuated for a short period after which it was vented to the
atmosphere. This was to prevent starving the CR39 of oxygen enroute to
Antarctica. 

5) All chambers were shipped to Antarctica upside down and the plates are
likely to have settled some during transport to Antarctica. Once in
Antarctica, the boxes were turned right side up and installed on the gondola
where they waited until launch. Some settling may have occurred while
waiting.

6) I will send the corrected final version of the chamber configuration in a
separate e-mail.

Below are pictorial drawings showing the dimensions mentioned above.