Vacuum System Test Plans

   DATE:	Nov 15, 1996
     TO:	S. Peggs
   FROM:	H.C. Hseuh

SUBJECT:	Vacuum System Test Plan During First Sextant Test
		=================================================

The Vacuum Group plans to carry out the following tests during the
First Sextant Test.  All the tests require tunnel access and most of
them will probably be done in February.  Some of these tests will be
run in parallel.  Please let me know if you need further information
on our test plan.

Testing of Kimo's Methods of Locating Leaks in Long Cryostats
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 Leaks of variable sizes will be bled in through the instrument valves
at the interconnects.  The helium pressure profile along the cryostat
will be measured with a leak detector and compared with the calculated
profile.
    System:	Inner arc cryostat (DU3 to Q4); IP6 triplet cryostat
    Temp.:	4K, ~55K, ~240K
    Period:	~1 week / ea

Measurements of Cryopumping Capacity of the Activated Charcoal for
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Helium in Short Cryostats
-------------------------
 The Helium adsorption capacity of the charcoal in the cryostats will
be measured and used to decide whether it is necessary to install
permanent turbopumps in the short cryostats.
    System:	Both triplet cryostats; Q8-Q9 cryostat
    Temp.:	4K
    Period:	~2 days / ea

Measurement of Total Helium Leak Rate in Each Cryostat and Cold Bore
--------------------------------------------------------------------
 From the pressure rise at this temperature, the total Helium leak
rate inside each cold zone can be estimated.
    System:	8 cryostats amd 10 cold bore regions
    Temp.:	~55K
    Period:	~2 days

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