Cryostation reservations

Ali K. Okyay aokyay at stanford.edu
Tue Aug 22 00:31:12 PDT 2006


Hi all,

I tend to agree with Ryan that long block reservations do limit the
availability of the station for other users. However, one also needs to
consider the amount of time it takes to bring the sample up to room
temperature after probing is finished. This seems to take as much time if
not more than cooling down. We are looking at a 4-5 hour overhead time per
sample. The rest of the time users do measurements, and more often than not
at more than a single temperature point, simply increasing the probing time
by a few factors. Given all the overheads, the current 2-day-max rule seems
ok to me, but I guess we could try a 24-hour-max limit as well.

Regards,
Ali


-----Original Message-----
From: Ryan Tu [mailto:ryantu at stanford.edu] 
Sent: Tuesday, August 22, 2006 12:06 AM
To: cryostation at snf.stanford.edu
Subject: Cryostation reservations

Dear All,

I would like to open a discussion to increase the availability of the
cryostation.  Currently users are blocking out up to three days at a time,
24 hours per day.  I am guessing that a large portion of that time is not
being used for actual probing, however, I would like to get feedback from
users as to how much of the reserved time is actually used.

Since the leak is now fixed, a pump down to appropriate levels before
cooling should take less than two hours and then the cool down itself should
take no more than an hour, for a total of three hours per sample load.  As a
start for the discussion how about limiting the reservation to a 8-10 hour
block for a 24 hour period.  This would give a user 5-7 hours of probing at
low temperatures.  If more time is needed, then the user can make additional
reservations in subsequent days.  Please reply for any comments or other
suggestions.  If users are finding that they need more than 5-7 hours to
probe, that would be useful as well.  I have just observed that in many
instances, large blocks of reserved times are unused and could be used by
other users.

Ryan






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