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Yi,<br>
<br>
You may be right that 1 rem is not very much, but that is the
interval we would like to start off with. I cannot demand things
that you do not wish to do, but we do ask that until we have data
in-hand and have a chance to analyze it, DO NOT give this SiPM more
than 10 rems (uncorrected units). Do we agree on this?<br>
<br>
If you could provide us with 3-5 measurements in the interval 1-10
rems, with one at the beginning and another at the end, we would
greatly appreciate it.<br>
<br>
-Richard J.<br>
<br>
<br>
On 8/23/2010 1:30 PM, Yi Qiang wrote:
<blockquote type="cite" cite="mid:4C72B04A.8070908@jlab.org">
Hi Richard and Igor,<br>
<br>
Without attaching the DAQ together to the device during the
irradiation, it's not very realistic to take measurements every 1
rem ( every other hours assuming 0.5 rem/H). My experience with
Hamatasu and SensL units tells us that the increase of the
radiation damage can be well fitted by a second order polynomial
up to 100 rem. So I suggest that we make the gap larger. Here I
have a preliminary 48 hour schedule:<br>
day 1: 9:00 am, initial test, start of irradiation<br>
day 1: 4:00 pm, second test with 3.5 rem<br>
day 2: 9:00 am, 3rd test with 12 rem<br>
day 2: 4:00 pm, 4th test with 15.5 rem<br>
day 3: 9:00 am, 5th test with 24 rem, end of irradiation<br>
Then we will have 5 data point to get reasonable damage trend. The
increase of the dark rate will be about factor of 4 if similar to
Hamamatsu units (or 2 if similar to SensL units).<br>
What do you think?<br>
<br>
Cheers,<br>
Yi
<pre cols="72" class="moz-signature">------------------------------------------------------------
Yi Qiang Thomas Jefferson National Accelerator Facility
Staff Scientist 12000 Jefferson Lab 12_3/F351
<a href="mailto:yqiang@jlab.org">yqiang@jlab.org</a> Newport News, VA 23606
Phone:(757)269-7237 Fax:(757)269-6331
<a href="http://www.jlab.org/%7Eyqiang/web">http://www.jlab.org/~yqiang/web</a>
------------------------------------------------------------</pre>
<br>
On 8/23/2010 12:53 PM, Richard Jones wrote:
<blockquote type="cite" cite="mid:4C72A775.4040109@uconn.edu"> Yi,
<br>
<br>
Please follow the link under Notes on today's meeting agenda
page (linked below) to the page containing our proposed run plan
for measuring radiation damage in our SiPM. <br>
<br>
<a href="http://www.jlab.org/Hall-D/software/wiki/index.php/BLTWG_Meeting_08/25/2010">http://www.jlab.org/Hall-D/software/wiki/index.php/BLTWG_Meeting_08/25/2010</a>
<br>
<br>
Please follow up with any questions or problems with this plan.
Note in particular that we would like to see initial
measurements taken every 1 rem of dose, until you have
determined the sensitivity of the device. Continue this until
the dark rate has increased by a factor 2, then stop and leave
it for days (weeks) to watch the device recover. Once we see
these data, we will review what should be done next with you. <br>
<br>
-Richard J. <br>
<br>
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