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<font face="Helvetica, Arial, sans-serif">Hello everyone,<br>
I apologize for the extremely late notification, but you had
probably guessed it anyway. There will not be a meeting today.
We'll have a meeting four weeks from now.<br>
<br>
Here's an exhaustive update about the target:<br>
<br>
<b><u>NMR:</u></b> <br>
James Maxwell is assembling the latest version of the NMR Q-meter,
designed by himself and Hai Dong. James has also completed his
overhaul of the NMR software controls. The newest version
completely replaces LabView w/ James' homebrewed Python code.
I've seen screenshots, and it looks pretty good. We'll try both of
these during the next cool-down.<br>
<br>
<b><u>Target Cart:</u></b> <br>
The support frame for the target cryostat has been fabricated and
mounted to the electronics cart in the EEL. It needs to be painted
and aligned. Dave Griffith is installing all the electronics
cables on the cart now and running them through a retractable
cable tray attached to the cart. The tray will track with the
cryostat as it rolls over the cart, keeping the cables and some
some small vacuum hoses neatly in place.<br>
<br>
<b><u>Cryostat:</u></b><b> </b> <br>
James Brock and Casey Flanagan disassembled the cryostat for
modifications for the next cool-down. We'll add a small tube
inside the refrigerator that should give us a more accurate
measurement of the vapor pressure over the liquid helium bath.
This is needed for accurate calibration of the NMR signal. Mark
Hoegerl will weld attachment points on the back of the cryostat
for hanging it from the above-mentioned support frame. James
Brock is doing a major overhaul of the NMR & microwave
insert. This will include a new microwave horn/reflector on the
underside of the bath. He and I did some simple measurements on a
variety of different horn shapes last week. They do a nice job of
distributing microwave power over the 2 cm width of a target
sample, but not quite its full 4 cm length. James will have some
new designs 3D printed soon.<br>
<br>
<b><u>Installation:</u></b><br>
We still seem to be on Hall B's unofficial schedule for 2022.
When asked, I told Stepan Stepanyan that two months would be
required to install and get the target fully functional in Hall
B. James Brock and myself met with Hall B's engineer and
designer, Bob Miller and Cyril Wiggins, to discuss the
installation. Bob agreed to move the 500 liter buffer dewar of
liquid helium from its current location to the same level as the
target cryostat. This will permit us to use a shorter and more
efficient transfer line to the target refrigerator. Bob will
design and construct a small platform with handrails so we can
access the cryostat for loading and unloading ammonia samples
while the target is inside the central detector. Cyril will
design a support frame for the downstream raster magnet that
attaches to the same rails on the target electronics cart as the
cryostat. Finally, </font><font face="Helvetica, Arial,
sans-serif"><font face="Helvetica, Arial, sans-serif">we discussed
the location of the vacuum valve and thin window between the
cryostat and beam line.<br>
<br>
</font><b><u>Cool-down:</u></b><br>
We are on track for a cool in late November. Its primary focus
will be DNP of butanol and deuterated butanol samples and loading
and unloading same with the latest version of James Brock's
retraction mechanism. James Maxwell has been preparing the
samples.<br>
<br>
I think that's about all. Let me know if you have any questions.<br>
<br>
Best regards,<br>
Chris<br>
<br>
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--
______________________________________________________
Christopher D. Keith, PhD
Jefferson Lab, Suite 6 email: <a class="moz-txt-link-abbreviated" href="mailto:ckeith@jlab.org">ckeith@jlab.org</a>
12000 Jefferson Ave. ph: 757-269-5878
Newport News VA 23606 fax: 757-269-5235
______________________________________________________</pre>
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