<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000'>Hi Dan,<br><br>We recalibrated the Hall probes yesterday. All except probe 4 look basically the same. 4 has changed by as much as 27 Gauss at 1.7T decreasing to no change at 500 Gauss. This may have been drifting during the past 10 days since the previous calibration.<br>The good news is....I broke probe 4 and we are replacing it.<br><br>We will recalibrate before each configuration in the future.<br>Attached is the updated calibration sheet.<br><br>We have changed the setup to configuration 6 and it will be fiducialized this afternoon. We should map config 6 Monday.<br><br><div><span name="x"></span>Tim Whitlatch<br>Hall D Engineer<br>Jefferson Lab<br>12050 Jefferson Ave ste 402<br>Newport News, Va 23606<br>757-269-5087<span name="x"></span><br></div><br><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Daniel Sober" <sober@cua.edu><br><b>To: </b>"Timothy Whitlatch" <whitey@jlab.org><br><b>Cc: </b>"Natalie Walford" <natalie@jlab.org>, "Alexander Somov" <somov@jlab.org>, "Giles Brown" <giles@jlab.org>, "Eugene Chudakov" <gen@jlab.org>, "Franz Klein" <KLEINF@cua.edu>, "Hall D beam working group" <halld-tagger@jlab.org><br><b>Sent: </b>Thursday, January 16, 2014 7:42:15 PM<br><b>Subject: </b>Analysis of tagger field map Configuration 2<br><br>
Plots of the tagger dipole field maps for Configuration 2 at 1.7 T,
1.5 T and 0.75 T have been added to the web page:<br>
<a>http:/faculty.cua.edu/sober/HallD/mapping</a><br>
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Everything looks good at the level of a few gauss. There is an
interesting small structure in the fringe field plotted vs Y with
a period of about 70 cm. Any ideas what it might be due to? (coil
clamps?, mapping frame?) In any case, it is too small to be
worrisome.<br>
<br>
Dan<br>
-- <br>
<font color="#ff0000"><i>Daniel Sober<br>
Professor<br>
Physics Department<br>
The Catholic University of America<br>
Washington, DC 20064<br>
Phone: (202) 319-5856, -5315<br>
E-mail: <a href="mailto:sober@cua.edu" target="_blank">sober@cua.edu</a></i></font><br>
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