T-980 Meeting (17 Dec 2008)
- Status of IHEP goniometer Nikolai Mokhov (Fermilab)
Final Mechanical drawings have been excepted.
Nikolai has been working on the final draft version of the accord bewteen IHEP and FNAL
and it is ready to be signed by both institutes.
Since FNAL did not want the VME part of the controls in the design there is some
money left over ~ $5k. This money will need to go for any mech modifications once the
goniometer arrives at FNAL and also for 2 additional laser angle measuring systems. The
goniometer should arrive ~ April from IHEP.
Analysis of E11 Flying Wire (low gain only) Satomi Shiraishi (Univ. of Chicago)
Satomi presented the first talk on using the flying wires at E11 to attempt to see
a channeled be profile from the crystal. This talk was dedicated to analysising the
low gain paddle to gain calibration for use and understanding of the high gain paddle.
Analysis of Dec 10, 2008 End of Store Study Valentina Previtali (Cern)
Valentina presented a 2nd round of the data analysis from the Dec 10, 2008 EOS beam study.
The talk was focused on 3 main subjects as a continuation of a couple of topics discussed
on Dec 15 meeting. The 3 topics were
1) analysis of the double peak.
2) Attempting to collimator V.R. beam
3)Comparison to W target
Noise on E0CH (discussion) All
There was a discussion about the noise on the E0CH if this is real noise resulting
in a real horizontal shift or if it is just electronics noise due to tempreture in the
crate. It is believed that the noise is not a real hor motion.
E1 counters not working (discussion) All
There is some thinking that the E1 counters have not been quite working correctly
since the power outage. Rick was going to check the timing to make sure it was ok.
He checked the timing on Dec 19 and found it ok.
Completed work in the tunnel All
There was a feeling the E0pin was not working, so during a short access Todd replaced
all the IC's in the PIN. The result was that it did not change the behavior. It is beleived
now that the pin is working correctly but the effects be be real. It could have to do with
when the E03H collimator was retracted back to make D49H the leading edge.
Also during the access, a new counter at the pin location was installed and cabled. Rick
will still have to terminated the cable upstairs but this can be done any time.
Discussion on Summary of Studies and plan for next studies
Dean attempted to summarize all the contributions for the day by a comparison
of the 2005 and 2008 data sets for the "O" shaped crystal. There are a couple of
similarities between the data sets and still some questions.
1)Compare width of channel 2005 to 2008. This is very similar.
2)Compare hieght of V.R region 2005 to 2008. This appears to be different and is mostly like
related to large miscut angle or beam conditions.
3) Missing displacement at E03H has now been solved. The crystal angle of the maximum
number of particles channeled is not the same as the crystal angle the produces the
maximum displacement at E03H. Again this is most likely related to large miscut
angle of the crystal.
The data for different crystal angle vs. E03H scans is becoming more complete. We
do not seem to get displacements fro the V.R. region bigger than -140 urad. This appears
to have something to do with scattering from amorphous Si possibly due to miscut angle.
4) Comparison of the 2005 to 2008 D49 target and crystal seems also to be very similar. It
appears at a glance that collimating the channeled beam vs. scattering from W is better well
behaved most likely due to the fact that particles lost during channeling are removed on first turn
while scattered particle can have paths that are lost in detectors before lost on a collimator.
5) Need better understanding of 2005 collimator settings during the scans that produce limiting apertures.
Dean will attempt to retrieve this information.
6) There is a need to overlay the 2005 and 2008 data in all aspects. We will begin doing this.
7) One of the most important tasks to confirm is the reliability of reproducing the angle for
channeling. So far this has been very good. Even cases where the pin has not seen channeling,
putting the crystal angle back to -240urad has yielded channeling. This is very encouraging.
8) What is needed now is to continue to move forward to see if we can collimator channeled beam
at the Beginning of store with all of its automated glory. To accomplish this it would be helpful to
take another EOS and only auto place the crystal and collimators and then look at results.
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