Present: TB, RM, CT, MF, BF, GT, BT, HK, VZ, JK, KD, JvL,ZZ
and JC, RA (speakerphone)
B.Franklin: reports on spin flipper run. Typical running conditions were at low
current (<15 mA), no slits, no target. Stored currents only up to 80mA,
with flipper in. This was first extended test of compton over time. Observed a narrow
resonance for the flipper, consistent with the snake tune. After mapping of available
phase space, operation was: turn on dipole, ramp RF frequency, turn off dipole. Found
a spin-flip efficiency close to 100% for a beam polarization of ca 67 %. Compton
results very consistent. Error bar on polarization is ca 5 %, which has large
contribution from statistics. At that time Mott polarization measurement was 73 %
(scaled relative to previous measuraments) Then did spin flipper tests at high current:
large fraction of beam (up to 30 %) could be lost during a flip. This seems to relate
to the tune spread that intervenes at high current. Possibly can try a different flipper
tune that will interfere less the beam.
Also, we'll need to go to a bigger diameter ceramic pipe with tapered mesh to allow
better impedence matching and possibly higher stored currents. This poses no problem for
flipper RF power
H. Kolster: ABS flow reduction is consistent with misalignemt of nozzle/skimmer.
Operation with field on/off has been demonstrated however dissociator must
be kept on when field is ramping up. Tuning of MFT just started. Discusses putting back
a nozzle x,y position adjustment, including a z adjustment (z is distance to skimmer).
J. Kelsey: Installation of ABS will continue next week, expects no vacuum through tuesday.
After that, installing a left sector NC possible but needs OK from Wch people.
The second neutron wall will have to sit below beam height. Note, BL and BR neturon walls
will be (at best) at different distances from the target
J.v. Laan: CCR will need (night) shift time to figure out target holding field
T. Botto: Problems with BR neutrons solved (broken hv cables, missing trigger cabling,
broken software). Gain matching with cosmic in progress. Installed new analogue
adders (in the hall) and low attenuation Rg214 cables for further CC testing
-- ________________________________________________________________________________ Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124 research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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