Minutes from weekly target meeting held 28th of June 2002 in 892

a) Kaori checked the operation of the new beam interlock CIL-PTM-B4B5 by 
stopping the field rotation at 10 A of dipole current. The currents to bending
magnets B4 and B5 were ok. No HV trip in RICH was observed.

b) The Liverpool Q-meter diode output from coil #3 is now connected to channel
#5 in ADC card. This allows to determine possible dispersive phase corrections
to the NMR signals.

c) Yuri simulated the effect of changing NMR coil inductance to the Q-meter
response. This effect could arise through mutual inductive coupling between
the coils and/or with some other loop connected to the thermometers. He also
estimated error from wrong phase tuning. Jaakko pointed out that Gerhard
tuned the Q-meters using the enhanced NMR signals in highly polarised material.
To get symmetric NMR signal with no dispersion, it is sometimes necessary
to be little off resonance in the Q-meter tuning, i.e. the base line parabola
is not necessarily in the centre of sweep window. The thermometers TTH2,
TTH4 and TTH7 are permanently grounded this summer and disconnected from
the AVS bridges.

d) Our summer student Ture got his PC working with Linux during the weekend. 
He followed the CERN safety course on Friday and got also a visitors film 
badge.  

e) Fabrice ordered LN2 for the following week in advance. After the
field rotation of the night shift, the trim PSU 326 did not give current any
more to the corresponding trim coil. The problem was in the "tiroir 
inversion". Jaakko solved this problem in the afternoon by changing latch 
relay inside the box (one of the contacts had melted, more details 
available from Naoki). New spare relay was ordered on Monday from Radio 
Spares. 

f) Jaakko said that LN2 dewar with electrical level meter has to be prepared
before the LN2 is filled into it from the truck. The level meter and
the inlet/outlet valve system on the top part has to be removed, so that
it can be filled in the normal way. Do not fill it or let somebody else to
fill it from the outlet keeping the exhaust valve open. This procedure is
too risky, because the safety valves may freeze. After connecting a new
LN2 dewar to the LN2 trap, check that the tubing does not start to freeze
when the manual valve of the dewar is opened. If there is freezing, the leak
in this line has to fixed first. Usually the reason is leaking metallic
joint. 

g) In the GLB the transverse spin physics program for this summer was 
discussed. The planning was to do microwave polarisation reversal around
7 - 8 August. The transverse mode data would then be taken before and after
this reversal. More details need to be discussed in the weekly COMPASS 
meetings.