Minutes from target meeting held September 1 2005 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2005/

a) Coupling of microwaves from wave guide soldered on the cavity wall were
discussed. The 8 mm wave guide now in use has seven 15 mm long tapered 
rectangular holes with sharp edge. The widths of the holes are 1.0 mm,
1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 4.0 mm and 7.5 mm. The holes are spaced
by 92.5 mm distance. This the same design used in the SMC microwave cavity.
Jaakko: irradiation of the target cells from only one side could cause 
inhomogeneous polarization in transverse direction. This with absorption of
microwaves into target material could explain the the different polarization 
values measured by different coils. Similar problems are handled in leaky 
wave guide antennas, where principles of geometrical optics can be applied. 

In the 8 mm wave guide the allowed modes at 70 GHz:

Mode	m	n	f_cutoff
TE	0 	1 	4.28286e+10
TE	1 	0 	2.14143e+10
TE,TM	1 	1 	4.78838e+10
TE	2 	0 	4.28286e+10
TE,TM	2 	1 	6.05687e+10
TE	3 	0 	6.42429e+10

b) Planning for 2006 was discussed. Kaori: with the new polarized target 
technical run is needed before physics data taking starts in June. Possible 
solution: skip field mapping at CERN and start immediately with dilution 
cryostat to see that the polarization of target material can be done in the 
new system. Backup solution is needed in case that there are too many problems
with the new target system.

c) Fabrice communicated the power requirements for the new magnet. Reply from 
Jaakko:

Here is list of power consumers on the platform. The circuit breaker
for solenoid is now 63 A, which is sufficient for the 27 A in your list.
The network needed for the cryo control rack is not specified. If the 
normal network is ok, O2 in EXD415/HN2 could be used after upgrading
the circuit breaker from 25 A to 32 A. If only one phase is enough
for the high power part of the cryo control rack then O9 is ready for use
with 40 A breaker.

For the operation safety of the magnet we need to consider if some power 
is needed from the diesel or UPS network. For the 25 A of 48 V it is 
better to discuss with CERN engineers. The 48 V 3 A is not a problem, I 
think we do not need O2 in ECJ415/HN2 anymore.  

The updated list of power consumers: 

http://wwwcompass.cern.ch/compass/detector/target/PTplatformpower


Comments from Fabrice:

I would like to comment your minutes concerning the planing for 2006:

I showed a preliminary planning of installation and test for the OD
magnet which does not include a full test of polarization before the
beam period. This of course has to be discussed and it is precisely why
I showed it.

Anyhow your personal comment for skipping the field map at CERN was not
discuss in this meeting but I only told you later that the field map at
CERN is needed due to the SM1 presence nearby OD magnet which requires a
dedicated trim coils setting specially considering the special G2
behaviour.

During this meeting I also pointed out the underestimation of the
waterflow rate for the stand-alone cooling unit for our power supplies.
This project in the responsibility of Stephane Platchkov. I contacted
the TS-CV service to inform them after Stephane's agreement.

You should also mention in you minutes that I asked for a final decision
concerning the control of the magnet+DR insulation vacuum system
(primary + diffusion pumps). This control unit (PLC) is rather old (~12
y.o) and according to Saclay could become a source of trouble. You said
that we will continue with it for the new magnet.

As I mentionned during the meeting (also not in the minutes) I took
contact with the electric services for updating the available power on
the plateforme (I did not only communicated the requires in the meeting
). This service is clearly overbooked for LHC and I try to clearly
define our request to shorter the delay. Thanks for your answer about
it.

Fabrice