Comments on Beam Monitoring System Review
                           Dec 10, 2001

                   from   Bob Bernstein
                       ------------------------


1. Overall Remarks 
I was quite impressed with the muon monitoring effort. The purpose and 
scope of the system are well defined and the test runs and their analysis 
showed a committed and highly competent effort. The group should be praised 
for their excellent work at BNL. 

The hadron monitoring is not at the same level but they have made progress. 
I will detail some concerns below. 

Overall I am a bit concerned about the alignment of the system. Dropping down 
to the pit will introduce an error of a few mm. I think the system can be 
aligned with respect to the horn to about 5 mm. I have asked AMG to perform an 
analysis to determine how well the relative position of monitoring devices 
with respect to the horn can be determined. 

The environmental variables are not well controlled. Measurements need to be 
made as close as possible to the devices, not something 20 feet down the corridor. 
The temperature at the monitor and in the alcoves will vary and perhaps I missed 
it but I believe no data were shown about the variation, although the standard 
equations were trotted out. A measurement would be helpful. These will be 
important particularly during start-ups. It is more than likely that these are 
the times when the temperature of the enclosures will vary. 


2. Itemized suggestions, questions and concerns: 
(1) On the muon system: 
a) The ties between performance and physics goals have been well understood. Using 
the different alcoves to test different parts of the flux is a good idea and 
although it is not the final word in accuracy it serves a useful purpose for the 
cost and effort involved. 

b) The PIC’s ought to be able to handle the fluxes involved and the group has a 
convincing plateau curve and linearity analysis. Nice work! 

c) The calibration techniques seem adequate. Using a press fit is the right answer 
for the source holder. 

d) DAH promised to simulate damage to the front end of the target. I have personally 
seen damage to the front end of the E616/701 dichromatic target and have a picture 
of it in my desk. I think that is worth doing. 

(2) On the hadron system: 
a) Although significant progress has been made the physics goals are not as sharply 
defined as I would like. The use of the hadron monitoring to establish initial beam 
position is well thought out but after that I don’t see a convincing argument. 
b) The group presents a contradictory position. On the one hand the device is supposed 
to be worth building, but on the other it says that if something breaks it will not 
be fixed. Either it is worth having or not if it is then some plan for repair or 
replacement has to be worked out both for the pads and for the readout. 
c) The plateau curve is not satisfactory. I was not clear as to whether the success 
of the muon group implies that a plateau exists for the hadron group since the 
fluxes are so different. I was unimpressed by the argument that Kopp made that a 
plateau was unimportant. 
d) The radiation hardness of the system is not adequately defined. The group could 
not come up with a consistent statement of either the level required or the level 
achieved. Numbers varied over an order of magnitude from roughly a factor of two to 
twenty better than required but the simulations have effects from delta-rays which 
are only roughly approximated. Deltas and soft fuzz are notoriously difficult to 
simulate and I doubt I would believe anything to a factor of two. I am told a test 
at a reactor facility is possible and I believe this should be aggressively
pursued. 
e) The differences between PIC1 and 2 and the linearity analysis were still in a 
beginning stage. The student seems more than capable of doing the analysis but 
needs more time. He has clearly done some nice work. These analyses need to be 
understood at the same level as the ATF analysis. 

f) I didn't follow the discussion about how the response with time coupled into the 
beam structure and the ion drift time. Obviously if there is charge buildup this 
could be a big problem so this must be resolved as well.