[Halld-pid-upgrade] PID Upgrade Meeting Tomorrow

[Baptiste Guegan]

Dear all,

I would like to summarize the situation on our side:

_We have set the length of the prototype to be 1m long. That will allow us to study a full arc, with some reflections on the side.
_We have contacted a company that will make the surface coating of the 3 segment mirrors (which is still the best compromise with the last simulation results). The coating is about 1000$. The reflectivity depends on the surface quality (polishing), and we are trying to know what kind of quality we could get at Bates.
_We have corrected a bug in the analysis code, and we have now to reprocess the simulations to get the new results. At first sight, it seems that this error (PMT QE was not properly implemented) does not affect too much the main results.
_right now, the plan is to use water (deionized, that gets the best transmittance). This, as you know, is not a trivial thing to produce. Fortunately, I contacted Jerry that told me that the whole purification system is available at SLAC. We would "just" need to replace some filters. That would save us between 20 to 30k $. :)
_We are trying to gather some information about the reactivity of the deionized water with the aluminum substrate and the coating. But the answer will be probably that we don't know. We will probably need to make a real test and to put a small sample of the mirror inside a deionized water bath.

This is the status on our side. Does anybody want to present something else for tomorrow? Should we have the meeting?

Thanks
Baptiste

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