May 03, 2018

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Original Moller Polarimeter Page

Moller ELog

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Meeting ID 388 466 836

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1. Talk on Moller DAQ -Roman P. 1

2. GEANT4 simulation update -Eric title

3. GEANT3 simulation update -Bill H.slides

4. Discussion of Kerr activities


Only got to discussion of items 1 and 3 before 2:00 PM when moderator (D. Jones) had to end call for another meeting. Suggestion is for future meetings to be unmoderated so that they can continue in the absence of the moderator

Discussion of Moller DAQ. Old scalar system currently installed in Hall and operable but showing signs of possible radiation damage (need to clarify what this means...are there periodic crashes or should we expect elements to gradually break down as they reach the end of their lifetimes?). Can operate old DAQ as high as 1kHz flip rate so fine for PREX which will be at 240Hz. Work ongoing in test lab on new FADC system. JLab computing is working on issues with the current firmware and the acquisition software. Still need an analyzer built for the new system. With someone working on testing the new system with pulse generators in the test lab we might be ready to install and use with real pulses in about 2 months. However, Roman is only available due to VISA length of stay regulations for another two weeks. After this he will have to stay out of the US for at least 6 weeks at which point he could return for a maximum of 6 months. An immediate return after 6 weeks would not allow him to be onsite for PREX.

We need to identify someone to pick up the FADC testing soon. Instructions for operating the the DAQ are here.

Discussion of TOSCA model. We need a magnetic calculation of the quads and dipole in the Moller polarimeter. Sasha has begun working on a TOSCA simulation. He currently has a TOSCA model of the dipole that is ready for GEANT4. He has had issues implementing it into the GEANT3 simulation. Information on the magnets can be found here. Q1, the first quad, is new and was designed by JLab and added for the 12 GeV upgrade. The information needed to build a TOSCA model for Q1 is in hand. Q2-Q4 came from Los Alamos and less information is available for them. However, Q3 and Q4 are similar enough in specifications to Q1 that as a first step Sasha says he will simply implement them as identical. Q2 is quite different and will have to handled separately. There is not a clear path forward yet for modeling Q2. Sasha will continue working in the background on this project, but anyone with spare cycles is encouraged to join him.

GEANT3 Bill Henry has been working on the old G3 simulation trying to find optimal quad settings as a function of beam energy. He showed preliminary results for 2.2 GeV.