Notes - Instrumentation/beam physics meeting Feb 17, 2005 Agenda: 1) Tevatron phase detector - Bob Webber 2) synclite update - Randy 3) Tev emittance OAC update - Nate 4) Tev SBD averaged quantities - Bob Flora Action Items: 1)Phase detector: a) requirements/specs for phase detector suggested b) "real" talk in about 1 month c) Vladimir's questions/requests for phase detector 1) FTPs, especially around the glitch on the ramp. 2) what's the rms noise? 3) uncoalesced beam? 4) compare phase up ramp to calculation 2)Sync lite a) resolve whether or not sync lite proton emittances are "too small". (After the meeting Randy confirmed that there does seem to be a problem with the horizontal p emittance.) b) get sync lite pbar mirror in each store 3) TEV emittance OAC a) datalog/save in SDA Tev emittance OAC variables if not being done already. b) The OAC will change from MC SBD dp/p to AT SBD dp/p later. c) No coupled emittances for now d) Formal agreement next week on which lattice parameters to use for which stores. (Meeting to be arranged with Vladimir et al, Valeri, Vaia, instrumentation, Elliott, Tim) 4) Tev SBD a) datalog/save in SDA new SBD average average values if not done already b) document SBD variables Details: 1) Phase detector. Bob Webber Aisha is now in charge. Jean-Paul will become responsible from the Tev side. There will be a "proper" talk in about a month. Bob showed a block diagram and first results from bunch 14. The plots are in the instrumentation elog, along with some commentary. The device appears to be putting out sensible results and reveals some interesting structure at cogging and partway up the ramp. It tracks the SBD centroid motion but with an apparent gain difference. (Bob Flora said the SBD has a systematic error on the ramp.) This data is not averaged, but in the final system it will be averaged over 128 turns, which is small compared to synchrotron frequency. Bob doesn't think there is pbar contamination before the final collision cogging because of the stripline location. Over a long store the phase wanders by a few degrees that so far doesn't seem to correlate with anything, except possibly vertical position. Aisha has done lots of bench tests - hopefully that will be shown in her talk. The final system will have a circular buffer for catching instabilities. Jean urged that the requirements/specifications be written so they can be reviewed by the customers. Vladimir had some questions/comments: 1. Can it work on uncoalesced beam? The answer was a qualified yes. It can't be done bunch by bunch at 53 mhz. It will average over the train(?). A mode switch was part of the design and will probably be kept but not implemented right away. 2. What's the rms noise? 3. FFT of the raw signal - one can probably get the data at 720 hz via the MADC ftp. 4. He wants J-P to compare the phase up the ramp with calculation. Bob said he doesn't believe the absolute calibration. 5. FTP around the ramp glitch to see if its 60 hz? The system will use an OAC - Dennis is working with them on this. 2. Sync lite 1) Randy measured the gains from the input to the image intensifier to the final camera output and found a factor of 4 difference between the pbar path and the p path. This nicely explains the "missing" proton light. Randy believes the proton system is in good shape and believable including dispersion. Vladimir disputed this saying the synclite numbers are now way too small. He and Randy will look at the data again. Of course, flying the wires during the store is another check. For pbars, Randy did some measurements in regards to getting a signoff for moving the mirror in each store. Until that happens, the system is looking at body light. He showed 2-d images at the beginning and end of a long store. There is definite distortion, which could explain why the emittances go down instead of up. There is no easy way to focus the system when using body light and the simulation isn't setup to easily handle this situation, so Randy wants to wait and make the pbar system work on edge light. 3. FW OAC - Nate Bugs from last week have been fixed. A bug in the FW frontend dp/p calculation has been found and fixed. There are coding problems with respect to lattice parameters that Elliott reported fixed, or at least found. (Although I thought it had been resolved, there is apparently still uncertainty over which lattice functions to use for which stores. This will be resolved next week with a formal treaty.) We decided in the meeting to hold off on publishing the coupled emittances. 4. TEV SBD - Bob Flora The Tev SBD now provides running averages: = ( (n-1) + new ) / n where n = 10 n could be increased. Some simple cuts are applied? The names are the same as the regular ones, except they end in "A" instead of "S" My offer still stands - a prize to anyone who actually reads this far and tells me..