---------------------notes on 12july02 meeting------------------------ ---------------------ODR/Transition radiation------------------------- Interest is in single slit to measure ODR and DR and TR by closing slit. Incoherent diffraction rad also considering double slit for direct measurement of emittance (csorna) looking at angular dist to measure xverse size (xverse size spec is still needed). Applicable under 5GeV (above this level, it's possible that the distribution angle gets too small). This is a single shot measurement (on single bunch). There are concerns with wakefields created by doing this measurement. coherent diffraction rad measure longitudinal looking at frequency distribution. applicable at all energies Estimated 10um resolution (meets 1/10th bunch size requirement). concerns with wakefields. Steve suggests that Vanderbilt should reproduce or borrow/help-develop the planned NIU detector. ---------------------NIU transition rad------------------------------ Discussed coherent part in meeting, but proposal also discusses monitoring diffraction and synchrotron. Plan to build a multichannel far IR interferometer to do single bunch measurements (single shot). What are the specs on "live time window" or minimum bunch spacing that this can handle. Mirage detectors might replace the existing detectors (some of us don't know what mirage detectors are). ---------------------Electro-optic----------------------------------- Vanderbilt, NIU Needs some way to meet the nominal 10um resolution goal. Wakefields may be an issue. NIU proposes to build a low imedepance vac. chamber to house the EO xtal. Vanderbilt proposes a better detection scheme in which they use an external polarizer as an analyzer, allowing them to measure zero output for zero beam. beam measurements would be made both at fermilab and Vanderbilt. Court said he would start with existing laser, but that pulses are too long/monochromatic to meet resolution goal. Bill will look into whether existing Vanderbilt TiS lasers can be upgraded to meet resolution goal of 100um (330fs). ----------------------Laser Wires------------------------------------- Hartill and JAE expressed interest, but the general conclusion was that there are not currently enough people/resources to compete with existing efforts. However, we will keep this option open for the future -----------------------other ideas discussed-------------------------- beam halo monitoring firing particle beams (i.e. laser wire w/ electrons instead of laser). Don Talked about using the ions produced by residual gas and detecting them using a microchannel plate. ----------------measurement of x-ray synch rad directly---------------- x-ray Synchrotron radiation measurement directly. Focusing with Fresnel zone plate or glancing optics and imaging with a ccd. Could this measure a single bunch (i.e. can you gate on a single bunch (though you should have plenty of flux)). Do we need any specialized technology to gate in this time window. Exists an effort on this by someone at Tokyo (reported by H. Hayano at LC02). see www.slac-conf.stanford.edu/lc02/wg1/WG1_Hayano_H.pdf Both Jim Alexander and Jesse Ernst expressed interest in looking into this technique -----------------misc----------------------------------------------- Longitudinal res needs to be specified in terms of the 110um bunch length of the NLC. --------------------------------------------------------------------