BLTWG Meeting 11/16/2009

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  • Time: 11:00 EST
  • Place: EVO and ESNET (with telephone bridge)
  • Connecting: instructions are here
  • Present:

Agenda

  1. Update on the tagger resolution results, including multiple scattering] -- Alex
  2. Status report on microscope electronics -- Igor
  3. Status report on diamond development -- Richard
  4. Other progress reports -- others

Notes

comments by R. Jones on microscope resolution studies

  1. What happens when, as we agreed last week, the microscope is moved onto the focal plane and the fixed array and exit window are moved inward be the same amount? This should improve the resolution in the microscope a little, and at the same time reduce the size (and hence cost) of the vacuum chamber.
  2. So far we have only considered the focus in the dispersion (xz) plane. Where is the focal surface in the y direction? As I remember, the focal surface in the xz plane is mainly due to the dipole field and weakly depends on the quadrupole. However this is not true for the y-focus, which comes about entirely from the quadrupole field. Without the quad, the y-focal length is negative. Dan Sober once showed using TRANSPORT that the y-focal surface is not parallel to the x-focal plane, so the two can be made to cross anywhere in energy simply by dialing the strength of the quadrupole field. In Geant we can do this by placing an imaginary cut in the field map upstream of the dipole and rescaling the field there by some factor of order 1 such that the two focal planes cross in the region of the microscope. Now that we have changed the dipole optics, we need to repeat this exercise to optimize the y-resolution. The latest figures show that with the reduced pole width, the y-focus is no longer optimal.