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Robert Michaels HAMC Hall A Analysis Workshop 09 C HAMC = Hall A Monte Carlo ROOT / C++ Design Somewhat like SAMC & genercone For HRS only. Uses LeRose transfer functions. Abstract classes: Experiment, Physics, Target Used by HAPPEX-3, PVDIS, and PREX. A. Deur, V. SulkosyD. Lhuillier, K. Paschke, B. Moffit Contributors: Dustin McNulty, Diancheng Wang or matrices, or Guido fcn.

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Robert Michaels HAMC Hall A Analysis Workshop 09 C Applications of HAMC Estimate Rates, Asymmetry, Sensitivity to Physics Design Collimator, Sieve, A_T detector. Design integrating detector & focus at detector Estimate sensitivities to beam parameters. Effects of radiative corrections, acceptance.

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Robert Michaels HAMC Hall A Analysis Workshop 09 HAMC Events Generate beam Target position uniformly sampled (raster option) Fill solid angle uniformly Cross-section computed for rates and weighting Asymmetry computed (for Parity Expts) Energy losses (Brehms and dE/dX) with MC methods Multiple Scattering Transport to various points in HRS and Septum Acceptance cuts applied at apertures Event Analysis on accepted events. Objects

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Robert Michaels HAMC Hall A Analysis Workshop 09 Transport Polynomials from John LeRose (same)

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Robert Michaels HAMC Hall A Analysis Workshop 09 Transport Polynomials (part 2) thanks, John LeRose Was used to check where electrons scrape; e.g. not in iron of dipole ?

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Robert Michaels HAMC Hall A Analysis Workshop 09 Cross Section Input Shown here for Lead

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Robert Michaels HAMC Hall A Analysis Workshop 09 Does HAMC work ? Yes, well enough for our goals. A problem: Radiative tail out to high loss is underestimated. Use effective target size to adjust (reduce) predicted rates.

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Robert Michaels HAMC Hall A Analysis Workshop 09 Comparing HAMC to Real Data This was done for HAPPEX-1, HAPPEX-2, and a Lead test run

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Robert Michaels HAMC Hall A Analysis Workshop 09 More Comparisons …

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Robert Michaels HAMC Hall A Analysis Workshop 09 A Lead Test run in 2005 (using old septum magnet)

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Robert Michaels HAMC Hall A Analysis Workshop 09 PREX Design : At 5 0 the Optimal FOM is at 1.05 GeV (+/- 0.05) 1% @ ~1 GeV RNRN

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Robert Michaels HAMC Hall A Analysis Workshop 09 Collimator at entrance to spectrometer Be degrader Insertable blocker to block Be Aligned in spectrometers to define identical Left / Right scattering angles as well as good up / down symmetry A_T hole Suppressing A_T systematics Paul Souder

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Robert Michaels HAMC Hall A Analysis Workshop 09 HAMC Design of Collimator All Events Collimator

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Robert Michaels HAMC Hall A Analysis Workshop 09 Events from A_T hole (Be plug) Main detector A_T detector Measures horizontal A_T systematic. (Vertical is measured from Left/Right spectrometers) Thanks: Dustin McNulty Krishna Kumar Paul Souder

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Robert Michaels HAMC Hall A Analysis Workshop 09 Sieve Slit Design Few more holes drilled to improve coverage and accuracy.

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Robert Michaels HAMC Hall A Analysis Workshop 09 Acceptance Function Analysis for Workshops and Future Publication Credit: C. J. Horowitz

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Robert Michaels HAMC Hall A Analysis Workshop 09 C Conclusions re: HAMC Reproduces data -- well enough. Has aided in several estimates and design efforts. Underestimates radiative losses -- maybe another MC better ? Restricted to HRS and single-arm at the moment. Might be easy to make a coincidence base class. The GOOD The BAD

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