Difference between revisions of "Photon Beam Design Requirements"
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# beam adjustable down to threshold of 0.1% nominal intensity for absolute normalization [6] | # beam adjustable down to threshold of 0.1% nominal intensity for absolute normalization [6] | ||
# continuous real-time monitoring of post-collimator beam spectrum [7] | # continuous real-time monitoring of post-collimator beam spectrum [7] | ||
− | # average polarization within coherent peak determined with accuracy ±2% absolute[7] | + | # average polarization within coherent peak determined with accuracy ±2% absolute [7] |
Revision as of 17:16, 29 January 2008
Global Specifications for the Hall D Photon Beam
- choice of photon energy in the range 8 - 12 GeV [1]
- duty factor >90% at 500 MHz beam pulse repetition rate [1]
- orientable diamond crystal bremsstrahlung radiator [2]
- peak linear polarization of 40% at 9 GeV with collimation [2,3]
- average polarization 36% in coherent peak 8.4 - 9.0 GeV [2,3]
- photon beam collimator with half-angle 22 μr [3]
- photon beam centered on collimator to within 3 μr [3]
- photons tagged with energy resolution better than 60 MeV (0.5%) within coherent peak [1,4,5]
- beam tagged with reduced resolution over extended range 3.0 - 11.4 GeV [4,6]
- complete tagger coverage in range 9.0 - 11.4 GeV with 1% resolution [6]
- absolute photon energy calibration better than ±30 MeV
- nominal operation at 10 MHz tagged photons in coherent peak after collimator [1,3]
- tagging rate 25 MHz within coherent peak at nominal intensity [5]
- tagger capable of operating at intensities up to 100 MHz in coherent peak after collimator [1,3,5]
- beam adjustable down to threshold of 0.1% nominal intensity for absolute normalization [6]
- continuous real-time monitoring of post-collimator beam spectrum [7]
- average polarization within coherent peak determined with accuracy ±2% absolute [7]