Standard Beamline Quadrupole Specification
Below is the spec for a standard JLAB QP magnet. At 19amps, it can just make the field spec for the Hall D tagger.
|Bore||3.81 cm||1.5 in|
|Max B'l||75 kG||at 18 A (design current)|
|82 kG||at 19 A (depends on cable run)|
Response from G. Yang:
To get the proper vertical focusing for the 2D microscope readout at the focal plane at 3 GeV [9 GeV photons], the quadrople should have a field gradient of ~0.8 kG/cm and a length of 30.48 cm, or an integrated field gradient of 25 kG. If we intend to move the microscope to 5 GeV or higher-energy electron positions, the field gradient should only be slightly larger. So the capacity of the standard JLab QP magnet is fine.
Remaining questions are:
- The difference between the 25 kG requirement stated above and the 80 kG stated in the specification. Why was such a large margin built into the specification?
- How does cable run length control whether or not the quadrupole can reach 82 kG? Isn't that a power supply issue?
- What are the inner diameters of standard pipe sizes that fit through this bore? Can we find one that meets the 30±2 mm ID in the specification?