Difference between revisions of "Standard Beamline Quadrupole Specification"

From GlueXWiki
Jump to: navigation, search
 
(One intermediate revision by the same user not shown)
Line 8: Line 8:
  
 
<i>Response from G. Yang:</i><br>
 
<i>Response from G. Yang:</i><br>
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 kGs/cm and a length of 30.48 cm.  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.
+
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:
 
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?
 
# 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&plusmn;2 mm ID in the specification?
 
# What are the inner diameters of standard pipe sizes that fit through this bore?  Can we find one that meets the 30&plusmn;2 mm ID in the specification?

Latest revision as of 16:04, 21 January 2008

Below is the spec for a standard JLAB QP magnet. At 19amps, it can just make the field spec for the Hall D tagger.

Bore3.81 cm1.5 in
Length30.48 cm 
Max B'l75 kGat 18 A (design current)
 82 kGat 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:

  1. 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?
  2. How does cable run length control whether or not the quadrupole can reach 82 kG? Isn't that a power supply issue?
  3. 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?