Difference between revisions of "How-to"

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(Magnets)
(Magnets)
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*For the Fall 2017 run, the SHMS magnets can be set by current from the desired momentum in [GeV]. From any computer, run:  
 
*For the Fall 2017 run, the SHMS magnets can be set by current from the desired momentum in [GeV]. From any computer, run:  
'''./getSHMS P '''
+
go_magnet_SHMS_current P
 
+
where P is the desired momentum in [GeV]. The formulas and program should be kept in sync with the [https://github.com/hszumila/field17 repository]. For optimal stability, all magnets should be put "on loop". This is done by first setting the polarity, then setting the magnet to a maximum current, and then ramping down to the desired current. The maximum currents for putting a magnet on loop are shown below:
+
  
 +
where P is the desired momentum in [GeV]. This will return the current that each SHMS magnet should be set to. The formulas and program are in sync with the [https://github.com/hszumila/field17 repository]. For precision physics data-taking, the magnets should be put "on loop". '''Turn off the beam prior to ramping the magnet and putting on loop'''. The procedure to put the magnet on loop is described here:
 +
Ensure beam is off.
 +
1. Select polarity for electrons or positrons in the magnet gui.
 +
2. Ramp each magnet to the maximum current (see table below for SHMS).
 +
3. Ramp each magnet down to its desired current (the output of go_magnet_SHMS_current).
 
{|border="1" align="center"
 
{|border="1" align="center"
 
! SHMS Magnet !!  Max current [A]
 
! SHMS Magnet !!  Max current [A]
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|}
 
|}
  
 
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If you need to change polarity, first ramp the magnet to 0 [A], and then you can change the polarity. After this change, you will need to ramp the magnet to maximum again.
 
+
  
 
*[[Spectrometer Magnets]]
 
*[[Spectrometer Magnets]]

Revision as of 17:59, 1 December 2017

NOTE: If you can't solve the problem in 1 hour you MUST then contact the Run Coordinator! (See also Experts on call)

How-to's

Magnets

  • Magnet screen is brought up on any hcdesk machine using
 % go_magnets
  • For the Fall 2017 run, the SHMS magnets can be set by current from the desired momentum in [GeV]. From any computer, run:
go_magnet_SHMS_current P

where P is the desired momentum in [GeV]. This will return the current that each SHMS magnet should be set to. The formulas and program are in sync with the repository. For precision physics data-taking, the magnets should be put "on loop". Turn off the beam prior to ramping the magnet and putting on loop. The procedure to put the magnet on loop is described here:

Ensure beam is off.
1. Select polarity for electrons or positrons in the magnet gui.
2. Ramp each magnet to the maximum current (see table below for SHMS).
3. Ramp each magnet down to its desired current (the output of go_magnet_SHMS_current). 
SHMS Magnet Max current [A]
HB 3600
Q1 2400
Q2 3660
Q3 2480
Dipole 3450

If you need to change polarity, first ramp the magnet to 0 [A], and then you can change the polarity. After this change, you will need to ramp the magnet to maximum again.

SHMS Detectors

HMS Detectors

Hall C target

Hall C target configuration for Spring 17 running

Legacy Documentation