Parity Checks

In the process of editing and updating this page. Please contact Juliette Mammei crowder@jlab.org with questions or suggestions.

PREX Main<< Information for Shift Takers << Shift Checklist

In general, you can try to search for things in JMenu (next to the magnifying glass, where compton is written in Figure 1) to see if they will come up. The instructions below tell you one way to navigate through the menus to get to the desired screen (there may be other ways to get there).

Shift Checklist Instructions: Check whether the IHWP is IN or OUT and record its state. Check whether the Wien Flip State Settings is FLIP RIGHT or FLIP LEFT and record its state. For the rest of the variables, consult the table below (for IHWP OUT consult values on left column, for IHWP IN consult values on right column) and verify the the present settings are consistent with the table by marking "OK" or "NOT OK" in the shift checklist.

For detailed instructions on how to check each parity variable, see below.

Table 1 - List of the correct settings for Insertable Half Wave Plate (IHWP) IN and OUT.

Variable	IHWPin	IHWPout
RHWP	1532	1532
Flip State	FLIP-RIGHT OR FLIP-LEFT	FLIP-RIGHT OR FLIP-LEFT
VWien Angle	+88° OR -89.9°	+88° OR -89.9°
Solenoid Angle	86.91°	86.91°
HWien Angle	-15.5°	-15.5°
PC ON/OFF	ON	ON
V PITA	371 ± 1000 counts	-638 ± 1000 counts
V L/4	12670	12670
V aposU	1509	889
V aposV	337	-552
V dposV	0	0
V dposU	0	0
HallA IA	42570	26046
HallB IA	37286	29353
HallC IA	25881 ± 1000 counts	42264 ± 1000 counts

Figure 1 - Main JMenu window.

Figure 2 - PGUN Main window in JMenu.

Figure 3 - Spin Controls window.

Figure 4 - RTP cell window.

Figure 5 - Parity Controls window.

• Insertable half-wave plate (IHWP) Setting (IN or OUT)
  • In JMenu, mouse over "Injector" (see Figure 1)
  • In the dropdown menu, choose "GUN/Laser"
  • From there, choose "PGUN Main"
  • The setting is indicated by the depressed button (see Figure 2, very bottom left corner, it is OUT in this figure)
• Rotatable half-wave plate (RHWP) setting (value like 1532)
  • Right next to the IHWP box in the PGUN window is the set value of the RHWP (1532 in Figure 1)

• Wien settings (FLIP RIGHT or LEFT, or LONG)
  • From JMenu, mouse over "Injector"
  • In the dropdown menu, choose "Spin", then "Spin Controls"
  • The FLIP LEFT or RIGHT or Longitudinal (see Figure 3, very top - middle region, it is "Longitudinal" in this figure)
• Vertical Wien Angle (degrees)
  • The variable is "VWienAngle"
  • Find it at the bottom of the left box of the spin controls window
  • The value is -0.00 in Figure 3
• Solenoid angle (degrees)
  • The variable is "Phi_FG"
  • Find it at the bottom of the middle box of the spin controls window
  • The value is 86.901 in Figure 3
• Horizontal Wien Angle (degrees)
  • The variable is HWienAngle
  • Find it at the bottom of the right box of the spin controls window
  • The value is -0.00 in Figure 3

• RTP settings
  • From JMenu, in search frame, type "RTP"
  • In the dropdown menu, choose "RTP cell"
  • See Figure 4 for example.
  • The ON/OFF button is in the pink region on the top right
• Main RTP Cell ON/OFF
  • This should always be ON
  • The voltage values are in the light purple region on the right
• VL/4 (counts)
  • The variable is in Figure 4
  • The value is always 12670 as in Figure 4.
  • It should always be the case that VL/4=VL/41=VL/42
• VPITA (counts)
  • The variable is in Figure 4
  • The value should be fluctuating by a few hundred counts
  • It should always be the case that "VPITA"="VPITA,1"="VPITA,2"
• VaPos,U(counts)
  • The variable is in Figure 4
• VaPos,V(counts)
  • The variable is in Figure 4
• VdPos,U(counts)
  • The variable should always be 0 and is 0 in Figure 4.
• VdPos,V(counts)
  • The variable should always be 0 and is 0 in Figure 4.

• IA settings
  • From JMenu, in the search frame, type "Parity"
  • In the dropdown menu, choose "Parity Controls"
  • The IA settings for the 3 halls are in the bottom half of the screen in the tan, grey, and light purple sections
• HALL A:IA
  • The Variable is "HallA IA voltage"
  • It is located in the bottom left tan region in the blue boxes next to "COUNTS READ" under DAC03
  • DAC03, DAC04,DAC05,DAC06 should all read identical values
• HALL B:IA
  • The Variable is "HallB IA voltage"
  • It is located in the bottom center grey region in the blue boxes next to "COUNTS READ" under DAC07
  • DAC07, DAC08,DAC09,DAC10 should all read identical values
• HALL C:IA
  • The Variable is "HallC IA voltage"
  • It is located in the bottom right light purple region in the blue boxes next to "COUNTS READ" under DAC11
  • DAC11, DAC12,DAC13,DAC14 should all read identical values and should be fluctuating

Next in checklist >> Left Arm Checks