RHIC CNI Polarimeter Operation Instructions

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Procedure

A.     Injection

1.      Target scan

·  If target scan is needed ( we don't need it for normal operation), use 1 bunch only for target scans.

·  Scan Blue & Yellow.

·        You get an emittance measurement for free.

2.      Polarization Measurements

·  Measure polarization in sweep mode with same beam you are going to ramp. The measurement can start as soon as one ring is filled.

·  When RHIC is ready for ramp, fill Blue & Yellow with desired bunches.

·  Events between 20-40 million are good enough. Note: you can only change number of events by velocity in this mode. Increase sweep velocity(in step of a few hundreds) if events are high and decrease sweep velocity if events are low.

·  Take Blue1 and Yellow2 with profile-by-sweep mode. If sqrt[B1*Y2] is less than 50%, do not ramp. Investigate polarization. Otherwise, ramp as soon as possible.

·  Check Analysis Summary. Dump analysis and measurement pages to elog.

B.     Beginning of store

1.      Polarization Measurements (waiting for low beam decay or successful collimation)

·  Events between 20-40 million are good enough. Note: you can only change number of events by velocity in this mode. Increase sweep velocity(in step of a few hundreds) if events are high and decrease sweep velocity if events are low.

·  Blue & Yellow, profile-by-sweep mode with both polarimeter2(first) and polarimeter1(second).

·  Check Analysis Summary. Dump analysis and measurement pages to elog.

C.     During store

1.      Polarization Measurements every 3 hours.

·  Events between 40-50 million are usually good enough. The actual goal is to get error bar of 2.5% and not too much smaller than that. Please adjust velocity to achieve that. You may need to increase the velocity during the store to maintain the similar error bars. Note: you can only change number of events by velocity in this mode. Increase sweep velocity (in step of a few hundreds) if events are high and decrease sweep velocity if events are low.

·  At the end of store, after taking profile by sweep mode, take fixed target measurements.

·  Check Analysis Summary. Dump analysis and measurement pages to elog.

D.     Emittance Measurement

1.      Operators use only the default targets to do emittance measurements when asked. Dump the pictures into elog.

2.      If the so-called "emittance calibration run" is required, call emittance fan Anatoli.

E.     Target Switch

1.      When a target is lost (indication would be no or very few events + no beam decay increase when target inserted), operators can switch to the backup target defined in the following table. This means that you are only needed (allowed) to switch target on the same axis (e.g. H1 to H2). For target operation beyond that, consult experts.

2.      To switch target, go to "TargetScan"tab. Make sure the default axis (horizontal or vertical) is selected. Select the desired target number. Proceed from there.

Polarimeter Targets

 

Tank

Blue 1

Blue 2

Yellow 1

Yellow 2

Default

H6

V6

none

H5

Backup

H6

V6

none

H2

 

 

 

General rules

0. One can not run downstream polarimeters (Blue2 and Yellow1) or upstream polarimeters (Blue1 and Yellow2) the same time. One can not run two polarimeters in the same ring either.

1. Leave blue2(yellow1) for horizontal targets, blue1(yellow2) for vertical targets(note: this could change in the future).
2. Target scan should be done with one bunch at injection. Do not do target scan at store.
3. Take profile by sweep measurement every two hours in store with 60 million events as limit. Events between 20-40 million are good enough. Increase sweep velocity if events are high and decrease sweep velocity if events are low.
4. The control of target, measurements are similar to last run. Details will be found in Operation wiki.
5. There is another wiki page maintained by polarimeter groupPolarimeter Group wiki.  

 

How-to Instruction (take blue as example):
From StartUp->RHIC->PolarControl(Blue)
Select TargetScans tab. Select direction tab (horizontal or vertical). Default is blue1 with horizontal, blue2 with vertical.
Select Target. Default is target1 for both blue1 and blue2(note: this could change in the future) .
Take target scan by click start. There may be a warning popup shown after the target scan. Click OK.
Select Polarization Measurements tab. Select Measurement type. For the ramp development period, Fixed target for injection and Profile by sweep for store. Click Data Run.

Call List
Overall operation: Dmitri Smirnov, Anatoli Zelenski, Bill Schmidke, Haixin Huang.
Application: Seth Nemesure, Jim Jamilkowski, Al Marusic
Polarimeter pc: Dmitri Smirnov

Troubleshooting Guide.