Beam Stability Instrumentation Test Plan
This plan is to utilize the beam time during the E91-016 experiment to fully test the instrumentation we have prepared for beam energy stability required by the HNSS experiment. Since E91-016 has not specific and restrictive energy and beam position stability requirement, the spokesperson has agreed to let us to operate our beam instrument full time. The following outlines the objectives and goals we are trying to accomplish by this test.
Fast Feedback system - This system will be operated in a full time base. Certain signals should considered to be put into data stream for detecting the possible reference energy shifting and the time of duration for such shift.
OTR - This system will be operated in a full time base. The central position and width as functions of time should be displayed all time. They should be in data stream also.
ARC Dipole NMR Probe - The field readout should be recorded in data stream and displayed as a function of time all time to monitor the field stability.
Thermal Couple - The relative temperature should be recorded in data stream and displayed as a function of time all time. This is to provide a reference for the B field measure in order to determine if the total integral of Bdl has been changed due to current fluctuation of the dipole power supply.
Fast Feedback Controlled by Hall C - This is the regular mode of operation for HNSS. We should test it in a long operation time base.
Fast Feedback Controlled by Hall A - This is an alternative operational mode for HNSS in case that the low beam current becomes an issue. It needs to be tested also in a long operational period to compare with the regular mode.
Fast Feedback Controlled by Hall C but Low Beam Current - This is to test if the Hall C fast feedback control can be operated at a low beam current like 0.5 micro-Amp. Due to the effect to E91-016 data taking, we may only test it for 30 minutes or setting test in the facility development time for couple of hours. For best utilize the time and minimize the impact to E91-016, we should prepare this test well before starting it.
(1) By what means we can confirm the beam stability;
(2) By what means we can detect and confirm a reference change of fast feed back, i.e. central beam energy shift due to whatever the reasons;
(3) Find a list of the most common reasons for such shift and what we should do to minimize them;
(4) What kind of collaborative actions we should take when such shift happens;
(5) How to incorporate the information from the ARC dipole B field and temperature monitoring;
(6) How frequent the fast feed back system break down and the common reasons;
(7) What procedure to bring it back and how much time it needs;
(8) If it cannot bring back quickly, what the options we can have and what action we should take when it happens;
(9) What collaborative procedures we should establish to ensure a stabilized operation of the beam stabilization instrument and a quick diagnose and decision when problem appears;
(10) What should be the procedure to change beam on target position without change ARC optics; and
(11) How frequently we run into a situation that the optics has to be changed in order to bring beam back down to Hall C and beam on target position as expected. This would give us an idea that how frequently we have to take kinematics calibration runs.
Information gathered above should eventually allow us to develop a workable protocol which experimentalists and operators will follow.