BIC Injection Efficiency

Efficiency Data and Display

A first attempt at providing injection efficiency values is now in place. The following screen can be reached from the BIC Main or BIC Injection panel:

The Toroid readings are the two-second average of all pulses reaching TORO,PI11,6404 for HER and TORO,PI01,9404 for the LER. The efficiency is determined during injection by comparing bucket numbers and pulse ids from the toroid circular buffer with bucket numbers and pulse ids from the BIC dynamic calibration data. The change in current for each bucket in the BIC is compared to the TMIT measured for the same pulse. The smoothing used is

(old_value*beam_rate + new_value*#new_values)/(beam_rate+#new_values).

Since the number of new values is approximately the beam_rate, this provides just a little smoothing. The Toroid rate is the total measured rate.

The 1 Second Sum is the total undumpered TMIT through the toroid for one second. The 1 Second Efficiency is calculated by comparing that sum to the DI/DT from the DCCT. Since the DI/DT measurement time of each of these items is difficult to ascertain, this number will be meaningful only in a steady state of injection.

The next block of numbers represent data for the individual quanta per ring. The first three columns of data are familiar from the Calibration display; the fourth is a running average efficiency per quantum. Each item is calculated to be

(9*old_value + new_value)/10,

so it will change more slowly than the overall efficiency.

There are similar data for "Bucket Number Modulo 4". These are included to identify effects from the different Linac phasings used in each case.

Code Driving the Data

A batch job (ie: INJEFF) on MCC wakes up once a second at which time it calls the injection efficiency software (magshr:inject_eff.c). The uses can force this code to execute as a "one shot "by selecting the "Inject Eff." button on the EPICS DEV PANEL. A path to this button is given below:


The INJEFF standalone is spawned in the usual manner using WARMSLC from the MCC slcshr account. To determine if this batch job is running type the following command on an MCC.