View source for SBS spot++ (beam size verification)

[https://hallaweb.jlab.org/wiki/index.php/Shift_How-To Back to How-To]

To image the target or raster size by plotting the hits as a function of raster x and y current, we do the following:

== Taking the Data ==

* Take a CODA run under the following conditions.  Make a post to the HALOG with the title "spot++ run XYZ" with XYZ = run number.   
** Beam current: 5--10 uA 
** Raster size: Check run plan
** Target: Carbon Hole 
** BigBite setting: Check run plan
** Super BigBite setting: Check run plan
* Take data until at least 50k events have been reached for sufficient statistics 
* Stop the CODA run

== Analyzing the Data == 
* Log into one of the aonl machines (e.g., a-onl@aonl1).
* Run the command: spot_SBS [run-no], where run-no is the CODA run number of the raster scan. If omitted, the most recent run will be analyzed. 
* After a few moments, the plots will pop up 
* When prompted, enter y on the command line to post the plots to the HALOG (n does not post to the HALOG).

=== Plot Descriptions ===
* '''BPMA y vs x:''' Shows the beam location at BPM A
* '''BPMA x:''' Shows the number of events at each x value in BPM A
* '''BPMA y:''' Shows the number of events at each y value in BPM A
* '''BPMB y vs x, BPMB x, BPMB y:''' Same as above but for BPM B
* '''Beam at target y vs x, …x, …y:''' Same as above for at the target
* '''BPMA Antenna 1, 2, 3, 4:''' Signal at the four wires of BPM A, one for X+, X-, Y+, Y-, respectively
* '''BPMB Antenna 1, 2, 3, 4:''' Same as above but for BPM B