Beam Position scan to pin down He3 cell center

NEXT
Make New Entry, Make Followup Entry

User name Jin Huang

Log entry time 07:50:43 on January 23, 2009

Entry number 257404

This entry is a followup to: 257391

keyword=Beam Position scan to pin down He3 cell center

A BPM position scan is performed between 4:43Am and 5:19AM. The purpose of the test is to find the center position of the cell relative to EPICS read back of BPM. The conclusions are

The center of the cell is BPMA = (-1.3, 2.5); BPMB = (0.8, 2.5)
We have +-3mm clearance from cell wall on all directions with 3x4 raster (9mm from wall to wall, beam tail+tilting effect eat away ~10mm of clearance)
My beam tuning in the beginning of Jan run is only .4mm away from center.

Raw Data

The scan is performed with max raster 5x4mm (6x6 MCC) by

Spot++ confirming not hitting cell wall. Mark norminal trigger rate
Scan on BPMX untill reach both cell wall (tell by trigger rate). Keeping BPMA_X-BPMB_X = -0.5mm (might not be optimal difference)
Center X, scan BPMYs, Keeping BPMA_Y = BPMB_Y (might not be optimal difference)
Center Y

Scan ID	BPM A X	BPMA Y	BPMB X	BPMB Y	T1/10000	T3/100	Average X (mm)	Average Y (mm)	T1*T3(1M/s^2)
1	-1.022	2.175	-0.405	2.216	2.324	2.95	-0.7135	2.1955	6.8558
3	-0.5	2.175	0	2.216	2.3	2.9	-0.25	2.1955	6.67
4	0	2.175	0.5	2.216	2.4	2.9	0.25	2.1955	6.96
5	0.3	2.175	0.8	2.216	2.5	3.5	0.55	2.1955	8.75
6	0	2.175	-0.6	2.216	2.3	3	-0.3	2.1955	6.9
7	-1.8	2.175	-1.38	2.216	2.3	3	-1.59	2.1955	6.9
8	-3	2.175	-2.4	2.216	2.6	3.7	-2.7	2.1955	9.62
9	-1.3	2.175	-0.8	2.216	2.2	2.8	-1.05	2.1955	6.16
10	-1.3	1	-0.8	1	2.3	3.1	-1.05	1	7.13
11	-1.3	0	-0.8	0	2.5	3.4	-1.05	0	8.5
12	-1.3	3	-0.8	3	2.3	2.9	-1.05	3	6.67
13	-1.3	4	-0.8	4	2.3	2.9	-1.05	4	6.67
14	-1.3	5	-0.8	5	2.5	3.4	-1.05	5	8.5
15	-1.3	2.5	-0.8	2.5	2.3	2.9	-1.05	2.5	6.67
2	0.62	2.175	1.6	2.216	17	133	1.11	2.1955	2261

Scan Plots + Fitting

A copy of this log entry has been emailed to: jpchen

trigger rate vs BPMX

trigger rate vs BPMY