1. Chicane and Bunch Spacing Scans
Joe Calvey
6/17/09 1 1 1

2. Chicane Scans We have chicane scan data at: 2 and 5 GeV 4ns and 8ns
4 ns plots for a train of 45 positron bunches, .75 mA/bunch
8 ns plots for a train of 45 positron bunches, 1 mA/bunch
Plots show collector 1 (edge) and collector 9 (center)‏ 2

3. 4ns, 2 GeV TiN, Collector 1 TiN, Collector 9 Al, Collector 13 3

4. 4ns, 5 GeV TiN, Collector 1 TiN, Collector 9 Al, Collector 1

5. 8ns, 2 GeV TiN, Collector 1 TiN, Collector 9 Al, Collector 15 5

6. 8ns, 2 GeV, detail TiN, Collector 1 TiN, Collector 9 Al, Collector 16 6

7. TiN
TiN, Detail Al
Al, Detail 7

8. 8ns, 5 GeV TiN, Collector 1 TiN, Collector 9 Al, Collector 1

9. Chicane Scan Observations
8 ns data has huge enhancement at n=20 resonance
n = 21 also big, but not much
Note: TiN RFA 3 (next to Al chamber) also sees some extra current there but TiN RFA 2 (not shown) does not
Electrons leaking from RFA 4?
5 GeV data has spike at low current
RFA efficiency issue?
Density higher in drift?

10. Large Bunch Spacing Energy Scans
Dominated by primary photoelectrons
43 bunches, 56ns separation, .8mA/bunch
2 GeV shown (we also have 5 GeV)‏
Data taken with all (22!) RFAs around ring
Chicane field = 860 Gauss

11. TiN Wiggler, Pole Center
Cu Wiggler, Pole Center
TiN Wiggler, Pole Center
Drift (downstream of wigglers)‏
Drift (upstream of wigglers)‏ 11

12. Dipole 13W Chicane RFA2 (TiN)‏ Chicane RFA3 (TiN)‏ Chicane RFA4 (Al)‏12

13. Energy Scans with Varying Bunch Spacing
We have data from all RFAs at 4, 8, 12, 16, and 20ns bunch spacing
In general bunch spacing does not seem to have a huge effect on RFA response
We have not examined this thoroughly
It does have an interesting effect on the center pole wiggler RFAs
Becomes more prominent with higher bunch currents
“Trampoline” effect?
Data shown is for a 45 bunch positron beam at mA/bunch, 5 GeV
Wiggler pole center RFA, center collector

14. “Trampoline” Effect?
4ns
8ns
12 ns
20 ns 14 14