Forgot your password?
Experiment - 8Pi - Tuning Tips
through the slits & collimator --TA, Feb. 2011 & corrected by JA
1. Tune the beam to ILE1A:FC1. Beam at ILE1A:RPM1 should be centered and roughly symmetric (see Figures 1, 2); (RPMs' reference file 2009.12.02.13:41:51.snap, OLIS-->8PI reference tune 091202_1400.snapios8pi [Mike Trinczek]). For ILE1A:XCB1 through ILE1A:Q10, set quads, benders, and slits to theoretical values and steering to zero-effect.
Figure 1: ILE1A (8PI) Beam Envelope showing rough RPM location Figure 2: ILE1A:RPM1 reference (elog 2009-12-02 14:12:28)
2. Open ILE1A:(X/Y)SLIT4A device pages. Send the beam to ILE1A:FC6. Aim for 100% Transmission (Tx) while centering the beam on & focusing it through the 5mm slits using ILE1A:XCB1->ILE1A:B4. Occasionally check ILE1A:RPMs(4/4A) (compare w/ Figures 3, 4) and verify that the profiles roughly match the expected envelope in Figure 1. It is OK to take ILE1A:Q1->ILE1A:Q4, as well as downstream quads, well off of theory. We don't expect those quads to stay right at theory because they are needed to 'match' the beam into 8pi.
Figure 3: ILE1A:RPM4 reference (elog 2009-12-02 14:12:28) Figure 4: ILE1A:RPM4A reference (elog 2009-12-02 14:12:28)
3. Ensure ILE1A:IV8 is open (if not, consult w/ experiment before opening). Open ILE1A:(X/Y)SLIT8 device pages. Send the beam to ILE1A:FC10. Aim for 100% Tx while centering the beam on & focusing it through the 13.2/11mm slits. Ideally, attempt to achieve this using only devices past ILE1A:(X/Y)SLIT4A. Occasionally check RPM8 (comparing w/ Figure 5) and verify that the profiles roughly match the expected envelope (Figure 1).
Figure 5: ILE1A:RPM8 (elog 2009-12-02 14:12:28)
4. Open ILE1A:COL12D & ILE1A:FC12 device pages. Confirm w/ experiment that ILE1A:FC12 is installed (removable cup), and that the cable for ILE1A:COL12D is connected (to read collimator current). Remove all upstream Faraday cups. Aim for max Tx while minimizing beam on the collimator, ideally using only devices past ILE1A:(X/Y)SLIT8.
5. Save the tune and check the ILE1A:FC12/FC1 Tx.
6. Revisit all ILE1A optics while watching the current on ILE1A:FC12. Iterate through them and maximize transmission from ILE1A:FC1 to ILE1A:FC12. If no improvements are possible, restore the save tune in (5.) above. If improvements are made, re-save the tune.
7. Document the tune (RPM'S, snapshot, etc).
