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Brief summary of Run #3 (29 July) and #4 (3-6 August)

Brief summary of Run #3 (29 July) and #4 (3-6 August). Shinji Machida o n behalf of the beam commissioning team ASTeC /STFC/RAL 9 August 2010. Injection orbit into septum. Established a way to measure ( x , x ’) at the entrance of septum.

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Brief summary of Run #3 (29 July) and #4 (3-6 August)

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  1. Brief summary ofRun #3 (29 July) and #4 (3-6 August) Shinji Machida on behalf of the beam commissioning team ASTeC/STFC/RAL 9 August 2010

  2. Injection orbit into septum • Established a way to measure (x, x’) at the entrance of septum. • Position at the last two quadrupole in the injection line (Q17, Q18) is within ~1 mm in horizontal, that is within error bar. • In vertical, a few mm depending on tuning upstream. • In vertical, steering before the septum (V-06) is adjusted to increase a beam in the ring.

  3. Septum mapping (1) • (x, x’) as a function of strength is reproduced. It is consistent with July data, although June data looks different. (x, x’) at entrance might be different in June. • For example, x’ vs septum setting below, • S1: 22 June • S2: 3 Aug • S3: 14 July • S4: ignore.

  4. Septum mapping (2) • (x, x’) at the exit of septum is not as designed. • Change of strength and rotation is not enough to get (x, x’) by Stephan or Scott. • Instead, David calculated kicker strength assuming (x, x’) given.

  5. Kicker calibration • Polarity of kicker 1 and 2 is determined. K1 kicks outward and K2 kicks inward. • Calibration between kicker setting voltage and CT current is measured.

  6. A beam in four sector • A beam went back through 4 sector with more reasonable settings. • QD/QF = 260/220 A, which should give 18.5 MeV/c equivalent beam. • Nominal kicker 1 and almost zero kicker 2, which is consistent with David’s calculation.

  7. Tune measurement • With nominal setting of QD/QF=260/220A, horizontal tune is 0.15-0.18, which is close to the design value 0.177 (hardedge) at 18.5 MeV/c. • Tune with +/-5%, 10% setting was not accurate. Later found out that continuous beam loss within 4 sector happened.

  8. Optics matching • Found that beam loss in the 4 sector can be reduced with the last 4 quadrupole setting in the injection line (Q15, 16, 17, 18). • Meaning that need better optics matching. • Both Yuri’s empirical setting and Jaroslaw’s calculation with MAD-X reduced beam loss.

  9. Time of flight • Measured BPM signal of E07-EBPM-01 and E23-EBPM-01 directly. • Signal is much lower than BPM in ALICE, which is strip line type. EMMA’s one is button. • With the scope we used, which is 10 GS (100 ps sampling), difficult to see change of ToF with various lattice setting. • 5 ps (max) per cell x 16 cell = 80 ps.

  10. Final remarks • “One” of EPICS BPM card seems working now. However, BPM data taking still relies on 7 cables, which gives 7 BPM planes (H or V). • Difficulty to expand momentum range seems mainly due to different (x, x’) from septum. • Overall, however, we understand EMMA much more in details. • Actual data is stored on http://www.astec.ac.uk/emmafiles/analysis/

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