Highlights of the ATS MD part I (injection and ramp) … An 8h video game party carefully organized by Jorg et al. 1S. Fartoukh, LSWG 24/05/2011

First injection: beam1 captured and circulating (idem for beam2) S. Fartoukh, LSWG 24/05/20112 … starting from nominal injection pre-settings, which means that the CO correction of the nominal optics is already very local. 30 min. later: 0.15 mm r.m.s. closed orbit (crossing knobs off)

First tune measurement: Machine fully coupled but with a  Q min of only 0.06 w/o ANY correction, and then easily decoupled with the closest tune approach (down to or less) S. Fartoukh, LSWG 24/05/20113 The first reality touch in the video game  |C - | is given to be 0 in FPGA while the machine is fully coupled

S. Fartoukh, LSWG 24/05/20114 New ADT settings (phases) and <50 turns damping time at the first attempt First dump test … What is what, the beam or the target? A series of tests at 450 GeV (damper, dump, RF trims, OFB and QFB,…)

S. Fartoukh, LSWG 24/05/20115 A series of optics measurement at 450 GeV H and V dispersion:  No correction applied (but the right polarity of the 600A trims … and the 3% MQW ITF)  Dy of cm in the arcs, a factor of 4 to 6 below spec (good V orbit, quadrupole alignment, random a2 of the MB a factor of ~1.5 below initial spec & MB sorting on a2)  Dx of up to 50 cm in the arcs, still below spec. (60 cm) but why (see later)??

S. Fartoukh, LSWG 24/05/20116 Beta-beating:  No correction applied (but the right polarity of the 600A trims … and the 3% MQW ITF).  25-30% beta-beating, obviously dominated by the settings of the IR standalone quads.  Can IR3/7 (MQW) be re-optimized and the triplet ITF be redefined by combining these results with the ones of the nominal optics?.. Do not forget that up to 20 units ITF discrepancy were observed on the KEK Q2s when re-measured in the US?  While very small beta-beat is induced in the arcs (sorting of the SSS) why do we have a source of random b2 in the arcs creating a sizeable dispersion (see later)?

S. Fartoukh, LSWG 24/05/20117 The proof that the nominal optics has not been loaded by mistake (or that the video game is well-done)  New integer tunes 62/60 (instead of 64/59)

S. Fartoukh, LSWG 24/05/20118 …The ramp …. The first one fails (TCDQ interlock not masked). …. Then record 90 min. turn around time! …. An the second was a success with excellent life time, transmission of intensity, and no emittance growth.

S. Fartoukh, LSWG 24/05/20119 A series of optics measurement at 3.5 TeV Beta-beating:  No correction applied (3% removed for the MQWs).  IR contributions strongly reduced thanks to the accurate field model at 3.5 TeV, but the squeezed optics will require more as for the nom. optics (e.g. 1 units ITF accuracy in the triplet).  Certainly less than 10% coming from the arcs (b2 sorting of the SSSs).

S. Fartoukh, LSWG 24/05/ H and V spurious dispersion:  No correction applied (3% removed for the MQWs).  Dy still “perfect”  big gain of V aperture in the existing/new IT for the squeezed optics  Dx not improved (contrary to beta-beating??), looks random and not driven by the IRs:  Most likely interpretation: SSS sorting optimized w.r.t. beta-beating (  /2 pairs) and checking Dx a posteriori. Phasing by  the  /2 pairs would have minimized Dx but was found impractical during the production (too many hardware constraints after the assembly of the MQ cold mass).

Outlook and Next Steps Certainly a great success due to many factors (conception, magnet sorting, field model, feed-backs, beam diagnostics and measurement techniques, OP …).. But still the easy part (hopefully proved to be easy) The ATS MD part II: – Dry run of the IR1 and IR5 pre-squeeze to  * =1.2 m, and of the IR1 squeeze down to  * =30 cm. – MD with beam: injection/ramp/pre-squeeze with measurement and correction of the optics and chromatic aberrations. S. Fartoukh, LSWG 24/05/201111

Beam 3.5 TeV [mm] and Dispersion [m] Nominal orbit [m] with crossing scheme ( correction of H/V spurious dispersion with orbit bumps ) Tune vs. delta_p ( Q’ corrected to 2 units ) Montague functions ( W=1000 ↔   =0.001 ) IP1IP5 IP1 IP5