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Recycler/MI Momentum Apertures

Recycler/MI Momentum Apertures. Recycler Orbits/ Aperture Main Injecter Aperture Collimation Additional Thoughts. Current Recycler Orbits/Dispersion. LAM402. LAM214. LAM328. Recycler elliptical beam pipe aperture 3.75” x 1.75” ID  +/- 47.625mm x +/- 22.22mm.

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Recycler/MI Momentum Apertures

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  1. Recycler/MI Momentum Apertures • Recycler Orbits/ Aperture • Main Injecter Aperture • Collimation • Additional Thoughts SNuMI Meeting Beams doc 2172

  2. Current Recycler Orbits/Dispersion LAM402 LAM214 LAM328 • Recycler elliptical beam pipe aperture • 3.75” x 1.75” ID •  +/- 47.625mm x +/- 22.22mm Admittance ~ pa2/bmax Ah ~128 mm-mr (norm 390p) Av ~ 28 mm-mr (norm 83 p) with bmax ~55 Measured Dispersion 214 ~ 1.7m , 328 ~ 2m Scraper measurements -> ~70 p (H) and ~40 p(V) SNuMI Meeting Beams doc 2172

  3. 95.25mm 75mm dia 44.44mm e circ ext/inj 50 mm sq 5 mm offset/ Center septum 5 mm septum 20 mm+6s ~38-40mm Recycler Lambertson flange layout Effective Circulating Aperture at Lambertson end ~ +/-24.5 mm Aperture scan LAM328 stored protons, unknown emittance under-estimating aperture Radial outside Recycler centerline SNuMI Meeting Beams doc 2172

  4. Recycler Momentum Aperture Measurement Measured with 8E10 pbars, debunched, Dp/p (full) ~ .44 % (initial)e ~ 1.3 p Qx .413, Qy .419 Setting: Cx -2.0, Cy -1.6 nx .458 ny .476 Cx ~6 units 2.4 khz. Dp/p .0036 Dn -.02 Full aperture nom x +0.75 – 0.65% zero x +/- 0.775% Initial distribution Zero loss nom x +0.36 - 0.2% zero x +/- 0.37% Zero chromaticity Z Restore nom. Chrom. 0.3% For dispersion ~ 2m Dx ~ +/- 16 mm motion dp/p ~1.55% Measurement by: Dan, Dieter, Martin SNuMI Meeting Beams doc 2172

  5. Main Injector Momentum Aperture Measurement Use K103 to ping beam at injection MI Lambertsons straight sections-> small dispersion (not MOM aperture limit) Strong coupling: dp/p 1.07 dp/p .64% 52811400 hz -4200 hz +6200 hz SNuMI Meeting Beams doc 2172

  6. 1st inj 2nd inj capture df=1300 hz df = -1300 hz 3 1 2 Aperture Issues • -Booster transverse emittance -> high intensity MI vertical aperture filled • -RR/MI aperture ratio: Horizontal 0.8 and Vertical 0.875 • -For Coupled lattice transverse aperture limited by vertical • (50mm MI and 44mm RR) • Main Injector slip stacking • Bucket offset during slip stacking • Df(2) = - 1300 hz -> Dp ~ - 26 MeV @ 2nd inj • Df(3) = +/- 650 hz -> Dp ~ +/- 13MeV @ capture • Bucket height +/- 7 Mev • Maximum energy offset • Dp(2) = - 33 MeV @ 2nd inj -> dp/p = -0.37% • Dp(3) = +/- 16.5 MeV @ capture -> dp/p = +/- 0.185% • Un-captured beam losses (at acceleration) 2.5% to 5% Transverse loss @ LM521A (vertical) LM608F (last Lamb) on NuMI only cycle SNuMI Meeting Beams doc 2172

  7. Beam Power and Collimation Given 12 * 5E12 protons/1.49 sec: Booster average beam power at 8 Gev is 64 kW (10 hz) MI (or Recycler) average beam power at 8 Gev is 51.5 kW MI average beam power at 120 GeV is 773 kW Compare MI8, Booster, and MI collimators assuming acceleration loss in MI SNuMI Meeting Beams doc 2172

  8. Assumptions for Recycler Modifications • Removal: • Stochastic cooling tanks (kickers and pickups); • Present aperture-limiting transfer lines to and from the MI. •  aperture limited by Lambertson not beamline • Installation: • New 8-GeV injection line from the Booster; • concept design at MI10 (from Q848): V Lamb/ H kicker • New 8-GeV extraction line to the MI; •  assume located in MI30 ? • New full-turn (10-µs flattop) extraction kicker; • assume horizontal kicker - rise time not critical < 1.6 us • what about an injection kicker ? use vertical K103? • New collimation system; transverse or momentum? • Possibly new beam abort line or capability; why ?already exists • 53 MHz RF system. Only needed if slip-stacking • Upgrades: • BPM system upgrade to 53 MHz bunch structure; Only needed if slip-stacking • Instability damper; • Low-level RF system; • Beam loss monitoring system. Is this in addition to MI loss monitors? Additional Comments • Removal of electron cooling insert • Redesign 30 straight FODO or momentum collimation and transfer line from Recycler to MI • MI may have collimation system in MI30 ??? From: Proton Study Group (Recycling the Recycler) SNuMI Meeting Beams doc 2172

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