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Why is this important?

Defining a “Golden” Closed Orbit (smoothed ‘n centered). beams doc 1540. Why is this important? We want average corrector current to be zero (not contribute to central trajectory) Reduce feed down from quad and sextupole in gradient magnet

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Why is this important?

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  1. Defining a “Golden” Closed Orbit (smoothed ‘n centered) beams doc 1540 • Why is this important? • We want average corrector current to be zero (not contribute to central trajectory) • Reduce feed down from quad and sextupole in gradient magnet • Determine true tune/chromaticity/coupling from Recycler permanent magnets • Match complex to true Recycler energy (w/o corrector contribution to average dipole field) • Reduce/eliminate dependency on DC magnetic elements, use magnet moves to reduce corrector strength (0.2A max) and install PM quad trims in phase trombone • Some statements • The Recycler central trajectory should be “as defined by the design lattice”. • The BPM’s were specified to lay on the central trajectory with dp/p as zero • The BPM’s/beam pipe were installed to centered on this central trajectory • The gradient magnets were installed with a specific sagatti (and longitudinal offset) correction to minimize feeddown and maximize aperture. Dave Johnson RR Dept Meeting

  2. Recycler BPM’s (do we trust them?) Results of global BPM survey 2001 +/- 1.6 mm • Factors in absolute BPM readings • Data for individual channels • Survey offset • Electrical center of plates • Electronic offset (cables+electronics) • Data for BPM type • Gain (mm/volt) • In process of verifying gains/offsets installed in front end • Rechecked lattice specification and survey technique • Magnets survey w/ Laser tracker (not shown) • Radial m = 0.001mm , s = 0.041 mm • V m = 0.002 mm, s = 0.022 mm • Roll m = -0.024mr , s = 0.201 mr • BPM/beam pipe optical survey • PLOTS to the right -> • Parallel offset to mini straight as defined by up/down stream gradient magnets/quads (using sagatti corrected offsets) Horizontal +/- 1 mm Vertical BPM Survey Offsets installed in front end O Dave Johnson RR Dept Meeting

  3. Our Current Operational Orbit rms 7.3 mm dp/p 0.0013 Xmax ~16 mm rms 1.38 mm aveg -.174mm Xmax ~16 mm After Stan’s vertical aperture scan Centering in physical aperture Dave Johnson RR Dept Meeting

  4. Corrector Settings for Current Operational Orbit -.305*73 ur/A = <22.3 ur> down .157*117 ur/A = <18.4 ur> inside Q corr / q dipole ~ 0.001 Dave Johnson RR Dept Meeting

  5. Smoothed* and Centered* Orbit • Centered Orbit by Rfreq • Smoothed using R50 • to select dipole/region for smooth • Not smoothed MI30 or MI60 • Avoided LEP corr (for now) • Fixed positions thru known apertures S Known Offsets • Closed injection to same eff rms 3.7 mm dp/p 0.0002 Xmax ~ 2 mm* • First pass at adj tunes • Admittance > 90 p • Coupling/chromaticity • NOT adjusted * First pass Dave Johnson RR Dept Meeting

  6. Recycler frequency change • RF freq: 52809500 -> 52809000 (only approximate now) • Revolution freq: reduced by ~0.85 Hz (89812.0748 Hz -> 89811.2244 Hz) • Revolution period: reduced by ~ 105 ps • dp/p (RR) = -0.0011 (h = -0.00851) • Impact on MI and complex • MI/complex energy reduced by ~ 8 Mev • Impact on RR BPM • only 89 kHz and narrow band • Minor impact • Schottkies • Mixdown frequencies • Stochastic Cooling • delay times between pickup and kicker change by ~20 ps • Electron Cooling • RF (low level wave forms) Dave Johnson RR Dept Meeting

  7. Corrector Currents for Smoothed Orbit .027*117 ur/A = <3.1 ur> inside Dave Johnson RR Dept Meeting

  8. Dynamic Aperture Working point (.425, .415) for this calculation Chromaticity = -2 units D dp/p = +0.003 25.5 mm Current central orbit dp/p +.0014 Typical dp/p(90%) +/-.0015 38.25 mm TM-2134 Meiqin, et.al. Dave Johnson RR Dept Meeting

  9. Working point Current Operating Point Qh ~ .414-.415 Qv ~.412 For x = -10, And dp/p ~.0015 Dv = +/-0.015 each plane (into 5th and 7th) x For x = -2, And dp/p ~.0015 Dv = +/-0.003 each plane (into 12th) Approx. tune spread for x = -10 shown on plot For dp/p of .0015 maximum x to avoid 5th and 7th order resonances Dave Johnson RR Dept Meeting

  10. Current Momentum Aperture 12/3/04 52808750 52810250 1250 Hz 52809500 2500 hz 3000hz dp/p>0 dn < 0 dp/p>0 dn > 0 Data taken by Stan… Extinguish points are 52805750 and 52813300 for momentum aperture of +/- about 3800 Hz. MI is not ramping for this data, H and V chromaticity is about -2.5 unit. Dave Johnson RR Dept Meeting

  11. Tunes Qh ~ .414 Qv ~ .415 Current Orbit Smoothed Orbit Currents: 0.427, 0.040, 0.489, -0.679, 0.172 Currents: 0.808, -0.239, 0.919, 0.016, 0.395 *No attempt to adjust coupling or chromaticity Trims: 2/half-cell @ 0.027 T/A PM quad: 4/half-cell @ .85 T  trims contribute 1.6% of focusing at 1 amp Dave Johnson RR Dept Meeting

  12. “Bare Machine” Tunes Design .425/.415 Measured Harm .4269 / .4022 Nov 30, 2004 Qh .4099 Qv .4310 January 11, 2005 VSA (uncorrected) Qh .4131 Qv .4393 Schottky Qh .4216 Qv .4349 Dave Johnson RR Dept Meeting

  13. Horizontal Admittance A = 0.02232*9.52/52 A > 90 p-mm-mr 21.7 mm 22.3 mm Operational orbit Smoothed orbit Dave Johnson RR Dept Meeting

  14. Our Current Operational Orbit gtr = 19.968 • Smoothed orbit with freq at 52809000 Hz • Increased freq back to 52809500 Hz • Orbit difference shows dp/p +0.0014 • Contribution +0.0011 from freq change Dp/p = -(1/h)Df/f Dp h=(1/gtr2 – 1/g2) h = -0.00851 Dave Johnson RR Dept Meeting

  15. What Needs to be Done • Include all offsets in BPM front end (in progress) • Smooth orbit (reduce average corrector strength) • Determine quad moves to reduce largest correctors (MI30 and MI60) • Adjust freq to get a zero dp/p with average corr current zero. • Investigate apertures in MI60 and MI30 • Center beam in phase trombone quads (H & V rms < .1mm / 5A) - Jan 11 • Adjust coupling (what’s the source) • Adjust chromaticity • Determine momentum aperture • Determine source of “bare machine” tune shift (DnX =-.0034 , Dny =+.02) • Measure sensitivity of lifetime due to tunes • Re-tune injection/extraction (may require adjustments to closed orbit/counter-wave in MI) • Re-adjust cooling/instrumentation to centered Recycler frequency • Match MI (and eventually the complex) to this new frequency/energy • Revisit MI ramp compensation Dave Johnson RR Dept Meeting

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