Status of Tevatron Chromatic Correction Sextupole Commissioning

Status of Tevatron Chromatic Correction Sextupole Commissioning Jerry Annala April 16, 2007 Motivation for Sextupole Modifications previously reported by Alex Valishev Improved Luminosity Lifetime

New working point Smaller tune footprint Eliminate 2nd order chromaticity Lower linear chromaticity? J. Annala Tevatron Chromatic Correction Sextupole Status 2

New Tevatron Working Point Currently operating between 4/7 and 3/5 with beam-beam = 0.02 To increase number of particles need more tune space WP near should allow 40% more! However, vicinity of half-integer increases sensitivity to quadrupole errors, especially chromatic

Moreover, large chromatic b-function is detrimental to beambeam effects even at present WP Work done by: Alex Valishev J. Annala Tevatron Chromatic Correction Sextupole Status 3 2nd Order Chromaticity J. Annala

Tevatron Chromatic Correction Sextupole Status 4 Sextupole Loop Schematic J. Annala Tevatron Chromatic Correction Sextupole Status 5 Implementation Plan

Switch to new PS in original polarity Run at same current as T:SF and T:SD Turn new circuits off and compensate with T:SF and T:SD. Run HEP stores this way. Reverse Polarity of half of the elements on the new circuits. Begin tuning up new circuits to reduce second order chromaticity.

J. Annala Tevatron Chromatic Correction Sextupole Status 6 Status Switched loads to new supplies in orginal polarity.

Polarity checked all elements with beam. Tuned up B2 drift at injection and snapback. Have begun tuning up the ramp and squeeze with new circuits running at zero amps. J. Annala Tevatron Chromatic Correction Sextupole Status 7 Vertical Orbits at start of study (Feb 28)

J. Annala Tevatron Chromatic Correction Sextupole Status 8 Smoothed Orbits through 800 GeV (April 6) J. Annala Tevatron Chromatic Correction Sextupole Status 9

Tunes on the ramp J. Annala Tevatron Chromatic Correction Sextupole Status 10 Before HEP store with new sextupoles at zero

Re-do orbits one more time Decouple two more slots on ramp Insure orbit is correct at a few special locations Run Proton only store on helix Do high intensity 12X0 Proton only store J. Annala Tevatron Chromatic Correction Sextupole Status 11 Correction of -function Chromaticity (Alex

Valishev) J. Annala Tevatron Chromatic Correction Sextupole Status 12