Dave Johnson July 12, 2010 NOvA/ANU Recycler Upgrades Review Optics, Apertures, and Operations Nova-doc 4930

Opening Statements 7/12/ Major activity over the last year has been further development of 3D model resolving interference issues, inclusion of beam pipe and vacuum components, and optimizing layout of elements. Optics Injection & Extraction transport lines can be described as FODO lattices with beta functions very similar to the Recycler and MI (i.e. maximum betas ~60 m or less) and vertical achromats. Recycler Abort line exists (will have a few modifications) Apertures We have examined all apertures (conservatively) and selected beam pipe or modified magnets to increase physical aperture. Operation Sensitivity to magnet errors and power supply regulation have been addresses in terms of impact on emittance growth. Ring closed orbit bumps and injection steering (POS/ANG) mults have been identified. Lattice matching techniques have been identified.

Recycler Injection 7/12/ Continuation of 8 GeV line FODO lattice using permanent magnet dipoles and quads with the addition of a vertical achromatic dogleg Recycler 8 Gev line V1 (switch) V2 (PDD) HBEND (35 mr) VLAM (MLA) K HKICK 848 MI MI QR85 3 QR85 2 PDDM H 102 Inj kicker lamb Vup Vdn Usual complement of BPM’s, Loss monitors, multiwires, and correction elements Only two power supplies required: Vertical switch magnet (ADCW) Injection Lambertson (MLAW) Powered trim quads (MQT) are included for matching (2 each location)

Recycler Extraction 7/12/ Vertical achromat between RR and MI (FODO lattice similar to MI) Design similar to existing R22 and R32 transport lines Permanent magnet quads (with electromagnet trims, MQT) Usual complement of BPM’s, Loss monitors, multiwires, and correction elements Only 3 Major power supplies required: Extraction Lambertson (MLAW) Vertical Dipoles (ADCW) Injection Lambertson(ILA) Powered trim quads (MQT) are included for matching(2 each location)

Recycler Abort Line (existing) 7/12/ Recycler abort line shares the beam absorber with the MI. Contains vacuum break downstream of the Lambertson (do we keep ?) Abort kicker double duty as pbar extraction kicker (pbar function will go away with Nova) NEW > Install gap clearing kickers so the beam in the injection gap is cleanly sent to the absorber 400 LAM402 KICKER LAM402 MI EnclosureWall Dump Assume ~5E13/1.33 sec Assume 2% in gap  1E12/1.3sec  1 kW Oct 2000 Recycler e-log RR MI NOvA doc 1529

Apertures 7/12/ Expect NOvA Booster batch intensity at approximately the same as today ~4E12/batch Current measured transverse emittance of beam from Booster (during slip stacking operation) is roughly  -mm-mr. 6  values of 21.6mm to 23mm and 10  values of 36mm to 38.4mm (for beta=60m) Minimum injection line physical apertures based upon a 10  beam envelope for a 25  -mm-mr emittance (   =60m) Minimum extraction line physical apertures based upon a 10  beam envelope for a 20  -mm-mr emittance (   =60m) Utilize same style of beam pipe that exists in the MI, RR, and 8 GeV. The ADC dipoles and the MLA Lambertsons are having new versions built with wider apertures. The main aperture constraints are at the injection extraction points (partially mitigated by creating a larger aperture Lambertson) Beam pipe choice considered installed magnet pole tip dimensions and design lattice functions (expected beam size). Details in following talks!

Apertures (2) 7/12/ A partial list of magnet and beam pipe apertures Magnet typeShapeHorVerHorVer [in] [mm] ADCW (could be 2x4” MR rect pipe)Special PDD (& PDS)Elliptical PDD_rolledElliptical PM Quad Pole tip MI beam pipeElliptical Recycelr beam pipeElliptical ILA (field region) existingrectangular MLA (field region) modifiedrectangular between dipoles (4”OD)Round ” round beam pipe (through PMQ)Round Gev bpm (4”OD)Round Recycler bpmelliptical Use at horizontal quad locations Use at vertical quad locations 10  of expected beam emittance is between 36 and 38 mm

Apertures Recycler Injection 7/12/ Provide for loss free transmission Expect emittance of  (history shows with large tails)-> clean up with MI8 collimation Would like to provide at least 1  for loss free steering Assume 99% in 6  -> use 10  with 25  beam Vertical aperture Min horizontal aperture

Apertures Recycler Extraction 7/12/ Maximum beta ~60m at quad locations (10  of 25  = 51.4mm) Vertical locations utilize 3” beam pipe (73mm) while horizontal locations use RR beam pipe (95mm) Recycler Extraction Lambertson Main Injector Injection Lambertson

Apertures Recycler Abort 7/12/ Abort line apertures OK for 10  of 14  H ellipse 4” round 24” round H V V V L V ellipse H ellipse V ellipse 4” round 24” round Horizontal aperture (red), vertical aperture (blue) 10  of 14  10  of 25  6  of 25  Need to perform aperture scan of abort line… schedule during start up

Operation 7/12/ Booster is assumed to be operational at 15 Hz Expected operational scenario Injection takes place during MI ramping (implications due to stray field on injection line) We expect all injections into Recycler will occur without interruption, but we will have the capability of interleaving injections at a 15 Hz level Gap clearing kicker at RR40 to clear any beam in injection gap before each injection Beam extracted without capture in 53Mhz (MI is at 8 GeV)

Operation (2) 7/12/ Tuning Instrumentation (use latest versions) 4 MW in injection 5MW in extraction line 4 MW in Recycler BPM’s Loss monitors (extra loss monitors around Lambertsons and switch magent Steering Define position and angle mults at Lambertson (approximately 2mm/amp on corrector for injection line) Define Recycler closed orbit bumps (both injection and extraction Lambertsons) Define MI closed orbit bumps around Lambertson Modify closure program to Recycler and MI injection Matching The permanent magnet gradients for both transport lines set to match into Recycler/MI with the trim quads set to zero Permanent magnet strength ~25 kG/m (2 or 3 at each location) 50 to 75 kG/m Trim quads (MQT) 0.9 kG/m/Amp with 2 at each location 1.8 kG/m which gives a 24 to 36% quad strength tuning range for 10 Amps Recycler lattice functions (  may be adjusted +/-25% with less than 6 amps on any trim quad Use profile matching for Recycler injection (MW) and TBT sigma matching for MI injection (IPM) with profile matching in both transport lines.

Summary 7/12/ The transfer line optics design were based upon existing transfer lines such as the 8 GeV line and RR22/32 (i.e we have experience designing and building permanent magnet lines and rings) The transfer line optics have been firm for well over two years. Beam line designers have worked closely with the Mechanical Support Department (Linda and Bill) to optimize locations of elements and specify appropriate beam pipe apertures. Plan to document existing Recycler abort aperture (upon start up) Power supply regulation requirements and tuning scenarios have been addressed (c.f. NOvA doc 4415,4563,4797, and 4761) Lattice Repository maintained as THE current source for lattice information.