Optics, Apertures, and Operations

Dave JohnsonJuly 12, 2010NOvA/ANU Recycler Upgrades ReviewOptics, Apertures, and OperationsNova-doc 4930Opening Statements7/12/20102dOpticsInjection & 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.AperturesdOperationd

Recycler Injection7/12/20103Continuation of 8 GeV line FODO lattice using permanent magnet dipoles and quads with the addition of a vertical achromatic dogleg847101103Recycler8 Gev line100850102104V1 (switch)V2 (PDD)HBEND (35 mr)VLAM (MLA)KHKICK848MI8849852851103102MIQR853QR852PDDM

H102Inj kickerlambVupVdnUsual complement of BPMs, Loss monitors, multiwires, and correction elementsOnly two power supplies required:Vertical switch magnet (ADCW)Injection Lambertson (MLAW) Powered trim quads (MQT) are included for matching.

Recycler Extraction7/12/20104Vertical 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 BPMs, Loss monitors, multiwires, and correction elementsOnly 3 power supplies required:Extraction Lambertson (MLAW)Vertical Dipoles (ADCW)Injection Lambertson(ILA)Powered trim quads (MQT) are included for matching.Recycler Abort Line (existing)7/12/20105Recycler 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

LAM402KICKERLAM402MI EnclosureWallDump4025Assume ~5E13/1.33 secAssume 2% in gap1E12/1.3sec 1 kW

Oct 2000Recycler e-logRRMIApertures7/12/20106Expect NOvA Booster batch intensity at approximately the same as today ~4E12/batchCurrent measured transverse emittance of beam from Booster (during slip stacking operation) is roughly 12-14 p-mm-mr. 6s values of 21.6mm to 23mm and 10s values of 36mm to 38.4mm (for beta=60m)Minimum injection line physical apertures based upon a 10s beam envelope for a 25 p-mm-mr emittance (s=5.14mm @b=60m)Minimum extraction line physical apertures based upon a 10s beam envelope for a 20 p-mm-mr emittance (s=4.6mm@b=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)7/12/20107A partial list of magnet and beam pipe apertures Magnet typeShapeHorVerHorVer[in][in][mm][mm]ADCW (could be 2x4 MR rect pipe)Special1.885.051124PDD (& PDS)Elliptical3.81.7596.544.5PDD_rolledElliptical1.753.844.596.5PM Quad Pole tip3.28 83.3 MI beam pipeElliptical4.62.011751Recycelr beam pipeElliptical3.81.89544ILA (field region) existingrectangular2.012.044305MLA (field region) modifiedrectangular2.04.751120between dipoles (4OD)Round3.883.8897973 round beam pipe (through PMQ)Round2.882.8873.273.28Gev bpm (4OD)Round 3.883.889797Recycler bpmelliptical3.81.7596.544.5Use at horizontal quad locations Use at vertical quad locationsApertures Recycler Injection7/12/20108Provide for loss free transmissionExpect emittance of 12-14 p (history shows with large tails)-> clean up with MI8 collimationWould like to provide at least 1 s for loss free steeringAssume 99% in 6s -> use 10s with 25p beam

Vertical apertureMin horizontal apertureApertures Recycler Extraction7/12/20109Maximum beta ~60m at quad locations (10s of 25p = 51.4mm)Vertical locations utilize 3 beam pipe (73mm) while horizontal locations use RR beam pipe (95mm)

Recycler Extraction LambertsonMain Injector Injection LambertsonApertures Recycler Abort7/12/201010Abort line apertures OK for 10s of 14p

H ellipse4 round24 roundHVVVLV ellipse

H ellipseV ellipse4 round24 roundHorizontal aperture (red), vertical aperture (blue)10s of 14p10s of 25p6s of 25pNeed to perform aperture scanof abort line schedule during start upOperation7/12/201011Booster is assumed to be operational at 15 HzExpected operational scenarioInjection 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 levelGap clearing kicker at RR40 to clear any beam in injection gap before each injectionBeam extracted without capture in 53Mhz (MI is at 8 GeV)Tuning Instrumentation4 MW in beam lines4 MW in RecyclerBPMsLoss monitors (extra loss monitors around Lambertsons and switch magentSteeringDefine 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 LambertsonModify closure program to Recycler and MI injectionMatchingThe permanent magnet gradients for both transport lines set to match into Recycler/MI with the trim quads set to zeroPermanent magnet strength ~25 kG/m (2 or 3 at each location) 50 to 75 kG/mTrim 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 AmpsRecycler lattice functions (b,a) 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.

Summary7/12/201012The 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 aperturePower supply regulation requirements and tuning scenarios have been addressed