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Status of the Beams Division. John Marriner 15 October 2001. FNAL Accelerator Complex. Run II Luminosity Goals. The luminosity goal for Run IIa is 2 fb -1 Peak luminosity up to 2x10 32 cm - 2 sec - 1 Switch to 103 bunches at 1x10 32 cm - 2 sec - 1 Length of Run IIa is about 2 years
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Status of the Beams Division John Marriner 15 October 2001
Run II Luminosity Goals • The luminosity goal for Run IIa is 2 fb-1 • Peak luminosity up to 2x1032 cm-2sec-1 • Switch to 103 bunches at 1x1032 cm-2sec-1 • Length of Run IIa is about 2 years • The luminosity goal for Run IIa+Run IIb is 15 fb-1 • Increase antiproton intensity by 2-3 • Peak luminosity up to 5x1032 cm-2sec-1 • 103 bunch operation • Length of Run IIb is about 4 years
Run IIa • Going slowly, but not unreasonably so. • Need to be careful that our effort is well-focused. • Commissioning the Recycler is a key problem, and the purpose of current shutdown. • All the accelerators require extensive work. • 132 nsec bunch spacing requires new hardware and extensive commissioning time.
Proton Source • Maintain reliability in the face of increased demand and deteriorating hardware • Improve ion source (2x intensity, smaller emittance) • Reduce Booster beam loss • Operate Booster at 15 Hz
Main Injector • Pbar production OK • Fixed target operation needs development • Coalescing efficiency • Recycler commissioning
Recycler • Status • Aperture (20p mm-mrad?) • Vacuum (ion pump test) • Diagnostics, RF, feedback need work • Magnetic shielding now OK? • Cooling OK? • Purpose of the shut down • Alignment • Correction magnets & PS • Magnetic shielding
Tevatron • Minimize beam loss & emittance growth • Increase beam intensity • 132 nsec bunch spacing (crossing angle) • Beam-Beam effects are a key
7 rf bucket Bunch Spacing & Crossing Angles • A crossing angle is required for 132 nsec spacing but is not required for 396 nsec. • We have a plan for the implemented the crossing angle that requires 3 or 4 new electrostatic separators. • There is a luminosity penalty for introducing the crossing angle - about a factor of 2 in initial luminosity compared to zero crossing angle with the same bunch parameters • There are uncertainties in the dynamics of the beam-beam interaction with this mode of operation
Antiproton Source • Stacking at high stack rates with large stacks • Slightly larger core emittance • Pbar production rep rate to 1.5 sec • More protons on target • Cooling • Stack tail • Core • Beam lines acceptance and matching
Beam Physics • Identify & study key Run II issues • Foster communication • Future projects • Run seminars
External Beams • SY120 • NuMI • MiniBoone • CKM beam
Run IIb Upgrades • The major strategy is to increase the number of antiprotons • To some extent, this is the only strategy: collisions at the interaction regions are a major loss mechanism for antiprotons • We are also attempting to compensate beam-beam tune shifts
Luminosity Formula • The major luminosity limitations are • The number of antiprotons () • The proton beam brightness (Np/p) • F<1
More Antiprotons More protons on the antiproton target Slip stacking (~1.8 x) Proton beam sweeping Better antiproton collection efficiency Lithium lens gradient (~1.5 x) AP2-Debuncher aperture increases (~1.5 x) Better cooling Debuncher cooling bandwidth increase Accumulator Stacktail Profile Accumulator Core bandwidth increase Electron cooling in the Recycler
Slip Stacking • Reproduced MR results with MI • Need to push high intensity beam • Beam loading compensation is the key
Slip Stacking Booster Batch 1 Booster Batch 2 RF Bucket 1 RF Bucket 2 Final RF Bucket RF Phase Space Cartoon
Slip Stacking Experimentin the Main Ring beam current (dc) rf voltage fanback beam current at 53 MHz
Lithium Lens Gradient Predictions Measured Yield
Antiproton Aperture Increases Largest gain if aperture is increased in regions upstream of the first stage of stochastic cooling AP2 transfer line Debuncher The goal is to increase the aperture in both planes from 25p mm-mrad to 40 p mm-mrad Beam based alignment of all magnetic elements requires new instrumentation motorized quads Physical aperture increases such as replacing beam pipe in Debuncher dipoles with curved beam pipe
Electron Cooling TEV Beam-Beam Compensation Lithium Lens development R&D program on diffusion bonding for solid lens BINP liquid lithium lens R&D continues Start program on outside company building solid lens Finish beam-sweeping Build 1 house of prototype Debuncher BPM system AP5 Lattice designAP3/AP1/P3/P2 redesign Build 10 moveable quad stands for the Debuncher FY01 Activities for Run IIb
FY01 Activities for Run IIb • Revive Slip-Stacking Low Level Electronics in Main Injector & repeat low intensity slip stacking experiments • Include Mode 1 in MI beam loading compensation
Difficulties in Meeting Run IIa & Run IIb Goals • We need to finish the Run IIb upgrades before the LHC turns on. • As a consequence (and in contrast to previous collider upgrades) the Run IIb upgrades must be designed, fabricated, and commisioned while we are still concentrating on achieving the Run IIa luminosity goals. • We continue to have substantial commitments to fixed target experiments (NuMI, MiniBoone, 120 GeV test beams, and R&D for the separated kaon beam). • Our plan requires a significant increase in BD manpower for Run IIb.
More People • Systems Departments & Beam Physics • Controls & Instrumentation • Engineering & Tech Support
Electron Cooling • Pelletron procured, commissioned. • Recirculation tests in progress. • Beam tests planned for this year. • Will initiate AIP for construction of final resting place for Pelletron.
Fermilab Electron CoolingR&D Project High-voltage column with grading hoops partially removed to show the accelerating tube (right) and the charging chains (far center). 5 MV Pelletron installed
Pelletron HV Conditioning and Regulation Conditioning process of the gun-side accelerating tube. Blue – radiation under the tank, red - gun ion pump current (mA), Green - terminal voltage. Time axis: 30 min/div. Max. voltage: 4.66 MV. Terminal voltage in a regulation regime: 500 V/div, 1 min/div. Required voltage for the Recycler cooling: 4.36 MV.
Beam-Beam Compensation • Prototype lens constructed. • Require operational experience to proceed with 2nd lens.
MiniBoone • Detector AIP nearly complete. • Beam line AIP nearing completion. • Special equipment (horn, PS) progressing well. • We want to finish construction next fiscal year (2002) and begin operations .
NuMI • New baseline • Beamline design • Loss • Reliability • Pointing? • Successful horn tests
A0 Photo-Injector • Collaboration with NIU now in place • Program advisory committee has been formed • Experiments in progress • Photo-Injector properties • Flat beams • Plasma acceleration
CKM • CKM has been granted stage 1 approval by the director on the advice of the PAC. • We are designing the superconducting deflecting cavities to be used in the beam line. • We are building a prototype system. • We are working on the beam line design.
BTeV • BTeV has been granted stage 1 approval by the director on the advice of the PAC. • The idea is that the experiment would run at C0 area. Colliding beams at C0 and B0/D0 would be mutually exclusive. • The laboratory intends to obtain “line item” funding for this project. • We are working on the C0 insertion design.