Fermilab Proton Driver

Keith Gollwitzer

Accelerator Division

Fermilab

IDS-NF 8th Plenary Meeting Apr 18-20, 2012

Gollwitzer -- 8th IDS-NF Meeting 2

Outline• Project X Summary• Review of Task Force

– Project X Upgrades– Accumulation & Compressor Rings

April 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 3

Project X Goals Mission Elements

• Provide a neutrino beam for long baseline neutrino oscillation experiments based on a capability of targeting at least 2 MW on proton beam power at any energy between 60-120 GeV.

• Provide MW-class, multi-GeV, proton beams supporting multiple kaon, muon and neutrino based precision experiments. Simultaneous operations of the rare processes and neutrino programs are required.

• Provide a path toward a muon source for possible future Neutrino Factory and/or Muon Collider.

• Provide Options for implementing a program of Standard Model tests with nuclei and/or nuclear energy applications.

April 19, 2012

Project X Cartoon

April 19, 2012 Gollwitzer -- 8th IDS-NF Meeting 4

Gollwitzer -- 8th IDS-NF Meeting 5

Project X Summary• CW Linac will support average beam current

of 1 mA to 3 GeV• Pulsed Linac (3-8 GeV) will have a ~5% duty

factor operating at 10 Hz• Possible 8 GeV beam power of 320 kW

• Programmable Chopper System (part of H- source) will provide appropriate bunch structure for the linac experiments as well as fill the appropriate part of the RF buckets in the accumulating Recycler Ring

April 19, 2012

6Gollwitzer -- 8th IDS-NF Meeting

Desired Project X Siting

April 19, 2012

7Gollwitzer -- 8th IDS-NF Meeting

Desired Project X Siting

April 19, 2012

Main Injector & Recycler

3 GeV CW Linac

3-8 GeV PulsedLinac

3 GeV Experiments

8 GeV Transfer Line

Tevatron Tunnel

Gollwitzer -- 8th IDS-NF Meeting 8

Neutrino Factory• Upgrade Project X

– 4 MW at 8 GeV• Increase particles per linac bunch• Increase pulsed linac duty factor

• Repackage linac beam for ~50 Hz delivery– Accumulator Ring

• Collect linac beam into bunches

– Compressor Ring• Narrow bunches to <= 3 ns

– Single Bunch Transfer/Extraction

April 19, 2012

Neutrino Factory Layout

April 19, 2012 Gollwitzer -- 8th IDS-NF Meeting 9

Accumulator Ring

Compressor Ring

4MW Target

????

??

Gollwitzer -- 8th IDS-NF Meeting 10

Task Force• Fermilab Management established a group to

identify the upgrade path from Project X and look into feasibility of providing the desired 4MW beam

• Agreed on Project X upgrade numbers– Increase to 5 mA average current– Increase pulse linac duty factor to 10% at 15Hz

• Outlined options/limitations– Striping– Accumulator and Compressor Rings– Final Focus

April 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 11

Project X Upgrade Path• Front End (more particles per bunch)

– Project X ion source will be capable of 15mA• Initial run at 5 ma• NF era would run at 10mA

– LEBT, RFQ, MEBT are being designed for the higher current

• Beam chopping system absorber is being redesigned for NF

• CW Linac (average current 1mA to 5mA)– Retuning of RF couplers for better efficiency for NF– Collimation and beam absorber are being

redesigned for the higher currentApril 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 12

Project X Upgrade Path• Pulsed Linac (5% to 10% &10 Hz to 15 Hz)

– More RF power• Upgrade to 125 kW per cavity

– Upgrade of couplers• Power goes from 2 kW to 15 kW

– More cryo capicity

• Conventional Facilities– More water cooling– Building space

• More cryo equipment• More Klystrons

April 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 13

Neutrino Factory Operation Scenario

• Task force has considered 15Hz pulsed linac versus 50Hz desired for NF

• In Accumulator, will run h=9 (or 12) RF system.• Front end chopper will be synchronized to

send 50% of the 10mA beam (5mA average in CW linac) to be captured by the Accumulator RF

• 3 bunches will be removed at a time to the Compressor: effectively 45 Hz (or 60Hz)

• Compressor ring bunches are extracted to form bunch train to NF target

April 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 14

Rings Work• Many people contributed ideas, concerns,

calculations for Accumulator and Compressor• Requirements

– Stability (better for η<0)• Below transition

– Space charge– Bunching

• Most “advance”– FODO lattice (D Neuffer)

• γT ≈ νx (high tune for Cr)

– Flexible Momentum Compaction (Y Alexahin)• αp can be tuned• More flexible correction

April 19, 2012

Fp

pcn

ZeI pn

peak

2

2

B

rN

N

ppSC 2

%95,2

3

15Gollwitzer -- 8th IDS-NF Meeting

Accumulator FODO

April 19, 2012

Parameter Symbol Value UnitCircumference C 292 m

FODO cells L, NC, φ 11.2, 20, 90

m

Dipole params L, B 4.0, 1.25 m, T

Quad params L, B’ 0.8, 8.0 m, T/m

βmax,ηmax βmax,ηmax18.0, 3.5 m

transitions αp, γt0.038, 4.52

tunes νx, νy 5.44, 5.30

rf voltage Vrf, frf 4kV, 4MHz

• Simple FODO lattice (72º)– Large dispersion – Linear lattice– Missing magnet

dispersion suppressor

16Gollwitzer -- 8th IDS-NF Meeting

Compressor FODO

April 19, 2012

Parameter Symbol Value UnitCircumference C 292 m

FODO cells L, NC 5.6, 42, 90 mDipole params L, B 1.6, 1.4 m, T

Quad params L, B’ 0.6, 27 m, T/m

βmax,ηmax βmax,ηmax9.3, 0.56 m

transitions αp, γt -0.03, 11.1

tunes νx, νy13.45,12.72

• Simple FODO lattice (90º)– ~ <2T magnets– Smaller dispersion

17Gollwitzer -- 8th IDS-NF Meeting

Accumulator FMC

April 19, 2012

• Baseline cell is 30m long– 6 quads, 4 dipoles– Can change dispersion

function with Q center

– Negative Dx gives large negative – αp

• 8 cells + 2 ~29m straight sections308m ring– Dispersion is straight

sections– Room for inj./extr rf

• Sextupoles for chromaticity correction

18Gollwitzer -- 8th IDS-NF Meeting

Compressor FMC

April 19, 2012

• Nearly Isochronous lattice

– αp =-0.01– Smaller dispersion– Need more sextupole – 28.5m cells

• RF compression – 2000 turns (~2ms)– ~240kV – Δp/p +/- 1.5%

19Gollwitzer -- 8th IDS-NF Meeting

FMC Ring Parameters

April 19, 2012

Parameter AR CR

Circumference, m 308.23 308.23 

Momentum compaction -0.052 0.001

Slippage factor -0.063 -0.01

RF frequency, MHz 3.87 3.87

RF voltage, kV 10 240

Synchrotron tune 2.110-4 4.210-4

Peak current, A 100 1040

Final r.m.s. bunch length, ns 29.2 3.2

Final r.m.s. energy spread 5.210-4 6.910-3

Threshold impedance, Ohm 20 3 53

R.m.s. emittance, m 5 5

Space charge tuneshift, h/v (Gaussian distribution)

0.02/0.02 0.14/0.16

Betatron tunes, h/v 7.94/6.91 6.76/8.44

Gollwitzer -- 8th IDS-NF Meeting 20

Rings’ Discussion• Where at / What to do

– Basic calculations show beam• Stability• Manageable tune shift

– Injection• Incoming beam line constrained by 8 GeV Hminus

rigidity• Striping

– Rotating foil– Laser

• Absorber for non-proton particles

– Extraction• Kicker parameters

April 19, 2012

21Gollwitzer -- 8th IDS-NF Meeting

Siting?

April 19, 2012

Could share same tunnel?

Gollwitzer -- 8th IDS-NF Meeting 22

Final Focus• Understanding desired proton beam path

in 20T solenoid to target – Will beam path miss jet apparatus– How beam size changes as approach

shielding-solenoid-target• Where can the last quad be placed

• Started interacting with target group about desired beam parameters

April 19, 2012

Gollwitzer -- 8th IDS-NF Meeting 23

Summary• Task Force has shown feasibility that there

is an upgrade path for Project X to provide 4 MW at 8 GeV

• Beam formatting can be accomplished by the addition of Accumulator and Compressor rings– Design/investigation of rings continues

• Interacting with target group in designing final focus beam line.

April 19, 2012