# Presentation: 781528

## Project X: Recycler 8.9 GeV/c Extraction

-  D. Johnson, E. Prebys, M. Martens, J. Johnstone

- Fermilab Accelerator Advisory Committee
- August 8, 2007
- D. Johnson

## Outline

- Accelerator Layout
- Beam Parameters
- Extraction Options
- Conclusions

- Aug 8, 2007                        AAC meeting                           D. Johnson

- 1

## Cartoon of MI/Recycler Extraction (and Injection)

- MI30

- MI10

- MI52

- MI40

- MI60

- Recycler

- Main Injector

**8-GeVline**

**Nova: Booster-Recycler**

**Nova: Recycler-MI**

**P1 line**

**Proposed: Recycler-P1**

**MI abort**

**Recycler abort**

**Abort Bypass**

**NuMI**

- MI62

- MI22

- MI32

**Project X  - Linac**

- R

- R

- R

- Aug 8, 2007                        AAC meeting                           D. Johnson

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## Extraction location – 52

- Main Injector
- MI extracts to Tevatron, Pbar, and Switchyard via P1 beamline
- Extraction channel: kicker/electrostatic septa at Q520 and magnetic Lambertson Q522

- Recycler
- Add kicker and/or septa at 520 with Lambertson at 522 bending down toward the P1 line.
- Connect with P1 line upstream of Q703 [Ref. Beam doc 2678]

- septa

- kicker

- Lambertson’s

- Aug 8, 2007                        AAC meeting                           D. Johnson

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## Extraction location -40

- Both MI and Recycler abort extraction system located at 40
- Share same abort absorber
- Beam bypass built into beam absorber
- EPP 6-7-1 (1994) developed “green field” experimental area downstream of MI-40
- Addition of kicker/dipole in beam line to switch between abort and experimental area
- Beam could be supplied to area from either MI or Recycler
- No effort has gone into further development since 1994

- Aug 8, 2007                        AAC meeting                           D. Johnson

- 4

## Extraction from the Recycler

- Machine/Beam parameters
- Linac operates 5 Hz , 9 mA, and 1ms injection time
- Corresponds to about 5.3E13 protons injected into Recycler with a 700 ns abort gap each Linac cycle
- 3 cycles for MI injection w/ cycle of 1.4 sec 160 kW (8GeV)
- 4 cycles for use (elsewhere) > 200 kW (8GeV)
**Bunch filling determined by digital 325 Mhz chopper in Linac **
**Inject into 53 Mhz buckets using transverse and longitudinal painting to          25 ********-mm-mr and 0.5 eV-sec**
**Required dp/p of 0.5% with chromaticities of -10 to -30 @ full intensity**
- Harmonic number, h = 588  (84x7)
- Circumference  3319.390 meters
- Tunes 25.425 and 24.415 (design)
- Max number of bunches: ~546 (42 buckets  abort gap)
- RF HV 800 kV 1st and 400 kV 2nd harmonic
- Bunch length 10-12 ns

- Aug 8, 2007                        AAC meeting                           D. Johnson

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## Fast Extraction

**Utilize combination of kicker (H) and magnetic Lambertson (V) separated by 90****o**** in phase**
**Extract full turn **
**Requires an abort gap in beam (750ns) – currently done in MI**
**Rise time of 750 ns, flattop time 9.8 ********s**
**Extract 1/6****th**** of full ring (one Booster batch)**
**Requires kickers with 60 ns rise/fall time **
**Similar to current MI injection kicker  (vertical)**
** ****Horizontal kicker being developed for Nova injection**
**Operation at 15 Hz implies 3 “batches” extracted/Linac cycle**
**Bunch-by-bunch extraction**
**Requires 6-8 ns rise/fall time with 10-12ns flattop**
**Requires combination of fast kicker and electrostatic septum**
**For pulsar voltage of 20 kV on each +/-plate requires only about 5m of kicker 25 mm separation at electrostatic septa**
**Power supplies have been developed which have similar parameters (LLNL) – not unthinkable at 8 GeV **

- Aug 8, 2007                        AAC meeting                           D. Johnson

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## Resonant Extraction

**Previous experience:**
**Fermilab Main Ring and Tevatron 1⁄2 Integer Resonant Extraction (400 GeV and 800 GeV program)**
**Fermilab MI 1⁄2 Integer Resonant Extraction (120 GeV)**
**Fermilab has never utilized 1/3 Integer Extraction**
**1/3 Integer resonant extraction utilized by other labs, ANL, BNL, CERN**
**1/3****rd**** Integer resonant extraction from the Debuncher is being investigated (mu2e collaboration meeting, Aug 1, 2007)**
**Fermilab has never implemented resonant extraction at 8 GeV**
**Simulations, utilized for MI resonant extraction at 120 GeV,[Beams-doc-092] have been adapted for 8 GeV MI resonant extraction  [J. Johnstone]**
**1000 particles (all particles accumulated in extracted phase space)**
**3 cases with all particles at dp/p values of -.15%, 0%, or +.15%**
**Circulating beam is a snapshot halfway thru extraction**
**Septum located at -16mm and base tune set to 0.025 from the half-integer**
**Large circulating beam size /aperture ratio problematic**
**Large tune spread due to momentum spread/chromaticity problematic **

- Aug 8, 2007                        AAC meeting                           D. Johnson

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## Resonant Extraction From the Recycler

- Option NOT VERY ATTRACTIVE, if even possible

**MI 120 GeV resonant extraction**

**septum**

**Lambertson**

**dp/p < 0**

**dp/p > 0**

**MI (Recycler) 8 GeV extraction**

**septum**

**For Comparison**

**dp/p = -0.155%**
**             ****0 %**
**           ****+0.155%**

**x =  -10 units**
****** ****= +/- 0.015**

****** ****=  0.025**

**Initial conditions used in**
**simulations: **

****** ****= 25 ********-mm-mr**

**Low dp/p extracted beam **
**overlaps high momentum **
**circulating beam: No GAP**

**dp/p = 0**

**Lambertson**

- Aug 8, 2007                        AAC meeting                           D. Johnson

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**Onset of extraction**

## Conclusions

- Two extraction channels from the Recycler have potential for being developed
- 52 could supply beam to all existing areas
- 40 is a new “green field” area that could be developed
- Fast extraction of beam from single bunches to a full ring appear to be feasible (R&D needed for bunch-by-bunch)
- Resonant Extraction from the Recycler does not appear to be feasible

- Aug 8, 2007                        AAC meeting                           D. Johnson

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