# Presentation: 037901

## -Factory Front EndPhase Rotation Simulations

- David Neuffer
**Fermilab**
**Muons, Inc.**

## 0utline

**Neutrino Factory Front End Optimization**
**Improve neutrino factory scenario**
**For International Scoping study **
**“****High-frequency” Buncher and ******** Rotation**
**Study 2A**** scenario, Obtains  ~0.2 ********/p**
**Gas filled cavities **
**Higher gradients? ****In magnetic fields?**
**Cooling in buncher and rotator/shorter cheaper ? System**

## Neutrino Factory - Study 2A

- Proton driver
- Produces proton bunches
- 8 GeV  1015 p/s
- Target and drift
-   (> 0.2 /p)
**Buncher, bunch rotation, cool**
- Accelerate  to 20 GeV
- Linac, RLA and FFAGs
- Store at 20 GeV (0.4ms)
-  e ++ e*
- Long baseline  Detector
- >1020 /year

## Study2AP June 2004 scenario

**Target**- Hg-jet within 20T solenoid
- Drift –110.7m – within 1.75T solenoid
**Bunch** -51m
- V(1/) =0.0079
- 12 rf freq., **110MV**
- 330 MHz  230MHz
******-E Rotate** – **54m –**** ****(416MV total)**
**15 rf freq. 230******** 202 MHz**
- P1=280 , P2=154 ******N****V**** = ****18.032**
**Match and cool** (80m)
- 0.75 m cells, 0.02m LiH
- “Realistic” fields, components

## Simplest Modification from Study 2A

**Cool here**

**Add gas** + higher gradient to obtain **cooling within rotator**
- ~300MeV energy loss in cooling region
- Rotator is 54m;
- Need ~4.5MeV/m H2 Energy
- 133atm, 295oK gas
- ~250 MeV energy loss
- Alternating Solenoid lattice in rotator
- 20MV/m rf
- Lattice changes

## “Final” configuration

- Drift, buncher as before:
- 300 230MHz rf
- 51m, V =3 z/z0 +9(z/z0)2
- “match” fron 2 T to 2.75T alternating solenoid at end of buncher
- Rotator lattice
- 0.75m cells, 0.5m rf/cell
- 133A H2, 3.4 MeV/cell
- V=20MV/m, φ=20°
- 54m
- Post Rotator Cooling lattice
- V=16MV/m
- 133A H2

- B(z)

## ICOOL results- gas cavities

- End of Rotator

**~0.20 ****μ/p** within reference acceptance at end of φ-E Rotator
**~0.10 μ/p** within restricted acceptance (ε⊥<0.015m)
- Rms emittance cooled from ε⊥ = 0.019 to                ε⊥ = ~0.009
- Longitudinal rms emittance ≅0.075
- Continuing Study 2A cooling does not greatly improve acceptance

## Cooling simulation results

## Modify initial solution

- Transverse emittance

- Acceptance

- Change pressure to **150Atm**
- Rf voltage to **24 MV/m**
- Transverse rms emittance cools 0.019 to ~0.008m
- Acceptance **~0.22********/p** at        εT < 0.03m
- ~0.12/p at εT < 0.015m

## Same geometry – Be Windows

- Replace 150 A gas with 0.65cm thick Be windows on cavities
- Similar dynamics as H2 but
**Much worse** Study 2A performance (?)
- Transverse emittance cooling : 0.019→ 0.0115
- Muons within Study 2A acceptance:
**0.134 ****μ/p** (εt < 0.03)
- 0.056 μ/p (εt < 0.015)
- Needs reoptimization?

## Try LiH Windows

- Replace 150 A gas with 1.2cm thick LiH windows on cavities
- Similar dynamics as Be but
**Slightly better** than Be performance (?)
- Transverse emittance cooling : 0.019→ 0.0102
- Muons within Study 2A acceptance:
**0.160 ****μ/p** (εt < 0.03)
- 0.075μ/p (εt < 0.015)
- Needs reoptimization?

## Cost estimates:

- Costs of a neutrino factory (MuCOOL-322, Palmer and Zisman):

**Study 2 **

**Study 2B**** **

- Combining cooling and phase rotation may reduce cost by ~ 100M$

## Component cost basis

- M$/GeV?

## Cost impact of Gas cavities

- Removes 80m cooling section  **(-185 M$)**
- Increase Vrf' from 12.5 to 20 or 24  MV/m
- Power supply cost  V'2 (?)
- 44 M$  107M$ or 155M$
- Magnets: 2T  2.5T Alternating Solenoids
- 23 M$  26.2 M$
- Costs due to vacuum  gas-filled cavities  (??)
- Total change:
**Cost decreases by 110 M$ to 62 M$**  (???)

## Summary

- High-frequency Buncher and E Rotator (ν-Factory)
**Variations (****Poklonskiy may help****),**
**Shorter systems ??**
**Other frequencies ?**
**Gas-filled rf cavities**
**Higher gradient??**
**Optimize V’**** **
**Cool in buncher rotator**
**To do:****	**
- Optimizations, Best Scenario, cost/performance ...

## Motivation ...

## Front end with high-pressure cavities

- See K. Paul
- More for μ-Collider
- Keep beam within 1 or fewer bunches
- Cavities start near target
- (More radiation)
- Capture / phase rotate within a few meters
- Gas cavities enable cooling