# Presentation: 801460

##  AGS as a Proton Driver for a Neutrino Factory

-                          W. T. Weng
-          Brookhaven National Laboratory
-          NuFact & Mu-Coll. Collaboration
-              UCLA, CA, Jan/29–Feb/1, 2007

## Outline

-  Evaluation of parameter dependence
-  Possible design parameter phase space
-  Improvements on the AGS, and its
-        difficulties
-  Summary and Conclusions

## Considerations of parameters 

- we consider the effects of
- Energy
- Repetition Rate
- Intensity
- Bunch Length
- Number of bunches
- Of the Proton Driver

## Proton per pulse required for 4 MW

|  | 10 Hz | 25 Hz | 50 Hz |
| --- | --- | --- | --- |
| 10 GeV | 250 × 1012 | 100 × 1012 | 50 × 1012 |
| 20 GeV | 125 × 1012 | 50 × 1012 | 25 × 1012 |

## Process mesons through Cooling

-    Analysis II
-     Post Cooling
- Count mesons within
- acceptance of 30π mm

## Post-cooling  30π Acceptance

## Preferred Beam Energy

- For Negatives the peak occurs for
-       6 Gev < Proton KE < 11 GeV
- For Positives the peak occurs for
-       9 Gev < Proton KE < 19 GeV
**Consensus: 10 GeV is a good place to start**

## Target/Beam Baseline used for comparison

## Summary of Target Performance

| 
  1 MW/50 Hz
 12.0 e+12 ppp
     YES | 
  4 MW/50 Hz
 48.0 e+12 ppp
   NO |
| --- | --- |
| 
  1 MW/200 Hz
 3.0 e+12 ppp
   YES
 | 
  4 MW/200 Hz
 12.0 e+12 ppp
  MAYBE |

## Design Parameter Phase Space

- 8.0 GeV < Energy < 20.0 GeV
- Rep Rate ~ 50(25) Hz
- Intensity 50*10**(12) ppp, at 10(20) GeV
-       ( very difficulty with solid target )
- 4.   Bunch Length < 3 ns, for longitudinal
-                                           acceptance
- 5.   Number of bunches 3 ~ 5

## 2 MW AGS Proton Driver

- AGS proton driver layout for alternate injector linac design.

## Methods of generating Short Bunch

- Short bunch can be generated by a compressing RF system
- It can also be generated by bunch rotation
-    in the ring, or in the external beam line
-    ( both of them need extreme high rf voltage)
- We try to do it by getting to the transition
-    energy at extraction( low voltage is sufficient )

## AGS parameters at Transition

## Beam Parameters around Transition

- Typical variation of , R, and E as the beam energy increases.

## Longitudinal Space Charge Effect

- sc parameter,
- scaling relation,
- (E. Courant, 1968)

- Longitudinal phase space of the proton beam before, at, and after crossing the transition energy in the AGS obtained with the computer code TIBETAN.

- Expected fractional beam loss upon transition crossing as a function of the initial (95%) longitudinal beam area obtained with the computer code TIBETAN.

## AGS as a Proton Driver

## Difficulties with this Scenario

- High current and single bunch intensity all exceed space charge limits
- Need rebunching for 3 ~ 5 bunches, unless
-     allowing 6 batch extraction over 10 ~ 20 usec.
- Limitations of RF and PS systems
- Need better matching lattice at transition
- Possible beam losses and activation
- It seems 2 MW is the upper limit at the AGS

## Decisions needed on Proton Driver

- Performance requirements
- Viability of existing driver proposals
- Whether to focus on a new design
-       with an integrated design team
- 4.   Cost to the total facility

## Summary and Conclusions

- Performance parameters of a PD for NuFact has been reviewed
- Ways to convert the AGS are described
- It is difficulty to meet all requirements
- Site-independent new design has to be initiated, if other existing designs also can not meet the requirements.