# Presentation: 168545

## BNL 

** ****BNL, 11-12 June 2006**

- Extinction requirement relaxation (Kevin O’Sullivan)
- Stopping Target Geometry (Cenap Ozben, David Morse)

- _Yannis Semertzidis_
- _BNL__ _

- _Less Pions (Extinction)__More Muons _

## Winning Strategy: hit the ground running...

- Use AGS to provide high proton Intensity with correct timing (relax extinction and high intensity requirements)
- Use FFAG (YK, et al)
- Re-evaluate B-field solenoid requirements (spec them based on physics requirements)

## Winning Strategy: hit the ground running...

- Use *current* AGS capabilities (no upgrades) to provide high proton Intensity with correct timing (relax extinction and high intensity requirements, i.e. task is mostly finished!).

## Winning Strategy: hit the ground running...

- Use FFAG (YK, et al), to get rid of the pions and greatly improve the muon intensity at the correct momentum by phase rotation.
- This also relaxes the solenoid field requirements.
- Re-evaluate B-field solenoid requirements (relax them based on physics)

## Pion Momentum

_**Pion Momentum**_

## Winning Strategy: hit the ground running...

- Overall:  work for a year to produce a proposal.  It may be possible to reduce the cost to $30M for the whole experimental apparatus.

## Extinction

- Primary particles are generated in the target: Sharp source
- Muons are produced from pions: Diffused source
- Different pitch angles and momentum distribution (Phase Space)

## Target in the PS

## Production Target

_**Production Target**_

- Pion source

- Muon source

- Pion helix in B-field

- Muon helix in B-field

## Negative muon y-z distribution

## Muon Y, X distribution at entrance of T.S. (Tumakov’s muons)

_**Muon Y, X distribution at entrance of T.S. **__**(Tumakov’s muons)**_

**X [cm]**

**Y [cm]**

## Pion Y, X distribution at entrance of T.S. (Tumakov’s pions)

_**Pion Y, X distribution at entrance of T.S. **__**(Tumakov’s pions)**_

**X [cm]**

**Y [cm]**

## What is the minimum distance (Rm) of the circle from center?

_**What is the minimum distance (Rm) of the circle from center?**_

**Rm**

## Minimum distance of pion and muon circles from center

_**Minimum distance of pion and muon circles from center**_

**Rm[cm]**

**Pions**

**Muons**

## Minimum distance of pion and muon circles from center

_**Minimum distance of pion and muon circles from center**_

**Rm [cm]**

**Pions**

**Muons**

## Pion minimum distance from center in the Y, X plane

**X [cm]**

**Y [cm]**

- The target is 20cm long and slanted by ~10o, i.e. dx~3cm!

## Muon minimum distance from center in the Y, X plane

**X [cm]**

**Y [cm]**

## Pitch angle for pions and muons

**Pions**
**@ TS**

**Muons**
**@ DS**

**Muons**
**@ TS**

## Pitch angle vs Rm

**Rm [cm]**

**Pions**

**Muons**

## Muon Y, X distribution at the entrance of D.S.

**X [cm]**

**Y [cm]**

**Negative muon losses due to vertical drift. We will study different ways of losing the positive charges (helix in opposite way) with less drift and different collimator geometries.**

## Simulated Trajectories in PS & TS

## Summary (Extinction)

- The pion source is sharp, as opposed to the muon source
- Take advantage of the different phase space of muons and pions, electrons, anti-protons, etc
- “The Plug” promises to reduce the extinction requirements by at least ~102
- _We further need to_
- Optimize the number and geometry of the Plugs
- Study different collimator geometries
- Estimate the plug efficiency

## Visited BNL for three months, until end of May

**Plus David Morse, Summer student**

## Present Target Geometry17 circular foils, 0.2mm thick each

**80cm**

## Muon Stopping Target

- _Muon Stopping Target_

- Increase muon stopping power
- Minimize energy loss for 105MeV electrons and better the collection efficiency

## Considered Various Geometries:

**Original (default) geometry**** of circular foils**

## Non-stop muons: Circular foils

**Muon energy loss [MeV]**

**Muon energy ****before**** and ****after**** the target [MeV]**

## Muon hits : Circular foils

**Muon energy loss [MeV]**

## Stopped muons: Circular foils

**Muon energy loss [MeV]**

**Muon energy ****before**** the target [MeV]**

- muons

- electrons

## Stopped muons: Single cone geometry

**Muon energy loss [MeV]**

**Muon energy ****before**** the target [MeV]**

- 11.5o

## Stopped muons: Multi cone geometry

**Muon energy loss [MeV]**

**Muon energy ****before**** the target [MeV]**

- 40o

## Stopped muons: Multi cone geometry

**Muon energy loss [MeV]**

**Muon energy ****before**** the target [MeV]**

- 80o

## Stopped muons: Multi cone geometry

**Muon energy loss [MeV]**

**Muon energy ****before**** the target [MeV]**

- 40o

## Stopping efficiency for 10,000 muons  (Tumakov’s) for same volume target

| Geometry | Stopped muons | Hit but not stopped |
| --- | --- | --- |
| Circular foils | 2262 | 5026 |
| Single cone | 2705 | 3750 |
| Multiple cones (40o-80o)
60o | 2700-3000

2850 | 4600-4300

4480 |

## Spectrometer Performance Calculations

- _Spectrometer Performance Calculations_

- FWHM ~900 keV

****

- 10

- 1.0

- 0.1

- 0.01

-           103           104            105          106

**Aiming for ~200 KeV/c resolution**

## How do 105 MeV electrons fair?

- Circular foilsFWHM: 0.79MeV

## Signal and DIO from the proposal

**0.8MeV**

## How do 105 MeV electrons fair?

- Single coneFWHM: 0.85MeV

## How do 105 MeV electrons fair?

**How do 105 MeV electrons fair?**

- Multi cone bestFWHM: 0.61MeV

- 60o

## 70o

- 70o

- 50o

- 40o

- 80o

## Summary

- GEANT3 installed on BNL computers with both Rashid’s and Vladimir’s codes.
- Have studied a few geometries including the current circular foils.
- Preliminary results: multi-cones with 60o-70o is best: 25% more muons stopped, with less energy loss for 105MeV electrons and better collect. effic.
-  _We further need to_
- Finish the study
- Study new geometries, to take advantage of the e- pitch
- Include target supports for background estimation