# Presentation: 129187

## Theory and SimulationJonathan Wurtele, UCB/LBNLPresentation to MUTAGJune 16, 2000BNL

- Overview
- The challenges of muon capture, bunching        and cooling
- Future Plans

## Theory and Simulation Overview

- Proton Driver (site-specific)
- Target (specialized: MARS (Mokhov); FLUKA)
- Frontend
- Acceleration
- Storage

- Moun Collaboration

## Front End: Target to start of acceleration

- Moun Collaboration

## Progress since last MUTAG meeting

- Systematic simulations--single code (ICOOL, DPGEANT, PATH) target to end of cooling (and up to ~1GeV)
- Implementation of engineering constraints on rf gradients, cavity windows, aluminum windows for LH absorber, peak magnetic field on conductors,...
- Development of theoretical models for particle transport and cooling in solenoidal channels--greatly increased understanding
- Implementation of single code for comparison for post-processing simulation results

- Moun Collaboration

## Progress (II)_x0008__x0008_

- Coordination--
- LBL 1 month workshop
- Simulation working group (2 from LBL, FNAL, BNL, CERN);
- weekly international conference calls
- Development of different frontend concepts--and means to evaluate them

- Moun Collaboration

## Frontend Design Effort: Status

- Rules:
- Simulate with engineering constraints: B, J, absorber windows, rf windows, ...
- Front end design should be full simulation--target to end of cooling
- Common figure of merit (muons/proton in acceptance of downstream system)
- Accomplishments:
- Integrated simulations for a variety of frontend designs (Monroe, Palmer talks)
- Advances in theoretical understanding (Kim Talk)
- Code development and benchmarking
- Much stronger national and international collaboration

- Moun Collaboration

## SLIDES FROM OTHER PRESENTATIONS--this is a place holder for slides prepared primarily by Gregg on physics of cooling and simulation results

- Moun Collaboration

## Feasibility Study I Results

- Moun Collaboration

## Enhancing Frontend Performance Beyond Feasibility Study 1

- Optimize system, especially matching sections
- Early Phase Rotation
- Compensation of nonlinearity in longitudinal kinematics
- Longer Drift
- Improved induction linac waveform
- Increase bunching efficiency
- Improve cooling channel designs

- Moun Collaboration

## Tools: ICOOL (R. Fernow)

-    Main Features
- 3D tracking code with interactions in matter
- Since last MUTAG meeting:  v1.90 --------> v2.06
- Agrees well with DPGeant
-     Used for Frontend simulations:
- Feasibility I FOFO channel (Kim)
- Feasibility II SuperFOFO channel (Palmer)
- Recent developments
-      New induction linac models
-      Improved spin tracking and new spin depolarization model
-      Hemispherical absorber end region

- Moun Collaboration

## Tools: DPGeant  (based on Geant3, a general HEP simulation tool)

-      Main Features:
-   3D tracking code
-   includes interactions in matter
-   core code library stable
-       Applications to Feasibility Study I (and beyond):
-      single flip channel
-      induction linac
-      Starting to think about transition to Geant4:
-      C++, double precision
-      better visualization
-      more complete set of EM and hadronic physics

- Moun Collaboration

## Limiting factors on performance

- Magnets--limit beta-functions
- RF gradient limits cooling rate (prefer high frequency)
- Aperture limits from scraping at entrance to RF cavities (prefer low frequency)

- Moun Collaboration

## Emittance Exchange

- HARD
- Needs better theoretical capabilities
- Better ways to visualize results and understand why things may not work
- There are lots of ideas, not enough time to try them
- Workshop in September.

- Moun Collaboration

## Theory Plans

- Beam Dynamics
- 4D axicentered DONE
- 6D
- Errors
- Nonlinearities
- Correlations
- Violation of paraxial approximation
- Develop fast design tool using standard ICOOL input specifications
- Instabilities

- Moun Collaboration

## Code Development Plans

- Improve diagnostics and visualization
- Implement optimization and parallelization
- Common input specifications (minimize ‘tweaking’ to compare results)
- Computational issues (runtime, statistics,..)
- New physics (polarization, induction linac model,

- Moun Collaboration

## Experimental Support 

- Specification of required component performance
- Development of instrumentation and diagnostics
- Precision of measurements

- Moun Collaboration

## Macroscopic Studies Plans

- Continue looking at both low complexity and high performance frontend concepts
- Target optimization (Carbon/Mercury,horns)
- Simplified frontend designs-- if polarization is not required.
- eliminate rf near target, replace cooling with drift
- bunch and phase rotate at the same time
- Improve frontend performance:
- Longer drift region
- Initial phase rotation
- Emittance exchange
- Gain understanding of components and how to effieciently match between them
- Study error sensitivities of a particular design
- Optimize wherever possible
- Accelerate into the recirculator
- Continue to collaborate effectively and coordinate with CERN group

- Moun Collaboration

## The challenge

- Maximize # of muons/p-GeV
- Total production of useful pions is roughly . pion/proton-GeV
- Choice of energy influences yield and phase space density.
**+, **-  phase spaces not the same at at 2GeV
- Number of pions in 6D phase space acceptance
- Phase rotation fixes a significant fraction of the problem
- Cooling must handle the rest.

- Moun Collaboration

## Significant progress has been made:

- Benchmarked DPGEANT, ICOOL and PATH
- Theoretical understanding of transverse cooling dynamics
- Improved ICOOL
- Significant engineering concerns included in the simulations
- Started integrated front end simulations
- Learned to work together in a more coherent way (weekly phone calls, extended visits)
- Established working interactions with CERN group

- Moun Collaboration