# Presentation: 090487

## LEMC Scenario(More of a Goal)

- BNL MC 2007 workshop

**LEMC Scenario****(More of a Goal)**

- Rolland Johnson, Muons, Inc.

## Muons, Inc. Philosophy

- Nothing designed today will be used exactly as imagined now
- Better ideas always come along
- Muon Colliders need an existence-proof design
- To get support (more attractive is better)
- Innovation is our contribution
- Push ideas, technology
- Source of our income

- Rol -12/03/2007

- BNL MC 2007 workshop

## 14 2008 DOE Ph I Proposals

**	****Working Title**                             **Inst.   PI  subPI**            **DOE topic/office**
- Achromatic low beta for colliders     JLab  Johnson Derbenev          49a HEP
- RF Breakdown Studies                   LBNL  Sah       Li                     50a HEP RF
- GUI for Radiation Simulations         Jlab   Roberts  Degtiarenko       3a BES
- HTS High Field Magnets                  FSU   Kahn     Schwartz          51a HEP HTS
- High Power SRF coupler                 JLab  Johnson Rimmer              3b BES
- Hydrogen Filled RF Cavities            FNAL Johnson Yonehara          50a HEP RF
- Multi-Pixel Photon Counters            FNAL Abrams  Deptuch           52a HEP Det
- Multi-purpose Fiber Optic for HTS    FSU   Johnson Schwartz         51b HEP HTS
- Novel Muon Collection                    FNAL  Johnson Ankenbrandt    49a HEP
- Plasma Lenses                               BNL   Kahn     Hershcovitch     49b HEP
- Pulsed-focusing RLA                       Jlab   Johnson Bogacz             49a HEP
- Rugged Ceramic Window                Jlab   Johnson Rimmer            36a NP
- Ultra-pure Metallic Deposition         FNAL Kuchnir  Wu                   36a NP
- User-Friendly Detector simulations  Uchi  Roberts  Frisch               45b nonprolif
- 			(all are related to Muon Colliders)

- Rol -12/03/2007

- BNL MC 2007 workshop

## Recent Inventions and Developments

- BNL MC 2007 workshop

- Recent Inventions and Developments

**New Ionization Cooling Techniques**
- Emittance exchange with continuous absorber for longitudinal cooling
- Helical Cooling Channel
- Effective 6D cooling (simulations: cooling factor >50,000 in 160 m)
- Momentum-dependent Helical Cooling Channel
- 6D Precooling device
- 6D cooling demonstration experiment (>500% 6 D cooling in 4 m)
- 6D cooling segments between RF sections
- Ionization cooling using a parametric resonance
**Methods to manipulate phase space partitions**
- Reverse emittance exchange using absorbers
- Bunch coalescing (neutrino factory and muon collider share injector)
**Technology for better cooling**
- Pressurized RF cavities
- simultaneous energy absorption and acceleration and
- phase rotation, bunching, cooling to increase initial muon capture
- Higher Gradient in magnetic fields than in vacuum cavities
- High Temperature Superconductor for up to 50 T magnets
- Faster cooling, smaller equilibrium emittance

- See Fernow lattice with magnetic field suppression for vacuum RF

##    Alternative technological paths to a LEMC are emerging

- BNL MC 2007 workshop

-    Alternative technological paths to a LEMC are emerging

- Muon Capture and Precooling in HCC
- 6-d Cooling – (first 6 orders of 6D cooling)
- HCC with imbedded High-Pressure RF (original),
- MANX HCC segments alternating with RF, and/or
- Guggenheim Helix
- Extreme Transverse Cooling – (2 orders)
- Parametric-resonance Ionization Cooling,
- Reverse Emittance Exchange REMEX,
- High-Temperature Superconductor for high B, and
- Ring designs using clever field suppression for RF
- Acceleration in ILC structures
- Dogbone RLA with pulsed quads

## Particle Motion in a Helical Magnet

- BNL MC 2007 workshop

*Particle Motion in a Helical Magnet*

**Blue: Beam envelope**

**Red: Reference orbit**

**Magnet Center**

*Combined function magnet (invisible in this picture)*
- 	Solenoid + Helical dipole + Helical Quadrupole

**Dispersive component makes longer path length for higher momentum particles and shorter path length for lower momentum particles.**

- Opposing radial forces

- Transforming to the frame of the rotating helical dipole leads to a time and z –independent Hamiltonian
*b' added for stability and acceptance*

## Some Important Relationships

- Rol -12/03/2007

- BNL MC 2007 workshop

- Hamiltonian Solution

- Equal cooling decrements

- Longitudinal cooling only

- ~Momentum slip factor

- ~

## HCC as Decay Channel

- BNL MC 2007 workshop

- HCC as Decay Channel

- 40 m evacuated helical magnet pion decay channel followed by a 5 m liquid hydrogen HCC (no RF)

## Adjusting gamma t to get a short muon bunch

- BNL MC 2007 workshop

- abscissa is time (ns)
- ordinate is p (MeV/c)

- usual picture

- gamma t ~ 250 MeV/c

- black are pions
- red are muons

- work in progress by Yoshikawa, Neuffer, and Ankenbrandt

## compressed muon bunch

- BNL MC 2007 workshop

## 5 m Precooler and MANX

- BNL MC 2007 workshop

- New Invention: HCC with fields that decrease with momentum.  Here the beam decelerates in liquid hydrogen (white region) while the fields diminish accordingly.

## Precooler + HCCsWith first engineering constraints

- BNL MC 2007 workshop

*Precooler + HCCs**With first engineering constraints*

*Solenoid + High Pressurized RF*

- Precooler

- Series of HCCs

- The acceptance is sufficiently big.
- Transverse emittance can be
-   smaller than longitudinal emittance.
- Emittance grows in the longitudinal
-   direction.

## Engineering HCC with RF

- BNL MC 2007 workshop

| parameters |  |  | Bz | bd | bq | bs | f | Inner d of coil | Expected
Maximum b | E | RF phase |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| unit | m |   | T | T | T/m | T/m2 | GHz | cm | T | MV/m | degree |
| 1st HCC | 1.6 | 1.0 | -4.3 | 1.0 | -0.2 | 0.5 | 0.4 | 50.0 | 6.0 | 16.4 | 140.0 |
| 2nd HCC | 1.0 | 1.0 | -6.8 | 1.5 | -0.3 | 1.4 | 0.8 | 30.0 | 8.0 | 16.4 | 140.0 |
| 3rd HCC | 0.5 | 1.0 | -13.6 | 3.1 | -0.6 | 3.8 | 1.6 | 15.0 | 17.0 | 16.4 | 140.0 |

- Use a pillbox cavity (but no window this time).
- RF frequency is determined by the size of helical solenoid coil.
- Diameter of 400 MHz cavity = 50 cm
- Diameter of 800 MHz cavity = 25 cm
- Diameter of 1600 MHz cavity = 12.5 cm

- The pressure of gaseous hydrogen is 200 atm at room temp to
-    adjust the RF field gradient to be a practical value.
- The field gradient can be increased if the breakdown would be
-    well suppressed by the high pressurized hydrogen gas.

**Incorporating RF cavities in Helical Cooling Channels**

- Helical solenoid coil

- RF cavity

- RF Window

**GH2**

- RF is completely
- inside the coil.

## Simple pillbox of Al at 400 MHz and LN2 temperature, resistivity 0.4 E-6 Ohm cmHFSS results  

- rel = 1.32

- 154 kW, on one side
- of 1 foil

- 63 kW on inner mantle

- Upeak = 800 kV,  for crossing with
- betaparticle infinity (transit factor = 1)

- Radius = 0.25 m
- Height .= 0.05 m

- 371 kW total/pillbox during passage of trains,
- ~6 kW average

- Q = 26630
- W = 3 Joule/pillbox
- R/Q =(Upeak)2/W = 42.5 Ohm
- circuit convention

- Note that for a given Ez, and scaled
- dimensions R/Q remains unchanged:
- the 1.6 GHz pillbox has the same
- R/Q as the 400 MHz one.

- BNL MC Workshop

- lars-11/25/2007

## MuCool Test Area (MTA)

- BNL MC 2007 workshop

**5T Solenoid**

**Pressure barrier**

**Mark II Test Cell**** **

- _MuCool Test Area (MTA)_

**Wave guide to coax adapter**

## HPRF Test Cell Measurements in MTA

- BNL MC 2007 workshop

- _HPRF Test Cell Measurements in MTA_

**Electrode breakdown region**

-  Paschen curve verified
-  Maximum gradient limited by breakdown of metal.
-  Cu and Be have same breakdown limits (~50 MV/m), Mo(~63MV/m), W(~75MV/m).
-  Results show no B dependence, much different metallic breakdown than for vacuum cavities.
-  **Need beam tests to prove HPRF works.**

- 100 atm

## Parametric-resonance Ionization Cooling 

- BNL MC 2007 workshop

**Parametric-resonance Ionization Cooling **

- Excite 1⁄2 integer parametric resonance (in Linac or ring)
- Like vertical rigid pendulum or 1⁄2-integer extraction
- Elliptical phase space motion becomes hyperbolic
- Use xx’=const to reduce x, increase x’
- Use IC to reduce x’
- Detuning issues being addressed (chromatic and spherical aberrations, space-charge tune spread).  Simulations underway.
- Smaller beams from 6D HCC cooling essential for this to work!

- X’

- X

- X’

- X

## Reverse Emittance Exchange, Coalescing 

- BNL MC 2007 workshop

**Reverse Emittance Exchange, Coalescing **

- p(cooling)=100MeV/c, p(colliding)=2.5 TeV/c => room in Δp/p space
- Shrink the transverse dimensions of a muon beam to increase the luminosity of a muon collider using wedge absorbers
- Allow bunch length to increase to size of low beta
- Low energy space charge, beam loading, wake fields problems avoided
- 20 GeV Bunch coalescing in a ring Neutrino factory and muon collider now have a common path

- p

- t

- Concept of Reverse Emittance Exch.

- 1.3 GHz Bunch Coalescing at 20 GeV

- RF

- Drift

- Cooled at 100 MeV/c

- RF at 20 GeV

- Coalesced in 20 GeV ring

## Bhat et al. Coalescing 

- BNL MC 2007 workshop

- Bhat et al. Coalescing

- 20 GeV muons in a 100 m diameter ring

##          700 m muon Production and Cooling          (showing approximate lengths of sections)

- BNL MC 2007 workshop

-          700 m muon Production and Cooling          (showing approximate lengths of sections)

- 8 GeV Proton storage ring, loaded by Linac
- 2 T average implies radius=8000/30x20~14m
- Pi/mu Production Target, Capture, Precool sections
- 100 m		 (with HP RF, maybe phase rotation)
- 6D HCC cooling, ending with 50 T magnets
- 200 m		 (HP GH2 RF or LH2 HCC and SCRF)
- Parametric-resonance Ionization Cooling
- 100 m
- Reverse Emittance Exchange (1st stage)
- 100 m
- Acceleration to 2.5 GeV
- 100 m at 25 MeV/c accelerating gradient
- Reverse Emittance Exchange (2nd stage)
- 100 m
- Inject into Proton Driver Linac
- Total effect:
- Initial 40,000 mm-mr reduced to 2 mm-mr in each transverse plane
- Initial ±25% Δp/p reduced to 2% , then increased
-  exchange for transverse reduction and  coalescing
- about 1/3 of muons lost to decay during this 700 m cooling sequence
- Then recirculate to 23 GeV, inject into racetrack NF storage ring

- Detailed theory in place, simulations underway.

## Fernow-Neuffer Plot

- BNL MC 2007 workshop

- Initial point

- PIC

- REMEX +coalescing

- HCC

- Cooling required for 5 TeV COM, 1035 Luminosity Collider.                    Need to also look at losses from muon decay to get power on target.  Higher magnetic fields from HTS can get required HCC performance.

## new ideas under development: 

- BNL MC 2007 workshop

- new ideas under development:

- H2-Pressurized RF Cavities
- Continuous Absorber for Emittance Exchange
- Helical Cooling Channel
- Parametric-resonance Ionization Cooling
- Reverse Emittance Exchange
- RF capture, phase rotation, cooling in HP RF Cavities
- Bunch coalescing
- Very High Field Solenoidal magnets for better cooling
- Z-dependent HCC
- MANX 6d Cooling Demo
- Besides these SBIR-STTR supported projects, note that Bob Palmer, Rick Fernow, and Steve Kahn have another path to low emittance.

## Muon Collider use of 8 GeV SC Linac

- BNL MC 2007 workshop

- Muon Collider use of 8 GeV SC Linac

- Instead of a 23 GeV neutrino decay racetrack, we need a 23 GeV Coalescing Ring.   Coalescing done in 50 turns (~1.5% of muons lost by decay). 10 batches of 10x1.6 1010 muons/bunch become 10 bunches of 1.6x1011/bunch. Plus and minus muons are coalesced simultaneously. Then 10 bunches of each sign get injected into the RLA (Recirculating Linear Accelerator).

- μ+ to RLA

- μ- to RLA

**23 GeV Coalescing Ring**

## 1.5 TeV COM Example

- BNL MC 2007 workshop

## 5 TeV ~ SSC energy reach

- BNL MC 2007 workshop

- ~5 X 2.5 km footprint
- Affordable LC length (half of baseline 500 GeV ILC), includes ILC people, ideas
- More efficient use of RF: recirculation and both signs
- High L from small emittance!
- 1/10 fewer muons than originally imagined:                  a) easier p driver, targetry       b) less detector background    c) less site boundary radiation

- Beams from 23 GeV Coalescing Ring

## Muon Collider Emittances and Luminosities

- BNL MC 2007 workshop

**Muon Collider Emittances and Luminosities**

- After:
- Precooling
- Basic HCC 6D
- Parametric-resonance IC
- Reverse Emittance Exchange

-    εN tr		 εN long.
- 20,000	μm	10,000 μm
-     200 μm 	     100 μm
- 25  μm 	     100 μm
-   2	μm 	         2 cm

- At 2.5 TeV on 2.5 TeV

- 20 Hz Operation:

- Many things get easier as muon lifetime increases!

## Parameter Spreadsheet

- BNL MC 2007 workshop

- On workshop web page
- A working document to connect pieces
- Consistent beginning to end connections
- Example: change collider E, see P on target change
- Will become basis for design report
- Includes play pages for “what-if” scenarios
- See Mary Anne or me with suggestions for additions and improvements e.g. Site boundary radiation levels,  wall-plug power, linac wakefield and beam loading parameters, cost, etc.

## Important Recent Developments 

- BNL MC 2007 workshop

- Important Recent Developments

-  Anticipated LHC discoveries are inspiring muon cooling and collider research
-  Accelerator Physics Center formed at Fermilab, MCTF
-  New SBIR projects
-  RF cavities pressurized with dense hydrogen under development
-  Support surface gradients up to 70 MV/m even in large magnetic fields
-  p beam line available soon for next tests
-  Helical Solenoid magnet invention will simplify HCC designs
-  Prototype section SBIR funded for design, construction, and testing
-  New HTS materials look promising for very large fields
-  MANX is close to being a supported 6D demonstration experiment
-  Collaboration being formed, experimental proposal drafted
-  Looking for collaborators!

- Rol -12/03/2007

- BNL MC 2007 workshop

## Updated Letter of Intent to Propose MANX, A 6D MUON BEAM COOLING EXPERIMENT 

- BNL MC 2007 workshop

**Updated Letter of Intent to Propose ****MANX, A 6D MUON BEAM COOLING EXPERIMENT**** **

- Robert Abrams1, Mohammad Alsharo’a1, Charles Ankenbrandt2, Emanuela Barzi2,
- Kevin Beard3, Alex Bogacz3, Daniel Broemmelsiek2, Alan Bross2, Yu-Chiu Chao3,
- Mary Anne Cummings1, Yaroslav Derbenev3, Henry Frisch4, Stephen Geer2,
- Ivan Gonin2, Gail Hanson5, Martin Hu2, Andreas Jansson2, Rolland Johnson1,
- Stephen Kahn1, Daniel Kaplan6, Vladimir Kashikhin2, Sergey Korenev1,
- Moyses Kuchnir1, Mike Lamm2, Valeri Lebedev2, David Neuffer2, David Newsham1, Milorad Popovic2, Robert Rimmer3, Thomas Roberts1, Richard Sah1, Vladimir Shiltsev2, Linda Spentzouris6, Alvin Tollestrup2, Daniele Turrioni2, Victor Yarba2,
- Katsuya Yonehara2, Cary Yoshikawa2, Alexander Zlobin2
- 1*Muons, Inc.*
- 2*Fermi National Accelerator Laboratory*
- 3*Thomas Jefferson National Accelerator Facility*
- 4*University of Chicago*
- 5*University of California at Riverside*
- 6*Illinois Institute of Technology*
**http://www.muonsinc.com/tiki-download_file.php?fileId=230**

-  Contact, _[rol@muonsinc.com](mailto:rol@muonsinc.com)_, (757) 870-6943
-  Contact, _[jansson@fnal.gov](mailto:jansson@fnal.gov)_, (630) 840-2824

## 6DMANX demonstration experimentMuon Collider And Neutrino Factory eXperiment  

- BNL MC 2007 workshop

- 6DMANX demonstration experiment_M_uon Collider _A_nd _N_eutrino Factory e_X_periment

- To Demonstrate
- Longitudinal cooling
- 6D cooling in cont. absorber
- Prototype precooler
- Helical Cooling Channel
- Alternate to continuous RF
- 5.5^8 ~ 10^6 6D emittance reduction with 8 HCC sections of absorber alternating with (SC?)RF sections.
- New technology

## Uses for a HCC

- BNL MC 2007 workshop

- Decay channel
- Precooler
- MANX 6D cooling demo
- Stopping muon beam cooler
- can add RF for even better cooling (path to a MC)
- Fast 6D Emittance reduction
- new approach to neutrino factory (path to a MC)
- Preliminary to extreme cooling (needed for a MC)
- Parametric Ionization Cooling
- Reverse Emittance Exchange and muon bunch coalescing

## Matching + Helical Cooling Magnets

- BNL MC 2007 workshop

-  Helix period = 1.2 m
-  Number of coils per period = 20
-  Coil length = 0.05 m
-  Gap between coils = 0.01 m
-  Current = 430.0 A/mm2

- Increase gap between coils from 10 to 40 mm

- HCC

- Downstream
- Matching

- Upstream
- Matching

**Design of HCC Magnet**

-  Gap between coils = 0.04 m
-  Current = 1075.0 A/mm2

## Overview of MANX channel

- BNL MC 2007 workshop

- Use Liquid He absorber
- No RF cavity
- Length of cooling channel: 3.2 m
- Length of matching section: 2.4 m
- Helical pitch : 1.0
- Helical orbit radius: 25 cm
- Helical period: 1.6 m
- Transverse cooling: ~1.3
- Longitudinal cooling: ~1.3
- 6D cooling: ~2

**6DMANX**

- Most Simulations use G4Beamline (Muons, Inc.) and/or ICOOL (BNL)

- G4BL Simulation