Design of a demonstration of Magnetic
Insulation and study of
its application to Ionization Cooling
for a Muon Collider
Project 38b-911255
John Keane
Particle Beam Lasers ,INC
Team J. Kolonka, R. Palmer, H.Kirk, R. Wegglel,
R. Scanlan, D. Clines, R Gupta, A.Garren
Special Thanks to Ditktys Stratakis
INITIAL THOUGHTS ON “E” FIELD
COUPLING TO AN 800 MHZ. CAVITY
USING MICROWAVE STUDIO
SOFTWARE
What an RF Engineer Wants to Talk
About
Problem
• There are two significant technical challenges in the
development of the required intense muon beams.
• The first is the production and collection of the
muons
• The second is the reduction of the phase space
(cooling) of the muon beam in order to obtain the
required beam properties. Such cooling involves the
reduction of the beam extent in 6-D phase space
Ionization Cooling Fast Enough
• The magnitude of 3-dimensional momentum vectors of
the muon particles are reduced via energy loss in an
ionization media, followed by the subsequent
restoration of only the longitudinal momentum
component with rf power BUT
• Lattices require that rf used for reacceleration should
operate in strong axial magnetic field but rf cavities do
not work well in these fields due to multipactoring.
• This SBIR intends to design an experiment to test the
idea of magnetic insulation and to study its application
to the required lattices the required lattices
Final transverse cooling in high field
solenoids
• It is the design and optimization of Ionization Cooling
at the last stage that our study would be devoted to.
• Anticipated low longitudinal emittance allows us to do
the final cooling in a channel without dispersion or
wedges; a channel that cools only in the transverse
direction allowing the longitudinal emmitance to rise.
• Final transverse emittance requires stronger focusing
than practical with a 6-D cooling lattice.
• HTS can reach fields of 50 T
• Rise in longitudinal emittance , resulting from cooling
at low momentum , can be tolerated
Technical Objectives For the design of
a demonstration of magnetic
insulation
• 1. Design a combination of coils and cavity geometries
to give magnetic insulation on the rf cavity.
• 2. Study and compare the technical requirements for
pulsed copper and HTS coils.
• 3.Determine forces between the coils and determine
the requirements to restrain them.
• 4.Design the rf cavity and coupling to an rf waveguide.
• 5.Make engineering drawings of the experiment.
• 6.Build and test in liquid nitrogen a copper pulsed
solinoid.
Technical Objectives: For the design of
magnetically insulated cavities for a
muon cooling
• 1.Optimize the magnetically insulated rf reacceleration
systems for the use in 6D cooling lattices, to maximize
their acceleration gradients relative to the maximum
surface gradients which will limit the cavity
performance.
• 2. Design LTS, HTS, or Nb3Sn coils to provide magnetic
insulation of the cavities.
• 3. Simulate the 6-D cooling performances, and
optimize that performance by adjusting the dimensions
and magnetic field strengths.
Initial goals for coupling to 805 Mhz.
Cavity
• We are looking for gradients of 50MV/M
• From superfish using our most recent design
Emax /E0 =4.1164
50/4.1164=12.15MV/m
Power= 32.6979 KW for 1MV/m
• Power needed is ((12.15)^)(32.7)= 4.8 MWatts
at room temperature
• This may go down if we use half cell
Half Cell Model
• This is basic model
• This is for normal conductors
• The cavity aperature drives into a ¾
wavelength coax lie
• Variable coax length
• Variable probe length
• Use Eigenmode JDM solver
• Adjust cavity blends for frequency
• Cavity is made of lossy metal
• Coax added
• Use the Q measurements to identify the
rightmode
• Boolien Devil
He strikes again but this time worse
• Flange added.
• When in Frequency solver eliminated lot of
clutter
• Add Waveguide: Booline Again
– Adjustable aperture at boundary.
• Voltage Max away from aperture
Over coupled
• Voltage min. 337-222=115 (WL=93mm air)
• 222-115 = 107mm near aperture
Conclusions
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New computer at BNL with more RAM
Remote hookup so can work from home
Progress on using Microwave Studio
Action plan for coupling to cavity
Introduction to the “Guys and gals
Good memories of time spent with Kurt
Owen, Phil Livdahl, and Don Younge