Transcript Proton Driver

Muons, Inc.
Dielectric-Filled
RF Cavities
Milorad Popovic
FNAL
07/07/2009
MuCool RF Workshop-Fermilab
1
Muons, Inc.
A Tale of Two Cavities
Best of Times-Worst of Times
For HCC
Vacuum Cavity
Cu/Steel
ceramics
Vacuum/H/He
07/07/2008
MuCool RF Workshop-Fermilab
2
Muons, Inc.
Motivation
To fit pressurized cavities in HCC, size of cavity has to be reduced
800 MHz (from Katsuya)
Maximum RF cavity radius = 0.08 m, (pillbox cavity 0.143)
Radius of effective electric field (95 % from peak) = 0.03 m
400 MHz:
Maximum RF radius = 0.16 m (pillbox cavity 0.286)
Radius of effective electric field = 0.06 m
Optimum electric field gradient = 16 MV/m
For Pill Box Cavity, resonant frequency is
2.405c

R  r r
07/07/2008
MuCool RF Workshop-Fermilab
3
Muons, Inc.
• HCC Canal has High Magnetic Fields
• No Magnetic Materials
• Acceleration should be Continues
Dielectric Loaded RF Cavities
Cu/Steel
ceramics
Vaccum/H/He
07/07/2008
MuCool RF Workshop-Fermilab
4
Muons, Inc.
HCC Concept
Central Orbit and Beam Envelope
Set of Coils
Basic Building Block can be Cavity + Coil
07/07/2008
MuCool RF Workshop-Fermilab
5
Muons, Inc.
Cryostat
Vessel
MANX + RF ?
Detecto
rs
Cavity + Coil
MICE will have
~?MV @200MHz
Feedthroug
hs
07/07/2008
Power in
Signals
out
MuCool RF Workshop-Fermilab
6
Muons, Inc.
• Ceramics can play additional role, making volume
of Hydrogen smaller and making cavity stronger so
the walls do not have to be as thick as without
ceramics.
• RF power can be fed using loop between two
rings.
• Cavities can be put next each other so the side
wall can be made thin
We should do experiments in the MTA
201MHz (with solenoid?)
805MHz with solenoid!
07/07/2008
MuCool RF Workshop-Fermilab
7
Muons, Inc.
~400MHz-16MV/m, Q, Power
DielCav 400MHz, epsD=9.58 0.0 muD=1 F = 471.82774 MHz
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
-6
-4
-2
0
2
4
C:\Documents and Settings\popovic\Desktop\HCCav\FishTestDiel\SBRCAV.AM 2-21-2009
Power dissipation = 3240.4953 kW
Q = 10438.9 Re_eps=9.5, Im_eps=0.00029
6
6:18:12
Power dissipation = 2252.4457 kW
Q = 15018.0 Re_eps=9.5, Im_eps=0.0
Lossless Dielectric
07/07/2009
MuCool RF Workshop-Fermilab
8
PAC09 Paper
07/07/2009
MuCool RF Workshop-Fermilab
Muons, Inc.
9
Did Not Get
FIRM NAME:
Muons, Inc.
RESEARCH INSTITUTION:
Muons, Inc.
Fermi National Accelerator Laboratory
Milorad Popovic, subgrant PI
ADDRESS:
ADDRESS:
552 N. Batavia Ave.
Batavia, IL 60510
But Main Issues did not go away
Loss tangent tan d = 1/Qdielectric-1/Qair
Loss tangents of specially formulated alumina with TiO2 have been reported to be close
to sapphire at 1e-5 . So it is easy to see that today’s ceramics may be used in this novel
idea without suffering a great deal in cavity Q at low frequencies.
The other problem with ceramics in vacuum with beams is that of surface charging of
the ceramic. And again, much work has been done in coatings, from Chromium Oxide
to TiN to, more recently, ion implantation
Air gap between the dielectric and metal plates will be one of the issues that must be
tested experimentally
07/07/2009
MuCool RF Workshop-Fermilab
10
Main Issues
Muons, Inc.
•Ceramics, Loss Tangent
•Surface coating
•Dielectric Cooling/Tuning Liquid
•Geometric/Power Optimization
•RF and Mechanical Engineering
~50k$ + 1FTE to Start
07/07/2009
MuCool RF Workshop-Fermilab
11
Muons, Inc.
Other Applications
(Vacuum Cavities)
May be we can use this type of cavity for
Neuffer’s Phase Rotation Canal. This was
Cary Yoshikawa suggestion. The canal needs
many cavities in range from ~300 to 200MHz.
We can use, let say two sizes of Pill Box
Cavity (same size different dielectric!) and
adjust frequency in between using different
iner radius, re-entrant nose cones!
07/07/2009
MuCool RF Workshop-Fermilab
12
Muons, Inc.
Cavities for Neutrino Factory
Schematic of the Neutrino Factory front-end transport system. Initial drift (56.4 m),
the varying frequency buncher (31.5m), The phase-energy (-E) rotator (36m) , a
cooling section. (A 75m cooling length may be optimal.)
Parameter
Length (m)
Focusing (T)
Rf frequency (MHz)
Drift
Buncher
Rotator
Cooler
56.4
31.5
36
75
2
2
2
2.5 (ASOL)
360 to 240 240 to 202
201.25
Rf gradient (MV/m)
0 to 15
15
16
Total rf voltage (MV)
126
360
800
07/07/2009
MuCool RF Workshop-Fermilab
13
Muons, Inc.
Open Pill Box in Strong Magnetic field,
Vacuum Cavity
Vacuum
07/07/2009
MuCool RF Workshop-Fermilab
14
Muons, Inc.
07/07/2009
MuCool RF Workshop-Fermilab
15
Muons, Inc.
07/07/2009
MuCool RF Workshop-Fermilab
16
Muons, Inc.
t(ns)
E(MV/m) ConvInsu
1 104.27 23.366
501 30.01801 4.6643
1001 26.13199 3.898269
1501 24.09519 3.509672
2001 22.74676 3.257625
2501 21.7529 3.074633
3001 20.97312 2.932763
3501 20.33563 2.817927
4001 19.79908 2.722089
4501 19.33756 2.64026
5001 18.93382 2.569146
5501 18.57586 2.506466
6001 18.25497 2.45058
6501 17.96468 2.400269
7001 17.70002 2.354609
7501 17.45714 2.312882
8001 17.23295 2.274518
8501 17.02498 2.23906
9001 16.83119 2.206136
9501 16.64992 2.175437
10001 16.47975 2.146709
07/07/2009
MuCool RF Workshop-Fermilab
17
Muons, Inc.
Try to Establish Modeling Capability Locally
(E-Cool people, Lionel Prost)
07/07/2009
MuCool RF Workshop-Fermilab
18
Muons, Inc.
Geometry for electrostatic calculations
Length: 12 cm
I/M = 2
Upstream
electrode = -100
kV
Downstream
electrode = 100 kV
r = 7
I
Equipotentials:
DU = 4 kV
M
Based on Leopold et al.:
Optimizing the Performance of Flat-surface, High-gradient Vacuum
Insulators
07/07/2009
MuCool RF Workshop-Fermilab
19
Muons, Inc.
Electron trajectories calculations
Initial conditions:
- 10-6 keV (program
does not accept 0)
- No transverse
velocity
- Rini = 0.99 cm
(bore radius is 1 cm)
I
M
Trajectory for an
electron generated
at the metal
‘surface’
Trajectory for an
electron generated
at the insulator
‘surface’
07/07/2009
MuCool RF Workshop-Fermilab
20
Muons, Inc.
SuperFish
DielCav 400MHz, epsD=9.58 .00029 muD=1 F = 274.42166 MHz
14
14
12
12
10
10
8
8
6
6
4
4
2
2
0
0
-6
07/07/2009
-4
-2
0
2
4
6
8
10
C:\Documents and Settings\popovic\Desktop\DieCavSBIR\SBRCAV.AM 6-10-2009
MuCool RF Workshop-Fermilab
12
5:31:20
21
Main Issues
Muons, Inc.
•Ceramics, Loss Tangent
•Vacuum Surface Coating
•Dielectric Cooling/Tuning Liquid
•Geometric/Power Optimization
•Design, I/M Ratio
•RF and Mechanical Engineering
~50k$ + 1FTE to Start
07/07/2009
MuCool RF Workshop-Fermilab
22
Muons, Inc.
What is Next, 5-Years Plan
The projected funding for the 5-year program proposed here..
…We will also accomplish sufficient hardware R&D (RF, magnets,
and cooling section prototyping) to guide, and give confidence in,
our simulation studies.
In order to produce a practical helical cooling channel, several technical issues need to be addressed, including:
magnetic matching sections for downstream and upstream of the HCC a complete set of functional and
interface specifications covering field quality and tunability, the interface with rf structures, and heat load limits
(requiring knowledge of the power lead requirements)
To prepare the way for an HCC test section we would:
Develop, with accelerator designers, functional specifications for the magnet systems of a helical cooling
channel, including magnet apertures to accommodate the required rf systems, section lengths, helical periods,
field components, field quality, alignment tolerances, and cryogenic and power requirements. The specification
will also consider the needs of any required matching sections.
Perform conceptual design studies of helical solenoids that meet our specifications, including a joint rf and
magnet study to decide how to incorporate rf into the helical solenoid bore, corrector coils, matching sections,
etc.
07/07/2009
MuCool RF Workshop-Fermilab
23
(near)FUTURE
Muons, Inc.
(Vacuum Cavity)
oIn week or two
I hope, DC results with existing dielectric
oNuFact09-This Summer
I hope, RF(low power) results with low
loss dielectric
07/07/2009
MuCool RF Workshop-Fermilab
24
Muons, Inc.
Test Cavity
07/07/2009
MuCool RF Workshop-Fermilab
25
Muons, Inc.
07/07/2009
MuCool RF Workshop-Fermilab
26
Muons, Inc.
07/07/2009
MuCool RF Workshop-Fermilab
27