High-Frequency “Adiabatic” Buncher
Download
Report
Transcript High-Frequency “Adiabatic” Buncher
μ-Capture, Energy Rotation, Cooling
and High-pressure Cavities
David Neuffer
Fermilab
0utline
Motivation
Study 2AP Neutrino factory …
Muon Collider, …
“High-frequency” Buncher and Rotation
Study 2Ap scenario, obtains up to ~0.2 /p
Integrate cooling into phase-energy rotation
Gas-Cavity Variations
Cooling in bunching and phase rotation
Higher gradient, lower frequency ???
Shorter system, fewer bunches
Optimization ….
Polarization
Use high gradient rf near target to improve
polarization
2
Advantages of high-pressure cavities
high gradient rf
In magnetic fields B=1.75T,
or more …
With beam
Change cavity frf by
Can Integrate cooling with
capture
Capture and phase-energy
rotation + cooling
Can get high-gradient at
low frequencies (30, 50,
100 MHz ???)
Beam manipulations
Polarization
Research can be funded…
3
Study2A Dec. 2003June2004
Drift –110.7m
Bunch -51m
V’ = 3(z/LB) + 3 (z/LB)2 MV/m
(× 2/3) (85MV total)
(1/) =0.0079
-E Rotate – 52m – (416MV total)
12 MV/m (× 2/3)
P1=280 , P2=154 V = 18.032
Match and cool (100m)
V’ = 15 MV/m (× 2/3)
P0 =214 MeV/c
0.75 m cells, 0.02m LiH
4
Study2AP June 2004 scenario
Drift –110.7m
Bunch -51m
V(1/) =0.0079
12 rf freq., 110MV
330 MHz 230MHz
-E Rotate – 54m – (416MV total)
15 rf freq. 230 202 MHz
P1=280 , P2=154 NV = 18.032
Match and cool (80m)
0.75 m cells, 0.02m LiH
“Realistic” fields, components
Fields from coils
Be windows included
5
Simplest Modification
Add gas + higher gradient to
obtain cooling within rotator
~300MeV energy loss in
cooling region
Rotator is 51m;
Need ~6MeV/m H2 Energy loss
9MeV/m if cavities occupy 2/3
~30% Liquid H2 density
Alternating Solenoid lattice in
rotator
21MV/m rf
Try shorter system …
Cool here
6
Short bunch train option
Drift (20m), Bunch–20m (100 MV)
Vrf = 0 to 15 MV/m ( 2/3)
P1 at 205.037, P2=130.94
N = 5.0
40m
Rotate – 20m (200MV)
N = 5.05
Vrf = 15 MV/m ( 2/3)
Palmer Cooler up to 100m
60m
Match into ring cooler
ICOOL results
0.12 /p within 0.3 cm
Could match into ring cooler
(C~40m) (~20m train)
95m
BunchRotate
(20m) (20m) Cool (to 100m)
Drift (20m)
7
FFAG-influenced variation – 100MHz
100 MHz example
90m drift; 60m buncher, 40m
rf rotation
Capture centered at 250 MeV
Higher energy capture
means shorter bunch train
Beam at 250MeV ± 200MeV
accepted into 100 MHz buncher
Bunch widths < ±100 MeV
Uses ~ 400MV of rf
8
Lattice Variations (50Mhz example)
Example I (250 MeV)
Uses ~90m drift + 100m
10050 MHz rf (<4MV/m)
~300MV total
Captures 250200 MeV ’s into
250 MeV bunches with ±80 MeV
widths
Example II (125 MeV)
Uses ~60m drift + 90m 10050
MHz rf (<3MV/m) ~180MV total
Captures 125100 MeV ’s into
125 MeV bunches with ±40 MeV
widths
9
Polarization for μ+-μ- Colliders
Start with short proton bunch
on target < ~1ns
Before π⇒μ+ν decay, use
low-frequency rf to make
beam more monochromatic
~50MV in ~5m?
Drift to decay (~10m?)
+
Higher energy μ’s pol. +
Lower energy μ’s pol. –
-
¼ Phase-Energy rotation
~10m
Rebunch at ~2× frequency
+’s in one bunch
-’s in other bunch
+
-
10
Summary
High-frequency Buncher and E Rotator (ν-Factory)
improved (?) with high-pressure cavities
Shorter systems
Lower Frequency (fewer bunches).
μ+-μ- Colliders …
Polarization …
To do:
Optimizations, Best Scenario, cost/performance …
11
Current Status (New Scientist)
(or μ+-μ- Collider)
12
DoE/NSF today …
13