Post on 31-Dec-2015
description
New Technologies for Accelerators
- Advanced Accelerator Research -
Bob SiemannMarch 19, 2003
• Introduction
• An Incomplete Survey • Plasma Waves and The Afterburner• A Laser Driven Linear Collider• Conclusion
Science Innovation
Particle Physics Discoveries
• 2 ’s• J/• W & Z• top
Accelerator Innovations• Phase focusing• Klystron• Strong focusing• Colliding beams• Superconducting magnets• Superconducting RF
Innovation is Critical
The Livingston Curve• Captures our history• Expresses our aspirations• But there is no guarantee
• Approaches that have become too big, too expensive, … have been supplanted - Vital for advancing science
Accelerator Science & Technology
• Evolution & MaturityUnderlying science & technology
Developing a design => parameter lists, etc
Optimization
Construction
Commissioning & operation
Advanced accelerator research = high gradient e+e- acceleration
• Advanced accelerator research is one aspect of accelerator innovation
An Incomplete Survey
mm-wave accelerator
fabricated by deep x-ray lithography
R. Kustom et al, ANL
Dielectric wakefield accelerator – Two beam experiment
W. Gai et al, ANL
An Incomplete Survey
6 8 10 20 40 60 80100 200
103
104
105
106
Shot 12 (10 kG) Shot 26 (10 kG) Shot 29 (5 kG)Shot 33 (5 kG) Shot 39 (2.5 kG) Shot 40 (2.5 kG)
Re
lativ
e #
of
ele
ctro
ns/
Me
V/S
tera
dia
n
Electron energy (in MeV)
SM-LWFA electron energy spectrum
Self modulated laser wakefield acceleration
E > 100 MeV, G > 100 GeV/m
A. Ting et al, NRL
Active medium
Trigger bunch
Amplified wake
Accelerated bunch
Wakefield amplification by an
active medium
L. Schächter, Technion
An Incomplete Survey
Plasma Focusing of e+ beams
P. Chen et al, SLAC
0
50
100
150
200
250
300
-2 0 2 4 6 8 10 12
05160cedFit.2.graph
X
DS
OT
R (µ
m)
K*Lne1/2
0 uv Pellicle
=43 µm
N
=910-5 (m rad)
0=1.15m
Transport of an e- beam through a 1.4 m long
plasma
P. Muggli et al, USC
Advanced Accelerator Physics at SLACAdvanced Accelerator Physics at SLAC
T. Katsouleas, S. Deng, S. Lee, P. Muggli, E. OzUniversity of Southern California
B. Blue, C. E. Clayton, V. Decyk, C. Huang, D. Johnson, C. Joshi, J.-N. Leboeuf, K. A. Marsh, W. B. Mori, C. Ren, J. Rosenzweig, F. Tsung, S. Wang
University of California, Los Angeles
R. Assmann, C. D. Barnes, F.-J. Decker, P. Emma, M. J. Hogan, R. Iverson, P. Krejcik, C. O’Connell, P. Raimondi, R.H. Siemann, D. R. Walz
Stanford Linear Accelerator Center
UCLA
Beam-Driven Plasma Acceleration: E-157, E-162, E-164, E-164X
C. D. Barnes, E. R. Colby, B. M. Cowan, M. Javanmard, R. J. Noble, D. T. Palmer, C. Sears, R. H. Siemann, J. E. Spencer, D. R. Walz
Stanford Linear Accelerator Center
R. L. Byer, T. Plettner, J. A. WisdomStanford University
T. I. Smith, R. L. Swent Y.-C. Huang Hansen Experimental Physics Laboratory National Tsing Hua University, Taiwan
L. SchächterTechnion Israeli Institute of Technology
Vacuum Laser Acceleration: LEAP, E-163
Physical Principles of the PlasmaPhysical Principles of the Plasma Wakefield Accelerator Wakefield Accelerator
• Space charge of drive beam displaces plasma electrons
• Wake Phase Velocity = Beam Velocity (like wake on a boat)
• Plasma ions exert restoring force => Space charge oscillations
• Wake amplitude Nb z2
( for 4z p 1
no
)
++++++++++++++ ++++++++++++++++
----- --- ----------------
--------------
--------- ----
--- -------------------- - --
---- - -- ---
------ -
- -- ---- - - - - - ------ - -
- - - - --- --
- -- - - - - -
---- - ----
------
electron beam
+ + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +-
- --
--- --
EzEz
Z
Rad
ius
electron
positron
Flow-in
Blow-out
e+
e-
Rad
ius
Electrons and Positrons in Plasmas
� Double the energy of Collider w/ short plasma sections before IP
� 1st half of beam excites wake --decelerates to 0� 2nd half of beams rides wake--accelerates to 2 x Eo
� Make up for Luminosity decrease N2/2 by halving in a final plasma lens
50 GeV50 GeV ee--
50 GeV50 GeV e e++e-WFA e+WFA
IP
LENSES
The Afterburner IdeaThe Afterburner Idea
Located in the FFTB
Experimental Layout for Beam Plasma Experiments
Runs 2&3, Summer 2001e+ acceleration, e- acceleration
-200
-150
-100
-50
0
50
100
150
200
-6 -4 -2 0 2 4 6 8
SliceEnergyGain.graphn
e=1.31014 (cm-3)
ne=1.61014 (cm-3)
ne=2.01014 (cm-3)
ne=(2.3±0.1)1014 (cm-3)
Rel
ativ
e E
nerg
y (M
eV)
(ps)
+z
+2z
+3z
-2z
-z
• Average energy loss (slice average): 159±40 MeV• Average energy gain (slice average): 156 ±40 MeV
E-162: Longitudinal Dynamics Part 4Preliminary Energy Loss & Gain
An e+e- Linear Collider
L, ECM
e+ e-Damping Ring
Power Source
Final Focusing SystemLinear Accelerator
Particle Source
Luminosity, Beam Power & Efficiency
214 c
x y
NL f
2b cP Nf mc
bL P
particles per bunch
, transverse beam sizes
collision frequency
single beam power
energy in units of rest energy
x y
c
b
N
f
P
2AC
b accelerating stpowe ructr s urource eP
P efficiency
Efficiency and Scalability of Power Sources
TUBES FEMs FELs LASERS(RF Compression, modulator losses not included)
Yb:KGd(WO4)2
=1.037t=112 fsecPave=1.3 W=28%
SLAC PPM Klystron=2.624 cmt=3 secPave=27 kW=65%
Source Frequency [GHz]
Sou
rce
Eff
icie
ncy
[%]
Carrier Phase-Lock of a Laser
M. Bellini, T Hansch, Optics Letters, 25 (14), p.1049, (2000).
Eric Colby10/15/2002
Carrier Phase-Locked Lasers Diddams et al
“Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb”, Phys. Rev. Lett., 84 (22), p.5102, (2000).
Luminosity, Beam Power & Efficiency
214 c
x y
NL f
2b cP Nf mc
bL P
particles per bunch
, transverse beam sizes
collision frequency
single beam power
energy in units of rest energy
x y
c
b
N
f
P
2acceleratinAC
b power sou g structurerceP
P efficiency
Structure Efficiency 2Cbeam H
laser
PZU qL qcZU P
q = 0, because no charge is accelerated
C
H
PZq
cZ
because 0 , 0wakeG G G
0G G
max 4C
H
ZLc Z
when max 2C
H
PZq q
cZ
= 0
= max
= 0All the laser energy radiated away into broad band radiation
q/qmax
/max
PBGFA Efficiency max 4 1g C
H g
Z
Z
max 2C
H
PZq q
cZ
X. Lin, Phys. Rev. ST-AB, 4, 051301 (2001).
19.5CZ
0 20
1130
2 /HZ Z
r
0 0.678 radius of beam tunnelr
The estimate of ZH ignores the other air tunnels and the frequency dependence of the dielectric constant
4max
0
max
10.4 6.5 10 '
30
40 sec
0. /
5.2%
77
q f
P kW
p
G GeV
e s
m
C
max
4 5
2
10 10 '
C
H
PZq q
cZ
e s
Charge Limit
1. There is a maximum charge/bunch based on efficiency
2. It is uncertain because ZH is uncertain• PBGFA: frequency dependence of • LEAP: multiple slit interference
3. Multiple beam bunches/laser pulse• Required for high efficiency• PBGFA: is already long to fill
structure => make it slightly longer to accelerate multiple bunches
• LEAP: >> min => accelerate multiple bunches or waste energy
Concluding Remarks Recycling (M. Tigner). All laser based schemes rely on the fact that a relatively
small fraction of the energy stored in the laser cavityenergy stored in the laser cavity is extracted and used in the acceleration structureacceleration structure. Conceptually, it seems possible to take advantage of the high intensity electromagnetic field that develops in the cavity and incorporate incorporate the acceleration structure in the laser cavitythe acceleration structure in the laser cavity.
According to estimates, the rep-rate of each macro-bunch is 1GHz and each macro-bunch is modulated at the resonant frequency of the medium (e.g. 1.06m).
The amount of energy transferred to the electrons or lost in the circuit is compensated by the active mediumcompensated by the active medium that amplifies the narrow band wakenarrow band wake generated by the macro-bunch.
Acceleration Structure
Acceleration Structure
Active Medium
Active Medium
Acceleration Structure
Active Medium
Active Medium
Acceleration Structure
Levi Schächter10/11/02
(But not for this talk)
A Parameter List
ECM = 500 GeV Laser JLC/NLC N 5106 9.5109 fc 50MHz 11.4kHz Pb (MW) 10 4.5
x/y (nm) 0.5/0.5 330/5 N 0.22 1.1
z (m) 120 300
z/c (psec) 0.4 1 0.045 0.11 L 11034 5.11033
Beam is assumed debunched at the
IP
An e+e- Linear Collider
L, ECM
e+ e-Damping Ring
Power Source
Final Focusing SystemLinear Accelerator
Particle Source
STELLA (Staged Electron Laser Acceleration) experiment at the BNL ATF
C O 2 la se r be a m
E L E C T R O NS P E C T R O M E T E R
IF E LA C C E L E R ATO R IF E L
B U N C H E R
4 6 M e V 0 .5 n C 2 m m m ra d 3 .5 p s
0 .6 G W , 1 80 p s
Steeringcoil
BPM
BPM
BPM
BPM
Focusingquadrupo les
S teeringcoil
Focusingquadrupo les
Source: W. Kimura, I. Ben-Zvi.
Bunching & Phase ControlAt = 10 m
Particle Source
10 MW @ 500 GeV 1.251014 particles/second106 – 107/ 1 psec long bunch spaced at 50 MHz
~100 optically spaced bunches in the 1 psec bunch
Bunches spaced at harmonic of 50
MHz
IFEL to bunch and accelerate at
Continuous injection
Low energy for low I and to have IFEL bunchingDo not know how to extract!
Science Innovation
Advanced Accel. R&D