beam diagnostics and radiation detection system
TRANSCRIPT
BEAM DIAGNOSTICS AND
RADIATION DETECTION
SYSTEM
Alexander S. Aryshev, Ph.D.
Assistant Professor
KEK: High Energy Accelerator Research Organization,
1-1 Oho, Tsukuba 305-0801, Ibaraki-ken, Japan.
TEL: +81-298-64-5715, FAX: +81-298-64-0321.
e-mail: [email protected]
3rd international school on Beam Dynamics and Accelerator technology, 25 Feb. – 3 Mar. 2021
Outline • Introduction
• Transverse Parameters Measurements – Monitor beam position (BPMs)
– Monitor beam charge (CTs)
– Wire scanners
– Laser-wires
– Monitor beam profile (Screens)
– EM radiation review
– OTR/ODR
• Longitudinal Parameters Measurements – RF deflector
– Coherent radiation theory
– CTR/CSPR
– GHz/THz detectors
– GHz/THz interferometers
– Bunch shape reconstruction
• Additional references
• Summary
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
General review • Accelerator performance depends critically on the ability to
carefully measure and control the properties of the accelerated
particle beams.
• This reflects in part the increasingly difficult demands for high
beam currents, smaller beam emittances, and the tighter
tolerances placed on these parameters (e.g. position stability) in
modern accelerators.
• A good understanding of diagnostics (in present and future
accelerators) is therefore essential for achieving the required
performance.
• A beam diagnostic consists of the measurement device
associated electronics and processing hardware.
• “Beam Diagnostics and Applications”, A. Hofmann (BIW 98)
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Why it is a big deal?
• Good knowledge of accelerators, general physics and technologies needed.
• Quite different technologies are used, based on various physics processes.
• Each task and each technology calls for an expert.
• Applicability (in term of a reliable results) of various diagnostics types greatly depends on machine type, particles types and beam parameters.
• Well established techniques are not always applied.
• Quick, remotely controlled, on-line, non-destructive, multifunction and possibly single-shot measurements needed.
• Accelerator development goes parallel to diagnostics development.
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Typical linear accelerator beamline
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02 March 2021 3rd international school on Beam Dynamics
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Diagnostic devices and beam properties
measured
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Effect on beam: • “N” – none • “-” – negligible • “+” – perturbing • “D” – destructive
• “” – primary purpose
• “” – indirect use
Diagnostic of High Brightness Electron
Beams HB E-beam diagnostic
General: •bunch charge
FC, ICT, Toroids
•transverse position
BPM: button, stripline,
cavity
•arrival time (phase)
BAM, RF pickups
Projected Slice
Longitudinal
(temporal)
Transverse
Current
profile
Energy
distribution
Long.
phase
space
Slice
energy
spread
Slice
emittance
Proj.emittance,
transv. phase
space
Transverse
profile
ynxn
n
IB
Challenges • high charge / charge
density
• small beam dimensions
(100…50um nm!)
• high repetition rate
• all the intercepting devices
are damaged by measured
beams
• beam halo measurements
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Transverse Parameters Measurements
• OTR monitors (~um Al foil)
– High energy (>tens of MeV)
– No saturation
– Resolution limit closed to optical diffraction limit (~10um)
– COTR effects (especially for compressed bunches)
• Scintillator screens (e.g. YAG:CE, 100um)
– High photon yield
– Resolution grain dimensions (~50um?) (powder / thin crystal)
– Saturation (0.04pC/um^2?)
• Wire Scanner (good agreement with YAG measurements!)
– Almost non-invasive
– Higher beam power
– Multi-shot measurements
– 1D
– Rather complicated setup, long measurement time
• Diamond screen long pulse train
• “Indirect” (SR – Optical Synchrotron Interferometry, Scattering, ODR, etc)
Usually the largest error in transverse parameters measurements is coming from transverse
profile and rms size determination.
Readout:
•Zoom optics
•CCD camera
• 12bit
• l~ 1um..400nm
• controllable iris
•Insertable filters
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Transverse Phase Space (Emittance)
Measurements
Space charge
dominated
Emittance dominated
Slit mask techniques:
• based on
conversion of a
space charge
dominated beam into
emittance dominated
beamlets
•Multi screen:
•Based on linear beam matrix
approach
•3 beam size measurements (at
3 positions) are needed for the
known elements of the transport
matrix (phase advance)
•Quad(s) scan
•Beam size measurements as a
function of varied transport
matrix
•Tomography
•Related to Radon theorem: N-
dim object reconstruction from M
projections in (N-1) dim space
• Systematic error from quad
strength determination
(e.g hysteresis)
• Thin lens model is not
adequate
• Large energy spread
chromatic effects
• Phase space distribution
assumed to be homogeneous
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Slit technique - general
-2 -1 0 1 2-30
-20
-10
0
10
20
30
x
px
Transverse phase space reconstruction
L
Space charge
dominated beam
Emittance
dominated
beamlets
222 xxxxnx
•Slit mask:
• Opening: small enough
• Thickness: thick enough to scatter beam, but
alignment / angle acceptance
•Distance L:
•Long enough divergence resolution
•Not too long signal-to-noise
Multi slit mask = single shot measurement, but:
•Overlapping of beamlets when optimized for high resolution
•Low sampling of the phase space
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Transverse projected emittance measurements at PITZ
EMSY1 (z = 5.74 m) Observation
screen
2.64 m
Single slit scan technique
> Emittance Measurement SYstem (EMSY) consists of horizontal / vertical actuators with
YAG / OTR screens
10 / 50 m slits
> Beam size is measured @ slit position using screen
> Beam local divergence is estimated from beamlet sizes @ observation screen
> 12-bit camera, quality criteria: max bit>3000 (from 4095=2^12-1); adjustment = gain X NoP
> Image filtering (3sigma, bkg, x-ray, MOI) 2D scaled normalized RMS emittance
222
2xxxx
x
xn
x - RMS beam size measured with YAG screen at
slit location
SQRT(<x2>) - RMS beam size at slit location
estimated from slit positions and beamlet intensities
“100% RMS emittance”
scale factor ( >1 ) introduced to correct for low
intensity losses from beamlet measurements
pixel intensity
transverse phase space beam at EMSY screen
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Beam Position Monitors (BPMs)
• Used in high intensity machines with short bunches and Synchrotron light sources.
• The BPM consists of four metal buttons on the inside of the accelerator structure, connected to wires that extend outside the structure and are grounded.
• The entire apparatus is electrically isolated from the accelerator structure itself.
• The information from the four buttons can be used to measure the number of electrons in the bunch and determine the position of the bunch.
• Buttons are used frequently in synchrotron light sources are a variant of the capacitive monitor.
• Picks up the wall currents at several positions
• Huge dynamic range but poor resolution ~10um (typ.)
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Beam Position Monitors (BPMs)
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Stripline BPM
• Stripline has 4 strips running along the axes of beam, parallel to the vacuum chamber wall.
• The length of the strip is usually longer than the characteristic bunch length and equal to quarter wavelength of fundamental RF.
• The electromagnetic field of the beam induces signal on the strip line.
• The amplitude of signal is a function of its solid angle subtended on the beam and distance of the conductor from the beam.
• Two ends of the stripline are taken out of the chamber. These are called upstream and downstream ports respectively with reference to the beam direction.
• Better resolution <10um
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Much better for a short bunches
LUCX BPMs
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Current transformers
• Simple design
• Of-the-shelf availability
• Fast response
• Femtosecond bunch
generates good signal
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WIRE SCANNER
• Device with a thin fiber (tungsten or carbon) moving across the transverse section of the beam.
• Interception of the beam produces bremsstrahlung photons and secondary emission electrons. Either rays or secondary e- can be used for the information on beam profiles (Hor. & Ver.).
• The W.S. is attached to a precision stepped device moving with m steps.
• The rms resolution of a W.S. is d/4, where d, is the wire diameter.
• For example, a 5 m rms beam measurement would be widened by only 6% , with a 7 m diameter W.S.
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Some details on Wire Scanners
• Usually, two wires (H&V) are
mounted on a fork which is
displaced at 45 degrees to the
horizontal plane.
• In some cases, the rays are
converted into pairs which create
Cherenkov Radiation in a
medium (ex. SLAC/FFTB).
• Minimum diameter size actually
realized is of 4 m, leading to a
minimum resolution of 1 m.
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LASER WIRE MONITOR
• Principle : Compton scattering of the electron beam by a laser
light sent at right angle to the beam. The emitted (hard)
photons are measured in the forward direction.
• The laser beam waist is realized in the center of a Fabry-Perot
cavity (low power laser) or without the cavity (high laser energy
per pulse)
• The counting rates of scattered photons are measured as a
function of the laser-wire position
• The actual electron beam profile is obtained after
deconvolution with the known laser distribution
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Laser Interferometer Technique
• This technique, used by T.Shintake at FFTB, uses
interferometry technique with a YAG-laser beam split into two
beams which collide, perpendicularly, with an electron beam.
The Compton back scattered , in the forward direction (e-) are
directed to a -detector (Conv. + gas Cerenkov). As the laser
light is producing a fringe pattern, the ’s present periodic
variations with llaser along laser axis, when scanning the beam.
Modulation depth=> size
• This technique allows high accuracy;
– a 60 nm spot (V) was measured at FFTB.
– a 40 nm (V) was measured at KEK ATF
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Screen monitors
• Incoherent light monitors
– Luminescent screens
– Optical Transition Radiation (OTR) monitor
– Optical Diffraction Radiation (ODR) monitor
– Cherenkov radiation monitors
• Coherent light monitors
– Coherent Transition Radiation (CTR)
– Coherent Diffraction Radiation (CDR)
– Coherent Cherenkov Radiation (CChR)
– Coherent Resonant Diffraction Radiation (so-called Smith-Purcell radiation, CSPR)
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KEK LUCX Screens
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LUCX Screens
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UV
e-beam
Luminescent screens
• When a beam passes through a luminescent screen, part of the deposited energy results in excited electrostatic states in the material from which a light emission at a defined wavelength will follow.
• The light emission originates in impurity inclusions, the so-called activators, in most of the used materials.
• They allow a direct observation of the beam position and shape on a TV monitor.
• They are necessarily single-pass monitors.
• Not very accurate
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courtesy: Gérard Burtin (CERN).
Beam Profile Monitors (Screens)
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courtesy: H. Koziol (CERN).
• Profile, roll • Position • Charge • Energy • Energy spread
For Bunch length or Bunch profile one have to take into account transverse beam size.
V.L. Ginzburg and I.M. Frank, Zh. Eksp. Teor. Fiz. 16 (1946) 15.
Types of radiation
Electromagnetic radiation generated by charged
particles can be divided into two categories:
– Bremsstrahlung (gas, plasma); radiation of hard
photons due to acceleration (synchrotron radiation,
undulator rad., channeling rad., etc.)
– Polarization radiation (radiation of soft photons;
acceleration is not required (Vavilov-Cherenkov
rad., Transition rad., etc.);)
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Polarization Radiation (PR)
• Macroscopic treatment of PR began from works on
– Vavilov-Cherenkov radiation, VChR (Cherenkov, 1934; Tamm, Frank, 1937),
– Transition radiation, TR (Ginzburg, Frank, 1945),
– Difraction radiation, DR (Bobrinev, Braginsky, 1958; Dnestrovsky, Kostomarov, 1959),
– Smith-Purcell radiation, SPR (Smith, Purcell, 1953),
– and this is not the end of the list...
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Transition Radiation
• Transition radiation is created
when a charged particle crosses the
interface between two media of
different optical properties.
• The radiation is emitted in two
directions:
• Forward: in direction of beam
propagation
• Backward: in direction of specular
reflection.
• Wide wavelength range OTR can be used for transverse beam profile measurements.
• Silicon screens + Ag or Al coating.
• Often beams are far from Gaussian especially in LINACs.
• Camera must be protected from radiation requiring a complex optical lines.
• Filters are needed to avoid saturating the camera.
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Transition Radiation: possible measurements
• Bunch length: due to the rapid formation of the radiation (~10E-13 s), it is possible to measure very short bunches:
– With a Streak-Camera (SC): the limitation is brought by the SC resolution (~ps)
• With coherent TR using wavelengths comparable to the bunch size:
– resolution < ps
• Transverse phase space:
– transverse dimensions are measured with CCD cameras at the image plane of the lens
– angular distributions are measured with a CCD camera at the focal plane of the lens.
• Beam energy:
– determined by the angular position of the maxima (1/)
– … or just a transverse size in the dispersion section.
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Backward TR (horizontal polarization)
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22 22
2 2 2 2 2
sin cos sincos
(1 sin cos sin ) cos cos
dW e
d d c
16
02 March 2021
Backward TR (vertical polarization)
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22 22
2 2 2 2 2
cos sin sincos
(1 sin cos sin ) cos cos
dW e
d d c
16
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Backward TR
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dW dW dW
d d d d d d
16
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1. D.V. Karlovets and A.P. Potylitsyn, JETP Lett. 2009, Volume 90, Number 5, Pages 326-331
2. D. V. Karlovets, JETP, 2011, Volume 113, Number 1, Pages 27-45
Transition Radiation: some activities at LAL-Orsay
• The more “recent” activities with OTR in LAL, concerned:
– a test on the OTR resolution on the 2 GeV Orsay e- linac
On figure H profile, =0.3 mm
– a series of measurements on the Tesla Test Facility (TTF) at DESY. In that case, beam emittance has been determined and observations on beam behavior inside the pulse, also.
-> PhD report of A.Variola
M. Castellano and V. A. Verzilov, PRST-AB 1, 062801 (1998)
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Study of OTR resolution
• Theoretical & Experimental studies to determine resolution
• Theoretical: Rule&Fiorito, X.Artru et al, M.Castellano
PhD thesis (K.Honkavaara: Orsay)
{Figure from PhD report of KH}
• Experiments at LAL-Orsay (2 GeV), CEBAF (4 GeV) and CERN (22 GeV), showed an OTR resolution << l
• => practical resolution: FWHM
• of the diffraction function
• => OTR measurements of small beams at high energy: possible
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Beam size effect on OTR
“Usual” OTR image
OTR vertical polarization
component,
for sigma < ~15* um
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OTR image and Quadrupole scan.
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100um
Pavel Karataev, Alexander Aryshev, Stewart Boogert, David Howell, Nobuhiro Terunuma, and Junji Urakawa Phys. Rev. Lett. 107, 174801 – Published 17 October 2011
FFTB Single Pulse Damage Coupon Test - front and back side - same scale
Front
Front
Front
Front
Back
Back
Back
Back
2 1010 8 x 6 m
2 1010 8 x 6 m
2 1010 9 x 8 m
2 1010 9 x 11 m
Four pairs of single pulse damage holes front and back
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Diffraction Radiation
• Small recall:
As for Cherenkov Radiation and Transition Radiation, the
Diffraction Radiation was studied by Russian theoreticians
Papers from 1958 (Y.Dnestrovskii and D.Kostomarov), analysed
the radiation of a beam of particles passing through a circular
aperture. Later, in 1962, A.Kazantsev and G.Surdovich studied
the radiation of a particle beam, close to a metal screen. They
considered this radiation as resulting from the diffraction of the
electromagnetic field of the particle by the metal screen.
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Diffraction Radiation: a simple approach
• We can consider the DR as
resulting from the diffraction of
the virtual photon flux by the
aperture (hole, slit, edge).
[Figure from Moran in NIMB]
• The source of DR is a “disk” of
diameter l/2. Consider a slit of
aperture a:
* l<<2a =>DR radiation ~0
* l>>2a =>DR similar to TR
* l ~ 2a =>DR intensity<TR,
but enough for measurement
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Principle:
1. Electron bunch moves through a high precision co-planar slit in a conducting screen (Si + Al coating).
2. Electric field of the electron bunch polarizes atoms of the screen surface.
3. DR is emitted in two directions: – along the particle trajectory “Forward Diffraction
Radiation” (FDR)
– In the direction of specular reflection “Backward Diffraction Radiation” (BDR)
Diffraction Radiation
θ0
θy
e-
DR Angular distribution
Impact parameter:
ℎ ≤𝛾𝜆
2𝜋
Generally: DR intensity ⇧ as slit size ⇩
h
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Diffraction Radiation: status
• Theoretical works made a while ago (Ter-Mikaelian,..)
– More recent calculations by Moran, Rule and Fiorito, Castellano, Potylitsin, Artru
• Measurements (few) are concerning :
– bunch length measurements (coherent DR; l~mm); Y.Shibata et al
– transverse beam characteristics (slit 1mm, l=1.6 m) at ELETTRA
(team M. Castellano) and DESY (A.Cianchi, M.Castellano, G.Kube et.al)
• At KEK ATF (P. Karataev, et.al.), with an inclined edge at some
tens of m of beam axis. Detection of optical l for 1.28 GeV
e- beam (angular distribution).
Note: as for TR, the DR resolution depends on the optical acceptance
Due to its non-invasive character, DR will have large developments
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Pavel Karataev, Sakae Araki, Ryosuke Hamatsu, Hitoshi Hayano, Toshiya Muto, Gennady Naumenko, Alexander Potylitsyn, Nobuhiro Terunuma, and Junji Urakawa Phys. Rev. Lett. 93, 244802 – Published 8 December 2004
Vertical polarisation component of 3-dimensional (θx, θy, Intensity) DR angular distribution.
PVPC is obtained by integrating over θx to collect more photons.
Visibility (Imin/Imax) of the PVPC is sensitive to vertical beam size σy.
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Source of background Contribution
SR from beamline optics High
Camera noise Low
Residual background
SR + DR interference
SR suppression
P. Karataev et al., Proc. of EPAC 2004, THPLT067
θ0
θy
e-
Use a mask upstream of target to suppress SR contribution.
E = 2.1 GeV λ = 400 nm a = 0.5 mm
Mask Target
OTR ODR
Diffraction Radiation measurements background
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Summary: comparison of different methods
Methods Invasive ? Limit (m) Defined by Intense beam
OTR (rms) yes ~ 5 CCD pixel size
+optics
no
OTR (PSF) yes < 1 CCD sensitivity +
Optical background
no
ODR no ~ 9 CCD pixel size
+optics
yes
Wire scanner yes ~ 4 Wire diameter no
Laser wire
(cavity)
no < 1 Laser (l) +
Cavity mode
yes
Laser-wire
(high E)
no < 1 Laser (l) +
transverse beam
quality, FF lens
yes
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Bunch length measurements
• Direct time-of-flight measurements – Streak camera (Profile reconstruction, Single Shot, Expensive, Space-
charge limited)
– Deflecting cavity (Same as above)
– Cavity-BPM (preliminary) (RMS relative length change, Calibration?)
• Electro-optical methods – Profile reconstruction, Single shot
– http://www-library.desy.de/preparch/desy/thesis/desy-thesis-11-017.pdf
• Methods based on coherent spectrum – Spectral measurements
• Longer wavelengths
• Lack of broadband detectors
• Care is needed (absolute calibrations, linearity, spectral response)
– Bunch profile reconstruction • Complicated mathematics
• Dependence on radiation generation mechanism
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Longitudinal Parameters Measurements
Temporal beam profile (bunch length) r(t)
Time Domain Frequency Domain Optical and laser techniques
Radiator +
Streak-
camera
RF
deflector
Coherent radiations +
Interferometer
Cherenkov
Laser Wire
•Non intercepting and not disturbing
•Multi shot
•Complicated setup
•Interferometers (Michelson; Martin-Puplett)
•Spectrum acceptance is restricted can
impact the reconstructed beam profile
•Guess distribution is needed
Intercepting diagnostic
•Radiators
•OTR (Al foil)
•Cherenkov (aerogel)
•Streak camera
•T-resolution limited to 200...300 fs
•Rather expensive
•Light collection \transport
dispersion free beam line is
needed (reflective optic instead of
lens)
Transition = CTR
Synchrotron CSR
Smith-Parcell
Diffraction = CDR
Electro Optical Sampling = EOS
•Non intercepting and not disturbing
•Based on optical properties of a
non-linear crystal interacting with
Coulomb field of e-beam
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Longitudinal Parameters Measurements: RF deflector
RF Deflector:
•Self calibration (cavity phasing)
•Single shot
•Intercepting diagnostic
•Resolution down to tens of fs (f, V, tr)
•small transverse beam size and large beta function
•uncorrelated transverse energy spread
•induced slice energy spread
•phase jitter of the beam w.r.t. RFD
Map time (longitudinal) axis onto transverse coordinate
OTR beam images in the LCLS injector at 135MeV
for a 800um long bunch with the deflecting cavity off
(left) and on at 1MV (right).
H. Loos, “Longitudinal diagnostics for short electron
beam bunches”, SLAC-PUB-14120
RFD off RFD on
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Longitudinal phase space measurements Spectrometer dipole RFD (Energy scale from beam in spectrometer, time scale with
transverse deflector)
Fast single shot measurements
LCLS: 135 MeV SPARC: 145MeV
Imaging of longitudinal phase space with RF deflector
E
t
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Screen monitors
• Incoherent light monitors
– Luminescent screens
– Optical Transition Radiation (OTR) monitor
– Optical Diffraction Radiation (ODR) monitor
– Cherenkov radiation monitors
• Coherent light monitors
– Coherent Transition Radiation (CTR)
– Coherent Diffraction Radiation (CDR)
– Coherent Cherenkov Radiation (CChR)
– Coherent Resonant Diffraction Radiation (so-called Smith-Purcell radiation, CSPR)
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x
y
z
L
rx
e-
y
n
e1
b1
e2
o
Theory of Coherent radiation
l
,1 zFNNNd
dPP
Radiative power of CSR emitted by a bunch of electrons
])/(4exp[2exp2
exp2
1, 2
2
2
2
2l
l
l z
zz
z dzz
iz
F
L
dtc
Rti
n
nne
E 0 2
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exp
124
Fourier transform of the electric field of a moving charge (so-called Lienard-Wiechert potentials for a moving charge)
yxyyxn coscos,sin,cossin
rr
LL cos,0,sin
r
l
l
L
xy
Ln
L
c
Rt
coscos12
12
0,0,11 b
nbe
12nee
21
1
eEEHor 2
eEEVer
sincosexp1exp
ii
t
Ri
J.S. Nodvick and D.S. Saxon, Phys. Rev., 96, (1954), 180
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yxVerVer
dddd
Pd
d
dPx
x
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2
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,1 zHor
Coh
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Theory of Coherent radiation
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TR 3D Form-Factor
the form factor for TR has view:
22
( ) exp sin zkf k k r
where – wave number, - observed angle, -the velocity of
electron in the units of speed of light k
2 2
2 2
1 ( )( , ) exp
2 2
x yg x y
r r
2
2
1( ) exp
22 zz
zh z
For a Gaussian bunch with transverse distribution
and the longitudinal distribution
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Coherent radiation Spectrum
22 2|| 2
2 2 2 2 2
sin cos sin( ) cos
(1 sin cos sin ) cos cos
edW d d
c
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Propagation of power Interference factor of the grating Structural factor of the grating
Smith – Purcell radiation
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ve
h
d a
0
k k
q = 2q0ln =
d
n
1
b- cosq
æ
èç
ö
ø÷
ratio = da
22semiplaneRDR
cell N
d Wd WF F
d d d d
Radiation distribution from a semiplane
Strip (cell) geometry factor
Interference factor
2 24 sinh se ixp n22
cellF
0 0 2 2sins
1/ co
x
a
l
0
0
0/ cos2 coscos y
a
l
00
new
00; 2x y
Direction of the mirror reflection from a strip.
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Smith – Purcell effect as resonant diffraction radiation, A.P. Potylitsyn, NIM B 145 (1998) 60 – 66.
x
y
θ =0 deg;
θ =90 deg;
γ=20;
h=0.15 mm;
a=d=12 mm;
N=20
Optimization of the strip tilt angle
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Pyroelectric detector
Bolometer
Golay cell detector
Rectifier-type detector
Time Constant (Not measured for each detector) ~ 1 microsecond (depending on conditions of measurement) 02 March 2021
3rd international school on Beam Dynamics
and Accelerator technology
Bolometer and Pyroelectric detectors
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Golay cell and Diode detectors
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Injection 1-st turn 2-nd turn
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
SB
D, V
0.00 460 920 1380
Time, s n
a
-2 0
Time, s n
-0.005
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
SB
D, V
-1 21
Figure 5a. Typical Oscilloscope traces of
the SBD signal for the ATF DR injection.
Typical SBD oscilloscope trace
1 ns
Radiation pulse duration is ~ 10 ps !!!
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
0.00 1.20x10-7
2.40x10-7
3.60x10-7
4.80x10-7
6.00x10-7
-0.002
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018S
BD
, V
Time, sFigure 38.
Figure 39. -11.2
0n
-5.6
0n
0.0
0
5.6
0n
11.2
0n
16.8
0n
22.4
0n
28.0
0n
33.6
0n
39.2
0n
44.8
0n
50.4
0n
56.0
0n
61.6
0n
67.2
0n
0.000
0.007
0.014
SB
D, V
Time, s
Figure 40.
453.6
0n
459.2
0n
464.8
0n
470.4
0n
476.0
0n
481.6
0n
487.2
0n
492.8
0n
498.4
0n
504.0
0n
509.6
0n
515.2
0n
520.8
0n
526.4
0n
0.000
0.006
0.012
SB
D,
V
Time, s
20 bunch/train ATF DR injection The time separation between bunches in this case - 2.8 ns.
Small build-up
SBD speed performance measurements
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
3rd international school on Beam Dynamics
and Accelerator technology
to detector
movable
4(1 cos[ ])
total
sI I
l
For 1THz =0.3 mm l
2 ST
l
- period of cosines;
For good approximation ~20 experimental data point per autocorrelation period
will be needed, so for 1THz the mirror M5 should be moved with the step of
7.5m.
Michelson Interferometer
02 March 2021
The Michelson Interferometer is a
Fourier Transform Spectrometer
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Fourier Transform Spectrometer Interferogram
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Martin Puplett interferometer
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Bunch shape reconstruction Comparison of M-P-I and M-I
• Differential detection of two
polarizations gives better S/N
• Detected intensity is equal to input
intensity (past first polarizer) and
provides good input signal normalization
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Additional references General measurements of brightness and emittance
C. Lejeune and J. Aubert, “Emittance and Brightness, definitions and measurements”, Adv. Electron. Electron Phys.,Suppl. A 13, 159 (1980).
O. R. Sander, “Transverse Emiitance: Its Definition, Applications, and Measurements” in “Accelerator Instrumentation”, E. R. Beadle and V. J. Castillo, edts., (AIP CP212, 1991) pp. 127-155.
R. Becker and W. B. Herrmannsfeldt, “Why pi and why mrad”, Rev. Sci. Instrum. 77(2006).
A. Wu Chao, M. Tigner “Handbook of Accelerator Handbook of Accelerator Physics and Engineering Physics and Engineering” World Scientific
C. A. Brau “What Brightness means” in The Physics and Applications of High Brightness Electron Beam”, World Scientific, p.20
M. Reiser, “Theory and design of charged particle beams”, Wiley‐VCH
Shyh‐Yuan Lee, “Accelerator Physics”, World Scientific
J. Clarke “The Science and Technology of Undulators and Wiggles” Oxford Science Publications
H. Loos, “Diagnostic Systems for High Brightness Electron Injectors”, talk at 48thICFA Advanced Beam Dynamics Workshop on Future Light Sources, SLAC 2010
B.E.Carsten et al., ” Measuring emittance of nonthermalized electron beams
from photoinjectors” Nuclear Instruments and Methods in Physics Research A 331 (1993) 791-796
K.T. McDonald and D.P.Russel “Methods of emittance measurememnts”, Frontiers of Particle Beams Observation Diagnosis and Correction (1988), Volume: 08544, pp.1-12
M.P. Stockli “Measuring and Analyzing Transverse Emittances of Charged Particle Beams”, talk at BIW’06, Fermi National Accelerator Laboratory, Batavia, IL, May 1, 2006
C.P. Welsch “Low energy beam diagnostics developments within DITANET”, Proceedings of 2011 Particle Accelerator Conference, New York, NY, USA, MOP186
M. Minty, F. Zimmermann, “Measurement and control of charged particle beams”, Springer (2003)
Facilities:
P. Emma, A. Brachmann, D. Dowell, et al., “Beam brightness measurements in the LCLS Injector”, Compact X-RAY FELs using High-Brightness Beams, Aug.5-6, 2010, LBNL
A. H. Lumpkin et al. “High-brightness beam diagnostics for the APS linac”, Proceedings of the 1999 Particle Accelerator Conference, New York, 1999, pp.2134-2136
N.Terunuma “KEK ATF beam instrumentation program”, Proceedings of 2011 Particle Accelerator Conference, New York, NY, USA, WEODN2
J. Frisch et al.,“Beam measurements at LCLS”, BIW08, MOIOTIO02
R. Boni et al., “Activities on high brightness photo-injectors at the Frascati laboratories, Italy”, Proceedings of LINAC08, Victoria, BC, Canada, pp.618-620
X.J. Wang and I. Ben-Zvi, “High-Brightness Electron Beam Diagnostics at the ATF”,
Proceeding of BIW’96, AIP Conference Proceeding 390 (1996) 232-239.
Slit technique
A.Cianchi et al., “High brightness electron beam emittance evolution measurements in an rf photoinjector”, Physical Review Special Topics Accelerator and Beams 11, 032801, 2008
M.Ferrario et al., “Direct Measurement of the Double Emittance Minimum in the Beam Dynamics of the SPARC High-Brightness Photoinjector”, PRL 99, 234801 (2007)
D. Filippetto, “A robust algorithm for beam emittance and trace space evolution reconstruction” SPARC Note SPARC/EBD-07/002.
S. G. Anderson et al., ” Space-charge effects in high brightness electron beam emittance measurements”, PRST-AB, v 5, 014201 (2002)
R. Thurman-Keup et al., ” Transverse emittance and phase space program developed for use at the Fermilab A0 photoinjector”, Proceedings of 2011 Particle Accelerator Conference, New York, NY, USA, MOP226
S. Wojcicki, K.Friedel, „Systematical error of the measurement of electron beam emittance“,Vacuum, vol.51, Nr. 2, pp 113-118, 1998
M.P. Stockli et al., ”Self-consistent, unbiased exclusion methods of emittance analysis”, Proceedings of the 2003 Particle Accelerator Conference, pp.527-529
Multi –screen, quad technique
P. Castro, “Monte Carlo simulation of emittance measurements at TTF2”, DESY Technical Note 03‐03 , 2003 (21 pages)
C. Limborg et al., “A modified quadscan technique for emittance measurement of space charge dominated beams”, Proceedings of. PAC 2003, pp 2667 - 2669
Beam size measurements, screens, cameras
Mini Workshop on "Characterization of High Brightness Beams“, DESY Zeuthen 2008, (https://indico.desy.de/conferenceDisplay.py?confId=806)
A. Murokh et al., “Limitations on measuring a transverse profile of ultradense electron beams with scintillators”, Proceedings of the 2001 Particle Accelerator Conference, Chicago, pp.1333-1335
A. Murokh et al., Proceedings of the 2nd ICFA Advanced Accelerator Workshop, 564-580 (2000)
A.H. Lumpkin et al., Nucl. Instr. and Meth. A 429, 336-340 (1999)
S.Rimjaem et al., “Comparison of different radiators used to measure the transverse characteristics of low energy electron beams at PITZ”, DIPAC2011, TUPD54
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Additional references Tomography
A. C. Kak and Malcolm Slaney, Principles of Computerized Tomographic Imaging, IEEE Press, 1988.
D. Stratakis et al, “Tomography as a diagnostic tool for phase space mapping of intense particle beam”, PRSTAB, 9, 112801 (2006)
C. B. McKee, P. G. O'Shea, J. M. J. Madey, “Phase space tomography of relativistic electron beams”, NIM A, Volume 358, pp 264-267,
V. Yakimenko et al., “Electron beam phase-space measurement using a high-precision tomography technique”, PRSTAB, vol.6, 122801 (2003)
J. G. Power “SLIT SCATTERING EFFECTS IN A WELL ALIGNED PEPPER POT”, Proceedings of the 2003 Particle Accelerator Conference, pp.2432-2435
H. Zen et al., “Quantitative evaluation of transverse phase space tomography”, Proceedings of the 27th International Free Electron Laser Conference, pp. 592-594
Longitudinal diagnostic, RFD
T. Watanabe et al, “Overall comparison of subpicosecond electron beam diagnostics by the polychromator, the interferometer and the femtosecond streak camera”, NIMA, 480 (2002) 315–327
P. Emma, J. Frisch, P. Krejcik,”A Transverse RF Deflecting Structure for Bunch Length and Phase Space Diagnostics “, LCLS TN 00 12, 2000
D. Alesini, “RF deflector based sub ps beam diagnostics: application to FEL and advanced accelerators”, International Journal of Modern Physics A, 22, 3693 (2007)
C.P. Welsch “Development of longitudinal beam profile diagnostics within DITANET”, Proceedings of 2011 Particle Accelerator Conference, New York, NY, USA, MOP185
M. Hüning et al., “Observation of femtosecond bunch length using a transverse deflecting structure”, Proceedings of the 27th International Free Electron Laser Conference, pp.538-541
S. Zhang et al., “Temporal characterization of electron beam bunches with a fast streak camera at JLAB FEL facility”, Proceedings of the 27th International Free Electron Laser Conference, pp.640-642.
H.Loos et al., “Experimental studies of temporal electron beam shaping at the DUV-FEL accelerator”, Proceedings of the 27th International Free Electron Laser Conference, pp.632-634.
H.Loos, “Longitudinal diagnostics for short electron beam bunches”, SLAC-PUB-14120
S.J. Russel et al., ” Subpicosecond Electron Bunch Diagnostic”, LA-UR-2000-2135
Slice emittance
D. H. Dowell et al., ” Slice Emittance Measurements at the SLAC Gun Test Facility”, SLAC-PUB-9540, September 2002
M. Roehrs, et al., “Measurement of slice-emittance using transverse deflecting structure”, Proceedings of the 27th International Free Electron Laser Conference, pp.541-543.
I. Ben-Zvi et al. Picosecond-resolution slice emittance measurement of electron-bunches. In Proceedings of PAC1997, pp.1971-1973
1997.
Optical, laser techniques, EOS, laser wire
I.Wilke et al., “Single‐Shot electron beam bunch length measurements” PRL, v.88, 12 (2002)
G. Berden et al., “Electo‐Optic Technique with improved time resolution for real time, non destructive, single shot measurements of femtosecond electron bunch profiles, PRL v93, 11 (2004)
B. Steffen, “Electro‐optic time profile monitors for femtosecond electron bunches at the soft x-ray free electron laser FLASH“, PRSTAB, 12, 032802 (2009)
I. Agapov, G. A. Blair, M. Woodley, “Beam emittance measurement with laser wire scanners in the International Linear Collider beam delivery system”, PRSTAB, 10, 112801 (2007)
T. Shintake, “ Proposal of a nanometer beam size monitor for e+e linear collider”, NIM A311, (1992) p.453
M. Castellano, “A New Non Intercepting Beam size Diagnostics Using Diffraction Radiation from a Slit”, NIM A394, 275, (1997)
P. Karataev et al., “Beam-Size Measurement with Optical Diffraction Radiation at KEK Accelerator Test Facility”, Phys. Rev. Lett. 93, 244802 (2004)
E. Chiadroni, M. Castellano, A. Cianchi, K. Honkavaara, G. Kube, V. Merlo, F. Stella, “Non-intercepting electron beam transverse diagnostics with optical diffraction radiation at the DESY FLASH facility”, NIMB 266 (2008), pp.3789–3796
B.Steffen et al., “Spectral decoding electro-optic measurements for longitudinal bunch diagnostics at the DESY VUV-FEL”, Proceedings of the 27th International Free Electron Laser Conference, pp.549-551
N. H. Matlis et al., ” Electron bunch characterization using temporal electric-field cross-correlation”, Proceedings of 2011 Particle Accelerator Conference, New York, NY, USA, MOP229
D. Sütterlin, “Single-shot electron bunch length measurements using a spatial auto-correlation interferometer”, Proceedings of the 27th International Free Electron Laser Conference, pp.648-650
R. B. Fiorito, “Recent Advances in Beam Diagnostic Techniques”, Advanced Accelerator Concepts: Tenth Workshop. AIP Conference Proceedings, Volume 647, pp. 96-105 (2002).
J. Yang et al., “Spatial and temporal diagnostics of a high-brightness electron beam by technique of laser Thomson scattering”, Review Of Scientific Instruments, vol.73, Nr.4, April 2002
B. X. Yang and A. H. Lumpkin, “Simultaneous measurement of electron beam size and divergence with an undulator”, Proceedings of the 1999 Particle Accelerator Conference, New York, 1999, pp.2161-2163
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Summary
• High brightness electron beams require particular diagnostic for longitudinal and
transverse phase space characterization:
– Strong energy dependency (YAG for low energies, OTR – for high energies)
– Non-invasive techniques are highly desirable
– Slice parameters measurements are important
• Any accelerator (linear or circular) also requires core diagnostics:
– Monitor beam position (BPMs)
– Monitor beam charge (CTs)
– Monitor beam profile (Screens)
• Nowadays many Labs extensively using Coherent radiation, in this case they are:
– Choosing the most appropriate generation way (Radiation type).
– Measuring radiation intensity distribution (Detectors)
– … or even a bunch length (a few possibilities), which is usually related to the
radiation power spectrum (Interferometer , …)
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
Materials
• In this presentation I used materials from:
– Xavier Artru (LAL)
– John Byrd (ANL)
– M. Shevelev (TPU)
– A. Konkov (TPU)
– P. Karataev (RHUL)
– L. Bobb (RHUL, Diamond)
– U.S. Particle Accelerator School
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology
THANK YOU FOR YOUR
ATTENTION
02 March 2021 3rd international school on Beam Dynamics
and Accelerator technology