BEAM DIAGNOSTICS AND
RADIATION DETECTIONSYSTEM
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.
e-mail: alar@post.kek.jp

高エネルギー加速器セミナーOHO’20,
8 – 11 September 2020

Outline• Introduction• Transverse Parameters Measurements– Beam position Monitors (BPMs)– Beam charge Monitors (current transformers - CTs)
– Wire scanners– Laser-wires– Beam profile Monitors (Screens)– EM radiation review– OTR/ODR• Longitudinal Parameters Measurements– RF deflector– Coherent radiation theory– Coherent Transition Radiation/Coherent Smith-Purcell Radiation– GHz/THz detectors– GHz/THz interferometers– Bunch shape reconstruction• Additional references• Summary
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General review• Accelerator performance depends critically on the ability tocarefully measure and control the properties of the accelerated
particle beams.
• This reflects in 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 futureaccelerators) 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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高エネルギー加速器セミナーOHO’20

Why it is a big deal?
• Good knowledge of accelerators, general physics andtechnologies 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.
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Typical linear accelerator beamline

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Diagnostic devices and beam properties
measured••••

Effect on beam:“N” – none“-” – negligible“+” – perturbing“D” – destructive• “” – primary purpose• “” – indirect use

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Diagnostic of High Brightness Electron
Beams
HB E-beam diagnostic
Bn I xn yn

General:•bunch charge
FC, ICT, Toroids•transverse position
 BPM: button, stripline,
cavity•arrival time (phase) BAM, RF pickups

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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Projected

Transverse

Transverse
profileProj.emittance,transv. phase
space

Slice

Longitudinal(temporal)
Energydistribution

Long.
phase
space

Current
profileSliceenergyspreadSliceemittanceTransverse Parameters Measurements
Usually the largest error in transverse parameters measurements is coming fromtransverse profile and rms size determination.
•

•

•

•
•

OTR monitors (~um Al or SUS foil)
Readout:– High energy (>tens of MeV)
•Zoom optics– No saturation•CCD camera– Resolution limit closed to optical diffraction limit (~10um)– COTR effects (especially for compressed bunches)• >12bit
Scintillator screens (e.g. YAG:CE, 100um)• l~ 1um..400nm– High photon yield• controllable iris
– Resolution  grain dimensions (~50um?) (powder / thin crystal)– Saturation (0.04pC/um^2?)•Insertable filters
Wire Scanner (good agreement with YAG measurements!)– Almost non-invasive– Higher beam power– Multi-shot measurements– 1D (projection perpendicular to the wire motion direction)– Rather complicated setup, long measurement time, background dependent
Diamond screen  long pulse train“Indirect” (SR – Optical Synchrotron Interferometry, Scattering, ODR, etc)
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Transverse Phase Space (Emittance)
Measurements
Emittance dominatedSpace charge
dominated
Slit mask techniques:• based onconversion of aspace charge
dominated beam into
emittance dominatedbeamlets

10 September 2020•Multi screen:•Based on linear beam matrix
approach•min 3 beam size measurements(at 3 positions) are needed forthe known elements of thetransport matrix (phase advance)•Quad(s) scan
•Beam size measurements as afunction of varied transport
matrix•Tomography•Related to Radon theorem: Ndim object reconstruction from M
projections in (N-1) dim space
高エネルギー加速器セミナーOHO’20• Systematic error from quadstrength determination(e.g hysteresis)• Thin lens model is notadequate• Large energy spread chromatic effects• Phase space distribution
assumed to be homogeneousSlit technique - general

Emittance
dominatedbeamlets

Multi slit mask = single shot measurement, but:
•Overlapping of beamlets when optimized for high resolution•Low sampling of the phase space
30
20

p

Space charge
dominated beam

x

10
0
-10
-20
-30
-2

x
-1

0

1

2

Transverse phase space reconstruction•Slit mask:• Opening: small enough• Thickness: thick enough to scatter beam, butalignment / angle acceptance•Distance L:•Long enough  divergence resolution•Not too long  signal-to-noise
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L nx  高エネルギー加速器セミナーOHO’20

x 2 x2  xx

2

Transverse projected emittance measurements at PITZ
beam at EMSY screen

Single slit scan techniquetransverse phase space> Emittance Measurement SYstem (EMSY) consistsof 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 (from4095=2^12-1); adjustment = gain X NoP> Image filtering (3sigma, bkg, x-ray, MOI)

2D scaled normalized RMS emittance

n 

x

x2



x 2  x2  xx

2

scale factor ( >1 ) introduced to correct for low
intensity losses from beamlet measurements

x - RMS beam size measured with YAG screen at
2.64 mObservation
screenEMSY1 (z = 5.74 m)

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slit location
SQRT(<x2>) - RMS beam size at slit location
estimated from slit positions and beamlet intensities
 “100% RMS emittance”

高エネルギー加速器セミナーOHO’20
pixel intensity

9月11日(金), 9:00~
空洞型ビームモニタ
本田 洋介

Beam Position Monitors (BPMs)• Used in high intensity machines with short bunches andSynchrotron light sources.
• The BPM consists of four metal buttons on the inside of theaccelerator structure, connected to wires that extend outside
the structure and are grounded.
• The entire apparatus is electrically isolated from theaccelerator structure itself.
• The information from the four buttons can be used tomeasure the number of electrons in the bunch anddetermine the position of the bunch.
• Buttons are used frequently in synchrotron light sources are avariant of the capacitive monitor.
• Picks up the wall currents at several positions• Huge dynamic range but poor resolution ~10um (typ.)
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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 wire (tungsten or carbon) moving across thetransverse section of the beam.
• Interception of the beam produces bremsstrahlung photons
and secondary emission electrons. Either  rays or secondary ecan be used for the information on beam profiles (Hor. & Ver.).
• The W.S. is attached to a precision mover with m resolution.
• 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 isdisplaced at 45 degrees to thehorizontal plane.
• In some cases, the  rays areconverted into pairs which create
Cherenkov Radiation in a
medium (ex. SLAC/FFTB).
• Minimum diameter size actuallyrealized is of 4 m, leading to aminimum 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-Perotcavity (low power laser) or without the cavity (high laser energy
per pulse)• The counting rates of scattered photons are measured as afunction 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-) aredirected 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 ScreensUVe-beam10 September 2020

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Luminescent screens• When a beam passes through aluminescent screen, part of thedeposited energy results in excitedelectrostatic states in the material
from which a light emission at adefined wavelength will follow.
• The light emission originates in
impurity inclusions, the so-called
activators, in most of the usedmaterials.
• They allow a direct observation of
the beam position and shape on a
TV monitor.
• They are necessarily single-passmonitors.
• Not very accurate
courtesy: Gérard Burtin (CERN).
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Beam Profile Monitors (Screens)
V.L. Ginzburg and I.M. Frank, Zh. Eksp. Teor. Fiz. 16 (1946) 15.

courtesy: H. Koziol (CERN).
•
•
•
•
•

Profile, rollPosition
ChargeEnergyEnergy spread

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For Bunch length or Bunch profile one have to take
into account transverse beam size.
高エネルギー加速器セミナーOHO’20

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.);)10 September 2020

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Polarization Radiation (PR)• Macroscopic treatment of PR began fromworks 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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高エネルギー加速器セミナーOHO’20

Transition Radiation• Transition radiation is created
when a charged particle crosses theinterface between two media ofdifferent optical properties.
• The radiation is emitted in two
directions:••

Forward: in direction of beam
propagation
Backward: in direction of specularreflection.

• 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 acomplex optical lines.
• Filters are needed to avoid saturating the camera.
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高エネルギー加速器セミナーOHO’20

Transition Radiation: possible measurements• Bunch length: due to the rapid formation of the radiation (~10E-13s), 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 theimage 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)


dW
e
sin    cos  sin2
 2 cos  

2
2
2
2
d d   c
(1


sin

cos

sin

)


cos

cos



2

2

  16

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2

Backward TR (vertical polarization)



dW
e
 cos  sin  sin2
 2 cos  

2
2
2
2
d d   c
(1


sin

cos

sin

)


cos

cos





2

2

  16

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2

Backward TR

dW
dW
dW 


d d  d d  d d   16

1.

2.

D.V. Karlovets and A.P. Potylitsyn, JETP Lett. 2009, Volume 90,
Number 5, Pages 326-331
D. V. Karlovets, JETP, 2011, Volume 113, Number 1, Pages 27-45

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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 thatcase, 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 (2GeV), 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

10 September 2020

OTR vertical polarization
component,
for sigma < ~15* um

高エネルギー加速器セミナーOHO’20

OTR image and Quadrupole scan.

Pavel Karataev, Alexander Aryshev, Stewart Boogert,
David Howell, Nobuhiro Terunuma, and Junji Urakawa
Phys. Rev. Lett. 107, 174801 – Published 17 October 2011
100um

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高エネルギー加速器セミナーOHO’20

FFTB Single Pulse Damage Coupon Test - front and back side - same scale
2 1010 8 x 6 m

Front

Back
Front

2 1010 8 x 6 m

Back

2 1010 9 x 8 m

Four pairs of
single pulse
damageholes front
and back

Front

Back

Front
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2 1010 9 x 11 m

BackDiffraction Radiation• Small recall:
As for Cherenkov Radiation and Transition Radiation, theDiffraction 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 theelectromagnetic field of the particle by the metal screen.

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高エネルギー加速器セミナーOHO’20

Diffraction Radiation: a simple approach• We can consider the DR as
resulting from the diffraction of
the virtual photon flux by theaperture (hole, slit, edge).
[Figure from Moran in NIMB]• The source of DR is a “disk” ofdiameter l/2. Consider a slit ofaperture a:* l<<2a =>DR radiation ~0* l>>2a =>DR similar to TR* l ~ 2a =>DR intensity<TR,
but enough for measurement

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Diffraction Radiation

Principle:
1. Electron bunch moves through ahigh precision co-planar slit in a
conducting screen (Si + Al coating).
2. Electric field of the electron bunchpolarizes atoms of the screen
surface.
3. DR is emitted in two directions:

DR Angular distribution

–

θy

–

e-

θ0

h

along the particle trajectory “Forward Diffraction
Radiation” (FDR)
In the direction of specular reflection “Backward
Diffraction Radiation” (BDR)

Impact parameter:
𝛾𝜆ℎ≤2𝜋Generally:
DR intensity ⇧ as slit size ⇩10 September 2020

高エネルギー加速器セミナーOHO’20

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 sometens 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 acceptanceDue 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.
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PVPC is obtained byintegrating over θx tocollect more photons.
高エネルギー加速器セミナーOHO’20

Visibility (Imin/Imax) of
the PVPC is sensitive tovertical beam size σy.

Diffraction Radiation measurements backgroundSource of background

Contribution

SR from beamline optics

High

Camera noise

E = 2.1 GeV
λ = 400 nm
a = 0.5 mm

Low

Residual background
SR + DR
interference

Use a mask upstream of target tosuppress SR contribution.
OTR

ODR
θy

SR
suppressione-θ0

P. Karataev et al., Proc. of EPAC 2004, THPLT067
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Mask

TargetSummary: comparison of different methods
Methods

Invasive ? Limit (m) Defined by

Intense beam

OTR (rms)

yes~5

CCD pixel size
+opticsno

OTR (PSF)

yes<1

CCD sensitivity +Optical background

no

ODR

no

~9

CCD pixel size
+optics

yes

Wire scanner

yes

~4

Wire diameter

noLaser wire(cavity)no<1

Laser (l) +Cavity modeyes

Laser-wire(high E)no<1

Laser (l) +transverse beam
quality, FF lensyes

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Bunch length measurements• Direct time-of-flight measurements– Streak camera (Profile reconstruction, Single Shot, Expensive, Spacecharge 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-11017.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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高エネルギー加速器セミナーOHO’20

Longitudinal Parameters Measurements
Temporal beam profile (bunch length) r(t)Time Domain

Radiator +Streakcamera

RFdeflector

Frequency Domain

Optical and laser techniques

Coherent radiations +Interferometer

Electro Optical Sampling = EOS

Transition = CTR
Diffraction = CDRIntercepting diagnostic•Radiators
Synchrotron CSR•OTR (Al foil)•Cherenkov (aerogel)
Smith-Parcell•Streak camera•T-resolution limited to 200...300 fs•Rather expensive
Cherenkov•Light collection \transport dispersion free beam line is•Interferometers (Michelson; Martin-Puplett)needed (reflective optic instead of•Spectrum acceptance is restricted  canlens)
impact the reconstructed beam profile•Guess distribution is needed
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•Non intercepting and not disturbing•Based on optical properties of anon-linear crystal interacting with
Coulomb field of e-beam

Laser Wire
•Non intercepting and not disturbing•Multi shot
•Complicated setupLongitudinal Parameters Measurements: RF deflector
Map time (longitudinal) axis onto transverse coordinate

RFD off
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
10 September 2020

RFD onOTR 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

高エネルギー加速器セミナーOHO’20

Longitudinal phase space measurements
Spectrometer dipole RFD (Energy scale from beam in spectrometer, time scale withtransverse deflector)

Imaging of longitudinal phase space with RF deflector

SPARC: 145MeV

LCLS: 135 MeVt
Fast single shot measurements
E
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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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Theory of Coherent radiationy

Radiative power of CSR emitted by a bunch of electronsPdPN  N  N  1  F  z , l dJ.S. Nodvick and D.S. Saxon, Phys. Rev., 96, (1954), 180
F  z , l   2 z z  exp i  2  dz  exp[ 4( z / l ) 2 ] exp2l
2 z2 2  z 
1

2

e2

o

b1

n

y

e1

x
r

x

Fourier transform of the electric field of a moving charge(so-called Lienard-Wiechert potentials for a moving charge)L      
 n n     



L
  R eE 4 2 0      2   exp i  t  c  dt0
 1  n     n  sin  x  cos  y , sin  y , cos  x  cos  y z    sin rL ,0, cos rL   R exp i 1    exp i    cos   i  sin   t 
 R  2L     2L  t  c   l  1  n    l  1  cos  y  cos  x  rL

10 September 2020e
b1  1,0,0



 

  
e1  e2  n

E Hor  E e 1

高エネルギー加速器セミナーOHO’20 
e2  b1  n EVer  E e 2-

Theory of Coherent radiationd 2 PVer2 4 EVerddd 2 PHor2 4 E Hor
dd

 x
2

 y





2

dP
d P
  
d x d yd Hordd
Hor x  y
2

 x
2

 y





2
dP
d 2P
  
d x d yd Ver x  y dd Ver

2

2

Coh
dPHor
dP
 Hor  N  N  N  1  F  z , l 
d
d

2

2

Coh
dPVer
dP
 Ver  N  N  N  1  F  z , l 
d
d

l2

Coh
Hor

P

 z    dPHor  N  N  N  1  F  z , l  22 dl
l1

d

l

l2

Coh
Ver

P
10 September 2020

 z    dPVer  N  N  N  1  F  z , l  22 dl
l1

d

l

高エネルギー加速器セミナーOHO’20

TR 3D Form-Factor
For a Gaussian bunch with transverse distribution

 ( x2  y 2 ) g ( x, y ) 
exp  2
22 r
2 r 
1and the longitudinal distribution

 z2 
1h( z ) 
exp   2 2 z 2 z 
the form factor for TR has view:2 2
 k z   
f (k )  exp     k r sin    


 
    where k– wave number, - observed
angle, -the velocityofelectronin the units of speedof light
10 September 2020
高エネルギー加速器セミナーOHO’20

Coherent radiation SpectrumdW || ( ) 

2



e
sin    cos  sin2cos
d d 


2
2
2
2
2
 c
 (1   sin  cos  sin )   cos  cos  
2

10 September 2020

2

高エネルギー加速器セミナーOHO’20

Smith – Purcell radiation
e

v
k

k

h



 Propagation of power Interference factor of the grating Structural factor of the gratingq = 2q0

0

d

10 September 2020aratio = daödæ1ln = ç - cosq ÷nèbø

高エネルギー加速器セミナーOHO’20

Smith – Purcell effect as resonant diffraction radiation, A.P. Potylitsyn, NIM B 145 (1998) 60 – 66.
2

d WRDRd d 

d 2Wsemiplaned d 

Fcell FN

Radiation distribution
Strip (cell)from a semiplane geometry factor22  
Fcell  4 exp  2    sinh   sin2  a / cos 0  sin  0
1   2 x2
l2  a / cos  0  
cos  0  
cos  y   0  


l



10 September 2020

高エネルギー加速器セミナーOHO’20

Interference
factor



new
0

0

 x  0;  y  20
Direction of the mirror
reflection from a strip.

Optimization of the strip tilt angle

θ x =0 deg;
θ y =90 deg;
γ=20;h=0.15 mm;
a=d=12 mm;
N=20

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高エネルギー加速器セミナーOHO’20

Pyroelectric detector

Golay cell detector

Rectifier-type detector

Bolometer

Time Constant (Not measured for each detector)~ 1 microsecond (depending on conditions of measurement)
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高エネルギー加速器セミナーOHO’20

Bolometer and Pyroelectric detectors

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高エネルギー加速器セミナーOHO’20

Golay cell and Diode detectors

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高エネルギー加速器セミナーOHO’20

Typical SBD oscilloscope trace
Radiation pulse duration is ~ 10 ps !!!

0.045

a

0.040
0.035
SBD, V

0.040

0.045

0.035

SBD, V

0.030

0.030
0.025
0.020

1 ns

0.015
0.010

0.005
0.000
-0.005

0.025

-2

-1

0.020

Injection
0.015

1-st turn0
Time, n s

1

2

2-nd turn

0.010
0.005
0.000

0.00
Figure 5a. Typical Oscilloscope traces of
the SBD signal for the ATF DR injection.
10 September 2020

460

920

Time, ns
高エネルギー加速器セミナーOHO’20

1380

0.018SBD speed performance measurements

0.016
0.014
0.012

SBD, V

0.010

Figure 40.

0.008
0.006
0.012

0.004

SBD, V

0.002
0.000-0.002-7-7

3.60x10-74.80x106.00x10

SBD, V

Time, s20 bunch/train ATF DR injection
The time separation between
bunches in this case - 2.8 ns.

0.007

0.000

Time, s67.20n61.60n56.00n50.40n44.80n39.20n33.60n28.00n22.40n16.80nFigure 39. 10 September 2020

11.20n

5.60n

0.00

-5.60n-11.20n

Small build-up
高エネルギー加速器セミナーOHO’20

526.40n520.80n515.20n509.60n504.00n498.40n492.80n487.20n481.60n453.60n0.014

476.00n0.000

Time, sFigure 38.

470.40n2.40x10464.80n-7

1.20x10459.20n

-7

0.00

0.006

Michelson Interferometer

movableto detector4 s
Itotal  I (1 cos[])lT

2  Sl - period of cosines;

For  1THz  l =0.3 mm
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
7.5m.
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高エネルギー加速器セミナーOHO’20

The Michelson Interferometer is a
Fourier Transform Spectrometer

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高エネルギー加速器セミナーOHO’20

Fourier Transform Spectrometer Interferogram

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高エネルギー加速器セミナーOHO’20

10 September 2020

高エネルギー加速器セミナーOHO’20

Martin Puplett interferometer

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高エネルギー加速器セミナーOHO’20

Bunch shape reconstruction
Comparison of M-P-I and M-I• Differential detection of twopolarizations gives better S/N• Detected intensity is equal to input
intensity (past first polarizer) andprovides good input signal normalization

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高エネルギー加速器セミナーOHO’20

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 ScientificJ. 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

10 September 2020

高エネルギー加速器セミナーOHO’20

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.640642.
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 emittanceD. 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

10 September 2020

高エネルギー加速器セミナーOHO’20

Summary•••

High brightness electron beams require particular diagnostic for longitudinal andtransverse 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 theradiation power spectrum (Interferometer , …)

10 September 2020

高エネルギー加速器セミナーOHO’20

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

10 September 2020

高エネルギー加速器セミナーOHO’20

THANK YOU FOR YOURATTENTION

10 September 2020

高エネルギー加速器セミナーOHO’20

Beam Position Monitors (BPMs)

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高エネルギー加速器セミナーOHO’20

Stripline BPM
•
•

•
•

•

•

Stripline has 4 strips running along theaxes of beam, parallel to the vacuum
chamber wall.
The length of the strip is usually longer
than the characteristic bunch lengthand equal to quarter wavelength offundamental RF.
The electromagnetic field of the beam
induces signal on the strip line.
The amplitude of signal is a functionof its solid angle subtended on the
beam and distance of the conductorfrom the beam.
Two ends of the stripline are taken outof the chamber. These are called
upstream and downstream ports
respectively with reference to the beam
direction.
Better resolution <10um

10 September 2020

Much better for a short bunches

高エネルギー加速器セミナーOHO’20

LUCX BPMs

10 September 2020

高エネルギー加速器セミナーOHO’20