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Determination of coherent radiation spectra from interferograms. Gennady Naumenko Tomsk Polytechnic University. Contents. Traditional interferometers Michelson interferometers Martin-Puplett interferometers Divided wave front (DWF) interferometer . - PowerPoint PPT Presentation
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Determination of coherent radiation
spectra from interferograms
Gennady Naumenko
Tomsk Polytechnic University
Contents
• Traditional interferometers Michelson interferometers Martin-Puplett interferometers
• Divided wave front (DWF) interferometer. Measurements in Tomsk Polytechnic University Test in Shanghai Institute of Applied Physics • Possibility for spectral measurement on LUCX
Coherent synchrotron radiation spectra measurement on the FLASH beam
FLASH experimental conditions
• Single bunch charge: 0.6-0.9 nCb (4109e-)
• Single bunch length: 100 fsec
• Radiation energy from single bunch 50-100 nJ
• Lorenz-factor: 300
• A train consists of 1-100 single bunches
G. Naumenko, A. Potylitsyn, G. Kube, O. Grimm, V. Cha, Yu. Popov. NIM A 603 (2009) 35-37
DPU-1
Martin-Puplett interferometer of DESY TOSYLAB
The time characteristics of detector allow us to measure radiation from choosed separate bunch in train.
Detector DPU-1
(Tomsk Semi Conductive Devices Institute )
Low threshold diode Broadband
antenna
Spectrum reconstruction(Fourier transformation of interferogram)
DPU-1 Detector Sygnal Amplitudes
roof mirror position (mm)
79.0 79.5 80.0 80.5 81.0 81.5
det
ecto
r vo
ltag
e (V
)
0.00
0.01
0.02
0.03
0.04Sample of interferogram
of DESY TOSYLAB CSR beam
Lars Froehlich. DESY-THESIS 2005-011, FEL-THESIS 2005-02J
Divided wave front (DWF) interferometer. G. Naumenko, A. Potylitsyn, M. Shevelev, Yu. Popov, L. Sukhikh. Russian Physical Journal. 11 2 (2009) 254G. Naumenko, A. Potylitsyn, M. Shevelev , V. Soboleva, V. Bleko. IFOST-2012 proceedings (to be published)
R ad ia tio n
M o v ab le
Mir
rors
D e te c to r
F o cu s
R ad ia to rM o v ab le m irro r
D e te c to r
DWF interferometer for Tomsk microtron conditions
3 20mm
Sample from radiation source with wavelength 11.6 mm
Interferogram
Spectrum reconstructed
Mirror position (mm)
-100 -50 0 50 100
Rad
iati
on y
ield
(ar
b. u
n.)
0
500
1000
Wavelength (mm)
0 10 20 30 40
Ra
dia
tion
yie
ld (
arb
. u
n.)
0
10000
20000
30000
40000
The spectral resolution depends on the quality of plane and parabolic mirrors and on the aperture of detector. For this case the spectral resolution was
The spectrum reconstruction procedure is similar to the previous one.
6%
Sample of Tomsk microtron pseudo-photon spectrum
measurement
Mirror position (mm)
-100 -50 0 50 100
Rad
iati
on y
ield
(ar
b. u
n.)
0
500
1000
1500
2000
2500
3000
3500
Wavelength (mm)
0 10 20 30 40
Ra
dia
tion
yie
ld (
arb
. u
n.)
0
2e+4
4e+4
6e+4
8e+4
1e+5
B u n ch fie ld
E lectron b eam
Interferogram
Spectrum reconstructed
6.2
2.3
Electron energy MeV
Bunch length mm
Mirror position (mm)
-100 -50 0 50 100
Rad
iati
on y
ield
(ar
b. u
n.)
200
300
400
500
CChR spectrum measurement
Interfer
ometer
Interferogram
Spectrum
B e 20m h
Teflon target
CC
hR
Wavelength (mm)
0 10 20 30 40
Ra
dia
tion
yie
ld (
arb
. u
n.)
0
2000
4000
6000
8000
10000
12000
Test in Shanghai Institute of Applied Physics
20
0.19
Electron energy MeV
Bunch length mm
Zhang J.B., Shkitov D.A., Lu S.L., Shevelev M.V., Yu T.M., Potylitsyn A.P.,Ye K.R., Naumenko G.A., Deng H.X.
Proceedings IBIC-12 (to be published)
SPI-D Broadband Pyroelectric THz
Radiometer
DWF interferometer
or TR target
CTR spectrum measurement using Michelson interferometer
f (GHz)
0 100 200 300 400 500 600 700 800 900
Y D
ata
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Interferogram
Spectrum
f (GHz)
0 100 200 300 400 500
Yie
ld (
arb.
un.
)
0
2
4
6
8
10
12
14
16
Pseudo-photon spectrum measurement using DWF interferometer
Mirror position (mm)
55 60 65 70 75 80
Yie
ld (
arb.
un.
)
2.5
3.0
3.5
4.0
4.5Interferogram from DWF interferometer
SpectrumThe same scheme was used, but the mirror of Michelson interferometer was installed in the center of interferogram.
e-
Possibility for spectral measurement on LUCX
For bunch length= 10 ps we may have a coherent radiation in millimeter wavelength region. So the DWF interferometer with parameters used in Tomsk may be applicable for LUCX.
Michelson interferometerMin. Order: 1 SetFOB Price: US $3500/ Set
The DWF interferometer approximately two times cheaper. In addition, this interferometer provides the possibility to measure not only real photon spectra, but also the spectra of pseudo-
photons.