polarized Laser Compton Scattering gamma-rays National Institutes - - PowerPoint PPT Presentation
15th International Seminar on Electromagnetic Interactions of Nuclei (EMIN-2018), Moscow, 9 th Oct. 2018 Delbruck Scattering using linearly polarized Laser Compton Scattering gamma-rays National Institutes for Quantum and Radiological Science
15th International Seminar on Electromagnetic Interactions of Nuclei (EMIN-2018), Moscow, 9th Oct. 2018
Proposal of selective measurement of Delbruck scattering using linearly polarized laser Compton scattering beam
Generation of 1-MeV quasi-monochromatic gamma-ray for precise measurement of Delbrück scattering by laser Compton scattering H Zen, T Hayakawa, E Salehi, M Fujimoto, T Shizuma, J K Koga, T Kii, M Katoh and H Ohgaki, J. Phys. Coference series, 1067, 092003 (2018). Introduction: photon-photon interactions
Interactions between photon and photon
X-rays scattering using XFEL・SALCA
High energy new Vol.34 No.2 2015/07.08.09 in Japanese First measurement of photon-photon scattering. 5 TeV gamma-rays with uncertainty of 25% Only 13 events. ATLAS Collaboration, Nat. Phys. (2017). Pb-Pb heavy ion collision ATLAS Experiment using LHC 11 keV X-ray
The measurement of the gamma-ray energy after the target with the incident 450-MeV gamma-ray beam. Detector LCS gamma-rays Target Double Compton scattering made background events. Laser Electron
NASA X-ray energy spectra show two components. A candidate for lower component is photon splitting in strong magnetic fields. Candidate is a magnetar (neutron star with strong magnetic fields.)
X-ray pattern
The energy of scattered photon is almost identical to the incident photon energy.
Scattering of a photon by Coulomb field of nucleus
137
58, 2448 (1998).
Measurement using LCS gamma-ray in the energy range of 140-480 MeV
24Na(T1/2=15.02h)
150 mCi Scattering samples: Th and Bi (500g ) Ge: 76cc Many experiments were carried out using radioactivity and neutron capture gamma-rays at nuclear reactors with energies lower than 3 MeV.
There is the interference between several elastic scattering.
4 COHERENT CONTRIBUTIONS TO THE ELASTIC SCATTERING
Lowest order Feynman diagrams Higher order Feynman Diagrams
g g' x x e- e- e+ e+ x x g g' x x e- e- e+ e+ x x e- e+ x x Higher order (Za)2n n=2,3,4
lowest order (Za)2 Higher orders of Delbruck scattering proportional to Z^4, Z^6,,,,
Higher orders in gamma-ray energy has not been calculated.
Delbrück Rayleigh
Z = 92
HIgS (Duke Uni.) NewSUBARU
UVSOR-III
Differential cross sections depends
plane and the linear polarization plane. We search a specific condition at which we can observe selectively the amplitude of Delbruck scattering .
Detector LCS gamma-rays Linear polarization plane Target Scattered gamma-rays 70 degree
New code using the lowest
Present algorism package to calculate qucikly. An example of calculated results J.Koga, T.Hayakawa, IFSA 2013, proceedings. We found that the calculation can not be finished even if we use the supercomputer K.
・Nuclear Tomson scattering ・GDR Well known ・Rayleigh Second order s-matrix calculation
was retired around 2000. We got his code from him. ・Delbruck scattering De Tollis’s calculatioin
We use the formulae obtained by:
Negative ! Gamma-ray energy : 1.1 MeV Target： Tin
Angle Angle We found that the real part corresponding to virtual process has negative values lower than about 70 degree.
Cross sections If we use a linearly polarized gamma-rays as the incident beam, we can selectively measure the cross section of the Delbruck scattering at 70 degree. Proposed experiment
Detector LCS gamma-rays Linear polarization plane Target Scattered gamma-rays 70 degree
The minimum angle dose not depend on the energy of the incident photon.
http://www.eli-np.ro/
g 5103 /s /eV Eg =1.1 MeV DEg 510−3Eg 5.5keV 2.75107 /s
D = 0.8 D = 2(1−cos D 2 ) =1.510−4
Expected gamma-ray beam Detector detection angle EI-NP has constructed the next generation of highly intense laser Compton scattering gamma- ray source. We can obtain the cross section with statistical uncertainty of 1% with only 76 day measurement.
Real pair creation Virtual pair creation
Imaginary Part Real Part
Low energy High energy Virtual pair creation
PRL 22 (1969) 1008
HIgS in Duke University TERAS in AIST
Shutdown by the 2011 tohoku earthquake
1990’s ~
Compton scattering with FEL 2005年 ~
NewSUBARU in Spring-8 UVSOR-III in Okazaki ELI-NP high flux gamma-ray source
24
LCS gamma-ray generation with 2 um fiver laser H.Zen, et al. Energy Procedia 89 ( 2016 ) 335. Near future
1 GeV top-up mode operation + CO2 laser LCS gamma-ray energy is 1.7 MeV
1.7 MeV is table in low energy region
Not available
750 MeV top-up mode operation + CO2 laser LCS gamma-ray energy is just below 1 MeV
LCS γ-rays CO2 laseer BL1U beam line Detector UVSOR-III Energy: 750MeV Energy Spread: 5.3x10-4 Current： 300mA Bunch length: 128 ps Access Laser LASY20D Polarization : random
Beam diameter：2.4mm M2：below 1.2 Wave length：10.59 μm Inverse Compton scattering
500 1000 1500 0.0 0.5 1.0 1.5 2.0 2.5 3.0
w/o CO2 Laser with CO2 Laser
789 keV,
138La
Counts [#/keV/s] Gamma-ray Energy [keV]
138La 40K
500 1000 1500 200 400 600 Counts per Channel Energy [keV]
Measured spectrum with and without CO2 laser injection. The CO2 laser power was 1.1 W and the electron beam current was 1.3 mA. Difference spectrum which was calculated by subtracting the spectrum without the CO2 laser from the spectrum with the CO2 laser.
LaBr3(Ce) Scintillator 3.5”×4”
scattering from other elastic scattering.
found the specific conidian at which we can measure selectively Delbruck scattering.
H Zen, T Hayakawa, E Salehi, M Fujimoto, T Shizuma, J K Koga, T Kii, M Katoh and H Ohgaki, J. Phys. Coference series, 1067, 092003 (2018).