A Synchrotron Radiation Facility to Supply
Ultraviolet Light, X-ray, MeV-photon, GeV-photon and Neutron
Presentation at APPEAL07 Workshop
Yoshitaka Kawashima
JASRI/SPring-8 Accelerator division
1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, JAPAN
1. Short review of a synchrotron radiation facility
We have proposed to improve a facility, the Booster synchrotron of SPring-8, to supply
ultraviolet photon, X-ray, MeV-photon, GeV-photon and neutron in 2002.
This proposal was not accepted.
Contributed persons to the proposal
(1) JASRI
T. Aoki, T. Asaka, Y.Asano, H. Ego, Y. Ohashi, Y. Kawashima, H. Saeki, S. Sasaki, K. Soutome,
S. Date, H. Tomizawa, M. Hara, K. Fukami, T. Magome, H. Matsui
(2) RCNP
T. Nakano, T. Hotta, M. Fujiwara
(3) Osaka University
A. Sakaguchi
(4) LNS, Tohoku University
K. Shimizu
http://www.spring8.or.jp/ja/support/download/publication/report_series/publicfolder_view
( written in Japanese )
2. Outline of an ideal synchrotron radiation facility
Proceedings of FLS2006,
Humburg, Germany,
WG112
Full energy injection
system
Schematic view of a facility
3.Quasi-monochromatic MeV-photon production
Production of MeV-photon
* The wagelength of laser light is fixed.
* Stored beam energy is variable.
CO2 laser : 10.6 µm
Incident angle : 0 degree
Electron
Obtained MeV-photon
Laser photon
E(photon) = 4"#
2
ε : laser photon energy
γ = Ee/ me, me: electron mass
Ee: electron energy
!
Monochromatic MeV-photon
distributes on the axis.
Cross section of Inverse Compton
photon
Electron beam
Scattering angle
CO2 laser
For example;
Expected monochromatic inverse Compton photons,
In case of SPring-8 storage ring ( using machine parameters)
CO2
: 1kW-CW,
Stored current
: 100mA
Interaction length : 10cm
Beam cross section :
Vertical size : < 10μ m
Horizontal size: 400μm
1mm2
Ee=2GeV
Total
MeV-photon ~109
Selection monochromatic
MeV-photon
Beam energy : 2GeV
Diameter: 2 mm
0.01 m radian
Resolution with collimator
"E
E
100m
Beam energy spread :
2"E
= 5.5 # 10
E
e
$4
e
("#$ ) = 2.2 % 10
2
x
2
2
2
1/ 2
@ 2 GeV
&2
!
The photon energy resolution
obtained by Compton scattering is
defined by beam divergence.
x
Com
e
&4
0.028%
!
Collimator
Beam divergence :
"E
2"E!
= {(
) +[(#"$ ) ] }
E
E
= {(5.5 % 10 ) + (2.2 % 10 ) }
Com
= ±0.14%
Com
e
!
Com
2
&2
1.1%
2
1/ 2
Selected MeV-photon at
2 GeV: ~108
4. Neutron production by using photon
How to produce neutrons ?
Fundamental idea was proposed by D.A. Gryaznykh et al.,
Nucle. Inst. and Methods. A448 (2000) 106-108.
Photoproduction reaction process:
9
Be(" # n) Be
8
Beryllium is chosen as
its photoproduction
cross section has three
peaks in the reagion
below 3 MeV.
!
How to produce a lot of MeV-photons?
Why use synchrotron radiation?
The most important merits:
(1) MeV-photon can be easily produced
(2) Low radioactive wastes
(3) Easy operation and maintenance
Super
conduction wiggler
Superconducting wiggler
e-
Demerit:
Low intensity
with hadron
process
comparing
interaction
MeV
photons
Electron storage ring
RF cavity : supplying energy to electron
MeV-photon spectrum from a superconducting wiggler
( Caluculation)
Stored beam energy : 8 GeV
Beam current
: 1 mA
Magnetic field
: 10 T
An apparatus for thermal neutron production
Neutron flux:
1.0 x105 cm-2 s-1
Conditions for simulation
(1) beam energy: 8 GeV
(2) stored current 100mA
(3) aperture : ±0.5mrad.
Be target size
15cm
2cm
20cm
Unit: cm
Simulation code : MCNUP
photon
Obtained neutron spectrum and comparison with other facilities
Nuclear reactors
KEK
booster synchrotron facility
Moderator of light water
in 2 cm thickness surrounded
by light water as a reflector
Moderator of light water
in 5 cm thickness
Radiation Protection Dosimetry (2005),
Vol.1. 115, No.1-4.pp.176-180
Is it possible to increase neutron flux ?
・increase stored current I ( I: stored current )linearly increasing
・increase magnetic field of SCW B linearly increasing
・increase stored electron energy
Ee4 ( Ee : electron energy)
5. Summary
(1) An ideal synchrotron radiation facility supplies
ultraviolet light,
X-ray,
MeV-photon (Monochromatic) ,
GeV-photon,
Neutron.
(2) Neutron
Photoproduction reaction process
Merit: easy operation and low radioactive wastes