LEPIT
Laser Electron Photon
Isotope Transmutation
via GDR by Medium-E photons
Hiro Ejiri
(S. Date T. Tajima)
RCNP Osaka &CTU Praha
1.Photonuclear reaction
via E1 GR
2. GDR energy and cross section
3. Transmutation rate
4. Reaction products
Photonuclear reactions via E1 giant resonance
Nuclear isotope transmutation/production
Isotopes production for
medical tracer & molecular biology
Isotope transmutation R&D for long-lived to
short lived nuclei for clean up
So far
Neutron reactions, only for specific isotopes with
large σ(cross sections)
Low E proton reactions, low yields thin targets
Nuclear spaｌlation, high intensity GeV protons. High cost
and extra wastes
Unique features of medium energy photons
1. Use coherent E1 giant resonance by medium E photons.
*Large and uniform cross section for all isotopes
∫σ(E1) dE = 280 α A fm2 MeV,
Small ΕΜ α~1/137 is compensated by A~100.
Note σ(n,γ) is used only in case of resonance E=0.
*Isotones of N-1 and N-2 by using
Eγ > E (γ,n) or E(γ, 2n) threshold energy
2. Realistic γ sources by laser electron scattering off GeV electrons.
3. Reaction products are effectivly used for others.
Neutrons and photons for isotope transmutation and science
Electron pairs for energy recovery and science.
E1 GR energy and photonuclear cross section
E1 GR energy MeV
Cross-section fm2
100
10
E MeV
σ fm2 = 0.01 b
B
C
1
10
100
Mass A
RI production rate and RI density
A. Production rate A=100 target with 20 gr /cm2,
B(n) = 0.5 branch, N(γ) = 2× 1011 /s/15-30 MeV,
σ(γ,n )~0.5 σ(GR) = 0.16 b,
N(Z,N-x) ~ 4×1010 /sec.
B. RI density
The photons are well defined into the target cylinder
θ = (m/E(e) )1/2 ~ 4×10-4 , r ~ 0.8 mm at 2 m
RI density 4×1010 /sec/0.4 gr
0.1 G Bq/mg ~ 100 M Bq/ml in case of 1 gr /cc.
Photon enrgy (MeV )
No of photons 10 9/sec)
Photon energy and intensity
B
C
100
10
1
0.1
0.1
1
Electron energy GeV
Using the HIGS value of N(γ) = 2×109 / sec
for 50 mA 0.624 GeV, E(l) = 1.6 eV (λ =780 nm),
N(γ) = 2× 1012 /sec / 500 mA for E(e)=1.2 GeV
RI’s by photonuclear reactions for PET.
Positron Emission Tomography
Isotope
Halflife m
Q(EC) keV
Reaction
Abundance %
11C
20.4
1982
12C
(g,n)
99
13N
10.0
2220
14N
(g,n)
99
15O
2.04
2754
16O
(g,n)
99
18F
109.8
1655
19F
(g,n)
100
Glucose (C6H12O6) FDG, where OH is exchanged by 18F, is introduced, and
positron annihillation photons are measured in coin. to identify the active point.
RI’s by photonuclear reactions for SPECT.
Single Photon Emission Computed Tomography
Isotope
Half life d
Eγ keV
Reaction
67Ga
3.26
93, 185
69Ga
99Mo, 99mTc
2.74 0.37
143
100Mo
111In
2.8
90, 94
126I
13
389, 666
201Tl
3.04
167
113In
127I
203Tl
(γ,n)
Abundance %
60
(γ,n)
9.6
(γ,2n)
4.3
(γ,n)
100
(γ,2n)
29.5
Nuclear and electron cross sections
Electron pair
1-2 γ’s 1-2 neutrons
Concluding remarks
1. Medium energy 20-30 MeV photons are used for isotope
transmutations of (Z,N) to (Z,N-1 and N-2) by (γ,n and
γ,2n) via coherent E1 GR.
2. The large cross section of σ ~ 0.3 πR2 for all nuclei, and
the large RI density of 0.1 G Bq/mg-ml make it realistic
to produce RI’s for molecular biology SN and PET.
3. Reaction byproducts of e-pairs, γ and n are used for
science as well as nuclear transmutation
4. It is of potential interest for transmutation of long-lives
to short lived isotopes in nuclear reactors.
Thank you for your attention
Thanks for your attention
View from Ejiri’s place at Yokohama