1. Investigation of the proton-induced reactions on natural molybdenum.
M. S. Uddin, M. Hagiwara, F. Tarkanyi1, F. Ditroi1 and M.Baba Cyclotron and Radioisotope Center, Tohoku University, Aramaki, Aoba-ku, Sendai , Japan. IInstitute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen, H-4001, Hungary.
Introduction

2. (Collaboration work between Tohoku University and Debrecen,Hungary)
CONTENTS
Introduction
Experimental
Data analysis
Results and discussion
Conclusion
(Collaboration work between Tohoku University and Debrecen,Hungary)

3. 1. Introduction 1.1 a) Activation of structural element
b) Importance of p-induced activation on molybdenum:
1. Thin layer activation,
2 a. Medical radioisotopes
i) 99mTc/99Mo, ii) 96Tc.
b. Reactions of 99Mo production
i) (n,) and (n, fission)
ii) 100Mo(p,pn)99Mo.
c) Radioactive wastes.

4. 1.2 Data status
1.3 Aim of the present work
Excitation functions
Thick target integral yield
22-70 MeV
AVF Cyclotron, Tohoku University.

5. 2. Experimental 2.1 Layout of Cyclotron and Radioisotope Center (CYRIC) Tohoku University

6. 2.2 Experimental specifications
Stacked-target technique
Proton source : AVF Cyclotron, CYRIC, Tohoku University
Proton energy : 70 MeV
Beam diameter: 0.8 cm
Beam current : ~25 nA
Irradiation time : 1 hr and 17 min
0.8 cm diam. Al Cu Mo
Proton Beam
70 MeV, ~25 nA
Monitor foil
Sample foil

7. 2.3 Experimental set-up HPGe-Gamma Detector HV+4000V Amp Al Cu Mo
Proton Beam
Monitor foil
Sample foil
HPGe-Gamma Detector
Radioactive material
Ge detector
HV+4000V
Gamma-ray
Amp
99mTc (140 keV)

8. 2.4 Proton energy degradationAl Cu Mo
Proton Beam
Simulation with SRIM
Monitor foil
Sample foil Al Cu
Energy Dispersion

9. Data analysis 3. Data Analysis 3.1 Formulae Reaction rate ……………(1)
 3.1 Formulae
Reaction rate
……………(1)
Cross-section
 = RNQ/(INdt) …………….(2)
Thick target integral yield
…………….(3)
Where
C = total counts of gamma ray peak area
 = decay constant (s-1) , ENSDF
 = efficiency, experimentally determined and coincidence- summing effect corrected.
 = branching ratio of gamma rays, ENSDF
N= number of atoms in the target Q= beam current (coulomb)
ti = irradiation time tc= cooling time
tm= counting time Nd= density, atom/cm3
I = beam flux , p/cm2/sec t = thickness, cm
N= number of atom dE/dt= stopping power
3. Data Analysis
Data analysis

10. 3.2 Monitor reactions Cu-monitor Al-monitor
3. natCu(p,x)56Co ( E= keV)
4. natCu(p,x)65Zn (E= keV)
5.natCu(p,x)62Zn (E= keV)
27Al(p,x)22Na (E= keV)
27Al(p,x)24Na (E= keV)
62Zn
65Zn
56Co

11. 3.3 Gamma lines separation
99Mo
99mTc
140 keV
99Mo(A1, 1)99mTc (A2, 2) 1.
(direct) 99mTc (A3, 3)
90Nb (A4, 4)
t=decay time 2.
2= 3

12. Theoretical calculations
4. Results and discussion
4.1 Excitation functions
Other experiments {
Comparison with
Theoretical calculations
100Mo(p,x)99Mo
natMo(p,x)93mMo
natMo(p,x)96Tc
natMo(p,x)95,95mTc

13. Excitation functions natMo(p,x)94Tc natMo(p,x)95Tc natMo(p,x)95mTc

14. Excitation functions
natMo(p,x)95Nb
natMo(p,x)90Nb
natMo(p,x)92m,96Nb

15. Excitation functions
natMo(p,x)86,88,89Zr
natMo(p,x)86,87,88Y

16. 4.2 Thick target integral yields

17. 5. Conclusion
5.1. Method:
The excitation functions of the proton-induced reactions on Mo were obtained by employing a stacked target technique in the energy range MeV.
We established a complete method to obtain reliable data of proton-induced reactions.
5.2. Results:
Obtained new data for all of the investigated radinuclides.
For 86Zr, 86,87,88Y radionuclides, the single curves of theoretical calculations do not fit our results because
i) the decay goes through a parent isotope and
ii) the model calculations are not reliable.
In most of the cases, the thick target integral yields are linearly rising with the increase of bombarding proton energy.
Yields of the radiocontaminants become large due to opening of several new reaction channels on natural Mo.

18. 5.3. Monitor:
Good agreement of the measured excitation functions of the monitor reactions to each other.
For 24Na and 62Zn radionuclides, the measured cross-sections are completely supporting recommendation data.
Measured cross-sections of 22Na production showed more consistent with recommendation in higher energy region than lower energy. Its production cross-sections became lower systematically than the recommended values with the decrease of proton energy.
Our measured values for 22Na will play important role to give proper recommended data.