Measurement of activation cross section of (n, p) and (n, α) reactionsin the energy range of 3.5 to 5.9 MeV using a deuterium gas target
Masataka FURUTA 1,*, Itaru MIYAZAKI 1,Hiroshi YAMAMOTO 1, Michihiro SHIBATA 2, Kiyoshi KAWADE 1
1

Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Radioisotope Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.

2

Abstract

Activation cross sections of (n, p) and (n, α) reactions were measured by means of activation method in the neutron energy rangeof 3.5 to 5.9 MeV using a deuterium gas target. The irradiated target isotopes were 27Al, 28, 29Si, 41K, 51V, 61Ni, 65Cu, 64, 67Zn, 69Ga, 79Br,
92Mo and 93Nb. The values of the 29Si (n, p) 29Al, 67Zn (n, p) 67Cu, 69Ga (n, p) 69mZn, 79Br (n, p) 79mSe, and 69Ga (n, α) 66Cu reactions
were obtained for the first time. For the corrections of neutron irradiations, neutron spectra and mean neutron energies at the irradiation
positions were calculated. A systematics of the (n, p) reactions at the neutron energy of 5.0 MeV in the mass range between 27 and 92 were
proposed for the first time. The systematics can predict the cross sections within an accuracy of a factor of 1.6.

1. Introduction

4. Results

A lot of experimental cross section data have been reported in the neutronenergy of around 14 MeV. On the other hand, there are insufficient data around 5.0
MeV because there are few appropriate neutron sources for the measurement ofcross sections.
45Sc(p, n)45Ti

17Li(p, n)8Be

10100

D(d, n)3He

1 MeV

10131545KN-3750 Van de Graaff
Nagoya Univ.

67813

15

D2 GasLi( Incident particle : d+ )Ti-D

2. Experiment
Neutron irradiation facility : KN-3750 Van de Graaff at Nagoya Univ.
Accelerating voltage: 1-3.5 MV

Beam currents: ~ 1 µA

Neutron target: Deuterium gas target: ~ 2 106 cm-2.s-1

Neutron flux 115In(n, n')Cross section / mb

3(2) 28Si(n, p)28Al(3) 29Si(n, p)29Al(4) 41K(n, p)41Ar(5) 51V(n, p)51Ti(6) 61Ni(n, p)61Co(7) 65Cu(n, p)65Ni(8) 64Zn(n, p)64Cu(9) 67Zn(n, p)67Cu(10) 69Ga(n, p)69mZn(11) 79Br(n, p)79mSe(12) 92Mo(n, p)92mNb(13) 69Ga(n, α)66Cu(14) 93Nb(n, α)90mYT(d, n)4He

Neutron Energy
1 MeV 2

(1) 27Al(n, p)27Mg: Reaction was obtained for the first timed+ beamD2 gas target
Havar foil (thickness: 2.2 µm)

Pneumatic tube
Al ring(thickness:1 mm)
Polystyrene capsule (0.1 mmt)

Neutron energy / MeV

5. Systematics
The systematics of the (n, p) reaction
at a neutron energy of 5.0 MeVd+beam
Polystyrene foam
O ringD2 gas[ Solid line : even-odd, odd-even ]σn,p = 5.59 103(A1/3 + 1)2
exp{-1.30(Eth + Vp)}

SampleGas cell (Al)8mmφ x 29mml

Moniter foils (115In)[ Dotted line : even-even ]An expanded view around the gas target assembly. The target chamber consists of asmall cell made of aluminum and filled with D2 at 1.62 x 105 Pa. The samples were sandwiched
between two indium foils of 10 x 10 mm square and 0.2 mm thick, and were put in the samplecartridge. The indium foils of the 115In(n, n')115mIn reaction work as a neutron flux monitor.

σn,p = 1.38 107(A1/3 + 1)2
exp{-1.93(Eth + Vp)}
The relationship between σn,p/(A1/3 + 1)2and (Eth + Vp), where σn,p, A and (Eth + Vp)
are the cross section of the (n, p) reaction atan energy of 5.0 MeV, the mass number andsum of the threshold energy and the Coulomb
barrier, respectively.

3. Correction of background components
Relative Neutron Fluence10010-1Ecut-offΣ φ(Ei) . σ(Ei)Ecut-off0f = Emax

Σ0 φ(Ei) . σ(Ei)Main peak

10-2
10-3
10-40Emax

Ed = 3.0 MeV
12345Neutron energy / MeV

67

Calculated neutron spectra at 20 mm from the endof a cell of a deuterium gas target for primary deuteronenergy of 3.0 MeV. The Monte-Carlo simulation is used.
Ecut-off is neutron cut-off energy separating main peak andbackground components; Emax is maximum energy in theemission neutrons; φ(Ei) and σ(Ei) are neutron flux andcross section when emission neutron energy is Ei.

Magnitude of the correctionof background components
Reactionbackground / %27
11-71
Al (n, p)28
28-83
Si (n, p)29
24-52
Si (n, p)
41 (n, p)
12-42
K
51 (n, p)
23-75
V
61
19-54
Ni (n, p)
65
31-60
Cu (n, p)64
8-35
Zn (n, p)
67
14-37
Zn (n, p)
69
22-45
Ga (n, p)
79
10-33
Br (n, p)
92
18-50
Mo (n, p)
69
38-74
Ga (n, α)93
18-40
Nb (n, α)(a)115(n,n')
20-31
In(a) Standard reaction used in this work

6. Conclusion
We measured the cross section data of twelve (n, p) reactions andtwo (n, α) reactions in the neutron energy range of 3.5 to 5.9 MeV by using
the D2 gas target. The systematics of the (n, p) reaction at a neutron energyof 5.0MeV were proposed for the first time on the basis of our data withsimple parameters. It can predict cross sections of the (n, p) reaction within
accuracy of a factor of 1.6 in the mass range between 27 and 92.
References[1] T. Shimizu, H. Sakane, M. Shibata, K. Kawade, T. Nishitani, Ann. Nucl. Energy 31, 975 (2004).
[2] T. Shimizu, H. Sakane, M. Shibata, K. Kawade, T. Nishitani, Ann. Nucl. Energy 31, 1883 (2004).
[3] T. Shimizu, H. Sakane, S. Furuichi, M. Shibata, K. Kawade, H. Takeuchi, Nucl. Instr. Methods A527, 543 (2004)[4] T. Shimizu, I. Miyazaki, K. Arakita, M. Shibata, K. Kawade, J. Hori, T. Nishitani, Ann. Nucl. Energy 32, 949 (2005)[5] V. N. Manokhin, INDC(CCP)-398 (1996)[6] M. Furura, T. Shimizu, I. Miyazaki, M. Shibata, K. Kawade, Ann. Nucl. Energy, submitted.