STUDIES OF NUCLEAR-REACTIONS-IN-SOLID IN TITANIUM-DEUTERIDE UNDER ION BEAM IMPLANTATION -Experiments with deuteron beam implantation- Department of Nuclear Engineering Osaka University Shigeo Uneme
Introduction-1 Up to now, the chargedparticle spectrum, figure 1, which suggest multibody fusion have been observed, by implantation of deuteron beam to titanium deuteride (TiDx). We considered that the helium-3 and triton which had kinetic energy 4.75 MeV was emitted by 3D multi-body fusion. Counts/Channel 1.E+06 1.E+05 1.E+04 1.E+03 1.E+02 1.E+01 1.E+00 D-D triton Peak A (Proton) Pile up curve D-D 4.75MeV-Helium 4.75MeV-triton 0 1 2 3 4 5 6 7 8 9 Energy (MeV) D + 300keV D-D proton (pile up) 300keV 150keV Fig.1 Charged-particles spectra emitted from TiDx sample implanted with 300keV-deuteron beam a Range 2 m Active Zone TiDx
Introduction-2 Multi-body fusion branch 3D d d d 6 Li t(4.75mev) 3 He(4.75MeV) (1) d(15.9mev) 4 He(7.93MeV) (2) n p 4 He 20.1MeV (3) 4D d d d d 8 Be 4 He(12.8MeV) 4 He(12.8MeV)+ (22.2MeV) (4) 4 He(9.95MeV) 4 He(9.95MeV)+ (27.8MeV) (5) 4 He(5.75MeV) 4 He(5.75MeV)+ (36.3MeV) (6) 4 He(0.046MeV) 4 He(0.046MeV)+ (47.6MeV) (7)
Introduction-3 Active zone D + beam TiDx Metal atom Deuteron at Tetrahedral site Octahedral site Fig.2 : This figure is the image of multi-body fusion. It was reported that the multi-body fusion was enhanced by transitional condition which was induced beyond the range of incident beam
Experimental purpose D-D reaction prevent our detailed observing the spectrum which suggests the multi-body fusion. D + beam Multi-body fusion occurs beyond the range of incident beam. So, the kinetic factor is equal to zero, and the reaction emit chargedparticle at 180 degree symmetrically. Si-SSD TiDx sample While, the kinetic factor of D-D reaction is not equal to zero. So, the reaction do not emit chargedparticle at 180 degree symmetrically. Multi-body fusion D-D reaction Si-SSD 180 degree symmetric coincidence experiment can observe the detailed spectrum which suggests multi-body fusion.
Experimental System Deuteron beam Pre-Amp. Aperture φ 2mm L.Amp. L.Amp. Si-SSD at 120deg 450mm 2 Sample Ti foil thickness 5or20 m Si-SSD at 60deg 25mm 2 Liquefied nitrogen cooling MCA MMCA MCA A Thermocouple meter Fig.3:Schematic drawing of the experimental apparatus
Counts/Ch 1.E+06 1.E+05 1.E+04 1.E+03 1.E+02 1.E+01 12 C(d,p) 13 C D(d,t)P 16 O(d,p 0 ) 17 O 16 O(d,p 1 ) 17 O D(d,p)T D-D proton pile up 5.8MeV 10 B(d,p 1 ) 11 B 6.6MeV 10 B(d,p 0 ) 11 B 8.3MeV saturation? 10.5MeV 1.E+00 0 2 4 6 8 10 12 Energy(MeV) Fig.4:Charged-particle spectrum observed by 120 deg. Si-SSD emitted from Ti sample (thickness 5 m) implanted with 300keV deuteron beam (Target current 1 A) 1.E+06 1.E+05 1.E+04 D(d,t)P 12 C(d,p) 13 C D(d,p)T Counts/Ch 1.E+03 1.E+02 1.E+01 16 O(d,p 1 ) 17 O 16 O(d,p 0 ) 17 O D-D proton pile up peak A 6.1 MeV 1.E+00 0 2 4 6 8 10 12 Energy(MeV) Fig.5:Charged-particle spectrum observed by 120 deg. Si-SSD emitted from Ti sample (thickness 20 m) implanted with 300keV deuteron beam (Target current 10 A)
1 D-D proton chance coincidence 10 19 28 37 3D reaction t, 3 He 46 12 C(d,p) 13 C chance coincidence 55 64 73 82 Channel (120deg.) 91 100 3-4 2-3 1-2 0-1 109 118 S121 S113 S105 S97 S89 S81 S73 S65 S57 S49 S41 S33 S25 S17 S9 127S1 Channel (60deg.) Fig.6:This figure is the coincidence spectrum recorded MMCA.X-axis is the chargedparticle spectrum observed 120deg. Si-SSD.Y-axis is that observed 60deg. Si-SSD.
It was not a sufficient deuteron loading Why? The impurity reaction to D-D proton is much in comparison with the spectrum which is observed up to now. To rise the deuteron loading ratio, we did cooling target. Therefore it produced wide temperature gradient at cooling side and irradiation side, and proceeded the damage of a sample. or For the reason which is short of thickness of the sample, it did not create coherent in metal lattice. We considered that the reason that the spectrum which suggested multi-body fusion was not observed was short of thickness of sample. So, we paid attention to another branch. 3D 6 Li* d(15.9mev) + 4 He(7.9MeV) As for this coincidence experiment, a comparatively thick sample(500 m) can be used. At 60 degree Si-SSD:15.9MeV 5MeV
Experimental System Deuteron beam Pre-Amp. L.Amp. L.Amp. Si-SSD at 120deg 50mm 2 Aperture φ 7mm Sample TiDx (x=0.9 1.4) thickness 0.5mm Si-SSD at 60deg 25mm 2 Liquefied nitrogen cooling MCA MMCA MCA A Thermocouple meter Fig.7:Schematic drawing of the experimental apparatus
1.E+06 1.E+05 1.E+04 D-D triton 12 C(d,p) 13 C D-D proton D-D proton-triton pileup Counts/Ch 1.E+03 D-D proton pileup 1.E+02 14 N(d, 1 ) 12 C 1.E+01 1.E+00 0 1 2 3 4 5 6 7 8 9 10 Energy (MeV) 1.E+06 Fig.8:Charged-particle spectrum observed by 120 deg. Si-SSD emitted from TiDx sample (500 m thickness) implanted with 300keV deuteron beam 1.E+05 1.E+04 Counts/Ch 1.E+03 1.E+02 What is this? Spectrum A 3D-deuteron? Spectrum B 1.E+01 1.E+00 0 2 4 6 8 10 12 Energy (MeV)
S127 S118 S109 S100 3D-reaction d + 4 He S91 S82 S73 S64 S55 S46 S37 Channel (60deg. Si-SSD) Counts/Ch 3-5 1-3 -1-1 S28 S19 S10 S1 1 11 21 31 41 51 61 71 81 91 101 111 121 Channel (120deg. Si-SSD) Fig.10:This figure is the coincidence spectrum recorded MMCA.X-axis is the chargedparticle spectrum observed 120deg. Si-SSD.Y-axis is that observed 60deg. Si-SSD.
Spectrum A We tried to identify spectrum A. The metal foil which was Ti foil (50 m thickness) set front of 60deg. Si-SSD.If spectrum A is proton, spectrum A is had kinetic energy under 1MeV. 1.E+06 1.E+05 Counts/Ch 1.E+04 1.E+03 1.E+02 nothing Ti :50 m 1.E+01 1.E+00 0 2 4 6 8 10 12 Energy (MeV) Fig.11:Charged-particle spectra observed by 60deg. Si-SSD emitted from TiDx sample implnated with 300keV deuteron beam The kinetic energy of spectrum A is equal to all spectra. So, we considered that spectrum A was the neutron response.however, the yield of spectrum A which is recorded by nothing screening foil is much than that using titanium 50 m. Much of the spectrum A is occupied neutron response, but there is another charged-particle signal.
Spectrum B 1.E+06 Counts/Ch (nothing-ti:50 m) 1.E+05 1.E+04 1.E+03 1.E+02 1.E+01 1.E+00 0 2 4 6 8 10 12 Energy (MeV) Fig.12:This figure is counts difference between the counts of screening foil nothing and that of the Ti foil which is 50 m thickness. We consider that spectrum B suggests 3D multi-body fusion from Fig.12. But, there is the possibility that spectrum B is impurity reaction, because the neutron which reach to Si-SSD decrease by setting the metal foil in front of Si-SSD.
Conclusion The spectrum which suggests multi-body fusion is observed by 60 degree Si-SSD. We know that the most part of spectrum A is occupied neutron response by the experiments of using screening foil. But, the yield of using screening foil differ from that of no using. So, the possibility that the spectrum besides neutron response is observed suggests. spectrum B was not observed at coincidence measurement. But, it is observed by 60 degree Si-SSD. The possibility that it is the deuteron of multi-body fusion suggests. Future Work Another multi-body fusion branch (1) and the transition of 6 Li*(the virtual compound nucleus of 3D multi-body fusion) considered, we will verify the spectrum observed by 60 degree Si-SSD. 3D n + p + 4 He + 20.1MeV...(1) We will try the coincidence measurement adjusting solid angle. We will verify the impurity reaction expected occurring in Si-SSD