ISSN 10274510, Journal of Surface Investigation. Xray, Synchrotron and Neutron Techniques, 2013, Vol. 7, No. 2, pp. 239–247. © Pleiades Publishing, Ltd., 2013. Original Russian Text © R. Wisniewski, A.Yu. Didyk, T. WilczinskaKitowska, 2013, published in Poverkhnost’. Rentgenovskie, Sinkhrotronnye i Neitronnye Issledovaniya, 2013, No. 3, pp. 48–56.
Deuteron Disintegration, Thermonuclear and Nuclear Fission Reactions Induced by γQuanta in DSaturated Palladium and Dense Deuterium Gas with Synthesis of New Structures R. Wisniewskia, A. Yu. Didykb, and T. WilczinskaKitowskaa a
National Center of Nuclear Research, Otwock, 05400, Poland email: roland.wis
[email protected] b Joint Institute for Nuclear Research, Dubna, Russia email:
[email protected] Received July 20, 2012
Abstract—The results obtained by investigating the chemical composition and structure of Pd sample sur faces, chamber components, and a new synthesized object (NSO) are presented. The NSO is produced in the chamber with a highpressure (about 3 kbar) deuterium gas under irradiation by γquanta with an energy of 8.8 MeV. The measured concentrations of chemical elements arisen from nuclear reactions initiated by γquanta have made it possible to develop the phenomenological approach to describing the process whereby deuterium atoms are heated by the protons and neutrons of a deuteron photofission reaction, hot D–D fusion, Oppenheimer reactions, and palladium nuclear fission. The coefficient of the process efficiency greatly exceeds unity. A new type of reactors (deuterated nuclear fission reactor) is proposed. DOI: 10.1134/S1027451013020237
INTRODUCTION Since the middle of the last century, scientists have investigated processes proceeding in deuterium, tri tium, and helium (3Не) plasma to develop a thermo nuclear power reactor (TNPR) [1–3]. Despite the progress achieved, the problems of TNPR creation still remain unsolved although all processes occurring in it have been studied very well [1, 2]. In this study, we propose an alternative approach based on deuterium photofission reactions imple mented in a dense D gas and Dsaturated palladium under the action of γ quanta with the required energies. Each act of deuterium photofission leads to the genera tion of a neutron and a proton, and their energies are defined by the reaction kinematics and the correspond ing laws of energy and momentum conservation. The goal of this work is to examine the processes occurring in a dense D gas and Dsaturated palladium under the action of γ quanta with energies lower than the characteristic energy of giant dipole resonance (i.e., Еγ < 10 MeV) [4] and investigate the formation of new objects with different chemical compositions, which are generated during nuclear and chemical fusion reactions. EXPERIMENTAL To perform our experiment, a specialized deute rium highpressure chamber (DHPC) was designed and manufactured in several modifications.
A schematic diagram of the DHPC is presented in Fig. 1. The DHPC with an internal diameter of 0.4 cm contains the sample under study, which is a cylindrical 99.997%purePd rod 0.38 cm in diameter and 0.5 cm long. A 0.6cm manganin (Cu84Mn14Ni2) foil was used to separate the palladium rod and a brass screw (brass substrate) 0.5 cm long and 0.5 cm in diameter, which was intended to accumulate the objects synthe sized due to nuclear and chemical reactions in the DHPC. This foil isolated the Pd rod from the brass screw and simultaneously restricted the flux of parti cles or atomic clusters that had to escape from the Pd rod during its intense heating. The DHPC internal volume was VD = 0.264 cm3 and was filled with molec ular deuterium at a pressure of about 3 kbar. In this case, the molecular deuterium density was nD = 2.593 × 1022 D2 molecule/cm3 [5]. Thus, the total number of deuterium atoms was ND = 1.369 × 1022. The experimental study into the effects of irradiation by γ quanta with a continuous spectrum and the limit ing energy Еγ < 8.8 MeV was performed using an elec tron accelerator with the electron energy Ее = 9.3 MeV. Figure 2 depicts the cross section of the deuteron photofission reaction d(γ, n)p [4, 6] and two γquan tum spectra, which were obtained at threshold ener gies Еγ less than 8.8 and 23 MeV, versus the energy per 1µA of the electronbeam current.
239
WISNIEWSKI et al.
240 1
2
3
4
5
6
7
8
9
10
11
12
13
14
Fig. 1. Schematic representation of a DHPC: (1) ionizing particles (γ quanta), (2) atheclosing screw with an inlet hole, (3) the reinforcing shell of the highpressure chamber, (4) Cu0.98Be0.02 input window, (5) highpressure seals, (6) Cu0.98Be0.02 walls of the highpressure chamber, (7) deuterium, (8) the brass foil, (9) the Pd rod, (10) the separating manganin foil, (11) the synthe sized reaction product, (12) the brass screw, (13) the highpressure capillary, and (14) the valve with a tensorgage pressure sensor.
2.0
Nγ(Eγ < 23 MeV) 1014
1.5 1.0 0.5 0
1013 Nγ(Eγ < 9 MeV)
1012
ΔW 5 10 15 20 γquantum energy, MeV
Fig. 2. Deuteron photofission cross section σ[d(γ, n)p] and two γquantum spectra Nγ(Еγ), which were obtained at threshold energies Еγ less than 9 and 23 MeV, versus the energy per 1µA of the electronbeam current.
ing energies of 8.8 and 23 MeV in the photofission reaction d(γ, n)р, using the expression E γmax
(
max
Y Eγ
) = βN ∫ D
σ d(γ,n) p(E γ )N γ (E γ )dE γ,
(1)
ΔW
where the deuteron binding energy is ΔW = 2.22 MeV. Figure 3 presents histograms with the number of neutrons and protons (at a step of 0.5 MeV) and the total numbers of neutrons and protons at γquantum energies of 8.8 and 23 MeV, respectively, and an elec tron current of 1 µA. In our experiment with the DHPC irradiated by γ quanta, the irradiation time was t = 2.22 × 104 s (approximately six hours) while the electronbeam
Number of n and p in the energy range of 1 MeV
2.5
Nγ(Eγ), (MeV sr–1)
Deuteron photofission cross section, mbarn
The γquantum spectra Nγ(Еγ) were calculated from the expressions reported in [7]. The total γquan tum flux entering into the DHPC internal volume with the Pd rod inserted is estimated by introducing the coefficient β, whereby the measurement units of the γquantum energy spectra are converted from (mega electronvolt)–1 (steradian)–1 to units of γquantum flux density per unit area. In calculations, the coeffi cient β was chosen from experimental data under assumption of the maximally possible losses of γ quanta. Its value was β ≈ 0.026. Let us now calculate the flux of neutrons and protons with energies up to (0.5[E γmax – ΔW]) at the energy intervals ΔEγ = 1.0 MeV, which was generated by γ quanta with limit
0 < Eγ < 23.0 MeV
107
Np = Nn = 9.1 × 107
106
Np = Nn = 1.5 × 106
105
0 < Eγ < 8.8 MeV 0
5 10 15 Energy range En + Ep, MeV
20
Fig. 3. Histograms with the number of neutrons and pro tons from the reaction d(γ, n)p at the threshold γquantum max
energies E γ
= 8.8 and 23 MeV, respectively.
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
DEUTERON DISINTEGRATION, THERMONUCLEAR AND NUCLEAR FISSION REACTIONS
(a)
1 mm
(b)
241
100 μm
Fig. 4. (a) Optical photograph and (b) SEM image of the NSO.
current to a braking W target was about 7 µA on the average. The total number of neutrons and protons produced experimentally by exposure to γ quanta was Nnp= 3.23 × 1010. It should be emphasized that the action of γ quanta was accompanied by cooling of the DHPC in air. The temperature of the compressed air flows was Т = 20°С. However, the temperature of the DHPC external surface exceeded 100°С Before opening the DHPC, the internal pressure was measured and turned out to be ~3 kbar. Since the induced activity of the irradiated chamber was high, its opening was carried out within approximately six months of completion of the irradiation process. Thereafter, it was found that the Pl rod with an exter nal diameter of 3.8 mm was jammed because its diam eter increased and reached the internal size of the brass foil 4 mm in diameter (Fig. 1, position 8). Two days later, the palladium rod decreased in size presumably because of deuterium desorption and detached spon taneously. As was expected (which in fact is clear from the schematic diagram of the DHPC), a new synthe sized object (NSO) was detected on the surface of the brass screw (Fig. 1, positions 11, 12). The NSO resem bled a volcano with a central crater, was bright blue, and had dielectric properties (Figs. 4a, 4b). Hence, to perform further investigations via scanning electron microscopy (SEM), a gold layer about 1000 Å thick was deposited onto its surface. RESULTS OF INVESTIGATION INTO THE INTERNAL SURFACES AND CHEMICAL COMPOSITION OF ALL ELEMENTS IN THE DHPC CHAMBER VIA SEM AND XRSMA It is important to note that Xray spectrum microanalysis (XRSMA) and SEM of the surfaces of all samples were carried out at three independent research centers by means of different scanning elec
tron microscopes with Xray probe analysis and via Xray diffraction analysis. This made it possible to obtain true data on changes in the structure and chem ical composition of all DHPC surfaces and its compo nents after irradiation by γquanta. As is seen in Figs. 4a (an optical photograph) and 4b (an SEM image), the NSO looks like a volcanic crater with smooth walls, especially in the central region. The NSO top contains patches in the shape of solidified droplets, different structures are observed on the volcaniccrater bottom, and solidified drips of a blue molten material are located on the brass substrate. External examination indicates that the brasssubstrate surface seems to be unchanged. However, the same cannot be said about its chemical composition. XRSMA have revealed the following concentra tions of chemical elements (at %) on the upper edge of the crater wall of the NSO (Fig. 1, position 11): 40.24 6C, 42.87 8O, 0.65 11Na, 1.40 12Mg, 3.49 13Al, 3.71 14Si, 0.75 19K, 5.26 22Ti, 0.44 29Cu, 0.26 30Zn, and 0.94 79Au. It is especially pertinent to note the high con tents of Ti (13.07 wt %), Al (4.88 wt %), Si (5.41 wt %), and Mg (1.77 wt %) and the very small amounts of basic elements underlying the brass screw, namely, Cu (1.44 wt %) and Zn (0.87 wt %), that were observed in the measured region of the crater top. XRSMA data provide the following concentrations of chemical elements (at %) on the brass screw surface around the NSO (Fig. 1, position 12): 39.70 6C, 0.86 8O, 0.25 26Fe, 29.29 29Cu, 18.40 30Zn, and 1.49 41Nb. In the region of the ''lava'' spread from the NSO walls (Fig. 4a), the sample surface has the following concentrations of chemical elements (at %): 55.01 6C, 35.08 8O, 1.48 12Mg, 0.92 13Al, 2.26 14Si, 0.35 19K, 2.47 22Ti, 0.85 29Cu, 0.49 30Zn, and 1.10 79Au. All elements observed on the flat top of the volca nic crater (in the central part of the object) were also revealed on the molten patch of the socalled lava (although in somewhat different amounts): Ti
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
WISNIEWSKI et al.
242
Point 8
(a)
3 μm
(b)
10 μm
Fig. 5. Different types of objects detected on the crater bottom: (a) platelike and (b) recrystallized structures and almost spherical Pd droplets.
(4.44 wt %), Al (1.04 wt %), Si (2.65 wt %), and Mg (1.77 wt %). In this case, the contents of copper and zinc forming the basis of the brass screw were higher: 2.26 and 1.32 wt %, respectively. This can be explained by the fact that the spread layer is thin and an electron beam partially penetrates up to the brass substrate dur ing analysis. It is important to note that the NSO oxygen con centration is very high (42.87 and 35.08 at % in the crater walls and spread lava, respectively). At the same time, the oxygen concentration on the brassscrew surface is no more than 0.86 at %. According to the results of Xray diffraction analysis, the NSO contains Ti in the form of rutile, i.e., titanium dioxide (TiO2), which probably appeared due to the interaction between Ti and oxygen liberated in the nuclear reac tions. Figure 5 illustrates two types of objects revealed on the crater bottom: platelike (Fig. 5a) and recrystallized (Fig. 5b) structures. Bright dots are spherical droplets consisting predominantly of palladium. It is of interest to consider the chemical composi tions of objects on the crater bottom, such as recrystal lized structures, numerous thin flat plates of different shapes, and small fused Pd clusters. It is worthy to note that all these objects are weakly attached to the crater bottom because they move under the action of heating caused by an electron beam. The flat plates located on the crater bottom have the following chemicalele ment composition of (at %): 19.57 6C, 20.29 8O, 3.98 19K, 50.65 22Ti (the content of 22Ti is 66.42 wt %), 0.77 26Fe, 2.11 29Cu, 1.42 30Zn, and 1.22 79Au. It should be emphasized that the chemical composition of the crater bottom is identical to that of platelike objects. As can be seen, the platelike objects include a large amount of 22Ti (up to 66.42 ± 0.97 wt %). In addition, Xray diffraction analysis has demonstrated that Ti is included as rutile (TiO2). It is also necessary to note that, together with Ti (its content is dominant), the platelike structures were found to include elements with close atomic numbers (nuclear charges), such as 19K (4.26 ± 0.16 wt %) and 26Fe (1.17 ± 0.07 wt %), and small concentrations of 29Cu (3.68 ± 0.12 wt %)
and 30Zn (2.54 ± 0.10 wt %). As is clear from the fore going, the concentrations of Cu and Zn are almost identical in the platelike objects and the upper part of the NSO crater and approximately equal to those in the alloy on the brass screw surface. The analyzed surface of the other object recrystal lized on the crater bottom (Fig. 5b) has the following elemental composition (at %): 20.87 6C, 8.80 8O, 3.31 13Al, 2.76 22Ti, 1.35 26Fe, 35.56 29Cu, 21.36 30Zn, and 2.85 79Au. The elemental composition of the brass substrate near the synthesized object (Fig. 1, position 12) was studied repeatedly and more comprehensively with the help of another scanning electron microscope. The following elemental compositions (wt %) were established at four measuring points on the NSO top: Point 1: 26.81 6C, 37.78 8O, 0.44 12Mg, 5.27 13Al, 6.88 14Si, 1.7 19K, 0.3120Ca, 13.17 22Ti, 0.31 26Fe, 1.17 29Cu, 0.67 30Zn, and 5.39 79Au. Point 2: 50.5 6C, 38.43 8O, 1.62 12Mg, 2.92 14Si, 0.32 22Ti, 0.81 30Zn, and 5.39 79Au. Point 3: 38.51 6C, 26.35 8O, 0.74 12Mg, 4.81 13Al, 7.36 14Si, 0.27 17Cl, 1.76 19K, 9.73 22Ti, 0.7 29Cu, 0.83 30Zn, and 8.93 79Au. Point 4: 56.69 6C, 30.39 8O, 1.7 12Mg, 0.89 13Al, 4.03 14Si, 0.28 19K, 2.54 22Ti, 0.67 30Zn, and 2.81 79Au. Note that high concentrations of Ti Ti (13.17 and 9.73 wt %), which are accompanied by the presence of associated chemical elements, such as 13Al (5.27 and 4.81 wt %), 14Si (6.88 and 7.36 wt %), and 19K (1.7 and 1.76 wt %), and 26Fe, 20Ca, 17Cl, and 12Mg are observed at two measuring points. The elemental compositions of the brassscrew surface were measured at six points on one side of the solidified lava from the crater near the NSO and at four points on the other side. The following elemental compositions (wt %) were measured at the six points. Point 1: 40.21 6C, 25.79 8O, 1.58 12Mg, 0.33 13Al, 3.46 14Si, 0.87 19K, 0.26 20Ca, 12.88 22Ti, 0.46 26Fe, 3.6 29Cu, 2.49 30Zn, 0.99 46Pd and 7.07 79Au. The ratio between Cu and Zn is 1.45.
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
DEUTERON DISINTEGRATION, THERMONUCLEAR AND NUCLEAR FISSION REACTIONS
243
Spectrum 1 Spectrum 3 Spectrum 2
Spectrum 1
Spectrum 2
(a)
60 μm
(b)
100 μm
Fig. 6. SEM images of the (a) initial and (b) irradiated surfaces of the Pd rod.
Point 2: 28.73 6C, 2.47 8O, 0.12 17Cl, 0.19 26Fe, 38.84 29Cu, 25.45 30Zn, and 4.21 79Au. The Cu/Zn ratio is 1.53. Point 3: 31.79 6C, 1.12 8O, 0.25 26Fe, 41.59 29Cu, 24.76 30Zn, and 0.48 79Au. The Cu/Zn ratio is 1.68. Point 4: 49.81 6C, 7.43 8O, 0.73 11Na, 0.37 13Al, 0.0 14Si, 0.45 17Cl, 0.17 20Ca, 0.28 22Ti, 0.86 26Fe, 21.45 29Cu, 12.98 30Zn, and 5.47 79Au. The Cu/Zn ratio is 1.65. Point 5: 33.16 6C, 1.12 8O, 0.17 13Al, 0.13 14Si, 0.26 20Ca, 0.2 26Fe, 39.97 29Cu, 23.29 30Zn, and 0.7 79Au. The Cu/Zn ratio is 1.72. Point 6: 39.78 6C, 6.16 8O, 1.06 13Al, 0.86 14Si, 0.26 20Ca, 0.12 22Ti, 0.15 26Fe, 29.74 29Cu, 17.39 30Zn, and 4.72 79Au. The Cu/Zn ratio is 1.71. It follows from the foregoing that the ratio between the copper and zinc concentrations increases almost regularly when the edge of the brass screw is approached. This directly confirms that the brass screw surface is covered (and the NSO itself is formed) by nuclear reaction products from the overheated Pd rod, which evidently ejected not only atoms and atomic clusters but also Pd and Ti fragments (Fig. 5). As in previous measurements, the oxygen concentra tion on the brass surface is small and remains large in the melt near and inside the NSO. Let us investigate all surfaces and chemical compo sition of the palladium sample. SEM images of the ini tial and modified surfaces of the irradiated Pd rod, which were obtained at the rod edge adjacent to the NSO, are presented in Figs. 6a and 6b, respectively. The edge of the Pd rod (Fig. 1, position 9) has the following elemental compositions (wt %) at seven measuring points: Point 1: 3.05 8O, 49.25 29Cu, 37.99 30Zn, and 1.51 46Pd. The Cu/Zn ratio is 1.23. Point 2: 12.55 29Cu, 5.92 30Zn, and 74.26 46Pd. The Cu/Zn ratio is 2.12. Point 3: 14.64 8O, 0.65 14Si, 1.08 16S, 0.71 20Ca, 1.38 22Ti, 8.29 29Cu, 3.81 30Zn, and 25.66 46Pd The Cu/Zn ratio is 2.18.
Point 4: 6.45 29Cu, 3.02 30Zn, and 88.18 46Pd. The Cu/Zn ratio is 2.14. Point 5: 3.88 29Cu, 2.55 30Zn, and 93.58 46Pd. The Cu/Zn ratio is 1.52. Point 6: 22.76 8O, 3.37 13Al, 3.4 14Si, 0.54 19K, 11.61 22Ti, 31.20 29Cu, 10.41 30Zn, and 10.71 46Pd. The Cu/Zn ratio is 3.0. Point 7: 2.89 8O, 0.38 12Mg, 28.73 29Cu, 7.59 30Zn, and 52.49 46Pd. The Cu/Zn ratio is 3.79. The end of the Pd sample facing the NSO was con verted into an inhomogeneous rod consisting of sepa rate clusters with different chemical compositions. Its thickness and diameter were 82 µm and 3.8 mm, respectively. Hence, when the DHPC was opened, the Pd rod could not be retrieved because its volume increased appreciably. It is obvious that, during palla dium disintegration, such an inhomogeneous struc ture of the rod end was formed as a result of generating Cu and Zn with concentrations of 31.20 and 10.41 wt % at point 6 and 49.25 and 37.99 wt % at point 1. At the same time, the Ti concentration reaches 1.38 (point 3) and even in some places 11.61 wt % (point 6). The concentrations of the associated chemical elements are 0.65 (Si), 1.08 (S), and 0.71 (Ca) wt % at point 3 and 3.37 (Al) 3.4 (Si), and 0.54 (K) wt % at point 6. It is necessary to note that intense processes of evaporation of both atoms and their clusters were observed upon strong heating of the palladium surface, which occurred randomly in separate regions charac terized by the spontaneous reactions of light nuclei fusion and Pd nuclei fission. The mentioned clusters involved lighter atoms that were ejected together with larger pieces of palladium and remelted copper–zinc alloys and which reached the crater bottom (Fig. 5). This is entirely confirmed by the fact that the Cu/Zn ratios differ from two (at several points) to approxi mately four. In addition, atoms, atomic clusters, and even pieces were thrown out toward the surface of the input window in the DHPC (Fig. 1, position 4).
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
WISNIEWSKI et al.
244
Spectrum 2
Spectrum 2 Spectrum 1
Spectrum 3
Spectrum 1 Spectrum 3
(a)
300 μm
(b)
60 μm
Fig. 7. SEM images of the central part of the input window made of beryllium bronze: (a) low magnification and (b) 5X magni fication.
The elemental compositions (wt %) of the rod end facing the input window (Fig. 1, position 4), measured at three points, have the following values: Point 1: 5.78 6C and 94.22 46Pd. Point 2: 4.19 6C, 3.0 8O, and 92.81 46Pd. Point 3: 5.84 8O, 1.93 23V, 4.88 24Cr, 72.44 26Fe, and 14.92 74W. The Xray lines of oxygen and carbon resemble those of palladium. Hence, it can be assumed that the elemental compositions correspond to the initial highly pure palladium at points 1 and 2. The initial palladium (points 1 and 2) and the irradiated lateral surface (points 3 and 4) have the following elemental compositions: Point 1: 100 46Pd. Point 2: 5.81 8O, and 95.19 46Pd. Point 3: 11.14 8O, 0.33 13Al, 0.72 14Si, 1.03 16S, 0.58 19K, 1.00 20Ca, 4.07 26Fe, 22.85 31Ga(78Pt), 8.84 42Ru, 31.18 46Pd, and 18.27 57La. Point 4: 16.68 8O, 0.57 11Na, 0.9 13Al, 1.61 14Si, 0.37 15P, 1.0816S, 1.66 17Cl, 1.53 19K, 1.13 20Ca, and 74.47 46Pd. It is obvious that both the second end and lateral surface of the Pd rod underwent dramatic changes. The lateral surface of the Pd rod changed drastically, and the sample itself became darker than the initial one. Moreover, the lateral surface became more inho mogeneous and acquired many cracks, and its contrast was darker than on the surface patches with high pal ladium concentrations. Some of the aforementioned elements (23V, 24Cr, and 26Fe) were detected in the crack at the opposite edge of the Pdrod end, and 19K, 20Ca, 26Fe, 42Ru, and 43Rh + 79Pt with concentrations of several weight percent were observed in the cracks on the lateral surface of the Pd rod. Below, it is demonstrated that the formation of impurities implies nuclear reactions that proceed in palladium saturated with deuterium. According to these reactions, heavy 46Pd nuclei split into two lighter fragments, e.g., 22Ti and 24Cr and associated elements in decay chains: 19K, 20Ca, and 26Fe.
In addition, attention is given to the elemental composition and SEM images (Fig. 7) of the input window made of beryllium bronze (Fig. 1, position 4). The chemical compositions (wt %) of the input window from beryllium bronze were measured at two points from the center to the edges of each of the three surface regions: Point 1.1: 7.5 6C, 5.18 8O, and 87.32 29Cu. Point 1.2: 13.63 6C, 16.95 8O, 0.37 13Al, and 69.05 29Cu. Point 2.1: 20.33 6C, 42.94 8O, 30.92 13Al, 0.29 20Ca, 0.36 22Ti, and 4.54 29Cu. Point 2.2: 13.96 6C, 41.44 8O, 41.49 13Al, 0.55 22Ti, 4.5 29Cu, and 0.62 47Ag. Point 3.1: 6.87 6C, 22.18 8O, 0.75 13Al, 0.49 17Cl, and 69.7 29Cu. Point 3.2: 6.17 6C, 2.72 8O, 0.43 13Al, 88.5529Cu, and 2.14 47Ag. On the basis of the results obtained by investigating the surfaces of all components located in the DHPC, it is possible to draw the basic inference that nuclear reactions describing the fission of 46Pd nuclei in the DHPC proceed under irradiation with γ quanta. RESULTS AND DISCUSSION Let us consider all possible nuclear reactions to describe the observed phenomena. The following pro cesses occur when a dense deuterium (P = 3 kbar) and a palladium rod saturated with deuterium in the DHPC are irradiated by the flux of continuousspectrum γquanta with the threshold energy Еγ = 8.8 MeV. (i) Molecular deuterium dissociates into D atoms: γ + D2 → D + D, (2) This process must increase the pressure in the DHPC. (ii) The deuteron photofission reaction d(γ, n)р. In this case, nucleon energies must satisfy the expression En ≈ Ep = 0.5 [Еγ – ΔW].
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
DEUTERON DISINTEGRATION, THERMONUCLEAR AND NUCLEAR FISSION REACTIONS
(iii) Highenergy photoprotons and photoneutrons are elastically scattered from either deuterium atoms in its dense gas or bound D atoms in palladium:
n* + D 2, D → n*' + D*2 , D*,
(3.1)
(3.2) p* + D 2, D → p*' + D*2 , D*, Here and below, the asterisks designate ''hot'' deuteron or another particle, which can elastically or inelasti cally interact with other deuteron and D atoms, heat ing them and participating in hot synthesis reactions. It should be emphasized that the elastic scattering of charged particles depends on the structure of a solid body. In other words, they are scattered differently from amorphous and crystalline condensed media [8]. The chaotic arrangement of atoms does not create a periodic potential in the lattice, thereby excluding small energy losses observed when a particle moves under channeling conditions. The difference is explained by the fact that the scattering cross section σ varies in passing from crystalline to amorphous bodies. For amorphous targets, it is necessary to use the gas cross section σamorph = πd 2 ≈ 0.5 × 10–16 cm2 = 5 × 107 barn because a periodic potential is not produced. For a crystalline target, this value must be multiplied by the coefficient α = Θ/MS 2, where Θ is the lattice temperature (in our case, the temperature reaches ~2000°C), M is the latticeatom mass, and S is the speed of sound [8]. The speed of sound is on the order of 3 × 103 m/s. Therefore, in the case of a Pd target, the coefficient α = 0.017. However, for different target states, this coefficient can vary in the range 0.017 < α < 1.0. Thus, the cross section of a Pd single crystal is σcrys = απd 2 ≈ 8.5 × 105 barn; i.e., it is a very large value. The elastic neutronscattering cross sections σn ≈ π ⎡⎣Rn2 + Rd2 ⎤⎦ must be geometric, i.e., reach several barns, while the proton–deuteron scattering cross sec tions must be compared with the atomic gasdynamic cross sections. As is known, fast neutrons with an energy Еn > 0.1 MeV are moderated during scattering at deuterons. The moderationefficiency criterion is the average number of neutron collisions with moder ator nuclei (n = ln ⎡⎣E n0 E ⎤⎦ ξ) when the initial energy
E n0 reduces to Е [9, p.62], where ξ is the average loga rithmic loss of neutron energy per collision. In the case of deuterium, this parameter is 0.725. When neutrons are slowed from the maximum to the thermal energy (from 3.3 to 0.025 MeV), the number of collisions is 26. Thus, deuterons transfer the average energy Δ E d ≈ 130 keV. The following maximum energies are trans ferred by protons to deuterium atoms and molecules: max (4) = 8 En, p; ED2 = 16 En, p. 9 25 (iv) The thermonuclear fusion of hot deuterons with the reaction product in a dense D gas and Dsat max
ED
245
urated palladium is implemented by means of the fol lowing reactions:
d* + d → t* + p*; d* + d → 3 He* + n*,
(5.1)
t* + d → 4 He* + n*, 3 He* + d → 4 He* + p*, (5.2) However, in the above processes, the number of partic ipating particles and the cross sections decrease with decreasing particle energy. The cross sections of the D–D and D–T reactions are presented in [10, 12]. (v) The nuclear reactions (γ, n) and (γ, p) accom panied by the generation of photoneutrons and photo protons are written as A N Z (γ, n) A −1N Z and A N Z (γ, p) A −1N Z −1 , if the γquantum energy exceeds the reaction energy Q, i.e., Еγ > |Q|. (vi). Thermal neutrons are captured by atomic nuclei: A N Z (n, γ) A + 1N Z . (vii) The fission of middlemass nuclei induced by neutrons, protons, and highenergy deuterons from reactions (3)–(5) is defined as A1 Z1 A − A1 + 1 Z − Z1 + 1 ANZ(n, A1 N Z 1 ) A − A1 + 1N Z − Z 1 ; A Z N ( p, N ) N ; ANZ(d, A1N Z 1 ) A − A1 + 2 N Z − Z 1 + 1 , respectively. Note that a heavy nuclear fission reaction is feasible if the fission parameter is chosen as Z 2 A > 17 [13, p. 437]. This condition is valid beginning from the palladium nuclei at the condition Z 2 A ⎡⎣110 Pd 46 ⎤⎦ = 19.2. In [14–16], the dependence between the fission barrier of middle mass nuclei predicted by the drop nuclear model and orbital numbers is discussed. (viii) In Dsaturated palladium and a dense D gas, cold deuterium atoms are most efficiently heated due to the elastic Coulomb scattering of nuclear fission prod ucts, such as 12Mg, 13Al, 14Si, 15P, 16S, 17Cl, 18Ar, 19K, 20Ca, 22Ti, 23V, 24Cr, 26Fe, 29Cu, and 30Zn with energies of several megaelectronvolts, substantial macroscopic amounts of which were detected in the DHPC, i.e., elas tic scattering in the reactions A N Z * + D → A N Z *' + D* and A N Z * + D → A N Z *' + D *. 2
2
(ix) To estimate the reaction cross sections, the wavelength of protons with the energy Ер, λ = 4.553 × 10 −3 E 1p 2 , and the effective cross section σeff = 0.6512/Ep [MeV] barn are introduced as was done in [6]. (x) For nonresonant exothermal reactions between light charged particles and nuclei and D–D and D–T reactions, the subbarrier fusion cross sec tion is defined as ⎧ E ⎛ E ⎞⎫ ⎛ E ⎞ σ(E ) = C ⎨ G exp ⎜ − G ⎟⎬ = S exp ⎜ − G ⎟ , (6) E⎩ E ⎝ E ⎠⎭ E ⎝ E⎠
(
)
2 where EG = M 2πe02 Z 1Z 2 is the Gamow energy 2 and parameters C and S are weakly dependent on energy Е. It is obvious that the bracketed multiplier in
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
WISNIEWSKI et al.
246
(6), the socalled barrier penetrability, describes the probability that charged particles penetrate through the Coulomb barrier. To the first approximation, the multiplier C E can be represented as a product of the geometric cross section of collisions, which is pro portional to πR2, and the probability of a nuclear reac tion where colliding particles are within the action of nuclear forces, i.e., at distances r < R. This probability is proportional to the time of particle residence in the range r < R, i.e., R/V ∼ 1/E1/2. With the help of the aforementioned reactions occurring in the DHPC irradiated by γ quanta, the revealed chemical composition can adequately be described by the chain reactions of heating of cold deuterium atoms, which is caused mainly by the elas tic scattering of protons with large gas cross sections and partially by neutrons from reactions (3) and the subsequent reactions of the fusion of light nuclei and the fission of palladium nuclei (fission fragments appreciably heat deuterium atoms and molecules in Dsaturated palladium and gaseous deuterium). It is likely that hot nuclei, deuterons, play a predominant role in palladium nuclear fission processes. According to the Oppenheimer reaction [17]:
d+ N A
Z
A +1 Z ⎪⎧ p + N , → ⎨ A +1 Z +1 A Z A Z ⎪⎩ N ⇒ 1N 1 + 2 N 2 ,
(7)
where A + 1 = A1 + A2 and Z + 1 = Z1 + Z2, deuterons not only create hot protons but also split palladium nuclei [13–16]. Nuclear reactions leading to the formation of the detected chemical elements have been thoroughly dis cussed in [11, 12] and, hence, are presented without explanations. CONCLUSIONS Thus, it can be assumed that the process develops according to the following scenario: γ quanta initiate fusion–fission reactions by creating atomic deuterium with increasing pressure in the specialized highpres sure chamber filled with deuterium, stimulating deu teron photofission into highenergy protons and neu trons. These elastically scattered photoprotons and photoneutrons transfer their energies to cold deute rium atoms, heating them and creating hot deuterons. Hot deuterium atoms, i.e., deuterons, interact with cold deuterium atoms in thermonuclear fusion pro cesses to produce light fission products, such as pro tons, neutrons, tritons, 3H nuclei, which, in turn, heat deuterium atoms and interact with each other in ther monuclear fusion processes. Deuterium atoms heated according to the Oppenheimer reaction [17] repeat edly create hot protons and split palladium nuclei into lighter nuclei. These nuclei detected via microelement
analysis heat the deuterium atoms again. As a result, the process proceeds at an everincreasing rate, but some products leave the reaction, and, hence, its “replenishment” by a beam of external γquanta becomes necessary. As follows from our estimates of the energy efficiency of detected fission processes, the coefficient of efficiency can be represented as
ηDHPC =
E Ti + EPd + EFusion , βW
(8)
where ETi, EPd, EFusion, β, and W are, respectively, the energies released from the formation of titanium nuclei, the nuclear reaction of palladium fission accompanied by copper and zinc generation, the light isotope fusion reaction, and the energy required to heat the DHPC internal volume to high temperatures. Estimation of the quantities entering into (8) has been performed in [11, 12]. According to the most conser vative estimates, the coefficient of efficiency turns out to be greater than 10 (ηDHPC > 10). The developed approach can be used as a founda tion for a new type of highly efficient deuterated nuclear fission reactors (DNFRs), where the deuter ated Pd metal simultaneously plays the role of an inhibitor and an absorber of neutrons. Such DNFRs are compact and inexpensive and can supersede enriched uranium nuclear reactors. Enriched uranium itself can serve as a reactor fuel because it ensures the absorption of up to three deuterium atoms per ura nium, forming UD3 [9, 11, 12]. For authenticity, the estimated accuracies of measured concentrations are given without rounding, i.e., as was determined via XRSMA. ACKNOWLEDGMENTS This study, as well as a number of other investiga tions of deuterium and hydrogen behavior in metal foils, was supported by the cooperation program of the National Center of Nuclear Research, Poland. REFERENCES 1. M. L. Subbotin, D. K. Kurbatov, and E. A. Filimonova, Vopr. At. Nauki Tekh., No. 8, 55 (2010). 2. F. F. Chen, Introduction to Plasma Physics and Con trolled Fusion (Springer ScienceBusiness Media LLC, New York, 2006), Vol. 1. 3. K. Miyamoto, Plasma Physics for Nuclear Fusion (MIT, Cambridge, MA, 1989; Fizmatlit, Moscow, 2007). 4. B. A. Ishkhanov and I. M. Kapitonov, Interaction of Electromagnetic Radiation with Atomic Nuclei (Mosk. Gos. Univ., Moscow, 1979) [in Russian]. 5. A. Yu. Didyk, R. Wisniewski, and V. A. Altynov, JINR Commun. E172008183 (JINR, Dubna, 2008). 6. H. Bethe and P. Morisson, Elementary Nuclear Theory (Wiley, 1956; Inostr. Liter., Moscow, 1958).
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013
DEUTERON DISINTEGRATION, THERMONUCLEAR AND NUCLEAR FISSION REACTIONS 7. M. Z. Tarasko, A. S. Soldatov, and V. E. Rudnikov, At. Energ. 65, 290 (1988). 8. Yu. Yavlinslii, Nucl. Instrum. Methods Phys. Res. B 146, 142 (2009). 9. Metal Hydrides, Ed. by W. M. Mueller, J. P. Blackledge, and G. G. Libowitz (Academic, New York, 1968; Atomizdat, Moscow, 1973). 10. F. Raiola, F. Burhard, Z. Fullop, et al., Eur. Phys. J. A 27, 79 (2006). 11. A. Yu. Didyk, R.Wisniewski, Phys. Part. Nucl. Lett., 2012, vol. 9, no. 8, pp. 615–631; Preprint JINR E15 201234, Dubna, 2012. 12. A.Yu. Didyk, R.Wisniewski, Phys. Part. Nucl. Lett., 2013, vol. 10, no. 3 (180), pp. 601–620; Preprint JINR E15201235, Dubna, 2012.
247
13. K. N. Mukhin, Experimental Nuclear Physics, Vol. 1: Physics of Atomic Nuclei (Energoatomizdat, Moscow, 1983), p. 616 [in Russian]. 14. A. J. Sierk, Phys. Rev. 55, 582 (1985). 15. A. J. Sierk, Phys. Rev. 55, 2039 (1986). 16. L. G. Moretto, Nucl. Phys. A 247, 211 (1975). 17. J. R. Oppenheimer and M. Fillips, Phys. Rev. 48, 500 (1935). 18. A. Yu. Didyk, I. V. Borovitskaya, R. Vishnevskii, et al., Poverkhnost’, No. 1, 16 (2013). 19. A. Yu. Didyk, R. Vishnevskii, V. S. Kulikauskas, et al., Poverkhnost’, No. 5, 1 (2013).
JOURNAL OF SURFACE INVESTIGATION. XRAY, SYNCHROTRON AND NEUTRON TECHNIQUES Vol. 7
No. 2
2013