2011 Vol. 28, No. 3
Display Method:
2011, 28(3): 257-262.
doi: 10.11804/NuclPhysRev.28.03.257
Abstract:
Based on a semiempirical macroscopicmicroscopic nuclear mass formula——Weizsäcker-Skyrme mass formula， some ground properties of nuclei， such as the deformations, the drip lines， the shell gaps of nuclei and the αdecay energies of some superheavy nuclei have been studied. The experimental data can be reasonably well reproduced with this formula. In addition, the nuclear symmetry energy coefficient and the central position of superheavy stability island were investigated.
Based on a semiempirical macroscopicmicroscopic nuclear mass formula——Weizsäcker-Skyrme mass formula， some ground properties of nuclei， such as the deformations, the drip lines， the shell gaps of nuclei and the αdecay energies of some superheavy nuclei have been studied. The experimental data can be reasonably well reproduced with this formula. In addition, the nuclear symmetry energy coefficient and the central position of superheavy stability island were investigated.
2011, 28(3): 263-267.
doi: 10.11804/NuclPhysRev.28.03.263
Abstract:
The emission angular distributions of finalstate particles produced in 16OEmulsion (Em) collisions at 14.6 AGeV, and the azimuthal angular distributions for the black particles produced in 28SiEm at 4.5 AGeV have been studied by an isotropic fireball model. The model including transverse flow is used to describe the azimuthal distributions of midrapidity π- mesons and protons produced in CNe and CCu collisions at 3.7 AGeV. The calculated results are in agreement with the experimental angular distributions. It shows that the improved fireball model gives a good description of nucleusnucleus collisions at high energies.
The emission angular distributions of finalstate particles produced in 16OEmulsion (Em) collisions at 14.6 AGeV, and the azimuthal angular distributions for the black particles produced in 28SiEm at 4.5 AGeV have been studied by an isotropic fireball model. The model including transverse flow is used to describe the azimuthal distributions of midrapidity π- mesons and protons produced in CNe and CCu collisions at 3.7 AGeV. The calculated results are in agreement with the experimental angular distributions. It shows that the improved fireball model gives a good description of nucleusnucleus collisions at high energies.
2011, 28(3): 268-271.
doi: 10.11804/NuclPhysRev.28.03.268
Abstract:
Based on the traditional Three\|Parameter formula for extracting energy gap Δ, an improved method has been obtained through fitting the data and eliminating the impact of the isospin effect on the binding energy. We find with our new calculations that the fewer the particle number, the greater the impact of isospin, and therefore, the greater the deviation caused in the traditional method. On the other hand, the results obtained by the present method, either for nuclei in the light mass or in heavy mass region, are much closer to the results of the empirical pairing formula.
Based on the traditional Three\|Parameter formula for extracting energy gap Δ, an improved method has been obtained through fitting the data and eliminating the impact of the isospin effect on the binding energy. We find with our new calculations that the fewer the particle number, the greater the impact of isospin, and therefore, the greater the deviation caused in the traditional method. On the other hand, the results obtained by the present method, either for nuclei in the light mass or in heavy mass region, are much closer to the results of the empirical pairing formula.
2011, 28(3): 272-275.
doi: 10.11804/NuclPhysRev.28.03.272
Abstract:
In the framework of the relativistic mean field theory(RMFT), protoneutron stars with hyperons are studied. To be compatible with neutron star masses, the hyperon scalar coupling χσ should lie in the range of 0.33—0.77. As the hyperon scalar coupling increases, in protoneutron star matter, the core temperature increases whereas the abundance of neutrinos decreases. The metastable mass range of protoneutron stars narrows as the temperature increases. It is found that a protoneutron star cannot subside into a low mass black hole when χσ>0.75. Furthermore, the case of SN1987A is discussed.
In the framework of the relativistic mean field theory(RMFT), protoneutron stars with hyperons are studied. To be compatible with neutron star masses, the hyperon scalar coupling χσ should lie in the range of 0.33—0.77. As the hyperon scalar coupling increases, in protoneutron star matter, the core temperature increases whereas the abundance of neutrinos decreases. The metastable mass range of protoneutron stars narrows as the temperature increases. It is found that a protoneutron star cannot subside into a low mass black hole when χσ>0.75. Furthermore, the case of SN1987A is discussed.
2011, 28(3): 276-289.
doi: 10.11804/NuclPhysRev.28.03.276
Abstract:
We summarized both the general covariant energy\|momentum and angular momentum conservation law in the gravitational system and analyzed the general covariant energy\|momentum tensor of the gravitational system in general five\|dimensional cosmological in brane\|universe models. After calculating this energy\|momentum for the cosmological generalization of the Randall\|Sundrum(RS) model which includes the original RS model as the static limit, we are able to show that the weakness of the gravitation on the “visible” brane is a general feature of this model. This is the origin of the gauge hierarchy from a gravitational point of view. Our results are also consistent with the fact that a gravitational system has vanishing total energy. We also discussed the properties of the general covariant angular momentum in five\|dimensional brane-universe model. With calculation of the total angular momentum of this model, we analyzed the properties of the total angular momentum in the inflationary RS model. We pointed that the space-like components of the total angular momentum are zero while the others are non-zero, which agrees with the results from ordinary RS model. We also investigated the bulk cosmological constant and brane vacuum energies in RS model. We show that the five\|dimensional bulk cosmological constant and the vacuum energies of the two branes could take their natural values. Finally we argued how we can generate a small four-dimensional effective cosmological constant on the branes by modifying the original RS model.
We summarized both the general covariant energy\|momentum and angular momentum conservation law in the gravitational system and analyzed the general covariant energy\|momentum tensor of the gravitational system in general five\|dimensional cosmological in brane\|universe models. After calculating this energy\|momentum for the cosmological generalization of the Randall\|Sundrum(RS) model which includes the original RS model as the static limit, we are able to show that the weakness of the gravitation on the “visible” brane is a general feature of this model. This is the origin of the gauge hierarchy from a gravitational point of view. Our results are also consistent with the fact that a gravitational system has vanishing total energy. We also discussed the properties of the general covariant angular momentum in five\|dimensional brane-universe model. With calculation of the total angular momentum of this model, we analyzed the properties of the total angular momentum in the inflationary RS model. We pointed that the space-like components of the total angular momentum are zero while the others are non-zero, which agrees with the results from ordinary RS model. We also investigated the bulk cosmological constant and brane vacuum energies in RS model. We show that the five\|dimensional bulk cosmological constant and the vacuum energies of the two branes could take their natural values. Finally we argued how we can generate a small four-dimensional effective cosmological constant on the branes by modifying the original RS model.
2011, 28(3): 290-095.
doi: 10.11804/NuclPhysRev.28.03.290
Abstract:
In the commissioning stage of Shanghai Synchrotron Radiation Facility(SSRF) storage ring, several methods were used to correct the linear optics. Beam Based Alignment(BBA) was used for BPM\|Quadrupole offsets measurement; Response matrix was used for orbit correction; LOCO was used for linear optics fitting, and quadrupoles strength were adjusted to correction the beta function; coupling was measured and corrected by skew quadrupoles. After correction， closed orbit are reduced to 50/60 μm in hortizontal and vertical plane; β beating and dispersion errors are less than 1%; betatron tune and emmittance are closed to the design value; betatron coupling also can be adjusted from 0.02% to 2%. These methods have been proved to be useful for storage ring calibrations, with the help of these methods, SSRF storage ring can be tuned to the design model and other model easily.
In the commissioning stage of Shanghai Synchrotron Radiation Facility(SSRF) storage ring, several methods were used to correct the linear optics. Beam Based Alignment(BBA) was used for BPM\|Quadrupole offsets measurement; Response matrix was used for orbit correction; LOCO was used for linear optics fitting, and quadrupoles strength were adjusted to correction the beta function; coupling was measured and corrected by skew quadrupoles. After correction， closed orbit are reduced to 50/60 μm in hortizontal and vertical plane; β beating and dispersion errors are less than 1%; betatron tune and emmittance are closed to the design value; betatron coupling also can be adjusted from 0.02% to 2%. These methods have been proved to be useful for storage ring calibrations, with the help of these methods, SSRF storage ring can be tuned to the design model and other model easily.
2011, 28(3): 296-299.
doi: 10.11804/NuclPhysRev.28.03.296
Abstract:
One digital power supply was designed for the sextupole magnets of CoolerStorageRing of the Heavy Ion Research Facility in Lanzhou (HIRFLCSR). It adopts HBridge convertor as the main topology circuit and Cyclone II FPGA as the main hardware, and has realized fully digitized PI regulation arithmetic by Verilog language. The peak current of the power supply reaches 340 A and the stability approaches 3.14×10-5. Finally the power supply has achieved the designed specification of 1×10-4.
One digital power supply was designed for the sextupole magnets of CoolerStorageRing of the Heavy Ion Research Facility in Lanzhou (HIRFLCSR). It adopts HBridge convertor as the main topology circuit and Cyclone II FPGA as the main hardware, and has realized fully digitized PI regulation arithmetic by Verilog language. The peak current of the power supply reaches 340 A and the stability approaches 3.14×10-5. Finally the power supply has achieved the designed specification of 1×10-4.
2011, 28(3): 300-304.
doi: 10.11804/NuclPhysRev.28.03.300
Abstract:
In the classical mechanics frame and with small amplitude approximation, the longutudial motion equation of particles in quasi\|isochronous syhchrotron is reduced to the general Weierstrass equation with a damping term and a forced term. In the non-perturbed case, the phase plane properties are analysed by using Weierstrass function; in the perturbed case, the stabilities are discussed in terms of the multi\|scalar techniques.The results show that the separatrix orbit is a homoclinic orbit through the instable point in the phase plane, the surrounding area is the fish form or α\|form.The stabilities are determined by the fish area, the large the area, the better the stability; also the results show that there are ωm=2, 1/2 super\| and sub\|harmonics resonance except the main resonance ωm=1, the critical condition of an instability is found.
In the classical mechanics frame and with small amplitude approximation, the longutudial motion equation of particles in quasi\|isochronous syhchrotron is reduced to the general Weierstrass equation with a damping term and a forced term. In the non-perturbed case, the phase plane properties are analysed by using Weierstrass function; in the perturbed case, the stabilities are discussed in terms of the multi\|scalar techniques.The results show that the separatrix orbit is a homoclinic orbit through the instable point in the phase plane, the surrounding area is the fish form or α\|form.The stabilities are determined by the fish area, the large the area, the better the stability; also the results show that there are ωm=2, 1/2 super\| and sub\|harmonics resonance except the main resonance ωm=1, the critical condition of an instability is found.
2011, 28(3): 305-309.
doi: 10.11804/NuclPhysRev.28.03.305
Abstract:
The testing of a doubled-sided multi-strip silicon detector manufactured by Institute of Modern Physics of CAS and Peking University were introduced. The electrical characteristics and energy resolution, twodimensional spectrum, crosstalk were presented. The reverse leak current of each strip is smaller than 10 nA under bias voltage of 25 V. The energy resolution of strips on the front side is about 1.5%, but a little worse for the backside strips, about 3%. The level of crosstalk is about 6% for the front side, 1% for the backside. Same tests were carried out on the commercial Micron BB1 detector and a comparison was presented.
The testing of a doubled-sided multi-strip silicon detector manufactured by Institute of Modern Physics of CAS and Peking University were introduced. The electrical characteristics and energy resolution, twodimensional spectrum, crosstalk were presented. The reverse leak current of each strip is smaller than 10 nA under bias voltage of 25 V. The energy resolution of strips on the front side is about 1.5%, but a little worse for the backside strips, about 3%. The level of crosstalk is about 6% for the front side, 1% for the backside. Same tests were carried out on the commercial Micron BB1 detector and a comparison was presented.
2011, 28(3): 310-314.
doi: 10.11804/NuclPhysRev.28.03.310
Abstract:
In this paper， the MICROMEGAS detector was employed to measure the experimental parameters A and B of the first Townsend coefficient α in 6 different ratio of Ar+CO2 gas mixtures. The results indicate that the error of α is less than 13% in the condition of electron transmission rate of the mesh up to 75% and is less than 8% due to gain fluctuation of the detector.
In this paper， the MICROMEGAS detector was employed to measure the experimental parameters A and B of the first Townsend coefficient α in 6 different ratio of Ar+CO2 gas mixtures. The results indicate that the error of α is less than 13% in the condition of electron transmission rate of the mesh up to 75% and is less than 8% due to gain fluctuation of the detector.
2011, 28(3): 315-320.
doi: 10.11804/NuclPhysRev.28.03.315
Abstract:
Based on the commonly used PATFIT and MELT program, a new program package — Positron Annihilation Spectrum Analysis(PASA) with many user\|friendly applications was developed. The main modifications are: three kinds of positron analysis methods (PATFIT, MELT, Doppler) were incorporated into PASA; MELT could run independently without being in MATLAB environment; Detailed Doppler analysis program were programmed into PASA. Experiences of using the PASA program were also introduced.
Based on the commonly used PATFIT and MELT program, a new program package — Positron Annihilation Spectrum Analysis(PASA) with many user\|friendly applications was developed. The main modifications are: three kinds of positron analysis methods (PATFIT, MELT, Doppler) were incorporated into PASA; MELT could run independently without being in MATLAB environment; Detailed Doppler analysis program were programmed into PASA. Experiences of using the PASA program were also introduced.
2011, 28(3): 321-325.
doi: 10.11804/NuclPhysRev.28.03.321
Abstract:
Polycrystalline pyrochlore Gd2Ti2O7 compounds were irradiated with 400 keV Ne2+ ions at cryogenic temperature (~77 K). The irradiation fluences was ranging from 5×1014 to 1×1016 ions/cm2, corresponding to a peak ballistic damage dose of ~0.16 to 3.3 displacements per atom. Irradiation\|induced structural evolution was examined using grazing incidence X\|ray diffraction (GIXRD) at angles from 0.25° to 3° degrees. It was found that the lattice parameter increases as a function of (1) X\|ray incident angle and (2) ion irradiation fluence, suggesting that the irradiated layer is volumetrically swelled compared with the underlying un\|irradiated substrate. At ion fluence of 1×1016 ions/cm2, the irradiation layer was found to be amorphous.
Polycrystalline pyrochlore Gd2Ti2O7 compounds were irradiated with 400 keV Ne2+ ions at cryogenic temperature (~77 K). The irradiation fluences was ranging from 5×1014 to 1×1016 ions/cm2, corresponding to a peak ballistic damage dose of ~0.16 to 3.3 displacements per atom
2011, 28(3): 326-331.
doi: 10.11804/NuclPhysRev.28.03.326
Abstract:
There appears volume swelling on the surface of the irradiated rutile TiO2 crystal and the volume swelling is affected by the ion fluence and the electronic stopping power. To induce adequate irradiation damage for the chemical etching, the irradiation parameters must fulfill some requirement. There is minimum electronic stopping power for the chemical etching of the irradiated region in TiO2 crystal， which is about 8. 2 keV/nm. If the ion fluence is below 1×1013ions/cm2, the saturated etching depth of the irradiated region in TiO2crystal cannot be reached. The irradiation damage based on latent track formation frame and the theoretical linkage to the etching technique is investigated. It is hopeful to fabricate microand nanoscale structurce in rutile TiO2 crystal by using the ion irradiation and chemical etching technique.
There appears volume swelling on the surface of the irradiated rutile TiO2 crystal and the volume swelling is affected by the ion fluence and the electronic stopping power. To induce adequate irradiation damage for the chemical etching, the irradiation parameters must fulfill some requirement. There is minimum electronic stopping power for the chemical etching of the irradiated region in TiO2 crystal， which is about 8. 2 keV/nm. If the ion fluence is below 1×1013ions/cm2, the saturated etching depth of the irradiated region in TiO2crystal cannot be reached. The irradiation damage based on latent track formation frame and the theoretical linkage to the etching technique is investigated. It is hopeful to fabricate microand nanoscale structurce in rutile TiO2 crystal by using the ion irradiation and chemical etching technique.
2011, 28(3): 332-336.
doi: 10.11804/NuclPhysRev.28.03.332
Abstract:
Irradiation experiments of gallium nitride (GaN) with 2.3 MeV20 Ne8+ and 5.0 MeV84 Kr19+ respectively were performed. The irradiated samples were analyzed using the high\|resolution X\|ray diffraction (HRXRD) spectrometry. It was found that the diffraction peak of GaN (0001) exhibited regular shift to smaller diffraction angles with the increase of ion fluence for the both ions， and the diffraction peak split into a few sub\|peaks at higher irradiation dose. Underlying mechanisms of the observed peak shift and split were investigated, the contributions of different energy losses to the damage accumulation in the irradiated GaN were discussed.
Irradiation experiments of gallium nitride (GaN) with 2.3 MeV20 Ne8+ and 5.0 MeV84 Kr19+ respectively were performed. The irradiated samples were analyzed using the high\|resolution X\|ray diffraction (HRXRD) spectrometry. It was found that the diffraction peak of GaN (0001) exhibited regular shift to smaller diffraction angles with the increase of ion fluence for the both ions， and the diffraction peak split into a few sub\|peaks at higher irradiation dose. Underlying mechanisms of the observed peak shift and split were investigated, the contributions of different energy losses to the damage accumulation in the irradiated GaN were discussed.
2011, 28(3): 337-342.
doi: 10.11804/NuclPhysRev.28.03.337
Abstract:
In this paper it was investigated that the effect of modeled microgravity on the acute injury induced by low doses of carbon ions in the male reproductive organs of mice, assessing the risk associated with the space environments. In our study, outbred Kunming mice were stimulated in microgravity by tail suspension, and then were irradiated with the low doses of carbon ions diliuered by HIRFL, and measured the testis and epididymis coefficient, sperm number of epididymis, histological alterations, DNA strand breaks and cell apoptosis. The results demonstrated that carbon ions and stimulated microgravity could induce the damage in the present study. Moreover, most serious injury all occurred in the irradiation group. In addition, it was also found that the damage of the carbon ion irradiation combined microgravity group were lower than those of the irradiation group, while the related mechanism needs the further investigation.
In this paper it was investigated that the effect of modeled microgravity on the acute injury induced by low doses of carbon ions in the male reproductive organs of mice, assessing the risk associated with the space environments. In our study, outbred Kunming mice were stimulated in microgravity by tail suspension, and then were irradiated with the low doses of carbon ions diliuered by HIRFL, and measured the testis and epididymis coefficient, sperm number of epididymis, histological alterations, DNA strand breaks and cell apoptosis. The results demonstrated that carbon ions and stimulated microgravity could induce the damage in the present study. Moreover, most serious injury all occurred in the irradiation group. In addition, it was also found that the damage of the carbon ion irradiation combined microgravity group were lower than those of the irradiation group, while the related mechanism needs the further investigation.
2011, 28(3): 343-348.
doi: 10.11804/NuclPhysRev.28.03.343
Abstract:
To investigate the M1 biological effects of heavy ions irradiation on Lycopersicon esculentum Mill., its seeds were irradiated by 12C6+heavy ions (80 MeV/u) with the dosages of 30, 60, 90, 120 and 160 Gy respectively . The results showed that with doses increased gradually, germination rate and seedling rate of Lycopersicon esculentum Mill. were decreased, and the latter was lower than the former, mainly due to the inhibition of root growth. The irradiation increased the content of MDA and proline evidently, showing irradiation could damage biomembrane, and also decreased the activities of POD and SOD with distinct inhibition pattern. However, the low dose and high dose irradiation promoted APX activity, illustrating APX was induced to protect irradiation injury. In brief, exposure to 12C6+ heavy ions had obvious injury effects on the seeds of Lycopersicon esculentum Mill.. Heavy ions irradiation damaged biomembrane, inhibited activities of enzymes, and finally inhibited the growth of the first generation of these seeds.
To investigate the M1 biological effects of heavy ions irradiation on Lycopersicon esculentum Mill., its seeds were irradiated by 12C6+heavy ions (80 MeV/u) with the dosages of 30, 60, 90, 120 and 160 Gy respectively . The results showed that with doses increased gradually, germination rate and seedling rate of Lycopersicon esculentum Mill. were decreased, and the latter was lower than the former, mainly due to the inhibition of root growth. The irradiation increased the content of MDA and proline evidently, showing irradiation could damage biomembrane, and also decreased the activities of POD and SOD with distinct inhibition pattern. However, the low dose and high dose irradiation promoted APX activity, illustrating APX was induced to protect irradiation injury. In brief, exposure to 12C6+ heavy ions had obvious injury effects on the seeds of Lycopersicon esculentum Mill.. Heavy ions irradiation damaged biomembrane, inhibited activities of enzymes, and finally inhibited the growth of the first generation of these seeds.
2011, 28(3): 349-353.
doi: 10.11804/NuclPhysRev.28.03.349
Abstract:
To investigate the M1 biological effects of heavy ions irradiation on Lycopersicon esculentum Mill., its seeds were irradiated by 12C6+heavy ions (80 MeV/u) with the dosages of 30, 60, 90, 120 and 160 Gy respectively . The results showed that with doses increased gradually, germination rate and seedling rate of Lycopersicon esculentum Mill. were decreased, and the latter was lower than the former, mainly due to the inhibition of root growth. The irradiation increased the content of MDA and proline evidently, showing irradiation could damage biomembrane, and also decreased the activities of POD and SOD with distinct inhibition pattern. However, the low dose and high dose irradiation promoted APX activity, illustrating APX was induced to protect irradiation injury. In brief, exposure to 12C6+ heavy ions had obvious injury effects on the seeds of Lycopersicon esculentum Mill.. Heavy ions irradiation damaged biomembrane, inhibited activities of enzymes, and finally inhibited the growth of the first generation of these seeds.
To investigate the M1 biological effects of heavy ions irradiation on Lycopersicon esculentum Mill., its seeds were irradiated by 12C6+heavy ions (80 MeV/u) with the dosages of 30, 60, 90, 120 and 160 Gy respectively . The results showed that with doses increased gradually, germination rate and seedling rate of Lycopersicon esculentum Mill. were decreased, and the latter was lower than the former, mainly due to the inhibition of root growth. The irradiation increased the content of MDA and proline evidently, showing irradiation could damage biomembrane, and also decreased the activities of POD and SOD with distinct inhibition pattern. However, the low dose and high dose irradiation promoted APX activity, illustrating APX was induced to protect irradiation injury. In brief, exposure to 12C6+ heavy ions had obvious injury effects on the seeds of Lycopersicon esculentum Mill.. Heavy ions irradiation damaged biomembrane, inhibited activities of enzymes, and finally inhibited the growth of the first generation of these seeds.
2011, 28(3): 354-365.
doi: 10.11804/NuclPhysRev.28.03.354
Abstract:
Based on the spherical optical model, preequilibrium statistical theory, and HauserFeshbach theory, etc., the code MEND (Medium Energy Nuclear Data) is written for calculating the complete set of nuclear data of mediumheavy nuclei in mediumlow energy region (≤250 MeV). For the reactions induced by neutron and proton below 250 MeV, the total cross sections, reaction cross sections, elastic scattering differential cross sections, double differential cross sections and energy spectra, etc. calculated by the code MEND, generally agree with those corresponding experimental data. MEND is a foundational program for nuclear reaction in mediumlow energy region and is wildely used for nuclear data calculation and establishing ENDF/B6 format files of mediumlow energy region in China.
Based on the spherical optical model, preequilibrium statistical theory, and HauserFeshbach theory, etc., the code MEND (Medium Energy Nuclear Data) is written for calculating the complete set of nuclear data of mediumheavy nuclei in mediumlow energy region (≤250 MeV). For the reactions induced by neutron and proton below 250 MeV, the total cross sections, reaction cross sections, elastic scattering differential cross sections, double differential cross sections and energy spectra, etc. calculated by the code MEND, generally agree with those corresponding experimental data. MEND is a foundational program for nuclear reaction in mediumlow energy region and is wildely used for nuclear data calculation and establishing ENDF/B6 format files of mediumlow energy region in China.
2011, 28(3): 366-370.
doi: 10.11804/NuclPhysRev.28.03.366
Abstract:
The secondary neutron emission doubledifferential cross section of 9Be induced by 8.19 MeV neutron was measured at 26 different angles from 20°to 150°by using the multidetector fast neutron TOF spectrometer at the HI 13 Tandem Accelerator at China Institute of Atomic Energy(CIAE). The results were normalized to np scattering measurement. A special MonteCarlo code which was validated with the MCNP 4C code was employed to analyze the measured data for the corrections of neutron flux attenuation, multiple scattering and finite geometry. The measured results were compared with the evaluated data and the other measurements.
The secondary neutron emission doubledifferential cross section of 9Be induced by 8.19 MeV neutron was measured at 26 different angles from 20°to 150°by using the multidetector fast neutron TOF spectrometer at the HI 13 Tandem Accelerator at China Institute of Atomic Energy(CIAE). The results were normalized to np scattering measurement. A special MonteCarlo code which was validated with the MCNP 4C code was employed to analyze the measured data for the corrections of neutron flux attenuation, multiple scattering and finite geometry. The measured results were compared with the evaluated data and the other measurements.
2011, 28(3): 371-376.
doi: 10.11804/NuclPhysRev.28.03.371
Abstract:
Lithium\|lead alloy is considered to be one of the most prominent tritium breeding materials for the fusion reactor blanket because of its high breeding ratio, and low reactivity and possible use as coolant. An out\|of\|pile experiment of tritium release from Li17Pb83 alloy was performed after neutron irradiation on the base of mathematical model to describe tritium release behavior from an eutectic lithium\|lead alloy. The results suggest that the dominant chemical form of the released tritium (>99%) was the water\| insoluble component (HT or T2). Tritium residence time decreased with increasing H2pressure in carrier gas up to 1000 Pa, and above this concentration limit it became constant and not influenced by the plenum volume. The temperature dependence of the tritium release rate can be described by an Arrhenius law. Consequently, the present results on the kinetic parameters of tritium in molten Li17Pb83alloy are considered to be different from the values in literature, but it is the same that the overall release process is governed by the diffusion of tritium atoms in the Li17Pb83and by the heterogeneous reaction at the gas\|eutectic interface of the tritium atom recombination at temperatures from 633 to 973 K.
Lithium\|lead alloy is considered to be one of the most prominent tritium breeding materials for the fusion reactor blanket because of its high breeding ratio, and low reactivity and possible use as coolant. An out\|of\|pile experiment of tritium release from Li17Pb83 alloy was performed after neutron irradiation on the base of mathematical model to describe tritium release behavior from an eutectic lithium\|lead alloy. The results suggest that the dominant chemical form of the released tritium (>99%) was the water\| insoluble component (HT or T2). Tritium residence time decreased with increasing H2pressure in carrier gas up to 1000 Pa, and above this concentration limit it became constant and not influenced by the plenum volume. The temperature dependence of the tritium release rate can be described by an Arrhenius law. Consequently, the present results on the kinetic parameters of tritium in molten Li17Pb83alloy are considered to be different from the values in literature, but it is the same that the overall release process is governed by the diffusion of tritium atoms in the Li17Pb83and by the heterogeneous reaction at the gas\|eutectic interface of the tritium atom recombination at temperatures from 633 to 973 K.
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