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Nuclear Science, IEEE Transactions on

Issue 6 • Date Dec. 1974

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Displaying Results 1 - 25 of 76
  • [Front cover]

    Publication Year: 1974 , Page(s): c1
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  • [Inside front cover]

    Publication Year: 1974 , Page(s): c2
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  • Table of contents

    Publication Year: 1974 , Page(s): 1
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  • Scenes and faces at the 1974 conference

    Publication Year: 1974 , Page(s): 6 - 7
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  • Summary of 1974 IEEE annual conference on nuclear and space radiation effects

    Publication Year: 1974 , Page(s): 8
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    The eleventh IEEE Annual Conference on Nuclear and Space Radiation Effects was held in Fort Collins, Colorado on July 15–18, 1974 on the campus of Colorado State University. More than 290 attended. The Conference was officially sponsored by the Radiation Effects Committee of the IEEE Nuclear and Plasma Sciences Society in cooperation with the Office of Conferences and Institutes, Colorado State University and partially supported by the Defense Nuclear Agency. View full abstract»

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  • The nucleus

    Publication Year: 1974 , Page(s): 9
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    For nearly a decade, the December issue of the Transactions on Nuclear Science has contained selected papers from the IEEE Annual Conference on Nuclear and Space Radiation Effects. Considered collectively, these December issues probably constitute the most important source of documented technical information for workers in the field of applied radiation effects. Papers presented at this year's conference are indicative of the broad range of technical interests found in the radiation effects community. Papers in Session 1 are concerned with the basic mechanisms of interactions between radiation and solid materials. Such phenomena are examined for technologically important insulators and semiconductors. One feature of this first session is a series of papers dealing with the basic aspects of radiationinduced effects in materials employed a s gate insulators in MOS transistors. Related papers on MOS devices are contained in Session 3. A topic dealt with in several Session 3 papers is the effects of ionizing radiation on CMOS/SOS structures. Session 2 contains papers describing radiation effects on a variety of devices, ranging from silicon transistors to fiber optic waveguides. View full abstract»

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  • IEEE nuclear and plasma sciences [committees]

    Publication Year: 1974 , Page(s): 10
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  • Reviewers for this issue

    Publication Year: 1974 , Page(s): 11
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  • Outstanding paper award — 1974 IEEE conference on nuclear and space radiation effects

    Publication Year: 1974 , Page(s): 12 - 13
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  • Luminescence in electron irradiated CdS

    Publication Year: 1974 , Page(s): 14 - 20
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    Electron irradiation induced changes in both the photo- and cathodo-luminescence spectra of high purity CdS platelets have been monitored over a wavelength range from 4800Å to 2 μm. The irradiations were all performed near 10K using beam energies from 100 keV to 1 MeV. By irradiating with electron energies between the cadmium and sulfur displacement thresholds, and above the cadmium displacement threshold, the damage induced luminescence could be assigned to specific sublattices. In the bound exciton spectral region near the band edge, all exciton lines present before irradiation were observed to decrease in intensity with the exception of the emission line at 4867Å. This line was observed to grow in absolute intensity for irradiation energies above the sulfur displacement threshold. We attribute the 4867Å emission to the decay of an exciton bound to a shallow neutral donor state associated with the sulfur vacancy. The edge emission was found to decay in intensity when observed by photoluminescence but to increase in intensity when excited by 100 keV electrons following an irradiation above the sulfur displacement threshold. Broad band luminescence has also been produced by irradiation at 7200Å and 1.03 μm. The 7200 Å band is not observed, however, until a thermal anneal is performed above a recovery stage centered at 180 K. The edge emission and bound exciton emission partially recover in this same temperature range. Another annealing stage is observed at 230 K by monitoring the intensity of emission bands at 1.03 and 1.65 μm. The annealing stage at 180 K is associated with sulfur sublattice damage recovery while the stage at 230 K is due to recovery of cadmium sublattice damage. View full abstract»

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  • Photoabsorption effects in low temperature electron-irradiated Germanium

    Publication Year: 1974 , Page(s): 21 - 25
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    Photoconductivity measurements performed under carefully controlled conditions have revealed that the dominant defects in low temperature, electron irradiated n-type Ge are optically active, double-acceptor type defects which thermally anneal at a temperature around 65°K. The stability of these defects is sensitive to temperature, background light levels, irradiation fluenced and fluxes, and probably impurity type and concentration. It is concluded from the results of this and other studies that the optically active defect is probably an isolated vacancy. View full abstract»

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  • Calculated displacement damage by neutrons in InSb

    Publication Year: 1974 , Page(s): 26 - 29
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    Displacement damage in InSb is calculated for 1MeV and 14MeV incident neutrons. Ranges and energy deposition profiles are calculated with the E-DEP-1 computer code and combined with published neutron cross sections to obtain atomic displacement rates and range distributions. The damage ratio of 14MeV to 1MeV neutrons is estimated as close to unity. Comparison results are presented for Si. Experimental verification for unity damage ratio is given. View full abstract»

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  • Effects of irradiation on the electrical and optical properties of PbSnTe

    Publication Year: 1974 , Page(s): 30 - 33
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    Radiation effects on the electrical conductivity, Hall mobility, and carrier density were studied on three different types of p-type PbSnTe samples. One type (sample 1) was vapor-grown with an initial carrier density of ∼4 &time; 1016 cm−3, and was irradiated with 30-MeV electrons at 78°K. Another type (sample 2), which was cut from a solid-state recrystallized boule and then annealed to lower its carrier concentration to ∼8 &time; 1017 cm−3, was also irradiated with 30-MeV electrons at 78°K. The other type of specimen (sample 3) was an epitaxially deposited thin film on a BaF2 substratum, with a carrier concentration of ∼4 &time; 1017 cm−3. It was electron-irradiated at 9°K and subsequently gamma- and neutron-irradiated at 78°K. Temperature dependence of the optical transmission for sample 3 was performed to determine the radiation dependence of the energy bandgap. View full abstract»

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  • Radiation effects on the spectral response of HgCdTe

    Publication Year: 1974 , Page(s): 34 - 39
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    We present a theoretical model for the effects of electron irradiation on the bulk electronic energy band parameters of HgCdTe. The material is treated as degenerate. We predict irradiation induced changes in the shape of spectral response and resolve apparent inconsistencies in the HgCdTe photoresponse data. Qualitative, overall changes in photoconductive detector response are predicted and we find a general trend that short wavelength materials are less susceptible to the effects of radiation. View full abstract»

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  • Electron damage in In2Te3 — A defect tetrahedral semiconductor

    Publication Year: 1974 , Page(s): 40 - 46
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    Indium sesquitelluride (In2Te3) is typical of a large class of defect semiconductors which are tetrahedrally bonded but which possess room temperature vacancy concentrations of the order of 5.5 &time; 10 cm−3. It has been proposed by V.M. Koshkin et al. that these semiconductors can not preserve non-equilibrium point defect concentrations. This hypothesis has been tested in the present experiments by electron irradiating In2Te3 at 77 K with 1 MeV electrons and using electron paramagnetic resonance (EPR) to observe the results. Several different resonances have been observed with g values ranging from 1.979 to 2.133 and possessing X-band line widths of 7 to 42 gauss. All of the resonances except the largest one at g = 2.019 have orientation dependent g values and all anneal at different temperatures suggesting that several different defect centers have been produced. Because the 1 MeV electron defect production rate for these centers at 77 K (0.01 to 0.1 defects/electron) is typical of defect production rates observed in other compound semiconductors, the hypothesis proposed by Koshkin et al. is incorrect. The stability of these defects is somewhat lower than in non-defect semiconducting compounds, however, since none of these defects survive prolonged room temperature annealing and since no additional complex centers formed by thermal annealing have been detected. View full abstract»

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  • Rapid annealing and charge injection in Al2O3 MIS capacitors

    Publication Year: 1974 , Page(s): 47 - 55
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    Rapid annealing after radiation and field injection characteristics of Al2O3 MIS capacitors have been investigated by means of a fast C-V measurement technique. The results indicate that electron injection under positive bias and trapping of radiation-generated holes are dominated by an interface transition region at the Si-Al2O3 interface which need not extend further than 20–30 A from the Si substrate to account for the observations. The field injection charging characteristics are well described by a model invoking direct tunneling of electrons from the Si valence band into electron traps in the interface transition region with an energy distribution consistent with field-injected photo-depopulation studies. View full abstract»

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  • Effects of stoichiometry on the radiation response of SiO2

    Publication Year: 1974 , Page(s): 56 - 61
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    Defect center production in irradiated silica is shown to exceed that found in stoichiometric SiO2. The defect centers observed are the E′ type which are associated with oxygen vacancies. It is suggested that a large concentration of E′ centers is expected near the oxygen deficient Si-SiO2 interface of irradiated MOS devices and that the presence of these defects is one source of positive space charge buildup within the first hundred Angstroms of the oxide. In addition, the 4500Å emission band observed in irradiated SiO2 has been shown to be associated with the decay of E′ centers. View full abstract»

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  • Effects of ion bombardment on Na and Cl motion in SiO2 thin films

    Publication Year: 1974 , Page(s): 62 - 66
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    The effects of light and heavy ion bombardment on Na and Cl motion in SiO2 thin films have been studied using proton-induced characteristic x-ray (PIX) and Rutherford backscattering (RBS) techniques. Results show that both Na and Cl atoms may be trapped in the oxides by implantation damage. Release does not occur under ionizing irradiation (proton bombardment). Partial release or motion does occur after annealing to 700°C or by further heavy ion bombardments. Na motion is consistent with the movement of single Na+ ions in the oxide. In contrast, the movement of Cl atoms appears to be dominated by enhanced Cl diffusion or by motion of positive Cl-defect complexes whenever heavy ion bombardment damage is introduced. View full abstract»

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  • Sodium mobility in irradiated SiO2

    Publication Year: 1974 , Page(s): 67 - 72
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    The distribution of sodium in the oxide films of MOS capacitors was determined by etch-off procedures, using sodium-22 as a tracer. The effects on sodium distribution of ionizing radiation, of in-diffused aluminum, and of bias-temperature stressing were then determined and compared with C-V measurements of the total oxide charge in the same samples. Aluminum films sintered for 30 minutes at 500°C provided high aluminum concentrations (∼1020/cm3) in the oxide near the surface, while sintering for 60 minutes caused aluminum to diffuse about three times deeper. In both cases low concentrations (∼1018/cm3) were found next to the silicon. Aluminum-rich portions of the oxide were found to trap sodium, and thus the oxides with the 30-minute aluminum sinter had very little sodium concentrated near the silicon substrate (0.2 to 0.6 &time; 1011/cm2); the interfacial sodium accounted for only 2% of the oxide charge determined by C-V measurements. Oxides without aluminum or with 60-minute aluminum sinter had nearly 10-fold higher interfacial sodium concentrations (1 to 6 &time; 1011/cm2) and this interfacial sodium accounted for 10% of the oxide charge from C-V measurements. Ionizing radiation (106 rads in one hour from cobalt-60 at 25°C with a positive bias of 106 volts/cm) increased the total oxide charge by 14 to 17 &time; 1011 electronic charges/cm2, but caused very small increases, in interfacial sodium (0.2 to 0.9 &time; 1011 ions/cm2). However, the combination of ionizing radiation followed by positive bias stress (106 volts/cm) at 300°C for 10 minutes caused an appreciable movement of sodium to the interface in some of the oxides, especially those with no aluminum or with aluminum sintered for 60 minutes. Positive bias at 300°C - or 10 minutes in aluminum-doped oxides caused large increases in negative voltage shifts (corresponding to an increase of 10 to 20 &time; 1011 positive charges per cm2) but in the same tests no more than 3 &time; 1011 sodium ions per cm2 moved into the oxide next to the silicon substrate. These results suggest that the drift of positively charged aluminum interstitials may be the cause of much of the voltage shift in 300°C tests. View full abstract»

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  • Charge transport studies in SiO2: Processing effects and implications for radiation hardening

    Publication Year: 1974 , Page(s): 73 - 80
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    Charge transport studies have been performed on SiO2 films using an electron-beam injection technique. MOS capacitors incorporating oxides grown at 1000 and 1100°C were investigated, including units fabricated at Hughes Aircraft using radiation hardening procedures. A comparison of beam-induced current vs field characteristics is made for devices with differing processing histories. Additionally, experimental determinations of trapped positive charge vs collected charge were performed. Present findings indicate that holes are mobile in SiO2, that the schubweg model is insufficient for describing charge transport in SiO2 films, and that the electron-hole pair creation energy for SiO2 is ≤ 19 eV. Current vs field data can be qualitatively explained in terms of columnar and/or geminate recombination. Conclusions concerning the effects of processing on charge buildup are made and a qualitative model based on experimental findings is presented. Implications of this model for radiation hardening are discussed. View full abstract»

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  • The effects of radiation on the absorption and luminescence of fiber optic waveguides and materials

    Publication Year: 1974 , Page(s): 81 - 95
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    Irradiation of fiber optic waveguides with X-rays, gamma-rays, electrons, or neutrons can cause luminescence and losses in optical transmission. These effects have been measured, using pulsed and continuous radiation sources, in bulk materials and in most commercially available fiber bundles. Some important effects of dopants and impurities such as Ge, Ti, Fe, Al, and OH on radiation-resistance have also been determined. Transient absorption and luminescence were measured from 10 ns to 0.1s after irradiation (10 to 106 rads and 109 to 1013 rads/sec), and the permanent absorption was measured from 24 to 72 hours after irradiation (103 to 109 rads). These results show that synthetic vitreous silica (undoped), some doped silicas, polymethylmethacrylate and polystyrene can be used in radiation environments that are encountered in space and military applications. The utility of each of these fibers depends on the particular radiation environment, the length of waveguide, the wavelength of signal light, the time any system can be “off the air”, and constraints imposed by fiber cost. The data can be used to determine the response of actual fiber systems during and after irradiation. View full abstract»

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  • Performance of Ga1−xAlxAs light emitting diodes in radiation environments

    Publication Year: 1974 , Page(s): 96 - 102
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    Addition of aluminum as a cation substituent in GaAs improves the relative radiation hardness of the GaAs light emitting diode, as deduced from both gamma and neutron irradiation experiments to 108 rads (Si) and 3.5&time;1013 neutrons/cm2, respectively. The gamma damage coefficient, Ky, shows a marked and unexpected decrease from 52 (rads (Si) .s)−1 to ∼ 2 (rads(Si) .s)−1 in the composition range from GaAs to ∼ Ga.90Al 10AS. Above 10 percent Al content, the damage coefficient changes only slightly. On the other hand, the neutron damage coefficient Kn shows a gradual change over the entire compositional range from 0 to 34 percent aluminum. Annealing of the gamma-irradiated samples indicates that the 240° C stage noted for GaAs and attributed to an arsenic vacancy is reduced with addition of aluminum. On the other hand the annealing of the Ga1−xAlxAs samples following neutron irradiation indicates that the annealing characteristics are virtually independent of the aluminum composition. For both types of irradiation there is a shift of the peak emission wavelength to shorter wavelengths following irradiation. View full abstract»

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  • Fast neutron irradiation damage on room temperature PbS detectors

    Publication Year: 1974 , Page(s): 103 - 106
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    The effects of high-energy neutron irradiation on the photoconductive properties of chemically-deposited PbS infrared detectors have been investigated in the I011 n/cm2 to 1014 n/cm2 fluence range. Long term degradation in signal response has been observed subsequent to room temperature irradiation of 2×1012 n/cm2 or greater fluetices. Seventy-five percent of the degradation can be attributed to a reduction in majority carrier lifetime, and the most likely source for the additional 25% reduction in the photoconductivity is the quantum efficiency. However, the degradation is not permanent. The recovery proceeds logarithmically with time. The dark resistance was unaffected by the irradiation. Additionally, if the detector views a visible light source simultaneously with the neutron irradiation, a significant increase in signal degradation rate is found. View full abstract»

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  • Ionizing radiation dosimetry and noise in small geometry devices

    Publication Year: 1974 , Page(s): 107 - 112
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    A code is presented to predict the statistics of transient responses to gamma radiation of rectangular solid state devices. Use of the chordlength distribution and assuming the radiation flux isotropic obviates use of Monte Carlo techniques, so that the code runs fast enough for exploratory use. It is discovered that, for small detectors, relatively large-area non-square thin detectors are advantageous. View full abstract»

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  • Permanent and transient radiation induced losses in optical fibers

    Publication Year: 1974 , Page(s): 113 - 118
    Cited by:  Papers (1)
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    With the deployment of fiber optic data transmission links in military and domestic communications systems which may be subjected to various levels of ionizing radiation it is of interest to determine both the permanent and transient radiation-induced optical transmission loss in both fibers and relevant bulk glasses. Loss produced by both Co60 γ-irradiation and by pulsed electron (0.5 MeV) irradiation in both high-loss and low-loss fibers is presented. Luminescence for some hundreds of microseconds following pulsed electron irradiation of low-loss fibers is briefly discussed in terms of possible electromagnetic interference effects. View full abstract»

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IEEE Transactions on Nuclear Science focuses on all aspects of the theory and applications of nuclear science and engineering, including instrumentation for the detection and measurement of ionizing radiation; particle accelerators and their controls; nuclear medicine and its application; effects of radiation on materials, components, and systems; reactor instrumentation and controls; and measurement of radiation in space.

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