Showing papers in "IEEE Transactions on Nuclear Science in 1969"
TL;DR: In this paper, the authors measured the resistivity, temperature, and injection level dependences of the minority carrier lifetime in neutron irradiated p- and n-type silicon, and compared the predictions of two alternate models for recombination at defect clusters.
Abstract: Measurements are reported which provide extensive data on the resistivity, temperature, and injection level dependences of the minority carrier lifetime in neutron irradiated p- and n-type silicon. The lifetime damage constants are observed to be quite dependent on the injected minority carrier density, in both conductivity types, over the temperature range from 76°K to 300°K. The low injection level damage constants have been measured and found to be dependent on material resistivity in p-type silicon, but only slightly dependent on resistivity in n-type silicon. The results of the experimental studies are compared to the predictions of two alternate models for recombination at defect clusters. For defect clusters of approximately 250 A radius, as expected from range calculations, these comparisons indicate that each contains a relatively small number of deep defects (30 - 40). The defects are individually characterized by a deep donor level near Ev + 0.35 eV and a deep acceptor level near Ec - 0.50 eV. Since these levels correspond approximately to the known energy levels of the silicon divacancy, it is suggested that the divacancy may be the active recombination center within the defect clusters.
77 citations
TL;DR: In this article, the use of electron paramagnetic resonance (EPR) as a "microscopic" tool in the study of radiation-produced defects in semiconductors is discussed.
Abstract: This is the text of a tutorial talk on the use of electron paramagnetic resonance (EPR) as a "microscopic" tool in the study of radiation-produced defects in semiconductors. The basic concepts of EPR and its general applicability to point defects in semiconductors are outlined. As an illustrative example, the study of a p-type (aluminum doped) silicon sample is described from 20.4°K irradiation with 1.5 MeV electrons through various annealing stages. By analysis of the EPR spectra, it is shown that the major defects can be identified and the annealing mechanisms determined.
76 citations
TL;DR: In this paper, the authors provide an insight into low frequency divergent noises with spectral density |f|?, where?? -1, and into their effect on physical measurements, with special reference to 1/|f| noise.
Abstract: The purpose of this paper is to provide an insight into low frequency divergent noises with spectral density |f|?, where ? ? -1, and into their effect on physical measurements, with special reference to 1/|f| noise. This class of noise is widespread in nature, and it presents unique limitations to the measurement accuracy. In an attempt to present a picture of this class of noise with regard to the measurements of observable physical quantities, the questions about generation of noise, its divergence, correlation properties and measurements of variance are discussed. A statistical model for generation of low frequency divergent noises is used to consider the divergence problem in both the frequency and time domain. It is shown that 1/|f| noise is "weakly divergent," and that power limitation presents no reason to impose a low frequency limit within time intervals observable in nature. Correlation properties are discussed in terms of the time-dependent correlation function, using an ideal impulse response which generates low frequency noise from white noise. Two general models for generation of 1/|f| noise are summarized and discussed. Generation of 1/|f| noise from white noise over a limited frequency range by distributed and lumped-parameter filters is described. It is shown that the variance (i.e. mean square noise) is determined by the frequency limits of the observation method.
61 citations
TL;DR: A model based on structural modifications of the silicon-dioxide-films is proposed for the build-up of interface-states resulting from exposure to radiation in this article, and it has been found that with the proper doping of the Silicon-Dioxide films, the buildup of such states can be reduced.
Abstract: Interface-state densities and MOS transistor characteristics dependent upon such states have been studied as a function of radiation dose and type. Special MOS devices possessing doped silicon-dioxide layers as well as undoped "control" devices have been utilized. Infrared absorption measurements were performed on silicon-dioxide samples before and after exposure to radiation, as well as for doped and undoped samples. A model based on structural modifications of the silicon-dioxide-films is proposed for the build-up of interface-states resulting from exposure to radiation. It has been found that with the proper doping of the silicon-dioxide films, the build-up of such states can be reduced. Using such doped gate-dielectrics, planar semiconductor devices much less sensitive to radiation have been fabricated.
59 citations
TL;DR: The Sandia Laboratories Hermes II has produced a 170 kA beam of electrons at energies of 12 million volts for times of 100 ns as mentioned in this paper, which is the state-of-the-art performance.
Abstract: Pulsed power technology has grown rapidly during the last decade. Particular credit is due to research efforts at United Kingdom Atomic Weapons Research Establishment (AWRE). The largest machine presently in operation is the Sandia Laboratories Hermes II which has produced a 170 kA beam of electrons at energies of 12 million volts for times of 100 ns. This paper reviews the design and performance of the Hermes II and includes data from Hermes I, a prototype.
44 citations
TL;DR: In this paper, the authors discuss the physical mechanisms responsible for radiation-induced latchup in ICs and propose a method to identify latchup-prone structures within an IC and apply appropriate electrical testing during the IC production phase to determine the V-I characteristics of these paths.
Abstract: This paper discusses integrated circuit (IC) structures and associated physical mechanisms which are responsible for the phenomenon of radiation-induced latchup. Laboratory measurements on selected IC's haveverifiedthatthestructures described will support latchup. These measurements are briefly discussed. An important result of the laboratory measurements has been to establish that electrical tests can be used to identify latchup-prone structures within an IC. These measurements, together with an understanding of the biasing conditions that must exist in order to initiate the latchup path, can be used to determine the susceptibility of an IC, in normal operation, to radiation-induced latchup. A careful analysis of a given IC's topology can uncover all latchup-prone structures. Once such structures have been identified, appropriate electrical testing can be implemented during the IC production phase to determine the V-I characteristics of these paths. This procedure will supply the necessary information regarding the biasing conditions required for the initiation of the latchup paths when the IC is exposed to an ionizing radiation environment. One-hundred percent electrical testing may be required, depending upon the results of the analyses, in order to uncover the single latchup-prone individual, among several hundred IC chips, which might possess an anomalous V-I characteristic. It is concluded that four-layer (p-n-p-n) action is the primary latchup sustaining mechanism, while transistor sustaining voltage breakdown is of little concern and second breakdown is probably of minor importance for most IC's. Second breakdown must be given careful consideration, however, before a given IC can be considered to be latchup free.
44 citations
TL;DR: In this article, the authors focus on the design of low temperature enclosures for high energy particle production of the accelerator proper and consider the advantage of rapid cooldown time against the amount of cooling power.
Abstract: For many years an ability to achieve and work at low temperatures has been useful to experimentalists performing certain types of high energy physics research. In fact, the demands of physics have been largely responsible for cryogenic technology as it stands today. Ten years ago or so, the increase in size of bubble chambers beyond capacities of a few liters of liquid was a significant event. The larger liquid hydrogen chambers being commissioned today depend not only on liquid hydrogen technology, but in another significant step, on liquid helium technology for successful operation of the superconducting magnets surrounding the detectors. The effort required to conceive, design, start up and operate these auxiliary low temperature devices has been enormous and there have been many problems, eventually solved, which at one time or another have hampered operation. The term “auxiliary devices” is emphasized because never before has the high energy particle production of the accelerator proper been dependent upon a continuous low temperature environment. The character of some of the next generation of accelerators which are being conceived and dis cussed now, shifts the burden of planning for the cryogenic environment from the detector experts to those responsible for particle production. The dimension added to accelerator design by low temperature elements must be accounted for from the time of earliest planning. Assurance of reliable operation is critical to the physics experiments and the provision of redundant components should be carefully considered. Cryogenic safety should be planned simultaneously so that it can actually be built into the system rather than be added as an afterthought. The difficult logistics problem of distributing refrigeration to widely separated consumption sites will probably require a different solution for each experimental area or accelerator geometry considered. To a large extent, the method chosen will determine the capital and operating costs, affect the reliability and influence the design of the low temperature enclosures. Among other things, the entire system design must consider the advantage of rapid cooldown time against the amount of
41 citations
39 citations
TL;DR: In this article, the amplitude of the electrical currents obtained by collecting these ions onto a variety of electrodes depends on the distribution of the protons in the beam, and both analog and digital techniques have been used to determine beam position and profile.
Abstract: The nondestructive beam detector systems originated at Argonne National Laboratory allow continuous measurement of the proton beam position and beam profile in the Zero Gradient Synchrotron (ZGS) during the accelerating and targeting cycle. Nondestructive detection is accomplished by collecting the ions produced by the proton beam ionizing residual gas in the vacuum chamber. The amplitude of the electrical currents obtained by collecting these ions onto a variety of electrodes depends on the distribution of the protons in the beam. The characteristics of the electric signals make them suitable as inputs to computer systems. Both analog and digital techniques have been used to determine beam position and profile. These beam detection systems have been used for measuring the properties of the 50 MeV beam between the injector linac and the synchrotron ring; for studying the steering and the radial growth of the size of the beam during acceleration; and for measurements during the targeting sequences.
36 citations
TL;DR: In this paper, a channel multipliers for spectral analysis of low-energy (0.5-500 keV) electrons and protons at synchronous altitude on the ATS-E satellite is presented.
Abstract: A compact channel-multiplier instrument has been designed and developed for spectral analysis of low-energy (0.5-500 keV) electrons and protons at synchronous altitude on the ATS-E satellite. The instrument package, which weighs 1.3 kg, contains 11 sensors and features a completely automatic in-flight calibration system for the interrogation of sensor and electronic performance. A detailed discussion of experimental objectives and design and calibration data for the instrument is presented. The results of studies of the long-term behavior of channel-multipliers is emphasized.
34 citations
CERN1
TL;DR: In this article, the results of a radiation testing program on swept-synthetic quartz resonators and materials were reported, showing that the drift due to the temperature change induced by a radiation pulse equilibrates, a relatively permanent frequency offset which changes with dose is observed.
Abstract: In this paper we report the results of a radiation testing program on swept-synthetic quartz resonators and materials. Thirteen resonators representing eight bars of Z-growth, swept-synthetic quartz were tested for transient frequency drifts and accumulated frequency offset. When the drift due to the temperature change induced by a radiation pulse equilibrates, a relatively permanent frequency offset which changes with dose is observed. Typical frequency changes are found to be approximately +2 pp 108 for doses of a few kilorads to about 5 × 104 rads and -1 pp 107 after 2 × 105 rads. Crystals cut from the same bar exhibit frequency shifts which differ by about 1 pp 108 for a given dose, but crystals from different bars differ by larger amounts for a given dose. Changes observed in a resonator irradiated in a mixed gamma-neutron environment to 175 kilorads and 3 × 1014 n/cm2 cannot be accounted for by ionization-induced changes alone. Positive frequency shifts, linear in neutron fluence, are observed. Electron spin resonance and transient and steady-state optical absorption measurements were performed on pieces of the parent material in an attempt to correlate the observed frequency changes with defect properties. Two radiation-induced electron spin resonance centers were observed, one of which appears to anneal at the same temperature as the frequency shift due to ionizing radiation. Predictions of frequency shifts with accuracies of approximately 1 pp 107 can be made from measurements of a piece of a bar.
TL;DR: In this article, the interface state densities at the Si/Silicon Oxynitride (SiON) interface before and after ionizing irradiation, on extended B T tests on Si/SiON capacitors, and on the fabrication and properties of SiON passivated bipolar transistors and P-channel IGFETs.
Abstract: We report here on the interface state densities at the Si/Silicon Oxynitride (SiON) interface before and after ionizing irradiation, on extended B T tests on Si/SiON capacitors, and on the fabrication and properties of SiON passivated bipolar transistors and P-channel IGFETs. Preliminary data are also presented for gold and copper diffused capacitor structures. The fast state density Nfs after a 1/2 hr. anneal in H2 at 900°C is approximately 8x1010 eV-1 cm-2 near midgap, and increases into the high 1011 eV-1 cm-2 range near the band edges. After an absorbed dose of 1.3 Mrads, the densities near midgap had increased by a factor of 1.3, but showed little change near the band edges. B-T tests under negative bias at l.6×106 V/cm and at temperatures up to 330°C showed a Vfb drift of 2-3 V to more positive values during the first hour, which did not change thereafter; very little drift occurred under positive bias and the same test condition. Test duration was 63 hours for either polarity of bias. This BT-stability, observed on Si/SiON/Al structures, is often lost after gold wire thermocompression bonding. Si/SiON/ tungsten-gold contacts showed no deterioration after thermocompression bonding. SiON passivated type 16F NPN bipolar transistors had initial gain characteristics similar to SiO2 passivated controls, whereas their tolerance to ionizing radiation was much greater. Degradation of hFE to 50% of the initial gain occurred for the SiO2 passivated devices after an absorbed dose of about 1 Mrad and for the SiON passivated devices after 35 Mrads.
TL;DR: In this article, a survey of the theoretical and experimental data obtained in the last eight years about both the shape of the pulses supplied by semiconductor detectors and the techniques for obtaining from these pulses a fast timing information is presented.
Abstract: In this paper a survey is presented of the theoretical and experimental data obtained in the last eight years about both the shape of the pulses supplied by semiconductor detectors and the techniques for obtaining from these pulses a fast timing information Moreover the problem is considered of extracting from the shape of the pulse some information on the type or the impact angle of the detected radiation
TL;DR: In this article, the Nevis Synchrocylotron magnet was tuned so that fmin = fextraction including a slow linear RF turnoff where df/dt? 0 for adiabatic energy damping.
Abstract: The for the revised Nevis Synchrocylotron magnet will increase from 18 kG at the center to 20 kG at 80 in. radius. This gives 27.48 MHz at injection, and 19.23 MHz for extraction (550 MeV, 76 in. radius). The resonator will be tuned so that fmin = fextraction including a slow RF turnoff where df/dt ? 0 for adiabatic energy damping. The peak dee voltage ? 30 kV with the maximum near injection. The repetition rate will be 300 Hz with < 50% RF duty factor. The single dee and dee stem structure will be ~ 150 in. wide and 163 in. long. One of the three pairs of sector-iron shims is to be incorporated into the dee and the assembly supported on cooled alumina structural insulators. The resonator frequency is varied by two rotating capacitors located at the end of the dee stem, which is split outside the magnet circle. Excitation of the resonator will be provided by a grounded-grid, triode oscillator having the anode and cathode coupled to the resonator via coupling loops and transmission lines of proper length and impedance. A series tube modulator will permit the slow linear RF turnoff needed for adiabatic energy damping of the phase oscillations before extraction.
TL;DR: A number of groups are engaged in improvement of synchrocyclotrons in order to increase beam current and improve beam extraction efficiency and beam precision as discussed by the authors, and the major problems involved in such improvements and the solutions contemplated by the several groups.
Abstract: A number of groups are engaged in improvement of synchrocyclotrons in order to increase beam current and improve extraction efficiency and beam precision. This paper reviews the major problems involved in such improvements and the solutions contemplated by the several groups. Goals are beams of 10?a or more with extraction efficiency of at least 50% and a tenfold gain in spatial and energy definition of the beams.
TL;DR: In this paper, an accelerator to produce a beam with currents of the order of several hundred amperes has been in operation at the Lawrence Radiation Laboratory, Livermore, for several years.
Abstract: One of the primary requirements of the Astron controlled thermonuclear reactor experiment is an intense beam of relativistic electrons. An accelerator to produce such a beam with currents of the order of several hundred amperes has been in operation at the Lawrence Radiation Laboratory, Livermore, for several years. The accelerator operates on the principle of magnetic induction as applied to a linear accelerator. The original accelerator has been redesigned and rebuilt in order to increase the output beam current, to increase the beam energy, and to improve the quality of the output beam. Given in Table I is a comparison between the original machine and the design parameters for the new machine.
TL;DR: In this article, measurements of minority carrier lifetime damage constant and divacancy growth following neutron irradiation at 76°K have been used to characterize further the annealing of neutron damage in silicon below 300°K.
Abstract: Measurements of minority carrier lifetime damage constant and divacancy growth following neutron irradiation at 76°K have been used to characterize further the annealing of neutron damage in silicon below 300°K. It has been shown that electron injection into p-type silicon at 76°K causes recovery of the neutron induced defect clusters with the simultaneous appearance of divacancies. Comparison of isochronal annealing curves of damage constant taken with and without prior injection at 76°K illustrates the nature of cluster annealing below 300°K. The thermal annealing results are shown to agree with previous annealing measurements of the carrier removal rate.
TL;DR: In this paper, complementary symmetry MOS (CMOS) integrated circuits were subjected to a sub-microsecond burst of high intensity ionizing radiation using 10-MeV electrons from a LINAC.
Abstract: Complementary-symmetry MOS (CMOS) integrated circuits were subjected to a sub-microsecond burst of high intensity ionizing radiation using 10-MeV electrons from a LINAC. The results show that, at peak doserate values of less than 8 × 108 rads (Si)/s, the transient change in output voltage of a CMOS inverter is small and can be attributed simply to the net junction photocurrent flowing at the output node. At dose rates in excess of 8 × 108 rads (Si)/s, however, a new type of response comes into play and the transient change in output voltage becomes very large, approaching the operating voltage. In some instances, this change can result in a non-destructive temporary latch-up condition. The results suggest that this condition is caused by a parasitic effect, namely the interaction of the P-well, the source-drain diffusions, and the protection diodes that constitute a four layer structure.
TL;DR: Compton scattering of ruby laser light from a high energy electron beam at SLAC has been employed to produce a highly polarized, partially monochromatic photon beam of energy up to 7 GeV.
Abstract: Compton scattering of ruby laser light from a high energy electron beam at SLAC has been employed to produce a highly polarized, partially monochromatic photon beam of energy up to 7 GeV.
TL;DR: A review of the current status of electron and positron storage rings is presented in this article, where the experimental results on beam instabilities, their consequences on the design of a high current sto rage ring and the technological problems involved are discussed.
Abstract: A review of the current status of electron and positron storage rings is presented. The experimental results on beam instabilities, their consequences on the design of a high current sto rage ring and the technological problems involved are discussed.
TL;DR: In this article, the performance of photomultipliers having first dynodes of cesium-activated GaP with gains of from 30 to 50 is discussed, where the resolution capabilities are high enough so that the pulse height distribution obtained from low intensity scintillations breaks up into separate peaks for one electron, two electrons, etc.
Abstract: The performance of photomultipliers having first dynodes of cesium-activated GaP with gains of from 30 to 50 is discussed. The resolution capabilities are high enough so that the pulse height distribution obtained from low intensity scintillations breaks up into separate peaks for one electron, two electrons, etc. This high resolution makes it possible to separate unwanted single electron dark pulses from the scintillation signal pulses very effectively. The full width at half maximum (FWHM) of a single electron pulse height distribution is typically 40% to 50%. Methods of measuring the resolution of these tubes are discussed together with some of the results obtained. These high gain dynodes appear to have good life characteristics. Their life and fatigue properties are as good or better than those of CuBe dynodes.
TL;DR: In this paper, the EG&G/AEC electron linear accelerator was used to achieve 50 ps in duration with a precision of 30 ps, which results in pulse-to-pulse reproducibility to within a few percent, permitting recurring pulse measurements with sampling oscilloscopes.
Abstract: Radiation pulses 50 ps in duration have been attained at the EG&G/AEC electron linear accelerator by isolation of individual microstructure groups of electrons which normally occur at the fundamental accelerating frequency. Pulse compression by means of velocity modulation techniques has been used to increase the intensity of these pulses from 0.02 nC to 1.5 nC per pulse, or 30 A for the 50-ps pulse length. The injector pulse is synchronized to the RF acceleration frequency with a precision of 30 ps, which results in pulse-to-pulse reproducibility to within a few percent, permitting recurring pulse measurements to be made with sampling oscilloscopes. These intense short bursts of radiation allow the study of radiation detectors, scintillators, and chemical systems in the subnanosecond time domain. Neutron time-of-flight measurements with a total resolution of 400-500 ps have also been demonstrated. The calculated charge enhancement resulting from velocity-modulation bunching is compared to measured performance, and the system is described in detail.
TL;DR: In this article, ultrasonic thermometry based on the temperature dependence of sound velocity in solids has been demonstrated under ideal laboratory conditions beyond 6000 R. Ta protective sheaths prevented carbon contamination for 1 hr at 5100R, in a program simulating temperature measurements in the graphite/hydrogen atmosphere of a nuclear rocket engine, and separately, inside a 1.6 mm dia Ta tube heated to 5500R, simulating temperatures inside UO2-fueled pins of fast breeder reactors.
Abstract: Ultrasonic thermometry, based on the temperature dependence of sound velocity in solids, has been demonstrated under ideal laboratory conditions beyond 6000R. Integrated fluxes (nvt) of 2.6 × 1019 fast and 8.7 × 1019 thermal do not perturb the velocity/temperature relationship. Ta protective sheaths prevented carbon contamination for 1 hr at 5100R, in a program simulating temperature measurements in the graphite/hydrogen atmosphere of a nuclear rocket engine. Tests have also been performed in liquid sodium at 1200R, and separately, inside a 1.6 mm dia Ta tube heated to 5500R, simulating temperatures inside UO2-fueled pins of fast breeder reactors.
TL;DR: In this article, the effects of radiation on silicon Schottky barrier diodes were investigated and the p-n junction guard ring structure and a gate-controlled structure were used to separate surface from bulk effects.
Abstract: Because of a variety of important new applications, it is desirable to determine the effects of radiation on silicon Schottky barrier diodes. In the present study, both neutron and low-energy electron irradiation were employed and a variety of Schottky diode structures were investigated. These included the p-n junction guard ring structure and a gate-controlled structure which was used to separate surface from bulk effects. The two main effects of low-energy electron irradiation are: increase of surface recombination velocity and buildup of a positive space charge in the oxide. These results are consistent with previous studies of p-n junction diodes. For Schottky diodes without gate electrodes, the breakdown voltage is decreased and some excess current is present at low forward bias after irradiation. The effects of nuclear irradiation are (in addition to the surface effects mentioned above): decrease of bulk lifetime and carrier removal, again consistent with previous studies on p-n junction devices. Recombination-generation current increases manyfold due to the decrease in lifetime after irradiation. This component of current is important for Pt Schottky diodes which have a high barrier (0.85 eV). However, for Al diodes, since the barrier is relatively low (0.69 eV) and the thermionic emission current relatively high, recombination-generation current is not important until very high neutron dosage.
TL;DR: In this paper, the energy linearity for Si(Li) and Ge(Li), compared with theory, has been measured and compared with the experimental results, and good agreement was obtained for x-ray attenuation factors?md < 100.
Abstract: The energy linearity for Si(Li) and Ge(Li) has been measured and compared with theory. Good agreement was obtained for x-ray attenuation factors ?md < 100 . The region of the germanium absorption edge was investigated and found to exhibit larger nonlinearities than predicted by the theory. The discrepancy is believed to be due to inefficient charge collection near the detector window leading to excessive fluctuations in the trapped charge. Calculations of the line broadening due to trapping have been shown to agree qualitatively with experimental values for the silicon detector. These calculations do not take into account any position dependent variation of the trapping factor, and must therefore be considered as the best attainable values. The disagreement between theory and experiment for the line broadening in Ge(Li) is particularly evident. The ? seems to be independent of energy in Si to less than 0.2% and in Ge to within at least 2% . Finally, the Fano factor in Si was found to be 0.154 +0.1 -0.2.
TL;DR: In this article, the authors derived the optimum area-balanced waveform giving least noise for a defined overall width, and compared it with the unipolar cusp and also with several practical bipolar systems.
Abstract: A nuclear pulse spectrometer should have both low noise and minimal sensitivity to slow disturbing signals, e.g. base-line fluctuations due to long CR-couplings. A bipolar filter weight-function (or step response) with area balance is advantageous for the latter, but generally involves increased noise and/or resolving time. This paper derives the optimum area-balanced waveform giving least noise for a defined overall width. Optimum waveforms are illustrated and the noise/signal performance is compared with that of the finite-width unipolar cusp and also with several practical bipolar systems in common use.
TL;DR: In this article, the design and calibration results of a satellite based solar-cosmic ray particle identifier system utilizing a field effect transistor analog multiplier for the IMP F and G spacecraft are described.
Abstract: The design and calibration results of a satellite based solar-cosmic ray particle identifier system utilizing a field effect transistor analog multiplier for the IMP F and G spacecraft are described. A discussion is made of the effectiveness of particle separation by such a particle identifier used in on-board data processing.
TL;DR: In this paper, the performance characteristics of silicon surface barrier detectors have been investigated for detecting H+, He+, N+, Ne+ and Ar+ in the energy interval 6-100 keV.
Abstract: The performance characteristics of silicon surface barrier detectors have been investigated for detecting H+, He+, N+, Ne+ and Ar+ in the energy interval 6-100 keV. For a cryogenically cooled, 50 mm2, 1325? depletion depth detector the resolution for protons was 1.65 keV (FWHM). The resolution decreased as the particle mass increased being 6.5 keV for 40 keV Ar+. All particles exhibit pulse height linearity throughout the energy range.