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Numbers of citations of outstanding conference papers (OCPs) of IEEE Nuclear and Space Radiation Effects Conferences (NSRECs) from 1966 to 2017 are compared with citations of the most highly cited papers (HCPs) of the corresponding special issues of the IEEE TRANSACTIONS ON NUCLEAR SCIENCE (TNS), as well as average numbers of citations and cumulative $h$ index, $h_{\mathrm {cum}}$ , for all TNS papers published in the same year. 85% of NSREC OCPs are cited at a higher rate than the average for all TNS articles in that year. 55% of NSREC OCP citation totals are higher than $h_{\mathrm {cum}}$ for TNS in that year; these rank among the ~8% most highly cited TNS papers for that year. In ~10% of cases, the NSREC OCP is also the most HCP. Similarly high citation impact is found for papers nominated as candidates for OCPs. Radiation effects papers published in annual NSREC special issues comprise a significant fraction of all TNS articles cited $h_{\mathrm {cum}}$ times or more. These results support the use of $h_{\mathrm {cum}}$ as a metric of citation impact in this work and show that the NSREC OCP process generally meets awards criteria guidelines for impact. Potential reasons for variations in citation rates are discussed, and recommendations are provided to enhance the awards process.

The IEEE Transactions on Nuclear Science (TNS) Best Paper Award is an annual award recognizing the most significant paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of the papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2021 award is, therefore, awarded to the paper published in the calendar year 2018, judged to be the most useful to our community based on metrics calculated for the years 2018–2020.

The IEEE Transactions on Nuclear Science Best Paper Award is an annual award recognizing the most significant paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of the papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2020 award is, therefore, awarded to the paper published in the calendar year 2017, judged to be the most useful to our community based on metrics calculated for the years 2017–2019.

IEEE Transactions on Nuclear Science (TNS) is pleased to announce that Prof. Gian-Franco Dalla Betta (S’94–M’98–SM’06) was appointed as Senior Editor receiving papers on Radiation Instrumentation in June 2020. He replaced Prof. Arnold Burger who had served in this position since early 2016. Prof. Burger handled over 1600 original papers and revisions during his tenure, and we are grateful for his service.

IEEE Transactions on Nuclear Science (TNS) is pleased to announce that Prof. Yuntao Wu was appointed Associate Editor, receiving papers on radiation instrumentation in November 2020.

The IEEE Transactions on Nuclear Science Best Paper Award is an annual award to recognize the best paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2019 award is, therefore, awarded to the paper published in calendar year 2016 judged to be the most useful to our community based on metrics calculated for the years 2016, 2017, and 2018.

This conference presents the recipients of the Outstanding Conference Paper Award from the 2015 IEEE Nuclear and Space Radiation Effects Conference.

IEEE Transactions on Nuclear Science is pleased to announce that Dr. Sang-Ho Kim has been appointed as an Associate Editor for Accelerator Technology papers.

This paper integrates the results of numerous nuclear utility industry meetings with commercial business practices. The Central Procurement Organization (CPO) is designed to achieve an immediate 30%-50% reduction in total procurement, engineering qualification, warehousing, and distribution cost. Three (3) areas define a CPO success criteria: (1) Lean, credible, and cost-effective issues discussed include facility cost, operational cost, staff expertise, product priorities, warehousing, and distribution, (2) Common technical, commercial, and quality requirement issues discussed include current industry practices and proposed future methodologies, and (3) Financial survivability issues which are the most critical since the CPO must exist during changing internal and external utility environments. Areas discussed are financial return criteria, liabilities, and survivability in the competitive marketplace. Alternative implementation of CPO structures, consisting of utility groups, a single utility, and/or partnering with commercial firms, are discussed considering the current industry environment.

This paper identifies a selection of papers presented at the NSREC and published in the IEEE TRANSACTIONS ON NUCLEAR SCIENCE that have had measurable impact on radiation effects research and the radiation effects community. Criteria include papers selected for the Outstanding Paper Award at the NSREC or papers from the NSREC that have been highly cited by authors of other journal publications. Additionally, several papers are identified that, even though they are not selected by the above criteria, have impacted the technical areas served by the NSREC. Some observations are made on the methodology used here for selecting high-impact papers.

The recipients of the 1994 NSREC Outstanding Conference Paper Award are Gordon Hopkinson of SIRA Ltd., Isobel Hopkins of SIRA/UCL Postgraduate Centre, and Bengt Johlander of ESA/ESTEC, for their paper entitled, "Proton-Induced Charge Transfer Degradation in CCDs for Near-Room Temperature Applications." The paper describes an innovative optical technique for measuring charge transfer inefficiency in CCDs operated in the near-room-temperature-range of -30°C to 30°C. The optical spot technique enables the measurement of CTD dependence on signal size, background charge, and clock waveform shape, as well as trap emission times, as a function of these variables. The technique involves spot illumination of the CCD, followed by repeated charge transfer regimes. It is applicable to any CCD and yields improved accuracy over the x-ray method. The paper reflects strong current interest in CCD hardness issues as these devices become more pervasive in space applications

Determination of the distribution of oxide charge and interface properties is important to an understanding of oxide charging phenomena such as that produced by irradiation. The physical mechanism dominating the voltage dependence of photoinjected currents in SiO2 is the scattering of electrons in the region of the oxide between the injecting electrode and the image force potential maximum. Since the spatial position of the potential maximum depends on the electric field resulting from space charge in the oxide as well as the field due to the applied voltage, analysis of the V-I characteristics of photoinjected currents can provide information about the spatial location of oxide charge. Presented in this paper are the results of an analysis of the effects of oxide space charge on the voltage dependence of photoinjected currents. It is shown that charge distribution in SiO2 can be nondestructively profiled over a range from about ten to several hundred angstroms from the injecting electrode. Since photoinjection V-I characteristics depend on electric field at the potential maximum in the oxide, whereas C-V characteristics depend on the field just inside the semiconductor, analysis of both characteristics permits distinction between charge in t e oxide a distance greater than about 10 A and charge located at the interface.

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.

A good central region yields a compact, dense, well-centered beam in a phase interval which will optimize the following acceleration and extraction processes. This paper reviews the role of various central region features in attaining desired beam properties. Results of careful calculations are shown to closely agree with observed beam properties.

The salient features of the resonance extractio ystem for the MSU cyclotron have already been described in a series of studies includings the generation of turn separation via the resonance mechanism, the design calculations for the electrostatic and magnetic channels, and the development of the air-core magnetic channel. A report issued in connection with this conference describes the status and presents pertinent data on the performanc of the cyclotron, including the extraction system. Since the issuing of that report, the electrostatic channel has been installed for preliminary tests. Experiments have verified that a suitable field bump drives the beam into this channel with clean turn separation, and that the turn pattern observed under these conditions agrees with orbit computations; the upper part of Fig. 1 shows the turn patter obtained from the differential and integral probe with the deflector in place (the azimuth of the probe is 160° before that of the channel entrance). The air-core magnetic channel is approaching completion and when this channel is installed, the extraction system will beame fully operational.

During the last few years a program has been under way at Oak Ridge National Laboratory to measure the electron flux in an irradiated medium. A typical source consists of several curies of beta radioactivity uniformly dispersed in a metal, the whole approximating a homogeneous, uniformly and isotropically irradiated medium. The electron flux escaping from a cavity within the medium is measured over the energy range from about 50 keV down to 1 eV. At the higher energies the flux observed is due entirely to the beta rays from the source, whereas below 10 keV the flux rises by as many as five orders of magnitude, this rise being due to the generation of secondary, tertiary, quarternary and higher generations of electrons. The measurements are in approximate agreement with the Spencer-Fano theory of electron slowing down above ten keV, but tend to indicate that the theory underestimates the flux below this energy by as much as a factor of four. Theoretical ionization and plasmon cross sections for aluminum have been combined with our flux data to calculate the probability of occurrence of a given type of event from a beta ray from a copper-64 or gold-198 source. Calculations show that most K-ionizations (~3) are caused by the primary beta ray whereas L-shell ionizations and plasmon excitations tend to come from the secondary electrons (~300 for the former and ~20,000 for the latter).

Discussion is restricted to low and medium energy cyclotrons. Some reasons for using external injection are given. At the present time injection is either in the median plane or axial. Among the possibilities for injection in the median plane are cycloidal motion along a sector edge, linear motion by electrostatic compensation, and high energy injection with trapping into cyclotron orbits by change of charge. In the axial direction all methods have much in common--focussing down a hole in the magnet pole and inflection into a cyclotron orbit. As an example of the problems and possibilities with external injection the axial method is discussed in more detail. Topics include basic principles, beam quality, variable energy arrangements, bunching and the choice of injection energy.

The ERA scheme being studied at the University of Maryland with collaboration of NRL and NBS involves the formation of the electron ring in a static rather than pulsed magnetic field. The main technical features, present status of the project and future plans are reviewed. Preliminary experimental studies with a 2 MeV injector are being carried out at NBS. A 5-MeV injector will be built by NRL. Extensive theoretical investigations have been carried out and design work for the compressor and expansion-acceleration system is in progress.

Although AVF cyclotrons have been in operation only for a relatively short period an impressive number of experiments have been performed and much work is also currently being done. The available time for this talk is too short, of course, to give an exhaustive survey of what has been achieved in Europe during the last year and I must select some typical experiments for presentation, apologizing to those authors, whose work I cannot mention.

This work is a review of regenerative beam extraction for synchrocyclotrons and isochronous cyclotrons. The linear and nonlinear theories of the system for synchrocyclotrons are briefly reviewed. The problems for the extraction efficiency and external beam quality are discussed. A theory for isochronous cyclotrons is given. Finally, present operating features of the systems and future prospects are summarized.

Negative hydrogen ions are accelerated at a fixed magnetic field. The energy of an extracted beam is determined by the radius of a stripping foil and its azimuth and radius determine the exit point of the beam from the cyclotron. The exit points can be adjusted so that an auxiliary magnet causes the various extracted beams to enter a common beam transport system. Since February, 1966, external beams whose energy is variable from 25 to 50 MeV have been produced by the above means at UCLA and the University of Manitoba. While this is primarily a report on the UCLA system and its performance, special features of the Manitoba system are presented.

With the continuing evolution of the various types of meson factories the relative merits of the H- spiral ridge eyclotron appear to be improving. The development and design of such an accelerator has been led by UCLA. Recently three universities in British Columbia have combined personnel for a design study intended to lead to an H- meson facility called TRIUMF - Tri University Meson Facility). Among the various meson factories the H- facility is the only one which combines the following advantages: (1) large duty factor; (2) variable energy; (3) ease of beam extraction; (4) use of simultaneous beams; (5) high beam quality. Until recently it faced two problems: (a) uncertainty about field dissociation of negative ions; (b) lack of polarized ion sourees. Recent UCLA measurements of field dissociation and the advent of polarized H- ion sources and axial injection into cyclotrons remove these problems. The field dissociation measurements agree with Hiskes' calculations and enable the use of higher fields than previously proposed for H- facilities. The TRIUMF project concerns a machine whose beam characteristics (maximum energy 500 MeV; maximum beam radius 271 inches; beam current 20-100 ?A) were selected for optimum use in nuelear structure experiments, for low cost and for operating simplieity.

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.

The possibility of increasing the output of fm cyclotrons is being explored simultaneously in many laboratories. Space charge seems to be the limiting factor. Practically every laboratory is investigating a form of hooded source known as the Livingston, calutron or Oak Ridge source. The ions must clear such a source so higher dee voltages are needed. The higher dee voltage is desirable in any case since the beam usually increases as some power of this voltage (if the repetition rate is increased correspondingly). The theoretical picture indicates a variation between V and V2. Some fm cyclotrons will try to increase performance by this method alone. Others will include all the possible improvements including a complete sector field near isochronism which will provide strong vertical focusing and reduce the frequency swing. The largest machines will probably try to achieve their goal by small sectors near the source and somewhat lareer limited radii sectors on the poles (with an unchanged radial profile). The status of these efforts is reviewed and some data on the Berkeley model program is given. It appears that most fm cyclotrons will eventually be partially or wholly converted to sector focused synchrocyclotrons.

For the extraction of the beam in an AVF cyclotron a regenerative system or an electrostatic channel can be used. Some factors of importance for the beam will be discussed. Extraction with an electrostatic channel can give very high external beam quality and extraction efficiency. For such a system it is of importance whether the beam is extracted before or after the ?R=1 resonance. The beam can even pass the ?R=2?Z resonance without blowing up vertically if attention is being paid to the radial oscillation amplitude and some machine parameters. The general orbit theory can be used for an analytical study of a regenerative system in an A.V.F. cyclotron.

Since their advent six years ago polarized ion sources have been successfully installed in 15 accelerators of various types around the world, including FF, FM, and isochronous cyclotrons. The advantages of sources over nuclear reactions for providing polarized particles are (1) greater intensity, (2) control of polarization mode and direction, and (3) freedom from background radiation from the primary target. Currently operating polarized ion sources can produce several tenth-microamperes of up to 80% polarized protons or 100% polarized deuterons and negative ion currents a thousand times smaller. Basic principles and recent developments in polarized ion source design and technology will be reviewed, with particular reference to the problems peculiar to cyclotrons. Some of the major contributions to polarized ion source development have been made at cyclotrons laboratories, first at CERN and later at Saclay, where the powerful adiabatic passage process for inducing hyperfine transitions has been extensively developed. More recently, the achievement of axial injection at Birmingham and the successful acceleration of polarized particles in the isochronous cyclotrons there and at Saclay indicate that polarized ion sources installed on this latest range of cyclotrons could provide the most powerful tool yet for examining nuclear polarization phenomena in the intermediate energy region.

The goal is a continous external proton beam of the order of 100 ?A, the usable current depending mainly on extraction rate because of activation. The energy of 500 MeV is best suited to produce high fluxes of low energy or stopped mesons. The main fields of the research are planned to be: properties and interactions of mesons and nucleons, nuclear structure physics and medical and biological applications. The use of internal targets in field free regions as well as external targets should provide a great variety of beams for simultaneous experiments. The two-stage accelerator has a 70 MeV sector focussed cyclotron for injection into an isochronous ring accelerator consisting of eight spiral sector magnets. Four cavities operating at 50 MHz should provide at least 1 MeV energy gain per turn. In the course of present development the main fields of work are orbit dynamics and measurement on 1:5 scale magnets and design of a 1:1 model magnet sector. vZ is to be kept around 0.95 throughout acceleration and vr = 1.5 may be used for resonance extraction. Experiments to reach high gap voltage on a full scale cavity in vacuum are in progress (200-300 kV obtained at present). Remaining problems are some aspects of mechanical structure, in particular the vacuum chamber and schemes for quantitative extraction and secondary beam production from external targets at very high radioactivity levels. Funds of 21 Million Dollars have been approved for construction of accelerator and buildings.

The importance and relationship of cyclotron beam characteristics to various experiments are discussed, and examples of some of the influences are given. The beam properties considered include phase-space density, energy, energy-spread, energyvariability, energy stability, and duty factor.

Charge-state effects in displacement damage in covalent semiconductors are reviewed. Specifically the influence on defect production mechanisms, configurations, mobility, annealing kinetics, interaction and dissociation are discussed. The recent theoretical work on the split-interstitial is mentioned, as is the new athermal migration mechanism.

A brief introductory review is given of the various mechanisms which govern the interaction of organic materials with ionizing radiation. Emphasis is given to the phenomena occurring in organic polymers, their explanation and the techniques used in the study of these effects.

In the present work a review of the acheivements of the Gossick and Crawford model of disordered regions in semiconductors is given, together with a transmission electron microscope investigation of the structural characteristics of the disordered regions themselves. Both diffraction contrast and phase contrast electron microscope images have been used to examine disordered regions observed in Ge irradiated with fast neutrons or 100 keV oxygen ions. Experimental evidence is presented which clearly demonstrates that the disordered regions have an amorphous rather than a defect rich crystalline structure. Furthermore, each disordered region is observed to be surrounded by a non-uniform strain field extending out to ~65A from the disordered region center.

The separated-orbit cyclotron (SOC) is a cyclic accelerator which combines the advantages of the isochronous cyclotron, the synchrocyclotron, and the linear accelerator. In an SOC, injected ions are accelerated by radio frequency cavities interspersed with the sectors of a magnet structure that guides and focuses the beam along a fixed spiral path. The magnet structure, intersected radially at equal azimuthal intervals by the rf cavities, is designed so that the time per revolution of the particles is independent of their energy, as in an isochronous cyclotron, and it may incorporate any of the well-known methods for focusing ions, such as are used in various types of synchrocyclotrons. The particles accelerated in the SOC are phase focused with respect to a synchronous phase angle corresponding to a chosen rate of energy gain and a peak accelerating voltage. This is made possible by the independent magnetic focusing for the separated orbits since the transverse dimensions of the beam are much smaller than the separation between adjacent turns, 100% beam extraction efficiency should be easily achieved. Variable energy can be obtained by moving the extraction magnet to intercept all of the beam at the right turn for the energy desired. The original concept of the SOC featured a spiral-helix ion path, sometimes called "beehive," Fig. 1, in which the orbit separation necessary to accommodate the independent magnet structure for successive turns was gained mainly by axial displacement.

A novel guide-magnet configuration has been devised which makes possible the acceleration of all charge-to-mass ratios from 0.04 to 1. A concentric storage ring, with the associated beam-switching equipment, allows for the extension of beam duty factor to essentially 100%. The storage ring can also be used in a bootstrap acceleration of heavy ions in which the ions are injected at low e/m, accelerated to a moderate velocity, stored while the accelerating ring returns to minimum field, stripped to maximum e/m, and re-injected for further acceleration. With a pressurized 2.5 MV Cockcroft-Walton injector, the proposed system is capable of accelerating all ions from protons to uranium--to energies up to 1.5 BeV for protons and 0.3 to 0.5 BeV/nucleon for the heavier ions. Intensities of 1012 to 1013 nucleons/sec for the lighter ions (M ? 128) are anticipated. The heavy-ion charge-exchange probabilities determine the vacuum requirements of this system. To minimize these requirements and to increase beam intensity, a 60/sec cycling rate has been chosen. The vacuum requirements and the special rf resonator and beam-switching problems attendant with the high cycling rate are discussed.

Methods of cyclotron beam development and diagnostics are described. Techniques for measuring the space, time and energy distributions of both internal and external beams are included. Emphasis is on the more recent methods commonly used at many laboratories.