In neutron dosimetry, calculations enable one to predict the response of a proposed dosimeter before effort is expended to design and fabricate the neutron instrument or dosimeter. The nature of these calculations requires the use of computer programs that implement mathematical models representing the transport of radiation through attenuating media. Numerical, and in some cases analytical, solutions of these models can be obtained by one of several calculational techniques. All of these techniques are either approximate solutions to the well-known Boltzmann equation or are based on kernels obtained from solutions to the equation. The Boltzmann equation is a precise mathematical description of neutron behavior in terms of position, energy, direction, and time. The solution of the transport equation represents the average value of the particle flux density. Integral forms of the transport equation are generally regarded as the formal basis for the Monte Carlo method, the results of which can in principle be made to approach the exact solution. This paper focuses on the Monte Carlo technique.

We have investigated the role of an isomeric state and its coupling to the ground state (g.s.) via photons and neutron inelastic scattering in a stellar environment by making detailed photonuclear and neutron cross-section calculations for /sup 176/Lu and /sup 210/Bi. In the case of /sup 176/Lu, the g.s. would function as an excellent galactic slow- (s-) process chronometer were it not for the 3.7-h isomer at 123 keV. Our calculations predicted much larger photon cross sections for production of the isomer, as well as a lower threshold, than had been assumed based on earlier measurements. These two factors combine to indicate that an enormous correction, a factor of 10/sup 7/, must be applied to shorten the current estimate of the half-life against photoexcitation of /sup 176/Lu as a function of temperature. This severely limits the use of /sup 176/Lu as a stellar chronometer and indicates a significantly lower temperature at which the two states reach thermal equilibrium. For /sup 210/Bi, our preliminary calculations of the production and destruction of the 3 /times/ 10/sup 6/ y isomeric state by neutrons and photons suggest that the /sup 210/Bi isomer may not be destroyed by photons as rapidly as assumed in certain …

An analytical procedure was developed to estimate the cooldown time between pulses of the Compact Ignition Tokamak (CIT) utilizing liquid nitrogen. Fairly good agreement was obtained between the analysis results and those measured in the early fusion experimental devices. The cooldown time between pulses in the CIT is controlled by the energy disposition in the inner leg of the TF coil. A cooldown time of less than one hour is feasible for the CIT if fins are used in the cooling channels. An R and D experimental program is proposed to determine the actual cooldown time between pulses since this would be considered an issue in the conceptual design of the CIT.

Data from e/sup +/e/sup -/ annihilations at 29 GeV have been used to measure the production and fragmentation of eta mesons. The signal is observed in the eta ..-->.. ..gamma gamma.. decay channel. The fragmentation function for p/sub eta/ > 1.5 GeV/c agrees well with the shapes predicted by both the Lund and Webber models. However, the mean multiplicity is measured to be < n/sub eta/ > = 0.37 +- 0.08 eta mesons per hadronic annihilation event, which is significantly lower than the values predicted by either model. 6 refs., 2 figs., 1 tab.

The report consists of viewgraphs. Topics covered are (1) basic ripple processes, (2) simulations of combined processes, (3) modeling issues, (4) new physics problems, and (5) consequences for ETR/ITER. (WRF)

The interferometer and viewing optics that are the main optical components of an Automated Surface Mapping system (ASM) used to characterize the surface topography and the wall thickness uniformity of opaque and transparent spherical shells is described. To characterize surface finish or wall thickness of spherical shells with an accuracy of 10 nm and a resolution of 1 ..mu..m the differential phase shift between two beams of orthogonal polarizations is measured, before and after the probe beam has interacted with the test object.

Over the years the study of the confinement of high temperature plasma in magnetic mirror systems has presented researchers with many unusual physics problems. Many of these issues are by now understood theoretically and documented experimentally. With the advent of the tandem mirror idea, some new issues have emerged and are now under intensive study. These include: (1) the generation and control of ambipolar confining potentials and their effect on axial confinement and, (2) the combined influence of nonaxisymmetric magnetic fields (used to ensure MHD stability) and electric magnetic particle drifts on radial transport. Physics considerations associated with these two categories of issues will be reviewed, including concepts for the control of radial transport, under study or proposed.

A new electric gun system was constructed for use in high-pressure EOS studies. The system is powered by a 100 kV, 15.6 ..mu..F capacitor bank. At 100 kV charging voltage the system inductance is 23 nH. This system has driven 0.3 mm-thick Kapton projectiles to > 20 km/s and 0.3 mm Kapton/30 ..mu..m Ta projectiles to approx. 10 km/s. Projectile velocity is modeled phenomenlogically by an electrical Gurney model.

The rates for a number of reactions producing certain stable nuclides, such as /sup 3/He and /sup 4/He, and fission in the moon are calculated for galactic-cosmic-ray particles and for solar protons. Solar-proton-induced reactions with bromine usually are not an important source of cosmogenic Kr isotopes. The /sup 130/Ba(n,p) reaction cannot account for the undercalculation of /sup 130/Xe production rates. Calculated production rates of /sup 15/N, /sup 13/C, and /sup 2/H agree fairly well with rates inferred from measured excesses of these isotopes in samples with long exposure ages. Cosmic-ray-induced fission of U and Th can produce significant amounts of fission tracks and of /sup 86/Kr, /sup 134/Xe, and /sup 136/Xe, especially in samples with long exposures to cosmic-ray particles.

Recent developments in high reliability components for linear induction accelerators (LIA) make possible the use of LIAs as large-scale, economical sources of radio-frequency (rf) power for many applications. One particularly attractive example of interest to high energy physicists is a ''two-beam accelerator'' version of a linear e/sup +/-e/sup -/ collider at TeV energies in which the LIA is configured as a monolithic relativistic klystron operating at 10 to 12 GHz. Another example of keen interest to the fusion community is the use of the LIA to drive a free-electron laser operating at 200 to 500 GHz for use in heating fusion plasma via electron resonance cyclotron heating. This paper briefly describes several potential uses of LIA radiation sources. It discusses the physical basis for scaling our present experience with LIAs to the operating characteristics applicable to large-scale sources of rf power and synchrotron radiation. 14 refs., 6 figs., 1 tab.

The focus is on electric power production using geothermal resources greater than 150/sup 0/C because this form of geothermal energy utilization has the most serious health-related consequences. Based on measurements and experience at existing geothermal power plants, atmospheric emissions of noncondensing gases such as hydrogen sulfide and benzene pose the greatest hazards to public health. Surface and ground waters contaminated by discharges of spent geothermal fluids constitute another health hazard. It is shown that hydrogen sulfide emissions from most geothermal power plants are apt to cause odor annoyances among members of the exposed public - some of whom can detect this gas at concentrations as low as 0.002 parts per million by volume. A risk assessment model is used to estimate the lifetime risk of incurring leukemia from atmospheric benzene caused by 2000 MW(e) of geothermal development in California's Imperial Valley. The risk of skin cancer due to the ingestion of river water in New Zealand that is contaminated by waste geothermal fluids containing arsenic is also assessed. Finally, data on the occurrence of occupational disease in the geothermal industry are summarized briefly.

This article discusses rapid idothermal annealing of As-, P-, and B-implanted silicon.

Absorption spectra obtained from SmBr/sub 3/, SmBr/sub 2/, and Sm0Br were used in identifying the samarium species in several mixed-valence Sm(II/III) compounds produced by H/sub 2/ reduction of SmBr/sub 3/. The nature of the absorption of Sm0Br made it possible to detect even traces of Sm0Br in the Sm bromides.