Several tissue-equivalent human-torso phantoms have been constructed for the calibration of counting systems used for in-vivo measurement of transuranic radionuclides. The phantoms contain a simulated human rib cage (in some cases, real bone) and removable model organs, and they include tissue-equivalent chest plates that can be placed over the torso to simulate people with a wide range of statures. The organs included are the lungs, liver, and tracheobronchial lymph nodes. Polyurethane with varying concentrations of added calcium was used to simulate the linear photon-attenuation properties of various human tissues, including lean muscle, adipose-muscle mixtures, cartilage, and bone. Foamed polyurethane was used to simulate lung tissue. Organs have been loaded with highly pure /sup 238/Pu, /sup 239/Pu, /sup 241/Am, and other radionuclides of interest. The validity of the phantom as a calibration standard has been checked in separate intercomparison studies using human subjects whose lungs contained a plutonium simulant. The resulting phantom calibration factors generally compared to within +-20% of the average calibration factors obtained for the human subjects.

To detect conditions and to forestall events in which an electron or positron beam might otherwise melt a hole in its SLC arc vacuum chamber, and to provide information on the magnitude and location of these and other, less harmful, beam losses, it is planned to install two PLIC cables along each arc, one on each side of the magnet string. A similar system (but with one long ion chamber) has been in use at SLAC for 20 years. Electromagnetic shower calculations have been made to estimate the ion chamber signals which will be produced in the new system, making use of data from the old system. It is estimated that a potentially damaging beam loss in an SLC arc will give rise to an ion chamber signal pulse with an amplitude on the order of 2 to 5 volts. Depending upon the location of a beam loss, sensitivity may vary from its average value by as much as 40%. Most of this signal is due to charged particles in the electromagnetic shower that are able to escape the magnetic field and reach PLIC.

The changes in the sensitivity (S) and the equivalent X-ray limit (P/sub x/) of several Bayard-Alpert gauges (BAGs) were studied when the size of the collectors was reduced from 125 ..mu.. to 50 ..mu.. and when different mounting envelopes were used. Based on this study, 400 custom BAGs with 50 ..mu.. collector were purchased from a vendor. The S and the P/sub x/ of these thin-collector BAGs were also measured.

This report discusses the progress made on laser particle acceleration. First a brief discussion of the collaboration with the University of California at Santa Barbara to examine the technical trade-offs involved in the choice of an inverse Cerenkov (IC) demonstration experiment. The goals of the IC demonstration experiment are to show the applicability of the IC mechanism to electron beam focusing and acceleration. The second part of this report covers glancing incidence measurements of mirrors. The work being performed centers around the issue of dielectric overcoats on metal mirrors. In any type of laser particle accelerator careful consideration of the timing, phasing, and alignment between laser and particle beams must be incorporated in a complete system study. Analysis of these problems has been initiated and a survey of preliminary results are covered in the last part of this report. During this year, Spectra Technology Inc. (STI) has collaborated with Prof. Jorge Fontana, of the University of California, Santa Barbara (UCSB), to examine the technical trade-offs involved in the choice of an inverse Cerenkov (IC) demonstration experiment. Prof. Fontana`s responsibilities have been to address the rationale and requirements for the demonstration experiment, including an evaluation and selection of the most attractive …

Some examples of nuclear data in which the uncertainty has been underestimated, or at least appears to be underestimated, are reviewed. The subjective aspect of the problem of systematic uncertainties is discussed. Historical aspects of the data uncertainty problem are noted. 64 refs., 6 tabs.

We review the theory of the Mikheyev-Smirnov-Wolfenstein effect, in which matter oscillations can greatly enhance ''in vacuo'' neutrino oscillations, and we examine its consequences for the solar neutrino problem. Using a two-flavor model, we discuss the solutions in the ..delta..m/sup 2/-sin/sup 2/2THETA parameter space for the /sup 37/Cl experiment, and describe their predictions for the /sup 71/Ga experiment and for the spectrum of electron-neutrinos arriving at earth. We also comment on the three-flavor case.

Effects of Linac transverse wakefields are combined with residual eta and partially compressed bunches (presently the SLC design) to place much tighter, current dependent limits on residual eta and eta'. The limits are comparable to or exceed those needed at the SLC final focus. These limits will be difficult to maintain due to present experimental resolution.