A computer code was written to describe the alpha particle energy loss. The problem of a symmetric compression of the DT gas by an exploding microsphere is analyzed. The code calculates the energy spectrum of a Gaussian distribution of alpha particles after passing through the compressed gas and the exploded glass. The calculations are being used to determine design parameters for diagnostic instruments for measuring charged particle energy distributions from laser fusion targets. (MOW)

This paper discusses a series of experiments performed with the LLL two-beam laser system, JANUS. The JANUS laser is capable of focusing approximately 500 Gigawatts of 1.06 ..mu.. power (40 J in 80 psec) on laser fusion type targets. In these experiments, the targets were deuterium tritium (DT) filled glass microshells with aspect ratios of 100 to 200. Targets of this type operate in what is commonly called the exploding pusher mode. The result is that the glass shell surrounding the DT gas (the thermonuclear fuel) effectively explodes, and consequently from geometry, also implodes and compresses and heats the DT gas to TN conditions. The advantages and disadvantages of the exploding pushers type target, as compared with the high density isentropic implosion target of the future, is illustrated.

A spectrometer has been developed for measuring the charged particle production cross sections and spectra in neutron-induced reactions. The spectrometer consists of a magnetic quadrupole doublet which focuses the charged particles onto a silicon surface barrier detector telescope which is 2 meters or more from the irradiated sample. Collimators, shielding, and the large source-to- detector distance reduce the background enough to use the spectrometer with a 14- MeV neutron source producing 4 . 10$sup 12$ n/s. The spectrometer has been used in investigations of proton, deuteron, and alpha particle production by 14-MeV neutrons incident on various materials. Protons with energies as low as 1.1 MeV have been measured. The good resolution of the detectors has also made possible an improved measurement of the neutron- neutron scattering length from the 0$sup 0$ proton spectrum from deuteron breakup by 14-MeV neutrons. (auth)

In spite of the remarkable safety record of the nuclear industry as a whole, recent public concern over the potential impact of the industry's accelerated growth has prompted ERDA to expand its emergency response procedures. The Atmospheric Release Advisory Capability, ARAC, is a computer communications system designed to enhance the existing emergency response capability of ERDA nuclear facilities. ARAC will add at least two new functions to this capability: centralized, real-time data acquisition and storage, and simulation of the long range atmospheric transport of hazardous materials. To perform these functions, ARAC employs four major sub-systems or facilities: the site facility, the central facility, the global weather center and the regional model. The system has been under development for the past two years at the Lawrence Livermore Laboratory of the University of California. (auth)

Computer calculations of the interaction of a 1.06 $mu$m laser pulse with a spherical DT-filled glass shell embedded in low density foam are compared with experimental results. Poor coupling of the absorbed energy to the spherical capsule was observed, resulting in a barely detectable neutron signal. The x-ray micrograph shows that the electron conduction in the target was strongly inhibited. Calculational results are presented that indicate the inhibited electron conduction may be the result of large spontaneously-generated magnetic fields. Calculations including the magnetic field are seen to agree reasonably well with the experiment. (auth)

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Parylene disks supported on glass stalks were irradiated with 1.06 $mu$m wavelength laser light pulses focused to flux intensities in the range from 10$sup 15$ to 10$sup 17$ W/cm$sup 2$. According to photodiode measurements the fraction of laser light absorbed, 25 to 50 percent, increased slightly as the laser intensity was increased. However, box calorimeter measurements implied that the fraction absorbed was approximately 30 percent and insensitive to irradiation intensity. Some x-ray spectra are discussed. (MOW)

An instrument is described which is designed to determine radioactive isotope spectra in the field under adverse environmental conditions. The instrument is battery-powered, stores and compares multiple spectra, and performs computations upon the resulting displayed graph. (auth)

Use of double shell targets with a separate low Z, low density ablator at large radius for the outer shell, reduces the focusing and power requirements while maintaining reasonable aspect ratios. A high Z, high density pusher shell is placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. Ion beams appear to be a promising power source and breakeven at 10-20 Terrawatts with 10 MeV alpha particles appears feasible. Predicted performance of targets with various energy sources is shown and comparison is made with single shell targets. (auth)

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A 4.2- to 300-K liquid helium cryostat was constructed for cryogenic samples of D-T containing up to 4 x 10$sup 14$ dis/s (10,000 Ci) of tritium radioactivity. The cryostat is enclosed in a secondary box, which acts as the ultimate container in case of a tritium release. Dry argon is flushed through the box, and the box atmosphere is monitored for tritium, oxygen, and water vapor. A rupture disk and abort tank protect the box atmosphere in case the sample cell breaks. If tritium breaks into the box, a powdered uranium getter trap reduces the 4 x 10$sup 14$ dis/s (10,000 Ci) to 4 x 10$sup 9$ dis/s (0.1 Ci) in 24 h. A backup palladium-zeolite getter system goes into operation if an overabundance of oxygen contaminates the uranium getter. (auth)

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