The single particle inclusive reactions "C + ' C~x + anything (3 (Z & 6) have been studied at 250 MeV/nucleon at nine production angles from 0' to 4'. Production cross sections for most isotopes (Z& 2) were determined. The longitudinal and transverse momentum distributions were constructed. The results at this energy are compared to the data at other energies and to the model of Friedman. It appears that, after the Coulomb effects are separated, there is very little energy dependence in the fragmentation process.

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Yields of neutron-rich projectile fragments have been measured at 0° for the reaction of 212-MeV/amu 48 Ca ions on an 890-mg-cnT 2 beryllium target. Fourteen nuclides have been observed for the first time. The systematics of production cross sections are discussed.The limits of stability for nuclei have been established up to sodium and beryllium for protonrich and neutron-rich nuclides, respectively. Recently, the techniques of relativistic heavy-ion fragmentation, 1 deeply inelastic scattering, 2 and spallation induced by high-energy protons 3 have been used to produce neutron-rich nuclei near the limit of particle stability. In this Letter, we present the first experimental evidence for the particle stability of fourteen nuclides, 22 N, 26 F, 33,34 Mg> 36,37 A1> 38,39^ 41,42 p> 43,44^ and 44,45 Cl, produced in the fragmentation of 212-MeV/amu 48 Ca. In addition, the recent observation 2 of 37 Si, 40 P, and 41 ' 42 s is confirmed. Predictions for the masses of neutron-rich light nuclei have been made based on several methods, including iterative techniques such as the modified GarveyKelson relations, 4,5 the liquid-droplet model, 6,7 and large-basis shell-model calculations. 8 The energy levels of such nuclei have also been predicted using the same shell-model calculations. 8 ' 9 From the present experiment it appears that the production cross sections for very neutron-rich light nuclei may be quite sensitive to their detailed nuclear structure.The experimental arrangement used for the present work was similar to that described in Ref. 1. The fragments, which emerge from the reaction at nearly the beam velocity, were detected in a zero-degree magnetic spectrometer with an acceptance of 0.94 msr. A detector telescope consisting of twelve Si(Li) detectors, two position-sensitive Si(Li) detectors (PSD), and a veto scintillator was placed in the focal plane of the spectrometer. Each of the twelve Si(Li) detectors was 5 mm thick and 5 cm in diameter while the PSD's were 500 /xm thick and 6 cm in diameter. The PSD's were arranged to measure horizontal and vertical position with a resolution of ~ 1 mm. The beam current of 48 Ca ions from the Bevalac was ~10 7 particles/sec and was monitored directly with plastic scintillators, an ion chamber, and a scintillator telescope that monitored particles scattered from the target. The target consisted of 890 mg cm" 2 of beryllium and the beam lost approximately 35 MeV/amu passing through it.Combining the spectrometry with the energyloss measurements in the Si(Li) detectors made it possible to measure M and Z unambiguously as described in Ref. 1. The mass resolution obtained was 0.3 amu. The mass-and atomic-number scales were calibrated by use of the direct 48 Ca beam and also beams of 20 Ne and ^Ar of high energy that were progressively degraded to provide a continuous spectrum of 20 Ne and 40 Ar ions stopping in each detector. Since the detector thicknesses were precisely known, it was then possible to use a range-energy table to make an accurate channel-to-energy calibratio...

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Hasxeldine and K i d d .290 1PerJluoroalEyl Berimtiurn of Sulphur. Part II.* Trijuoromethanesulphonic, -sulphinic, and -sulphenic Acid and th.e Infrared Spectra of Compounds Containing -SO,and > S O Groups.

Haszeldiqze and K i d d .

We have identified cosmic rays with Z = 40, 44, 52, 71, 77, 78, and 92 slowing in a balloon-borne stack. The values of Z assigned by both Lexan plastic detectors and nuclear emulsions were the same to within two units. Both low-and high-energy heavy cosmic rays are synthesized in the rapid neutron-capture process.We have found that nuclei with Z up to 92 are present in the low-energy cosmic radiation. Their abundance relative to Fe is similar to that previously observed at energies above ~1 GeV/ amu. 1,2 From their large rate of change of ionization as they slow down in a detector, their atomic number and energy can be much better determined than if they were relativistic. These observations are important as a basis for understanding the origin and propagation of the cosmic rays and as a standard of comparison with results obtained from the analysis of tracks of ancient cosmic rays left in meteorites 3 and moon rocks. 4

Tracks of 99 nuclei with 2 > 3 6 have been analyzed in a stack of Lexan polycarbonate, cellulose triacetate, and nuclear emulsion launched from Palestine, Texas, with an area-time factor of 900 m2 h. Although the mean deviation in charge assignment between plastics and emulsion was -3 units, there was no systematic variation. One nucleus with charge estimated to be 2-96 (p=0.95) was identified in all three detectors. Combining all available data, 33 events have been found with 2>70, giving for the important ratio (2>83)/ ( 7 0 5 2 5 8 3 ) the value -0.3. The weakness of the Pb peak relative to the Pt peak indicates that little radioactive decay of the transbismuth nuclei has occurred. These results favor supernova explosions within the galaxy as the major source of cosmic rays and suggest that their average lifetime is less than lo7 yr.