D. E. Greiner

HIGH RESOLUTION SPECTROMETRY FOR RELATIVISTIC HEAVY IONS

Abstract Several techniques are discussed for velocity and energy spectrometry of relativistic heavy ions with good resolution. A foil telescope with chevron channel plate detectors is described. A test of this telescope was performed using 2.1 GeV/A C 6+ ions, and a time-of-flight resolution of 160 ps was measured. Qualitative information on the effect of foil thickness was also obtained.

A versatile, high-resolution particle identifier-theory☆

Abstract A method of measurement and analysis is presented which makes maximum use of the dependence of energy loss d E d x upon range to identify isotopically particles which stop in an identifier consisting of several thick, solid state detectors. Theoretical identification efficiency, mass resolution, charge resolution, and energy resolution are determined. A following paper provides experimental resolutions and describes two identifiers; one used to provide particle identification during heavy ion fragmentation studies at the Bevatron, Lawrence Berkeley Laboratory; the other, a rocket-borne instrument used to measure the isotopic abundances in the inner trapped radiation belt.

Electromagnetic dissociation of relativistic O18 nuclei

Measurements of fragment-production cross sections have been made with 0 projectiles of 1.7 GeV/nucleon incident upon targets of Be, C, Al, Ti, Cu, Sn, W, Pb, and U at the LBL Bevalac. We have found that the enhancement with high-Z targets of cross sections for certain fragments agrees both in magnitude and ZT dependence with the predictions of the electromagnetic-dissociation process, which are based upon the known photonuclear cross sections and classical rel?tivistic virtual-photon theory. We have found as well that factorization of the cross sections for nuclear processes is valid to an accuracy of better than 4~. *This work was supported by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the u.s. Department of Energy under Contract W-7405-ENG-48. This manuscript was printed from originals provided by the author.

A multiple sampling ionization chamber (MUSIC) for measuring the charge of relativistic heavy ions

A large area (1 m × 2 m) multiple sampling ionization chamber (MUSIC) has been constructed and tested. The MUSIC detector makes multiple measurements of energy “loss”, dE/dx, for a relativistic heavy ion. Given the velocity, the charge of the ion can be extracted from the energy loss distributions. The widths of the distributions we observe are much narrower than predicted by Vavilovs theory for energy loss while agreeing well with the theory of Badhwar which deals with the energy deposited. The versatile design of MUSIC allows a variety of anode configurations which results in a large dynamic range of charge. In our tests to date we have observed charge resolutions of 0.25e fwhm for 727 MeV/nucleon 40A and 0.30e fwhm for 1.08 GeV/nucleon 139La and 139La fragments. Vertical position and multiple track determination are obtained by using time projection chamber electronics. Preliminary tests indicate that the position resolution is also very good with α ≅ 100 μm.

Fragmentation of Nitrogen-14 Nuclei at 2.1 Gev per Nucleon

An experiment has been carried out at the bevatron on the nuclear fragmentation of nitrogen-14 ions at an energy of 2.1 billion electron volts (Gev) per nucleon. Because of the near equality of the velocities of the nitrogen-14 beam and the fragmentation products at an angle of 0�, we find it possible to identify the nuclear fragments isotopically.

Charge changing cross sections of relativistic uranium

We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U/sup 92 +/ reversible U/sup 91 +/ and U/sup 91 +/ reversible U/sup 90 +/ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx. = 5% bare U/sup 92 +/ at 200 MeV/nucleon and 85% U/sup 92 +/ at 962 MeV/nucleon. 7 references, 5 figures.

The HISS spectrometer at the bevalac

Abstract The status of the HISS spectrometer is presented. Preliminary data from multi-particle measurements of the 12 C reactions at 1 GeV/n are discussed.

A quasi-exclusive measurement of 12C(12C, 3α)X at 2.1 GeV/nucleon

Abstract A study of the reaction 12 C( 12 C, 3α)X at 2.1 GeV/nucleon has been completed. The energy and momentum transferred to the 12 C projectile and the cross section for the dissociation of 12 C into three alpha particles have been measured, 9.7 (+5.0/ −2.5) millibarns. It is found that the results from this analysis are inconsistent with the predictions of current theoretical models for peripheral relativistic heavy ion collisions.

A facility for calibrations and short experiments with heavy ions at the Bevatron

Abstract Heavy-ion beams at the Lawrence Berkeley Laboratory Bevatron are routinely available for calibration purposes. These beams are very useful to cosmic-ray physicists and others who wish to have empirical evidence indicating their instruments really can identify elements or isotopes. Virtually all isotopes through 16 O can be produced over a wide energy range.

Electromagnetic dissociation of relativistic O-18 nuclei

Measurements of fragment-production cross sections have been made with 0 projectiles of 1.7 GeV/nucleon incident upon targets of Be, C, Al, Ti, Cu, Sn, W, Pb, and U at the LBL Bevalac. We have found that the enhancement with high-Z targets of cross sections for certain fragments agrees both in magnitude and ZT dependence with the predictions of the electromagnetic-dissociation process, which are based upon the known photonuclear cross sections and classical rel?tivistic virtual-photon theory. We have found as well that factorization of the cross sections for nuclear processes is valid to an accuracy of better than 4~. *This work was supported by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the u.s. Department of Energy under Contract W-7405-ENG-48. This manuscript was printed from originals provided by the author.