Engineering topics

Jurak, A.

Publications and source records attributed to Jurak, A..

9 records

NASA NTRS1986

Average transverse momentum and energy density in high-energy nucleus-nucleus collisions

Emulsion chambers were used to measure the transverse momenta of photons or pi(0) mesons produced in high-energy cosmic-ray nucleus-nucleus collisions. A group of events having large average transverse momenta has been found which apparently exceeds the expected limiting values. Analysis of the events at early interaction times, of the order of 1 fm/c, indicates that the observed transverse momentum increases with both rapidity density and energy density.

Burnett, T. H.↗

NASA NTRS1985

Nucleon-nucleus interactions from JACEE

Results on hadron-nucleus interactions from the Japanese-American Cooperation Emulsion Experiment experiment are presented. Angular distributions for charged particles, and angular and transverse momentum spectra for photons have been measured for a sample of events with sigma epsilon sub gamma. Results on central rapidity density and transverse energy flow are discussed.

Burnett, T. H.↗

NASA NTRS1985

Heavy nucleus collisions between 20 and 60 GeV/nucleon

Interest in studying relativistic nucleus-nucleus interations arises from the fact that they offer an opportunity to probe nuclear matter at high density and temperature. It is expected that under such extreme conditions a transition from hadronic matter into quark-gluon plasma occurs and that in the interactions of highly relativistic nuclei such conditions are created. Cosmic rays remain a unique source of high energy heavy nuclei. The Japanese-American Cooperative Emulsion Experiment (JACEE-3) was designed to study the collisions of heavy cosmic ray nuclei with different nuclear targets at energies beyond 20 GeV/nucleon. JACEE-3 experiment was carried out using a combined electronic counters and an emulsion chamber detector, which was exposed to the cosmic rays on a balloon at an altitude of 5 g/sq cm.

Burnett, T. H.↗

NASA NTRS1985

Nucleus-nucleus interaction above several hundred GeV/n

The Japanese-American Cooperative Emulsion Experiment (JACEE) have been investigating high energy nuclear interactions of cosmic ray nuclei by means of balloon-borne emulsion chamber. Current exposure parameters are listed. Analysis of the last two experiments (JACEE4 and JACEE5) are still in progress. A result of semi-inclusive analysis of a sample set of central collision events is presented here, concerning multiplicity, rapidity fluctuation for extremely high multiplicity events and correlation between transverse momentum and estimated energy density.

Burnett, T. H.↗

NASA NTRS1985

Observation of direct hadronic pairs in nucleus-nucleus collisions in JACEE emulsion chambers

In a number of high energy ( or = 1 TeV/amu) nucleus-nucleus collisions observed in Japanese-American Cooperative Emulsion Experiment (JACEE) emulsion chambers, nonrandom spatial association of produced charged particles, mostly hadronic pairs, are observed. Similar narrow pairs are observed in about 100 events at much low energy (20 to 60 GeV/amu). Analysis shows that 30 to 50% of Pair abundances are understood by the Hambury-Brown-Twiss effect, and the remainder seems to require other explanations.

Burnett, T. H.↗

NASA NTRS1985

Excessive production of electron pairs by soft photons in low multiplicity ion interactions

Three multiply charged primary cosmic ray interactions with carbon nuclei are reported, in which the number of materialized electron pairs within a distance of about 0.3 conversion length is larger than predicted from isospin considerations. These are the most energetic (sigma E gamma 4 TeV) of the low multiplicity ( 15 tracks) events observed in the Japanese-American Cooperative Experiment (JACEE-2) emulsion chamber.

Burnett, T. H.↗

NASA NTRS1983

Extremely high multiplicities in high-energy nucleus-nucleus collisions

Two unusually-high-multiplicity interactions of high-energy heavy nuclei were observed in a balloon-borne emulsion chamber: an Si(+)AgBr event (4 TeV/nucleon) and a Ca(+)C event (100 TeV/nucleon), with 1015 and 760 charged particles, respectively. The multiplicities and rapidity distributions favor the multichain model but not the wounded-nucleon superposition model. The high average transverse momentum (550-700 MeV/c) and the rapid fluctuations of the events are not readily understood in terms of any superposition models.

Burnett, T. H.↗

NASA NTRS1982

Primary proton and helium spectra in the energy range 10 to the 12th to 10 to the 14th eV

Measurements of proton and helium spectra have been made in the energy range 10 to the 12th to 10 to the 14th eV. Large area thin emulsion calorimeters were used in the Japanese American Cooperative Emulsion Experiment balloon flight series. Power indices of the integral spectra for both nuclei are consistent with published data at lower energies. Absolute intensities are also consistent for helium and proton fluxes with extrapolations of previous data. No steepening of the proton spectrum is indicated.

Gregory, J. C.↗

NASA NTRS1981

Japanese-American Cooperative Emulsion Experiment /JACEE/

The instrumentation and results of long duration balloon flights carried out jointly by U.S. and Japan researchers to examine high energy cosmic rays are reported. Basic detector geometries are 2.5 sq m sr with operation at altitudes with 3-4 g/sq cm pressure, with observations thus far of over 100 hr. Energies from 2-100 TeV are recorded for nucleus-nucleus and hadron-nucleus interactions, and searches are made for new particle or interactions. The detector is an emulsion chamber which comprises doubly-coated nuclear emulsions on 800 micron thick methacryl substrates, X-ray films, etchable detectors, low density spacers, and lead sheets. Segmentation of the instrument into a primary charge module, a target section, a spacer section, and a lead-emulsion calorimeter allows accurate charge measurement for primary nuclei, reliable energy resolution, and a large geometrical factor for collecting high energy events. A primary Ca nucleus of 300 TeV has been observed.

Huggett, R. W.↗