Engineering topics

Lord, J. J.

Publications and source records attributed to Lord, J. J..

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

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 NTRS1983

An instrument employing electronic counters and an emulsion chamber for studying heavy cosmic ray interactions (JACEE-3)

A JACEE-3 instrument was flown on a balloon in June 1982 for 6.1 sq m sr hr exposure at an average atmospheric depth of 5 gm/sq cm in order to study the cosmic ray spectra, composition, and interactions above 1 TeV. The nucleus-nucleus interactions were studied above 20 GeV/amu from z = 6 to z = 26. The electronic counters contained gas Cerenkov structures with a 1.0-cm thick lead glass and a 1.27-cm thick Teflon radiator. A comparison to the instrument prototype is made. Based on the electronic counter event data, the finding efficiency of the hodoscope is noted to be near 100 percent for z greater than or equal to 22. A comparison is made between the hodoscope-predicted position and track found at P3 in an emulsion chamber.

Austin, R. W.↗

NASA NTRS1983

Measurement of heavy cosmic rays above 20 GeV/n in passive detectors - Preliminary results from JACEE-3

It is pointed out that the JACEE-3 experiment combined electronic counters and an emulsion chamber to study nucleus-nucleus interactions between 20 and 100 GeV/n. In the present paper, a description is given of the use of the passive detector stack. The electronic position detectors facilitate the event location, taking into account a determination of the incident angles. CR-39 plastic plates were placed just below the proportional counters to enhance tracking accuracy. The JACEE-3 emulsion chamber consists of three parts, including the charge module, the target module, and the calorimeter module. The charge module is mainly used in track identification. The obtained results are also discussed, giving attention to event number and tracking efficiency, interaction measurements, and the inelasticity distribution.

Burnett, T. H.↗

NASA NTRS1978

High energy primary electron spectrum observed by the emulsion chamber

A detector of the emulsion chamber type is used to measure the energy spectrum of cosmic-ray electrons. Two large emulsion chambers, each having an area of 40 by 50 sq cm, are exposed for about 25.5 hr at an average pressure altitude of 3.9 mbar. About 500 high-energy cascades (no less than about 600 GeV) are detected by searching for dark spots on the X-ray films. A power-law energy dependence formula is derived for the spectrum of primary cosmic-ray electrons in the energy region over 100 GeV. The results are in good agreement with the transition curves obtained previously by theoretical and Monte Carlo calculations.

Nishimura, J.↗