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At least 883 records · Page 49

The primary cosmic ray electron spectrum from 10 GeV to about 200 GeV

An ionization spectrometer consisting of 10.8 radiation lengths of tungsten and 35 radiation lengths of iron has been used to determine the energy spectrum of cosmic ray electrons above 10 GeV. The spectrometer was calibrated with electrons from 5.4 to 18 GeV and then flown at an altitude of 6 gm-cm/2 for 16 hours. Separation of electron initiated events from proton events was achieved by utilizing starting point distributions, the shower development in tungsten, and the energy deposited in the large thickness of iron absorber. The exponent of the differential energy spectrum of the electrons is -3.1 + or - 0.2 while the exponent of the background is consistent with the proton exponent of -2.7 + or -0.2.

Silverberg, R. F.↗

Interplanetary dust and comet orbits

Several years of observational results are available from the Pioneer 8 and 9 interplanetary dust detectors, and these data were used to show dust counts graphically. The characteristics of the five largest dust showers are also summarized.

Roosen, R. G.↗

Origin of cosmic electrons from about 100 to 1,000,000 GeV.

The origin of high-energy cosmic electrons is considered. It is found that electrons of energies below 1000 GeV could have been produced by local supernovae associated with known radio remnants. At higher energies, observations of muon-poor air showers indicate the existence of electrons at 1,000,000 GeV which may have originated entirely from the supernova Vela X.

Ramaty, R.↗

Origin and composition of ultrahigh energy cosmic rays.

Suggestion that, under certain circumstances, the absence of an apparent flattening of the ultrahigh energy cosmic ray spectrum at an energy level above 3 x 10 to the 18th power eV may have implications concerning the origin of ultrahigh energy cosmic rays (UECR). On the basis of the discussion presented, it seems that a heavy composition is indicated. It is therefore concluded that recent air-shower studies seem to indicate the resurrection of the galactic origin model.

Stecker, F. W.↗

The energy spectrum of primary cosmic ray electrons from 2 GeV to 200 GeV.

Use of a balloon-borne counter telescope with a gas Cerenkov counter to measure the energy of primary cosmic ray electrons between 2 and 200 GeV. Electrons are identified by the characteristic electron-photon shower which they produce in a 15 radiation length deep stack of high-Z material interleaved with scintillation counters. Calibrations with monoenergetic electrons up to 14 GeV and monoenergetic protons up to 28 GeV from accelerators are used to develop criteria to statistically separate electrons from proton-induced events. The results from six balloon flights (total exposure time 63 hours) are combined to obtain the electron energy spectrum. Up to about 30 GeV, the spectrum measured in this experiment can be directly checked with calibrations and agrees well with results from other experiments. Above this energy, the flux reported in the present work is somewhat higher than the determinations reported by most other authors. An apparent flattening of the energy spectrum above 50 GeV is not regarded as significant. There is no evidence for a steepening of the spectrum at energies below 200 GeV.

Fanselow, J. L.↗

Reality of Comet Nucleus

The structure of the cometary nucleus is discussed. The view that the comet is a vast swarm of tiny particles separated by large distances is defended by the argument that during the meteor showers of 1966, the earth intercepted thousands of millions of meteoric particles; however, no reports of a single meteorite reaching the ground were recorded. Another feature that indicates that a comet consists of a swarm of particles is that the comets contract as they approach the sun, and expand again as they recede.

Lyttleton, R. A.↗

Evidence from Stream Meteoroids

The physical behavior and composition of shower meteors were examined in an effort to establish the structure of its parent comet. Properties considered include degree of fragmentation and density.

Mccrosky, R. E.↗

Comet Encke: Meteor metallic ion identification by mass spectrometer

Metal ions including Na-40(+), Mg-24(+), Si-28(+), K-39(+), Ca-40(+), Sc-45(+), Cr-52(+), Fe-56(+), and Ni-58(+) were detected in the upper atmosphere during the beta Taurids meteor shower. Abundances of these ions relative to Si(+) show agreement in most instances with chondrites. A notable exception is 45(+), which is Sc(+), is 100 times more abundant than neutral scandium found in chondrites.

Goldberg, R. A.↗

Personal hygienic concerns in long term space flight

Data from numerous experiments and hardware inventories were scanned for Skylab personal hygiene use. A computer program was formulated for predicting the degree of man's involvement with personal hygiene needs. A tabulation was kept for such events as water intake, frequency of urination and defecation, accidents or events requiring clean-up, methods of clean-up, microbiological environment and shower water contamination.

Source record↗

Progress in the measurement of high-energy galactic cosmic ray electrons

Cosmic ray electron measurements by individual threshold detector elements show that about 30 percent of observed electron-like galactic cosmic showers are really proton initiated events. The cosmic electron spectrum at about 10 GeV exhibits a consistent dropoff in intensity leading to a best fit at a power law of spectral index -3.2; a break in the spectrum should occur above 10 GeV.

Silverberg, R. F.↗

Reality of comet nucleus.

The prime problem of a comet mission must be to settle whether the cometary nucleus has an actual tangible material existence, or whether it arises from some optical effect present only at times within comets. The absence of any large particles in a comet seems to be demonstrated by certain meteor showers. A feature that would seem to indicate that a comet consists primarily of a swarm of particles is that the coma in general contracts as the comet approaches the sun, roughly in proportion within the distance, and then expands again as it recedes.

Lyttleton, R. A.↗

Elemental abundance determinations for meteors by spectroscopy.

Relative elemental abundance determinations for meteors by spectroscopy are discussed. Relative abundances of spectroscopically accessible elements of four major shower meteors and one sporadic meteor are presented. A sporadic meteor with dominant sodium radiation and an iron-deficient sporadic meteor are analyzed. Empirical and theoretical tests for self-absorption in optical meteor plasmas have been conducted. Both ionization and incomplete dissociation are found to severely deplete certain neutral atoms from meteor plasmas.

Harvey, G. A.↗

Electron calibration on a high-energy cosmic ray detector.

The response of the GSFC High Energy Cosmic Ray Detector has been studied using electrons in the energy range from 5.4 to 18 GeV. A semiempirical analytic form has been developed to determine the starting points and the energies of electron-induced cascade showers. The energy resolution thus obtained has a full width at half maximum of 17%, and the starting point can be determined to within 0.1 to 0.2 radiation length. The results of this response calibration provide a basis on which cosmic ray electrons can be reliably identified and analyzed in the presence of a large proton background.

Crannell, C. J.↗

Domestic wash water reclamation

System consists of filtration unit, reverse-osmosis module, tanks, pumps, plumbing, and various gauges, meters, and valves. After water is used in washing machine or shower, it is collected in holding tank. Water is pumped through series of five particulate filters. Pressure tank supplies processed water to commode water closet.

Hall, J. B., Jr.↗