Cosmic-ray proton and helium spectra and solar modulation effects in the new solar cycle measured with a four-element counter telescope

1968 ◽  
Vol 46 (10) ◽  
pp. S883-S886 ◽  
Author(s):  
J. F. Ormes ◽  
W. R. Webber
Keyword(s):  
Scintillation Counter ◽  
Pulse Height ◽  
Cosmic Ray ◽  
Geometrical Factor ◽  
Solar Modulation ◽  
Primary Proton ◽  
Before And After ◽  
Order Of Magnitude ◽  
Helium Spectra ◽  
Counter Telescope

In the summers of 1965 and 1966 we have continued our studies begun in 1963 on the primary proton and helium spectra and the effects of solar modulation. Data are available from four additional balloon flights at Fort Churchill using the earlier version of the Cerenkov-scintillation counter telescope (Ormes and Webber 1966), and a new four-element double-scintillation (dE/dx), Cerenkov-scintillation + range telescope. This latest telescope employs pulse-height analysis on both dE/dx counters and the Cerenkov-scintillation counter. Various consistency requirements may be set between pulse heights. These serve to reduce background effects by an order of magnitude over the previous system. The geometrical factor of the telescope is 55.4 sr cm2. The results reported here will cover the proton and helium spectra from 100 MeV/nucleon to 2 BeV/nucleon and their time variation. They will show that the fractional changes in the differential proton spectra can be represented by (rigidity)−1 both before and after the sunspot minimum and that there is no evidence for any hysteresis effects between protons of 100 MeV to 2 BeV and energies to which neutron monitors respond.

RESPONSE OF MU-MESON DETECTORS DEEP IN THE ATMOSPHERE TO PRIMARY COSMIC-RAY PARTICLES OF MAGNETIC RIGIDITY BETWEEN 10 AND 25 GV

1967 ◽  
Vol 45 (5) ◽  
pp. 1643-1653 ◽  
Author(s):  
T. Mathews ◽  
G. G. Sivjee
Keyword(s):  
Sea Level ◽  
Scintillation Counter ◽  
Cosmic Ray ◽  
Decay Rates ◽  
Atmospheric Effects ◽  
Ionization Chambers ◽  
Corrected Data ◽  
Counter Telescope ◽  
East West ◽  
Different Altitudes

The cosmic-ray mu-meson intensities at three different altitudes at the equator were measured as a function of zenith and azimuth angles by means of a portable scintillation counter telescope of semi-opening angles 23°. The data were analyzed to assess the effects of differences in pi- and mu-meson decay rates on the intensity of the penetrating ionizing component at different zenith angles. It was found that the changes of intensity as a function of zenith angles could be attributed almost entirely to differences in atmospheric absorption, provided that at all zenith angles the threshold rigidities were the same. Hence the intensities measured at different zenith angles in the east–west plane at the equator could be corrected to remove the atmospheric effects and the corrected data used for determining the response of meson detectors at sea level to particles of rigidity up to 25 GV. The response curve thus obtained is presented and compared with that obtained from sea-level latitude surveys by means of ionization chambers.

A LARGE-AREA LIQUID SCINTILLATION COUNTER AND SOME MEASUREMENTS ON HIGH-ENERGY COSMIC-RAY PARTICLES

1958 ◽  
Vol 36 (1) ◽  
pp. 54-72 ◽  
Author(s):  
C. H. Millar ◽  
E. P. Hincks ◽  
G. C. Hanna
Keyword(s):  
Energy Loss ◽  
Liquid Scintillation ◽  
Scintillation Counter ◽  
Pulse Height ◽  
Central Area ◽  
Cosmic Ray ◽  
High Energy ◽  
Liquid Scintillation Counter ◽  
Height Distribution ◽  
Half Maximum

A liquid scintillation counter is described which consists of a [Formula: see text] in. by [Formula: see text] in. by 2 in. Plexiglas tank of terphenyl plus α-naphthylphenyloxazole (αNPO) in triethylbenzene. The tank is surrounded by MgO powder and viewed by a total of eight RCA Type 5819 photomultiplier tubes along two opposite edges. For normally incident fast μ-mesons a peaked pulse height distribution is observed, 20.5% in width at half-maximum for the central area of the counter, broadening to 25–30% at the perimeter, and estimated to be 25% over-all. When the Landau distribution in energy loss (width 18% at half-maximum) and the geometric spread are taken into account, a counter resolution function 8% in width at half-maximum is obtained for the central area of the counter, or 18% for the counter as a whole.The most probable pulse height for 0.30 Bev. μ-mesons is 1.6 ± 0.5% higher than for 2.2 Bev. μ-mesons, in close agreement with the Bethe–Bloch theory as extended by Symon and with a density correction calculated by the method of Sternheimer. Pulse heights from protons in the region 0.3 to 0.8 Bev. vary directly with the theoretically computed energy loss in the counter. Peak position and resolution are unchanged by a flux of 12 mr./hr. of thorium γ-rays.

A cosmic-ray counter telescope for high mass resolution

1968 ◽  
Vol 46 (10) ◽  
pp. S1122-S1124
Author(s):  
G. D. Badhwar ◽  
C. L. Deney ◽  
B. R. Dennis ◽  
M. F. Kaplon
Keyword(s):  
Light Output ◽  
Nonlinear Behavior ◽  
Cosmic Ray ◽  
Mass Resolution ◽  
High Mass ◽  
Geometrical Factor ◽  
Crystal Thickness ◽  
High Mass Resolution ◽  
Plastic Scintillators ◽  
Counter Telescope

A dE/dx by E counter telescope consisting of two ¼-in.-thick plastic scintillators as the dE/dx elements and a 5-in.-deep NaI(Tl) crystal as the E element is described. The geometrical factor of the system is 6 cm2 sr and is energy independent for stopping particles. The calibration of the detector and its response to sea-level muons and the low-energy nuclei of cosmic radiation are presented. The expected mass resolution is compared to that observed, and they are found to be in excellent agreement. Protons, deuterons, 3He, 4He, and heavier nuclei are all resolved over the energy range corresponding to the crystal thickness. Information on the nonlinear behavior of the light output from the plastic scintillator NE102 as a function of ionization loss is presented.

IONIZING POWER OF COSMIC RAY PARTICLES AT SEA LEVEL

1951 ◽  
Vol 29 (6) ◽  
pp. 495-504 ◽  
Author(s):  
S. D. Chatterjee
Keyword(s):  
Sea Level ◽  
Distribution Curve ◽  
Pulse Height ◽  
Cosmic Ray ◽  
Relativistic Electrons ◽  
Height Distribution ◽  
Soft Component ◽  
Pulse Height Distribution ◽  
Counter Telescope ◽  
Number Of Particles

Using a proportional counter telescope arrangement, experiments have been carried out at sea level to explore the nature and ionizing power of particles in the soft component of cosmic radiation and those produced under 1.8 cm. and 20 cm. of lead. The results indicate a preponderance of relativistic electrons in the soft component and under 20 cm. of lead. Under 1.8 cm. of lead there is some disagreement with the calculated pulse height distribution curve but this can be attributed to the production of showers in the lead. These showers would obscure the presence of a small number of particles of unusually high ionizing power, if such exist.

Long-term variations of the primary cosmic-ray electron component

1968 ◽  
Vol 46 (10) ◽  
pp. S896-S899 ◽  
Author(s):  
Jacques L'Heureux ◽  
Peter Meyer ◽  
Satya Dev Verma ◽  
Rochus Vogt
Keyword(s):  
Energy Loss ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Electron Component ◽  
Fractional Change ◽  
Overlapping Data ◽  
Electron Intensity ◽  
Experimental Errors ◽  
Counter Telescope

The intensity of primary cosmic-ray electrons has been measured from 1960 through 1966 at balloon altitude over Ft. Churchill, Manitoba. Initial measurements were made with an energy-loss vs. range counter telescope from 1960 through 1964. From 1964 through 1966 an energy-loss vs. total energy counter telescope was used. Overlapping data exist for both instruments in 1964. Our results are consistent with the absence of a solar modulation effect for electrons in the 0.25 to 1.05 BV rigidity range. The experimental errors lead to an upper limit of 60% for the possible fractional change of the electron intensity over this period.

scholarly journals A Numerical Study of the Solar Modulation of Galactic Protons and Helium from 2006 to 2017

2021 ◽  
Vol 257 (2) ◽  
pp. 48
Author(s):  
Xiaojian Song ◽  
Xi Luo ◽  
Marius S. Potgieter ◽  
XinMing Liu ◽  
Zekun Geng
Keyword(s):  
Time Dependence ◽  
Diffusion Coefficients ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Transport Processes ◽  
Solar Modulation ◽  
Relevant Parameter ◽  
Observational Uncertainty ◽  
Helium Spectra ◽  
Rigidity Dependence

Abstract With continuous measurements from space-borne cosmic-ray detectors such as AMS-02 and PAMELA, precise spectra of galactic cosmic rays over the 11 yr solar cycle have become available. For this study, we utilize proton and helium spectra below 10 GV from these missions from 2006 to 2017 to construct a cosmic-ray transport model for a quantitative study of the processes of solar modulation. This numerical model is based on Parker’s transport equation, which includes four major transport processes. The Markov Chain Monte Carlo method is utilized to search the relevant parameter space related to the drift and the diffusion coefficients by reproducing and fitting the mentioned observed spectra. The resulting best-fit normalized χ 2 is mainly less than 1. It is found that (1) when reproducing these observations the parameters required for the drift and diffusion coefficients exhibit a clear time dependence, with the magnitude of the diffusion coefficients anticorrelated with solar activity; (2) the rigidity dependence of the resulting mean free paths varies with time, and their rigidity dependence at lower rigidity can even have a larger slope than at higher rigidity; (3) using a single set of modulation parameters for each pair of observed proton and helium spectra, most spectra are reproduced within observational uncertainty; and (4) the simulated proton-to-helium flux ratio agrees with the observed values in terms of its long-term time dependence, although some discrepancy exists, and the difference is mostly coming from the underestimation of proton flux.

A long-distance coincidence radio-pulse experiment

1968 ◽  
Vol 46 (10) ◽  
pp. S250-S254 ◽  
Author(s):  
D. J. Fegan ◽  
B. McBreen ◽  
E. P. O'Mongain ◽  
N. A. Porter ◽  
P. J. Slevin
Keyword(s):  
Radio Pulse ◽  
Scintillation Counter ◽  
Pulse Height ◽  
Cosmic Ray ◽  
Pulse Height Spectrum ◽  
Long Distance ◽  
Pulse Experiment ◽  
Single Station ◽  
Random Expectation ◽  
Set Up

Three radio receiving stations, operating at 45, 70, and 70 MHz center frequencies, have been set up for air shower detection. Separations are 10, 12, and 20 km between stations. Pulses are selected by combinations of antennae pointing towards magnetic west at large zenith angles. In 1 000 hours of operation, about 150 events have been observed in excess of the random expectation over the 10-km distance. Over the 12-km separation, no excess has been observed in 244 hours, but operation is restricted in this case by intervening hills to zenith angles less than 84°. Over the 20-km separation, a small excess is observed, which may be due to chance. In a series of subsidiary experiments, radio pulses have been correlated with night-sky Cerenkov detectors and a scintillation counter, and with receivers at 12, 35, and 500 Mc/s. From these experiments the rate of detection of cosmic-ray showers at a single station is believed to be at least 1 per hour, or about 5–10% of the radio pulses selected. Local radio coincidences at individual stations are in excess of random expectation, and the pulse-height spectrum for local events is steeper than would be expected for cosmic-ray events or interference pulses. The long-distance coincidences have not been established directly as cosmic-ray events, but are consistent with this interpretation.

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