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 Solar Modulation Effects in Terrestrial Production of Carbon-14

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 133-158 ◽  
Author(s):  
Giuliana Castagnoli ◽  
Devendra Lal
Keyword(s):  
Solar Activity ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Carbon 14 ◽  
Cosmic Ray Modulation ◽  
The Earth ◽  
Secular Variations ◽  
Galactic Cosmic Ray ◽  
Long Term Variations

This paper is concerned with the expected deviations in the production rate of natural 14C on the earth due to changes in solar activity. We review the published estimates of the global production rates of 14C due to galactic and solar cosmic ray particles, and present new estimates of the expected secular variations in 14C production, taking into account the latest information available on galactic cosmic ray modulation and long-term variations in solar activity.

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.

The long-term variation of the cosmic radiation

1968 ◽  
Vol 46 (10) ◽  
pp. S903-S906 ◽  
Author(s):  
J. A. Lockwood ◽  
W. R. Webber
Keyword(s):  
Neutron Monitor ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
Direct Measurements ◽  
Term Variation ◽  
Primary Cosmic Radiation

The variation in the cosmic-ray intensity recorded by neutron monitors from 1958 to 1965 has been investigated to deduce the form of the solar modulation of the cosmic radiation. The observed changes in the intensity at the neutron monitor stations, averaged over quarter-year periods, were compared with changes calculated using modulation functions depending upon energy, rigidity, and velocity × rigidity. These calculations were based upon the revised differential response functions deduced by Lockwood and Webber (1967). The variance between the observed and calculated changes in the neutron monitor intensities at different stations was minimized to determine the best form of the solar modulation function. We find that the change of the primary cosmic radiation, deduced from the change in the neutron monitor intensity as well as from direct measurements of the primary flux, can be described by a modulation of the form exp(–K/P) in the rigidity range 0.5 < P < 50 GV. The change between 1959 and 1965 can be fitted with K = 1.94 ± 0.09 and between 1963 and 1965 with K = 0.36 ± 0.05.

scholarly journals The primary cosmic-ray electron spectrum in the energy range from 300 MeV to 4 BeV from 1964 to 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S892-S895 ◽  
Author(s):  
Jacques L'heureux ◽  
Peter Meyer
Keyword(s):  
Energy Spectrum ◽  
Electron Spectrum ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Primary Electron ◽  
Counter Telescope ◽  
Improved Accuracy ◽  
Primary Electrons

Measurements of the primary electron spectrum were made during the summers of 1964, 1965, and 1966 using a balloon-borne counter telescope flown from Fort Churchill, Manitoba. Several balloon flights were carried out in each year in order to eliminate short-term intensity variations. This paper addresses itself to two questions: (1) the determination of the energy spectrum of primary electrons in the energy interval from 300 MeV to 4 BeV; and (2) the long-term intensity variations of the primary electron flux from 1964 through 1966. The energy spectrum was determined with improved accuracy in 1966 and agrees with our previous results. Comparison of the electron spectra obtained in 1964, 1965, and 1966 shows that, within the errors of our measurements, no long-term intensity variation existed. The upper limit for the change of flux with respect to 1965 amounts to 20% in all energy intervals studied.[Formula: see text]

Solar modulation of galactic cosmic rays near solar minimum (1965)

1968 ◽  
Vol 46 (10) ◽  
pp. S887-S891 ◽  
Author(s):  
V. K. Balasubrahmanyan ◽  
D. E. Hagge ◽  
F. B. McDonald
Keyword(s):  
Cosmic Rays ◽  
Solar Minimum ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Solar Modulation ◽  
Time Behavior ◽  
Cosmic Ray Intensity ◽  
Radial Gradient

The results of the continuous monitoring of the intensity of cosmic rays (of energy > 50 MeV) with identical G-M counter telescopes flown in satellites IMP I, II, and III and OGO-I are presented along with the differential spectrum studies obtained from balloon flights at Fort Churchill and from satellites. A comparison of the time behavior of the G-M counter data with Deep River neutron monitor data suggests the presence of a "hysteresis" type of behavior due to spectral changes occurring near solar minimum. The existence of this "hysteresis" suggests that the radial gradient of cosmic rays near the earth could be much smaller than the ~ 10%/AU obtained by O'Gallagher and Simpson (1967) and O'Gallagher (1967) at higher energies. The long-term intensity variation of cosmic rays seems to follow the Ap index rather closely in phase, in contrast to sunspot numbers which display a pronounced phase difference with cosmic-ray intensity. The differential spectra of protons and He nuclei have been analyzed in terms of two different models for the propagation in the interplanetary medium. The modulations indicated by the present data seem to disagree with a diffusion coefficient proportional to βR where β and R are the velocity and rigidity of the particle respectively (Jokipii 1966).

Some Astrophysical Implications of Recent Measurements on the Intensity of Cosmic-Ray Electrons

1968 ◽  
Vol 1 (3) ◽  
pp. 112-113 ◽  
Author(s):  
W.R. Webber
Keyword(s):  
Electron Spectrum ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
List Type ◽  
Secondary Electrons ◽  
The Earth ◽  
Thermal Radio Emission ◽  
The Galaxy ◽  
Electron Intensity ◽  
Spiral Arm

We have extended our recent measurements on the extraterrestrial cosmic ray electron spectrum, this spectrum now being determined over the energy range from ~15 MeV to 6 GeV. The extraterrestrial electron intensity between 15 MeV and 200 MeV can be determined unambiguously by studying the diurnal variation of these particles. We have also measured the effects of the 11-year solar modulation on the electrons, thus enabling the electron spectrum observed near the Earth to be extrapolated to the local region of the spiral arm. It is the purpose of this paper to relate these measurements to: (i) calculations of ‘secondary’ electrons produced by cosmic ray nuclei moving in the Galaxy; and(ii) the observations of non-thermal radio emission from disk components of the Galaxy.

Interplanetary and solar electrons of energy 3–12 MeV

1968 ◽  
Vol 46 (10) ◽  
pp. S761-S765 ◽  
Author(s):  
T. L. Cline ◽  
F. B. McDonald
Keyword(s):  
Interplanetary Space ◽  
Solar Physics ◽  
Strong Dependence ◽  
Cosmic Ray ◽  
High Energy ◽  
Solar Modulation ◽  
Relativistic Electrons ◽  
Time Histories ◽  
Electron Intensity ◽  
Time Variations

This paper reviews two topics related to the low-energy relativistic electrons detected in interplanetary space with the satellites IMP-I, IMP-II, and IMP-III:1. The first observations of 3–12-MeV solar-flare electrons in interplanetary space are presented. The solar electrons detected have kinetic energies nearly two orders of magnitude higher than any previously studied; thus, although flare events with a detectable flux of such particles occur relatively rarely, their study provides a new parameter in solar physics. The 7 July and 14 September 1966 events are outlined in detail, having the greatest relativistic electron to medium-energy proton ratios of the events detected before 1967. These events contrast with the 28 August 1966 event, which was intense in nucleons but contained no detectable component of relativistic electrons. The electron time histories are shown to have delayed onsets, and to be similar in form to those of high-energy protons, and the energy spectra and other features are described.2. Progress in the study of the solar modulation of interplanetary 3–12-MeV electrons is reviewed. Characteristics of the electron-intensity time variations during parts of 1963–67 are outlined; they are shown to be consistent with the hypothesis of the primary cosmic-ray nature of these particles and with a strong dependence on the local field conditions.

Local thickness determination by Electron Energy Loss Spectroscopy

1994 ◽  
Vol 52 ◽  
pp. 944-945
Author(s):  
Suichu Luo ◽  
John R. Dunlap ◽  
Richard W. Williams ◽  
David C. Joy
Keyword(s):  
Energy Loss ◽  
Analytical Electron Microscopy ◽  
Mean Free Path ◽  
Single Scattering ◽  
Specimen Thickness ◽  
Three Dimension ◽  
Angular Correction ◽  
Electron Intensity ◽  
Image Position ◽  
Inelastic Mean Free Path

In analytical electron microscopy, it is often important to know the local thickness of a sample. The conventional method used for measuring specimen thickness by EELS is:where t is the specimen thickness, λi is the total inelastic mean free path, IT is the total intensity in an EEL spectrum, and I0 is the zero loss peak intensity. This is rigorouslycorrect only if the electrons are collected over all scattering angles and all energy losses. However, in most experiments only a fraction of the scattered electrons are collected due to a limited collection semi-angle. To overcome this problem we present a method based on three-dimension Poisson statistics, which takes into account both the inelastic and elastic mixed angular correction.The three-dimension Poisson formula is given by:where I is the unscattered electron intensity; t is the sample thickness; λi and λe are the inelastic and elastic scattering mean free paths; Si (θ) and Se(θ) are normalized single inelastic and elastic angular scattering distributions respectively ; F(E) is the single scattering normalized energy loss distribution; D(E,θ) is the plural scattering distribution,

Severe conduit stenosis in a patient with Fontan circulation with a Y-shaped Dacron conduit

2021 ◽  
pp. 1-3
Author(s):  
Daiji Takajo ◽  
Preetha L. Balakrishnan ◽  
Sanjeev Aggarwal
Keyword(s):  
Energy Loss ◽  
Polyethylene Terephthalate ◽  
Rare Complication ◽  
Flow Distribution ◽  
Fontan Circulation ◽  
Distribution Data ◽  
Extracardiac Fontan ◽  
Fontan Palliation

Abstract Conduit stenosis is a major, albeit rare, complication following the Fontan palliation. A single-baffle conduit with polytetrafluoroethylene is widely used for an extracardiac type Fontan palliation. A polyethylene terephthalate conduit (Dacron) is sometimes used for the conduit when more flexibility is required. A Y-shaped conduit is rarely used, but it may reduce the energy loss and achieve better hepatic flow distribution. Data on the long-term patency and complications when using a Y-shaped Dacron conduit is lacking. We report a case of a severely stenotic Y-shaped Dacron conduit in a patient who underwent extracardiac Fontan palliation.

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