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1.
The effects of changes in the space environment on the ISOPHOT photoconductivedetectors over the whole ISO mission were studied using the complete setof responsivity check measurements taken after the curing of the detectors.We found that the responsivity of the Ge-based, low bias voltage far-infrared detectors (P3, C100, and C200) is sensitive to the conditions of the Space Weather.We present evidence that an increased responsivity level (20% – 50%) after curing of the detectors is linked to the onset of geomagnetic storms. TheSi-based, high bias voltage detectors P1, P2 and PHT–SS show only small changesin their responsivity. An exception is the PHT–SL array which shows a similar,but less pronounced behaviour as the FIR detectors. While these relationshave been demonstrated by our study, a detailed physical understanding is still outstanding. The Space Weather dependent scatter of the responsivity,being the photometric scaling factor (conversion from measured photo currentto inband power on the detector), justifies the observing mode design to include frequent monitoring of its actual level. 相似文献
2.
Based on long-term spectrophotometric observations of Jupiter in the wavelength range 320–1100 nm, we investigate the variations of aerosol extinction (at 320–600 nm) and methane–ammonia absorption (at 600–1100 nm) over Jupiter's disk. We give estimates of the optical parameters for the upper cloud layer of the planet, the overlying stratospheric haze, and a Rayleigh atmosphere. 相似文献
3.
The Naval Research Laboratory flew solar X-ray ionization chamber detectors on a series of Solar Radiation (SOLRAD) satellites from 1960 through 1979. The flare responses of the SOLRAD 11 detectors are compared with those of the similar NOAA SMS/GOES detectors during two periods of common observations. The nominal GOES fluxes exceed those of SOLRAD 11 by a factor of 1.5–2 in the 0.5–4 Å band, but fall below those of SOLRAD by a factor of 2–4 in the 1–8 Å band. Significant passband differences account for these relationships between the detector responses. Since the X-ray detectors are standardized among the various SOLRAD satellites, and all detectors are closely matched among the various SMS/GOES satellites, these conversion factors allow the SOLRAD flare observations to serve as proxies for GOES X-ray observations prior to the GOES era. We summarize the detector characteristics and data sources of the 0.5–3 Å and 1–8 Å detectors for the SOLRAD series. 相似文献
4.
The HUS-Ulysses team has prepared an instrument aboard the ULYSSES spacecraft consisting of 2 CsI detectors and 2 Si surface barrier detectors for measuring X-rays in the range 5–200 keV up to 8 ms resolution. The prime objectives are the study of solar flares and of cosmic gamma-ray bursts. The ULYSSES mission will leave the ecliptic during the next solar cycle. The solar data can be used in conjunction with other experiments to measure the directivity of the emission and for correlative studies. The cosmic gamma-ray burst data will improve source localizations, allowing sensitive searches for counterparts. The energy range and the 4 field of view is well suited to the detection of the soft gamma-ray repeaters.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain 相似文献
5.
D. J. Forrest E. L. Chupp J. M. Ryan M. L. Cherry I. U. Gleske C. Reppin K. Pinkau E. Rieger G. Kanbach R. L. Kinzer G. Share W. N. Johnson J. D. Kurfess 《Solar physics》1980,65(1):15-23
The Solar Maximum Mission Gamma Ray Experiment (SMM GRE) utilizes an actively shielded, multicrystal scintillation spectrometer to measure the flux of solar gamma rays. The instrument provides a 476-channel pulse height spectrum (with energy resolution of 7% at 662 keV) every 16.38 s over the energy range 0.3–9 MeV. Higher time resolution (2 s) is available in three windows between 3.5 and 6.5 MeV to study prompt gamma ray line emission at 4.4 and 6.1 MeV. Gamma ray spectral analysis can be extended to 15 MeV on command. Photons in the energy band from 300–350 keV are recorded with a time resolution of 64 ms. A high energy configuration also gives the spectrum of photons in the energy range from 10–100 MeV and the flux of neutrons 20 MeV. Both have a time resolution of 2 s. Auxiliary X-ray detectors will provide spectra with 1-sec time resolution over the energy range of 10–140 keV. The instrument is designed to measure the intensity, energy, and Doppler shift of narrow gamma ray lines as well as the intensity of extremely broadened lines and the photon continuum. The main objective is to use this time and spectral information from both nuclear gamma ray lines and the photon continuum in a direct study of the dynamics of the solar flare/particle acceleration phenomena. 相似文献
6.
Rajmal Jain Hemant Dave A. B. Shah N. M. Vadher Vishal M. Shah G. P. Ubale K. S. B. Manian Chirag M. Solanki K. J. Shah Sumit Kumar S. L. Kayasth V. D. Patel Jayshree J. Trivedi M. R. Deshpande 《Solar physics》2005,227(1):89-122
The first space-borne solar astronomy experiment of India, namely Solar X-ray Spectrometer (SOXS), was successfully launched on 08 May 2003 on board geostationary satellite GSAT-2 of India. The SOXS is composed of two independent payloads, viz. SOXS Low-Energy Detector (SLD) Payload and SOXS High-Energy Detector (SHD) Payload. The SOXS aims to study the full-disk integrated X-ray emission in the energy range from 4 keV to 10 MeV. In this paper we present the first report on the SLD instrumentation and its in-orbit performance. The SLD payload was designed and developed at the Physical Research Laboratory in collaboration with various centers of Indian Space Research Organisation (ISRO). The basic scientific aim of the SLD payload is to study solar flares in the energy range from 4 to 60 keV with high spectral and temporal resolution. To meet these requirements, the SLD payload employs state-of-the-art solid state detectors, the first time for a solar astronomy experiment, viz. Si PIN (4 –25 keV), and cadmium–zinc–telluride (4 –60 keV). With their superb high-energy resolution characteristics, SLD can observe iron and iron–nickel complex lines that are visible only during solar flares. In view of its 3.4 FOV, the detector package is mounted on a Sun Aspect System, for the first time, to get uninterrupted observations in a geostationary orbit. The SLD payload configuration, its in-flight operation, and the response of the detectors are presented. We also present the first observations of solar flares made by the SLD payload and briefly describe their temporal and spectral mode results. 相似文献
7.
During the last half of 1977 the UCSD/MIT Hard X-Ray and Low Energy Gamma-Ray Experiment of HEAO-1 observed two of the three gamma-ray bursts detected by at least three satellites. The first of these bursts (20 October, 1977) had a fluence of (3.1±0.5)×10–5 erg cm–2 integrated over the energy range 0.135–2.05 MeV and over its duration of 38.7 s, placing it among the largest bursts observed. The second (10 November, 1977) had a fluence of (2.1±0.8)×10–5 erg cm–2 integrated over the energy range 0.125–3 MeV and over its duration of 2.8 s. The light curves of both bursts exhibit time fluctuations down to the limiting time resolution of the detectors (0.1 s). The spectrum of the 20 October, 1977 burst can be fitted with a power law (index –1.93±0.16), which is harder than other reported gamma-ray burst spectral fits. This burst was detected up to 2.05 MeV, and approximately half of its energy was emitted at photon energies above 0.5 MeV. The spectrum of the 10 November, 1977 burst is softer (index –2.4±0.7) and is similar to the spectrum of the 27 April, 1972 burst.Paper presented at the Symposium on Cosmic Gamma-Ray Bursts held at Toulouse, France, 26–29 November, 1979. 相似文献
8.
Matthias Tecza Niranjan Thatte Fraser Clarke Timothy Goodsall Myrto Symeonidis 《New Astronomy Reviews》2006,49(10-12):647
SWIFT is an adaptive optics assisted integral field spectrograph covering the I and z astronomical bands (0.7–1.0 μm) at a spectral resolving power R 5000. At its heart is an all-glass image slicer with high throughput based on a novel de-magnifying design allowing a compact instrument. SWIFT profits from two recent developments: (i) the improved ability of second generation adaptive optics systems to correct for atmospheric turbulence in SWIFTS’s bandpass, and (ii) the availability of CCD array detectors with high quantum efficiency at very red wavelengths. It is a dedicated integral field spectrograph, specifically built to address a range of interesting astrophysical questions. 相似文献
9.
The modification of crystalline olivine under irradiation with 1.43-MeV deuterons was studied experimentally. For the first time, the partial destruction of olivine in the surface (100–200 nm) layer was found at a current density of 5–10 A/cm2. This effect is caused by ionization and desorption of Mg and Fe atoms at deuteron fluences (3–8 × 1016cm–2) which are substantially below the amorphization threshold. It was suggested that the negative charge of the anion group SiO4
4–is neutralized by the interaction with the deuterium ions and Frenkel pairs. The mechanism of sputtering of the crystalline olivine surfaces under irradiation with H, D, He, and Ar ions was studied using of the TRIM 98 program. 相似文献
10.
All four large EUV bursts (peak 10–1030 Å flux enhancements 2 ergs cm–2 s–1 at 1 AU as deduced from sudden frequency deviations), for which there were available concurrent white light observations of at least fair quality, were detected as white light flares. The rise times and maxima of the white light emissions coincided with rise times and maxima of the EUV bursts. The frequency of strong EUV bursts suggests that white light flares may occur at the rate of five or six per year near sunspot maximum. All of the white light flare areas coincided with intense bright areas of the H flares. These small areas appeared to be sources of high velocity ejecta in H. The white light flares occurred as several knots or patches of 2 to 15 arc-sec diameter, with bright cores perhaps less than 2 arc-sec diameter (1500 km). They preferred the outer penumbral borders of strong sunspots within 10 arc-sec of a longitudinal neutral line in the magnetic field. The peak continuum flux enhancement over the 3500–6500 Å wavelength range is about the same order of magnitude as the peak 10–1030 Å flux enhancement. 相似文献
11.
Jafar Arkani-Hamed 《Earth, Moon, and Planets》1991,55(1):51-68
Assuming that the surface topography of the Ovda and Thetis plateaus, and that of the saddle region between Thetis and Atla plateaus, is due to surface subsidence of oceanic-type thermal boundary layers, we calculated the temperature at 200 km beneath the plateaus to be about 1600 C, and that beneath the saddle region to be about 1400–1500 C. The total subsidence of Ovda plateau in the last 3/4 of its existence, i.e. between 200 km and 800 km off the postulated ridge axis, suggests that the plateau is probably a young feature, less than 40 m.y. old. The spreading plate models imply a half-spreading rate of 2.3–5.3 cm/yr for the plateaus and 2–2.8 cm/yr for the saddle region. 相似文献
12.
C. Lucas Ph. Pantigny D. Alloin C. Césarsky P. O. Lagage H. U. Käufl J. L. Monin 《Experimental Astronomy》1994,3(1-4):273-276
Since 1984, the CEA-LETI-LIR (Infrared Laboratory) has been involved in development of Si:Ga/DRO hybrid detector arrays dedicated to imaging of astronomical sources in the 8–13 m range. Successively, 32×32 element arrays were successfully manufactured for the ISOCAM camera and 64×64 arrays were fabricated for ground-based imaging. The latter detectors have been integrated in 3 cameras (C10, CAMIRAS and TIMMI for ESO) and have led to excellent astrophysical results since 1990.To equip instruments to be mounted on very large telescopes such as the European VLT at ESO, manufacture of new arrays has been undertaken and is currently under way at CEA-LETI-LIR. These new arrays will have a 128×192 format and will present the outstanding essential feature that their storage capacity will be able to be changed according to observation conditions (2 capacities will be implemented in the pixel).The main characteristics of these new detectors will be presented in this paper. 相似文献
13.
The energy spectra of protons at energies in the range of about 1–100 MeV are investigated during time periods of low solar activity using data sets from near Earth spacecraft. These populations pose a tough experimental and theoretical problem that remains unsolved up to now. We attempt to provide a consistent definition of low-flux quiet-time periods relevant to low solar activity as well as quasi-stationary periods useful at higher levels of solar activity. Using statistical methods, the possible instrumental contribution to the lowest observed proton fluxes for various detectors is estimated. We suggest and prove that there exists a low-flux population of charged particles in the energy range of about 1–10 MeV, which is present in the inner heliosphere even during the quietest conditions at lowest solar activity. The dynamics of the variations of proton spectra over the solar cycle is investigated. A series of low-flux periods is examined in detail and energy spectra of protons are approximated in the form of J(E)=AE
–+CE. By determining the best fitting parameters to the energy spectra correlations are made among them as well as with monthly sunspot numbers characterizing solar activity. It has been demonstrated that the value of the energy minimum of proton spectrum E
min that `divides' the two populations – `solar/heliospheric' and `galactic' – is shifted towards higher values with increasing solar activity. Protons have been argued to be predominantly of solar origin up to several MeV near the solar cycle minimum and up to 20–30 MeV at maximum. The slope of the lower spectrum branch (parameter ) slightly decreases with increasing solar activity. The minimum fluxes observed during the last 3 minima of solar activity are compared; the lowest fluxes were those during the 1985–1987 period. 相似文献
14.
Fisenko A. V. Verchovsky A. B. Semjonova L. F. Pillinger C. T. 《Solar System Research》2004,38(5):383-393
We measured the contents and isotopic compositions for C, N, and noble gases in the diamond fractions separated in a heavy liquid ( = 2.9 g/cm3) from a sample enriched with diamond from the Novo Urei ureilite. The results show that the concentrations of nitrogen and noble gases in the diamond fraction isolated from the supernatant (the fraction is named DNU-1) are more than a factor of 1.5 higher than those in the diamond fraction from the residue (DNU-2). This difference is probably caused by smaller sizes of grains and (or) clusters of smaller grains as well as by larger defectiveness of the crystal lattice of the diamond in the DNU-1 fraction as compared to DNU-2. Both fractions are similar in the isotopic composition of C and N and in the ratios of trapped chemical elements. The results obtained and the published data concerning C, N, and noble gases in different fractions of other ureilites allow us to conclude the following. (1) The ureilite diamond was most likely formed from graphite and the fine-grained crystalline (or semiamorphous) carbonaceous phase as a result of shock transformation in the parent bodies. (2) The negative result in the search for the isotopically light component of nitrogen (15N is about –100) in the Antarctic unshocked ureilite ALH 78019 (Rai et al., 2002), which introduced serious difficulties for explaining the origin of the ureilite diamond in the parent bodies during the impact, is most likely caused by the absorption of atmospheric nitrogen by the carbonaceous material in the processes of terrestrial weathering. (3) The source of light nitrogen (15N –100) in the ureilite diamond was probably the presolar diamond in the initial carbonaceous material of the ureilite parent bodies, because the impurity elements, including nitrogen (15N < –350), in this diamond could be trapped in the magmatic processes by the carbonaceous material, which became a precursor of the ureilite diamond in the shock event. 相似文献
15.
M. P. Nakada 《Solar physics》1979,62(2):343-346
An attempt is made to specify coronal hole boundaries in the brightness of 284 of Fe xv. This is done by evaluating brightnesses of 284 at boundaries selected by various groups. These results are in quite good agreement and suggest a brightness value of (0.8±0.4)×1012 photons cm–2 s–1 sr–1 for coronal hole boundaries in 284. The examination of a number of isophote maps near this boundary brightness shows no consistent brightness gradient. 相似文献
16.
An experiment made with a baloon-borne large volume (16×16×24 cm3) omnidirectional plastic scintillator sensitive to high-energy -radiation is described. Two flights were carried out on 25 November, 1973 and 24 February, 1978 at high geomagnetic cut-off rigidities. For an omnidirectional detector and for energies greater than several MeV, most of the detected photons are secondary -rays produced through interactions of the charged cosmic rays with the atmosphere. To unfold the observed pulse height spectrum and obtain the incident -ray spectrum, the detector response function is calculated numerically. By using this response function a differential flux dJ/dE=(0.33±0.1)E
–1.2±0.2 photons cm–2 s–1 MeV–1 averaged over all zenith angles, is estimated for the atmospheric -radiation, at 5 g cm–2, in the 10–100 MeV energy range. This result is compared with other observations made with different types of detectors and at different geomagnetic latitudes.Members of the Carrera del Investigador Cientifico y Tecnológico del Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) from Argentina. 相似文献
17.
Michael Moutsoulas 《Astrophysics and Space Science》1985,110(1):197-201
The heliometer has been the only instrument for the measurement of the lunar physical libration for more than a century. Bessel (1839), who introduced the use of the heliometer for the systematic measurement of the relative positions of craters on the lunar disc, has also developed the necessary formulation for the calculation of the lunar physical libration from the heliometric measurements. That methodology is presented, and results obtained by Bessel's students and other investigators who followed Bessel's method, are discussed.Communication presented at the International Conference on Astrometric Binaries, held on 13–15 June, 1984, at the Remeis-Sternwarte Bamberg, Germany, to commemorate the 200th anniversary of the birth of Friedrich Wilhelm Bessel (1784–1846). 相似文献
18.
G. Chambon K. Hurley M. Niel R. Talon G. Vedrenne I. V. Estuline O. B. Likine 《Solar physics》1981,69(1):147-159
The November 22, 1977 solar flare was observed at energies up to 4.9 MeV by French-built gamma ray detectors aboard the Soviet Prognoz-6 satellite. The data show evidence for 2.23 and 4.43 MeV line emission, with the 2.23 MeV emission occurring about 3 min after the flare onset in hard X-rays. The line intensities, 0.11 cm–2s–1 and 0.06 cm–2s–1 for the 2.23 and 4.43 lines, respectively, are roughly comparable to intensities observed in other events. Particle detectors aboard the Prognoz-6 satellite, however, recorded a proton flux much lower than that observed for the 4 August 1972 event. It is shown that this may be taken as evidence for a thick target interpretation of the proton interactions in the solar atmosphere. 相似文献
19.
A cryogenic astronomical spectrometer for the NASA Infrared Telescope Facility is described. This spectrometer will employ an array of at least 20 detectors and provide a resolving power of 100 to 1500 at 1–5 m. The resolving power will be adjustable by changing gratings.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. 相似文献
20.
Photometry and spectrophotometry of the proper motion star G 82-23 are presented. A comparison with subdwarfs and white dwarfs in the same range of temperature shows only partial agreement. If the parallax is taken into account, the best explanation of this object seems to be a binary structure with a K-subdwarf and a DC-white dwarf.Communication presented at the International Conference on Astrometric Binaries, held on 13–15 June, 1984, at the Remeis-Sternwarte Bamberg, Germany, to commemorate the 200th anniversary of the birth of Friedrich Wilhelm Bessel (1784–1846). 相似文献