X-ray Photometer Research Articles

Influence of the energy calibration of broad-band X-ray detectors on determination of the plasma parameters

Standard broad-band measurements of the solar soft X-ray spectra are used to derive averaged values of parameters characterizing flaring plasmas i.e. the temperature and emission measure. Derived values of these parameters may be used as a basis for estimating the thermal energy content, densities and other thermodynamic properties of flares. These derived numerical values are subject to errors inherent in the uncertainties of the energy calibration, filter transmission etc., of the measuring device. In this paper we investigate the influence of the uncertainties of the detector's energy calibration on the accuracy of the derived physical characteristics of solar flares. This analysis is based on data obtained from the X-ray photometer flown aboard the Prognoz-10 (Intershock) satellit

Observations of 1–8 Å solar X-ray variability during solar cycle 21

One of the goals of the Solar Electromagnetic Radiation Flux Study (SERFS) for the World Ionospheric-Thermospheric Study (WITS) is to provide a more complete record of the variation of the daily 1–8 Å solar soft X-ray flux. As part of this study, I will calculate the daily mean and the daily background X-ray fluxes. The background fluxes, which I present in this paper, should be indicators of the quiescent X-ray flux principally from active regions. In contrast to this daily background flux, the daily mean flux includes the variable emissions from flares and coronal mass ejections. Although the present study uses 15 years of data from the NOAA Geostationary Operational Satellites (GOES) for 1974 to 1988, the inclusion of Solar Radiation (SOLRAD) data could extend this type of analysis back to 1964. In this paper, daily background X-ray fluxes in the form of monthly averages and annually-smoothed (13-month) values are presented for Solar Cycle 21. Intermediate term variations (on the scale of months) of the 1–8 Å background flux roughly mimic those of other chromospheric and coronal indices such as Ca K, Helium 10830 Å, and 10-cm radio flux. The annually-smoothed daily background X-ray flux was unique in peaking the latest and in showing no broad maximum. This annually-smoothed behavior is best matched by photospheric white-light facular areas. I also discuss anticipated future developments in soft X-ray monitoring. These include a new series of full-Sun soft X-ray photometers on the non-spinning GOES I-M. Also on GOES will be the operational USAF-NOAA Solar X-ray Imagers measuring the 8–20 Å, the 20–60 Å, and the thermospherically-crucial 255–300 Å bands. Nevertheless, this report and that of /1/ both note the continuing existence of an “XUV flux measurement gap,” with no long-term monitoring being planned between the soft X-ray region and the Lyman-alpha wavelengths.

Organisation of a unified system of energetic calibration of X-ray experiments

X-ray data obtained by the Prognoz 5,6,7 and 8 hard X-ray photometers are compared with the measurements carried out by similar instruments aboard the Solrad 11, ISEE 3, SMM and Hinotori satellites. Using the method of relative amplitude analysis, the apparent disagreement in the energy discrimination level calibration between the instruments is pointed out. The results of the comparison and the possible sources of disagreement are given. We suggest an international effort be made to develop a system of uniform pre-launch calibration of photometers based on a reference calibration source.

Identification and characteristics of source flares emitting 3-He or Fe enriched cosmic rays in the period September to December 1977

During the observation of solar cosmic rays on the Prognoz 6 and Helios 1 and 2 spacecrafts, several events with anomalous composition of accelerated particles (higher abundance of 3-He or Fe nuclei) occurred. We found seven such events from the period September to December 1977 for which data from the Prognoz 6 solar X-ray photometer are available. This material together with published optical and radio data from terrestrial observatories enabled us to identify more reliably the source flares and describe their characteristics. It turned out that the character of X-ray emission accompanying the emission of accelerated particles with anomalous composition shows no pronounced difference from other flares. No correlation has been found among the ratio 3-He/4-He and the angular distance between the field lines connected with the source flare and the place of observation. If a solar flare with anomalous ratio 3-He/4-He appears in a given active region, this region will probably produce other anomalous events.

Magnetically Conjugate Observations of the Radio Aurora

OBSERVATIONS of magnetically conjugate phenomena at auroral latitudes have been made with measuring instruments conjugately located in the north and south hemispheres and including magnetometers, riometers, balloon-borne X-ray detectors, photometers and all-sky cameras, both fixed and airborne1,2. These measurements have shown that there can be close correspondence between magnetic variations, precipitating particle fluxes and optical emissions at conjugate locations.

The Use of Silicium Solid-State Detector in Solar X-Ray Measurements

The silicium solid-state detector has been used as control-detector in the X-ray photometer system on board of the satellite Interkosmos 1.The effectiveness of the use of such detector as control-unit for radiation-belts has been confirmed also as independent indicator of high energy X-ray quants during high levels emission of solar active regions.

Observations of solar X-ray activity below 20 Angstroms

Observations of solar X-ray emission in the wavelength regions of 1–8 and 8–16 A have been made by Explorer 30 (NRL SOLRAD 8). The analog real-time records from this satellite show slowly varying changes of up to 40% in the 1–8 A region with a time scale of 1 or 2 minutes and of 20% in the 8–16 A region with a somewhat longer time scale. No fluctuations of more than 5–10% are observed within a time scale of 1 second, the highest time resolution of the satellite X-ray photometers.

X-ray photometers for aircraft generator brushes

The use of X-rays as a method of nondestructive quantitative chemical analysis is discussed. Two instruments designed for the measurement of barium fluoride treatment in aircraft generator brushes are described. Other applications of these instruments can be deduced from the method of analysis reviewed in the article.

Quantitative Analysis of Carbon Brush Treatments Using X-Ray Photometer Absorption Method [includes discussion

Quantitative Analysis of Carbon Brush Treatments Using X-Ray Photometer Absorption Method [includes discussion

X-ray Photometer for Chemical Analysis of Solids, Liquids or Gases

X-ray Photometer for Chemical Analysis of Solids, Liquids or Gases