Solar flux and spectrum measurements in the EUV spectral region on board CORONAS-I satellite

There are presented data on solar emission variations in the extreme ultraviolet range (lambda < 130 nm) which were obtained on board the CORONAS-I satellite during the solar activity minimum epoch in 1994. Based on the thermoluminescent technique, the measurements were performed using the SUFR (Solar Ultraviolet Radiometer) equipment for recording the solar emission flux at lambda < 130 nm. The technique provides absolute measurements. The intensity of the He II 30.4 nm line emission was also measured on board the CORONAS by means of the Vacuum Ultraviolet Solar Spectrometer (VUSS), which uses gas-photoelectron energy and intensity analysis to register the spectrum. The characteristics of both devices are given, as well as calibration methods and the main results. The observation period may be characterized by a very low activity level. The solar flux in the region lambda < 130 nm was 7.5-8 erg cm(-2) s(-1), the L alpha line intensity was similar to (3.3-3.7) x 10(11) photon cm(-2) s(-1) and the He II (30.4 nm) line intensity was (6-7.5) x 10(9) photon cm(-2) s(-1). Intensive solar flares were not registered during the period of observation. During the flare of B4.5 X-ray class (30 June 1994, 01:08 UT), an increase of flux of similar to 15% was registered in the range lambda < 130 nm.