Sounding rocket measurement of the absolute solar EUV flux utilizing a silicon photodiode

Abstract

A newly developed stable and high quantum efficiency silicon photodiode was used to obtain an accurate measurement of the integrated absolute magnitude of the solar extreme ultraviolet photon flux in the spectral region between 50 and 800 Å. The detector was flown aboard a solar pointing sounding rocket launched from White Sands Missile Range in New Mexico on October 24, 1988. The adjusted daily 10.7‐cm solar radio flux and sunspot number were 168.4 and 121, respectively. The unattenuated absolute value of the solar EUV flux at 1 AU in the specified wavelength region was 6.81×1010 photons cm−2 s−1. Based on a nominal probable error of 7% for National Institute of Standards and Technology detector efficiency measurements in the 50‐ to 500‐Å region (5% on longer wavelength measurements between 500 and 1216 Å), and based on experimental errors associated with our rocket instrumentation and analysis, a conservative total error estimate of ∼14% is assigned to the absolute integral solar flux obtained.