RESUMO
We have developed narrow-bandpass MoSi/Si multilayer mirrors for a Japanese sounding-rocket program. A high spectral resolution lambda/Deltalambda exceeding 40 was achieved by a two-mirror telescope with a multilayer coating. The single telescope had two bandpasses in the extreme-UV range for detecting a coronal high-velocity flow; the wavelength at peak reflectance (hereafter peak wavelength) in one of the bandpasses was 210.2 A, situated on the blue side of the target's Fe XIV 211.3-A coronal emission line, and the peak wavelength in the other was 213.3 A on the red side. A high uniformity in a peak wavelength of less than 1 A was achieved over a primary (secondary) mirror surface 158 (96) mm in diameter. The ratio of the reflectance for the Fe XIV line at 211 A to that for an intense He II line as a contaminant at 304 A in the telescope system became 2 x 10(5) owing to a wave trap consisting of a single Si layer on the MoSi/Si multilayer. The narrow-bandpass (approximately 5-A) telescope was launched on 31 January 1998 by sounding rocket S520CN-22, and images of the whole-Sun corona at Fe XIV 211 A were successfully obtained.
RESUMO
Multilayer mirrors with a system wavelength resolution (lambda/Dlambda) as high as 30-50 are required for the diagnostics of cosmic plasmas with temperatures of 1-20 MK. Such a high wavelength resolution can be realized by increasing the number of layer pairs contributing to the reflectance, by selecting less-absorbing materials for both the reflector and the spacer, and by decreasing the thickness of the reflector. We have fabricated a multilayer mirror tuned to 284 A with a silicon carbide reflector (20% thickness of the layer period) and an aluminum spacer and achieved lambda/Dlambda ~26.8 with a peak reflectivity of ~13.0%. This wavelength resolution is close to the value obtained with a numerical simulation and is considerably higher than the value obtained with the conventional Mo/Si multilayer.
