AAS 201st Meeting, January, 2003
Session 82. Planning for Future Missions: Radio to X-Ray
Poster, Wednesday, January 8, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[82.11] Windowless Far-Ultraviolet Electron Impact Calibration Lamp

K. France, S. R. McCandliss, R. Pelton (JHU)

We present preliminary results from a windowless calibration lamp for determining wavelength solutions and detector flat-fielding at far-ultraviolet wavelengths. This lamp produces free electrons from a filament, accelerating them toward a tungsten target by an applied voltage (~200 - 2000 V). An emission line spectrum is produced by electrons impacting the residual gas molecules present and continuous emission is produced by bremsstrahlung as the electrons collide with the target. The emission line spectrum can be modified to provide a rich wavelength coverage by introducing different species, and spectra of H2, N2, O2, CO2, HD, and Ar have been measured at modest spectral resolution (1 Å) across the far-UV bandpass (900 - 1400 Å). The long wavelength tail of the x-ray bremsstrahlung continuum falling in this bandpass can be used to make detector flat-field measurements. The lamp is robust and compact, housed in a mini-conflat cube and operates at the ambient vacuum compatible with microchannel plate operation. It is scheduled to be tested on an upcoming sounding rocket flight. We present initial results of both electron impact and bremsstrahlung spectra and adaptability to space-based instrumentation.

This work is supported by NASA grant NAG5-5315 to The Johns Hopkins University.


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