Sensitive Bolometric Detection of Atomic Hydrogen Fluxes

We developed a sensitive device to detect atomic hydrogen fluxes. The device is based on a measurement of the heating due to forced recombination of the atoms in the flux. We found that 60±10 % of the recombination heat is collected by the detector. The DC noise equivalent (1σ) flux Φ is 6×1010 at/s at a bandwidth of 0.4 Hz and a dynamic range of 1000 (Φmax=6×1013 at/s). The device may be used at ambient temperatures below 450 mK. We discuss possible improvements of the design.