963 resultados para SIGNAL AMPLIFICATION
Resumo:
Saturation of a low pump energy x-ray laser utilizing a transient inversion mechanism on the 3p-3s transition at 32.63 nm in Ne-like Ti has been demonstrated. A close to saturation amplification was simultaneously achieved for the 3d-3p, J=1-->1 transition at 30.15 nm. Small signal effective transient gain coefficients of g similar to 46 and similar to 35 cm(-1) and gain-length products of 16.7 and 16.9 for these lines were obtained. Experiments demonstrate that it is possible to achieve saturated laser action in a transient regime with Ne-like Ti for a pump energy as low as similar to 5 J.
Resumo:
We have carried out a survey of the Andromeda galaxy for unresolved microlensing (pixel lensing). We present a subset of four short timescale, high signal-to-noise microlensing candidates found by imposing severe selection criteria: the source flux variation exceeds the flux of an R = 21 magnitude star and the full width at half maximum timescale is less than 25 days. Remarkably, in three out of four cases, we have been able to measure or strongly constrain the Einstein crossing time of the event. One event, which lies projected on the M 31 bulge, is almost certainly due to a stellar lens in the bulge of M 31. The other three candidates can be explained either by stars in M 31 and M 32 or by MACHOs.
Resumo:
From measurements of spatial coherence and beam divergence of Ge soft x-ray laser at a far field, the x-ray laser beam has been characterized as a partially coherent Gaussian beam. Double-pass amplification will improve spatial and temporal coherence, spectral brightness and efficiency. Close to 100% geometrical coupling efficiency has been obtained in double pass amplification in Ge. Transient loss of feedback is attributed to mirror structure damage within the build-up time of the x-ray laser. Prospect for generation of coherent x-ray laser beam is discussed.
