As part of the WFPC2 close-out calibrations, we examine the stability of the bandwidths of the narrow band and linear ramp filters. We measure the FWHM of the spots produced by VISFLAT exposures using linear ramp filters crossed with narrow band filters. We do this for eight different pairings of narrow band and linear ramp filters. We then compare results from 1995 and 2008, and find negligibl...

We report on the detection of four primordial galaxies candidates in the redshift range 4.55 ≤ z ≤ 4.76, as well as 4 other candidates in the range 4.12 ≤ z ≤ 4.32. These galaxies have been detected with the now common technique of the Lyman break, but with a very original instrumental setup, which allows the simultaneous detection on a single exposure of three narrow (FWHM ∼ 200 Å) bands. Depe...

The generation of isolated attosecond hard x-ray pulse has been studied under the enhanced self-amplified spontaneous emission (ESASE) scheme with the density and energy modulation of an electron bunch. It is demonstrated in simulation that an isolated attosecond hard x-ray pulse of a high contrast ratio can be produced by adjusting a driver laser wavelength and the energy distribution of an el...

A tunable mid-infrared continuous-wave (cw) spectroscopic source in the 3.4-4.5 micrometers region is reported, based on difference frequency generation (DFG) in a quasi-phase-matched periodically poled RbTiOAsO4 (PPRTA) crystal. DFG power levels of 10 microW were generated at approximately 4 micrometers in a 20-mm long PPRTA crystal by mixing two cw single-frequency Ti:Al2O3 lasers operating n...

The devitrification of initially amorphous Ni80B20 has been studied by x-ray-absorption spectroscopy as a function of the annealing temperature. It is found that the full width at half maximum ~FWHM! of the main absorption peak at '850 eV is sensitive to the degree of amorphization of the specimen. The initial FWHM of 2.51 eV for the homogeneous amorphous Ni80B20 decreases to a value of 2.12 eV...

Because of their increased sensitivity to spatially extended signals, cluster-size tests are widely used to detect changes and activations in brain images. However, when images are nonstationary, the cluster-size distribution varies depending on local smoothness. Clusters tend to be large in smooth regions, resulting in increased false positives, while in rough regions, clusters tend to be smal...

The energy scaling up of pulse postcompression is still an open issue. In this work we analyze the use of astigmatic focusing to improve the output pulses in a filamentation based postcompression setup. Unlike spherical conditions, astigmatic focusing enhances the output energy and the spectral broadening of the filament. This is due to the increase of critical power, allowing a considerable im...

2014 Energy distribution measurements on 20 keV beams of 12C-, 32S-, 127I-, Hand 160have shown no obvious differences between Hand 16Oon the one hand, which are believed to be produced in an adsorbed layer on the target, and 12C-, 32Sand 127Ion the other which are part of the target material. All spectra have a single peak and a FWHM of the order of 10-12 eV. The significance of the energy dist...

Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, Delft, 2629 JB, the Netherlands Time-of-flight Positron Emission Tomography (TOF-PET) and TOF-PET/MRI require scintillators with high light yield, short decay time, and short rise time in order to obtain high timing resolution. LSO:Ce and LYSO:Ce are commonly used. Ca co-doped LSO:Ce shows improved scintillation propertie...

We present a theory for a new type of optical spatial soliton that is based on the angle hole burning mechanism of photoisomerization in some polymers. We predict that the photoisomerization nonlinearity can support steady-state dark and bright spatial solitons in the polymer. We also discuss the dependence of the FWHM of the spatial soliton on wavelengths of the background beams and on the rat...