Radio-quiet neutron star Radio-quiet neutron star A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly x-rays and gamma rays. Most detected neutron stars are pulsars, and emit radio-frequency electromagnetic radiation. About 700 radio pulsars are listed in the Princeton catalog, and all but one emit radio waves at the 400 MHz and 1400 MHz frequencies. That exception is Geminga, which is radio quiet at frequencies above 100 MHz, but is a strong emitter of X-rays and gamma rays. In all,
Laser beam profiler centroid of a laser beam can be determined to sub-micrometre accuracy with a laser beam profiler. The laser beam profiler's effective aperture size is three orders of magnitude smaller than that of an iris. Consequently, the ability to define an optical path is 1000 times better when using beam profilers over irises. Applications that need microradian alignment accuracies include earth-to-space communications, earth-to-space ladar, master oscillator to power oscillator alignment, and multi-pass amplifiers. Experimental laser systems benefit from the use of multiple laser beam profilers to characterize the pump beam, the output beam, and the beam shape at intermediate locations in