Source Of Soft X-ray Radiation Research Articles

New developments in soft X-ray monochromators for third generation synchrotron radiation sources

The advent of third generation synchrotron soft X-ray radiation sources has opened up many new opportunities for the use of spectroscopy and microscopy to study the structure of complex materials. The ultra-high brightness of these sources offers the possibility of combining the two techniques so that the spectroscopy of microscopic areas of a material may be studied (spectromicroscopy), and in addition offers tremendous flux and resolution enhancements for traditional macroscopic surface studies. The optical properties of both bending magnet and undulator sources for use in third generation soft X-ray sources offer significant possibilities for improving the performance of optical systems compared with traditional designs. We will describe two recent such advances in beamline optical system design at the advanced light source (ALS) and review the performance of a current generation of undulator based beamlines at the ALS.

Accreting, Isolated Neutron Stars. III. Preheating of Infalling Gas and Cometary H II Regions

view Abstract Citations (41) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Accreting, Isolated Neutron Stars. III. Preheating of Infalling Gas and Cometary H II Regions Blaes, Omer ; Warren, Orlando ; Madau, Piero Abstract Nearby, isolated, old neutron stars (IONSs) accreting interstellar material might be detectable as sources of UV and soft X-ray radiation. We investigate the interaction between this radiation field and the surrounding medium, assumed to consist of purely hydrogen and helium. This interaction results in a cometary H II region around the star which we model in detail by including all the relevant time-dependent ionization, recombination, heating, and cooling processes. We find that preheating of the ambient gas to temperatures higher than 104 K may significantly quench the accretion rate onto these neutron stars, thereby reducing the IONS number counts in the EUV and soft X-ray bands predicted by previous investigations. However, the reprocessing of hard radiation by the surrounding H II regions may enhance the detectability of IONSs at optical wavelengths. Searches for nearby accreting IONSs are currently being undertaken. Publication: The Astrophysical Journal Pub Date: November 1995 DOI: 10.1086/176488 Bibcode: 1995ApJ...454..370B Keywords: ACCRETION; ACCRETION DISKS; ISM: H II REGIONS; STARS: NEUTRON; ULTRAVIOLET: STARS; X-RAYS: STARS full text sources ADS | data products SIMBAD (1)

A practical self-healing mercury target for efficient generation of soft x-ray radiation

We have developed a self-healing mercury-wetted target as a practical source of soft x-ray radiation for photoexciting extreme ultraviolet lasers. A threaded rod, rotating in a pool of mercury, demonstrates a soft x-ray conversion efficiency similar to that of expendable gold-coated targets in synchronous photopumping of a photoionization Xe2+ laser at 109 nm. Surfaces self-heal or are continuously regenerated by rewetting, while mercury debris is removed by evaporation from the target chamber walls and optics. Long target lifetime and self-cleaning performance of the new target system are attractive features in future high-repetition-rate, high-throughput applications for photopumping of extreme ultraviolet or soft x-ray lasers, and more generally as incoherent sources for soft x-ray lithography and spectroscopy.

Scientific program of the advanced light source at LBL

Abstract Construction of the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is nearing completion, with operation as a US Department of Energy national user facility scheduled to begin in the spring of 1993. Based on a low-emittance, 1.5 GeV electron storage ring with ten long straight sections available for insertion devices and, initially, 24 bend-magnet ports, the ALS will be a third-generation source of soft X-ray and ultraviolet (collectively, the XUV) synchrotron radiation. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. The ability to exploit the high spectral brightness of the ALS was the main criterion for PRT selection. In the XUV spectral regions served by the ALS, a major benefit of high brightness will be the ability to achieve spatial resolution in the neighborhood of 200 A in X-ray microscopy and holography and in spatially resolved spectroscopy. Other beneficiaries of high brightness include very-high-resolution spectroscopy, spectroscopy of dilute species, diffraction from very small samples, and time-resolved spectroscopy and diffraction.

Diffraction-limited soft x-ray projection lithography with a laser plasma source

A laser plasma source of extreme ultraviolet and soft x-ray radiation has been used to print diffraction-limited features using soft x-ray projection lithography. A spherical condenser optic, a Si/Ge transmissive mask and a Mo/Si multilayer-coated Schwarzschild objective having 20:1 reduction ratio were employed to pattern selected single-layer and trilevel resists. At a numerical aperture of 0.12, a 0.1-μm line and space pattern is clearly delineated and weak modulation is observed for the analogous 0.05-μm pattern.

Phobos 2 mission: Observations of the solar soft x-ray radiation

This paper discusses the results of the long-term measurements of soft X-ray solar radiation during the Phobos 2 mission to Mars. There are variations in the minimal daily background flux of the X-ray solar radiation over 250 days of the mission, and it is shown that the presence of X-ray precursors is not a necessary and typical characteristic of a solar flare ; estimates are made of the heights of soft X-ray radiation sources, from concurrent observations of solar flares from the spacecraft and the Earth ; specific features of X-ray sounding of the Martian atmosphere are considered.

Generation of the highest possible concentrations of theF2color centers in lithium fluoride crystals by a laser-plasma source of soft x-ray radiation

A new method was developed for coloration of crystals by low-energy soft x-ray photons. Crystals of LiF with the F2 color centers in concentrations up to 1019 cm−3 and a colored layer 4 μm thick were obtained.

The Daresbury Synchrotron Radiation Source

The Daresbury Synchrotron Radiation Source consists of an electron storage ring designed to operate at an energy of 2GeV and with a stored current of 330mA. The dipole magnets have a bending radius of 5.56m and a field of 1.2T, which results in a λc of 3.88Å. A 5T wiggler is also in operation which shifts λc to 0.93Å. Recently an undulator magnet has been inserted into the storage ring and will be used to provide an intense source of VUV and soft X-ray radiation. Eight beamlines are now in routine operation and provide radiation for 23 experimental stations. The experimental activities encompass a wide range of research in chemistry, physics, biology and material science, and use radiation from the infrared to the hard X-ray. In addition, time-resolved spectroscopy is undertaken with the storage ring operating in single bunch mode. Recent highlights of the VUV research in photochemistry, photophysics and surface science are described to illustrate the various experimental techniques being applied and to provide an outline of the scientific programme. A summary is given of selected X-ray work.