RESUMEN
In this work, we report a method to observe soft X-ray radiographs at nanoscale of various kind of samples, biological and metallic, stored in a thin layer of lithium fluoride, employing scanning near-field optical microscopy with an optical resolution that reaches 50 nm. Lithium fluoride material works as a novel image detector for X-ray nano-radiographs, due to the fact that extreme ultraviolet radiation and soft X-rays efficiently produce stable point defects emitting optically stimulated visible luminescence in a thin surface layer. The bi-dimensional distribution of the so-created defects depends on the local nanostructure of the investigated sample.
Asunto(s)
Fluoruros , Compuestos de Litio , Microscopía de Sonda de Barrido , Radiografía , Cristalización , Microscopía Confocal , Microscopía Fluorescente , Nanotecnología/instrumentación , Nanotecnología/métodos , Olea/ultraestructura , Polen/ultraestructura , Radiografía/instrumentación , Radiografía/métodos , Rayos XRESUMEN
X-ray microradiographs of small biological objects, such as animals and plant materials at micrometric resolution, are currently performed by various methods, all of which are limited by the resolution or the dynamic range of the image detectors. Here a novel X-ray image detector is discussed, in which the previous limitations have been overcome. A film of lithium fluoride salt is used as a detector, in which the stored biological image is read by observing the optically stimulated visible luminescence of the active color centers, efficiently produced by the X-rays.
Asunto(s)
Microanálisis por Sonda Electrónica/instrumentación , Fluoruros/química , Compuestos de Litio/química , Microscopía Fluorescente/instrumentación , Nanotecnología/instrumentación , Radiografía/instrumentación , Alas de Animales/diagnóstico por imagen , Pantallas Intensificadoras de Rayos X , Animales , Cristalización/métodos , Dípteros , Microanálisis por Sonda Electrónica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Estudios de Factibilidad , Fluoruros/efectos de la radiación , Insectos , Compuestos de Litio/efectos de la radiación , Microscopía Fluorescente/métodos , Nanotecnología/métodos , Radiografía/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Rayos XRESUMEN
A small residual birefringence producing a retardation of 0.05 rad has been measured in silica windows mounted in a liquid helium cryostat. The effect is due to a uniaxial stress on the windows induced by the pressure difference between the helium reservoir and the vacuum jacket.
Asunto(s)
Artefactos , Helio/análisis , Helio/química , Ensayo de Materiales/instrumentación , Refractometría/instrumentación , Refrigeración/instrumentación , Manejo de Especímenes/instrumentación , Birrefringencia , Frío , Refractometría/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , VacioRESUMEN
This paper analyzes the operation of a particular class of polarization modulator, the oscillating stress plate, when it is used for making magnetic circular dichroism (MCD) measurements. In particular, precise calibration factors relating the MCD signal strength to the amplitude of the modulator stress are given. Also, construction and performance of a very simple and inexpensive modulator are described.