Ultra-stable implanted 83Rb/83mKr electron sources for the energy scale monitoring in the KATRIN experiment

The KATRIN experiment aims at the direct model-independent determination of the average electron neutrino mass via the measurement of the endpoint region of the tritium beta decay spectrum. The electron spectrometer of the MAC-E filter type is used, requiring very high stability of the electric filtering potential. This work proves the feasibility of implanted 83Rb/83mKr calibration electron sources which will be utilised in the additional monitor spectrometer sharing the high voltage with the main spectrometer of KATRIN. The source employs conversion electrons of 83mKr which is continuously generated by 83Rb. The K-32 conversion line (kinetic energy of 17.8 keV, natural line width of 2.7 eV) is shown to fulfill the KATRIN requirement of the relative energy stability of +/-1.6 ppm/month. The sources will serve as a standard tool for continuous monitoring of KATRIN's energy scale stability with sub-ppm precision. They may also be used in other applications where the precise conversion lines can be separated from the low energy spectrum caused by the electron inelastic scattering in the substrate.Comment: 30 pages, 10 figures, 1 table, minor revision of the preprint, accepted by JINST on 5.2.201

Energy sensitive X-ray radiography for the non-destructive inspection of historical paintings

The technical composition of painted artworks is usually very complex and they belong to the most sophisticated cultural heritage artefacts. In the field of their inspection there is a rising demand for the non-destructive imaging and analytical methods which are able to reveal the inner composition of investigated objects. Several non-invasive methods based on the interaction of ionizing radiation with the matter have been successfully utilized during the last decades. These methods can be divided into two main groups. The better known are transmission methods (e.g. classical X-ray radiography) the less-used are emission methods (e.g. X-ray fluorescence imaging). The quality of the obtained image is highly dependent on the imaging characteristics of the used detector. The presently used ones (CCD cameras and CMOS sensors) create the image from analogue signal by the charge integration. This image is usually degraded by the presence of noise. This complication is exceeded by novel pixel detectors of Medipix family based on single particle digital counting. Furthermore these devices offer very high contrast (in principle unlimited) in the obtained image. The image can be acquired with spatial resolution better than one micrometer. Another advantage of these detectors is their ability to directly measure the energy of incident particles. This feature can be used for energy sensitive X-ray radiography (i.e. multi-channel images) and X-ray fluorescence mapping of the surface elemental composition. For the purposes of this work the laboratory ALMA in Prague prepared several multilayer samples of paints using different pigments. The results of mentioned methods applied on the test samples are summarized in this article. The first goal of these measurements is to build a comprehensive methodology for the application of these procedures in the laboratory