WITCH: a recoil spectrometer for weak interaction and nuclear physics studies

An experimental set-up is described for the precise measurement of the recoil energy spectrum of the daughter ions from nuclear beta decay. The experiment is called WITCH, short for Weak Interaction Trap for CHarged particles, and is set up at the ISOLDE facility at CERN. The principle of the experiment and its realization are explained as well as the main physics goal. A cloud of radioactive ions stored in a Penning trap serves as the source for the WITCH experiment, leading to the minimization of scattering and energy loss of the decay products. The energy spectrum of the recoiling daughter ions from the $\beta$--decays in this ion cloud will be measured with a retardation spectrometer. The principal aim of the WITCH experiment is to study the electroweak interaction by determining the beta--neutrino angular correlation in nuclear $\beta$--decay from the shape of this recoil energy spectrum. This will be the first time that the recoil energy spectrum of the daughter ions from $\beta$--decay can be measured for a wide variety of isotopes, independent of their specific properties

THE DEVELOPMENT OF A FAMILY OF LIGHTWEIGHT AND WIDE SWATH UAV CAMERA SYSTEMS AROUND AN INNOVATIVE DUAL-SENSOR ON-SINGLE-CHIP DETECTOR

Together with a Belgian industrial consortium VITO has developed the lightweight camera system MEDUSA. It combines high spatial resolution with a wide swath to support missions for large scale mapping and disaster monitoring applications. MEDUSA has been designed to be operated on a solar-powered unmanned aerial vehicle flying in the stratosphere. The camera system contains a custom designed CMOS imager with 2 sensors (each having 10000 × 1200 pixels) on 1 chip. One sensor is panchromatic, one is equipped with colour filters. The MEDUSA flight model camera has passed an extensive test campaign and is ready to conduct its maiden flight. First airborne test flights with an engineering model version of the camera have been executed to validate the functionality and the performance of the camera. An image stitching work flow has been developed in order to generate an image composite in near real time of the acquired images. The unique properties of the dual-sensor-on-single-chip detector triggered the development of 2 new camera designs which are currently in preparation. MEDUSA-low is a modified camera system optimised for compatibility with more conventional UAV systems with a payload capacity of 5–10 kg flying at an altitude around 1 km. Its camera acquires both panchromatic and colour images. The MEDUSA geospectral camera is an innovative hyperspectral imager which is equipped with a spatially varying spectral filter installed in front of one of the two sensors. It acquires both hyperspectral and broad band high spatial resolution image data from one and the same camera

A SPATIO-SPECTRAL CAMERA FOR HIGH RESOLUTION HYPERSPECTRAL IMAGING

Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600–900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475–925 nm), and we discuss future work

COMPACT HYPERSPECTRAL IMAGING SYSTEM (COSI) FOR SMALL REMOTELY PILOTED AIRCRAFT SYSTEMS (RPAS) – SYSTEM OVERVIEW AND FIRST PERFORMANCE EVALUATION RESULTS

This paper gives an overview of the new COmpact hyperSpectral Imaging (COSI) system recently developed at the Flemish Institute for Technological Research (VITO, Belgium) and suitable for remotely piloted aircraft systems. A hyperspectral dataset captured from a multirotor platform over a strawberry field is presented and explored in order to assess spectral bands co-registration quality. Thanks to application of line based interference filters deposited directly on the detector wafer the COSI camera is compact and lightweight (total mass of 500g), and captures 72 narrow (FWHM: 5nm to 10 nm) bands in the spectral range of 600-900 nm. Covering the region of red edge (680 nm to 730 nm) allows for deriving plant chlorophyll content, biomass and hydric status indicators, making the camera suitable for agriculture purposes. Additionally to the orthorectified hypercube digital terrain model can be derived enabling various analyses requiring object height, e.g. plant height in vegetation growth monitoring. Geometric data quality assessment proves that the COSI camera and the dedicated data processing chain are capable to deliver very high resolution data (centimetre level) where spectral information can be correctly derived. Obtained results are comparable or better than results reported in similar studies for an alternative system based on the Fabry–Pérot interferometer

Search for right-handed currents in the β±\beta^{\pm} decay of 118/Sb^{118}/Sb

We report on a recent experiment searching for right-handed currents in the /sup 118/Sb nuclear beta -decay. The correlation between the spin polarization and the beta -emission asymmetry of the positrons from the /sup 118/Sb decay is sensitive to the helicity structure of the weak interaction. A precision measurement of this correlation improves the limit on right-handed currents in beta -decay. (7 refs)