This paper describes an application of infrared light-induced de-polarization applied on a polarized CdZnTe detector working under high radiation fluxes. We newly demonstrate the influence of a high flux of X-rays and simultaneous 1200-nm LED illumination on the spectroscopic properties of a CdZnTe detector. CdZnTe detectors operating under high radiation fluxes usually suffer from the polarization effect, which occurs due to a screening of the internal electric field by a positive space charge caused by photogenerated holes trapped at a deep level. Polarization results in the degradation of detector charge collection efficiency. We studied the spectroscopic behavior of CdZnTe under various X-ray fluxes ranging between 5×105 and 8×106 photons per mm2 per second. It was observed that polarization occurs at an X-ray flux higher than 3×106 mm−2·s−1. Using simultaneous illumination of the detector by a de-polarizing LED at 1200 nm, it was possible to recover X-ray spectra originally deformed by the polarization effect.
The element distribution in the fruit body of a wood-rotting fungus was studied. Samples of Fomes fomentarius were collected in nature, together with bark and a piece of substrate wood. For PIXE analysis, slices were cut from the fruit body. The slices were analyzed using a proton beam at many points from the fruit body surface to the core, or across the fruit-substrate interface. The analysis was performed with an external proton beam in a low-pressure nitrogen atmosphere; 9-12 elements heavier than silicon were found above the limit of quantitation. Manganese showed interesting systematic behavior. The suitability and usefulness of PIXE analysis for studying the distribution of heavy elements in fruit bodies of wood-rotting fungi are discussed.
Knowledge of beam fluence has a crucial role in quantitative particle‐induced X‐ray emission analysis. In some situations, a direct measurement of the beam charge on the target is either impossible or impractical. In such cases, indirect determination of the beam fluence can utilise the characteristic X‐ray of argon or other gases, which was being kept at a stable low partial pressure in the vicinity of the analysed sample. As the X‐ray signal of argon depends on the total charge, it can be used to quantify the charge. This paper describes the experimental design, the hardware and software modules that we created, the validation of the method, the application of the method during elemental analyses of fragile philatelic samples with overprints, and the lessons learned. Copyright © 2012 John Wiley & Sons, Ltd.
We have investigated the magnetic properties of carbon powders which consist of nanodisks, nanocones, and a small fraction of carbon-black particles. Magnetization measurements were carried out using a superconducting quantum interference device in magnetic fields −5 < µ 0 H < 5 T for temperatures in the range 2 ≤ T < 350 K. Measurements of the magnetization M versus temperature T and magnetic field µ 0 H for these carbon samples show diamagnetism and paramagetism with an additional ferromagnetic contribution. The ferromagnetic magnetization is in agreement with the calculated magnetization from Fe impurities as determined by the particle-induced x-ray emission method (< 75 µg/g). Magnetization measurements in weak magnetic fields show thermal hysteresis, and for strong fields the magnetization M decreases as M ∼ aT −α with α < 1, which is slower than the Curie law (α = 1), when the temperature increases. The magnetization M versus magnetic field µ 0 H shows paramagnetic free-spin S = 1 2 and 3 2 behaviors for temperatures T = 2 K and 15 ≤ T ≤ 50K, respectively. A tendency for localization of electrons was found by electron spin resonance when the temperature T decreases (2 < T < 40 K). The magnetic properties in these carbon cone and disk powder samples are more complex than a free-spin model predicts, which is apparently valid only for the temperature T = 2 K.2
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.