314 mm2 Hexagonal Double-Sided Spiral Silicon Drift Detector for Soft X-Ray Detection Based on Ultra-Pure High Resistance Silicon

An X-ray pulsar is a remnant of massive star evolution, collapse, and supernova explosions. It has an extremely stable spin cycle and is known as the most accurate astronomical clock in the natural world. It presents high-precision navigational information, such as the location, speed, time, and attitude, which are used in deep space exploration and interstellar flight, such as the X-ray pulsar navigation (XPNAV). However, the energy of the X-ray from the pulsar is very low and its signal is very weak; this X-ray is known as the soft X-ray. In the low and medium energy radiation spectroscopy, the semiconductor detectors, especially the silicon drift detectors (SDD), achieve the best energy resolution. In this study, a 314 mm2 and a 600 mm2 double-sided spiral hexagonal silicon drift detector (DSSH-SDD) single cell for the pulsar soft X-ray detection is analyzed based on ultra-pure high-resistance silicon. The DSSH-SDD device is fabricated using ultra-pure high-resistivity silicon substrates patterned with ion-implanted electrodes. This study proposes a model capable of reaching a large area of 314 mm2 or 600 mm2 single cell and maintaining an optimal drift electric field. The design, modeling, 3D simulation, and the fabrication of the model are performed to analyze the physical performance of the DSSH-SDD. The electrical characteristics of the as-processed SDD chips, including leakage current, anode capacitance, and the spiral resistor current under the positive and negative biases are measured, and the energy resolution test is performed at the Tsinghua University. The energy resolution is an important indicator of the detector and is often expressed by full width at half maximum (FWHM). The results obtained in this study can be applied in the future for novel, flexible, large-area, high-resolution ionizing radiation detection systems capable of providing quantitative and real-time information of the relative position of spacecraft and pulsars through the pulsar X-ray radiation.

Coincidence Detection of EELS and EDX Spectral Events in the Electron Microscope

Recent advances in the development of electron and X-ray detectors have opened up the possibility to detect single events from which its time of arrival can be determined with nanosecond resolution. This allows observing time correlations between electrons and X-rays in the transmission electron microscope. In this work, a novel setup is described which measures individual events using a silicon drift detector and digital pulse processor for the X-rays and a Timepix3 detector for the electrons. This setup enables recording time correlation between both event streams while at the same time preserving the complete conventional electron energy loss (EELS) and energy dispersive X-ray (EDX) signal. We show that the added coincidence information improves the sensitivity for detecting trace elements in a matrix as compared to conventional EELS and EDX. Furthermore, the method allows the determination of the collection efficiencies without the use of a reference sample and can subtract the background signal for EELS and EDX without any prior knowledge of the background shape and without pre-edge fitting region. We discuss limitations in time resolution arising due to specificities of the silicon drift detector and discuss ways to further improve this aspect.

Elementary Analysis of Nail Polishes

Brazil is considered the 4th largest CT&F Market in the world. In 2017, the country earned R$ 102.5 billion, which means an increase of 3.2% over the year 2016. According to Associação Brasileira da Indústria de Higiene Pessoal, Perfumaria e Cosméticos (ABIHPEC), this information is provided by Strategic Research Institute for Consumer Markets, the Euromonitor. The composition of cosmetics produced should be in accordance with the recommendations presented in ANVISA RDC Resolution No. 83 of June, 2016. Prohibited elements in the RDC Resolution No. 83 are Cl, Ni, As, Be, Cd, Cr, I, P, Pb, Hg, Se, Zr, Co, Te, Tl and radioactive substances. The main purpose of this work was to characterize some nail polishes using EDXRF method. The analyses were made using EDXRF method at the Laboratory of Applied Nuclear Physics of the UTFPR. The AMPTEK portable X-ray equipment is composed of mini X-ray tube, model MINI X, with Ag and Au targets, as well as silicon drift detector, SDD-123 model. Qualitative analyses indicate Na, Mg, Al, Si, P, Na, S, Cl, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ba and Bi elements in the nail polishes analyzed. Some prohibited elements such as Cl, Ni and P were presents in nail polishes. It is shows that EDXRF method is very efficient in detecting the chemical elements present in these samples. Besides, these results enable to compare elements presents in sample and recommendation stablish in Resolution No. 83.