I. Brandys - Academia.edu (original) (raw)

Papers by I. Brandys

2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009

Simultaneous PET-MR scanners are being developed for whole body imaging. These systems require co... more Simultaneous PET-MR scanners are being developed for whole body imaging. These systems require compact and MR compatible readout for the PET component. Another important modification is the geometry of the PET scanner which is determined by space constraints imposed by the surrounding MR scanner. The maximal radius of the PET scanner is limited and it becomes difficult to insert end shielding. The aim of this study is to determine the effect of modified geometry and reduced shielding on the PET performance with regards to spatial resolution, singles, trues, scatter and random coincidences. Materials and methods: All data were simulated using the GATE Monte Carlo simulation tool. The reference system for the simulation was a state of the art PET-CT scanner (Gemini TF scanner with LYSO crystals Philips Medical systems). This system has a diameter of 90 cm and end shields with an inner diameter of 70 cm. The energy resolution of the system is 12 % and based on this system a whole body ...

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2019

The virtual point detector (VPD) is a useful concept, which is used to simplify the calibration a... more The virtual point detector (VPD) is a useful concept, which is used to simplify the calibration and usage of radiation detectors. Investigation and validation of the VPD concept for a variety of NaI(Tl) scintillation detectors' geometrical dimensions and incident photon energies is presented. Monte Carlo calculations were performed in order to find the correlation between the VPD position and the detector dimensions. A general formula was found, describing the dependence of the VPD position on cylindrical detector's radius, attenuation coefficient and photon energies. The expression was found to be valid to 8% error relative to simulation data, for a large parameter range.

Journal of Nuclear Engineering and Radiation Science, 2017

Volume 11: Nano and Micro Materials, Devices and Systems; Microsystems Integration, 2011

ABSTRACT

IEEE Transactions on Nuclear Science, 2008

Theoretical optimization of a copper-water negative inclination heat pipe with internal composite... more Theoretical optimization of a copper-water negative inclination heat pipe with internal composite wick structure had been performed, regarding a new introduced parameter: the ratio between the coarse mesh wraps and the fine mesh wraps of the composite wick. Since in many cases, the design of a heat pipe matches specific thermal requirements and physical limitations, this work demonstrates the optimization of a 1m length, 8mm internal diameter heat pipe without an adiabatic section, at a negative inclination angle of -10o. The optimization is based on a new introduced parameter, LR: the ratio between the coarse mesh wraps and the fine mesh wraps. Keywords—Heat pipe, inclination, optimization, ratio.

EXPERIMENTAL HEAT TRANSFER SPECTRUM SHIFT PREVENTION OF A PORTABLE RADIATION SPECTROMETRY SYSTEM, 2011

Each radioactive material has its unique energy signature (spectrum). Spectrum shift during measu... more Each radioactive material has its unique energy signature (spectrum). Spectrum shift during measurements is a well know phenomenon which occurs due to environmental temperature changes which affect the electronics, and can lead to misidentification of the radioactive material. We developed a new portable spectroscopy workstation based on Digital Signal Processing (DSP) technology, which includes an analog circuit, a Multi Channel Analyzer (MCA), 7 power suppliers and a laptop. The designed system, to which wide range of radioactive detectors can be attached, uses to identify a sampled radioactive material according to its spectrum. In order to prevent the spectrum shift phenomena, both natural and forced convection heat transfer experiments were carried out. Few configurations were tested during these experiments whose results yielded the final electronic packaging configuration of the system as well as the definition of the stabilization time of the system.

Ieee Nuclear Science Symposium Conference Record Nuclear Science Symposium, 2009

Fast deployment, real time Environmental Radiation Monitoring System (ERMS), developed to meet pr... more Fast deployment, real time Environmental Radiation Monitoring System (ERMS), developed to meet pre and post radiological event necessities. The full system enables online environmental and radiation data transfer to multiple clients from a variety of sensor&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#x27;s types, e.g. radiation gamma field, wind direction and speed, assembled on a fast deployment monitoring station. The complete system enables temporal and spatial analysis

An Integrated approach for multi purpose fast deployment Environmental Radiation Monitoring System, 2009

Fast deployment, real time Environmental Radiation Monitoring System (ERMS), developed to meet pr... more Fast deployment, real time Environmental Radiation Monitoring System (ERMS), developed to meet pre and post radiological event necessities. The full system enables online environmental and radiation data transfer to multiple clients from a variety of sensor's types, e.g. radiation gamma field, wind direction and speed, assembled on a fast deployment monitoring station. The complete system enables temporal and spatial analysis for radiation safety and post event risk analysis.

The dependence of the virtual point detector on the scintillation detector dimensions, 2019

Small Size Integrated CsI(Tl) Spectrometer Efficiency and Properties Dependence on Temperature, 2008

Small-sized radiation scintillation detectors have been extensively developed for portable radiat... more Small-sized radiation scintillation detectors have been extensively developed for portable radiation survey systems, for a variety of applications. The CsI(Tl) capacity to discriminate the energy lines of a gamma-radiation source makes these detectors suitable for personal detection and spectrometry. Additional advantages are their miniature electronics and operation at room temperature. However, it is essential to inspect their efficiency, sensitivity and stability under the practical range of the environmental conditions expected during operation. The aim of this research is to study the changes in the response of a CsI(Tl) detector, 22 mm in diameter and 25 mm long, in the full range of operation temperatures , from 20 C to 60 C. Results show that the photo-peak efficiency for the Cs-137 gamma-line remains constant, even though the peak center channel is shifted as function of the detector temperature. The peak spectral resolution was also analyzed in the same temperature range and was found to be around 8%. Since the photopeak efficiency has been constant over the entire tested temperature range, the CsI(Tl) detector is a suitable spectrometry detector for environmental operations. Index Terms-CsI(Tl), gamma-ray spectrometry, inorganic scin-tillation detector, temperature dependence.

Integrated Blast Resistance Model of Nuclear Power Plant Auxiliary Facilities, 2017

Standards, guidelines, manuals, and researches refer mainly to the required protection of a nucle... more Standards, guidelines, manuals, and researches refer mainly to the required protection of a nuclear power plant (NPP) containment structure (where the reactor's vessel is located) against different internal and external extreme events. However, there is no consideration regarding the man-made extreme event of external explosion resulting from air bomb or cruise missile. A novel integrated blast resistance model (IBRM) of NPP's reinforced concrete (RC) auxiliary facilities due to an external above ground explosion based on two components is suggested. The first is structural dynamic response analysis to the positive phase of an external explosion based on the single degree-of-freedom (SDOF) method combined with spalling and breaching empirical correlations. The second is in-structure shock analysis, resulting from direct-induced ground shock and air-induced ground shock. As a case study, the resistance of Westinghouse commercial NPP AP1000 control room, including a representative equipment, to an external above ground blast loading of Scud B-100 missile at various standoff distances ranging from 250 m (far range) till contact, was analyzed. The structure's damage level is based on its front wall supports' angle of rotation and the ductility ratio (dynamic versus elastic mid-span displacement ratio). Due to the lack of specific structural damage demands and equipment's dynamic capacities, common protective structures standards and manuals are used while requiring that no spalling or breaching shall occur in the control room while it remains in the elastic regime. The engineering systems and equipments' spectral motions should be less than their capacity. The integrated blast resistance model (IBRM) of the structure and its equipment may be used in wider researches concerning other NPP's auxiliary facilities and systems based upon their specifications.