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Article
Publication date: 1 January 2006

Khalil Arshak and Olga Korostynska

Combination of a number of sensors with different response parameters into sensor arrays would enhance the overall performance of the radiation detection system. This…

Abstract

Purpose

Combination of a number of sensors with different response parameters into sensor arrays would enhance the overall performance of the radiation detection system. This paper presents a conceptual approach to the development of sensor arrays system with instantaneous dose and dose rate readout. A dynamic selection of multiple sensors with various sensitivity and accuracy range is implemented by applying pattern recognition (PR) analysis, which maximizes measurement accuracy. A number of relevant PR methods are discussed.

Design/methodology/approach

Thick films based on NiO, ZnO, In2O3, CeO2, TiO2, CuO and CdO are the key sensing elements in the proposed approach. Pure and carbon‐doped metal oxides were screen‐printed on Si wafers to form pn‐heterojunctions. All devices were exposed to a disc‐type 137 Cs source with an activity of 370 kBq. The values of radiation damage of pn‐junctions were estimated from changes in their current‐voltage characteristics.

Findings

Sensors showed an increase in the values of current with the increase in radiation dose up to certain levels, exceeding these levels results in unstable dosimetric characteristics.

Originality/value

The sensitivity of metal oxide films to γ‐radiation exposure depends on their composition and thickness. Mixing the oxides in different proportions and the addition of conducting particles, such as carbon, alters films susceptibility to radiation. In particular, sensors based on such films have dose response characteristics with certain level of sensitivity and working dose range, conditioned by particular sensing material properties and the device structure.

Details

Sensor Review, vol. 26 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 March 2003

K. Arshak and O. Korostynska

Thin films of tellurium dioxide (TeO2) and indium oxide (In2O3) mixtures were investigated for γ‐radiation dosimetry purpose. Samples were fabricated using thermal vacuum…

Abstract

Thin films of tellurium dioxide (TeO2) and indium oxide (In2O3) mixtures were investigated for γ‐radiation dosimetry purpose. Samples were fabricated using thermal vacuum evaporation technique. The electrical properties of mixed oxides thin films [(TeO2)1−x(In2O3)x, where x=0 and 10 per cent by weight] and their changes under the influence of γ‐radiation were investigated. Samples with contacts having a planar structure showed increase in the values of current with the increase in radiation dose up to a certain dose level. Thin films in the form of pn‐junctions were fabricated with (TeO2)1−x(In2O3)x as p‐type material and sulphur as n‐type material. These pn‐junctions exhibited Zener diode behaviour. The current‐voltage characteristics for as‐deposited and γ‐irradiated samples were recorded. The level of response for all the fabricated devices was found to be highly dependent on the composition of the exposed material.

Details

Sensor Review, vol. 23 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 January 2008

K. Arshak, A. Arshak, E. Jafer, D. Waldern and J. Harris

To develop a wireless sensor micro‐systems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital…

2833

Abstract

Purpose

To develop a wireless sensor micro‐systems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital converter, embedded microcontroller unit (MCU), and RF communication modules. This has now become the focus of attention in many biomedical applications.

Design/methodology/approach

The system prototype consists of miniature FSK transceiver integrated with MCU in one small package, chip antenna, and capacitive interface circuitry based on Delta‐sigma modulator. At the base station side, an FSK receiver/transmitter is connected to another MCU unit, which send the received data or received instructions from a PC through a graphical user interface GUI. Industrial, scientific and medical band RF (433 MHz) was used to achieve half duplex communication between the two sides. A digital filtering has been used in the capacitive interface to reduce noise effects forming capacitance to digital converter. All the modules of the mixed signal system are integrated in a printed circuit board of size 22.46 × 20.168 mm.

Findings

An innovation circuits and system techniques for building advanced smart medical devices have been discussed. Low‐power consumption and high reliability are among the main criteria that must be given priority when designing such wirelessly powered microsystems. Switched capacitors readout circuits have been found to be suitable for pressure sensing low‐power applications.

Research limitations/implications

The presented wireless prototype needs a second phase of development that will lead to a further reduction in both size and power consumption. Currently, the main limitation of the RF system is the number of working hours according to the selected battery.

Practical implications

The developed system was found to be useful in terms of measuring pressure and temperature in a system of either slow or fast physical change. It would be a good idea to explore the system performance in human or animal trials.

Originality/value

This paper fulfils useful information for capacitive interface circuitries and presents a new short‐range wireless system that has different design features.

Details

Microelectronics International, vol. 25 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 December 2005

A. Arshak, K. Arshak, G. Lyons, D. Waldron, D. Morris, O. Korostynska and E. Jafer

Telemetry capsules have existed since the 1950s and were used to measure temperature, pH or pressure inside the gastrointestinal (GI) tract. It was hoped that these…

1430

Abstract

Purpose

Telemetry capsules have existed since the 1950s and were used to measure temperature, pH or pressure inside the gastrointestinal (GI) tract. It was hoped that these capsules would replace invasive techniques in the diagnosis of function disorders in the GI tract. However, problems such as signal loss and uncertainty of the pills position limited their use in a clinical setting. In this paper, a review of the capabilities of microelectromechanical systems (MEMS) for the fabrication of a wireless pressure sensor microsystem is presented.

Design/methodology/approach

The circuit requirements and methods of data transfer are examined. The available fabrication methods for MEMS sensors are also discussed and examples of wireless sensors are given. Finally, the drawbacks of using this technology are examined.

Findings

MEMS for use in wireless monitoring of pressure in the GI tract have been investigated. It has been shown that capacitive pressure sensors are particularly suitable for this purpose. Sensors fabricated for wireless continuous monitoring of pressure have been reviewed. Great progress, especially using surface micromachining, has been made in recent years. However, despite these advances, some challenges remain.

Originality/value

Provides a review of the capabilities of MEMS.

Details

Sensor Review, vol. 25 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 December 2002

K. Arshak and O. Korostynska

The effects of γ‐radiation on both the optical and the electrical properties of Tellurium dioxide (TeO2) thin films were investigated. TeO2 thin films were fabricated…

Abstract

The effects of γ‐radiation on both the optical and the electrical properties of Tellurium dioxide (TeO2) thin films were investigated. TeO2 thin films were fabricated using thermal vacuum deposition method. Samples were exposed to a 60Co γ‐radiation source with a dose rate of 6 Gy/min. Absorption spectra for TeO2 thin films were recorded and values of the optical band gap for as‐deposited and γ‐irradiated films were calculated. Sets of measurements based on Hall effect were carried out. From the data received the dependences of sheet resistance, density of charge carriers, mobility and Hall coefficient with radiation dose were determined.

Details

Microelectronics International, vol. 19 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 December 2004

K. Arshak, E. Jafer, G. Lyons, D. Morris and O. Korostynska

The development of a sensor microsystems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital converter…

2667

Abstract

The development of a sensor microsystems containing all the components of data acquisition system, such as sensors, signal‐conditioning circuits, analog‐digital converter, interface circuits and embedded microcontroller (MCU), has become the focus of attention in many biomedical applications. A review of the microsystems technology is presented in this paper, along with a discussion of the recent trends and challenges associated with its developments. A basic description of each sub‐system is also given. This includes the different front end, mixed analog‐digital, power management, and radio transmitter‐receiver circuits. These sub‐system designs are presented and discussed in a comparative study and final remarks are made. The performance of each sub‐system is assessed regarding many aspects related to the overall system performance.

Details

Microelectronics International, vol. 21 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 April 1994

K.I. Arshak, D. McDonagh, B.P. Mathur and A. Arshak

In this paper, simulation of topography effects in photolithography is examined using the two‐dimensional PC based simulator called SLITS (Simulation of Lithography on T

Abstract

In this paper, simulation of topography effects in photolithography is examined using the two‐dimensional PC based simulator called SLITS (Simulation of Lithography on Topographic Substrates). This program uses FEA software (in‐house written) to solve wave propagation in a photoresist layer and a modified String Algorithm for photoresist development. The simulated results illustrates the effect of topography on the latent and relief images.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 1 April 1994

B.P. Mathur, K.I. Arshak, D. Mc Donagh and A. Arshak

The dry development of a photoresist is modelled using the analytical solution of the Boltzmann equation. It is proposed that at very low pressure and in the presence of a…

Abstract

The dry development of a photoresist is modelled using the analytical solution of the Boltzmann equation. It is proposed that at very low pressure and in the presence of a magnetic field, the etch rate of the resist can be calculated by integrating the ion flux. The simulation results illustrates improvement in both microuniformity and macrouniformity when the resist is etched under these process conditions.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 1 April 2004

Khalil Arshak, Olga Korostynska and John Henry

Indium oxide (In2O3) and silicon oxide (SiO) mixtures in the form of thick films pn‐junctions were investigated for gamma radiation dosimetry purposes. Polymer pastes of In…

Abstract

Indium oxide (In2O3) and silicon oxide (SiO) mixtures in the form of thick films pn‐junctions were investigated for gamma radiation dosimetry purposes. Polymer pastes of In2O3 and SiO mixtures in various proportions were made of 92 wt per cent of functional material and 8 wt per cent of PVB, while ethyleneglycolmonobutylether was used as a solvent. Raman spectroscopy and X‐ray diffraction (XRD) of the films readily endorse the formation of a mixed silicon oxide and indium oxide coating. All devices were exposed to a disc‐type 137Cs source with an activity of 370 kBq. The IV characteristics for the samples were measured after each exposure dose. Results show that the current is increased with the increase in radiation dose to a certain level, exceeding this level resulted in unstable dosimetric characteristics and device damage. The performance parameters of the devices, such as sensitivity to γ‐radiation exposure and working dose region, were found to be highly dependant on the composition of the materials used.

Details

Microelectronics International, vol. 21 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 14 January 2014

Sari Lakkis, Rafic Younes, Yasser Alayli and Mohamad Sawan

This paper aims to give an overview about the state of the art and novel technologies used in gas sensing. It also discusses the miniaturization potential of some of these…

1486

Abstract

Purpose

This paper aims to give an overview about the state of the art and novel technologies used in gas sensing. It also discusses the miniaturization potential of some of these technologies in a comparative way.

Design/methodology/approach

In this article, the authors state the most of the methods used in gas sensing discuss their advantages and disadvantages and at last the authors discuss the ability of their miniaturization comparing between them in terms of their sensing parameters like sensitivity, selectivity and cost.

Findings

In this article, the authors will try to cover most of the important methods used in gas sensing and their recent developments. The authors will also discuss their miniaturization potential trying to find the best candidate among the different types for the aim of miniaturization.

Originality/value

In this article, the authors will review most of the methods used in gas sensing and discuss their miniaturization potential delimiting the research to a certain type of technology or application.

Details

Sensor Review, vol. 34 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

1 – 10 of 32