D. D. Glower

Bio: D. D. Glower is an academic researcher from Sandia National Laboratories. The author has contributed to research in topics: Dosimeter & Irradiation. The author has an hindex of 1, co-authored 1 publications receiving 19 citations.

Use of Ferroelectrics for Gamma-Ray Dosimetry

Abstract: A gamma-ray dosimeter employing a poled ferroelectric as the transducer element has been studied. Irradiation with gamma rays causes a release of charge by the ferroelectric element. The magnitude of the charge released has been determined experimentally to vary linearly with gamma-ray dose. The current in a shunting resistor with no external voltage applied varies linearly with gamma-ray dose rate. A constant of proportionality of 10-12 coul per rad (H2O) per cm2 of electroded ferroelectric surface has been measured for polycrystalline Pb(Zr.65 Ti.35)O3 + 1 w% Nb2O5 irradiated in the Sandia Pulsed Reactor. The contribution to the charge release from the neutron irradiation has been determined experimentally to be negligible. Irradiation in the 0.6 Mvp flash X-ray also produces a linear relationship between current and gamma-ray dose rate. A similar release of charge has been observed in poled ceramic barium titanate.

A Review of Semiconductor Based Ionising Radiation Sensors Used in Harsh Radiation Environments and Their Applications

Abstract: This article provides a review of semiconductor based ionising radiation sensors to measure accumulated dose and detect individual strikes of ionising particles. The measurement of ionising radiation (γ-ray, X-ray, high energy UV-ray and heavy ions, etc.) is essential in several critical reliability applications such as medical, aviation, space missions and high energy physics experiments considering safety and quality assurance. In the last few decades, numerous techniques based on semiconductor devices such as diodes, metal-oxide-semiconductor field-effect transistors (MOSFETs) and solid-state photomultipliers (SSPMs), etc., have been reported to estimate the absorbed dose of radiation with sensitivity varying by several orders of magnitude from μGy to MGy. In addition, the mitigation of soft errors in integrated circuits essentially requires detection of charged particle induced transients and digital bit-flips in storage elements. Depending on the particle energies, flux and the application requirements, several sensing solutions such as diodes, static random access memory (SRAM) and NAND flash, etc., are reported in the literature. This article goes through the evolution of radiation dosimeters and particle detectors implemented using semiconductor technologies and summarises the features with emphasis on their underlying principles and applications. In addition, this article performs a comparison of the different methodologies while mentioning their advantages and limitations.

Use of lithium niobate detector for measuring X-ray intensity in mammographic range

Abstract: A detector system that can measure X-ray intensity in the mammographic range of 22 to 36 kVp (equivalent photon energies of the beam between 11 and 15 keV) is presented. It consists of a lithium niobate detector and a high-sensitivity current-to-voltage converter.

Microcontrolled pyro-electric instrument for measuring X-ray intensity in mammography

Abstract: A novel instrument for measurement of X-ray intensity from mammography consists of a sensitive pyro-electric detector, a high-sensitivity, low-noise current-to-voltage converter, a microcontroller and a digital display. The heart of this device, and what makes it unique is the pyro-electric detector, which measures radiation by converting heat from absorbed incident X-rays into an electric current. This current is then converted to a voltage and digitised. The detector consists of a ferro-electric crystal; two types were tested; lithium tantalate and lithium niobate. X-ray measurement in mammography is challenging because of its relatively low photon energy range, from 11 keV to 15 keV equivalent mean energy, corresponding to a peak tube potential from 22 to 36 kV. Consequently, energy fluence rate or intensity is low compared with that of common diagnostic X-ray. The instrument is capable of measuring intensities as low as 0.25 mWm−2 with precision greater than 99%. Not only was the instrument capable of performing in the clinical environment, with high background electromagnetic interference and vibration, but its performance was not degraded after being subjected to 140 roentgen (3.6×10−2 C kg−2 air) as measured by piezo-electric (d33) or pyro-electric coefficients.