Thermoluminescence as a Research Tool to Investigate Luminescence Mechanisms.

Thermally stimulated luminescence (TSL) is known as a technique used in radiation dosimetry and dating. However, since the luminescence is very sensitive to the defects in a solid, it can also be used in material research. In this review, it is shown how TSL can be used as a research tool to investigate luminescent characteristics and underlying luminescent mechanisms.

Charge Carrier Trapping Processes in REOS (RE = La, Gd, Y, and Lu).

Two different charge carrier trapping processes have been investigated in REOS:Ln (RE = La, Gd, Y, and Lu; Ln = Ce, Pr, and Tb) and REOS:M (M = Ti and Eu). Cerium, praseodymium and terbium act as recombination centers and hole trapping centers while host intrinsic defects provide the electron trap. The captured electrons released from the intrinsic defects recombine at Ce, Pr, or Tb via the conduction band.

Low-temperature VUV photoluminescence and thermoluminescence of UV excited afterglow phosphor Sr3AlxSi1-xO5:Ce(3+),Ln(3+) (Ln = Er, Nd, Sm, Dy and Tm).

Low-temperature (10 K) photoluminescence excitation and emission spectra of undoped Sr3SiO5 as well as Ce(3+) and Eu(3+) single doped Sr3SiO5 have been investigated. They show the host exciton band and the O(2-) to Eu(3+) charge transfer band at 5.98 eV (207 nm) and 3.

The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells.

Optical imaging for biological applications requires more sensitive tools. Near-infrared persistent luminescence nanoparticles enable highly sensitive in vivo optical detection and complete avoidance of tissue autofluorescence. However, the actual generation of persistent luminescence nanoparticles necessitates ex vivo activation before systemic administration, which prevents long-term imaging in living animals.

Electron transfer process between Ce3+ donor and Yb3+ acceptor levels in the bandgap of Y3Al5O12 (YAG).

Thermoluminescence (TL) properties of Ce(3+) and Yb(3+) co-doped in Y(3)Al(5)O(12) (YAG) were studied with the aim of determining the location of energy levels of Ce(3+) and Yb(2+) relative to the bottom of the conduction band (CB) and the top of the valence band (VB) of YAG. The TL glow peak at about 180 °C when heating rate β = 1°C s(-1) was assigned to electron release from Yb(2+), indicating that Yb(3+) acts as an electron trap. The trap depth, which is the depth of the ground-state level of Yb(2+) below the bottom of the CB, was derived from the temperatures of the maximum of the TL glow peak at different heating rates.

Some developments in neutron and charged particle dosimetry.

There is an increasing need for dosimetry of neutrons and charged particles. Increasing exposure levels are reported in the nuclear industry, deriving from more frequent in-service entries at commercial nuclear power plants, and from increased plant decommissioning and refurbishment activities. Another need stems from the compliance with requirements of the regulations and standards.

Broad-beam transmission data for new brachytherapy sources, Tm-170 and Yb-169.

The characteristics of the radionuclides (170)Tm and (169)Yb are highly interesting for their use as high dose-rate brachytherapy sources. The introduction of brachytherapy equipment containing these sources will lead to smaller required thicknesses of the materials used in radiation protection barriers compared with the use of conventional sources such as (192)Ir and (137)Cs. The purpose of this study is to determine the required thicknesses of protection material for the design of the protecting walls.

Passive detectors for neutron personal dosimetry: state of the art.

Passive, solid-state detectors still dominate the field of neutron personal dosimetry, mainly thanks to their low cost, high reliability and elevated throughput. However, the recent appearance in the market of several electronic personal dosemeters for neutrons presents a challenge to the exclusive use of passive systems for primary or official dosimetry. This scenario drives research and development activities on passive dosemeters towards systems offering greater accuracy of response and lower detection limits.

The radial depth-dose distribution of a 188W/188Re beta line source measured with novel, ultra-thin TLDs in a PMMA phantom: comparison with Monte Carlo simulations.

The radial depth-dose distribution of a prototype 188W/188Re beta particle line source of known activity has been measured in a PMMA phantom, using a novel, ultra-thin type of LiF:Mg,Cu,P thermoluminescent detector (TLD). The measured radial dose function of this intravascular brachytherapy source agrees well with MCNP4C Monte Carlo simulations, which indicate that 188Re accounts for > or = 99% of the dose between 1 mm and 5 mm radial distance from the source axis. The TLDs were calibrated using a 90Sr/90Y beta secondary standard.