@article{guo_lee_gardner_2004, title={The Monte Carlo approach MCPUT for correcting pile-up distorted pulse-height spectra}, volume={531}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2004.05.089}, abstractNote={Pulse pile-up distortion is a common problem for radiation spectroscopy measurements involving high counting rates. The Monte Carlo pile-up to true approach (MCPUT) is proposed and benchmarked in this article for correcting pile-up distorted pulse-height spectra to true spectra. In previous work, a Monte Carlo approach was used for predicting the pile-up distorted pulse-height spectra for high counting-rate measurements (“the forward calculation”). The present work improves the previous simulation by employing a better ADC dead-time model. Based on this improved “forward calculation”, the MCPUT approach introduces an iterative procedure for correcting pile-up distortions. Experiments with an Fe-55 source and a Si(Li) detector are used for benchmarking purposes. The MCPUT corrected spectrum for the high counting-rate measurement shows excellent agreement with the measured true spectrum at low counting rate with reduced chi-square as the quantitative measure. The approach is also efficient, as accurate calculations are possible in a few minutes.}, number={3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Guo, WJ and Lee, SH and Gardner, RP}, year={2004}, month={Oct}, pages={520–529} }
 @article{lee_gardner_todd_2001, title={Preliminary studies on combining the K and L XRF methods for in vivo bone lead measurement}, volume={54}, DOI={10.1016/s0969-8043(00)00350-x}, abstractNote={Lead is a toxic material that invokes irreversible neurological problems. Once ingested, lead accumulates in the bones. To study detailed lead poisoning effects it is essential to have an in vivo bone lead measurement tool with a small minimum detectable concentration (MDC). Both K- and L-based XRF methods for the tibia bone have been suggested and developed in the past and are presently in use. In this work a combined K and L XRF method for the tibia bone is proposed. The proposed system consists of a 109Cd point source and Ge and Si(Li) detectors for optimum detection of the K and L X-rays, respectively. Experimental and Monte Carlo simulated results are given here for a prototype combined K and L XRF system. This system promises to yield a better MDC and the possibility of obtaining information on the near-surface bone lead content as well as the average lead content throughout the bone.}, number={6}, journal={Applied Radiation and Isotopes}, author={Lee, S. H. and Gardner, R. P. and Todd, A. C.}, year={2001}, pages={893–904} }
 @article{lee_gardner_2000, title={A new G-M counter dead time model}, volume={53}, ISSN={["0969-8043"]}, DOI={10.1016/S0969-8043(00)00261-X}, abstractNote={A hybrid G–M counter dead time model was derived by combining the idealized paralyzable and non-paralyzable models. The new model involves two parameters, which are the paralyzable and non-paralyzable dead times. The dead times used in the model are very closely related to the physical dead time of the G–M tube and its resolving time. To check the validity of the model, the decaying source method with 56Mn was used. The corrected counting rates by the new G–M dead time model were compared with the observed counting rates obtained from the measurement and gave very good agreement within 5% up to 7 × 104 counts/s for a G–M tube with a dead time of about 300 μs.}, number={4-5}, journal={APPLIED RADIATION AND ISOTOPES}, author={Lee, SH and Gardner, RP}, year={2000}, pages={731–737} }
 @article{ao_lee_gardner_1997, title={Development of the specific purpose Monte Carlo code CEARXRF for the design and use of in vivo X-ray fluorescence analysis systems for lead in bone}, volume={48}, ISSN={["0969-8043"]}, DOI={10.1016/S0969-8043(97)00136-X}, abstractNote={X-ray fluorescence (XRF) systems have been increasingly used for in vivo toxic trace-element analysis in the human body, such as lead in the tibia. Monte Carlo simulation can provide an efficient and flexible method for designing and using in vivo XRF systems. The Monte Carlo code CEARXRF has been developed specifically to simulate the complete pulse height spectrum of energy-dispersive XRF systems. This code is capable of tracking photons in a general geometry and modelling all of the physics of photon interactions in the energy range 1-150 keV for elements Z = 1-94, including primary and higher degree excitations of K and L XRF, the Doppler broadening of Compton-scattered photon energies, and the polarization effects in low-energy photon scatterings. The scattering background for minimum detectable concentration (MDC) analysis may be simulated more accurately by taking into account Doppler broadening in the distribution of the Compton-scattered photon energy due to electron-binding effects. The use of polarized excitation photons has been shown to be important in producing a low scattering background and good measurement sensitivity. The code has two very unique and important features: (1) complete composition and density correlated sampling that is extremely useful for studying measurement sensitivity to small changes in sample composition and density; and (2) Monte Carlo library spectra calculation for the determination of elemental amounts by the Monte Carlo-Library Least-Squares (MCLLS) method. The capability of CEARXRF to aid the design and optimization of in vivo XRF analysis has been verified by modelling hypothesized lead K and L XRF measurement systems.}, number={10-12}, journal={APPLIED RADIATION AND ISOTOPES}, author={Ao, Q and Lee, SH and Gardner, RP}, year={1997}, pages={1403–1412} }