@article{chang_meric_sudac_nad_obhodas_hou_zhang_gardner_2019, title={Implementation of the Monte Carlo Library Least-Squares (MCLLS) approach for quantification of the chlorine impurity in an on-line crude oil monitoring system}, volume={155}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2018.05.012}, abstractNote={Abstract Prompt gamma-ray neutron activation analysis (PGNAA) has been widely used for elemental analysis of bulk samples as it provides an on-line, rapid and non-destructive means of performing such analysis. The Monte Carlo Library Least-Squares (MCLLS) approach is one of the methods for quantitative analysis providing elemental weight fractions via an assumption that the total prompt gamma-ray spectrum is a linear combination of the contributions from the individual prompt gamma-ray spectra of the sample constituents. For the generation of prompt gamma-ray libraries of each constituent, a specific purpose Monte Carlo code system called Center for Engineering Applications of Radioisotopes Coincidence Prompt Gamma-Ray (CEARCPG) is utilized. In this work, the focus was on detecting and measuring chlorine impurity in crude oil samples, i.e. trace amounts of chlorine. A preliminary study investigating the feasibility of PGNAA method in conjunction with the MCLLS approach for measuring trace amounts of chlorine in oil samples was performed. For this purpose, an extended version of the MCLLS approach, the so-called MCLLSX approach, was proposed and applied for the quantitative analysis. The results presented in this paper prove the feasibility of the proposed approach.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Chang, Hao Ping and Meric, Ilker and Sudac, Davorin and Nad, Karlo and Obhodas, Jasmina and Hou, Guojing and Zhang, Yan and Gardner, Robin P.}, year={2019}, month={Feb}, pages={197–201} }
 @article{zhang_jia_gardner_shan_zhang_hou_chang_2017, title={A distance correction method for improving the accuracy of particle coal online X-ray fluorescence analysis - Part 2: Method and experimental investigation}, volume={141}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2017.07.004}, abstractNote={Abstract The distance from X-Ray Fluorescence (XRF) spectrometer to sample surface always changes with the different coal's particle sizes, resulting in the inaccuracy of online XRF measurement. To improve the accuracy of particle coal online XRF analysis, a distance correction method was established elaborated by iteration, which was based on the relationship between the XRF intensity and the distance. In order to verify the effectiveness of this method, five different particle size coal samples with same components have been measured by the online XRF analyzer directly above the conveyor belt, in the meanwhile, the distances between XRF spectrometer and samples’ surface were obtained by a laser rangefinder. The results showed that the average distances are decreased with decreasing the particle size. By comparing the results of before and after applying the distance correction method, we demonstrated that the measurement accuracy of online XRF analysis for particle coal can be significantly increased. The distance correction method can be used for the development of online XRF analysis techniques applicable for real-time industrial processes.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Zhang, Yan and Jia, Wen Bao and Gardner, Robin and Shan, Qing and Zhang, Xin Lei and Hou, Guojing and Chang, Hao Ping}, year={2017}, month={Dec}, pages={235–238} }
 @article{liu_zhang_gardner_hou_zhang_zhang_li_li_hu_2016, title={A method to improve the sensitivity of neutron porosity measurement based on D-T source}, volume={33}, ISSN={["2212-3865"]}, DOI={10.1016/j.jngse.2016.06.028}, abstractNote={Abstract Compensated porosity logging tool utilizing deuterium-tritium (D-T) source shows a lower sensitivity to the variation of formation porosity compared with that adopting Am-Be source. In order to improve the sensitivity, the factors of an infinite homogeneous formation influencing slowing-down length and the near to far counts ratio are analyzed. Then Monte Carlo simulation method is used to build well logging models to study the responses of a neutron porosity logging tool to hydrogen index and formation density. It shows that in addition to hydrogen index, the variation of the density also has a great impact on slowing-down length and the ratio which reduces the response sensitivity to porosity. A new model depicts the relationship between the count ratio and porosity is proposed. When the model is used to process the measured ratio, the ratio shows improved dynamic range and sensitivity to porosity compared with the values without processing.}, journal={JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING}, author={Liu, Juntao and Zhang, Feng and Gardner, Robin P. and Hou, Guojing and Zhang, Quanying and Zhang, Yan and Li, Xianghui and Li, Hu and Hu, Cong}, year={2016}, month={Jul}, pages={879–884} }
 @article{liu_zhang_gardner_hou_zhang_li_2015, title={A method to evaluate hydraulic fracture using proppant detection}, volume={105}, ISSN={["0969-8043"]}, DOI={10.1016/j.apradiso.2015.08.003}, abstractNote={Accurate determination of the proppant placement and propped fracture height are important for evaluating and optimizing stimulation strategies. A technology using non-radioactive proppant and a pulsed neutron gamma energy spectra logging tool to determine the placement and height of propped fractures is proposed. Gd2O3 was incorporated into ceramic proppant and a Monte Carlo method was utilized to build the logging tools and formation models. Characteristic responses of the recorded information of different logging tools to fracture widths, proppant concentrations and influencing factors were studied. The results show that Gd capture gamma rays can be used to evaluate propped fractures and it has higher sensitivity to the change of fracture width and traceable proppant content compared with the exiting non-radioactive proppant evaluation techniques and only an after-fracture measurement is needed for the new method; The changes in gas saturation and borehole size have a great impact on determining propped fractures when compensated neutron and pulsed neutron capture tool are used. A field example is presented to validate the application of the new technique.}, journal={APPLIED RADIATION AND ISOTOPES}, author={Liu, Juntao and Zhang, Feng and Gardner, Robin P. and Hou, Guojing and Zhang, Quanying and Li, Hu}, year={2015}, month={Nov}, pages={139–143} }
 @article{hou_gardner_2015, title={A new G-M counter hybrid dead-time correction model}, volume={116}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2015.05.014}, abstractNote={Abstract A new G–M counter dead-time model based on the hybrid model is proposed and studied. The new model contains the idealized paralyzable and non-paralyzable dead-time models, but also allows the non-paralyzable dead-time to vary with the true counting rate. To validate this model, the decaying source experiment with a very pure 56 Mn source was used. The calculated true counting rates obtained by fitting the experimental data to the model were compared to the data obtained by table lookup. In general, the fitting was in good agreement (within 4.8% up to 5.35 × 10 6 counts / minute ) for a G–M counter with a paralyzable dead-time component of 85.9 μs and a non-paralyzable dead-time component ranging from 438 μs to 24.3 ms.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Hou, Guojing and Gardner, Robin P.}, year={2015}, month={Nov}, pages={125–129} }