Pham Dinh Khang B2107378 - Academia.edu (original) (raw)
Papers by Pham Dinh Khang B2107378
Cornell University - arXiv, Nov 12, 2013
The thermal neutron capture gamma radiations for 51 V(n,) 52 V reaction have been studied at Dala... more The thermal neutron capture gamma radiations for 51 V(n,) 52 V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52 V was measured as 7.31 MeV. Energy and intensity transition of cascades were consistent with prediction of single particle model. Further more, the spin and parity of levels were confined.
Cornell University - arXiv, Jul 1, 2013
Coincidence technique and the coincidence measurement systems have been developed and applied for... more Coincidence technique and the coincidence measurement systems have been developed and applied for over 40 years. Most of popular coincidence measurement systems were based on analog electronics techniques such as time to amplitude conversion (TAC) or logic selecting coincidence unit. The abovementioned systems are relatively cumbersome and complicated to use. With the strong growth of digital electronics techniques and computational science, the coincidence measurement systems will be constructed simpler but more efficient with the sake of application. This article presents the design principle and signal processing of a simple two-channel coincidence system by a new technique called Digital Signal Processing (DSP) using Field Programmable Gate Arrays (FPGA) devices at Nuclear Research Institute (NRI), Dalat.
IEEE Transactions on Instrumentation and Measurement
This article presents a composite (COM) method to obtain the high-resolution pulse shape discrimi... more This article presents a composite (COM) method to obtain the high-resolution pulse shape discrimination (PSD) for the neutron and gamma-ray pulses generated from scintillation detectors. The method, which is based on a selective combination of the digital charge integration (DCI) with the reference pulse method, aims to reduce the mixed radiation events in the low-energy range. An EJ-301 liquid scintillation detector together with a fast sampling analog-to-digital converter (ADC) is used to measure and digitize the pulses induced from the radioactive decays of 60Co and 252Cf, which are then analyzed by our COM method. The proposed method is evaluated using the figure of merit (FoM) and separation quality function F(u)F(u)F(u) , and the results are compared with three known methods, namely the DCI, standard event fit (SEF), and artificial neural network (ANN) methods. We show that the average values of FoM and F(u)F(u)F(u) obtained within the COM method are about ten times higher than those obtained within the DCI and SEF in the whole energy range from 50 to 1000 keV electron equivalent (keVee). In particular, by using the COM method, the percentage of gamma events being confused as neutrons ranges from 0.32% to 8.80% when the energy is reduced from 400 to 50 keVee. This finding, which is significantly lower than those obtained by using the DCI and SEF, indicates that the proposed COM method should be considered as a leading method for producing a neutron/gamma PSD counter system with high resolution.
IEEE Transactions on Nuclear Science
Cornell University - arXiv, Jul 11, 2013
By the financial support of Vietnam Atomic Energy Commission (VAEC) and kind cooperation of Frank... more By the financial support of Vietnam Atomic Energy Commission (VAEC) and kind cooperation of Frank Laboratory, in the year of 2005 a measure system based on summation of amplitude pulses (SACP) was established on the tangential channel of Dalat Research Reactor. After a serial of testing, the measure system was explored. In this, we would like to show the initial results were gotten with 36 Cl isotope.
Cornell University - arXiv, Jul 11, 2013
The summation amplitude of coincident pulses (SACP) method which is optimal solution to reduce co... more The summation amplitude of coincident pulses (SACP) method which is optimal solution to reduce compton scatter phenomenon and pairs phenomenon in the gamma spectra of nuclei decay gamma cascades was used. In the 1982, in comparision with original method [1], it was improved such as the interfacing techniques, and data analysis with aid of computer [2]. In order to get better, the fast/slow coincidence spectroscopy system was developed into a fast coincidence spectroscopy. It is advantageous and easy operation. The off-line measure results with radioactive source 60 Co and on-line measure results with 35 Cl target on the tangential channel of Dalat Research Reactor were showed the good abilities of this spectroscopy system.
IEEE Transactions on Nuclear Science, 2020
This work presents a high-resolution, high-confidence, and high-temperature-stabilization prototy... more This work presents a high-resolution, high-confidence, and high-temperature-stabilization prototype environmental radiation monitoring system (ERMS) with integrated digital filter, peak-finding algorithms, and real-time analyses. Through measuring 137Cs and 60Co radiation sources with the same NaI(Tl) detector, the features of the digital multichannel analyzer (DMCA) in our system, including throughput, energy resolution, and peak shape, were compared with those of a commercial instrument, namely the DSPEC jr 2.0 from ORTEC, USA. The results indicate that the full-width at half-maximum (FWHM) and peak heights obtained with our DMCA are better than those obtained with the DSPEC jr 2.0 up to 12%. The ERMS also integrates a solar power supply, multimodal data transmission, and a weather channel, thus facilitating its deployment in boundary areas or far islands for monitoring and forecasting radioactive propagation. Therefore, the proposed configuration system is highly promising in terms of performance and low cost of maintenance.
Copyright © 2014 Pham Dinh Khang et al. This is an open access article distributed under the Crea... more Copyright © 2014 Pham Dinh Khang et al. This is an open access article distributed under the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accordance of the Creative Commons Attribution License all Copyrights © 2014 are reserved for SCIRP and the owner of the intel-lectual property Pham Dinh Khang et al. All Copyright © 2014 are guarded by law and by SCIRP as a guardian. The thermal neutron capture gamma radiations for 51V(n, γ)52V reaction have been studied at Dalat Nuclear Re-search Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52V was measured as 7.31 MeV. Energy and the intensity transition of cascades were consistent with prediction of single particle model. Furthermore, the spin and the parity of levels were confined.
arXiv: Nuclear Experiment, 2019
The level scheme of the compound 153^{153}153Sm nucleus formed via the 152^{152}152Sm($n_{th}$,$\gamma$) ... more The level scheme of the compound 153^{153}153Sm nucleus formed via the 152^{152}152Sm($n_{th}$,$\gamma$) reaction is studied by using the gamma−gamma\gamma-\gammagamma−gamma coincidence spectrometer at Dalat Nuclear Research Institute, Vietnam. All the gamma cascades, which correspond to the decays from the compound state to 12 final levels of 0 ($\frac{3}{2}^+$), 7.535 ($\frac{5}{2}^+$), 35.844 ($\frac{3}{2}^-$), 90.875 ($\frac{5}{2}^-$), 126.412 ($\frac{1}{2}^-$), 127.298 ($\frac{3}{2}^-$), 182.902 ($\frac{5}{2}^-$), 321.113 ($\frac{3}{2}^+$), 404.129 ($\frac{1}{2}^-$), 405.470 ($\frac{3}{2}^-$), 414.924 ($\frac{1}{2}^+$), and 481.088 ($\frac{3}{2}^+$) keV, have been measured. A total number of 386 cascades corresponding to 576 gamma transitions has been detected. Among these cascades, 103 primary gamma transitions together with their corresponding intermediate levels and 299 secondary transitions have been determined. In addition, 29 primary gamma transitions, 42 intermediate levels, and 8 secondary transit...
The European Physical Journal A, 2021
Nuclear Physics A, 2021
Abstract This work presents the nuclear level scheme (NLS) of 164Dy nucleus obtained from the 163... more Abstract This work presents the nuclear level scheme (NLS) of 164Dy nucleus obtained from the 163Dy(n t h ,2γ) experiment. The latter has used a γ − γ coincidence spectrometer to measure the two-step gamma cascades corresponding to the decays from the compound state to 9 low-lying states of 164Dy, whose energies are 0.0, 73.393, 242.234, 761.815, 828.215, 915.991, 976.916, 1039.309, and 1122.774 keV. Based on the measured data, the 164Dy NLS, which consists of 64 primary gamma transitions and their corresponding intermediate levels, together with 132 secondary gamma transitions, has been constructed. Among these data, 20 primary gamma transitions, 51 intermediate levels, and 63 secondary gamma transitions are found to be the same as those currently exist in the Evaluated Nuclear Structure Data File (ENSDF) database. The remain data, which include 44 primary transitions, 13 intermediate levels, and 69 secondary transitions, are therefore, considered as an update for the NLS of 164Dy. In particular, the spin values of 57 observed intermediate levels have been tentatively assigned by means of transition rules. Furthermore, the influence of the present experimental data on the study of the nuclear level density and radiative strength function is also discussed.
![Research paper thumbnail of Erratum: Level scheme of Sm153 obtained from the Sm152(nth,γ) reaction using a γ−γ coincidence spectrometer [Phys. Rev. C 100 , 024324 (2019)]](https://attachments.academia-assets.com/95613877/thumbnails/1.jpg)
](Physical Review C, 2020
We found a mistake in the code which was used to calculate the back-shifted Fermi gas (BSFG) nucl... more We found a mistake in the code which was used to calculate the back-shifted Fermi gas (BSFG) nuclear level densities. This mistake is related to the BSFG results shown in Fig. 6 and Table II of the original article, which should be replaced with the corrected Fig. 6 and Table II, respectively. These corrected calculations point out that our claim in the original article that the BSFG model with the free parameters taken from Ref. [34] completely fails to describe both the total and the J-dependent experimental cumulative curves does not hold. Indeed, as can be seen in the corrected Fig. 6, the BSFG with the free parameters taken from Ref. [34] describes fairly well the J-dependent experimental cumulative curve and the low-energy part (i.e., less than 0.5 MeV) of the total cumulative one. Fortunately, these changes do not affect our conclusion in the original article that the recent exact pairing plus independentparticle model at finite temperature is found to be the best-fitted one.
Nuclear Engineering and Technology, 2018
This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 p... more This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 photomultiplier and a homemade preamplifier. The detector qualities which include the energy linearity, efficiency response and neutron/gamma discrimination are guaranteed for neutron detection in the energy range from 0 to 3000 keVee. Regarding the neutron/gamma discrimination capability, four pulse shape discrimination (PSD) methods which are the threshold crossing time (TCT), pulse gradient analysis (PGA), charge comparison (CC) and correlation pattern recognition (CPR), were evaluated and discussed; among of these, the CPR method provides the best neutron/gamma discrimination.
IOSR Journal of Engineering, 2013
In this paper, the results showed experimental transition strengths of 52 V by two-step gamma cas... more In this paper, the results showed experimental transition strengths of 52 V by two-step gamma cascades, lifetime levels, width levels and branch ratio. 51 V nucleus was activated by thermal neutron at the 3 rd horizontal channel of Dalat nuclear reactor, and the 51 V(n th , 2 gamma) 52 V reaction was applied in this research. The two-step gamma cascades were collected by event-event gamma coincidence system. The Summation of Amplitude Coincidence Pulses method (SACP) was treated with the experimental data. The results were not affected by background based on SACP method. This method got intensities, energies of two-step cascades directly. The experimental gamma transition strengths were applied to the single particle model. In comparison with the electromagnetic transition probabilities, and rule of multi orders, the spin and parity of intermediate levels were calculated and refreshed.
Asian Journal of Chemistry, 2016
The high compton background and peak overlap restrict the applicability of instrumental neutron a... more The high compton background and peak overlap restrict the applicability of instrumental neutron activation analysis (INAA). The coincidence technique can greatly reduce these problems. Some previous results have proved the ability of event-event coincidence method for determination of elements with overlap peaks in complex matrix sample. In this work, we analyzed arsenic in geological sample to evaluate advantages of the coincidence technique in instrumental neutron activation analysis. An innovation in data analysis process, which helps to reduce the measurement time and to improve the detection limit is also presented.
This report is presented the level densities and gamma strength function which is extracted from ... more This report is presented the level densities and gamma strength function which is extracted from primary gamma transitions of (n,2) measurement on the Dalat Nuclear Research Reactor (DNRR). The comparisons with others results and model calculations, there are outside the scope of uncertainty. These research results are showed that having of complement research for deformed nucleus in order to evaluate nuclear structure models.
Cornell University - arXiv, Nov 12, 2013
The thermal neutron capture gamma radiations for 51 V(n,) 52 V reaction have been studied at Dala... more The thermal neutron capture gamma radiations for 51 V(n,) 52 V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52 V was measured as 7.31 MeV. Energy and intensity transition of cascades were consistent with prediction of single particle model. Further more, the spin and parity of levels were confined.
Cornell University - arXiv, Jul 1, 2013
Coincidence technique and the coincidence measurement systems have been developed and applied for... more Coincidence technique and the coincidence measurement systems have been developed and applied for over 40 years. Most of popular coincidence measurement systems were based on analog electronics techniques such as time to amplitude conversion (TAC) or logic selecting coincidence unit. The abovementioned systems are relatively cumbersome and complicated to use. With the strong growth of digital electronics techniques and computational science, the coincidence measurement systems will be constructed simpler but more efficient with the sake of application. This article presents the design principle and signal processing of a simple two-channel coincidence system by a new technique called Digital Signal Processing (DSP) using Field Programmable Gate Arrays (FPGA) devices at Nuclear Research Institute (NRI), Dalat.
IEEE Transactions on Instrumentation and Measurement
This article presents a composite (COM) method to obtain the high-resolution pulse shape discrimi... more This article presents a composite (COM) method to obtain the high-resolution pulse shape discrimination (PSD) for the neutron and gamma-ray pulses generated from scintillation detectors. The method, which is based on a selective combination of the digital charge integration (DCI) with the reference pulse method, aims to reduce the mixed radiation events in the low-energy range. An EJ-301 liquid scintillation detector together with a fast sampling analog-to-digital converter (ADC) is used to measure and digitize the pulses induced from the radioactive decays of 60Co and 252Cf, which are then analyzed by our COM method. The proposed method is evaluated using the figure of merit (FoM) and separation quality function F(u)F(u)F(u) , and the results are compared with three known methods, namely the DCI, standard event fit (SEF), and artificial neural network (ANN) methods. We show that the average values of FoM and F(u)F(u)F(u) obtained within the COM method are about ten times higher than those obtained within the DCI and SEF in the whole energy range from 50 to 1000 keV electron equivalent (keVee). In particular, by using the COM method, the percentage of gamma events being confused as neutrons ranges from 0.32% to 8.80% when the energy is reduced from 400 to 50 keVee. This finding, which is significantly lower than those obtained by using the DCI and SEF, indicates that the proposed COM method should be considered as a leading method for producing a neutron/gamma PSD counter system with high resolution.
IEEE Transactions on Nuclear Science
Cornell University - arXiv, Jul 11, 2013
By the financial support of Vietnam Atomic Energy Commission (VAEC) and kind cooperation of Frank... more By the financial support of Vietnam Atomic Energy Commission (VAEC) and kind cooperation of Frank Laboratory, in the year of 2005 a measure system based on summation of amplitude pulses (SACP) was established on the tangential channel of Dalat Research Reactor. After a serial of testing, the measure system was explored. In this, we would like to show the initial results were gotten with 36 Cl isotope.
Cornell University - arXiv, Jul 11, 2013
The summation amplitude of coincident pulses (SACP) method which is optimal solution to reduce co... more The summation amplitude of coincident pulses (SACP) method which is optimal solution to reduce compton scatter phenomenon and pairs phenomenon in the gamma spectra of nuclei decay gamma cascades was used. In the 1982, in comparision with original method [1], it was improved such as the interfacing techniques, and data analysis with aid of computer [2]. In order to get better, the fast/slow coincidence spectroscopy system was developed into a fast coincidence spectroscopy. It is advantageous and easy operation. The off-line measure results with radioactive source 60 Co and on-line measure results with 35 Cl target on the tangential channel of Dalat Research Reactor were showed the good abilities of this spectroscopy system.
IEEE Transactions on Nuclear Science, 2020
This work presents a high-resolution, high-confidence, and high-temperature-stabilization prototy... more This work presents a high-resolution, high-confidence, and high-temperature-stabilization prototype environmental radiation monitoring system (ERMS) with integrated digital filter, peak-finding algorithms, and real-time analyses. Through measuring 137Cs and 60Co radiation sources with the same NaI(Tl) detector, the features of the digital multichannel analyzer (DMCA) in our system, including throughput, energy resolution, and peak shape, were compared with those of a commercial instrument, namely the DSPEC jr 2.0 from ORTEC, USA. The results indicate that the full-width at half-maximum (FWHM) and peak heights obtained with our DMCA are better than those obtained with the DSPEC jr 2.0 up to 12%. The ERMS also integrates a solar power supply, multimodal data transmission, and a weather channel, thus facilitating its deployment in boundary areas or far islands for monitoring and forecasting radioactive propagation. Therefore, the proposed configuration system is highly promising in terms of performance and low cost of maintenance.
Copyright © 2014 Pham Dinh Khang et al. This is an open access article distributed under the Crea... more Copyright © 2014 Pham Dinh Khang et al. This is an open access article distributed under the Creative Commons Attribution Li-cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accordance of the Creative Commons Attribution License all Copyrights © 2014 are reserved for SCIRP and the owner of the intel-lectual property Pham Dinh Khang et al. All Copyright © 2014 are guarded by law and by SCIRP as a guardian. The thermal neutron capture gamma radiations for 51V(n, γ)52V reaction have been studied at Dalat Nuclear Re-search Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52V was measured as 7.31 MeV. Energy and the intensity transition of cascades were consistent with prediction of single particle model. Furthermore, the spin and the parity of levels were confined.
arXiv: Nuclear Experiment, 2019
The level scheme of the compound 153^{153}153Sm nucleus formed via the 152^{152}152Sm($n_{th}$,$\gamma$) ... more The level scheme of the compound 153^{153}153Sm nucleus formed via the 152^{152}152Sm($n_{th}$,$\gamma$) reaction is studied by using the gamma−gamma\gamma-\gammagamma−gamma coincidence spectrometer at Dalat Nuclear Research Institute, Vietnam. All the gamma cascades, which correspond to the decays from the compound state to 12 final levels of 0 ($\frac{3}{2}^+$), 7.535 ($\frac{5}{2}^+$), 35.844 ($\frac{3}{2}^-$), 90.875 ($\frac{5}{2}^-$), 126.412 ($\frac{1}{2}^-$), 127.298 ($\frac{3}{2}^-$), 182.902 ($\frac{5}{2}^-$), 321.113 ($\frac{3}{2}^+$), 404.129 ($\frac{1}{2}^-$), 405.470 ($\frac{3}{2}^-$), 414.924 ($\frac{1}{2}^+$), and 481.088 ($\frac{3}{2}^+$) keV, have been measured. A total number of 386 cascades corresponding to 576 gamma transitions has been detected. Among these cascades, 103 primary gamma transitions together with their corresponding intermediate levels and 299 secondary transitions have been determined. In addition, 29 primary gamma transitions, 42 intermediate levels, and 8 secondary transit...
The European Physical Journal A, 2021
Nuclear Physics A, 2021
Abstract This work presents the nuclear level scheme (NLS) of 164Dy nucleus obtained from the 163... more Abstract This work presents the nuclear level scheme (NLS) of 164Dy nucleus obtained from the 163Dy(n t h ,2γ) experiment. The latter has used a γ − γ coincidence spectrometer to measure the two-step gamma cascades corresponding to the decays from the compound state to 9 low-lying states of 164Dy, whose energies are 0.0, 73.393, 242.234, 761.815, 828.215, 915.991, 976.916, 1039.309, and 1122.774 keV. Based on the measured data, the 164Dy NLS, which consists of 64 primary gamma transitions and their corresponding intermediate levels, together with 132 secondary gamma transitions, has been constructed. Among these data, 20 primary gamma transitions, 51 intermediate levels, and 63 secondary gamma transitions are found to be the same as those currently exist in the Evaluated Nuclear Structure Data File (ENSDF) database. The remain data, which include 44 primary transitions, 13 intermediate levels, and 69 secondary transitions, are therefore, considered as an update for the NLS of 164Dy. In particular, the spin values of 57 observed intermediate levels have been tentatively assigned by means of transition rules. Furthermore, the influence of the present experimental data on the study of the nuclear level density and radiative strength function is also discussed.
Physical Review C, 2020
We found a mistake in the code which was used to calculate the back-shifted Fermi gas (BSFG) nucl... more We found a mistake in the code which was used to calculate the back-shifted Fermi gas (BSFG) nuclear level densities. This mistake is related to the BSFG results shown in Fig. 6 and Table II of the original article, which should be replaced with the corrected Fig. 6 and Table II, respectively. These corrected calculations point out that our claim in the original article that the BSFG model with the free parameters taken from Ref. [34] completely fails to describe both the total and the J-dependent experimental cumulative curves does not hold. Indeed, as can be seen in the corrected Fig. 6, the BSFG with the free parameters taken from Ref. [34] describes fairly well the J-dependent experimental cumulative curve and the low-energy part (i.e., less than 0.5 MeV) of the total cumulative one. Fortunately, these changes do not affect our conclusion in the original article that the recent exact pairing plus independentparticle model at finite temperature is found to be the best-fitted one.
Nuclear Engineering and Technology, 2018
This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 p... more This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 photomultiplier and a homemade preamplifier. The detector qualities which include the energy linearity, efficiency response and neutron/gamma discrimination are guaranteed for neutron detection in the energy range from 0 to 3000 keVee. Regarding the neutron/gamma discrimination capability, four pulse shape discrimination (PSD) methods which are the threshold crossing time (TCT), pulse gradient analysis (PGA), charge comparison (CC) and correlation pattern recognition (CPR), were evaluated and discussed; among of these, the CPR method provides the best neutron/gamma discrimination.
IOSR Journal of Engineering, 2013
In this paper, the results showed experimental transition strengths of 52 V by two-step gamma cas... more In this paper, the results showed experimental transition strengths of 52 V by two-step gamma cascades, lifetime levels, width levels and branch ratio. 51 V nucleus was activated by thermal neutron at the 3 rd horizontal channel of Dalat nuclear reactor, and the 51 V(n th , 2 gamma) 52 V reaction was applied in this research. The two-step gamma cascades were collected by event-event gamma coincidence system. The Summation of Amplitude Coincidence Pulses method (SACP) was treated with the experimental data. The results were not affected by background based on SACP method. This method got intensities, energies of two-step cascades directly. The experimental gamma transition strengths were applied to the single particle model. In comparison with the electromagnetic transition probabilities, and rule of multi orders, the spin and parity of intermediate levels were calculated and refreshed.
Asian Journal of Chemistry, 2016
The high compton background and peak overlap restrict the applicability of instrumental neutron a... more The high compton background and peak overlap restrict the applicability of instrumental neutron activation analysis (INAA). The coincidence technique can greatly reduce these problems. Some previous results have proved the ability of event-event coincidence method for determination of elements with overlap peaks in complex matrix sample. In this work, we analyzed arsenic in geological sample to evaluate advantages of the coincidence technique in instrumental neutron activation analysis. An innovation in data analysis process, which helps to reduce the measurement time and to improve the detection limit is also presented.
This report is presented the level densities and gamma strength function which is extracted from ... more This report is presented the level densities and gamma strength function which is extracted from primary gamma transitions of (n,2) measurement on the Dalat Nuclear Research Reactor (DNRR). The comparisons with others results and model calculations, there are outside the scope of uncertainty. These research results are showed that having of complement research for deformed nucleus in order to evaluate nuclear structure models.