Adrie Bos | Delft University of Technology (original) (raw)
Papers by Adrie Bos
Radiation Measurements, 2023
Radiation Protection Dosimetry, 2006
There is an increasing need for dosimetry of neutrons and charged particles. Increasing exposure ... more 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. The European Council directive 96/29 requires dosimetric precautions if the effective dose exceeds 1 mSv a(-1). On average, aircrew members exceed this value. Further, there is a trend of increasing use of charged particles in radiotherapy. The present situation is that we have reasonably good photon dosemeters, but neutron and charged particle dosemeters are still in need of improvements. This work highlights some of the developments in this field. It is mainly concentrated on some developments in passive dosimetry, in particular thermally and optically stimulated luminescent detectors, indicating the direction of ongoing research. It shows that passive dosemeters are still a very active field. Active dosemeters will not be discussed with the exception of new developments in microdosimetric measurements [new types of tissue equivalent proportional counters (TEPCs)]. The TEPC is unique in its ability to provide a simultaneous determination of neutron / charged particle / gamma ray doses, or dose equivalents using a single detector.
Radiation Measurements, 2012
Radiation Measurements, 2010
Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow ... more Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow curves of a powder sample of YPO 4 :Ce 3þ ,Sm 3þ were measured to investigate the nature of the trapping centre and to locate its energy level relative to the valence and conduction bands of the YPO 4 host. The high-temperature glow peak could unequivocally be assigned to Sm 2þ (thus Sm 3þ acts as an electron trap). The trap depth of this centre, as derived from the OSL excitation spectra, is in good agreement with the Dorenbos model prediction. The OSL excitation spectra also reveal excited states of Sm 2þ well below the conduction band. These excited states produce a broadening of the high-temperature TL glow peak and also cause the activation energy determined by the Hoogenstraten method to underestimate the trap depth.
Radiation Measurements, 2009
A mathematical transformation based on differentiation is introduced that converts a Continuous W... more A mathematical transformation based on differentiation is introduced that converts a Continuous Wave Optically Stimulated Luminescence (CW-OSL) decay curve composed of a number of exponentials into a spectrum like curve with different peaks. Peak areas of the transformed curve are equal to the time integrated OSL of the exponentials. It is shown that the peaks of the transformed curve are more separated then the original decay curve components. The transformation is applied to computer generated OSL curves and to measured CW-OSL decay curves of three different quartz samples. Advantages and limitations of this differentiation analysis method are discussed.
Materials (Basel, Switzerland), Jan 26, 2017
Thermally stimulated luminescence (TSL) is known as a technique used in radiation dosimetry and d... more 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. First, some basic characteristics and a theoretical background of the phenomenon are given. Next, methods and difficulties in extracting trapping parameters are addressed. Then, the instrumentation needed to measure the luminescence, both as a function of temperature and wavelength, is described. Finally, a series of very diverse examples is given to illustrate how TSL has been used in the determination of energy levels of defects, in the research of persistent luminescence phosphors, and in phenomena like band gap engineering, tunnelling, photosynthesis, and thermal quenching. It is concluded that in the field of lum...
The journal of physical chemistry. C, Nanomaterials and interfaces, Jan 27, 2017
Two different charge carrier trapping processes have been investigated in RE2O2S:Ln(3+) (RE = La,... more Two different charge carrier trapping processes have been investigated in RE2O2S:Ln(3+) (RE = La, Gd, Y, and Lu; Ln = Ce, Pr, and Tb) and RE2O2S:M (M = Ti(4+) and Eu(3+)). 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(4+), Pr(4+), or Tb(4+) via the conduction band. On the other hand, Ti(4+) and Eu(3+) act as recombination centers and electron trapping centers while host intrinsic defects act as hole trapping centers. For these codopants we find evidence that recombination is by means of hole release instead of electron release. The released holes recombine with the trapped electrons on Ti(3+) or Eu(2+) and yield broad Ti(4+) yellow-red charge transfer (CT) emission or characteristic Eu(3+) 4f-4f emission. We will conclude that the afterglow in Y2O2S:Ti(4+), Eu(3+) is due to hole release instead of more common ele...
Review of Scientific Instruments, 1993
ABSTRACT
![Research paper thumbnail of Lanthanide 4f-level location in lanthanide doped and cerium-lanthanide codoped NaLaF[sub 4] by photo- and thermoluminescence](https://attachments.academia-assets.com/68104695/thumbnails/1.jpg)
](Journal of Applied Physics, 2008
Tm͒ are presented and used together with the empirical Dorenbos model in order to establish the 4... more Tm͒ are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri-and divalent lanthanide ions doped in NaLaF 4. The information will be presented in the form of an energy level diagram. It is shown that in addition to this diagram only two assumptions, viz., the presence of two host related electron traps and the presence of V k-centers, are necessary for explaining the lanthanide-specific TL glow curves of both Ln mono-and Ce-Ln codoped NaLaF 4 .
The effects of the cooling rate alpha and heating rate beta on trapping parameters and thermolumi... more The effects of the cooling rate alpha and heating rate beta on trapping parameters and thermoluminescent (TL) glow peak intensities in LiF:Mg, Ti(TLD-100) crystals have been studied by glow curve fitting from room temperature to 500 K. It is found that under the investigated circumstances (1 K min-1< alpha < 5000 K min-1, 0.12 K s-1 < beta FOM>0.2%). Glow
We investigate both theoretically and experimentally the effect of stimulation mode on the separa... more We investigate both theoretically and experimentally the effect of stimulation mode on the separation of quartz optically stimulated luminescence (OSL) components. We find that, when assuming first-order kinetics with the detrapping probability proportional to stimulation intensity, the OSL signal is a function of the cumulative stimulation energy and not affected by the stimulation mode. This is confirmed by close correspondence between continuous wave (CW), linearly modulated (LM) and hyperbolically modulated (HM) OSL data for some of the samples studied. For other samples the data obtained using LM stimulation differ from that obtained using the other stimulation modes. This may be due to a contribution to the OSL signal from feldspars, or it may indicate that the behaviour of these samples is not adequately described by first-order kinetics. We suggest that CW stimulation is the method of choice for dating purposes as it allows the fastest readout with the greatest signal-to-noise ratio, and because it has a constant background. HM stimulation provides a good alternative when higher resolution is needed for the initial part of the shine-down curve.
Quaternary Geochronology, Dec 31, 2007
Infrared-stimulated luminescence (IRSL) dating of feldspars has the potential to date deposits be... more Infrared-stimulated luminescence (IRSL) dating of feldspars has the potential to date deposits beyond the age range of quartz optical (OSL) dating. Successful application of feldspar IRSL dating is, however, often precluded due to anomalous-fading, the tunnelling of electrons from one defect site to another. In this paper we test procedures proposed for anomalous-fading correction by comparing feldspar IRSL and quartz OSL dating results on a suite of samples from continental deposits from the southeastern Netherlands. We find ...
The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stim... more The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stimulation power (CW-OSL) is a featureless decay curve where underlying components cannot be identified easily. Visual interpretation of quartz OSL signals is easier if signals are shown in spectrum-like form. This can be achieved either through ramped stimulation, or by transforming a measured CW-OSL curve into a pseudo OSL curve. We show that both give similar results, but that transformation should be preferred as CW-OSL provides best signal-to-noise ratios. We present different transformation methods to obtain pseudo OSL curves and discuss the advantages and disadvantages of each method. In addition, we show that different pseudo OSL transformations can be used to emphasize specific aspects of the OSL signal. We conclude that transformation of CW-OSL to pseudo hyperbolically modulated OSL provides the most useful visualization of the quartz fast OSL component. Pseudo parabolic modulated OSL is the transformation of choice for showing the slow component(s). The pseudo OSL curves can be used for rapid visual inspection of the relative contribution of the OSL components prior to further analysis.
Thermoluminescence (TL) emission spectra and TL glow curves of powder samples of YPO 4 :Ce 3+ , L... more Thermoluminescence (TL) emission spectra and TL glow curves of powder samples of YPO 4 :Ce 3+ , Ln 3+ (Ln 3+ = Nd 3+ , Sm 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+) were measured in order to investigate the nature of the trapping centres and to locate the lanthanide energy levels relative to the valence and conduction bands of the YPO 4 host. Trap depths were determined by three different TL techniques (simple formula, various heating rate method and glow curve fitting) and compared with an earlier developed predictive energy level scheme. The nature of the trapping centres agrees with that predicted by the energy level scheme. Further, the trend of trap depths of the divalent lanthanides (Ln 2+ = Nd 2+ , Sm 2+ , Dy 2+ , Ho 2+ , Er 2+ , Tm 2+) agrees very well with the trend of levels determined by three different thermoluminescent techniques. It is concluded that the energy level scheme can help in the development of new TL materials suitable in dosimetry.
Nucl Instrum Meth Phys Res a, 2003
We have studied the operation of two different Gas Electron Multiplier (GEM) structures in both m... more We have studied the operation of two different Gas Electron Multiplier (GEM) structures in both methane and propane based Tissue-Equivalent (TE) gases at different pressures varying from 0.1 to 1 atm. This work was motivated to explore the possibility of using a GEM for a new type of Tissue Equivalent Proportional Counter. In methane based TE gas, a maximum safe GEM gain of 1.5×10 3 has been reached while in propane based TE gas this is 6×10 3. These maxima have been reached at different gas pressures depending on GEM structure and TE gas. Furthermore, we observed a decrease of the GEM gain in time before it becomes stable. Charge up/polarisation effects can explain this.
Radiation Measurements, 2008
Physical Review B Condensed Matter and Materials Physics, 2009
The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stim... more The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stimulation power (CW-OSL) is a featureless decay curve where underlying components cannot be identified easily. Visual interpretation of quartz OSL signals is easier if signals are shown in spectrum-like form. This can be achieved either through ramped stimulation, or by transforming a measured CW-OSL curve into a pseudo OSL curve. We show that both give similar results, but that transformation should be preferred as CW-OSL provides best signal-to-noise ratios. We present different transformation methods to obtain pseudo OSL curves and discuss the advantages and disadvantages of each method. In addition, we show that different pseudo OSL transformations can be used to emphasize specific aspects of the OSL signal. We conclude that transformation of CW-OSL to pseudo hyperbolically modulated OSL provides the most useful visualization of the quartz fast OSL component. Pseudo parabolic modulated OSL is the transformation of choice for showing the slow component(s). The pseudo OSL curves can be used for rapid visual inspection of the relative contribution of the OSL components prior to further analysis.
Radiat Meas, 2008
The consequences of irradiating ∅1in×1inLaBr3:5%Ce crystals with 0.1–100kGy gamma radiation have ... more The consequences of irradiating ∅1in×1inLaBr3:5%Ce crystals with 0.1–100kGy gamma radiation have been investigated. The material displays lower photoelectron yield and poorer energy resolution after exposure to a 60Co source. The magnitude of the damage is larger in a packed scintillator. In addition to a prompt effect following gamma irradiation, consisting of a deterioration in both photoelectron yield and energy resolution,
Radiation Measurements, 2023
Radiation Protection Dosimetry, 2006
There is an increasing need for dosimetry of neutrons and charged particles. Increasing exposure ... more 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. The European Council directive 96/29 requires dosimetric precautions if the effective dose exceeds 1 mSv a(-1). On average, aircrew members exceed this value. Further, there is a trend of increasing use of charged particles in radiotherapy. The present situation is that we have reasonably good photon dosemeters, but neutron and charged particle dosemeters are still in need of improvements. This work highlights some of the developments in this field. It is mainly concentrated on some developments in passive dosimetry, in particular thermally and optically stimulated luminescent detectors, indicating the direction of ongoing research. It shows that passive dosemeters are still a very active field. Active dosemeters will not be discussed with the exception of new developments in microdosimetric measurements [new types of tissue equivalent proportional counters (TEPCs)]. The TEPC is unique in its ability to provide a simultaneous determination of neutron / charged particle / gamma ray doses, or dose equivalents using a single detector.
Radiation Measurements, 2012
Radiation Measurements, 2010
Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow ... more Energy-resolved optically stimulated luminescence (OSL) spectra and thermoluminescence (TL) glow curves of a powder sample of YPO 4 :Ce 3þ ,Sm 3þ were measured to investigate the nature of the trapping centre and to locate its energy level relative to the valence and conduction bands of the YPO 4 host. The high-temperature glow peak could unequivocally be assigned to Sm 2þ (thus Sm 3þ acts as an electron trap). The trap depth of this centre, as derived from the OSL excitation spectra, is in good agreement with the Dorenbos model prediction. The OSL excitation spectra also reveal excited states of Sm 2þ well below the conduction band. These excited states produce a broadening of the high-temperature TL glow peak and also cause the activation energy determined by the Hoogenstraten method to underestimate the trap depth.
Radiation Measurements, 2009
A mathematical transformation based on differentiation is introduced that converts a Continuous W... more A mathematical transformation based on differentiation is introduced that converts a Continuous Wave Optically Stimulated Luminescence (CW-OSL) decay curve composed of a number of exponentials into a spectrum like curve with different peaks. Peak areas of the transformed curve are equal to the time integrated OSL of the exponentials. It is shown that the peaks of the transformed curve are more separated then the original decay curve components. The transformation is applied to computer generated OSL curves and to measured CW-OSL decay curves of three different quartz samples. Advantages and limitations of this differentiation analysis method are discussed.
Materials (Basel, Switzerland), Jan 26, 2017
Thermally stimulated luminescence (TSL) is known as a technique used in radiation dosimetry and d... more 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. First, some basic characteristics and a theoretical background of the phenomenon are given. Next, methods and difficulties in extracting trapping parameters are addressed. Then, the instrumentation needed to measure the luminescence, both as a function of temperature and wavelength, is described. Finally, a series of very diverse examples is given to illustrate how TSL has been used in the determination of energy levels of defects, in the research of persistent luminescence phosphors, and in phenomena like band gap engineering, tunnelling, photosynthesis, and thermal quenching. It is concluded that in the field of lum...
The journal of physical chemistry. C, Nanomaterials and interfaces, Jan 27, 2017
Two different charge carrier trapping processes have been investigated in RE2O2S:Ln(3+) (RE = La,... more Two different charge carrier trapping processes have been investigated in RE2O2S:Ln(3+) (RE = La, Gd, Y, and Lu; Ln = Ce, Pr, and Tb) and RE2O2S:M (M = Ti(4+) and Eu(3+)). 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(4+), Pr(4+), or Tb(4+) via the conduction band. On the other hand, Ti(4+) and Eu(3+) act as recombination centers and electron trapping centers while host intrinsic defects act as hole trapping centers. For these codopants we find evidence that recombination is by means of hole release instead of electron release. The released holes recombine with the trapped electrons on Ti(3+) or Eu(2+) and yield broad Ti(4+) yellow-red charge transfer (CT) emission or characteristic Eu(3+) 4f-4f emission. We will conclude that the afterglow in Y2O2S:Ti(4+), Eu(3+) is due to hole release instead of more common ele...
Review of Scientific Instruments, 1993
ABSTRACT
Journal of Applied Physics, 2008
Tm͒ are presented and used together with the empirical Dorenbos model in order to establish the 4... more Tm͒ are presented and used together with the empirical Dorenbos model in order to establish the 4f energy level positions of all tri-and divalent lanthanide ions doped in NaLaF 4. The information will be presented in the form of an energy level diagram. It is shown that in addition to this diagram only two assumptions, viz., the presence of two host related electron traps and the presence of V k-centers, are necessary for explaining the lanthanide-specific TL glow curves of both Ln mono-and Ce-Ln codoped NaLaF 4 .
The effects of the cooling rate alpha and heating rate beta on trapping parameters and thermolumi... more The effects of the cooling rate alpha and heating rate beta on trapping parameters and thermoluminescent (TL) glow peak intensities in LiF:Mg, Ti(TLD-100) crystals have been studied by glow curve fitting from room temperature to 500 K. It is found that under the investigated circumstances (1 K min-1< alpha < 5000 K min-1, 0.12 K s-1 < beta FOM>0.2%). Glow
We investigate both theoretically and experimentally the effect of stimulation mode on the separa... more We investigate both theoretically and experimentally the effect of stimulation mode on the separation of quartz optically stimulated luminescence (OSL) components. We find that, when assuming first-order kinetics with the detrapping probability proportional to stimulation intensity, the OSL signal is a function of the cumulative stimulation energy and not affected by the stimulation mode. This is confirmed by close correspondence between continuous wave (CW), linearly modulated (LM) and hyperbolically modulated (HM) OSL data for some of the samples studied. For other samples the data obtained using LM stimulation differ from that obtained using the other stimulation modes. This may be due to a contribution to the OSL signal from feldspars, or it may indicate that the behaviour of these samples is not adequately described by first-order kinetics. We suggest that CW stimulation is the method of choice for dating purposes as it allows the fastest readout with the greatest signal-to-noise ratio, and because it has a constant background. HM stimulation provides a good alternative when higher resolution is needed for the initial part of the shine-down curve.
Quaternary Geochronology, Dec 31, 2007
Infrared-stimulated luminescence (IRSL) dating of feldspars has the potential to date deposits be... more Infrared-stimulated luminescence (IRSL) dating of feldspars has the potential to date deposits beyond the age range of quartz optical (OSL) dating. Successful application of feldspar IRSL dating is, however, often precluded due to anomalous-fading, the tunnelling of electrons from one defect site to another. In this paper we test procedures proposed for anomalous-fading correction by comparing feldspar IRSL and quartz OSL dating results on a suite of samples from continental deposits from the southeastern Netherlands. We find ...
The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stim... more The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stimulation power (CW-OSL) is a featureless decay curve where underlying components cannot be identified easily. Visual interpretation of quartz OSL signals is easier if signals are shown in spectrum-like form. This can be achieved either through ramped stimulation, or by transforming a measured CW-OSL curve into a pseudo OSL curve. We show that both give similar results, but that transformation should be preferred as CW-OSL provides best signal-to-noise ratios. We present different transformation methods to obtain pseudo OSL curves and discuss the advantages and disadvantages of each method. In addition, we show that different pseudo OSL transformations can be used to emphasize specific aspects of the OSL signal. We conclude that transformation of CW-OSL to pseudo hyperbolically modulated OSL provides the most useful visualization of the quartz fast OSL component. Pseudo parabolic modulated OSL is the transformation of choice for showing the slow component(s). The pseudo OSL curves can be used for rapid visual inspection of the relative contribution of the OSL components prior to further analysis.
Thermoluminescence (TL) emission spectra and TL glow curves of powder samples of YPO 4 :Ce 3+ , L... more Thermoluminescence (TL) emission spectra and TL glow curves of powder samples of YPO 4 :Ce 3+ , Ln 3+ (Ln 3+ = Nd 3+ , Sm 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+) were measured in order to investigate the nature of the trapping centres and to locate the lanthanide energy levels relative to the valence and conduction bands of the YPO 4 host. Trap depths were determined by three different TL techniques (simple formula, various heating rate method and glow curve fitting) and compared with an earlier developed predictive energy level scheme. The nature of the trapping centres agrees with that predicted by the energy level scheme. Further, the trend of trap depths of the divalent lanthanides (Ln 2+ = Nd 2+ , Sm 2+ , Dy 2+ , Ho 2+ , Er 2+ , Tm 2+) agrees very well with the trend of levels determined by three different thermoluminescent techniques. It is concluded that the energy level scheme can help in the development of new TL materials suitable in dosimetry.
Nucl Instrum Meth Phys Res a, 2003
We have studied the operation of two different Gas Electron Multiplier (GEM) structures in both m... more We have studied the operation of two different Gas Electron Multiplier (GEM) structures in both methane and propane based Tissue-Equivalent (TE) gases at different pressures varying from 0.1 to 1 atm. This work was motivated to explore the possibility of using a GEM for a new type of Tissue Equivalent Proportional Counter. In methane based TE gas, a maximum safe GEM gain of 1.5×10 3 has been reached while in propane based TE gas this is 6×10 3. These maxima have been reached at different gas pressures depending on GEM structure and TE gas. Furthermore, we observed a decrease of the GEM gain in time before it becomes stable. Charge up/polarisation effects can explain this.
Radiation Measurements, 2008
Physical Review B Condensed Matter and Materials Physics, 2009
The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stim... more The optically stimulated luminescence (OSL) signal of natural quartz measured under constant stimulation power (CW-OSL) is a featureless decay curve where underlying components cannot be identified easily. Visual interpretation of quartz OSL signals is easier if signals are shown in spectrum-like form. This can be achieved either through ramped stimulation, or by transforming a measured CW-OSL curve into a pseudo OSL curve. We show that both give similar results, but that transformation should be preferred as CW-OSL provides best signal-to-noise ratios. We present different transformation methods to obtain pseudo OSL curves and discuss the advantages and disadvantages of each method. In addition, we show that different pseudo OSL transformations can be used to emphasize specific aspects of the OSL signal. We conclude that transformation of CW-OSL to pseudo hyperbolically modulated OSL provides the most useful visualization of the quartz fast OSL component. Pseudo parabolic modulated OSL is the transformation of choice for showing the slow component(s). The pseudo OSL curves can be used for rapid visual inspection of the relative contribution of the OSL components prior to further analysis.
Radiat Meas, 2008
The consequences of irradiating ∅1in×1inLaBr3:5%Ce crystals with 0.1–100kGy gamma radiation have ... more The consequences of irradiating ∅1in×1inLaBr3:5%Ce crystals with 0.1–100kGy gamma radiation have been investigated. The material displays lower photoelectron yield and poorer energy resolution after exposure to a 60Co source. The magnitude of the damage is larger in a packed scintillator. In addition to a prompt effect following gamma irradiation, consisting of a deterioration in both photoelectron yield and energy resolution,