Radu A Vasilache | University of Bucharest (original) (raw)

Papers by Radu A Vasilache

Research paper thumbnail of Measurement with Hp(10) and H*(10) secondary standard chambers at NILPRP 7 MeV linear accelerator

Radiation Measurements, 2010

A secondary standard chamber for measuring the conventionally true value of the personal dose equ... more A secondary standard chamber for measuring the conventionally true value of the personal dose equivalent, Hp(10), was developed by Arckerhold et al. at Physikalisch Technische Bundesanstalt (PTB). This type of chamber together with a secondary standard ionization chamber for direct measurement of ambient dose equivalent, H*(10), both outfitting the Secondary Standard Dosimetry Laboratory (SSDL), were used for area monitoring at the NILPRP 7 MeV Linear Accelerator. Measurement results, for both ICRU operational quantities, are presented in this paper.

Research paper thumbnail of New setup for basic radiobiology studies using a 3 MV TandetronTM: Design and developments

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Research paper thumbnail of Cancer risk due to Cs-137 and Sr-90 dietary intake after the Chernobyl accident

On the 26 of April, 1986, a major accident occurred at the fourth reactor of the Chernobyl nuclea... more On the 26 of April, 1986, a major accident occurred at the fourth reactor of the Chernobyl nuclear power plant, in Ukraine. Soon after the accident, on May 1*, the radioactive cloud reached Romania. The meteorological conditions (rainy weather) lead to important fallout over our country. The most important radionuclides carried by the radioactive plume over Romania were I, Cs, Cs and Sr. As in many other countries, in the first days, I l had the main contribution to the irradiation dose released to the population. After its decay, and the decay of the other short-lived radionuclides, Cs and Sr remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. Assessments of radiation doses to people living in the Bucharest area (south-east of Romania the area studied in this paper) have utilized data obtained from measurement of Cs and Sr content in dietary intake samples for a number of subjec...

Research paper thumbnail of Radiation Protection and Climate Change: How Do the Dose Response Models Influence the Choices of Solutions to Mitigate Climate Problems

Research paper thumbnail of Evaluation of a new experimental setup for radiobiology experiments at the E1 area of the ELI-NP building using FLUKA

Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which... more Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which use ultrahigh power lasers (10 PW in the first case, 1 PW in the second) for a wide array of research activities. One of the declared purposes of the ELI-NP project is to explore the possibility of developing new techniques in proton therapy by using laser- accelerated beams. However, it is highly probable that some of the initial experiments will be directed towards gaining more insight into the radiobiology of proton therapy and the factors that influence the relative biological effectiveness of the beam. The present paper analyses the feasibility of such radiobiology experiments at the E1 area of the ELI-NP building, using proton beams with maximum energies of up to 500 MeV. The FLUKA code is used to simulate a case in which a proton beam with 40 0 divergence is collimated on a 10-cm-diameter exit window. The beam is used to irradiate a parallelepipedal water phantom placed in air at a distance of 10 cm from the window. The phantom has a 20x20 cm 2 cross area and a depth of 10 cm. We present the results regarding beam homogeneity and symmetry at the phantom entrance side, as well as the depth dose curves and the depth LET curves, both for primary protons and for all ionizing particles. We conclude by showing how this information can be used for designing the setup of radiobiology experiments at an ultrahigh power laser area.

Research paper thumbnail of Dose - Response Relationships: from the LNT Model to the Adaptive Response Models and their Possible Implications on the Radiological Protection Regulations

Research paper thumbnail of A New Array Detector for Dose Measurements in Laser Generated Ultrashort Proton Beams Used for Radiobiology Experiments

One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lase... more One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lasers, is to provide more insight regarding the biological effectiveness of the proton beams. One major problem is the in-beam dosimetry for these experiments, not in the least due to the extreme shortness of the pulses. Due to the specifics of the laser pulse, the proton beams generated by laser acceleration have a lenght of only a few nanoseconds, which means that measurements with ion chambers will be affected by large recombination correction factors. Measuring those recombination factors through the usual method is not an option because the laser frequency is rather low (0.1 Hz is to be achieved) and, at least in the begining, the pulses will not be highly repeatable). Therefore, we have developed an array of four chambers, each polarised at a different voltage. The chamber array is now being tested in various charged particle fields, and the present paper shows the results obtained in a 19 MeV proton beam from the TR19 cyclotron from NIPNE, Magurele. In order to determine the distance between the chambers, FLUKA simulations were used to calculate the reciprocal influences of the four chambers. The recombination correction factor was then determined in the 19 MeV beam, first by the classical method than using the array detector and the differences between the two are presented. We can safely conclude that the array can be used with good results for the dosimetry in ultrashort pulses of proton beams.

Research paper thumbnail of Possibilities of Improving the 3D Gamma Index Use for Treatment Plan Verifications

Research paper thumbnail of Characteristics of TLD-100 Fading and its Influence on the Calibration of Personal Dosemeters

Radiation Protection Dosimetry, 1999

The fading of the thermoluminescent phosphors used as dosemeters is of great importance when it c... more The fading of the thermoluminescent phosphors used as dosemeters is of great importance when it comes to calibrating a dosimetric system. The results of a series of experiments performed in order to determine some fading characteristics of TLD-100 (Harshaw Chemical Co.) are presented. The experiment was performed using two batches of dosemeters that were irradiated with X rays simultaneously and with the same dose. One of the two batches was used to determine the thermal fading at room temperature, and the other one to determine the combined optical and thermal fading. The results indicated that, after the low temperature peaks had faded out, the response of the dosemeters exposed to light became quite stable, with a very low fading. The signal of the dosemeters kept away from light continued to fade down to a lower level than the signal of the dosemeters exposed to light. The results of other experiments involving UV irradiation after the irradiation with X rays, and their implications for the calibration of personal dosemeters are also presented.

Research paper thumbnail of The Danube Delta system during the past 12 ka years: new 14C dating of the deltaic sediments

Research paper thumbnail of Considerations on the composition and spectra of the secondary radiation fields inside the E1 experimental area at ELI-NP

Journal of Physics: Conference Series, 2020

At the new ultrahigh power laser facility ELI NP, experiments on the interaction of high power la... more At the new ultrahigh power laser facility ELI NP, experiments on the interaction of high power lasers and matter will be conducted. These experiments are expected to produce beams of highly energetic particles resulting in secondary radiation fields which will be highly complex and rather difficult to measure given their specifics (extremely short bursts, with time widths in the range of nanoseconds). The ELIFLUKA project was started to assess the doses in the areas surrounding the experimental halls, to evaluate the efficiency of the existing shielding solutions, to propose, if necessary, their optimization, and give optimal ways to monitor the radiation fields that might affect the facility personnel. The present paper is focused on the results concerning the composition and the spectra of the secondary radiation fields inside the E’ experimental hall. A complex FLUKA geometry of the El area was built according to the real design of the experimental hall. With FLUKA we calculated ...

Research paper thumbnail of A Prototype Detector Array for Measurements in Laser Accelerated Charged Particle Beams

Journal of Physics: Conference Series, 2020

In all the future applications of the laser accelerated beams (as generated in the ELI and CETAL ... more In all the future applications of the laser accelerated beams (as generated in the ELI and CETAL projects) in-beam dose measurements will be needed. The gold standard in dose measurement remain the ion chambers, but for the beams we intend to measure they do present some limitations given be the large number of corrections to be applied in order to calculate a correct dose from the measured charge. The ELIDOSE project is addressing these problems by proposing an array detector that would allow the simultaneous measurement of the recombination and polarity corrections, as well as of the dose – the QUADRO-fm (Quad Detector for RecOmbination factor measurement). The prototype detector consists of 4 identical ion chambers mounted together in a PMMA frame and the project analyses its response to various charged particle beams and the reciprocal influences of the chambers on each other. This reciprocal influences of the four chambers have been studied in well characterised therapy electro...

Research paper thumbnail of Eye Protontherapy: Proposed Feasibility Plan

Research paper thumbnail of A proposed multi-detector array for the diagnosis and dosimetry of laser accelerated proton beams

Research paper thumbnail of The Development of a Novel Array Detector for Overcoming the Dosimetry Challenges of Measuring in Very Short Pulsed Charged Particle Beams: The Elidose Project

In-beam dose measurements are paramount for any application seeking to harness the effects of the... more In-beam dose measurements are paramount for any application seeking to harness the effects of the radiation beam, so all the future applications of the laser accelerated beams (as generated in the ELI and CETAL projects) will need such measurements. With a very long history in measuring doses in charged particle beams, the medical and industrial applications setup a number of methods that could be also used for the dosimetry of the beams generated by laser pulses. Dose measurements rely heavily on what is seen as the gold standard in dose measurement: the ion chambers. Ion chambers have both limitations and advantages, and in our case the disadvantage could be the large number of corrections to be applied in order to calculate a correct dose from the measured charge. The ELIDOSE project tries to address these problems by proposing an array detector that would allow the simultaneous measurement of the recombination and polarity corrections, and of the dose. The detector consists of f...

Research paper thumbnail of Radiological Safety Assessment for the Experimental Area of a Hyper-Intense Laser with Peak—Power of 1PW—CETAL

Radiation Protection Dosimetry, 2016

RADIOLOGICAL SAFETY ASSESSMENT FOR THE EXPERIMENTAL AREA OF A HYPER-INTENSE LASER WITH PEAK—POWER... more RADIOLOGICAL SAFETY ASSESSMENT FOR THE EXPERIMENTAL AREA OF A HYPER-INTENSE LASER WITH PEAK—POWER OF 1PW—CETAL M. G. Florescu1,2, O. G. Duliu3,4,*, D. Pantazi1 , C. M. Ticos5 , D. Sporea5 , R. Vasilache6 , V. Ionescu1 and M. Oane5 1 Center of Technology and Engineering for Nuclear Projects, 409 Atomistilor Str., PO Box 5204-MG-4, Magurele (Ilfov) 077125, Romania 2 University of Bucharest, Faculty of Physics, Doctoral School on Physics, 405 Atomistilor Str., PO Box MG-11, Magurele (Ilfov) 077125, Romania 3 University of Bucharest, Faculty of Physics, Department of Structure of Matter, Earth and Atmospheric Physics and Astrophysics, 405 Atomistilor Str., PO Box MG-11, Magurele (Ilfov) 077125, Romania 4 Frank Neutron Physics Laboratory, Joint Institute for Nuclear Research, 141980 Dubna, Russian Federation 5 National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Str., 077125 Magurele (Ilfov), Romania 6 Canberra Packard SRL, 18 Clejani Str., 051036 Bucharest, Romania *Corresponding author: o.duliu@upcmail.ro Ultra-high intensity lasers in use are connected with ionizing radiation sources that raise a real concern in relation to installa- tions, personnel, population and environment protection. The shielding of target areas in these facilities has to be evaluated from the conceptual stage of the building design. The sizing of the protective concrete walls was determined using computer codes such as Fluka. For the experiments to be carried out in the facility of the Center for Advanced Laser Technologies (CETAL), both proton beams with the energy of 100 MeV and electron beams with 300 MeV energy were considered to cal- culate the dimensions of structural shielding and to establish technical solutions fulfilling the radiation protection constraints imposed by the National Commission for Nuclear Activities Control.

Research paper thumbnail of Proposal of a FLUKA-based radiation monitoring system for the laser driven electron acceleration area at ELI-NP

Radiation Physics and Chemistry

A R T I C L E I N F O Keywords: FLUKA simulations Dose and fluence maps Radiation protection High... more A R T I C L E I N F O Keywords: FLUKA simulations Dose and fluence maps Radiation protection High power lasers A B S T R A C T FLUKA simulations were used to design a dosimetry monitoring system for the typical electron acceleration experiments in the E6 area of the ELI-NP building. The FLUKA geometry of the E6 experimental area was built by using data extracted from the latest available version of the corresponding Catia file, including all the building and beamline transport elements. Based on that geometry we calculated H*(10) in a Cartesian binning over E6 and neighbouring areas for the worst case scenario: a 38 GeV Gaussian electron source term. The fluence rates of the secondary prompt radiation field components were mapped throughout the E6 experimental area. The results were used to determine the most important contributor to the dose and the areas with the highest exposure, as well as the positioning of the detectors for radiation monitoring. We propose solutions for some practical issues: proper choice of the detector type and proper detector positioning in accordance with the characteristics of the radiation field (dose range, field components, energy ranges).

Research paper thumbnail of The ELIDOSE Project: Dosimetry for laser accelerated charged particle beams

Research Outreach

B right laser pulses are now being used in a wide variety of scientific experiments. By concentra... more B right laser pulses are now being used in a wide variety of scientific experiments. By concentrating large numbers of photons over small areas, the pulses can subject small samples to huge amounts of energy, making them suitable for tasks ranging from analysing the properties of fundamental particles, to probing responses in biological tissues. The Extreme Light Infrastructure (ELI) project is a pan-European collaboration which uses high intensity laser beams as a basis for a wide array of experiments.

Research paper thumbnail of The influence of time-temperature profiles on the behavior of TLD-100 as personal dosemeter

Research paper thumbnail of Generation of intense relativistic electron beams by 1 PW laser-target interactions at “CETAL” facility

Research paper thumbnail of Measurement with Hp(10) and H*(10) secondary standard chambers at NILPRP 7 MeV linear accelerator

Radiation Measurements, 2010

A secondary standard chamber for measuring the conventionally true value of the personal dose equ... more A secondary standard chamber for measuring the conventionally true value of the personal dose equivalent, Hp(10), was developed by Arckerhold et al. at Physikalisch Technische Bundesanstalt (PTB). This type of chamber together with a secondary standard ionization chamber for direct measurement of ambient dose equivalent, H*(10), both outfitting the Secondary Standard Dosimetry Laboratory (SSDL), were used for area monitoring at the NILPRP 7 MeV Linear Accelerator. Measurement results, for both ICRU operational quantities, are presented in this paper.

Research paper thumbnail of New setup for basic radiobiology studies using a 3 MV TandetronTM: Design and developments

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Research paper thumbnail of Cancer risk due to Cs-137 and Sr-90 dietary intake after the Chernobyl accident

On the 26 of April, 1986, a major accident occurred at the fourth reactor of the Chernobyl nuclea... more On the 26 of April, 1986, a major accident occurred at the fourth reactor of the Chernobyl nuclear power plant, in Ukraine. Soon after the accident, on May 1*, the radioactive cloud reached Romania. The meteorological conditions (rainy weather) lead to important fallout over our country. The most important radionuclides carried by the radioactive plume over Romania were I, Cs, Cs and Sr. As in many other countries, in the first days, I l had the main contribution to the irradiation dose released to the population. After its decay, and the decay of the other short-lived radionuclides, Cs and Sr remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. Assessments of radiation doses to people living in the Bucharest area (south-east of Romania the area studied in this paper) have utilized data obtained from measurement of Cs and Sr content in dietary intake samples for a number of subjec...

Research paper thumbnail of Radiation Protection and Climate Change: How Do the Dose Response Models Influence the Choices of Solutions to Mitigate Climate Problems

Research paper thumbnail of Evaluation of a new experimental setup for radiobiology experiments at the E1 area of the ELI-NP building using FLUKA

Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which... more Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which use ultrahigh power lasers (10 PW in the first case, 1 PW in the second) for a wide array of research activities. One of the declared purposes of the ELI-NP project is to explore the possibility of developing new techniques in proton therapy by using laser- accelerated beams. However, it is highly probable that some of the initial experiments will be directed towards gaining more insight into the radiobiology of proton therapy and the factors that influence the relative biological effectiveness of the beam. The present paper analyses the feasibility of such radiobiology experiments at the E1 area of the ELI-NP building, using proton beams with maximum energies of up to 500 MeV. The FLUKA code is used to simulate a case in which a proton beam with 40 0 divergence is collimated on a 10-cm-diameter exit window. The beam is used to irradiate a parallelepipedal water phantom placed in air at a distance of 10 cm from the window. The phantom has a 20x20 cm 2 cross area and a depth of 10 cm. We present the results regarding beam homogeneity and symmetry at the phantom entrance side, as well as the depth dose curves and the depth LET curves, both for primary protons and for all ionizing particles. We conclude by showing how this information can be used for designing the setup of radiobiology experiments at an ultrahigh power laser area.

Research paper thumbnail of Dose - Response Relationships: from the LNT Model to the Adaptive Response Models and their Possible Implications on the Radiological Protection Regulations

Research paper thumbnail of A New Array Detector for Dose Measurements in Laser Generated Ultrashort Proton Beams Used for Radiobiology Experiments

One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lase... more One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lasers, is to provide more insight regarding the biological effectiveness of the proton beams. One major problem is the in-beam dosimetry for these experiments, not in the least due to the extreme shortness of the pulses. Due to the specifics of the laser pulse, the proton beams generated by laser acceleration have a lenght of only a few nanoseconds, which means that measurements with ion chambers will be affected by large recombination correction factors. Measuring those recombination factors through the usual method is not an option because the laser frequency is rather low (0.1 Hz is to be achieved) and, at least in the begining, the pulses will not be highly repeatable). Therefore, we have developed an array of four chambers, each polarised at a different voltage. The chamber array is now being tested in various charged particle fields, and the present paper shows the results obtained in a 19 MeV proton beam from the TR19 cyclotron from NIPNE, Magurele. In order to determine the distance between the chambers, FLUKA simulations were used to calculate the reciprocal influences of the four chambers. The recombination correction factor was then determined in the 19 MeV beam, first by the classical method than using the array detector and the differences between the two are presented. We can safely conclude that the array can be used with good results for the dosimetry in ultrashort pulses of proton beams.

Research paper thumbnail of Possibilities of Improving the 3D Gamma Index Use for Treatment Plan Verifications

Research paper thumbnail of Characteristics of TLD-100 Fading and its Influence on the Calibration of Personal Dosemeters

Radiation Protection Dosimetry, 1999

The fading of the thermoluminescent phosphors used as dosemeters is of great importance when it c... more The fading of the thermoluminescent phosphors used as dosemeters is of great importance when it comes to calibrating a dosimetric system. The results of a series of experiments performed in order to determine some fading characteristics of TLD-100 (Harshaw Chemical Co.) are presented. The experiment was performed using two batches of dosemeters that were irradiated with X rays simultaneously and with the same dose. One of the two batches was used to determine the thermal fading at room temperature, and the other one to determine the combined optical and thermal fading. The results indicated that, after the low temperature peaks had faded out, the response of the dosemeters exposed to light became quite stable, with a very low fading. The signal of the dosemeters kept away from light continued to fade down to a lower level than the signal of the dosemeters exposed to light. The results of other experiments involving UV irradiation after the irradiation with X rays, and their implications for the calibration of personal dosemeters are also presented.

Research paper thumbnail of The Danube Delta system during the past 12 ka years: new 14C dating of the deltaic sediments

Research paper thumbnail of Considerations on the composition and spectra of the secondary radiation fields inside the E1 experimental area at ELI-NP

Journal of Physics: Conference Series, 2020

At the new ultrahigh power laser facility ELI NP, experiments on the interaction of high power la... more At the new ultrahigh power laser facility ELI NP, experiments on the interaction of high power lasers and matter will be conducted. These experiments are expected to produce beams of highly energetic particles resulting in secondary radiation fields which will be highly complex and rather difficult to measure given their specifics (extremely short bursts, with time widths in the range of nanoseconds). The ELIFLUKA project was started to assess the doses in the areas surrounding the experimental halls, to evaluate the efficiency of the existing shielding solutions, to propose, if necessary, their optimization, and give optimal ways to monitor the radiation fields that might affect the facility personnel. The present paper is focused on the results concerning the composition and the spectra of the secondary radiation fields inside the E’ experimental hall. A complex FLUKA geometry of the El area was built according to the real design of the experimental hall. With FLUKA we calculated ...

Research paper thumbnail of A Prototype Detector Array for Measurements in Laser Accelerated Charged Particle Beams

Journal of Physics: Conference Series, 2020

In all the future applications of the laser accelerated beams (as generated in the ELI and CETAL ... more In all the future applications of the laser accelerated beams (as generated in the ELI and CETAL projects) in-beam dose measurements will be needed. The gold standard in dose measurement remain the ion chambers, but for the beams we intend to measure they do present some limitations given be the large number of corrections to be applied in order to calculate a correct dose from the measured charge. The ELIDOSE project is addressing these problems by proposing an array detector that would allow the simultaneous measurement of the recombination and polarity corrections, as well as of the dose – the QUADRO-fm (Quad Detector for RecOmbination factor measurement). The prototype detector consists of 4 identical ion chambers mounted together in a PMMA frame and the project analyses its response to various charged particle beams and the reciprocal influences of the chambers on each other. This reciprocal influences of the four chambers have been studied in well characterised therapy electro...

Research paper thumbnail of Eye Protontherapy: Proposed Feasibility Plan

Research paper thumbnail of A proposed multi-detector array for the diagnosis and dosimetry of laser accelerated proton beams

Research paper thumbnail of The Development of a Novel Array Detector for Overcoming the Dosimetry Challenges of Measuring in Very Short Pulsed Charged Particle Beams: The Elidose Project

In-beam dose measurements are paramount for any application seeking to harness the effects of the... more In-beam dose measurements are paramount for any application seeking to harness the effects of the radiation beam, so all the future applications of the laser accelerated beams (as generated in the ELI and CETAL projects) will need such measurements. With a very long history in measuring doses in charged particle beams, the medical and industrial applications setup a number of methods that could be also used for the dosimetry of the beams generated by laser pulses. Dose measurements rely heavily on what is seen as the gold standard in dose measurement: the ion chambers. Ion chambers have both limitations and advantages, and in our case the disadvantage could be the large number of corrections to be applied in order to calculate a correct dose from the measured charge. The ELIDOSE project tries to address these problems by proposing an array detector that would allow the simultaneous measurement of the recombination and polarity corrections, and of the dose. The detector consists of f...

Research paper thumbnail of Radiological Safety Assessment for the Experimental Area of a Hyper-Intense Laser with Peak—Power of 1PW—CETAL

Radiation Protection Dosimetry, 2016

RADIOLOGICAL SAFETY ASSESSMENT FOR THE EXPERIMENTAL AREA OF A HYPER-INTENSE LASER WITH PEAK—POWER... more RADIOLOGICAL SAFETY ASSESSMENT FOR THE EXPERIMENTAL AREA OF A HYPER-INTENSE LASER WITH PEAK—POWER OF 1PW—CETAL M. G. Florescu1,2, O. G. Duliu3,4,*, D. Pantazi1 , C. M. Ticos5 , D. Sporea5 , R. Vasilache6 , V. Ionescu1 and M. Oane5 1 Center of Technology and Engineering for Nuclear Projects, 409 Atomistilor Str., PO Box 5204-MG-4, Magurele (Ilfov) 077125, Romania 2 University of Bucharest, Faculty of Physics, Doctoral School on Physics, 405 Atomistilor Str., PO Box MG-11, Magurele (Ilfov) 077125, Romania 3 University of Bucharest, Faculty of Physics, Department of Structure of Matter, Earth and Atmospheric Physics and Astrophysics, 405 Atomistilor Str., PO Box MG-11, Magurele (Ilfov) 077125, Romania 4 Frank Neutron Physics Laboratory, Joint Institute for Nuclear Research, 141980 Dubna, Russian Federation 5 National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Str., 077125 Magurele (Ilfov), Romania 6 Canberra Packard SRL, 18 Clejani Str., 051036 Bucharest, Romania *Corresponding author: o.duliu@upcmail.ro Ultra-high intensity lasers in use are connected with ionizing radiation sources that raise a real concern in relation to installa- tions, personnel, population and environment protection. The shielding of target areas in these facilities has to be evaluated from the conceptual stage of the building design. The sizing of the protective concrete walls was determined using computer codes such as Fluka. For the experiments to be carried out in the facility of the Center for Advanced Laser Technologies (CETAL), both proton beams with the energy of 100 MeV and electron beams with 300 MeV energy were considered to cal- culate the dimensions of structural shielding and to establish technical solutions fulfilling the radiation protection constraints imposed by the National Commission for Nuclear Activities Control.

Research paper thumbnail of Proposal of a FLUKA-based radiation monitoring system for the laser driven electron acceleration area at ELI-NP

Radiation Physics and Chemistry

A R T I C L E I N F O Keywords: FLUKA simulations Dose and fluence maps Radiation protection High... more A R T I C L E I N F O Keywords: FLUKA simulations Dose and fluence maps Radiation protection High power lasers A B S T R A C T FLUKA simulations were used to design a dosimetry monitoring system for the typical electron acceleration experiments in the E6 area of the ELI-NP building. The FLUKA geometry of the E6 experimental area was built by using data extracted from the latest available version of the corresponding Catia file, including all the building and beamline transport elements. Based on that geometry we calculated H*(10) in a Cartesian binning over E6 and neighbouring areas for the worst case scenario: a 38 GeV Gaussian electron source term. The fluence rates of the secondary prompt radiation field components were mapped throughout the E6 experimental area. The results were used to determine the most important contributor to the dose and the areas with the highest exposure, as well as the positioning of the detectors for radiation monitoring. We propose solutions for some practical issues: proper choice of the detector type and proper detector positioning in accordance with the characteristics of the radiation field (dose range, field components, energy ranges).

Research paper thumbnail of The ELIDOSE Project: Dosimetry for laser accelerated charged particle beams

Research Outreach

B right laser pulses are now being used in a wide variety of scientific experiments. By concentra... more B right laser pulses are now being used in a wide variety of scientific experiments. By concentrating large numbers of photons over small areas, the pulses can subject small samples to huge amounts of energy, making them suitable for tasks ranging from analysing the properties of fundamental particles, to probing responses in biological tissues. The Extreme Light Infrastructure (ELI) project is a pan-European collaboration which uses high intensity laser beams as a basis for a wide array of experiments.

Research paper thumbnail of The influence of time-temperature profiles on the behavior of TLD-100 as personal dosemeter

Research paper thumbnail of Generation of intense relativistic electron beams by 1 PW laser-target interactions at “CETAL” facility

Research paper thumbnail of EVALUATION OF A NEW EXPERIMENTAL SETUP FOR RADIOBIOLOGY EXPERIMENTS AT THE E1 AREA OF THE ELI-NP BUILDING USING FLUKA

Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which... more Currently there are two state-of-art research infrastructures in Romania, ELI-NP and CETAL, which use ultrahigh power lasers (10 PW in the first case, 1 PW in the second) for a wide array of research activities. One of the declared purposes of the ELI-NP project is to explore the possibility of developing new techniques in proton therapy by using laser-
accelerated beams. However, it is highly probable that some of the initial experiments will be directed towards gaining more insight into the radiobiology of proton therapy and the factors that influence the relative biological effectiveness of the beam.
The present paper analyses the feasibility of such radiobiology experiments at the E1 area of the ELI-NP building, using proton beams with maximum energies of up to 500 MeV.
The FLUKA code is used to simulate a case in which a proton beam with 40 0 divergence is collimated on a 10-cm-diameter exit window. The beam is used to irradiate a parallelepipedal water phantom placed in air at a distance of 10 cm from the window. The phantom has a 20x20 cm 2 cross area and a depth of 10 cm. We present the results regarding beam homogeneity and symmetry at the phantom entrance side, as well as the depth dose curves and the depth LET curves, both for primary protons and for all ionizing particles. We conclude by showing how this information can be used for designing the setup of radiobiology experiments at an ultrahigh power laser area.

Research paper thumbnail of A NEW ARRAY DETECTOR FOR DOSE MEASUREMENTS IN LASER GENERATED ULTRASHORT PROTON BEAMS USED FOR RADIOBIOLOGY EXPERIMENTS

One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lase... more One of the research directions at the ELI-NP research infrastructure in Romania, using 10 PW lasers, is to provide more insight regarding the biological effectiveness of the proton beams. One major problem is the in-beam dosimetry for these experiments, not in the least due to the extreme shortness of the pulses. Due to the specifics of the laser pulse, the proton beams generated by laser acceleration have a lenght of only a few nanoseconds, which means that measurements with ion chambers will be affected by large recombination correction factors. Measuring those recombination factors through the usual method is not an option because the laser frequency is rather low (0.1 Hz is to be achieved) and, at least in the begining, the pulses will not be highly repeatable).
Therefore, we have developed an array of four chambers, each polarised at a different voltage. The chamber array is now being tested in various charged particle fields, and the present paper shows the results obtained in a 19 MeV proton beam from the TR19 cyclotron from NIPNE, Magurele. In order to determine the distance between the chambers, FLUKA simulations were used to calculate the reciprocal influences of the four chambers. The recombination correction factor was then determined in the 19 MeV beam, first by the classical method than using the array detector and the differences between the two are presented. We can safely conclude that the array can be used with good results for the dosimetry in ultrashort pulses of proton beams.