Cumulative Beam Breakup with Time-Dependent Parameters

CERN Document Server

Delayen, J R

2004-01-01

A general analytical formalism developed recently for cumulative beam breakup (BBU) in linear accelerators with arbitrary beam current profile and misalignments [1] is extended to include time-dependent parameters such as energy chirp or rf focusing in order to reduce BBU-induced instabilities and emittance growth. Analytical results are presented and applied to practical accelerator configurations.

The beam-beam limit in asymmetric colliders: Optimization of the B-factory parameter base

International Nuclear Information System (INIS)

Tennyson, J.L.

1990-01-01

This paper presents a general theory of the beam-beam limit in symmetric and asymmetric lepton ring colliders. It shows how the beam-beam limit in these accelerators affects the maximum attainable luminosity and presents a specific algorithm for parameter base optimization. It is shown that the special problems inherent in asymmetric colliders derive not from the asymmetry, but from the fact that the two beams must be in different rings. Computer simulation experiments are used to demonstrate the various phenomena discussed in the theory

Treatment of textiles industrial wastewater by electron beam and biological treatment (sbr)

International Nuclear Information System (INIS)

Khomsaton Abu Bakar; Khairul Zaman Mohd Dahlan; Zulkafli Ghazali; Ting Teo Ming

2008-08-01

Study of treating textiles industrial wastewater with combined of electron beam and Tower Style Biological Treatment (TSB) was investigated in Korea. In this project, textiles wastewater was also treated with electron beam, but hybrid with Sequencing Batch Reactor (SBR). The purpose of this research is to develop combined electron beam treatment with existing biological treatment facility (SBR), of textile industries in Malaysia. The objectives of this project are to determine the effective irradiation parameter for treatment and to identify effective total retention time in SBR system. To achieve the objective, samples fill in polypropyle tray were irradiated at 1 MeV, 20 mA and 1 MeV ,5 mA at doses 11, 20, 30, 40 and 50 kGy respectively. Raw effluent and two series of irradiated effluent at 1 MeV 20 mA (11, 20, 30, 40 and 50 kGy) and 1 MeV 5 mA (11, 20, 30, 40 and 50 kGy) were then treated in SBR system. Samples were analysed at 6, 14 and 20 hrs after aeration in the SBR. The results show that, average reduction in BOD was about 2-11% after irradiated at 5 mA, and the percentage increased to 21-73% after treatment in SBR system. At 20 mA, BOD reduced to 7-29% during irradiation and the value increased to 57-87% after treatment in SBR system. (Author)

Technical Note: Using experimentally determined proton spot scanning timing parameters to accurately model beam delivery time.

Science.gov (United States)

Shen, Jiajian; Tryggestad, Erik; Younkin, James E; Keole, Sameer R; Furutani, Keith M; Kang, Yixiu; Herman, Michael G; Bues, Martin

2017-10-01

To accurately model the beam delivery time (BDT) for a synchrotron-based proton spot scanning system using experimentally determined beam parameters. A model to simulate the proton spot delivery sequences was constructed, and BDT was calculated by summing times for layer switch, spot switch, and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system. These parameters included the layer switch time, magnet preparation and verification time, average beam scanning speeds in x- and y-directions, proton spill rate, and maximum charge and maximum extraction time for each spill. The experimentally determined parameters, as well as the nominal values initially provided by the vendor, served as inputs to the model to predict BDTs for 602 clinical proton beam deliveries. The calculated BDTs (T BDT ) were compared with the BDTs recorded in the treatment delivery log files (T Log ): ∆t = T Log -T BDT . The experimentally determined average layer switch time for all 97 energies was 1.91 s (ranging from 1.9 to 2.0 s for beam energies from 71.3 to 228.8 MeV), average magnet preparation and verification time was 1.93 ms, the average scanning speeds were 5.9 m/s in x-direction and 19.3 m/s in y-direction, the proton spill rate was 8.7 MU/s, and the maximum proton charge available for one acceleration is 2.0 ± 0.4 nC. Some of the measured parameters differed from the nominal values provided by the vendor. The calculated BDTs using experimentally determined parameters matched the recorded BDTs of 602 beam deliveries (∆t = -0.49 ± 1.44 s), which were significantly more accurate than BDTs calculated using nominal timing parameters (∆t = -7.48 ± 6.97 s). An accurate model for BDT prediction was achieved by using the experimentally determined proton beam therapy delivery parameters, which may be useful in modeling the interplay effect and patient throughput. The model may

Acceleration region influence on beam parameters on stripping foil

International Nuclear Information System (INIS)

Samsonov, E.V.; Tomic, S.

1999-01-01

Some formulas describing the beam parameters on the stripping foil (SF) as a function of the radial amplitude of betatron oscillations and energy gain are derived. The results computed by these formulas are in good agreement with the results of the numerical calculations. Obtained results show that between the radial emittance and the energy spread exists parametric dependence via amplitude of radial betatron oscillations. This conclusion allows one to create a working diagram of expected beam parameters on SF. This diagram may be particularly useful for the extraction system designers since it gives relationship between parameters considered as the extraction system input parameters. (author)

Film dosimetry of small elongated electron beams for treatment planning

International Nuclear Information System (INIS)

Niroomand-Rad, A.

1989-01-01

The characteristics of 5, 7, 10, 12, 15, and 18 Mev electron beams for small elongated fields of dimensions L x W (where L=1, 2, 3, 4, 5, and 10 cm; and W=1, 2, 3, 4, 5, and 10 cm) have been studied. Film dosimetry and parallel-plate ion chamber measurements have been used to obtain various dose parameters. Selective results of a series of systematic measurements for central axis depth dose data, uniformity index, field flatness, and relative output factors of small elongated electron beams are reported. The square-root method is employed to predict the beam data of small elongated electron fields from corresponding small square electron fields using film dosimetry. The single parameter area/perimeter radio A/P is used to characterize the relative output factors of elongated electron beams. It is our conclusion that for clinical treatment planning square-root method may be applied with caution in determining the beam characteristics of small elongated electron fields from film dosimetry. The calculated and estimated relative output factors from square-root method and A/P ratio are in good agreement and show agreement to within 1% with the measured film values

Preliminary results with a strip ionization chamber used as beam monitor for hadrontherapy treatments

Energy Technology Data Exchange (ETDEWEB)

Boriano, A. [Dipartimento di Fisica Sperimentale e INFN, Via P.Giuria 1, 1-10125 Turin (Italy); Bourhaleb, F. [Fondazione TERA, Via Puccini 1, 1-28100 Novara (Italy); Cirio, R. [Dipartimento di Fisica Sperimentale e INFN, Via P.Giuria 1, 1-10125 Turin (Italy)] (and others)

2006-01-15

Preliminary results are presented from a test of a parallel plate ionization chamber with the anode segmented in strips (MOPI) to be used as a beam monitor for therapeutical treatments on the 62 MeV proton beam line of the INFN-LNS Superconducting Cyclotron. Ocular pathologies have been treated at the Catana facility since March 2002. The detector, placed downstream of the patient collimator, will allow the measurement of the relevant beam diagnostic parameters during treatment such as integrated beam fluence, for dose determination; the beam baricentre, width and asymmetry will be obtained from the fluence profile sampled with a resolution of about 100 Urn at a rate up to 1 kHz with no dead time. In this test, carried out at LNS, the detector has been exposed to different beam shapes and the integrated fluence derived by the measured beam profiles has been compared with that obtained with other dosimeters normally used for treatment. The skewness of the beam profile has been measured and shown to be suitable to on-line check variations of the beam shape.

Preliminary results with a strip ionization chamber used as beam monitor for hadrontherapy treatments

International Nuclear Information System (INIS)

Boriano, A.; Bourhaleb, F.; Cirio, R.

2006-01-01

Preliminary results are presented from a test of a parallel plate ionization chamber with the anode segmented in strips (MOPI) to be used as a beam monitor for therapeutical treatments on the 62 MeV proton beam line of the INFN-LNS Superconducting Cyclotron. Ocular pathologies have been treated at the Catana facility since March 2002. The detector, placed downstream of the patient collimator, will allow the measurement of the relevant beam diagnostic parameters during treatment such as integrated beam fluence, for dose determination; the beam baricentre, width and asymmetry will be obtained from the fluence profile sampled with a resolution of about 100 Urn at a rate up to 1 kHz with no dead time. In this test, carried out at LNS, the detector has been exposed to different beam shapes and the integrated fluence derived by the measured beam profiles has been compared with that obtained with other dosimeters normally used for treatment. The skewness of the beam profile has been measured and shown to be suitable to on-line check variations of the beam shape

Preliminary results with a strip ionization chamber used as beam monitor for hadrontherapy treatments

Science.gov (United States)

Boriano, A.; Bourhaleb, F.; Cirio, R.; Cirrone, G. A. P.; Cuttone, G.; Donetti, M.; Garelli, E.; Giordanengo, S.; Luparia, A.; Marchette, F.; Peroni, C.; Raffaele, L.; Sabini, M. G.; Valastro, L.

2006-01-01

Preliminary results are presented from a test of a parallel plate ionization chamber with the anode segmented in strips (MOPI) to be used as a beam monitor for therapeutical treatments on the 62 MeV proton beam line of the INFN-LNS Superconducting Cyclotron. Ocular pathologies have been treated at the Catana facility since March 2002. The detector, placed downstream of the patient collimator, will allow the measurement of the relevant beam diagnostic parameters during treatment such as integrated beam fluence, for dose determination; the beam baricentre, width and asymmetry will be obtained from the fluence profile sampled with a resolution of about 100 Urn at a rate up to 1 kHz with no dead time. In this test, carried out at LNS, the detector has been exposed to different beam shapes and the integrated fluence derived by the measured beam profiles has been compared with that obtained with other dosimeters normally used for treatment. The skewness of the beam profile has been measured and shown to be suitable to on-line check variations of the beam shape.

Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation

Science.gov (United States)

Rocha, G.; Pagano, L.; Górski, K. M.; Huffenberger, K. M.; Lawrence, C. R.; Lange, A. E.

2010-04-01

We introduce a new method to propagate uncertainties in the beam shapes used to measure the cosmic microwave background to cosmological parameters determined from those measurements. The method, called markov chain beam randomization (MCBR), randomly samples from a set of templates or functions that describe the beam uncertainties. The method is much faster than direct numerical integration over systematic “nuisance” parameters, and is not restricted to simple, idealized cases as is analytic marginalization. It does not assume the data are normally distributed, and does not require Gaussian priors on the specific systematic uncertainties. We show that MCBR properly accounts for and provides the marginalized errors of the parameters. The method can be generalized and used to propagate any systematic uncertainties for which a set of templates is available. We apply the method to the Planck satellite, and consider future experiments. Beam measurement errors should have a small effect on cosmological parameters as long as the beam fitting is performed after removal of 1/f noise.

Electron beam treatment of industrial wastewater

International Nuclear Information System (INIS)

Han, Bumsoo; Kim, JinKyu; Kim, Yuri

2004-01-01

For industrial wastewater with low impurity levels such as contaminated ground water, cleaning water and etc., purification only with electron beam is possible, but it should be managed carefully with reducing required irradiation doses as low as possible. Also for industrial wastewater with high impurity levels such as dyeing wastewater, leachate and etc., purification only with electron beam requires high amount of doses and far beyond economies. Electron beam treatment combined with conventional purification methods such as coagulation, biological treatment, etc. is suitable for reduction of non-biodegradable impurities in wastewater and will extend the application area of electron beam. A pilot plant with electron beam for treating 1,000 m 3 /day of wastewater from dyeing industries has constructed and operated continuously since Oct 1998. Electron beam irradiation instead of chemical treatment shows much improvement in removing impurities and increases the efficiency of biological treatment. Actual plant is under consideration based upon the experimental results. (author)

Analytical investigation on domain of decentered parameter for self-focusing of Hermite-cosh-Gaussian laser beam in collisional plasma

Science.gov (United States)

Valkunde, Amol T.; Patil, Sandip D.; Vhanmore, Bandopant D.; Urunkar, Trupti U.; Gavade, Kusum M.; Takale, Mansing V.; Fulari, Vijay J.

2018-03-01

In the present paper, an analytically investigated domain of decentered parameter and its effect on the self-focusing of Hermit-cosh-Gaussian (HChG) laser beams in a collisional plasma have been studied theoretically. The nonlinearity in the dielectric constant of plasma arising due to the nonuniform heating of carriers along the wavefront of the laser beam has been employed in the present investigation. The nonlinear differential equation of beam width parameter for various laser modes of HChG beam is obtained by following the standard Akhamanov's parabolic equation approach under Wentzel-Kramers-Brillouin and paraxial approximations. The analytical treatment has enabled us to define three distinct regions: self-focusing, self-trapping and defocusing, which are presented graphically.

Parameters Affecting the Transient Response of an Impacting Beam

Directory of Open Access Journals (Sweden)

Weiping Xu

2013-01-01

Full Text Available Impact causes shock waves that may be unexpected and damaging. A computationally efficient impact model with a generic beam which is discrete in time and continuous in space was undertaken; an Euler-Bernoulli beam with adjustable boundary conditions and variable contact location is numerically studied under a pulse loading. Experiments on a cantilever beam were carried out to verify the effects of influential parameters. A half-sine pulse excitation was applied through a mechanical shaker, and the deflection was captured by a high speed camera. Numerous test cases were conducted that varied pulse duration, pulse amplitude, and clearance. Decreasing the pulse duration lowers all deflection amplitudes, but the time in contact is insensitive. No gap causes minimal beam response, and increasing gap generates greater deflection. Representative test cases were selected for validating the theoretical model. When comparing numerical simulation with experimental results, satisfactory agreement for amplitude and duration can be reached even with raw input parameters. The contribution of this study is the incorporation of unique pulse loading, changeable boundary conditions, adjustable contact/impact situations, comprehensive parameter studies, and high speed photography.

Pertinence analysis of intensity-modulated radiation therapy dosimetry error and parameters of beams

International Nuclear Information System (INIS)

Chi Zifeng; Liu Dan; Cao Yankun; Li Runxiao; Han Chun

2012-01-01

Objective: To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification. Methods: Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria. The plans were copied to water-phantom, 0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose. The statistical data of the parameters of beams for the 43 cases were collected, and the relationships among them were analyzed. The statistical data of the dosimetry error were collected, and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results. Results: The parameters of beams were correlated among each other. Obvious affiliation existed between the dose accuracy and parameter settings. When the beam segment number of IMRT plan was more than 80, the dose deviation would be greater than 3%; however, if the beam segment number was less than 80, the dose deviation was smaller than 3%. When the beam segment number was more than 100, part of the dose deviation of this plan was greater than 4%. On the contrary, if the beam segment number was less than 100, the dose deviation was smaller than 4% definitely. Conclusions: In order to decrease the absolute dose verification error, less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80. (authors)

Kinetic parameter estimation from SPECT cone-beam projection measurements

International Nuclear Information System (INIS)

Huesman, Ronald H.; Reutter, Bryan W.; Zeng, G. Larry; Gullberg, Grant T.

1998-01-01

Kinetic parameters are commonly estimated from dynamically acquired nuclear medicine data by first reconstructing a dynamic sequence of images and subsequently fitting the parameters to time-activity curves generated from regions of interest overlaid upon the image sequence. Biased estimates can result from images reconstructed using inconsistent projections of a time-varying distribution of radiopharmaceutical acquired by a rotating SPECT system. If the SPECT data are acquired using cone-beam collimators wherein the gantry rotates so that the focal point of the collimators always remains in a plane, additional biases can arise from images reconstructed using insufficient, as well as truncated, projection samples. To overcome these problems we have investigated the estimation of kinetic parameters directly from SPECT cone-beam projection data by modelling the data acquisition process. To accomplish this it was necessary to parametrize the spatial and temporal distribution of the radiopharmaceutical within the SPECT field of view. In a simulated chest image volume, kinetic parameters were estimated for simple one-compartment models for four myocardial regions of interest. Myocardial uptake and washout parameters estimated by conventional analysis of noiseless simulated cone-beam data had biases ranging between 3-26% and 0-28%, respectively. Parameters estimated directly from the noiseless projection data were unbiased as expected, since the model used for fitting was faithful to the simulation. Statistical uncertainties of parameter estimates for 10 000 000 events ranged between 0.2-9% for the uptake parameters and between 0.3-6% for the washout parameters. (author)

Vibrations And Stability Of Bernoulli-Euler And Timoshenko Beams On Two-Parameter Elastic Foundation

Directory of Open Access Journals (Sweden)

Obara P.

2014-12-01

Full Text Available The vibration and stability analysis of uniform beams supported on two-parameter elastic foundation are performed. The second foundation parameter is a function of the total rotation of the beam. The effects of axial force, foundation stiffness parameters, transverse shear deformation and rotatory inertia are incorporated into the accurate vibration analysis. The work shows very important question of relationships between the parameters describing the beam vibration, the compressive force and the foundation parameters. For the free supported beam, the exact formulas for the natural vibration frequencies, the critical forces and the formula defining the relationship between the vibration frequency and the compressive forces are derived. For other conditions of the beam support conditional equations were received. These equations determine the dependence of the frequency of vibration of the compressive force for the assumed parameters of elastic foundation and the slenderness of the beam.

Surface treatment by the ion flow from electron beam generated plasma in the forevacuum pressure range

Directory of Open Access Journals (Sweden)

Klimov Aleksandr

2018-01-01

Full Text Available The paper presents research results of peculiarities of gas ion flows usage and their generation from large plasma formation (>50 sq.cm obtained by electron beam ionization of gas in the forevacuum pressure range. An upgraded source was used for electron beam generation, which allowed obtaining ribbon electron beam with no transmitting magnetic field. Absence of magnetic field in the area of ion flow formation enables to obtain directed ion flows without distorting their trajectories. In this case, independent control of current and ion energy is possible. The influence of electron beam parameters on the parameters of beam plasma and ion flow – current energy and density – was determined. The results of alumina ceramics treatment with a beam plasma ions flow are given.

Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators

Directory of Open Access Journals (Sweden)

C. S. Edmonds

2014-05-01

Full Text Available In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA.

Beam parameter measurements for the SLAC linear collider

International Nuclear Information System (INIS)

Clendenin, J.E.; Blocker, C.; Breidenbach, M.

1982-01-01

A stable, closely-controlled, high-intensity, single-bunch beam will be required for the SLAC Linear Collider. The characteristics of short-pulse, low-intensity beams in the SLAC linac have been studied. A new, high-intensity thermionic gun, subharmonic buncher and S-band buncher/accelerator section were installed recently at SLAC. With these components, up to 10 11 electrons in a single S-band bunch are available for injection into the linac. the first 100-m accelerator sector has been modified to allow control of short-pulse beams by a model-driven computer program. Additional instrumentation, including a computerized energy analyzer and emittance monitor have been added at the end of the 100-m sector. The beam intensity, energy spectrum, emittance, charge distribution and the effect of wake fields in the first accelerator sector have been measured. The new source and beam control system will be described and the most recent results of the beam parameter measurements will be discussed

Electron-beam flue-gas treatment system

International Nuclear Information System (INIS)

Aoki, Sinji; Suzuki, Ryoji

1994-01-01

The damage of forests in the world due to acid rain has become serious problems, and the development of high efficiency and economical desulfurization and denitration technologies for combustion exhaust gas has been desired. Japan leads the world in exhaust gas treatment technology. The conventional technologies have been the desulfurization by lime gypsum process and the denitration by ammonia catalytic reduction process. The solution by entirely new concept is the electron beam treatment technology for exhaust gas. This technology is a dry process without drain, and does not require catalyst. The byproduct from this technology was approved as a fertilizer. The electron beam treatment technology is called EBA (electron beam with ammonia). The exhaust gas treatment technology by electron beam process is constituted by the cooling of exhaust gas, ammonia addition, electron beam irradiation and the separation of byproduct. The features of the technology are the simultaneous removal of sulfur and nitrogen oxides, dry process, the facilities are simple and the operation is easy, easy following to load variation and the utilization of byproduct. The reaction mechanism of desulfurization and denitration, the course of development, the electron beam generator, and the verifying test are reported. (K.I.)

Crack classification in concrete beams using AE parameters

Science.gov (United States)

Bahari, N. A. A. S.; Shahidan, S.; Abdullah, S. R.; Ali, N.; Zuki, S. S. Mohd; Ibrahim, M. H. W.; Rahim, M. A.

2017-11-01

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm × 250 mm × 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

MO-H-19A-01: FEATURED PRESENTATION - Treatment Planning Tool for Radiotherapy with Very High-Energy Electron Beams

International Nuclear Information System (INIS)

Bazalova, M; Qu, B; Palma, B; Loo, B; Maxim, P; Hynning, E; Hardemark, B

2014-01-01

Purpose: To develop a tool for treatment planning optimization for fast radiotherapy delivered with very high-energy electron beams (VHEE) and to compare VHEE plans to state-of-the-art plans for challenging pelvis and H'N cases. Methods: Treatment planning for radiotherapy delivered with VHEE scanning pencil beams was performed by integrating EGSnrc Monte Carlo (MC) dose calculations with spot scanning optimization run in a research version of RayStation. A Matlab GUI for MC beamlet generation was developed, in which treatment parameters such as the pencil beam size and spacing, energy and number of beams can be selected. Treatment planning study for H'N and pelvis cases was performed and the effect of treatment parameters on the delivered dose distributions was evaluated and compared to the clinical treatment plans. The pelvis case with a 691cm3 PTV was treated with 2-arc 15MV VMAT and the H'N case with four PTVs with total volume of 531cm3 was treated with 4-arc 6MV VMAT. Results: Most studied VHEE plans outperformed VMAT plans. The best pelvis 80MeV VHEE plan with 25 beams resulted in 12% body dose sparing and 8% sparing to the bowel and right femur compared to the VMAT plan. The 100MeV plan was superior to the 150MeV plan. Mixing 100 and 150MeV improved dose sparing to the bladder by 7% compared to either plan. Plans with 16 and 36 beams did not significantly affect the dose distributions compared to 25 beam plans. The best H'N 100MeV VHEE plan decreased mean doses to the brainstem, chiasm, and both globes by 10-42% compared to the VMAT plan. Conclusion: The pelvis and H'N cases suggested that sixteen 100MeV beams might be sufficient specifications of a novel VHEE treatment machine. However, optimum machine parameters will be determined with the presented VHEE treatment-planning tool for a large number of clinical cases. BW Loo and P Maxim received research support from RaySearch Laboratories. E Hynning and B Hardemark are employees of

Determination of electron beam parameters by means of laser-Compton scattering

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K. Chouffani

2006-05-01

Full Text Available Laser-Compton scattering (LCS experiments were carried out at the Idaho Accelerator Center using the 5 ns (FWHM and 22 MeV electron beam. The electron beam was brought to an approximate head-on collision with a 29 MW, 7 ns (FWHM, 10 Hz Nd:YAG laser. Clear and narrow x-ray peaks resulting from the interaction of relativistic electrons with the Nd:YAG laser second harmonic line at 532 nm were observed. We have developed a relatively new method of using LCS as a nonintercepting electron beam monitor. Our method focused on the variation of the shape of the LCS spectrum rather than the LCS intensity as a function of the observation angle in order to extract the electron beam parameters at the interaction region. The electron beam parameters were determined by making simultaneous fits to spectra taken across the LCS x-ray cone. This scan method allowed us also to determine the variation of LCS x-ray peak energies and spectral widths as a function of the detector angles. Experimental data show that in addition to being viewed as a potential bright, tunable, and quasimonochromatic x-ray source, LCS can provide important information on the electron beam pulse length, direction, energy, angular and energy spread. Since the quality of LCS x-ray peaks, such as degree of monochromaticity, peak energy and flux, depends strongly on the electron beam parameters, LCS can therefore be viewed as an important nondestructive tool for electron beam diagnostics.

An analysis of beam parameters on proton-acoustic waves through an analytic approach.

Science.gov (United States)

Kipergil, Esra Aytac; Erkol, Hakan; Kaya, Serhat; Gulsen, Gultekin; Unlu, Mehmet Burcin

2017-06-21

It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution for the proton-induced acoustic wave is presented to reveal the dependence of the signal on the beam parameters; then it is combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of the proton-acoustic signals. Our results show that the smaller spill time of the proton beam upsurges the amplitude of the acoustic wave for a constant number of protons, which is hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to the spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.

Thermo-mechanical simulation and parameters optimization for beam blank continuous casting

International Nuclear Information System (INIS)

Chen, W.; Zhang, Y.Z.; Zhang, C.J.; Zhu, L.G.; Lu, W.G.; Wang, B.X.; Ma, J.H.

2009-01-01

The objective of this work is to optimize the process parameters of beam blank continuous casting in order to ensure high quality and productivity. A transient thermo-mechanical finite element model is developed to compute the temperature and stress profile in beam blank continuous casting. By comparing the calculated data with the metallurgical constraints, the key factors causing defects of beam blank can be found out. Then based on the subproblem approximation method, an optimization program is developed to search out the optimum cooling parameters. Those optimum parameters can make it possible to run the caster at its maximum productivity, minimum cost and to reduce the defects. Now, online verifying of this optimization project has been put in practice, which can prove that it is very useful to control the actual production

Influence of ion beam and geometrical parameters on properties of Si thin films grown by Ar ion beam sputtering

Energy Technology Data Exchange (ETDEWEB)

Bundesmann, Carsten; Feder, Rene; Neumann, Horst [Leibniz-Institut fuer Oberflaechenmodifizierung e.V., Leipzig (Germany)

2012-07-01

Ion beam sputtering (IBS) offers, in contrast to other physical vapour deposition techniques, such as magnetron sputtering or electron beam evaporation, the opportunity to change the properties of the layer forming particles (sputtered and scattered particles) by varying ion beam parameters (ion species, ion energy) and geometrical parameters (ion incidence angle, emission angle). Consequently, these effects can be utilized to tailor thin film properties [1]. The goal is to study systematically the correlations between the primary and secondary parameters and, at last, the effects on the properties of Si thin films, such as optical properties, stress, surface topography and composition. First experimental results are presented for Ar-ion sputtering of Si.

Determination of charged particle beam parameters with taking into account of space charge

International Nuclear Information System (INIS)

Ishkhanov, B.S.; Poseryaev, A.V.; Shvedunov, V.I.

2005-01-01

One describes a procedure to determine the basic parameters of a paraxial axially-symmetric beam of charged particles taking account of space charge contribution. The described procedure is based on application of the general equation for beam envelope. Paper presents data on its convergence and resistance to measurement errors. The position determination error of crossover (stretching) and radius of beam in crossover is maximum 15% , while the emittance determination error depends on emittance and space charge correlation. The introduced procedure was used to determine parameters of the available electron gun 20 keV energy beam with 0.64 A current. The derived results turned to agree closely with the design parameters [ru

Dosimetric comparison of single-beam multi-arc and 2-beam multi-arc VMAT optimization in the Monaco treatment planning system

Energy Technology Data Exchange (ETDEWEB)

Kalet, Alan M., E-mail: amkalet@uw.edu [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States); Richardson, Hannah L.; Nikolaisen, Darrin A. [Seattle Cancer Care Alliance, Seattle, Washington (United States); Cao, Ning [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States); Lavilla, Myra A. [Seattle Cancer Care Alliance, Seattle, Washington (United States); Dempsey, Claire; Meyer, Juergen; Koh, Wui-Jin; Russell, Kenneth J. [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Seattle Cancer Care Alliance, Seattle, Washington (United States)

2017-07-01

The purpose of this study was to evaluate the dosimetric and practical effects of the Monaco treatment planning system “max arcs-per-beam” optimization parameter in pelvic radiotherapy treatments. We selected for this study a total of 17 previously treated patients with a range of pelvic disease sites including prostate (9), bladder (1), uterus (3), rectum (3), and cervix (1). For each patient, 2 plans were generated, one using an arc-per-beam setting of “1” and another with an arc-per-beam setting of “2” using the volumes and constraints established from the initial clinical treatments. All constraints and dose coverage objects were kept the same between plans, and all plans were normalized to 99.7% to ensure 100% of the planning target volume (PTV) received 95% of the prescription dose. Plans were evaluated for PTV conformity, homogeneity, number of monitor units, number of control points, and overall plan acceptability. Treatment delivery time, patient-specific quality assurance procedures, and the impact on clinical workflow were also assessed. We found that for complex-shaped target volumes (small central volumes with extending arms to cover nodal regions), the use of 2 arc-per-beam (2APB) parameter setting achieved significantly lower average dose-volume histogram values for the rectum V{sub 20} (p = 0.0012) and bladder V{sub 30} (p = 0.0036) while meeting the high dose target constraints. For simple PTV shapes, we found reduced monitor units (13.47%, p = 0.0009) and control points (8.77%, p = 0.0004) using 2APB planning. In addition, we found a beam delivery time reduction of approximately 25%. In summary, the dosimetric benefit, although moderate, was improved over a 1APB setting for complex PTV, and equivalent in other cases. The overall reduced delivery time suggests that the use of mulitple arcs per beam could lead to reduced patient-on-table time, increased clinical throughput, and reduced medical physics quality assurance

SU-F-J-54: Towards Real-Time Volumetric Imaging Using the Treatment Beam and KV Beam

Energy Technology Data Exchange (ETDEWEB)

Chen, M; Rozario, T; Liu, A; Jiang, S; Lu, W [UT Southwestern Medical Center, Dallas, TX (United States)

2016-06-15

Purpose: Existing real-time imaging uses dual (orthogonal) kV beam fluoroscopies and may result in significant amount of extra radiation to patients, especially for prolonged treatment cases. In addition, kV projections only provide 2D information, which is insufficient for in vivo dose reconstruction. We propose real-time volumetric imaging using prior knowledge of pre-treatment 4D images and real-time 2D transit data of treatment beam and kV beam. Methods: The pre-treatment multi-snapshot volumetric images are used to simulate 2D projections of both the treatment beam and kV beam, respectively, for each treatment field defined by the control point. During radiation delivery, the transit signals acquired by the electronic portal image device (EPID) are processed for every projection and compared with pre-calculation by cross-correlation for phase matching and thus 3D snapshot identification or real-time volumetric imaging. The data processing involves taking logarithmic ratios of EPID signals with respect to the air scan to reduce modeling uncertainties in head scatter fluence and EPID response. Simulated 2D projections are also used to pre-calculate confidence levels in phase matching. Treatment beam projections that have a low confidence level either in pre-calculation or real-time acquisition will trigger kV beams so that complementary information can be exploited. In case both the treatment beam and kV beam return low confidence in phase matching, a predicted phase based on linear regression will be generated. Results: Simulation studies indicated treatment beams provide sufficient confidence in phase matching for most cases. At times of low confidence from treatment beams, kV imaging provides sufficient confidence in phase matching due to its complementary configuration. Conclusion: The proposed real-time volumetric imaging utilizes the treatment beam and triggers kV beams for complementary information when the treatment beam along does not provide sufficient

Beam-beam force and storage ring parameters

International Nuclear Information System (INIS)

Herrera, J.C.

1979-01-01

The fundamental aspects of the beam--beam force as it occurs in Intersecting Storage Rings are reported. The way in which the effect of the beam--particle electromagnetic force (weak--strong interaction) is different in the case of unbunched proton beams which cross each other at an angle (as in the ISR and in ISABELLE) is shown, as compared to the case of electron--positron beams where bunches collide head-on

Beta Beams for Precision Measurements of Neutrino Oscillation Parameters

CERN Document Server

Wildner, E; Hansen, C; De Melo Mendonca, T; Stora, T; Damjanovic, S; Payet, J; Chancé, A; Zorin, V; Izotov, I; Rasin, S; Sidorov, A; Skalyga, V; De Angelis, G; Prete, G; Cinausero, M; Kravchuk, V; Gramegna, F; Marchi, T; Collazuol, G; Mezzetto, M; Delbar, T; Loiselet, M; Keutgen, T; Mitrofanov, S; Burt, G; Dexter, A; Lamy, T; Latrasse, L; Marie-Jeanne, M; Sortais, P; Thuillier, T; Debray, F; Trophime, C; Hass, M; Hirsh, T; Berkovits, D; Stahl, A; Vardaci, E; Di Nitto, A; Brondi, A; La Rana, G; Moro, R; De Rosa, G; Palladino, V

2012-01-01

Neutrino oscillations have implications for the Standard Model of particle physics. The CERN Beta Beam has outstanding capabilities to contribute to precision measurements of the parameters governing neutrino oscillations. The FP7 collaboration EUROnu (2008-2012) is a design study that will review three facilities (Super-Beams, Beta Beams and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make decisions on future European neutrino oscillation facilities. ”Beta Beams” produce collimated pure electron (anti)neutrinos by accelerating beta active ions to high energies and having them decay in a storage ring. Using existing machines and infrastructure is an advantage for the cost evaluation; however, this choice is also constraining the Beta Beams. Recent work to make the Beta Beam facility a solid option will be described: production of Beta Beam isotopes, the 60 GHz pulsed ECR source development, integratio...

Note: Characteristic beam parameter for the line electron gun

Science.gov (United States)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm2), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Note: Characteristic beam parameter for the line electron gun

International Nuclear Information System (INIS)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-01-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm 2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm 2 ), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful

Note: Characteristic beam parameter for the line electron gun.

Science.gov (United States)

Iqbal, M; Islam, G U; Zhou, Z; Chi, Y

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Measurement of proton-beam parameters by means of digital television diagnostic system

International Nuclear Information System (INIS)

Vazhenin, V.A.; Borovkov, S.D.; Evtikhiev, A.V.

1992-01-01

A method is described for measurement of the parameters of pulse-packet beams by means of a digital television diagnostic system. Results of tests of the system in measurement of the parameters of a proton beam with an energy of 1.35 GeV in the U-70 circular accelerator and results of measurements of the energy spectrum of the 30-MeV proton beam of the LU-30 linear accelerator are given. The possibility is shown of using the system to measure the integrated characteristics of an entire beam-pulse packet as well as the characteristics of individual pulses with a period of 60 msec. 6 refs., 4 figs., 1 tab

Optimization of parameters for fitting linear accelerator photon beams using a modified CBEAM model

International Nuclear Information System (INIS)

Ayyangar, K.; Daftari, I.; Palta, J.; Suntharalingam, N.

1989-01-01

Measured beam profiles and central-axis depth-dose data for 6- and 25-MV photon beams are used to generate a dose matrix which represents the full beam. A corresponding dose matrix is also calculated using the modified CBEAM model. The calculational model uses the usual set of three parameters to define the intensity at beam edges and the parameter that accounts for collimator transmission. An additional set of three parameters is used for the primary profile factor, expressed as a function of distance from the central axis. An optimization program has been adapted to automatically adjust these parameters to minimize the χ 2 between the measured and calculated data. The average values of the parameters for small (6x6 cm 2 ), medium (10x10 cm 2 ), and large (20x20 cm 2 ) field sizes are found to represent the beam adequately for all field sizes. The calculated and the measured doses at any point agree to within 2% for any field size in the range 4x4 to 40x40 cm 2

Scintillator-CCD camera system light output response to dosimetry parameters for proton beam range measurement

Energy Technology Data Exchange (ETDEWEB)

Daftari, Inder K., E-mail: idaftari@radonc.ucsf.edu [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States); Castaneda, Carlos M.; Essert, Timothy [Crocker Nuclear Laboratory,1 Shields Avenue, University of California-Davis, Davis, CA 95616 (United States); Phillips, Theodore L.; Mishra, Kavita K. [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States)

2012-09-11

and good agreement was observed. The peak/plateau ratio observed for the scintillator was found to be 2.21 as compared to the ionization chamber measurements of 3.01. The response of a scintillator block-CCD camera in 67.5 MeV proton beam was investigated. A linear response was seen between light output and beam current as well as aperture size. The relation between the thickness of water in the water column and the measured range also showed linearity. The results from the scintillator response was used to develop a simple approach to measuring the range and the Bragg peak of a proton beam by recording the visible light from a scintillator block with an accuracy of less than 0.33 mm. Optimal dosimetry parameters for our proton beam were evaluated. It is observed that this method can be used to confirm the range of a proton beam during daily treatment and will be useful as daily QA measurement for proton beam therapy.

Exposure parameters in proton beam writing for hydrogen silsesquioxane

International Nuclear Information System (INIS)

Kan, J.A. van; Zhang, F.; Zhang, C.; Bettiol, A.A.; Watt, F.

2008-01-01

In proton beam writing (PBW) a focused MeV proton beam is scanned in a predetermined pattern over a resist (e.g. PMMA, SU-8 or HSQ), which is subsequently chemically developed. In e-beam writing as well as p-beam writing the energy loss of the primary beam is dominated by energy transfer to substrate electrons. Unlike the high energy secondary electrons generated during e-beam writing the secondary electrons induced by the primary proton beam have low energy and therefore a limited range, resulting in minimal proximity effects. The low proximity effects exhibited by p-beam writing coupled with the straight trajectory and high penetration of the proton beam enables the production of high aspect ratio, high density 3D micro and nanostructures with well defined smooth side walls to be directly written into resist materials. This property together with the stability and focusing power of the end station ensures even exposures with nm smoothness and allows fabrication of details down to the 20 nm level. In this paper, we present results like contrast and sensitivity for PBW using, hydrogen silsesquioxane (HSQ) and XR-1541, both are non-C based resists. Unlike PMMA and SU-8 resist HSQ shows aging effects, requiring optimized processing parameters in PBW

Note: Characteristic beam parameter for the line electron gun

Energy Technology Data Exchange (ETDEWEB)

Iqbal, M. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z.; Chi, Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2013-11-15

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

TU-FG-201-03: Automatic Pre-Delivery Verification Using Statistical Analysis of Consistencies in Treatment Plan Parameters by the Treatment Site and Modality

International Nuclear Information System (INIS)

Liu, S; Wu, Y; Chang, X; Li, H; Yang, D

2016-01-01

Purpose: A novel computer software system, namely APDV (Automatic Pre-Delivery Verification), has been developed for verifying patient treatment plan parameters right prior to treatment deliveries in order to automatically detect and prevent catastrophic errors. Methods: APDV is designed to continuously monitor new DICOM plan files on the TMS computer at the treatment console. When new plans to be delivered are detected, APDV checks the consistencies of plan parameters and high-level plan statistics using underlying rules and statistical properties based on given treatment site, technique and modality. These rules were quantitatively derived by retrospectively analyzing all the EBRT treatment plans of the past 8 years at authors’ institution. Therapists and physicists will be notified with a warning message displayed on the TMS computer if any critical errors are detected, and check results, confirmation, together with dismissal actions will be saved into database for further review. Results: APDV was implemented as a stand-alone program using C# to ensure required real time performance. Mean values and standard deviations were quantitatively derived for various plan parameters including MLC usage, MU/cGy radio, beam SSD, beam weighting, and the beam gantry angles (only for lateral targets) per treatment site, technique and modality. 2D-based rules of combined MU/cGy ratio and averaged SSD values were also derived using joint probabilities of confidence error ellipses. The statistics of these major treatment plan parameters quantitatively evaluate the consistency of any treatment plans which facilitates automatic APDV checking procedures. Conclusion: APDV could be useful in detecting and preventing catastrophic errors immediately before treatment deliveries. Future plan including automatic patient identify and patient setup checks after patient daily images are acquired by the machine and become available on the TMS computer. This project is supported by the

TU-FG-201-03: Automatic Pre-Delivery Verification Using Statistical Analysis of Consistencies in Treatment Plan Parameters by the Treatment Site and Modality

Energy Technology Data Exchange (ETDEWEB)

Liu, S; Wu, Y; Chang, X; Li, H; Yang, D [Washington University School of Medicine, St. Louis, MO (United States)

2016-06-15

Purpose: A novel computer software system, namely APDV (Automatic Pre-Delivery Verification), has been developed for verifying patient treatment plan parameters right prior to treatment deliveries in order to automatically detect and prevent catastrophic errors. Methods: APDV is designed to continuously monitor new DICOM plan files on the TMS computer at the treatment console. When new plans to be delivered are detected, APDV checks the consistencies of plan parameters and high-level plan statistics using underlying rules and statistical properties based on given treatment site, technique and modality. These rules were quantitatively derived by retrospectively analyzing all the EBRT treatment plans of the past 8 years at authors’ institution. Therapists and physicists will be notified with a warning message displayed on the TMS computer if any critical errors are detected, and check results, confirmation, together with dismissal actions will be saved into database for further review. Results: APDV was implemented as a stand-alone program using C# to ensure required real time performance. Mean values and standard deviations were quantitatively derived for various plan parameters including MLC usage, MU/cGy radio, beam SSD, beam weighting, and the beam gantry angles (only for lateral targets) per treatment site, technique and modality. 2D-based rules of combined MU/cGy ratio and averaged SSD values were also derived using joint probabilities of confidence error ellipses. The statistics of these major treatment plan parameters quantitatively evaluate the consistency of any treatment plans which facilitates automatic APDV checking procedures. Conclusion: APDV could be useful in detecting and preventing catastrophic errors immediately before treatment deliveries. Future plan including automatic patient identify and patient setup checks after patient daily images are acquired by the machine and become available on the TMS computer. This project is supported by the

Modeling of ion beam surface treatment

Energy Technology Data Exchange (ETDEWEB)

Stinnett, R W [Quantum Manufacturing Technologies, Inc., Albuquerque, NM (United States); Maenchen, J E; Renk, T J [Sandia National Laboratories, Albuquerque, NM (United States); Struve, K W [Mission Research Corporation, Albuquerque, NM (United States); Campbell, M M [PASTDCO, Albuquerque, NM (United States)

1997-12-31

The use of intense pulsed ion beams is providing a new capability for surface engineering based on rapid thermal processing of the top few microns of metal, ceramic, and glass surfaces. The Ion Beam Surface Treatment (IBEST) process has been shown to produce enhancements in the hardness, corrosion, wear, and fatigue properties of surfaces by rapid melt and re-solidification. A new code called IBMOD was created, enabling the modeling of intense ion beam deposition and the resulting rapid thermal cycling of surfaces. This code was used to model the effect of treatment of aluminum, iron, and titanium using different ion species and pulse durations. (author). 3 figs., 4 refs.

Application of electron beam irradiation. 4. Treatment of pollutants by electron beam irradiation

International Nuclear Information System (INIS)

Tokunaga, Okihiro; Arai, Hidehiko

1994-01-01

Electron beam irradiation is capable of dissolving and removing pollutants, such as sulfur oxides, nitrogen oxides, and organic compounds, by easy production of OH radicals in flue gas and water. This paper deals with current status in the search for techniques for treating flue gas and waste water, using electron beam irradiation. Pilot tests have been conducted during the period 1991-1994 for the treatment of flue gas caused by coal and garbage burning and road tunnels. Firstly, techniques for cleaning flue gas with electron beams are outlined, with special reference to their characteristics and process of research development. Secondly, the application of electron beam irradiation in the treatment of waste water is described in terms of the following: (1) disinfection of sewage, (2) cleaning of water polluted with toxic organic compounds, (3) treatment for eliminating sewage sludge, (4) promotion of sewage sludge sedimentation, (5) disinfection and composting of sewage sludge, and (6) regeneration of activated carbon used for the treatment of waste water. (N.K.)

Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy

International Nuclear Information System (INIS)

Fogliata, A.; Garcia, R.; Knöös, T.; Nicolini, G.; Clivio, A.; Vanetti, E.; Khamphan, C.; Cozzi, L.

2012-01-01

Purpose: Flattening filter free (FFF) beams generated by medical linear accelerators have recently started to be used in radiotherapy clinical practice. Such beams present fundamental differences with respect to the standard filter flattened (FF) beams, making the generally used dosimetric parameters and definitions not always viable. The present study will propose possible definitions and suggestions for some dosimetric parameters for use in quality assurance of FFF beams generated by medical linacs in radiotherapy. Methods: The main characteristics of the photon beams have been analyzed using specific data generated by a Varian TrueBeam linac having both FFF and FF beams of 6 and 10 MV energy, respectively. Results: Definitions for dose profile parameters are suggested starting from the renormalization of the FFF with respect to the corresponding FF beam. From this point the flatness concept has been translated into one of “unflatness” and other definitions have been proposed, maintaining a strict parallelism between FFF and FF parameter concepts. Conclusions: Ideas for quality controls used in establishing a quality assurance program when introducing FFF beams into the clinical environment are given here, keeping them similar to those used for standard FF beams. By following the suggestions in this report, the authors foresee that the introduction of FFF beams into a clinical radiotherapy environment will be as safe and well controlled as standard beam modalities using the existing guidelines.

Pre Design of Beam Parameter Control System for Electron Beam Machine (EBM) 350 keV/10 mA in the Center for Accelerator and Material Process Technology - BATAN Yogyakarta

International Nuclear Information System (INIS)

Sutanto

2009-01-01

Pre design of beam parameter control system for Electron Beam Machine (EBM) 350 keV/10 mA had an objective to find a control system algorithm for EBM in The Center For Accelerator and Material Process Technology (Pusat Teknologi dan Proses Bahan/PTAPB) - BATAN Yogyakarta. The design was based on the beam parameter model of EBM. The model shown a relationship between the dose parameter setting and the beam energy setting which it was being a problem in setting the beam parameters.The control system algorithm was found by getting compensator equations from the beam parameter model of EBM. The equations would omit the relation between the radiation dose parameter and beam energy parameter, so that the parameters could be adjusted easily. The result of the control system algorithm examine based on simulation shown that the setting of beam parameter value could be done by giving the accelerating voltage value and the filament current value as the operator had determined the value. The value of radiation dose and beam energy would be adjusted as its function of the filament current value and the accelerating voltage value. (author)

Hartmann-Shack wave front measurements for real time determination of laser beam propagation parameters

International Nuclear Information System (INIS)

Schaefer, B.; Luebbecke, M.; Mann, K.

2006-01-01

The suitability of the Hartmann-Shack technique for the determination of the propagation parameters of a laser beam is faced against the well known caustic approach according to the ISO 11146 standard. A He-Ne laser (543 nm) was chosen as test beam, both in its fundamental mode as well as after intentional distortion, introducing a moderate amount of spherical aberration. Results are given for the most important beam parameters M 2 , divergence, and beam widths, indicating an agreement of better than 10% and for adapted beam diameter <5%. Furthermore, the theoretical background, pros and cons, as well as some features of the software implementation for the Hartmann-Shack sensor are briefly reviewed

SU-E-T-295: Simultaneous Beam Sampling and Aperture Shape Optimization for Station Parameter Optimized Radiation Therapy (SPORT)

Energy Technology Data Exchange (ETDEWEB)

Zarepisheh, M; Li, R; Xing, L [Stanford UniversitySchool of Medicine, Stanford, CA (United States); Ye, Y [Stanford Univ, Management Science and Engineering, Stanford, Ca (United States); Boyd, S [Stanford University, Electrical Engineering, Stanford, CA (United States)

2014-06-01

Purpose: Station Parameter Optimized Radiation Therapy (SPORT) was recently proposed to fully utilize the technical capability of emerging digital LINACs, in which the station parameters of a delivery system, (such as aperture shape and weight, couch position/angle, gantry/collimator angle) are optimized altogether. SPORT promises to deliver unprecedented radiation dose distributions efficiently, yet there does not exist any optimization algorithm to implement it. The purpose of this work is to propose an optimization algorithm to simultaneously optimize the beam sampling and aperture shapes. Methods: We build a mathematical model whose variables are beam angles (including non-coplanar and/or even nonisocentric beams) and aperture shapes. To solve the resulting large scale optimization problem, we devise an exact, convergent and fast optimization algorithm by integrating three advanced optimization techniques named column generation, gradient method, and pattern search. Column generation is used to find a good set of aperture shapes as an initial solution by adding apertures sequentially. Then we apply the gradient method to iteratively improve the current solution by reshaping the aperture shapes and updating the beam angles toward the gradient. Algorithm continues by pattern search method to explore the part of the search space that cannot be reached by the gradient method. Results: The proposed technique is applied to a series of patient cases and significantly improves the plan quality. In a head-and-neck case, for example, the left parotid gland mean-dose, brainstem max-dose, spinal cord max-dose, and mandible mean-dose are reduced by 10%, 7%, 24% and 12% respectively, compared to the conventional VMAT plan while maintaining the same PTV coverage. Conclusion: Combined use of column generation, gradient search and pattern search algorithms provide an effective way to optimize simultaneously the large collection of station parameters and significantly improves

SU-E-T-295: Simultaneous Beam Sampling and Aperture Shape Optimization for Station Parameter Optimized Radiation Therapy (SPORT)

International Nuclear Information System (INIS)

Zarepisheh, M; Li, R; Xing, L; Ye, Y; Boyd, S

2014-01-01

Purpose: Station Parameter Optimized Radiation Therapy (SPORT) was recently proposed to fully utilize the technical capability of emerging digital LINACs, in which the station parameters of a delivery system, (such as aperture shape and weight, couch position/angle, gantry/collimator angle) are optimized altogether. SPORT promises to deliver unprecedented radiation dose distributions efficiently, yet there does not exist any optimization algorithm to implement it. The purpose of this work is to propose an optimization algorithm to simultaneously optimize the beam sampling and aperture shapes. Methods: We build a mathematical model whose variables are beam angles (including non-coplanar and/or even nonisocentric beams) and aperture shapes. To solve the resulting large scale optimization problem, we devise an exact, convergent and fast optimization algorithm by integrating three advanced optimization techniques named column generation, gradient method, and pattern search. Column generation is used to find a good set of aperture shapes as an initial solution by adding apertures sequentially. Then we apply the gradient method to iteratively improve the current solution by reshaping the aperture shapes and updating the beam angles toward the gradient. Algorithm continues by pattern search method to explore the part of the search space that cannot be reached by the gradient method. Results: The proposed technique is applied to a series of patient cases and significantly improves the plan quality. In a head-and-neck case, for example, the left parotid gland mean-dose, brainstem max-dose, spinal cord max-dose, and mandible mean-dose are reduced by 10%, 7%, 24% and 12% respectively, compared to the conventional VMAT plan while maintaining the same PTV coverage. Conclusion: Combined use of column generation, gradient search and pattern search algorithms provide an effective way to optimize simultaneously the large collection of station parameters and significantly improves

SU-F-T-225: Is It Time to Have Pre-Configured Therapeutic Beams Available in Commercial Treatment Planning Systems?

International Nuclear Information System (INIS)

Ding, G

2016-01-01

Purpose: Commissioning radiation beams requires considerable effort to obtain the beam data for beam configuration in a commercial treatment planning system. With the advances in technology, the manufacturer of accelerators now has the ability to adjust radiation beam parameters to meet pre-determined specifications with high precision. This study aims to illustrate the feasibility of making pre-configured radiation beams available in commercial treatment planning systems. Methods: In recent years, Varian has made a set of measured beam data from the TrueBeam accelerator available to users. Although the beam data are provided as “suggestive data” without warranty, the commissioned data measured by users have been shown to be in excellent agreement with the data set provided when the beams from the installed Linacs were adjusted to meet the beam specifications. An unofficial survey among Varian Linac TrueBeam users shows that the suggestive data set has been used with validation by users in some clinics. This indicates that radiation beams from a specified Linac can be standardized and pre-configured in a treatment planning system. Results: Two newly installed Varian TrueBeam accelerators at two different centers were examined in which one set of commissioned beam data was obtained from measurements performed by an independent physics consulting company and the other was measured by local physicists in the department. All beams from both accelerators were tuned to meet the manufacturer’s specifications. Discrepancies of less than 1% were found between the commissioned beam data from both accelerators and the suggestive data set provided by Varian. Conclusion: It may be feasible that radiation beams can be pre-configured in commercial treatment planning systems. The radiation beam users will perform the beam validation and end-to-end tests instead of configuring beams. This framework can increase both the efficiency and the accuracy in commercial radiation

Constrained treatment planning using sequential beam selection

International Nuclear Information System (INIS)

Woudstra, E.; Storchi, P.R.M.

2000-01-01

In this paper an algorithm is described for automated treatment plan generation. The algorithm aims at delivery of the prescribed dose to the target volume without violation of constraints for target, organs at risk and the surrounding normal tissue. Pre-calculated dose distributions for all candidate orientations are used as input. Treatment beams are selected in a sequential way. A score function designed for beam selection is used for the simultaneous selection of beam orientations and weights. In order to determine the optimum choice for the orientation and the corresponding weight of each new beam, the score function is first redefined to account for the dose distribution of the previously selected beams. Addition of more beams to the plan is stopped when the target dose is reached or when no additional dose can be delivered without violating a constraint. In the latter case the score function is modified by importance factor changes to enforce better sparing of the organ with the limiting constraint and the algorithm is run again. (author)

Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans

International Nuclear Information System (INIS)

Bazalova-Carter, Magdalena; Qu, Bradley; Palma, Bianey; Jensen, Christopher; Maxim, Peter G.; Loo, Billy W.; Hårdemark, Björn; Hynning, Elin

2015-01-01

Purpose: The aim of this work was to develop a treatment planning workflow for rapid radiotherapy delivered with very high-energy electron (VHEE) scanning pencil beams of 60–120 MeV and to study VHEE plans as a function of VHEE treatment parameters. Additionally, VHEE plans were compared to clinical state-of-the-art volumetric modulated arc therapy (VMAT) photon plans for three cases. Methods: VHEE radiotherapy treatment planning was performed by linking EGSnrc Monte Carlo (MC) dose calculations with inverse treatment planning in a research version of RayStation. In order to study the effect of VHEE treatment parameters on VHEE dose distributions, a MATLAB graphical user interface (GUI) for calculation of VHEE MC pencil beam doses was developed. Through the GUI, pediatric case MC simulations were run for a number of beam energies (60, 80, 100, and 120 MeV), number of beams (13, 17, and 36), pencil beam spot (0.1, 1.0, and 3.0 mm) and grid (2.0, 2.5, and 3.5 mm) sizes, and source-to-axis distance, SAD (40 and 50 cm). VHEE plans for the pediatric case calculated with the different treatment parameters were optimized and compared. Furthermore, 100 MeV VHEE plans for the pediatric case, a lung, and a prostate case were calculated and compared to the clinically delivered VMAT plans. All plans were normalized such that the 100% isodose line covered 95% of the target volume. Results: VHEE beam energy had the largest effect on the quality of dose distributions of the pediatric case. For the same target dose, the mean doses to organs at risk (OARs) decreased by 5%–16% when planned with 100 MeV compared to 60 MeV, but there was no further improvement in the 120 MeV plan. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams, but to a more modest degree (<8%). While pencil beam spacing and SAD had a small effect on VHEE dose distributions, 0.1–3 mm pencil beam sizes resulted in identical dose distributions. For the 100 MeV VHEE pediatric

SU-G-TeP4-08: Automating the Verification of Patient Treatment Parameters

Energy Technology Data Exchange (ETDEWEB)

DiCostanzo, D; Ayan, A; Woollard, J; Gupta, N [The Ohio State University, Columbus, OH (United States)

2016-06-15

Purpose: To automate the daily verification of each patient’s treatment by utilizing the trajectory log files (TLs) written by the Varian TrueBeam linear accelerator while reducing the number of false positives including jaw and gantry positioning errors, that are displayed in the Treatment History tab of Varian’s Chart QA module. Methods: Small deviations in treatment parameters are difficult to detect in weekly chart checks, but may be significant in reducing delivery errors, and would be critical if detected daily. Software was developed in house to read TLs. Multiple functions were implemented within the software that allow it to operate via a GUI to analyze TLs, or as a script to run on a regular basis. In order to determine tolerance levels for the scripted analysis, 15,241 TLs from seven TrueBeams were analyzed. The maximum error of each axis for each TL was written to a CSV file and statistically analyzed to determine the tolerance for each axis accessible in the TLs to flag for manual review. The software/scripts developed were tested by varying the tolerance values to ensure veracity. After tolerances were determined, multiple weeks of manual chart checks were performed simultaneously with the automated analysis to ensure validity. Results: The tolerance values for the major axis were determined to be, 0.025 degrees for the collimator, 1.0 degree for the gantry, 0.002cm for the y-jaws, 0.01cm for the x-jaws, and 0.5MU for the MU. The automated verification of treatment parameters has been in clinical use for 4 months. During that time, no errors in machine delivery of the patient treatments were found. Conclusion: The process detailed here is a viable and effective alternative to manually checking treatment parameters during weekly chart checks.

Experimental determination and verification of the parameters used in a proton pencil beam algorithm

International Nuclear Information System (INIS)

Szymanowski, H.; Mazal, A.; Nauraye, C.; Biensan, S.; Ferrand, R.; Murillo, M.C.; Caneva, S.; Gaboriaud, G.; Rosenwald, J.C.

2001-01-01

We present an experimental procedure for the determination and the verification under practical conditions of physical and computational parameters used in our proton pencil beam algorithm. The calculation of the dose delivered by a single pencil beam relies on a measured spread-out Bragg peak, and the description of its radial spread at depth features simple specific parameters accounting individually for the influence of the beam line as a whole, the beam energy modulation, the compensator, and the patient medium. For determining the experimental values of the physical parameters related to proton scattering, we utilized a simple relation between Gaussian radial spreads and the width of lateral penumbras. The contribution from the beam line has been extracted from lateral penumbra measurements in air: a linear variation with the distance collimator-point has been observed. Analytically predicted radial spreads within the patient were in good agreement with experimental values in water under various reference conditions. Results indicated no significant influence of the beam energy modulation. Using measurements in presence of Plexiglas slabs, a simple assumption on the effective source of scattering due to the compensator has been stated, leading to accurate radial spread calculations. Dose measurements in presence of complexly shaped compensators have been used to assess the performances of the algorithm supplied with the adequate physical parameters. One of these compensators has also been used, together with a reference configuration, for investigating a set of computational parameters decreasing the calculation time while maintaining a high level of accuracy. Faster dose computations have been performed for algorithm evaluation in the presence of geometrical and patient compensators, and have shown good agreement with the measured dose distributions

Preliminary research results for parameter diagnostics of intense pulsed ion beams

International Nuclear Information System (INIS)

Yang Hailiang; Qiu Aici; Sun Jianfeng; He Xiaoping; Tang Junping; Wang Haiyang; Li Jingya; Ren Shuqing; Huang Jianjun; Zhang Jiasheng; Peng Jianchang; Ouyang Xiaoping; Zhang Guoguang; Li Hongyu

2004-01-01

The preliminary experimental results for parameter diagnostics of intense pulsed ion beams from the FLASH II accelerator were reported. The ion number of an intense pulsed ion beam were experimentally determined by monitoring delayed radioactivity from protons induced nuclear reactions in a 12 C target. The prompt γ-rays and diode Bremsstrahlung X-rays were measured with PIN semi-conductor detector and a ST401 plastic scintillator detector. The Bremsstrahlung distribution outside of the drift tube was detected with a thermoluminescent detector and the shielding design was also determined. The current densities of beam were measured with biased ion collector array. The ion beams were also recorded with a CR-39 detector. (author)

Optimization of GATE and PHITS Monte Carlo code parameters for spot scanning proton beam based on simulation with FLUKA general-purpose code

Energy Technology Data Exchange (ETDEWEB)

Kurosu, Keita [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Department of Radiology, Osaka University Hospital, Suita, Osaka 565-0871 (Japan); Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Moskvin, Vadim P. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105 (United States)

2016-01-15

Spot scanning, owing to its superior dose-shaping capability, provides unsurpassed dose conformity, in particular for complex targets. However, the robustness of the delivered dose distribution and prescription has to be verified. Monte Carlo (MC) simulation has the potential to generate significant advantages for high-precise particle therapy, especially for medium containing inhomogeneities. However, the inherent choice of computational parameters in MC simulation codes of GATE, PHITS and FLUKA that is observed for uniform scanning proton beam needs to be evaluated. This means that the relationship between the effect of input parameters and the calculation results should be carefully scrutinized. The objective of this study was, therefore, to determine the optimal parameters for the spot scanning proton beam for both GATE and PHITS codes by using data from FLUKA simulation as a reference. The proton beam scanning system of the Indiana University Health Proton Therapy Center was modeled in FLUKA, and the geometry was subsequently and identically transferred to GATE and PHITS. Although the beam transport is managed by spot scanning system, the spot location is always set at the center of a water phantom of 600 × 600 × 300 mm{sup 3}, which is placed after the treatment nozzle. The percentage depth dose (PDD) is computed along the central axis using 0.5 × 0.5 × 0.5 mm{sup 3} voxels in the water phantom. The PDDs and the proton ranges obtained with several computational parameters are then compared to those of FLUKA, and optimal parameters are determined from the accuracy of the proton range, suppressed dose deviation, and computational time minimization. Our results indicate that the optimized parameters are different from those for uniform scanning, suggesting that the gold standard for setting computational parameters for any proton therapy application cannot be determined consistently since the impact of setting parameters depends on the proton irradiation

Optimization of GATE and PHITS Monte Carlo code parameters for spot scanning proton beam based on simulation with FLUKA general-purpose code

International Nuclear Information System (INIS)

Kurosu, Keita; Das, Indra J.; Moskvin, Vadim P.

2016-01-01

Spot scanning, owing to its superior dose-shaping capability, provides unsurpassed dose conformity, in particular for complex targets. However, the robustness of the delivered dose distribution and prescription has to be verified. Monte Carlo (MC) simulation has the potential to generate significant advantages for high-precise particle therapy, especially for medium containing inhomogeneities. However, the inherent choice of computational parameters in MC simulation codes of GATE, PHITS and FLUKA that is observed for uniform scanning proton beam needs to be evaluated. This means that the relationship between the effect of input parameters and the calculation results should be carefully scrutinized. The objective of this study was, therefore, to determine the optimal parameters for the spot scanning proton beam for both GATE and PHITS codes by using data from FLUKA simulation as a reference. The proton beam scanning system of the Indiana University Health Proton Therapy Center was modeled in FLUKA, and the geometry was subsequently and identically transferred to GATE and PHITS. Although the beam transport is managed by spot scanning system, the spot location is always set at the center of a water phantom of 600 × 600 × 300 mm 3 , which is placed after the treatment nozzle. The percentage depth dose (PDD) is computed along the central axis using 0.5 × 0.5 × 0.5 mm 3 voxels in the water phantom. The PDDs and the proton ranges obtained with several computational parameters are then compared to those of FLUKA, and optimal parameters are determined from the accuracy of the proton range, suppressed dose deviation, and computational time minimization. Our results indicate that the optimized parameters are different from those for uniform scanning, suggesting that the gold standard for setting computational parameters for any proton therapy application cannot be determined consistently since the impact of setting parameters depends on the proton irradiation technique

Method for surface treatment by electron beams

International Nuclear Information System (INIS)

Panzer, S.; Doehler, H.; Bartel, R.; Ardenne, T. von.

1985-01-01

The invention has been aimed at simplifying the technology and saving energy in modifying surfaces with the aid of electron beams. The described beam-object geometry allows to abandon additional heat treatments. It can be used for surface hardening

Optimization of GATE and PHITS Monte Carlo code parameters for uniform scanning proton beam based on simulation with FLUKA general-purpose code

Energy Technology Data Exchange (ETDEWEB)

Kurosu, Keita [Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Takashina, Masaaki; Koizumi, Masahiko [Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Moskvin, Vadim P., E-mail: vadim.p.moskvin@gmail.com [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)

2014-10-01

Although three general-purpose Monte Carlo (MC) simulation tools: Geant4, FLUKA and PHITS have been used extensively, differences in calculation results have been reported. The major causes are the implementation of the physical model, preset value of the ionization potential or definition of the maximum step size. In order to achieve artifact free MC simulation, an optimized parameters list for each simulation system is required. Several authors have already proposed the optimized lists, but those studies were performed with a simple system such as only a water phantom. Since particle beams have a transport, interaction and electromagnetic processes during beam delivery, establishment of an optimized parameters-list for whole beam delivery system is therefore of major importance. The purpose of this study was to determine the optimized parameters list for GATE and PHITS using proton treatment nozzle computational model. The simulation was performed with the broad scanning proton beam. The influences of the customizing parameters on the percentage depth dose (PDD) profile and the proton range were investigated by comparison with the result of FLUKA, and then the optimal parameters were determined. The PDD profile and the proton range obtained from our optimized parameters list showed different characteristics from the results obtained with simple system. This led to the conclusion that the physical model, particle transport mechanics and different geometry-based descriptions need accurate customization in planning computational experiments for artifact-free MC simulation.

Optimization of GATE and PHITS Monte Carlo code parameters for uniform scanning proton beam based on simulation with FLUKA general-purpose code

International Nuclear Information System (INIS)

Kurosu, Keita; Takashina, Masaaki; Koizumi, Masahiko; Das, Indra J.; Moskvin, Vadim P.

2014-01-01

Although three general-purpose Monte Carlo (MC) simulation tools: Geant4, FLUKA and PHITS have been used extensively, differences in calculation results have been reported. The major causes are the implementation of the physical model, preset value of the ionization potential or definition of the maximum step size. In order to achieve artifact free MC simulation, an optimized parameters list for each simulation system is required. Several authors have already proposed the optimized lists, but those studies were performed with a simple system such as only a water phantom. Since particle beams have a transport, interaction and electromagnetic processes during beam delivery, establishment of an optimized parameters-list for whole beam delivery system is therefore of major importance. The purpose of this study was to determine the optimized parameters list for GATE and PHITS using proton treatment nozzle computational model. The simulation was performed with the broad scanning proton beam. The influences of the customizing parameters on the percentage depth dose (PDD) profile and the proton range were investigated by comparison with the result of FLUKA, and then the optimal parameters were determined. The PDD profile and the proton range obtained from our optimized parameters list showed different characteristics from the results obtained with simple system. This led to the conclusion that the physical model, particle transport mechanics and different geometry-based descriptions need accurate customization in planning computational experiments for artifact-free MC simulation

Bending analysis of agglomerated carbon nanotube-reinforced beam resting on two parameters modified Vlasov model foundation

Science.gov (United States)

Ghorbanpour Arani, A.; Zamani, M. H.

2018-06-01

The present work deals with bending behavior of nanocomposite beam resting on two parameters modified Vlasov model foundation (MVMF), with consideration of agglomeration and distribution of carbon nanotubes (CNTs) in beam matrix. Equivalent fiber based on Eshelby-Mori-Tanaka approach is employed to determine influence of CNTs aggregation on elastic properties of CNT-reinforced beam. The governing equations are deduced using the principle of minimum potential energy under assumption of the Euler-Bernoulli beam theory. The MVMF required the estimation of γ parameter; to this purpose, unique iterative technique based on variational principles is utilized to compute value of the γ and subsequently fourth-order differential equation is solved analytically. Eventually, the transverse displacements and bending stresses are obtained and compared for different agglomeration parameters, various boundary conditions simultaneously and variant elastic foundation without requirement to instate values for foundation parameters.

Measurement of the main and critical parameters for optimal laser treatment of heart disease

Science.gov (United States)

Kabeya, FB; Abrahamse, H.; Karsten, AE

2017-10-01

Laser light is frequently used in the diagnosis and treatment of patients. As in traditional treatments such as medication, bypass surgery, and minimally invasive ways, laser treatment can also fail and present serious side effects. The true reason for laser treatment failure or the side effects thereof, remains unknown. From the literature review conducted, and experimental results generated we conclude that an optimal laser treatment for coronary artery disease (named heart disease) can be obtained if certain critical parameters are correctly measured and understood. These parameters include the laser power, the laser beam profile, the fluence rate, the treatment time, as well as the absorption and scattering coefficients of the target treatment tissue. Therefore, this paper proposes different, accurate methods for the measurement of these critical parameters to determine the optimal laser treatment of heart disease with a minimal risk of side effects. The results from the measurement of absorption and scattering properties can be used in a computer simulation package to predict the fluence rate. The computing technique is a program based on the random number (Monte Carlo) process and probability statistics to track the propagation of photons through a biological tissue.

Electron beam application in gas waste treatment in China

International Nuclear Information System (INIS)

Wu Haifeng

2003-01-01

In the most recent decade, electron beam waste treatment technology attracted serious attention from environment policymaker and industrial leaders in power industry in China. Starting in middle of 1980's, Chinese research institute began experiment of electron beam treatment on flue gas. By the end of 2000, two 10,000 cubic meters per hour small scale electron beam gas purifying station were established in Sichuang province and Beijing. Several electron beam gas purifying demonstration projects are under construction. With robust economy and strong energy demand, needless to say, in near future, electron beam gas purifying technology will have a bright prospect in China. (author)

Development of time-resolved optical measurement and diagnostic system for parameters of high current and pulsed electron beam

International Nuclear Information System (INIS)

Jiang Xiaoguo; Wang Yuan; Yang Guojun; Xia Liansheng; Li Hong; Zhang Zhuo; Liao Shuqing; Shi Jinshui

2013-01-01

The beam parameters measurement is the most important work for the study of linear induction accelerator(LIA). The beam parameters are important to evaluate the character of the beam. The demands of beam parameters measurement are improving while the development of accelerator is improving. The measurement difficulty feature higher time-resolved ability, higher spatial resolution, larger dynamic range and higher intuitionistic view data. The measurement technology of beam spot, beam emittance, beam energy have been developed for the past several years. Some high performance equipment such as high speed framing camera are developed recently. Under this condition, the relative integrated optical measurement and diagnostic system for the beam parameters is developed based on several principles. The system features time-resolved ability of up to 2 ns, high sensitivity and large dynamic range. The processing program is compiled for the data process and the local real-time process is reached. The measurement and diagnostic system has provided full and accurate data for the debug work and has been put into applications. (authors)

Monte Carlo investigation of the effect of small cutouts on beam profile parameters of 12 and 14 MeV electron beams

International Nuclear Information System (INIS)

Khaledi, Navid; Arbabi, Azim; Sardari, Dariush; Rabie Mahdavi, Seied; Aslian, Hossein; Dabaghi, Moloud; Sheibani, Kourosh

2013-01-01

Cutouts, which are used as field-shaping shield, affect several electron beam parameters. These effects are more observable for small field sizes and high energy electron beams. Owing to the fact that small fields prevent the lateral scatter equilibrium, at higher energies larger field radius is required for the establishment of lateral equilibrium. The profile curves are derived from circular, triangular, and square cutout shapes and size placed in a 10 × 10 cm 2 electron applicator. These profile curves are obtained using parallel plane type ion chamber at the R 100 , R 90 , R 80 and R 50 depths. Correspondingly, the source surface distance is 100 cm. In this study MCNP Monte Carlo (MC) simulation was used to compare Percentage Depth Dose (PDD) and Profile of electron beams. Monte Carlo and measured results showed a good compliance for PDD and beam profile. The measurements and calculations showed that as the field width decreases, the Flatness and Penumbra Ratio also decreases. In other words, flatter plateau was available for larger fields. Also the Coverage Ratio for each of the profiles is presented. The flatness and symmetry values for triangle shapes were greater than the two other shapes. Knowledge of these changes are significant in radiation therapy. Accordingly, a comparison between the Monte Carlo data and the measured results can be beneficial for treatment simulation and development of treatment planning systems. - Highlights: ► Mesh Tally 1 and pedep keyword were used to calculate the PDD and profile values. ► In measurement the coverage for larger fields and fewer doses are better. ► By increasing the depth, the flatness and symmetry values were increased. ► The worst flatness and symmetry (between 3 compared shapes) belonged to triangle. ► The given Penumbra and Coverage Ratio can be helpful for PTV margin and coverage

Exhaust gas treatment by electron beam irradiation

International Nuclear Information System (INIS)

Shibamura, Yokichi; Suda, Shoichi; Kobayashi, Toshiki

1991-01-01

Among global environmental problems, atmospheric pollution has been discussed since relatively old days, and various countermeasures have been taken, but recently in connection with acid rain, the efficient and economical treatment technology is demanded. As the denitration and desulfurization technology for the exhaust gas from the combustion of fossil fuel, the incineration of city trash and internal combustion engines, three is the treatment method by electron beam irradiation. By irradiating electron beam to exhaust gas, nitrogen oxides and sulfur oxides are oxidized to nitric acid and sulfuric acid, and by promoting the neutralization of these acids with injected alkali, harmless salts are recovered. This method has the merit that nitrogen oxides and surfur oxides can be removed efficiently with a single system. In this report, as for the exhaust gas treatment by electron beam irradiation, its principle, features, and the present status of research and development are described, and in particular, the research on the recent exhaust gas treatment in city trash incineration is introduced. This treatment method is a dry process, accordingly, waste water disposal is unnecessary. The reaction products are utilized as fertilizer, and waste is not produced. (K.I.)

Strip Ionization Chamber as Beam Monitor in the Proton Therapy Eye Treatment

Science.gov (United States)

Marchetto, F.; Cirio, R.; Garella, M. A.; Giordanengo, S.; Boriano, A.; Givehchi, N.; La Rosa, A.; Peroni, C.; Donetti, M.; Bourhaleb, F.; Pitta', G.; Cirrone, G. A. P.; Cuttone, G.; Raffaele, L.; Sabini, M. G.; Valastro, L.

2006-04-01

Since spring 2002, ocular pathologies have been treated in Catania at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) within a collaboration between INFN Laboratori Nazionali del Sud (LNS), Physics Department, Ophthalmology Institute, Radiology Institute of the Catania University and CSFNSM Catania. A beam line from a 62 MeV Superconducting Cyclotron is used to treat shallow tumors. The beam is conformed to the tumor shape with a passive delivery system. A detector system has been developed in collaboration with INFN-Torino to be used as real time beam monitor. The detector, placed upstream of the patient collimator, consists of two parallel plate ionization chambers with the anode segmented in strips. Each anode is made of 0.5 mm-wide 256 strips corresponding to (12.8 × 12.8) cm2 sensitive area. With the two strip ionization chambers one can measure the relevant beam parameters during treatment to probe both asymmetry and flatness. In the test carried out at CATANA the detector has been used under different and extreme beam conditions. Preliminary results are given for profiles and skewness, together with a comparison with reference detectors.

An interactive beam-weight optimization tool for three-dimensional radiotherapy treatment planning

International Nuclear Information System (INIS)

Burba, S.; Gardey, K.; Nadobny, J.; Stalling, D.; Seebass, M.; Beier, J.; Wust, P.; Budach, V.; Felix, R.

1997-01-01

that the beam configuration is inappropriate. Possible reasons for this may be that part of the target volume may have been missed by one or more beams, or there may have been excessive beam overlap. The beam-weight optimization tool can then be used to warn the treatment planner of this occurrence, thus avoiding excessive planner time in attempting to find an acceptable solution. In addition the possibilities of the three-dimensional representation of dose distribution offered by the high-performance visualization workstation could be combined with the first attempt at a feasibility search for enhancing the degree of interactive optimization of treatment planning. Conclusions: We have demonstrated how a beam-weight optimization tool can be incorporated into a treatment planning system offering plenty of visualization tools for realizing virtual therapy planning. Further software development is required with respect to the acceleration of calculation time, the implication of borderline cases and the inclusion of further biological and clinical relevant parameters according to the definition of further objective functions. The software tools developed up to now constitute the basis for the development of an alternative voxel oriented mathematical formulation of inverse treatment planning for optimizing conformation therapy

SU-F-T-521: Flattening-Filter-Free Beam Parameters Comparison From Different Linac Machine Types

Energy Technology Data Exchange (ETDEWEB)

Hussain, A [King Faisal Specialist Hospital, Riyadh, Saudi Arabia, Arkansas Cancer Institute, Pine Bluff, AR (Saudi Arabia)

2016-06-15

Purpose: Novel linac machines, TrueBeam (TB) and Elekta Versa have updated head designing and software control system, include flattening-filter-free (FFF) photon and electron beams. Later on FFF beams were also introduced on C-Series machines. In this work FFF beams for same energy 6MV but from different machine versions were studied with reference to beam data parameters. Methods: The 6MV-FFF percent depth doses, profile symmetry and flatness, dose rate tables, and multi-leaf collimator (MLC) transmission factors were measured during commissioning process of both C-series and Truebeam machines. The scanning and dosimetric data for 6MV-FFF beam from Truebeam and C-Series linacs was compared. A correlation of 6MV-FFF beam from Elekta Versa with that of Varian linacs was also found. Results: The scanning files were plotted for both qualitative and quantitative analysis. The dosimetric leaf gap (DLG) for C-Series 6MV-FFF beam is 1.1 mm. Published values for Truebeam dosimetric leaf gap is 1.16 mm. 6MV MLC transmission factor varies between 1.3 % and 1.4 % in two separate measurements and measured DLG values vary between 1.32 mm and 1.33 mm on C-Series machine. MLC transmission factor from C-Series machine varies between 1.5 % and 1.6 %. Some of the measured data values from C-Series FFF beam are compared with Truebeam representative data. 6MV-FFF beam parameter values like dmax, OP factors, beam symmetry and flatness and additional parameters for C-Series and Truebeam liancs will be presented and compared in graphical form and tabular data form if selected. Conclusion: The 6MV flattening filter (FF) beam data from C-Series & Truebeam and 6MV-FFF beam data from Truebeam has already presented. This particular analysis to compare 6MV-FFF beam from C-Series and Truebeam provides opportunity to better elaborate FFF mode on novel machines. It was found that C-Series and Truebeam 6MV-FFF dosimetric and beam data was quite similar.

Ion-beam-induced aggregation in polystyrene: The influence of the molecular parameters

International Nuclear Information System (INIS)

Puglisi, O.; Licciardello, A.; Calcagno, L.; Foti, G.

1988-01-01

The formation of an insoluble gel under ion-beam bombardment is governed by ion-beam parameters and target parameters. Here reported is a study of the influence of the target molecular parameters on the sol--gel transition of ion-bombarded polystyrene with particular emphasis for the number-average molecular weight M-bar/sub n/. It is shown that the main parameter is the number of macromolcules of the film so that by adopting a ''corrected'' fluence F/n (ions per macromolecule), the different curves of the various polymers collapse in only one universal curve. The importance of the ''corrected'' fluence is shown also at molecular level and the MWD of the various polymers is similar at equal F/n values. An experimental model is outlined which explains the sol--gel transition on the basis of transition from an isolated-track regime to an overlap regime where the formation of insoluble giant macromolecules occurs

Diffraction corrections for second harmonic beam fields and effects on the nonlinearity parameter evaluation

Energy Technology Data Exchange (ETDEWEB)

Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

2016-04-15

The nonlinearity parameter is frequently measured as a sensitive indicator in damaged material characterization or tissue harmonic imaging. Several previous studies have employed the plane wave solution, and ignored the effects of beam diffraction when measuring the non-linearity parameter β. This paper presents a multi-Gaussian beam approach to explicitly derive diffraction corrections for fundamental and second harmonics under quasilinear and paraxial approximation. Their effects on the nonlinearity parameter estimation demonstrate complicated dependence of β on the transmitter-receiver geometries, frequency, and propagation distance. The diffraction effects on the non-linearity parameter estimation are important even in the nearfield region. Experiments are performed to show that improved β values can be obtained by considering the diffraction effects.

Properties and parameters of the electron beam injected into the mirror magnetic trap of a plasma accelerator

Energy Technology Data Exchange (ETDEWEB)

Andreev, V. V., E-mail: temple18@mail.ru; Novitsky, A. A.; Vinnichenko, L. A.; Umnov, A. M.; Ndong, D. O. [Peoples’ Friendship University of Russia (Russian Federation)

2016-03-15

The parameters of the injector of an axial plasma beam injected into a plasma accelerator operating on the basis of gyroresonance acceleration of electrons in the reverse magnetic field are determined. The trapping of the beam electrons into the regime of gyroresonance acceleration is numerically simulated by the particle- in-cell method. The optimal time of axial injection of the beam into a magnetic mirror trap is determined. The beam parameters satisfying the condition of efficient particle trapping into the gyromagnetic autoresonance regime are found.

A method to combine three dimensional dose distributions for external beam and brachytherapy radiation treatments for gynecological neoplasms

International Nuclear Information System (INIS)

Narayana, V.; Sahijdak, W.M.; Orton, C.G.

1997-01-01

Purpose: Radiation treatment of gynecological neoplasms, such as cervical carcinoma, usually combines external radiation therapy with one or more intracavitary brachytherapy applications. Although the dose from external beam radiation therapy and brachytherapy can be calculated and displayed in 3D individually, the dose distributions are not combined. At most, combined point doses are calculated for select points using various time-dose models. In this study, we present a methodology to combine external beam and brachytherapy treatments for gynecological neoplasms. Material and Methods: Three dimensional bio-effect treatment planning to obtain complication probability has been outlined. CT scans of the patient's pelvis with the gynecological applicator in place are used to outline normal tissue and tumor volumes. 3D external beam and brachytherapy treatment plans are developed separately and an external beam dose matrix and a brachytherapy dose matrix was calculated. The dose in each voxel was assumed to be homogeneous. The physical dose in each voxel of the dose matrix was then converted into extrapolated response dose (ERD) based on the linear quadratic model that accounts for the dose per fraction, number of fractions, dose rate, and complete or incomplete repair of sublethal damage (time between fractions). The net biological dose delivered was obtained by summing the ERD grids from external beam and brachytherapy since there was complete repair of sublethal damage between external beam and brachytherapy treatments. The normal tissue complication probability and tumor control probability were obtained using the biological dose matrix based on the critical element model. Results: The outlined method of combining external beam and brachytherapy treatments was implemented on gynecological treatments using an applicator for brachytherapy treatments. Conclusion: Implementation of the biological dose calculation that combine different modalities is extremely useful

Influence of core model parameters on the characteristics of neutron beams of the research reactor

Directory of Open Access Journals (Sweden)

N. A. Khafizova

2013-12-01

Full Text Available IRT MEPhI reactor is equipped with a number of facilities at horizontal experimental channels (HEC. Knowing of parameters influencing spatio-angular distribution of irradiation fields is essential for each application area. The research for neutron capture therapy (NCT facility at HEC of the reactor was made. Calculation methods have been used to estimate how the reactor core parameters influence neutron beam characteristics at the HEC output. The impact of neutron source model in Monte Carlo calculations by MCNP code on the parameters of neutron and secondary photon field at the output of irradiation beam tubes of research reactor is estimated. The study shows that specifying neutron source with fission reaction rate distribution in SDEF option gives almost the same results as criticality calculation considered the most accurate. Our calculations show that changes of the core operational parameters have insignificant influence on characteristics of neutron beams at HEC output.

Choice of primary transducers of beam parameters for measuring and control systems of charged particle accelerators

International Nuclear Information System (INIS)

Rybin, V.M.

1981-01-01

Investigations on classification of primary transducers (pT) of the main parameters of charged particle beams are conducted for development of the common series on the base of program- controlled module systems for measuring the parameters of charged particle beams. The PT classification is exercised by: the physical principle of single transformation, the degree of effect on the beam, principle of operation, design, performance, location. It is shown that the optimal choice of PT and their parameters should be necessarily executed in several stages: estimation of the limiting possibilities of PT; choice of PT by time and metrological characteristics as well as sensitivity for the determined operation conditions; choice of the PT by the degree of effect on the beam: choice of the PT type with account of its design performance and location, determination of PT parameters with account of possibility of information, energy and design compatibility of the used standard. The classification results of magnetoinduction and acoustic transducers have shown that the number of their modifications does not exceed 100 [ru

Monte Carlo Investigation of Photon Beam Characteristics and its Variation with Incident Electron Beam Parameters for Indigenous Medical Linear Accelerator.

Science.gov (United States)

Mishra, Subhalaxmi; Dixit, P K; Selvam, T Palani; Yavalkar, Sanket S; Deshpande, D D

2018-01-01

A Monte Carlo model of a 6 MV medical linear accelerator (linac) unit built indigenously was developed using the BEAMnrc user code of the EGSnrc code system. The model was benchmarked against the measurements. Monte Carlo simulations were carried out for different incident electron beam parameters in the study. Simulation of indigenously developed linac unit has been carried out using the Monte Carlo based BEAMnrc user-code of the EGSnrc code system. Using the model, percentage depth dose (PDD), and lateral dose profiles were studied using the DOSXYZnrc user code. To identify appropriate electron parameters, three different distributions of electron beam intensity were investigated. For each case, the kinetic energy of the incident electron was varied from 6 to 6.5 MeV (0.1 MeV increment). The calculated dose data were compared against the measurements using the PTW, Germany make RFA dosimetric system (water tank MP3-M and 0.125 cm 3 ion chamber). The best fit of incident electron beam parameter was found for the combination of beam energy of 6.2 MeV and circular Gaussian distributed source in X and Y with FWHM of 1.0 mm. PDD and beam profiles (along both X and Y directions) were calculated for the field sizes from 5 cm × 5 cm to 25 cm × 25 cm. The dose difference between the calculated and measured PDD and profile values were under 1%, except for the penumbra region where the maximum deviation was found to be around 2%. A Monte Carlo model of indigenous linac (6 MV) has been developed and benchmarked against the measured data.

Determination of beam characteristic parameters for a linear accelerator

International Nuclear Information System (INIS)

Lima, D.A. de.

1978-01-01

A mechanism to determine electron beam characteristic parameters of a linear accelerator was constructed. The mechanism consists in an electro-calorimeter and an accurate optical densitometer. The following parameters: mean power, mean current, mean energy/particle, pulse Width, pulse amplitude dispersion, and pulse frequency, operating the 2 MeV linear accelerator of CBPF (Brazilian Center pf Physics Researches). The optical isodensity curves of irradiated glass lamellae were obtained, providing information about focus degradation penetration direction in material and the reach of particle. The point to point dose distribution in the material from optical density curves were obtained, using a semi empirical and approached model. (M.C.K.) [pt

Treatment of supernatant from sewage sludge by elctron beam irradiation

International Nuclear Information System (INIS)

Arai, Hidehiko; Sugiyama, Masashi; Shimizu, Ken.

1988-01-01

Part of the results was presented on the investigation of treatment of supernatant from sewage sludge by combination of electron beam irradiation and microbiological treatment. Supernatant is electron-beam irradiated after microbiologically treated, and then treated microbiologically again. Based this method, by irradiation of 10 kGy, chemical oxygen demand (COD) in supernatant can be decreased lower than 30 ppm. Moreover, electron-beam irradiation induces remarkable decolorization and deodorization. (author)

Advanced Oxidation Treatment of Drinking Water and Wastewater Using High-energy Electron Beam Irradiation

Directory of Open Access Journals (Sweden)

Abbas Behjat

2007-03-01

Full Text Available Application of electron beam as a strong oxidation method for disinfection of drinking water and wastewater has been investigated. Drinking water samples were prepared from wells in rock zones in Yazd Province. Wastewater samples were collected from Yazd Wastewater Treatment Plant. Samples were irradiated by 10 MeV electron beam accelerator at Yazd Radiation Processing Center. The irradiation dose range varied from 0.5-5 kGy. Biological parameters and microbial agents such as aerobic mesophiles and coliforms including E. coli count before and after irradiation versus irradiation dose were obtained using MPN method. The data obtained from irradiated water and wastewater were compared with un-irradiated (control samples. The results showed a removal of 90% of all microorganisms at irradiation doses below 5 kGy, suggesting electron beam irradiation as an effective method for disinfection of wastewater.

Online Measurement of LHC Beam Parameters with the ATLAS High Level Trigger

CERN Document Server

Strauss, E; The ATLAS collaboration

2011-01-01

We present an online measurement of the LHC beam parameters in ATLAS using the High Level Trigger (HLT). When a significant change is detected in the measured beamspot, it is distributed to the HLT. There, trigger algorithms like b-tagging which calculate impact parameters or decay lengths benefit from a precise, up-to-date set of beamspot parameters. Additionally, online feedback is sent to the LHC operators in real time. The measurement is performed by an algorithm running on the Level 2 trigger farm, leveraging the high rate of usable events. Dedicated algorithms perform a full scan of the silicon detector to reconstruct event vertices from registered tracks. The distribution of these vertices is aggregated across the farm and their shape is extracted through fits every 60 seconds to determine the beamspot position, size, and tilt. The reconstructed beam values are corrected for detector resolution effects, measured in situ using the separation of vertices whose tracks have been split into two collections....

Online measurement of LHC beam parameters with the ATLAS High Level Trigger

CERN Document Server

Strauss, E; The ATLAS collaboration

2011-01-01

We present an online measurement of the LHC beam parameters in ATLAS using the High Level Trigger (HLT). When a significant change is detected in the measured beamspot, it is distributed to the HLT. There, trigger algorithms like b-tagging which calculate impact parameters or decay lengths benefit from a precise,up-to-date set of beamspot parameters. Additionally, online feedback is sent to the LHC operators in real time. The measurement is performed by an algorithm running on the Level 2 trigger farm, leveraging the high rate of usable events. Dedicated algorithms perform a full scan of the silicon detector to reconstruct event vertices from registered tracks. The distribution of these vertices is aggregated across the farm and their shape is extracted through fits every 60 seconds to determine the beamspot position, size, and tilt. The reconstructed beam values are corrected for detector resolution effects, measured in situ using the separation of vertices whose tracks have been split into two collections. ...

Construction of Industrial Electron Beam Plant for Wastewater Treatment

International Nuclear Information System (INIS)

Han, B.; Kim, J.; Kim, Y.; Kim, S.; Lee, M.; Choi, J.; Ahn, S.; Makarov, I.E.; Ponomarev, A.V.

2004-01-01

A pilot plant for treating 1,000 m3/day of dyeing wastewater with e-beam has been constructed and operated since 1998 in Daegu, Korea together with the biological treatment facility. The wastewater from various stages of the existing purification process has been treated with electron beam in this plant, and it gave rise to elaborate the optimal technology of the electron beam treatment of wastewater with increased reliability at instant changes in the composition of wastewater. Installation of the e-beam pilot plant resulted in decolorizing and destructive oxidation of organic impurities in wastewater, appreciable to reduction of chemical reagent consumption, in reduction of the treatment time, and in increase in flow rate limit of existing facilities by 30-40%. Industrial plant for treating 10,000 m3/day, based upon the pilot experimental result, is under construction and will be finished by 2005. This project is supported by the International Atomic Energy Agency (IAEA) and Korean Government

Electron beam collimation with a photon MLC for standard electron treatments

Science.gov (United States)

Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

2018-01-01

Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

Generating AN Optimum Treatment Plan for External Beam Radiation Therapy.

Science.gov (United States)

Kabus, Irwin

1990-01-01

The application of linear programming to the generation of an optimum external beam radiation treatment plan is investigated. MPSX, an IBM linear programming software package was used. All data originated from the CAT scan of an actual patient who was treated for a pancreatic malignant tumor before this study began. An examination of several alternatives for representing the cross section of the patient showed that it was sufficient to use a set of strategically placed points in the vital organs and tumor and a grid of points spaced about one half inch apart for the healthy tissue. Optimum treatment plans were generated from objective functions representing various treatment philosophies. The optimum plans were based on allowing for 216 external radiation beams which accounted for wedges of any size. A beam reduction scheme then reduced the number of beams in the optimum plan to a number of beams small enough for implementation. Regardless of the objective function, the linear programming treatment plan preserved about 95% of the patient's right kidney vs. 59% for the plan the hospital actually administered to the patient. The clinician, on the case, found most of the linear programming treatment plans to be superior to the hospital plan. An investigation was made, using parametric linear programming, concerning any possible benefits derived from generating treatment plans based on objective functions made up of convex combinations of two objective functions, however, this proved to have only limited value. This study also found, through dual variable analysis, that there was no benefit gained from relaxing some of the constraints on the healthy regions of the anatomy. This conclusion was supported by the clinician. Finally several schemes were found that, under certain conditions, can further reduce the number of beams in the final linear programming treatment plan.

Nanosecond air breakdown parameters for electron and microwave beam propagation

International Nuclear Information System (INIS)

Ali, A.W.

1988-01-01

Air breakdown by avalanche ionization plays an important role in the electron beam and microwave propagations. For high electric fields and short pulse applications one needs avalanche ionization parameters for modeling and scaling of experimental devices. However, the breakdown parameters, i.e., the ionization frequency vs E/p (volt. cm -1 . Torr -1 ) in air is uncertain for very high values of E/P. A review is given of the experimental data for the electron drift velocity, the Townsend ionization coefficient in N 2 and O 2 and the ionization frequency and the collision frequency for momentum transfer in air are developed. (author)

Specialty flat-top beam delivery fibers with controlled beam parameter product

Science.gov (United States)

Jollivet, C.; Farley, K.; Conroy, M.; Abramczyk, J.; Belke, S.; Becker, F.; Tankala, K.

2016-03-01

Beam delivery fibers have been used widely for transporting the optical beams from the laser to the subject of irradiation in a variety of markets including industrial, medical and defense applications. Standard beam delivery fibers range from 50 to 1500 μm core diameter and are used to guide CW or pulsed laser light, generated by solid state, fiber or diode lasers. Here, we introduce a novel fiber technology capable of simultaneously controlling the beam profile and the angular divergence of single-mode (SM) and multi-mode (MM) beams using a single-optical fiber. Results of beam transformation from a SM to a MM beam with flat-top intensity profile are presented in the case of a controlled BPP at 3.8 mm*mrad. The scaling capabilities of this flat-top fiber design to achieve a range of BPP values while ensuring a flat-top beam profile are discussed. In addition, we demonstrate, for the first time to the best of our knowledge, the homogenizer capabilities of this novel technology, able to transform random MM beams into uniform flat-top beam profiles with very limited impact on the beam brightness. This study is concluded with a discussion on the scalability of this fiber technology to fit from 50 up to 1500 μm core fibers and its potential for a broader range of applications.

Ion beam treatment of polymers application aspects from medicine to space

CERN Document Server

Kondyurin, Alexey; McKenzie, David

2010-01-01

Polymer materials are used in different fields of industries, from microelectronice to medicine. Ion beam implantation is method of surface modification when surface properties must be significantly changed and bulk properties of material must be saved. Ion Beam Treatment of Polymers contains results of polymer investigations and techniques development in the field of polymer modification by high energy ion beams. This book is intended for specialists in polymer science who have interest to use an ion beam treatment for improvement of polymer properties, for specialists in physics who search

Measurement of the $\\beta$-asymmetry parameter in $^{35}$Ar decay with a laser polarized beam

CERN Multimedia

With this proposal we request beam time for the first two phases of a project that aims at measuring the $\\beta$-asymmetry parameter of the mirror $\\beta$-decay branch in $^{35}$Ar using an optically polarized Ar atom beam. The final goal of the experiment is to measure this parameter to a precision of 0.5%. This will allow the most precise determination of the V$_{ud}$ quark mixing matrix element from all the mirror transitions with an absolute uncertainty of 0.0007. The proposal will be presented in phases and we ask here 11 shifts (7 on-line + 4 off-line) for phase 1 and 15 shifts (6 on-line and 9 off-line) for phase 2. Phase 1 aims at establishing the optimal laser polarization scheme as well as the best implantation host for maintaining the polarization. Phase 2 aims at enhancing the beam polarization by removing the unpolarized part of the beam using re-ionization.

Comparisons of hydrodynamic beam models with kinetic treatments

International Nuclear Information System (INIS)

Boyd, J.K.; Mark, J.W.; Sharp, W.M.; Yu, S.S.

1983-01-01

Hydrodynamic models have been derived by Mark and Yu and by others to describe energetic self-pinched beams, such as those used in ion-beam fusion. The closure of the Mark-Yu model is obtained with adiabatic assumptions mathematically analogous to those of Chew, Goldberger, and Low for MHD. The other models treated here use an ideal gas closure and a closure by Newcomb based on an expansion in V/sub th//V/sub z/. Features of these hydrodynamic beam models are compared with a kinetic treatment

Parameters affecting profile shape of a high energy low current thin ion beam. Vol. 2

Energy Technology Data Exchange (ETDEWEB)

Abdel Salam, F W; Moustafa, O A; El-Khabeary, H [Accelerators Department, Nuclear Research Center, Atomic Energy Authority, Cairo, (Egypt)

1996-03-01

The shape of the profile of a high energy, low current beam of finite length has beam investigated. The beam profile shape depends on the initial beam radius, beam perveance, atomic mass number, charge state of ions, and beam length. These parameters can affect the relation between the initial beam radius and the corresponding final one. An optimum initial beam radius corresponding to minimum final beam at the target has been formulated and the relation between them is deduced taking account of the space charge effect. The minimum beam radius at the target was found to be equal to 2.3 of the optimum initial radius. It is concluded that in order to obtain a small beam radius at a target placed at a finite distance from an ion source, a beam of a low perveance, low atomic mass number and high number of electronic charge is required. This is an important detection for micro machining applications using the oscillating electron ion source which produces nearly paraxial thin beam of low perveance. 12 figs.

Parameter Deduction and Accuracy Analysis of Track Beam Curves in Straddle-type Monorail Systems

Directory of Open Access Journals (Sweden)

Xiaobo Zhao

2015-12-01

Full Text Available The accuracy of the bottom curve of a PC track beam is strongly related to the production quality of the entire beam. Many factors may affect the parameters of the bottom curve, such as the superelevation of the curve and the deformation of a PC track beam. At present, no effective method has been developed to determine the bottom curve of a PC track beam; therefore, a new technique is presented in this paper to deduce the parameters of such a curve and to control the accuracy of the computation results. First, the domain of the bottom curve of a PC track beam is assumed to be a spindle plane. Then, the corresponding supposed top curve domain is determined based on a geometrical relationship that is the opposite of that identified by the conventional method. Second, several optimal points are selected from the supposed top curve domain according to the dichotomy algorithm; the supposed top curve is thus generated by connecting these points. Finally, one rigorous criterion is established in the fractal dimension to assess the accuracy of the assumed top curve deduced in the previous step. If this supposed curve coincides completely with the known top curve, then the assumed bottom curve corresponding to the assumed top curve is considered to be the real bottom curve. This technique of determining the bottom curve of a PC track beam is thus proven to be efficient and accurate.

On- and off-line monitoring of ion beam treatment

Energy Technology Data Exchange (ETDEWEB)

Parodi, Katia, E-mail: katia.parodi@lmu.de

2016-02-11

Ion beam therapy is an emerging modality for high precision radiation treatment of cancer. In comparison to conventional radiation sources (photons, electrons), ion beams feature major dosimetric advantages due to their finite range with a localized dose deposition maximum, the Bragg peak, which can be selectively adjusted in depth. However, due to several sources of treatment uncertainties, full exploitation of these dosimetric advantages in clinical practice would require the possibility to visualize the stopping position of the ions in vivo, ideally in real-time. To this aim, different imaging methods have been proposed and investigated, either pre-clinically or even clinically, based on the detection of prompt or delayed radiation following nuclear interaction of the beam with the irradiated tissue. However, the chosen or ad-hoc developed instrumentation has often relied on technologies originally conceived for different applications, thus compromising on the achievable performances for the sake of cost-effectiveness. This contribution will review major examples of used instrumentation and related performances, identifying the most promising detector developments for next generation devices especially dedicated to on-line monitoring of ion beam treatment. Moreover, it will propose an original combination of different techniques in a hybrid detection scheme, aiming to make the most of complementary imaging methods and open new perspectives of image guidance for improved precision of ion beam therapy.

SU-D-19A-06: The Effect of Beam Parameters On Very High-Energy Electron Radiotherapy: A Planning Study

Energy Technology Data Exchange (ETDEWEB)

Palma, B; Bazalova, M; Qu, B; Loo, B; Maxim, P [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Hardemark, B; Hynning, E [RaySearch Laboratories AB, Stockholm (Sweden)

2014-06-01

Purpose: We evaluated the effect of very high-energy electron (VHEE) beam parameters on the planning of a lung cancer case by means of Monte Carlo simulations. Methods: We simulated VHEE radiotherapy plans using the EGSnrc/BEAMnrc-DOSXYZnrc code. We selected a lung cancer case that was treated with 6MV photon VMAT to be planned with VHEE. We studied the effect of beam energy (80 MeV, 100 MeV, and 120 MeV), number of equidistant beams (16 or 32), and beamlets sizes (3 mm, 5 mm or 7 mm) on PTV coverage, sparing of organs at risk (OARs) and dose conformity. Inverse-planning optimization was performed in a research version of RayStation (RaySearch Laboratories AB) using identical objective functions and constraints for all VHEE plans. Results: Similar PTV coverage and dose conformity was achieved by all the VHEE plans. The 100 MeV and 120 MeV VHEE plans were equivalent amongst them and were superior to the 80 MeV plan in terms of OARs sparing. The effect of using 16 or 32 equidistant beams was a mean difference in average dose of 2.4% (0%–7.7%) between the two plans. The use of 3 mm beamlet size systematically reduced the dose to all the OARs. Based on these results we selected the 100MeV-16beams-3mm-beamlet-size plan to compare it against VMAT. The selected VHEE plan was more conformal than VMAT and improved OAR sparing (heart and trachea received 125% and 177% lower dose, respectively) especially in the low-dose region. Conclusion: We determined the VHEE beam parameters that maximized the OAR dose sparing and dose conformity of the actually delivered VMAT plan of a lung cancer case. The selected parameters could be used for the planning of other treatment sites with similar size, shape, and location. For larger targets, a larger beamlet size might be used without significantly increasing the dose. B Palma: None. M Bazalova: None. B Hardemark: Employee, RaySearch Americas. E Hynning: Employee, RaySearch Americas. B Qu: None. B Loo Jr.: Research support, Ray

SU-D-19A-06: The Effect of Beam Parameters On Very High-Energy Electron Radiotherapy: A Planning Study

International Nuclear Information System (INIS)

Palma, B; Bazalova, M; Qu, B; Loo, B; Maxim, P; Hardemark, B; Hynning, E

2014-01-01

Purpose: We evaluated the effect of very high-energy electron (VHEE) beam parameters on the planning of a lung cancer case by means of Monte Carlo simulations. Methods: We simulated VHEE radiotherapy plans using the EGSnrc/BEAMnrc-DOSXYZnrc code. We selected a lung cancer case that was treated with 6MV photon VMAT to be planned with VHEE. We studied the effect of beam energy (80 MeV, 100 MeV, and 120 MeV), number of equidistant beams (16 or 32), and beamlets sizes (3 mm, 5 mm or 7 mm) on PTV coverage, sparing of organs at risk (OARs) and dose conformity. Inverse-planning optimization was performed in a research version of RayStation (RaySearch Laboratories AB) using identical objective functions and constraints for all VHEE plans. Results: Similar PTV coverage and dose conformity was achieved by all the VHEE plans. The 100 MeV and 120 MeV VHEE plans were equivalent amongst them and were superior to the 80 MeV plan in terms of OARs sparing. The effect of using 16 or 32 equidistant beams was a mean difference in average dose of 2.4% (0%–7.7%) between the two plans. The use of 3 mm beamlet size systematically reduced the dose to all the OARs. Based on these results we selected the 100MeV-16beams-3mm-beamlet-size plan to compare it against VMAT. The selected VHEE plan was more conformal than VMAT and improved OAR sparing (heart and trachea received 125% and 177% lower dose, respectively) especially in the low-dose region. Conclusion: We determined the VHEE beam parameters that maximized the OAR dose sparing and dose conformity of the actually delivered VMAT plan of a lung cancer case. The selected parameters could be used for the planning of other treatment sites with similar size, shape, and location. For larger targets, a larger beamlet size might be used without significantly increasing the dose. B Palma: None. M Bazalova: None. B Hardemark: Employee, RaySearch Americas. E Hynning: Employee, RaySearch Americas. B Qu: None. B Loo Jr.: Research support, Ray

Development of electron beam flue gas treatment technology

International Nuclear Information System (INIS)

Tokunaga, Okihiro; Namba, Hideki; Tanaka, Tadashi; Ogura, Yoshimi; Doi, Yoshitake; Aoki, Shinji; Izutsu, Masahiro.

1995-01-01

Smoke treatment system making use of electron beam irradiation made it possible to simultaneously eliminate SOx and NOn from exhaust gas. The fundamental study of the system was started in the seventies and at present, its application in practical use is under way. A pilot plant for the smoke treatment system was constructed in cooperation of Chubu Electric Power Company, Inc., Japan Atomic Energy Research Institute and Ebara Corporation and several tests with the actual exhaust gas were conducted during the period, Oct. 1992-Dec. 1993 and the treatment efficiency and the control capacity of this system was confirmed to be so high as the conventional systems and many engineering data were obtained. A high treatment efficiency (>94% for desulfurization and >80% for denitrification) was obtainable by choosing the optimum irradiation amount of electron beam and the optimum temperature of gas to treat. And this system was found superior from a financial aspect to the conventional smoke treatment system. (M.N.)

SU-F-T-501: Dosimetric Comparison of Single Arc-Per-Beam and Two Arc-Per-Beam VMAT Optimization in the Monaco Treatment Planning System

Energy Technology Data Exchange (ETDEWEB)

Kalet, A; Cao, N; Meyer, J; Dempsey, C [University of Washington Medical Center, Seattle, WA (United States); Seattle Cancer Care Alliance, Seattle, WA (United States); Richardson, H [Seattle Cancer Care Alliance, Seattle, WA (United States)

2016-06-15

Purpose: The purpose of this study was to evaluate the dosimetric and practical effects of the Monaco treatment planning system “max arcs-per-beam” optimization parameter in pelvic radiotherapy treatments. Methods: A total of 17 previously treated patients were selected for this study with a range of pelvic disease site including prostate(9), bladder(1), uterus(3), rectum(3), and cervix(1). For each patient, two plans were generated, one using a arc-per-beam setting of ‘1’ and another with setting of ‘2’. The setting allows the optimizer to add a gantry direction change, creating multiple arc passes per beam sequence. Volumes and constraints established from the initial clinical treatments were used for planning. All constraints and dose coverage objects were kept the same between plans, and all plans were normalized to 99.7% to ensure 100% of the PTV received 95% of the prescription dose. We evaluated the PTV conformity index, homogeneity index, total monitor units, number of control points, and various dose volume histogram (DVH) points for statistical comparison (alpha=0.05). Results: We found for the 10 complex shaped target volumes (small central volumes with extending bilateral ‘arms’ to cover nodal regions) that the use of 2 arcs-per-beam achieved significantly lower average DVH values for the bladder V20 (p=0.036) and rectum V30 (p=0.001) while still meeting the high dose target constraints. DVH values for the simpler, more spherical PTVs were not found significantly different. Additionally, we found a beam delivery time reduction of approximately 25%. Conclusion: In summary, the dosimetric benefit, while moderate, was improved over a 1 arc-per-beam setting for complex PTVs, and equivalent in other cases. The overall reduced delivery time suggests that the use of multiple arcs-per-beam could lead to reduced patient on table time, increased clinical throughput, and reduced medical physics quality assurance effort.

A Monte Carlo pencil beam scanning model for proton treatment plan simulation using GATE/GEANT4

Energy Technology Data Exchange (ETDEWEB)

Grevillot, L; Freud, N; Sarrut, D [Universite de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Universite Lyon 1, Centre Leon Berard, Lyon (France); Bertrand, D; Dessy, F, E-mail: loic.grevillot@creatis.insa-lyon.fr [IBA, B-1348, Louvain-la Neuve (Belgium)

2011-08-21

This work proposes a generic method for modeling scanned ion beam delivery systems, without simulation of the treatment nozzle and based exclusively on beam data library (BDL) measurements required for treatment planning systems (TPS). To this aim, new tools dedicated to treatment plan simulation were implemented in the Gate Monte Carlo platform. The method was applied to a dedicated nozzle from IBA for proton pencil beam scanning delivery. Optical and energy parameters of the system were modeled using a set of proton depth-dose profiles and spot sizes measured at 27 therapeutic energies. For further validation of the beam model, specific 2D and 3D plans were produced and then measured with appropriate dosimetric tools. Dose contributions from secondary particles produced by nuclear interactions were also investigated using field size factor experiments. Pristine Bragg peaks were reproduced with 0.7 mm range and 0.2 mm spot size accuracy. A 32 cm range spread-out Bragg peak with 10 cm modulation was reproduced with 0.8 mm range accuracy and a maximum point-to-point dose difference of less than 2%. A 2D test pattern consisting of a combination of homogeneous and high-gradient dose regions passed a 2%/2 mm gamma index comparison for 97% of the points. In conclusion, the generic modeling method proposed for scanned ion beam delivery systems was applicable to an IBA proton therapy system. The key advantage of the method is that it only requires BDL measurements of the system. The validation tests performed so far demonstrated that the beam model achieves clinical performance, paving the way for further studies toward TPS benchmarking. The method involves new sources that are available in the new Gate release V6.1 and could be further applied to other particle therapy systems delivering protons or other types of ions like carbon.

Electron beam gaseous pollutants treatment

International Nuclear Information System (INIS)

Chmielewski, A.G.

1999-01-01

Emission of gaseous pollutants, mostly during combustion of fossil fuels, creates a threat to the environment. New, economical technologies are needed for flue gas treatment. A physico-chemical basis of the process using electron beam for the simultaneous removal of sulfur and nitrogen oxides and volatile organic compounds are presented in this report. Development of the process and its upscaling has been discussed. (author)

Effects of electron beam parameters and velocity spread on radio frequency output of a photonic band gap cavity gyrotron oscillator

Energy Technology Data Exchange (ETDEWEB)

Singh, Ashutosh, E-mail: asingh.rs.ece@iitbhu.ac.in [Faculty of Physical Sciences, Institute of Natural Sciences and Humanities, Shri Ramswaroop Memorial University, Lucknow-Deva Road, Uttar Pradesh 225003 (India); Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Jain, P. K. [Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2015-09-15

In this paper, the effects of electron beam parameters and velocity spread on the RF behavior of a metallic photonic band gap (PBG) cavity gyrotron operating at 35 GHz with TE{sub 041}–like mode have been theoretically demonstrated. PBG cavity is used here to achieve a single mode operation of the overmoded cavity. The nonlinear time-dependent multimode analysis has been used to observe the beam-wave interaction behavior of the PBG cavity gyrotron, and a commercially available PIC code “CST Particle Studio” has been reconfigured to obtain 3D simulation results in order to validate the analytical values. The output power for this typical PBG gyrotron has been obtained ∼108 kW with ∼15.5% efficiency in a well confined TE{sub 041}–like mode, while all other competing modes have significantly low values of power output. The output power and efficiency of a gyrotron depend highly on the electron beam parameters and velocity spread. The influence of several electron beam parameters, e.g., beam voltage, beam current, beam velocity pitch factor, and DC magnetic field, on the PBG gyrotron operations has been investigated. This study would be helpful in optimising the electron beam parameters and estimating accurate RF output power of the high frequency PBG cavity based gyrotron oscillators.

Beam-beam effects for the PEP-II B Factory

International Nuclear Information System (INIS)

Furman, M.A.; Eden, J.R.

1993-05-01

We present a summary of a fairly extensive study of beam-beam issues that arise in the design of PEP-II. Most of these studies are carried out with ''strong-strong'' multiparticle tracking simulations. We focus on: choice of nominal beam-beam parameter, strength of the parasitic collisions, injection issues, performance and tradeoffs with unequal beam-beam parameters. We comment only briefly on beam lifetime. We conclude that: the beams are sufficiently well separated so that the parasitic collisions are effectively weak; that small inequalities in the beam-beam parameters may imply more comfortable performance margins; and that vertical injection with vertical beam separation is more comfortable than horizontal

Pulsed dye laser treatment of rosacea using a novel 15 mm diameter treatment beam.

Science.gov (United States)

Bernstein, Eric F; Schomacker, Kevin; Paranjape, Amit; Jones, Christopher J

2018-04-10

The pulsed-dye laser has been used to treat facial redness and rosacea for decades. Recent advances in dye laser technology enable 50% higher output energies supporting 50% larger treatment areas, and beam-diameters up to 15 mm with clinically-relevant fluences. In this study, we investigate this novel pulsed-dye laser using a 15 mm diameter beam for treatment of rosacea. Twenty subjects with erythemato-telangiectatic rosacea were enrolled in the study. A total of 4 monthly treatments were administered, first treating linear vessels with a 3 × 10 mm elliptical beam, then diffuse redness with a 15-mm diameter circular beam. Blinded assessment of digital, cross-polarized photographs taken 2 months following the last treatment was performed using an 11-point clearance scale. Nineteen subjects completed the study. Blinded reviewers correctly identified baseline photos in 55 out of the total of 57 images (96.5%). The blinded reviewers scored 17 of the 19 subjects with an improvement greater than 40%, and 11 of the 19 subjects greater than 50%. The average improvement was 53.9%. Side effects were limited to mild edema, mild to moderate erythema, and mild to moderate bruising. This study demonstrates that a newly designed pulsed-dye laser having a novel 15-mm diameter treatment beam improves the appearance of rosacea with a favorable safety profile. Lasers Surg. Med. 9999:1-5, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Beam loading effects for two-beam ring

International Nuclear Information System (INIS)

Wang Lanfa; Lin Yuzheng; Tong Dechun

1999-01-01

An analytic treatment of multi-bunch potential well distortion for a two-beam storage ring is presented. The longitudinal wake effects are separated into: the mode loss, the synchrotron tune shift (both due to potential well distortion) and the coherent multi-bunch coupling. Here, only the first two effects are studied. Resulting simple analytic formulas describe the mode loss and the synchrotron tune shift experienced by a given bunch within the two-beam, as a function of the high order mode's parameters. One can get immediately a simple quantitative answer in term of the mode loss and the synchrotron tune shift experienced by each bunch from these formulas, so the authors can know how to modify the existing configuration of parasitic cavity resonance (via frequency tuning) so that the resulting potential well distortion effects are minimized. When the RF cavities are symmetrically distributed about the interaction points, the two beams will have same beam loading effects, so the authors can compensate the phase shift of the two beam using the same method as in one beam case

Electron Beam Treatment Plant for Textile Dyeing Wastewater

International Nuclear Information System (INIS)

Han, Bumsoo; Kim, Yuri; Choi, Jangseung; Ahn, Sangjun

2006-01-01

High positive effect of electron-beam treatment involved into the process of wastewater purification is now well established. The most effective for the purpose seem to be combine methods including both electron beam and any conventional treatment stages, i.e., under conditions when some synergistic effects can take place. Daegu Dyeing Industrial Complex (DDIC) includes about hundred factories occupying the area of 600,000m 2 with 13,000 employees in total. The production requires high consumption of water (90,000m 3 /day), steam, and electric power, being characterized by large amount of highly colored industrial wastewater. Because of increase in productivity and increased assortment of dyes and other chemicals, substantial necessity appears in re-equipment of purification facilities by application of efficient methods of wastewater treatment

Interplay effects in proton scanning for lung: a 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters

International Nuclear Information System (INIS)

Dowdell, S; Grassberger, C; Sharp, G C; Paganetti, H

2013-01-01

Relative motion between a tumor and a scanning proton beam results in a degradation of the dose distribution (interplay effect). This study investigates the relationship between beam scanning parameters and the interplay effect, with the goal of finding parameters that minimize interplay. 4D Monte Carlo simulations of pencil beam scanning proton therapy treatments were performed using the 4DCT geometry of five lung cancer patients of varying tumor size (50.4–167.1 cc) and motion amplitude (2.9–30.1 mm). Treatments were planned assuming delivery in 35 × 2.5 Gy(RBE) fractions. The spot size, time to change the beam energy (τ es ), time required for magnet settling (τ ss ), initial breathing phase, spot spacing, scanning direction, scanning speed, beam current and patient breathing period were varied for each of the five patients. Simulations were performed for a single fraction and an approximation of conventional fractionation. For the patients considered, the interplay effect could not be predicted using the superior–inferior motion amplitude alone. Larger spot sizes (σ ∼ 9–16 mm) were less susceptible to interplay, giving an equivalent uniform dose (EUD) of 99.0 ± 4.4% (1 standard deviation) in a single fraction compared to 86.1 ± 13.1% for smaller spots (σ ∼ 2–4 mm). The smaller spot sizes gave EUD values as low as 65.3% of the prescription dose in a single fraction. Reducing the spot spacing improved the target dose homogeneity. The initial breathing phase can have a significant effect on the interplay, particularly for shorter delivery times. No clear benefit was evident when scanning either parallel or perpendicular to the predominant axis of motion. Longer breathing periods decreased the EUD. In general, longer delivery times led to lower interplay effects. Conventional fractionation showed significant improvement in terms of interplay, giving a EUD of at least 84.7% and 100.0% of the prescription dose for the small and larger spot sizes

Interplay effects in proton scanning for lung: a 4D Monte Carlo study assessing the impact of tumor and beam delivery parameters.

Science.gov (United States)

Dowdell, S; Grassberger, C; Sharp, G C; Paganetti, H

2013-06-21

Relative motion between a tumor and a scanning proton beam results in a degradation of the dose distribution (interplay effect). This study investigates the relationship between beam scanning parameters and the interplay effect, with the goal of finding parameters that minimize interplay. 4D Monte Carlo simulations of pencil beam scanning proton therapy treatments were performed using the 4DCT geometry of five lung cancer patients of varying tumor size (50.4-167.1 cc) and motion amplitude (2.9-30.1 mm). Treatments were planned assuming delivery in 35 × 2.5 Gy(RBE) fractions. The spot size, time to change the beam energy (τes), time required for magnet settling (τss), initial breathing phase, spot spacing, scanning direction, scanning speed, beam current and patient breathing period were varied for each of the five patients. Simulations were performed for a single fraction and an approximation of conventional fractionation. For the patients considered, the interplay effect could not be predicted using the superior-inferior motion amplitude alone. Larger spot sizes (σ ~ 9-16 mm) were less susceptible to interplay, giving an equivalent uniform dose (EUD) of 99.0 ± 4.4% (1 standard deviation) in a single fraction compared to 86.1 ± 13.1% for smaller spots (σ ~ 2-4 mm). The smaller spot sizes gave EUD values as low as 65.3% of the prescription dose in a single fraction. Reducing the spot spacing improved the target dose homogeneity. The initial breathing phase can have a significant effect on the interplay, particularly for shorter delivery times. No clear benefit was evident when scanning either parallel or perpendicular to the predominant axis of motion. Longer breathing periods decreased the EUD. In general, longer delivery times led to lower interplay effects. Conventional fractionation showed significant improvement in terms of interplay, giving a EUD of at least 84.7% and 100.0% of the prescription dose for the small and larger spot sizes respectively. The

SU-G-TeP4-09: Development of a Plan Data Aggregator for Time Efficient Physics Second-Checks of Machine Parameters for External Beam Treatment Plans

Energy Technology Data Exchange (ETDEWEB)

Belley, M; Schmidt, M; Knutson, N [Rhode Island Hospital, Providence RI (United States); University of Rhode Island, Kingston, RI (United States); Price, M [Rhode Island Hospital, Providence RI (United States); University of Rhode Island, Kingston, RI (United States); Alpert Medical School of Brown University, Providence, RI (United States)

2016-06-15

Purpose: Physics second-checks for external beam radiation therapy are performed, in-part, to verify that the machine parameters in the Record-and-Verify (R&V) system that will ultimately be sent to the LINAC exactly match the values initially calculated by the Treatment Planning System (TPS). While performing the second-check, a large portion of the physicists’ time is spent navigating and arranging display windows to locate and compare the relevant numerical values (MLC position, collimator rotation, field size, MU, etc.). Here, we describe the development of a software tool that guides the physicist by aggregating and succinctly displaying machine parameter data relevant to the physics second-check process. Methods: A data retrieval software tool was developed using Python to aggregate data and generate a list of machine parameters that are commonly verified during the physics second-check process. This software tool imported values from (i) the TPS RT Plan DICOM file and (ii) the MOSAIQ (R&V) Structured Query Language (SQL) database. The machine parameters aggregated for this study included: MLC positions, X&Y jaw positions, collimator rotation, gantry rotation, MU, dose rate, wedges and accessories, cumulative dose, energy, machine name, couch angle, and more. Results: A GUI interface was developed to generate a side-by-side display of the aggregated machine parameter values for each field, and presented to the physicist for direct visual comparison. This software tool was tested for 3D conformal, static IMRT, sliding window IMRT, and VMAT treatment plans. Conclusion: This software tool facilitated the data collection process needed in order for the physicist to conduct a second-check, thus yielding an optimized second-check workflow that was both more user friendly and time-efficient. Utilizing this software tool, the physicist was able to spend less time searching through the TPS PDF plan document and the R&V system and focus the second-check efforts on

E-beam treatment of trichloroethylene-air mixtures: products and rates

International Nuclear Information System (INIS)

Mill, Theodore; Minggong Su; Yao, C.C.D.; Matthews, S.M.; Wang, F.T.S.

1997-01-01

Electron beam (E-beam) treatment of 3000 ppmv trichloroethylene (TCE) vapor in dry and wet air led to rapid, nearly quantitative, conversion of TCE to dichloroacetyl chloride, plus small amounts of phosgene. Higher E-beam dose, up to 110 kGy, led to oxidation of the initial products to CO, CO 2 , HCl and Cl 2 . The results parallel results found for photo- and Cl-atom initiated oxidation of TCE vapor, and are accounted for by an efficient Cl-atom chain oxidation. Lack of effect of 28,000 ppmv water vapor (90% RH) on rates or products reflects a very high efficiency for the Cl-atom chain oxidation and the very slow reaction of vapor phase water with acyl halides. Irradiation experiments conducted with TCE dissolved in aerated and deaerated water at 10 and 300 ppm showed marked differences in radiolytic products from those found in the vapor phase. A preliminary cost estimate indicates that E-beam treatment of TCE vapor is very competitive with conventional activated carbon treatment and catalytic oxidation. (author)

Pilot test of flue gas treatment by electron beam

International Nuclear Information System (INIS)

Tokunaga, Okihiro

1995-01-01

The development of the technology of the desulfurization and denitration for flue gas by using electron beam was started in Japan in 1970s, and since then, the development research for putting it to practical use and the basic research on the subjects which must be resolved for promoting the practical use have been advanced. Based on these results, the verifying test using a pilot scale plant was carried out from 1991 to 1994 for the treatment of coal-burning flue gas, municipal waste-burning flue gas and highway tunnel exhaust gas. The operation of the pilot plant was already finished, and the conceptual design of a practical scale plant based on the results and the assessment of the economical efficiency were performed. As for the coal-burning flue gas treatment by using electron beam, the basic test, the pilot test and the conceptual design of a practical scale plant and the assessment of the economical efficiency are reported. As for the municipal waste-burning flue gas treatment by using electron beam, the basic test and the pilot test are reported. Also the pilot test on the denitration of exhaust gas in highway tunnels in reported. In Poland, the pilot test on the treatment of flue gas in coal-burning thermal power stations is carried out. In Germany, the technical development for cleaning the air contaminated by volatile organic compounds by electron beam irradiation is advanced. (K.I.)

Signal processing for longitudinal parameters of the Tevatron beam

International Nuclear Information System (INIS)

Pordes, S.; Crisp, J.; Fellenz, B.; Flora, R.; Para, A.; Tollestrup, A.V.

2005-01-01

We describe the system known as the Tevatron SBD [1] which is used to provide information on the longitudinal parameters of coalesced beam bunches in the Tevatron. The system has been upgraded over the past year with a new digitizer and improved software. The quantities provided for each proton and antiproton bunch include the intensity, the longitudinal bunch profile, the timing of the bunch with respect to the low-level RF, the momentum spread and the longitudinal emittance. The system is capable of 2 Hz operation and is run at 1 Hz

Parameters of a supershort avalanche electron beam generated in atmospheric-pressure air

International Nuclear Information System (INIS)

Tarasenko, V. F.

2011-01-01

Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ∼5 × 10 10 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eU m , where U m is the maximum gap voltage, is relatively small.

Parameters of a supershort avalanche electron beam generated in atmospheric-pressure air

Science.gov (United States)

Tarasenko, V. F.

2011-05-01

Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ˜5 × 1010 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eU m , where U m is the maximum gap voltage, is relatively small.

Parameters That Effect the Interfacial Stresses in Fibre Reinforced Plastic Laminates Strengthened Rc Beams

Directory of Open Access Journals (Sweden)

Barış Sayın

2010-01-01

Full Text Available The use of externally bonded fiber-reinforced plastic (FRP laminates for strengthening of reinforced concrete beams has become an effective method. This method has been used because of the advantages of FRP materials such as their high strength-to-weight ratio, good corrosion resistance, and versatility in coping with different sectional shapes and corners. Many studies on this theme have been carried out since the early 1900s. In this study, interfacial stresses of reinforced concrete beams strengthened with FRP effect the parameters will be studied as experimental and numerical. Adhesives used in the beams applied to FRP's thickness, adhesive type and the state of the concrete surface, produced experimental samples are exposed to the bending effect will be studied as a comparative. Afterwards, by using the ANSYS® WB finite element program to model and analyze RC beams by externally bonding FRP will be carried out. Adhesive thickness, adhesive type, the concrete surface will be performed by entering the parameters for analysis of stress can be obtained as a result. Thus, the analytical expressions of stress and normal stress equations will establish should be modified. Finite element analysis and experimental results will be compared, compatibility investigated, the results and recommendations presented by the study be completed.

Monte Carlo Simulation of a Linear Accelerator and Electron Beam Parameters Used in Radiotherapy

Directory of Open Access Journals (Sweden)

Mohammad Taghi Bahreyni Toossi

2009-06-01

Full Text Available Introduction: In recent decades, several Monte Carlo codes have been introduced for research and medical applications. These methods provide both accurate and detailed calculation of particle transport from linear accelerators. The main drawback of Monte Carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. Material and Methods: In this study, the MCNP-4C Monte Carlo code was used to simulate the electron beams generated by a Neptun 10 PC linear accelerator. The depth dose curves and related parameters to depth dose and beam profiles were calculated for 6, 8 and 10 MeV electron beams with different field sizes and these data were compared with the corresponding measured values. The actual dosimetry was performed by employing a Welhofer-Scanditronix dose scanning system, semiconductor detectors and ionization chambers. Results: The result showed good agreement (better than 2% between calculated and measured depth doses and lateral dose profiles for all energies in different field sizes. Also good agreements were achieved between calculated and measured related electron beam parameters such as E0, Rq, Rp and R50. Conclusion: The simulated model of the linac developed in this study is capable of computing electron beam data in a water phantom for different field sizes and the resulting data can be used to predict the dose distributions in other complex geometries.

A Monte Carlo-based treatment-planning tool for ion beam therapy

CERN Document Server

Böhlen, T T; Dosanjh, M; Ferrari, A; Haberer, T; Parodi, K; Patera, V; Mairan, A

2013-01-01

Ion beam therapy, as an emerging radiation therapy modality, requires continuous efforts to develop and improve tools for patient treatment planning (TP) and research applications. Dose and fluence computation algorithms using the Monte Carlo (MC) technique have served for decades as reference tools for accurate dose computations for radiotherapy. In this work, a novel MC-based treatment-planning (MCTP) tool for ion beam therapy using the pencil beam scanning technique is presented. It allows single-field and simultaneous multiple-fields optimization for realistic patient treatment conditions and for dosimetric quality assurance for irradiation conditions at state-of-the-art ion beam therapy facilities. It employs iterative procedures that allow for the optimization of absorbed dose and relative biological effectiveness (RBE)-weighted dose using radiobiological input tables generated by external RBE models. Using a re-implementation of the local effect model (LEM), theMCTP tool is able to perform TP studies u...

Treatment of absolute painful glaucoma with dynamic arcs using novalis shaped beam radiosurgery

International Nuclear Information System (INIS)

Gonzalez-Olhovich, Irene; Celis, Miguel Angel; Larraga-Gutierrez, Jose; Lopez-Ayala, Temuchino; Suarez-Campos, Jose; Garcia-Garduno, Amanda; Herrera-Gomez, Leopoldo; Hernandez-Bojorquez, Mariana B.Sc.

2006-01-01

Purpose: We assessed the effect of shaped beam conformal stereotactic radiosurgery (SRS) in 1 patient with chronic painful glaucoma in one eye refractory to medical treatment. Methods and Materials: Left eye ciliary body was targeted at 18 Gy (90% isodose curve) with a dedicated linear accelerator (Novalis, BrainLAB, Germany) SRS. Interval follow-up was performed weekly for the first month, and every 2 months until 1 year was completed with clinical examinations and intraocular pressure (IOP) measurements. Results: Ocular pain resolved at 6 weeks after SRS treatment. IOP decreased and normalized at 1 year. Conclusions: We present a case in which SRS appears to be an effective treatment of chronic refractory painful glaucoma. Further Phase I studies are needed to know the best parameters for radiation dose, tolerance of organs at risk, and pathophysiologic effects

SU-E-T-778: Use of the 2D MatriXX Detector for Measuring Scanned Ion Beam Parameters

Energy Technology Data Exchange (ETDEWEB)

Anvar, M Varasteh; Monaco, V; Sacchi, R; Guarachi, L Fanola; Cirio, R [Istituto Nazionale di Fisica Nucleare (INFN), Division of Turin, TO (Italy); University of Torino, Turin, TO (Italy); Giordanengo, S; Marchetto, F; Vignati, A [Istituto Nazionale di Fisica Nucleare (INFN), Division of Turin, TO (Italy); Donetti, M [Istituto Nazionale di Fisica Nucleare (INFN), Division of Turin, TO (Italy); Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, PV (Italy); Ciocca, M; Panizza, D [Centro Nazionale di Adroterapia Oncologica (CNAO), Pavia, PV (Italy)

2015-06-15

Purpose: The quality assurance (QA) procedure has to check the most relevant beam parameters to ensure the delivery of the correct dose to patients. Film dosimetry, which is commonly used for scanned ion beam QA, does not provide immediate results. The purpose of this work is to answer whether, for scanned ion beam therapy, film dosimetry can be replaced with the 2D MatriXX detector as a real-time tool. Methods: MatriXX, equipped with 32×32 parallel plate ion-chambers, is a commercial device intended for pre-treatment verification of conventional radiation therapy.The MatriXX, placed at the isocenter, and GAFCHROMIC films, positioned on the MatriXX entrance, were exposed to 131.44 MeV proton and 221.45 MeV/u Carbon-ion beams.The OmniPro-I’mRT software, applied for the data taking of MatriXX, gives the possibility of acquiring consecutive snapshots. Using the NI LabVIEW, the data from snapshots were logged as text files for further analysis. Radiochromic films were scanned with EPSON scanner and analyzed using software programs developed in-house for comparative purposes. Results: The field dose uniformity, flatness, beam position and beam width were investigated. The field flatness for the region covering 6×6 cm{sup 2} square field was found to be better than 2%. The relative standard deviations, expected to be constant over 2×2, 4×4 and 6×6 pixels from MatriXX measurement gives a uniformity of 1.5% in good agreement with the film results.The beam center position is determined with a resolution better than 200 µm for Carbon and less than 100 µm for proton beam.The FWHM determination for a beam wider than 10 mm is satisfactory, whilst for smaller beams the determination is uncertain. Conclusion: Precise beam position and fast 2D dose distribution can be determined in real-time using MatriXX detector. The results show that MatriXX is quick and accurate enough to be used in charged-particle therapy QA.

Long-range and head-on beam-beam compensation studies in RHIC with lessons for the LHC

International Nuclear Information System (INIS)

Fischer, W.; Luo, Y.; Abreu, N.; Calaga, R.; Montag, C.; Robert-Demolaize, G.; Dorda, U.; Koutchouk, J.-P.; Sterbini, G.; Zimmermann, F.; Kim, H.-J.; Sen, T.; Shiltsev, V.; Valishev, A.; Qiang, J.; Kabel, A.

2009-01-01

Long-range as well as head-on beam-beam effects are expected to limit the LHC performance with design parameters. They are also important consideration for the LHC upgrades. To mitigate long-range effects, current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. Electron lenses were proposed for both RHIC and the LHC to reduce the head-on beam-beam effect. We present the experimental long-range beam-beam program at RHIC and report on head-on compensations studies based on simulations

Total skin electron therapy treatment verification: Monte Carlo simulation and beam characteristics of large non-standard electron fields

International Nuclear Information System (INIS)

Pavon, Ester Carrasco; Sanchez-Doblado, Francisco; Leal, Antonio; Capote, Roberto; Lagares, Juan Ignacio; Perucha, Maria; Arrans, Rafael

2003-01-01

Total skin electron therapy (TSET) is a complex technique which requires non-standard measurements and dosimetric procedures. This paper investigates an essential first step towards TSET Monte Carlo (MC) verification. The non-standard 6 MeV 40 x 40 cm 2 electron beam at a source to surface distance (SSD) of 100 cm as well as its horizontal projection behind a polymethylmethacrylate (PMMA) screen to SSD = 380 cm were evaluated. The EGS4 OMEGA-BEAM code package running on a Linux home made 47 PCs cluster was used for the MC simulations. Percentage depth-dose curves and profiles were calculated and measured experimentally for the 40 x 40 cm 2 field at both SSD = 100 cm and patient surface SSD = 380 cm. The output factor (OF) between the reference 40 x 40 cm 2 open field and its horizontal projection as TSET beam at SSD = 380 cm was also measured for comparison with MC results. The accuracy of the simulated beam was validated by the good agreement to within 2% between measured relative dose distributions, including the beam characteristic parameters (R 50 , R 80 , R 100 , R p , E 0 ) and the MC calculated results. The energy spectrum, fluence and angular distribution at different stages of the beam (at SSD = 100 cm, at SSD = 364.2 cm, behind the PMMA beam spoiler screen and at treatment surface SSD = 380 cm) were derived from MC simulations. Results showed a final decrease in mean energy of almost 56% from the exit window to the treatment surface. A broader angular distribution (FWHM of the angular distribution increased from 13deg at SSD 100 cm to more than 30deg at the treatment surface) was fully attributable to the PMMA beam spoiler screen. OF calculations and measurements agreed to less than 1%. The effect of changing the electron energy cut-off from 0.7 MeV to 0.521 MeV and air density fluctuations in the bunker which could affect the MC results were shown to have a negligible impact on the beam fluence distributions. Results proved the applicability of using MC

Beam angle selection for intensity-modulated radiotherapy (IMRT) treatment of unresectable pancreatic cancer: are noncoplanar beam angles necessary?

Science.gov (United States)

Chang, D S; Bartlett, G K; Das, I J; Cardenes, H R

2013-09-01

External beam radiation therapy with concurrent chemotherapy (CRT) is widely used for the treatment of unresectable pancreatic cancer. Noncoplanar (NCP) 3D conformal radiotherapy (3DCRT) and coplanar (CP) IMRT have been reported to lower the radiation dose to organs at risk (OARs). The purpose of this article is to examine the utility of noncoplanar beam angles in IMRT for the management of pancreatic cancer. Sixteen patients who were treated with CRT for unresectable adenocarcinoma of the pancreatic head or neck were re-planned using CP and NCP beams in 3DCRT and IMRT with the Varian Eclipse treatment planning system. Compared to CP IMRT, NCP IMRT had similar target coverage with slightly increased maximum point dose, 5,799 versus 5,775 cGy (p = 0.008). NCP IMRT resulted in lower mean kidney dose, 787 versus 1,210 cGy (p kidney dose, but did not improve other dose-volume criteria. The use of NCP beam angles is preferred only in patients with risk factors for treatment-related kidney dysfunction.

A double expansion method for the frequency response of finite-length beams with periodic parameters

Science.gov (United States)

Ying, Z. G.; Ni, Y. Q.

2017-03-01

A double expansion method for the frequency response of finite-length beams with periodic distribution parameters is proposed. The vibration response of the beam with spatial periodic parameters under harmonic excitations is studied. The frequency response of the periodic beam is the function of parametric period and then can be expressed by the series with the product of periodic and non-periodic functions. The procedure of the double expansion method includes the following two main steps: first, the frequency response function and periodic parameters are expanded by using identical periodic functions based on the extension of the Floquet-Bloch theorem, and the period-parametric differential equation for the frequency response is converted into a series of linear differential equations with constant coefficients; second, the solutions to the linear differential equations are expanded by using modal functions which satisfy the boundary conditions, and the linear differential equations are converted into algebraic equations according to the Galerkin method. The expansion coefficients are obtained by solving the algebraic equations and then the frequency response function is finally determined. The proposed double expansion method can uncouple the effects of the periodic expansion and modal expansion so that the expansion terms are determined respectively. The modal number considered in the second expansion can be reduced remarkably in comparison with the direct expansion method. The proposed double expansion method can be extended and applied to the other structures with periodic distribution parameters for dynamics analysis. Numerical results on the frequency response of the finite-length periodic beam with various parametric wave numbers and wave amplitude ratios are given to illustrate the effective application of the proposed method and the new frequency response characteristics, including the parameter-excited modal resonance, doubling-peak frequency response

Studies on post weld heat treatment of dissimilar aluminum alloys by laser beam welding technique

Science.gov (United States)

Srinivas, B.; Krishna, N. Murali; Cheepu, Muralimohan; Sivaprasad, K.; Muthupandi, V.

2018-03-01

The present study mainly focuses on post weld heat treatment (PWHT) of AA5083 and AA6061 alloys by joining these using laser beam welding at three different laser power and two different beam spot sizes and three different welding speeds. Effects of these parameters on microstructural and mechanical properties like hardness, tensile strength were studied at PWHT condition and significant changes had been observed. The PWHT used was artificial aging technique. The microstructural observations revealed that there was a appreciable changes were taken place in the grain size. The microhardness observations proven that the change in the hardness profile in AA6061 was appreciable than in the AA5083. The tensile strength of 246 MPa was recorded as highest. The fractured surfaces observed are predominantly ductile in nature.

Precision Beam Parameter Monitoring in a Measurement of the Weak Mixing Angle in Moeller Scattering

Energy Technology Data Exchange (ETDEWEB)

Cooke, M.S.

2005-04-11

A precision measurement of the parity nonconserving left-right asymmetry, A{sub LR}, in Moeller scattering (e{sup -}e{sup -} {yields} e{sup -}e{sup -}) is currently in progress at the Stanford Linear Accelerator Center (SLAC). This experiment, labeled SLAC-E158, scatters longitudinally polarized electrons off atomic electrons in an unpolarized hydrogen target at a Q{sup 2} of 0.03 (GeV/c){sup 2}. The asymmetry, which is the fractional difference in the scattering cross-sections, measures the effective pseudo-scalar weak neutral current coupling, g{sub ee}, governing Moeller scattering. This quantity is in turn proportional to (1/4 - sin{sup 2} {theta}{sub w}), where {theta}{sub w} is the electroweak mixing angle. The goal is to measure the asymmetry to a precision of 1 x 10{sup -8} which corresponds to {delta}(sin{sup 2} {theta}{sub w}) {approx} 0.0007. Since A{sub LR} is a function of the cross-sections, and the cross-sections depend on the beam parameters, the desired precision of A{sub LR} places stringent requirements on the beam parameters. This paper investigates the requirements on the beam parameters and discusses the means by which they are monitored and accounted for.

Luminosity Loss due to Beam Distortion and the Beam-Beam Instability

CERN Document Server

Wu, Juhao; Raubenheimer, Tor O; Seryi, Andrei; Sramek, Christopher K

2005-01-01

In a linear collider, sources of emittance dilution such as transverse wakefields or dispersive errors will couple the vertical phase space to the longitudinal position within the beam (the so-called ‘banana effect'). When the Intersection Point (IP) disruption parameter is large, these beam distortions will be amplified by a single bunch kink instability which will lead to luminosity loss. We study this phenomena both analytically using linear theory and via numerical simulation. In particular, we examine the dependence of the luminosity loss on the wavelength of the beam distortions and the disruption parameter. This analysis may prove useful when optimizing the vertical disruption parameter for luminosity operation with given beam distortions.

Radiation-beam technologies of structural materials treatment

International Nuclear Information System (INIS)

Kalin, B.A.

2001-01-01

Considered in the paper are the most advanced and prospective radiation-beam technologies (RBT) for treatment of structural materials, as applied to modifying the structural-phase state in the surface layers of half-finished products and articles with the purpose to improve their service properties. Ion-beam, plasma, and ion-plasma, as well as the technologies based on the use of concentrated fluxes of energy, generated by laser radiation, high-power pulsed electron and ion beams, and high-temperature pulsed plasma fluxes are analysed. As applied to improvement of the corrosion and erosion resistance, breaking strength, friction and wear resistance, and crack resistance, the directions of the choice and the use of RBT have been considered for changes of the surface layer state by applying covers and films, and by a change of the surface topography (relief), surface structure and defects, and the element composition and phase state of materials [ru

Demonstration test of electron beam flue gas treatment pilot plant of a coal fired thermal power station

International Nuclear Information System (INIS)

Doi, Yoshitaka; Hayashi, Kazuaki; Izutsu, Masahiro; Watanabe, Shigeharu; Namba, Hideki; Tokunaga, Okihiro; Hashimoto, Shoji; Tanaka, Tadashi; Ogura, Yoshimi.

1995-01-01

The Japan Atomic Energy Research Institute, Chubu Electric Power Company and Ebara Corporation jointly constructed a pilot plant for electron beam flue gas treatment (dry process) capable of treating 12,000 m 3 /h (NTP) of flue gas from a coal fired boiler, at Shin-Nagoya Thermal Power Station, Chubu Electric Power Company. Various tests carried out at the plant over a period extending one year verified the followings. By appropriately controlling parameters such as electron beam dosage, flue gas temperature, and ammonia stoichiometric amount, highly efficient simultaneous SO 2 and NOx removal from flue gas was achieved under all gas conditions, equal to or more efficient than that by the highest level conventional treatment. The operation of the pilot plant was stable and trouble-free over a long term, and the operation and the process was easy to operate and control. By-products (ammonium sulfate and ammonium nitrate) produced by the flue gas treatment were proven to have superior quality, equivalent to that of market-available nitrogen fertilizers. These by-products had been registered as by-product nitrogen fertilizers. (author)

Intermediate Megavoltage Photon Beams for Improved Lung Cancer Treatments.

Directory of Open Access Journals (Sweden)

Ying Zhang

Full Text Available The goal of this study is to evaluate the effects of intermediate megavoltage (3-MV photon beams on SBRT lung cancer treatments. To start with, a 3-MV virtual beam was commissioned on a commercial treatment planning system based on Monte Carlo simulations. Three optimized plans (6-MV, 3-MV and dual energy of 3- and 6-MV were generated for 31 lung cancer patients with identical beam configuration and optimization constraints for each patient. Dosimetric metrics were evaluated and compared among the three plans. Overall, planned dose conformity was comparable among three plans for all 31 patients. For 21 thin patients with average short effective path length (< 10 cm, the 3-MV plans showed better target coverage and homogeneity with dose spillage index R50% = 4.68±0.83 and homogeneity index = 1.26±0.06, as compared to 4.95±1.01 and 1.31±0.08 in the 6-MV plans (p < 0.001. Correspondingly, the average/maximum reductions of lung volumes receiving 20 Gy (V20Gy, 5 Gy (V5Gy, and mean lung dose (MLD were 7%/20%, 9%/30% and 5%/10%, respectively in the 3-MV plans (p < 0.05. The doses to 5% volumes of the cord, esophagus, trachea and heart were reduced by 9.0%, 10.6%, 11.4% and 7.4%, respectively (p < 0.05. For 10 thick patients, dual energy plans can bring dosimetric benefits with comparable target coverage, integral dose and reduced dose to the critical structures, as compared to the 6-MV plans. In conclusion, our study indicated that 3-MV photon beams have potential dosimetric benefits in treating lung tumors in terms of improved tumor coverage and reduced doses to the adjacent critical structures, in comparison to 6-MV photon beams. Intermediate megavoltage photon beams (< 6-MV may be considered and added into current treatment approaches to reduce the adjacent normal tissue doses while maintaining sufficient tumor dose coverage in lung cancer radiotherapy.

The electron beam characteristics of energies up to 20 MeV and comparison of electron parameters of linear accelerators

International Nuclear Information System (INIS)

Awada, M.; Elleithy, M.A.; ElWihady, G.F.; Mostafa, K.A.

2005-01-01

The electron beams characteristics studded for the energies 4-20 MeV of Varian 23 EX ,experimental results are presented and compared with the published data. The CADD curves are measured for all energies and carried out the PDD of different applicator sizes ,that compared with the PDD of in the BJR. The quality beam parameters are determined from the CADD curves and calculated the yielded parameters of the corresponding electron energies which compared with the published data of other accelerators and theoretical Monte-Carlo calculation. The beam profiles are measured at different depths to construct the isodose distribution

Beam-beam effect and luminosity in SPEAR

International Nuclear Information System (INIS)

Wiedemann, H.

1980-07-01

Measurements performed at SPEAR have been discussed and scaling laws for the maximum luminosity and the maximum linear tune shift parameter with energy are shown. There are two distinct regimes, one below 2 GeV where the linear tune shift parameter scales like xi/sub y/ approx. E 2 4 and the other regime where this parameter is constant xi/sub y/ approx. = 0.05 to 0.06. In the lower energy regime the limit is reached when the vertical beam size is blown up to the acceptance of the storage ring. A significant (< 10%) horizontal beam blow up is not observed and the value of the horizontal linear tune shift parameter xi/sub x/ does not seem to be related to the beam-beam limit

The Through Process Simulation of Mold filling, Solidification, and Heat Treatment of the Al Alloy Bending Beam Low-pressure Casting

International Nuclear Information System (INIS)

Yin, Yajun; Guo, Zhao; Wang, Huan; Liao, Dunming; Chen, Tao; Zhou, Jianxin

2015-01-01

The research on the simulation for the through process of low-pressure casting and heat treatment is conducive to combine information technology and advanced casting technology, which will help to predict the defects and mechanical properties of the castings in the through process. In this paper, we focus on the simulation for through process of low-pressure casting and heat treatment of ZL114A Bending beam. Firstly, we analyzethe distribution of the shrinkage and porosities in filling and solidification process, and simulate the distribution of stress and strain in the late solidification of casting. Then, the numerical simulation of heat treatment process for ZL114A Bending beam is realized according to the heat treatment parameters and the corresponding simulation results of temperature field, stress, strain, and aging performance are given. Finally, we verify that simulation platform for the through process of low-pressure casting and heat treatment can serve the production practice perfectly and provide technical guidance and process optimization for the through process of low-pressure casting and heat treatment. (paper)

Effect of basic physical parameters to control plasma meniscus and beam halo formation in negative ion sources

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Nishioka, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2013-09-14

Our previous study shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources: the negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. In this article, the detail physics of the plasma meniscus and beam halo formation is investigated with two-dimensional particle-in-cell simulation. It is shown that the basic physical parameters such as the H{sup −} extraction voltage and the effective electron confinement time significantly affect the formation of the plasma meniscus and the resultant beam halo since the penetration of electric field for negative ion extraction depends on these physical parameters. Especially, the electron confinement time depends on the characteristic time of electron escape along the magnetic field as well as the characteristic time of electron diffusion across the magnetic field. The plasma meniscus penetrates deeply into the source plasma region when the effective electron confinement time is short. In this case, the curvature of the plasma meniscus becomes large, and consequently the fraction of the beam halo increases.

Effect of basic physical parameters to control plasma meniscus and beam halo formation in negative ion sources

International Nuclear Information System (INIS)

Miyamoto, K.; Okuda, S.; Nishioka, S.; Hatayama, A.

2013-01-01

Our previous study shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources: the negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. In this article, the detail physics of the plasma meniscus and beam halo formation is investigated with two-dimensional particle-in-cell simulation. It is shown that the basic physical parameters such as the H − extraction voltage and the effective electron confinement time significantly affect the formation of the plasma meniscus and the resultant beam halo since the penetration of electric field for negative ion extraction depends on these physical parameters. Especially, the electron confinement time depends on the characteristic time of electron escape along the magnetic field as well as the characteristic time of electron diffusion across the magnetic field. The plasma meniscus penetrates deeply into the source plasma region when the effective electron confinement time is short. In this case, the curvature of the plasma meniscus becomes large, and consequently the fraction of the beam halo increases

SU-E-T-254: Optimization of GATE and PHITS Monte Carlo Code Parameters for Uniform Scanning Proton Beam Based On Simulation with FLUKA General-Purpose Code

Energy Technology Data Exchange (ETDEWEB)

Kurosu, K [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Department of Medical Physics ' Engineering, Osaka University Graduate School of Medicine, Osaka (Japan); Takashina, M; Koizumi, M [Department of Medical Physics ' Engineering, Osaka University Graduate School of Medicine, Osaka (Japan); Das, I; Moskvin, V [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)

2014-06-01

Purpose: Monte Carlo codes are becoming important tools for proton beam dosimetry. However, the relationships between the customizing parameters and percentage depth dose (PDD) of GATE and PHITS codes have not been reported which are studied for PDD and proton range compared to the FLUKA code and the experimental data. Methods: The beam delivery system of the Indiana University Health Proton Therapy Center was modeled for the uniform scanning beam in FLUKA and transferred identically into GATE and PHITS. This computational model was built from the blue print and validated with the commissioning data. Three parameters evaluated are the maximum step size, cut off energy and physical and transport model. The dependence of the PDDs on the customizing parameters was compared with the published results of previous studies. Results: The optimal parameters for the simulation of the whole beam delivery system were defined by referring to the calculation results obtained with each parameter. Although the PDDs from FLUKA and the experimental data show a good agreement, those of GATE and PHITS obtained with our optimal parameters show a minor discrepancy. The measured proton range R90 was 269.37 mm, compared to the calculated range of 269.63 mm, 268.96 mm, and 270.85 mm with FLUKA, GATE and PHITS, respectively. Conclusion: We evaluated the dependence of the results for PDDs obtained with GATE and PHITS Monte Carlo generalpurpose codes on the customizing parameters by using the whole computational model of the treatment nozzle. The optimal parameters for the simulation were then defined by referring to the calculation results. The physical model, particle transport mechanics and the different geometrybased descriptions need accurate customization in three simulation codes to agree with experimental data for artifact-free Monte Carlo simulation. This study was supported by Grants-in Aid for Cancer Research (H22-3rd Term Cancer Control-General-043) from the Ministry of Health

WE-D-BRB-02: Proton Treatment Planning and Beam Optimization

Energy Technology Data Exchange (ETDEWEB)

Pankuch, M. [Northwestern Medicine Proton Center (United States)

2016-06-15

The goal of this session is to review the physics of proton therapy, treatment planning techniques, and the use of volumetric imaging in proton therapy. The course material covers the physics of proton interaction with matter and physical characteristics of clinical proton beams. It will provide information on proton delivery systems and beam delivery techniques for double scattering (DS), uniform scanning (US), and pencil beam scanning (PBS). The session covers the treatment planning strategies used in DS, US, and PBS for various anatomical sites, methods to address uncertainties in proton therapy and uncertainty mitigation to generate robust treatment plans. It introduces the audience to the current status of image guided proton therapy and clinical applications of CBCT for proton therapy. It outlines the importance of volumetric imaging in proton therapy. Learning Objectives: Gain knowledge in proton therapy physics, and treatment planning for proton therapy including intensity modulated proton therapy. The current state of volumetric image guidance equipment in proton therapy. Clinical applications of CBCT and its advantage over orthogonal imaging for proton therapy. B. Teo, B.K Teo had received travel funds from IBA in 2015.

Measurement of the longitudinal parameters of an electron beam in a storage ring

International Nuclear Information System (INIS)

Krinsky, S.

1989-01-01

We discuss the determination of the longitudinal parameters of a bunched beam of electrons or positrons circulating in a storage ring. From the analysis of the beam current observed at a fixed azimuthal location, one can learn much about the longitudinal behavior. We present an elementary analysis of the time-dependence of the current. In particular, we discuss the determination of the average current, bunch length, synchrotron oscillation frequency, and the coherent synchrotron oscillation modes associated with longitudinal instabilities. A brief discussion is also given of the incoherent synchrotron oscillations, or Schottky noise. We review the electromagnetic field traveling with a charge in uniform motion, and introduce some of the most common devices used to detect this field: capacitive pick-up, stripline monitor, and DC beam current transformer. Our paper is organized as follows: We discuss the analysis of the time-dependence of the beam current. Then, the measurement of the current is considered. Finally, we describe some measurements of energy spread and bunch lengthening made recently at SLAC on the SLC damping ring. 12 refs., 6 figs

Improvement in Dissolution of Cotton Pulp with Ionic liquid by the Electron Beam Treatment

International Nuclear Information System (INIS)

Lee, Won Sil; Jung, Wong Gi; Sung, Yong Joo

2013-01-01

Electron beam treatment was applied for improving dissolution of cotton pulp with ionic liquids. Two ionic liquids, 1-allyl-3-methylimidazolium chloride ([Amim]Cl]: AC) and 1,3-dimethylimidzolium methlphosphite ([Dmim][(MeO)(H)PO2]: Me) were used for this experiment. Treatment with electron beams up to dose of 400 kGy resulted in the increase of hot water extract and alkali extract of cotton pulp and the great reduction in the molecular weight of cellulose. For the dissolution of cotton pulp with two ionic liquids, the electron beam treated samples showed faster dissolution. The dissolved cellulose with Me ionic liquid were regenerated with Acetonitrile and the structure of regenerated cellulose showed distinct difference depending on the electron beam treatment. Those results provide the electron beam pre-treatment could be applied as an energy efficient and environmentally benign method to increase the dissolution of cotton pulp with ionic liquids

Adaptive Model Predictive Vibration Control of a Cantilever Beam with Real-Time Parameter Estimation

Directory of Open Access Journals (Sweden)

Gergely Takács

2014-01-01

Full Text Available This paper presents an adaptive-predictive vibration control system using extended Kalman filtering for the joint estimation of system states and model parameters. A fixed-free cantilever beam equipped with piezoceramic actuators serves as a test platform to validate the proposed control strategy. Deflection readings taken at the end of the beam have been used to reconstruct the position and velocity information for a second-order state-space model. In addition to the states, the dynamic system has been augmented by the unknown model parameters: stiffness, damping constant, and a voltage/force conversion constant, characterizing the actuating effect of the piezoceramic transducers. The states and parameters of this augmented system have been estimated in real time, using the hybrid extended Kalman filter. The estimated model parameters have been applied to define the continuous state-space model of the vibrating system, which in turn is discretized for the predictive controller. The model predictive control algorithm generates state predictions and dual-mode quadratic cost prediction matrices based on the updated discrete state-space models. The resulting cost function is then minimized using quadratic programming to find the sequence of optimal but constrained control inputs. The proposed active vibration control system is implemented and evaluated experimentally to investigate the viability of the control method.

Geometric Parameters Estimation and Calibration in Cone-Beam Micro-CT

Directory of Open Access Journals (Sweden)

Jintao Zhao

2015-09-01

Full Text Available The quality of Computed Tomography (CT images crucially depends on the precise knowledge of the scanner geometry. Therefore, it is necessary to estimate and calibrate the misalignments before image acquisition. In this paper, a Two-Piece-Ball (TPB phantom is used to estimate a set of parameters that describe the geometry of a cone-beam CT system. Only multiple projections of the TPB phantom at one position are required, which can avoid the rotation errors when acquiring multi-angle projections. Also, a corresponding algorithm is derived. The performance of the method is evaluated through simulation and experimental data. The results demonstrated that the proposed method is valid and easy to implement. Furthermore, the experimental results from the Micro-CT system demonstrate the ability to reduce artifacts and improve image quality through geometric parameter calibration.

Exploring the relationship between structurally defined geometrical parameters of reinforced concrete beams and the thermal comfort on indoor environment

DEFF Research Database (Denmark)

Lee, Daniel Sang-Hoon; Naboni, Emanuele

2017-01-01

mass effect (and the implication on thermal comfort) and the given geometrical parameters of exposed soffit reinforced concrete beams are explored. The geometrical parameters of the beams are initially defined in means of structural optimisation. The beams consist of flange and web in likeness of T...... the resultant heat exchange behaviour, and the implication on thermal comfort indoor environment. However, the current paper presents the thermal mass characteristics of one geometrical type. The study is based on results derived from computational fluid dynamics (CFD) analysis, where Rhino 3D is used......The paper presents a research exploring the thermal mass effect of reinforced concrete beams with structurally optimised geometrical forms. Fully exposed concrete soffits in architectural contexts create more than just visual impacts on the indoor climate through their possible interferences...

Optimum field size and choice of isodose lines in electron beam treatment

International Nuclear Information System (INIS)

Das, Indra J.; Cheng, Chee W.; Healey, Glenn A.

1995-01-01

Purpose: A method is provided for the optimum field size and the choice of isodose line for the dose prescription in electron beam therapy. Methods and Materials: Electron beam dose uniformity was defined in terms of target coverage factor (TCF) which is an index of dose coverage of a given treatment volume. The TCF was studied with respect to the field size, the beam energy, and the isodose level for prescription from the measured data for various accelerators. The effect of the TCF on air gap between electron applicator/cone and the surface was investigated. Electron beams from scattering foil and scanned beam units were analyzed for the target coverage. Results: A mathematical method is provided to optimize a field size for target coverage by a given isodose line in terms of TCF which is strongly dependent on the type of accelerator and the design of the collimator. For a given type of collimating system, the TCF does not depend on the type of electron beam production (scattering foil or swept scanned beam). Selection of isodose line for dose prescription is very critical for the value of the TCF and the dose coverage. The TCF is inversely proportional to the isodose value selected for the treatment and nearly linear with field size and beam energy. Air gap between applicator and the surface reduces the dose uniformity. Tertiary collimator moderately improves the lateral coverage for high energy beams. Conclusions: To adequately cover the target volume in electron beam treatment, lateral and depth coverage should be considered. The coverage at depth is strongly dependent on the choice of isodose line or beam normalization. If the dose prescription is at d max (i.e., the 100% isodose line is selected), the choice of beam energy is not critical for depth coverage since d max is nearly independent of energy for smaller fields. The 100% isodose line should not be chosen for treatment because of the significant constriction of this isodose line and inadequate

Physical parameters and biological effects of the LVR-15 epithermal neutron beam

International Nuclear Information System (INIS)

Burian, J.; Marek, M.; Rejchrt, J.; Viererbl, L.; Gambarini, G.; Mares, V.; Vanossi, E.; Judas, L.

2006-01-01

Monitoring of the physical and biological properties of the epithermal neutron beam constructed at the multipurpose LVR-15 nuclear reactor for NCT therapy of brain tumors showed that its physical and biological properties are stable in time and independent on an ad hoc reconfiguration of the reactor core before its therapeutic use. Physical parameters were monitored by measurement of the neutron spectrum, neutron profile, fast neutron kerma rate in tissue and photon absorbed dose, the gel dosimetry was used with the group of standard measurement methods. The RBE of the beam, as evaluated by 3 different biological models, including mouse intestine crypt regeneration assay, germinative zones of the immature rat brain and C6 glioma cells in culture, ranged from 1.70 to 1.99. (author)

Studies of toxic metals removal in industrial wastewater after electron-beam treatment

International Nuclear Information System (INIS)

Ribeiro, Marcia Almeida

2002-01-01

The Advanced Oxidation Process, using electron-beam, have been studied by scientific community due to its capacity to mineralize the toxic organic compound from highly reactive radical's formation. The electron-beam treatment process has been adopted by several countries for organic compounds removal and to effluents and sewers biological degradation. In this work, studies of metals removal in the simulated aqueous solutions and in the actual industrial effluents were carried out, using electron-beam treatment. The effluents samples were collected at ETE/SABESP (Governmental Wastewater Treatment Plant) in Suzano, SP city. The sampling was outlined at three distinctive sites: Industrial Receiver Unit, Medium Bar, and Final Effluent. The effluents samples were irradiated using different irradiation doses (20, 50, 100, 200 and 500 kGy). The removal behavior of metals Ca, CI, S, P, K, Al, Fe, As, Ni, Cr, Zn, Si, Co, Mn, As, Se, Cd, Hg and Pb was verified. The elements determination was accomplished with the x-ray fluorescence (WD-XRFS) technique using Fundamental Parameters method and thin film samples. The elements Fe, Zn, Cr and Co presented a removal > 99% to 200 kGy of irradiation dose in industrial effluent. At the same dose, P, Al and Si presented a removal of 81.8%, 97.6% and 98.7%, respectively. Ca and S were removed more than 80% at 20 kGy and Na, CI and K did not presented any degree of removal. As, Se, Cd, Hg and Pb removal was studied in the simulated aqueous solutions and industrial effluents with scavengers addition (EDTA and HCOONa). The elements As and Hg presented a removal of 92% and 99%, respectively, with HCOONa, at 500 kGy irradiation dose. The Se presented a 96.5% removal at same irradiation dose without scavengers addition. The removal of Cd and Pb did not give a significant removal, once all of the assay were carried out in the oxidant medium. (author)

Beam parameters observations during the second high pile-up collisions fill in 2011

CERN Document Server

Trad, G; Buffat, X; Calaga, R; Cornelis, K; Herr, W; Jacquet, D; Papotti, G; Schaumann, M; Venturini Delsolaro, W

2012-01-01

On the 25th of October 2011, a physics fill( Fill nr 2252) was dedicated to providing ATLAS & CMS with high pile-up collisions. A peak pile-up (number of inelastic interactions per crossing) μ of almost 35 was achieved. Part of the test was also to bring the pile-up to values < 0.5 and this was achieved by separating the beams in steps. The Head-On collisions were restored after each IP separation to study its effects. In this note observations of the beam parameters evolution (bunch current, emittances and length) are presented. Some conclusions are drawn and suggestions for future MDs are discussed.

Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

Energy Technology Data Exchange (ETDEWEB)

Klintstroem, Eva; Smedby, Oerjan [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); UHL County Council of Oestergoetland, Department of Radiology, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Moreno, Rodrigo [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Brismar, Torkel B. [KUS Huddinge, Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Stockholm (Sweden)

2014-02-15

Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference. Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained. The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini. The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT. (orig.)

Implementation of depolarization due to beam-beam effects in the beam-beam interaction simulation tool GUINEA-PIG++

Science.gov (United States)

Rimbault, C.; Le Meur, G.; Blampuy, F.; Bambade, P.; Schulte, D.

2009-12-01

Depolarization is a new feature in the beam-beam simulation tool GUINEA-PIG++ (GP++). The results of this simulation are studied and compared with another beam-beam simulation tool, CAIN, considering different beam parameters for the International Linear Collider (ILC) with a centre-of-mass energy of 500 GeV.

Electron beam treatment removes both sulphur and nitrogen oxides

International Nuclear Information System (INIS)

Kawamura, K.; Miller, G.A.

1985-01-01

The Ebara Corporation in Japan has developed an electron beam flue gas treatment (e-beam fgt) process. The process offers the following features: simultaneous removal of SO 2 and NOsub(x); a dry process which involves no slurry recycling, no sludge disposal, and no gas reheating; turndown and load following capabilities with a minimum of process control; SO 2 and NOsub(x) are converted into saleable fertiliser. The demonstration plant is described. (author)

Calculation of electron-beam induced displacement in thin films by using parameter-reduced formulas

Energy Technology Data Exchange (ETDEWEB)

Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Chen, Di [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States); Wang, Qingyu; Li, Zhongyu [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States)

2017-03-01

Based on the Mott cross sections of relativistic electron collisions with atoms, we calculate displacement creation by electron beams of arbitrary energies (up to 100 MeV) in thin films of arbitrary atomic numbers (up to Z = 90). In a comparison with Mont Carlo full damage cascade simulations, we find that total number of displacements in a film can be accurately estimated as the product of average displacements created per collision and average collision numbers in the film. To calculate average displacements per electron-atom collision, energy transfer from Mott cross section is combined with NRT model. To calculate collision numbers, mean deflection angles and multi-scattering theory are combined to extract collision number dependence on film thickness. For each key parameter, parameter-reduced formulas are obtained from data fitting. The fitting formulas provide a quick and accurate method to estimate radiation damage caused by electron beams.

Towards an objective evaluation of tolerances for beam modeling in a treatment planning system

International Nuclear Information System (INIS)

Rangel, A; Ploquin, N; Kay, I; Dunscombe, P

2007-01-01

The performance of a convolution/superposition based treatment planning system depends on the ability of the dose calculation algorithm to accurately account for physical interactions taking place in the tissue, key components of the linac head and on the accuracy of the photon beam model. Generally the user has little or no control over the performance of the dose calculation algorithm but is responsible for the accuracy of the beam model within the constraints imposed by the system. This study explores the dosimetric impact of limitations in photon beam modeling accuracy on complex 3D clinical treatment plans. A total of 70 photon beam models was created in the Pinnacle(TM) treatment planning system. Two of the models served as references for 6 MV and 15 MV beams, while the rest were created by perturbing the reference models in order to produce specific deviations in specific regions of the calculated dose profiles (central axis and transverse). The beam models were then used to generate 3D plans on seven CT data sets each for four different treatment sites (breast and conformal prostate, lung and brain). The equivalent uniform doses (EUD) of the targets and the principal organs at risk (OARs) of all plans (∼1000) were calculated and compared to the EUDs delivered by the reference beam models. In general, accurate dosimetry of the target is most greatly compromised by poor modeling of the central axis depth dose and the horns, while the EUDs of the OARs exhibited the greatest sensitivity to beam width accuracy. Based on the results of this analysis we suggest a set of tolerances to be met during commissioning of the beam models in a treatment planning system that are consistent in terms of clinical outcomes as predicted by the EUD

Current status of electron beam treatment of flue gas in China

International Nuclear Information System (INIS)

Wang Zhiguang

2006-01-01

Fossil resource especially coal will remain the main energy resource in China over the next 3 ∼4 decades. Pollution of flue gas from fossil power station is one problem being desiderated to solve since 1990's. Electron beam treatment of flue gas as an advanced technique has been developed and used by some institutes and industries in China. The current status of flue gas treatment using electron beam and the development of electron accelerator in China are reviewed. (author)

A practical method of modeling a treatment couch using cone-beam computed tomography for intensity-modulated radiation therapy and RapidArc treatment delivery

Energy Technology Data Exchange (ETDEWEB)

Aldosary, Ghada, E-mail: ghada.aldosary@mail.mcgill.ca [Medical Physics Unit, McGill University Health Centre, Montreal, Quebec (Canada); Nobah, Ahmad; Al-Zorkani, Faisal [Biomedical Physics Department, King Faisal Specialist Hospital and Research Center, Riyadh (Saudi Arabia); Devic, Slobodan [Department of Radiation Oncology, Jewish General Hospital, McGill University, Montreal, Quebec (Canada); Moftah, Belal [Medical Physics Unit, McGill University Health Centre, Montreal, Quebec (Canada); Biomedical Physics Department, King Faisal Specialist Hospital and Research Center, Riyadh (Saudi Arabia)

2015-01-01

The effect of a treatment couch on dose perturbation is not always fully considered in intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). In the course of inverse planning radiotherapy techniques, beam parameter optimization may change in the absence of the couch, causing errors in the calculated dose distributions. Although modern treatment planning systems (TPS) include data for the treatment couch components, they are not manufactured identically. Thus, variations in their Hounsfield unit (HU) values may exist. Moreover, a radiotherapy facility may wish to have a third-party custom tabletop installed that is not included by the TPS vendor. This study demonstrates a practical and simple method of acquiring reliable computed tomography (CT) data for the treatment couch and shows how the absorbed dose calculated with the modeled treatment couch can differ from that with the default treatment couch found in the TPS. We also experimentally verified that neglecting to incorporate the treatment couch completely in the treatment planning process might result in dose differences of up to 9.5% and 7.3% for 4-MV and 10-MV photon beams, respectively. Furthermore, 20 RapidArc and IMRT cases were used to quantify the change in calculated dose distributions caused by using either the default or modeled couch. From 2-dimensional (2D) ionization chamber array measurements, we observed large dose distribution differences between the measurements and calculations when the couch was omitted that varied according to the planning technique and anatomic site. Thus, incorporating the treatment couch in the dose calculation phase of treatment planning significantly decreases dose calculation errors.

A One-Step Cone-Beam CT-Enabled Planning-to-Treatment Model for Palliative Radiotherapy-From Development to Implementation

International Nuclear Information System (INIS)

Wong, Rebecca K.S.; Letourneau, Daniel; Varma, Anita; Bissonnette, Jean Pierre; Fitzpatrick, David; Grabarz, Daniel; Elder, Christine; Martin, Melanie; Bezjak, Andrea; Panzarella, Tony; Gospodarowicz, Mary; Jaffray, David A.

2012-01-01

Purpose: To develop a cone-beam computed tomography (CT)–enabled one-step simulation-to-treatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry (≤2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CT–enabled planning process at the treatment unit. Phase C evaluated the online cone-beam CT–enabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n = 9) established the adequacy of cone-beam CT images for target definition. Phase B (n = 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% ± 11% and 97% ± 4%, respectively. The oncologist’s decision to accept the plan under a time-pressured environment remained of high quality, with the cone-beam CT–generated treatment plan delivering at least 90% of the prescribed dose to 100% ± 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CT–generated treatment plan delivered at least 90% and at least 95% of dose to 98% ± 2% and 97% ± 5% of the PCT PTV, respectively. The mean time for the online planning and treatment process was 32.7 ± 4.0 minutes. Patient satisfaction was high, with a trend for superior satisfaction with the cone-beam CT–enabled process. Conclusions: The cone-beam CT�

A One-Step Cone-Beam CT-Enabled Planning-to-Treatment Model for Palliative Radiotherapy-From Development to Implementation

Energy Technology Data Exchange (ETDEWEB)

Wong, Rebecca K.S., E-mail: rebecca.wong@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Letourneau, Daniel; Varma, Anita [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Bissonnette, Jean Pierre; Fitzpatrick, David; Grabarz, Daniel; Elder, Christine [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Martin, Melanie; Bezjak, Andrea [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Panzarella, Tony [Department of Biostatistics, Princess Margaret Hospital, Toronto, Ontario (Canada); Gospodarowicz, Mary [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada)

2012-11-01

Purpose: To develop a cone-beam computed tomography (CT)-enabled one-step simulation-to-treatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry ({<=}2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CT-enabled planning process at the treatment unit. Phase C evaluated the online cone-beam CT-enabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n = 9) established the adequacy of cone-beam CT images for target definition. Phase B (n = 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% {+-} 11% and 97% {+-} 4%, respectively. The oncologist's decision to accept the plan under a time-pressured environment remained of high quality, with the cone-beam CT-generated treatment plan delivering at least 90% of the prescribed dose to 100% {+-} 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CT-generated treatment plan delivered at least 90% and at least 95% of dose to 98% {+-} 2% and 97% {+-} 5% of the PCT PTV, respectively. The mean time for the online planning and treatment process was 32.7 {+-} 4.0 minutes. Patient satisfaction was high, with a trend for superior satisfaction with the cone-beam CT-enabled process. Conclusions: The cone-beam

Laser beam diameter for port wine stain treatment

NARCIS (Netherlands)

Keijzer, M.; Pickering, J. W.; van Gemert, M. J.

1991-01-01

Optimal port wine stain treatment requires the selective absorption of light by the ectatic blood vessels. We investigated whether deeper blood vessels can be coagulated, without damaging other cutaneous structures, by varying the laser beam diameter. The penetration of the light was simulated with

The study of PDMS surface treatment and it's applications by using proton beam

International Nuclear Information System (INIS)

Baek, J. Y.; Kim, J. Y.; Kwon, K. H.; Park, J. Y.

2007-04-01

PDMS(Polydimethylsiloxane) is mainly used as a material to do lab on a chip for biochemical analysis. PDMS has many applicability at the Bio-Technology(BT) field, because it is flexible, biocompatible and has good oxygen permeability. In this study, we have investigated to physical and chemical changes of PDMS surface by proton beam radiation conditions. The used kind of ion were Ar and N, beam energy was 30keV, 60keV, 80keV, total fluence was 1E10 to 1E16 [ions/cm 2 ]. PDMS membrane was produced as 150 μm thick on the 3' silicon wafer. We inquired into physical and chemical changes up to beam radiation conditions through the investigate the change of surface roughness by AFM(Atomic Force Microscope), the change of surface morphology by SEM(Scanning Electron Microscope) and the change of chemical composition by FT-IR(Fourier Transform Infrared Raman spectroscopy) and XPS(X-ray Photoelectron Spectroscopy). From these basic data to we set up the proton beam radiation conditions to secure metal layer and PDMS adhesion. This enables to produce the electrode at the PDMS material lab on a chip. From now on, we'll investigate the cell patterning possibility after carry out of cell culture with mouse fibroblast at PDMS surface what is surface modification by using of proton beam radiation and apply this to produce lab on a chip. Physical property: Surface roughness of PDMS membrane was observed using AFM, after exposure of proton beam on it. The roughness increased as the power level of proton beam increase. This phenomena was caused by the kinetic energy of particle. Chemical property: Long term observation was conducted on the contact angles of the samples made by the proton beam exposure or oxygen plasma treatment; the hydrophilicity was found to be stronger in the samples made by the proton beam exposure. We found the reason of this was the destruction of polymer chains by proton beam. Feasibility of Through-hole: Considering that comparatively high level energy beam

Controls and Beam Diagnostics for Therapy-Accelerators

CERN Document Server

Eickhoff, H

2000-01-01

During the last four years GSI has developed a new procedure for cancer treatment by means of the intensity controlled rasterscan-method. This method includes active variations of beam parameters during the treatment session and the integration of 'on-line' PET monitoring. Starting in 1997 several patients have been successfully treated within this GSI experimental cancer treatment program; within this program about 350 patients shall be treated in the next 5 years. The developments and experiences of this program accompanied by intensive discussions with the medical community led to a proposal for a hospital based light ion accelerator facility for the clinic in Heidelberg. An essential part for patients treatments is the measurement of the beam properties within acceptance and constancy tests and especially for the rasterscan method during the treatment sessions. The presented description of the accelerator controls and beam diagnostic devices mainly covers the requests for the active scanning method, which...

Simulation of beam-splitter made of metamaterials with angle spatial distribution of constitutive parameters based on transformation optics for THz frequency range

International Nuclear Information System (INIS)

Gurvitz, E A; Vozianova, A V; Khodzitsky, M K

2014-01-01

New approach to design beam splitter on basis of the transformation optics using angle constitutive parameters distribution of medium was proposed. The beam splitter was numerically simulated by COMSOL Multiphysics for terahertz frequency range. The numerical simulations were carried out for ideal and reduced constitutive parameters of medium for the case of TM plane wave

Proton beam therapy how protons are revolutionizing cancer treatment

CERN Document Server

Yajnik, Santosh

2013-01-01

Proton beam therapy is an emerging technology with promise of revolutionizing the treatment of cancer. While nearly half of all patients diagnosed with cancer in the US receive radiation therapy, the majority is delivered via electron accelerators, where photons are used to irradiate cancerous tissue. Because of the physical properties of photon beams, photons may deposit energy along their entire path length through the body. On the other hand, a proton beam directed at a tumor travels in a straight trajectory towards its target, gives off most of its energy at a defined depth called the Bragg peak, and then stops. While photons often deposit more energy within the healthy tissues of the body than within the cancer itself, protons can deposit most of their cancer-killing energy within the area of the tumor. As a result, in the properly selected patients, proton beam therapy has the ability to improve cure rates by increasing the dose delivered to the tumor and simultaneously reduce side-effects by decreasing...

Scanning-probe-microscopy of polyethylene terephthalate surface treatment by argon ion beam

Energy Technology Data Exchange (ETDEWEB)

Espinoza-Beltran, Francisco [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Sanchez, Isaac C. [Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712 (United States); España-Sánchez, Beatriz L.; Mota-Morales, Josué D.; Carrillo, Salvador; Enríquez-Flores, C.I. [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Poncin-Epaillard, Fabienne, E-mail: epaill@univ-lemans.fr [Institute for Molecules and Materials, UMR CNRS 6283, Av. O. Messiaen, Universitè du Maine, Le Mans 72085 (France); Luna-Barcenas, Gabriel, E-mail: gluna@qro.cinvestav.mx [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico)

2015-11-01

Highlights: • Kelvin-probe-force microscopy helps study of PET surface treated by Ar ion beam. • Ar ion beam surface treatment promotes chain scission and N insertion. • Surface roughness and work function increases as intensity of ion energy increases. • Adhesive force of PET decrease due to the surface changes by ion bombardment. - Abstract: The effect of argon (Ar{sup +}) ion beam treatment on the surface of polyethylene terephthalate (PET) samples was studied by scanning probe microscopy (SPM) and the changes in surface topography were assessed by atomic force microscopy (AFM). Kelvin probe force microscopy (KPFM) sheds light of adhesion force between treated polymer films and a Pt/Cr probe under dry conditions, obtaining the contact potential difference of material. As a result of Ar{sup +} ion bombardment, important surface chemical changes were detected by X-ray photoelectron spectroscopy (XPS) measurements such as chains scission and incorporation of nitrogen species. Ion beam treatment increases the surface roughness from 0.49 ± 0.1 nm to 7.2 ± 0.1 nm and modify the surface potential of PET samples, decreasing the adhesive forces from 12.041 ± 2.1 nN to 5.782 ± 0.06 nN, and producing a slight increase in the electronic work function (Φ{sub e}) from 5.1 V (untreated) to 5.2 V (treated). Ar{sup +} ion beam treatment allows to potentially changing the surface properties of PET, modifying surface adhesion, improving surface chemical changes, wetting properties and surface potential of polymers.

Chromium Waste Treatment from Leather Manufacture Using Electron Beam Radiation Technic

International Nuclear Information System (INIS)

Didiek Herhady, R.; Sukarsono, R.

2007-01-01

Leather manufacture chromium waste treatment using chemical methods have an essential disadvantage, because of the production of the secondary contamination of wastes and separated sediments used by reagents. Therefore, a new technique is needed to solve this problem. The aim of the research to learn the advantages of electron beam radiation for chromium waste treatment. Water radiolysis can be produced by the interaction between electron beam and water or liquid substances. This phenomenon produces many reducing agents and ions that could reduce chromium concentrations in the liquid waste. Ethyl alcohol as a scavenger was added in the waste samples, then the pH of varied from 1, 4, 8 to 12, then were irradiated. Irradiation were done by Electron Beam Machine with dose 15, 25, and 35 kGy. After irradiation, chromium concentration in the samples were analyzed by AAS and UV-vis spectrophotometer. The results had shown that chromium could be reduced by high dose electron beam. The optimum reduction of chromium was achieved at liquid waste pH 8 and irradiation dose 35 kGy. (author)

Electron beam weld parameter set development and cavity cost

International Nuclear Information System (INIS)

John Brawley; John Mammossor; Larry Philips

1997-01-01

Various methods have recently been considered for use in the cost-effective manufacturing of large numbers of niobium cavities. A method commonly assumed to be too expensive is the joining of half cells by electron beam welding (EBW), as has been done with multipurpose EBW equipment for producing small numbers of cavities at accelerator laboratories. The authors have begun to investigate the advantages that would be available if a single-purpose, task-specific EBW processing tool were used to produce cavities in a high-volume commercial-industrial context. For such a tool and context they have sought to define an EBW parameter set that is cost-effective not only in terms of per-cavity production cost, but also in terms of the minimization of quench-producing weld defects. That is, they define cavity cost-effectiveness to include both production and performance costs. For such an EBW parameter set, they have developed a set of ideal characteristics, produced and tested samples and a complete cavity, studied the weld-defect question, and obtained industrial estimates of cavity high-volume production costs. The investigation in ongoing. This paper reports preliminary findings

Analytical treatment of the nonlinear electron cloud effect and the combined effects with beam-beam and space charge nonlinear forces in storage rings

International Nuclear Information System (INIS)

Gao Jie

2009-01-01

In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonlinear electron cloud effect combined with beam-beam and space charge effects, analytically. This analytical treatment is applied to BEPC II. The corresponding analytical expressions developed in this paper are useful both in understanding the physics behind these problems and also in making practical quick hand estimations. (author)

Characteristic parameters analysis on diagnostic X-ray beams for dosemeter calibration

International Nuclear Information System (INIS)

Oliveira, Paulo Marcio Campos de

2008-01-01

Ionizing radiation metrology is the base to achieve reliable dose measurements in ali areas; it is also part of the framework that is established to assure radiation protection procedures in order to avoid or minimize the harmful biological effect that may be caused by ionizing radiation. A well done metrology means the use of reliable instruments that comply with standard performance requirements worldwide accepted. Those instruments are expected to be calibrated by Metrology Laboratories under well defined conditions. The International Electrotechnical Commission (IEC) in Standard 61267 established the reference radiations for medical diagnostic x-ray equipment that are recommended to be used for calibrating dosimetric systems for diagnostic dosimetry. In this work, X-ray beam qualities were established in a Calibration Laboratory and their characteristics were analyzed through the measurement of beam parameters like inherent tube filtration, beam uniformity and field size, energy spectra and peak voltage for additional filtration with 94.425 por cent and 99.999 por cent purity filters. Also, the first half-value layer and the homogeneity coefficient were measured for the three RQR 2, RQR 6 and RQR 10 IEC beam qualities and they were analyzed according to the IEC standard. Air-kerma measurements were carried out with an ionization chamber that had its reliability confirmed through repetition and reproducibility reading tests. In 50 sets of measurements the maximum standard deviation found of 10 successive readings was 0.19 %; the maximum shift of the reading mean value at a fixed geometry condition was 0.80 % with an overall standard deviation of 0.23 %. Results showed that the use of different purity filters did not cause a relevant influence on the beam energy spectra. An ionization chamber was also calibrated against a standard dosimeter in ali implemented reference radiations and the relevant sources of uncertainties were estimated. Calibration could be done

Matching Electron Beams Without Secondary Collimation for Treatment of Extensive Recurrent Chest-Wall Carcinoma

International Nuclear Information System (INIS)

Feygelman, Vladimir; Mandelzweig, Yuri; Baral, Ed

2015-01-01

Matching electron beams without secondary collimators (applicators) were used for treatment of extensive, recurrent chest-wall carcinoma. Due to the wide penumbra of such beams, the homogeneity of the dose distribution at and around the junction point is clinically acceptable and relatively insensitive to positional errors. Specifically, dose around the junction point is homogeneous to within ±4% as calculated from beam profiles, while the positional error of 1 cm leaves this number essentially unchanged. The experimental isodose distribution in an anthropomorphic phantom supports this conclusion. Two electron beams with wide penumbra were used to cover the desired treatment area with satisfactory dose homogeneity. The technique is relatively simple yet clinically useful and can be considered a viable alternative for treatment of extensive chest-wall disease. The steps are suggested to make this technique more universal.

Performance test results of ion beam transport for SST-1 neutral beam injector

Energy Technology Data Exchange (ETDEWEB)

Jana, M R; Mattoo, S K [Institute for Plasma Research Bhat, Gandhinagar-382428, Gujarat (India); Uhlemann, R, E-mail: mukti@ipr.res.i [Forschungszentrum Juelich, Institute fur Energieforschung IEF-4, Plasmaphysik D-52425 Juelich (Germany)

2010-02-01

A neutral beam injector is built at IPR to heat the plasma of SST-1 and its upgrade. It delivers a maximum beam power of 1.7 MW for 55 kV Hydrogen beam or 80 kV Deuterium beam. At lower beam voltage, the delivered power falls to 500 kW at 30 kV Hydrogen beam which is adequate to heat SST-1 plasma ions to {approx} 1 keV. Process of acceleration of ions to the required beam voltage, conversion of ions to neutrals and removal of un-neutralized ions and the beam diagnostic systems occupy a large space. The consequence is that linear extent of the neutral beam injector is at least a few meters. Also, port access provides a very narrow duct. Even a very good injector design and fabrication practices keep beam divergence at a very low but finite value. The result is beam transport becomes an important issue. Since a wide area beam is constructed by hundreds of beam lets, it becomes essential they be focused in such a way that beam transport loss is minimized. Horizontal and vertical focal lengths are two parameters, in addition to beam divergence, which give a description of the beam transport. We have obtained these two parameters for our injector by using beam transport code; making several hundred simulation runs by varying optical parameters of the beam. The selected parameters set has been translated into the engineering features of the extractor grid set of the ion source. Aperture displacement technique is used to secure the horizontal beam focusing at 5.4 m. Combination of both aperture displacement and inclining of two grid halves to {approx} 17 mrad are secured for vertical beam focusing at 7 m from earth grid of the ion source. The gaps between the design, engineered and performance tested values usually arise due to lack of exercising control over fabrication processes or due to inaccuracies in the assumption made in the model calculations of beam optics and beam transport. This has been the case with several injectors, notably with JET injector. To overcome

Treatment of basal cell epithelioma with high energy electron beam

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Y. (Hyogo-ken Cancer Center, Kobe (Japan)); Kumano, M.; Kumano, K.

1981-11-01

Thirty patients with basal cell epithelioma received high energy electron beam therapy. They were irradiated with a dose ranging from 4,800 rad (24 fractions, 35 days) to 12,000 rad (40 fractions, 57 days). Tumors disappeared in all cases. These were no disease-related deaths; in one patient there was recurrence after 2 years. We conclude that radiotherapy with high energy electron beam is very effective in the treatment of basal cell epithelioma.

Use of an INGRES database to implement the beam parameter management at GANIL

International Nuclear Information System (INIS)

Gillette, P.; Lecorche, E.; Lermine, P.; Maugeais, C.; Leboucher, Ch.; Moscatello, M.H.; Pain, P.

1995-01-01

Since the beginning of the operation driven by the new Ganil control system in February 1993, the relational database management system (RDBMS) Ingres has been more and more widely used. The most significant application relying on the RDBMS is the new beam parameter management which has been entirely redesigned. It has been operational since the end of the machine shutdown in July this year. After a short recall of the use of Ingres inside the control system, the organization of the parameter management is presented. Then the database implementation is shown, including the way how the physical aspects of the Ganil tuning have been integrated in such an environment. (author)

Gas flow parameter determination by molecular beam method

International Nuclear Information System (INIS)

Zarvin, A.E.; Sharafutdinov, R.G.

1977-01-01

This paper describes a molecular-beam system intended for studying nonequilibrium processes in supersonic rarefied gas flows. The system represented is a small molecular beam source placed inside the low intensity wind tunnel of the Institute of Thermophysics, Siberian Branch of the USSR Academy of Sciences. The time-of-flight method is used for measuring molecular velocity distribution functions on molecular beam axis. (Auth.)

Assessment of beam stability of high energy and low energy Varian medical linear accelerators

International Nuclear Information System (INIS)

Jayesh, K.; Mohan, R.; Joshi, R.C.; Ganesh, T.; Hegazy, M.; Oubaye, A.J.; AI Idrisi, Maha

2008-01-01

An accurate measurement of the dose delivered to the tumor in external beam radiotherapy is one of the primary responsibilities of a medical physicist. In general, such measurements have been based on the application of a dosimetry protocol and quality assurance procedures. Clinically one must be able to assess the beam quality, flatness and symmetry and variation in the output on daily basis. Flatness and symmetry are the main parameters for determining the pattern of a photon and electron beam produced by linear accelerators. The quality assurance in routine clinical practice of radiotherapy and consequently the treatment-outcome depends definitely on the physical parameters of treatment-delivery. Several recommendations from national and international associations are reported to define the limits for the beam parameters. The review of literature and various reports on quality assurance in radiotherapy show that for flatness, symmetry and output constancy the optimal level of deviation should be within ±3%

Upgrade for the epithermal neutron beam at NRI Rez

International Nuclear Information System (INIS)

Marek, M.; Flibor, S.; Viererbl, L.; Burian, J.; Rejchrt, J.; Klupak, V.; Gambarini, G.; Vanossi, E.

2006-01-01

The epithermal neutron beam facility designed for pre-clinical neutron capture therapy research has been operated at LVR-15 reactor for more than ten years. The construction of the beam filter has been recently modified especially for the shielding quality of the beam shutter to be improved. The parameters of the upgraded beam were calculated with the MCNP code and a new source term for the NCTPLAN treatment planning software was evaluated. The calculated source term was consequently scaled according to the results of measurements in the free beam and in the 50x50x25 cm 3 water phantom. (author)

Development of a golden beam data set for the commissioning of a proton double-scattering system in a pencil-beam dose calculation algorithm

International Nuclear Information System (INIS)

Slopsema, R. L.; Flampouri, S.; Yeung, D.; Li, Z.; Lin, L.; McDonough, J. E.; Palta, J.

2014-01-01

Purpose: The purpose of this investigation is to determine if a single set of beam data, described by a minimal set of equations and fitting variables, can be used to commission different installations of a proton double-scattering system in a commercial pencil-beam dose calculation algorithm. Methods: The beam model parameters required to commission the pencil-beam dose calculation algorithm (virtual and effective SAD, effective source size, and pristine-peak energy spread) are determined for a commercial double-scattering system. These parameters are measured in a first room and parameterized as function of proton energy and nozzle settings by fitting four analytical equations to the measured data. The combination of these equations and fitting values constitutes the golden beam data (GBD). To determine the variation in dose delivery between installations, the same dosimetric properties are measured in two additional rooms at the same facility, as well as in a single room at another facility. The difference between the room-specific measurements and the GBD is evaluated against tolerances that guarantee the 3D dose distribution in each of the rooms matches the GBD-based dose distribution within clinically reasonable limits. The pencil-beam treatment-planning algorithm is commissioned with the GBD. The three-dimensional dose distribution in water is evaluated in the four treatment rooms and compared to the treatment-planning calculated dose distribution. Results: The virtual and effective SAD measurements fall between 226 and 257 cm. The effective source size varies between 2.4 and 6.2 cm for the large-field options, and 1.0 and 2.0 cm for the small-field options. The pristine-peak energy spread decreases from 1.05% at the lowest range to 0.6% at the highest. The virtual SAD as well as the effective source size can be accurately described by a linear relationship as function of the inverse of the residual energy. An additional linear correction term as function of

Development of a golden beam data set for the commissioning of a proton double-scattering system in a pencil-beam dose calculation algorithm

Energy Technology Data Exchange (ETDEWEB)

Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Flampouri, S.; Yeung, D.; Li, Z. [University of Florida Proton Therapy Institute, 2015 North Jefferson Street, Jacksonville, Florida 32205 (United States); Lin, L.; McDonough, J. E. [Department of Radiation Oncology, University of Pennsylvania, 3400 Civic Boulevard, 2326W TRC, PCAM, Philadelphia, Pennsylvania 19104 (United States); Palta, J. [VCU Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298 (United States)

2014-09-15

Purpose: The purpose of this investigation is to determine if a single set of beam data, described by a minimal set of equations and fitting variables, can be used to commission different installations of a proton double-scattering system in a commercial pencil-beam dose calculation algorithm. Methods: The beam model parameters required to commission the pencil-beam dose calculation algorithm (virtual and effective SAD, effective source size, and pristine-peak energy spread) are determined for a commercial double-scattering system. These parameters are measured in a first room and parameterized as function of proton energy and nozzle settings by fitting four analytical equations to the measured data. The combination of these equations and fitting values constitutes the golden beam data (GBD). To determine the variation in dose delivery between installations, the same dosimetric properties are measured in two additional rooms at the same facility, as well as in a single room at another facility. The difference between the room-specific measurements and the GBD is evaluated against tolerances that guarantee the 3D dose distribution in each of the rooms matches the GBD-based dose distribution within clinically reasonable limits. The pencil-beam treatment-planning algorithm is commissioned with the GBD. The three-dimensional dose distribution in water is evaluated in the four treatment rooms and compared to the treatment-planning calculated dose distribution. Results: The virtual and effective SAD measurements fall between 226 and 257 cm. The effective source size varies between 2.4 and 6.2 cm for the large-field options, and 1.0 and 2.0 cm for the small-field options. The pristine-peak energy spread decreases from 1.05% at the lowest range to 0.6% at the highest. The virtual SAD as well as the effective source size can be accurately described by a linear relationship as function of the inverse of the residual energy. An additional linear correction term as function of

Electron beam treatment parameters for control of stored product insects

International Nuclear Information System (INIS)

Cleghorn, D.A.; Nablo, S.V.; Ferro, D.N.; Hagstrum, D.W.

2002-01-01

The fluidized bed process (EBFB) has been evaluated for the disinfestation of cereal grains. The various life stages from egg to adult have been studied on the 225 kV pilot as a function of surface dose. Three of the most common pests were selected: the rice weevil (S. oryzae), the lesser grain borer (R. dominica) and the red flour beetle (T. castaneum). The major challenge to this process lies in those 'protected' life-stages active deeply within the endosperm of the grain kernel. The rice weevil is such an internal feeder in which the larvae develop through several molts during several weeks before pupation and adult emergence. Product velocities up to 2000 m/min have been used for infested hard winter wheat at dose levels up to 1000 Gy. Detailed depth of penetration studies at three life stages of S. oryzae larvae were conducted at 225-700 kV and demonstrated effective mortality at 400 kVx200 Gy. Mortality data are also presented for the radiation labile eggs of these insects as well as the (sterile) adults, which typically lived for several weeks before death. These results are compared with earlier 60 Co gamma-ray studies on these same insects. Based upon these studies, the effectiveness of the fluidized bed process employing self-shielded electron beam equipment for insect control in wheat/rice at sub-kilogray dose levels has been demonstrated

An Influence of 7.5 T Superconducting Wiggler on Beam Parameters of Siberia-2 Storage Ring

International Nuclear Information System (INIS)

Korchuganov, Vladimir; Valentinov, Alexander; Mezentsev, Nikolai

2007-01-01

At present the dedicated synchrotron radiation source Siberia-2 in Kurchatov Institute operates with electron energy 2.5 GeV and current up to 200 mA. In order to expand spectral range of SR and to increase brightness an installation of 7.5 T 19-pole superconducting wiggler is planned at the end of 2006. Now the wiggler is under fabrication in BINP, Novosibirsk. Such high level of a magnetic field in the wiggler will have a great influence on electron beam parameters of Siberia-2. Changes of these parameters (betatron tunes, horizontal emittance of the electron beam, momentum compaction, energy spread etc.) are discussed in the report. Different methods of compensation (global and local) of betatron functions distortion are presented. Much attention is paid to dynamic aperture calculations using analytical approximation of magnetic field behavior in transverse horizontal direction

Fan beam intensity modulated proton therapy

Science.gov (United States)

Hill, Patrick M.

A fan beam proton therapy is developed which delivers intensity modulated proton therapy using distal edge tracking. The system may be retrofit onto existing proton therapy gantries without alterations to infrastructure in order to improve treatments through intensity modulation. A novel range and intensity modulation system is designed using acrylic leaves that are inserted or retracted from subsections of the fan beam. Leaf thicknesses are chosen in a base-2 system and motivated in a binary manner. Dose spots from individual beam channels range between 1 and 5 cm. Integrated collimators attempting to limit crosstalk among beam channels are investigated, but found to be inferior to uncollimated beam channel modulators. A treatment planning system performing data manipulation in MATLAB and dose calculation in MCNPX is developed. Beamlet dose is calculated on patient CT data and a fan beam source is manually defined to produce accurate results. An energy deposition tally follows the CT grid, allowing straightforward registration of dose and image data. Simulations of beam channels assume that a beam channel either delivers dose to a distal edge spot or is intensity modulated. A final calculation is performed separately to determine the deliverable dose accounting for all sources of scatter. Treatment plans investigate the effects that varying system parameters have on dose distributions. Beam channel apertures may be as large as 20 mm because the sharp distal falloff characteristic of proton dose provides sufficient intensity modulation to meet dose objectives, even in the presence of coarse lateral resolution. Dose conformity suffers only when treatments are delivered from less than 10 angles. Jaw widths of 1--2 cm produce comparable dose distributions, but a jaw width of 4 cm produces unacceptable target coverage when maintaining critical structure avoidance. Treatment time for a prostate delivery is estimated to be on the order of 10 minutes. Neutron production

Purification and treatment of industrial wastewater by electron beam process: it's potential and effectiveness evaluation

International Nuclear Information System (INIS)

Zulkafli Ghazali; Khomsaton Abu Bakar; Ting Teo Ming; Siti Aiasah Hashim; Khairul Zaman Mohd Dahlan

2002-01-01

Demand for water has grown dramatically globally. We have seen how acute is the demand for treated water in Malaysia during dry spell of late. Between 1900 and 1995, water consumption increased by over six times, globally, more than double the rate of population growth. This rapid growth in water demand is due to the increasing reliance on irrigation to achieve food security, the growth of industries, and the increasing use for domestic purposes. Given the seriousness of the situation and future risk of crises, there is an urgent need to develop the water-efficient technologies including economical treatment methods of wastewater and polluted water. Electron beam treatment (E-Beam treatment) is a comparatively new method of wastewater purification. E-beam treatment is also an environment-friendly approach for the cleanup of contaminated groundwater and industrial wastewater. E-beam treatment treats multi-components waste streams and does not require any hazardous chemical additives nor does it create any secondary wastes. It uses fast formation of short-lived reactive particles, which are capable of efficient decomposition of pollutants inside wastewater. This paper highlights the practical treatment of wastewater using E-Beam method that gives essential conveniences and advantages of the followings: - strongest reducing and oxidizing agents; - universality and interchangeability of redox agents; - variety of paths for pollutant conversion; - process controllability; - wide choice of equipment and technological regimes; - compatibility with conventional methods. (Author)

Effect of beam arrangement on oral cavity dose in external beam radiotherapy of nasopharyngeal carcinoma

International Nuclear Information System (INIS)

Wu, Vincent W.C.; Yang Zhining; Zhang Wuzhe; Wu Lili; Lin Zhixiong

2012-01-01

This study compared the oral cavity dose between the routine 7-beam intensity-modulated radiotherapy (IMRT) beam arrangement and 2 other 7-beam IMRT with the conventional radiotherapy beam arrangements in the treatment of nasopharyngeal carcinoma (NPC). Ten NPC patients treated by the 7-beam routine IMRT technique (IMRT-7R) between April 2009 and June 2009 were recruited. Using the same computed tomography data, target information, and dose constraints for all the contoured structures, 2 IMRT plans with alternative beam arrangements (IMRT-7M and IMRT-7P) by avoiding the anterior facial beam and 1 conventional radiotherapy plan (CONRT) were computed using the Pinnacle treatment planning system. Dose-volume histograms were generated for the planning target volumes (PTVs) and oral cavity from which the dose parameters and the conformity index of the PTV were recorded for dosimetric comparisons among the plans with different beam arrangements. The dose distributions to the PTVs were similar among the 3 IMRT beam arrangements, whereas the differences were significant between IMRT-7R and CONRT plans. For the oral cavity dose, the 3 IMRT beam arrangements did not show significant difference. Compared with IMRT-7R, CONRT plan showed a significantly lower mean dose, V30 and V-40, whereas the V-60 was significantly higher. The 2 suggested alternative beam arrangements did not significantly reduce the oral cavity dose. The impact of varying the beam angles in IMRT of NPC did not give noticeable effect on the target and oral cavity. Compared with IMRT, the 2-D conventional radiotherapy irradiated a greater high-dose volume in the oral cavity.

Research and development on municipal Wastewater treatment processes using electron beams

International Nuclear Information System (INIS)

Kashiwaya, Mamoru

1994-01-01

This paper was described concerning the experimental results and their engineering evaluations on electron beam irradiation treatment to effluent and sludge produced in existing municipal wastewater treatment plants implemented by the Japan Atomic Energy Research Institute and the study committee for past five years. Laboratory tests using an electron accelerator were carried out for the purposes of disinfection both to effluent and to dewatered sludge. And composting tests by a pilot-plant were also carried out to find the optimal conditions on design and operation, and initial and operational cost estimations for pelletized sludge with/without the irradiation. It was found that these applications to effluent, sludge and supernatant were quite effective. However, several problems awaiting solution were found from the tests and evaluating works on the matters of marketed electron accelerators. As the results of tests and evaluating works, electron beam irradiation treatment process applied to effluent should be carried out at the municipal wastewater treatment plants. Regenerated granular activated carbon treated by electron beam irradiation may also be applicable to remove hazardous organic substances in effluent. However, long-term tests by pilotplants will be necessary to determine the design criteria, operation and maintenance conditions, and so on. For composting of dewatered sludge produced at municipal wastewater treatment plants, several sizes of smaller electron accelerator are required to be on the market. Especially, medium and small sizes municipalities expect to install composting facilities in the plant. (J.P.N.)

Brain tumors and synchrotron radiation: new methods for mini-beams radiation therapy and treatment follow-up by functional imaging

International Nuclear Information System (INIS)

Deman, P.

2012-01-01

An innovative method of synchrotron radiation therapy, called mini-beams, was proposed by A. Dilmanian et al. in 2006. Mini-beams consists in tumor irradiation with monochromatic sub-millimetric x-ray beams spatially fractionated produced by a synchrotron source. To obtain a homogeneous dose in the target volume, an interleaving is realized using two orthogonal incidences. Adjacent healthy tissue is only partially irradiated by mini-beams, the areas between the beams only receive scattered radiation and therefore the energy deposited is 10 to 15 times lower than on one mini-beam axis, leading to a sparing effect of healthy tissue even when a high dose is deposited in the target volume. The thesis project is the development of this experimental method of monochromatic mini-beams, which involves the control of the irradiation geometry, the control of dosimetry and its modeling by Monte Carlo simulations. To evaluate the method, preclinical experiments on models of brain tumors implanted in rats (F98) are performed. Follow-up by anatomical and functional imaging is carried out to evaluate the effectiveness of the treatment. Functional imaging of cerebral perfusion (volume and cerebral blood flow, mean transit time of heavy elements) appears to be associated in the literature as a relevant method for monitoring prognostic. The key parameters of the cerebral vasculature are mainly studied in magnetic resonance imaging (MRI), because of the harmlessness of this imaging modality. The relation between MRI signal and contrast agent concentration is very complex and no quantitative relationship is well known. Synchrotron Radiation Computed Tomography (SRCT) is an imaging modality with performances to measure absolute contrast agent concentration very close to the theoretical limits and can be used as gold-standard. The used pharmacokinetic models need as input parameters a contrast agent concentration versus time. A comparison of perfusion measurements between MRI and SRCT

The combined effects of e-beam irradiation and microwaves on starch, flour and ingredients

International Nuclear Information System (INIS)

Ferdes, O.S.; Martin, D.; Minea, R.; Tirlea, A.; Badea, M.

1998-01-01

The influences of both microwave field and electron beam irradiation, separately and combined, mainly on physical parameters of corn starch, wheat flour and black pepper were studied. These treatments have been used to achieve the hygienic and microbiological quality requirements of these materials and for their dehydration. The electron-beam irradiation has been carried out by using an ALIN-7 linear accelerator with the following parameters: electron mean energy 6 MeV, mean bean current 10 μA, pulse period 3.5 μs. repetition frequency 100 Hz. For microwave experiments, a special designed microwave applicator consisting of a special cavity, a power controlled generator with a 2.45 GHz standard frequency CW magnetron of 850 W maximum output power was used. The experiments were carried out in 5 variants: microwave treatment solely; electron beam irradiation solely; microwave treatment followed by electron beam irradiation; electron beam irradiation followed by microwave treatment; simultaneous microwave and electron beam treatment. The samples were treated by microwaves at 4 different power values from 250 W to 550 W for 5 different exposure times. The electron beam irradiation took place within the dose range of 1 - 10 kGy, at the same dose rate of approximately 2 kGy/min. The influence of these two physical fields on some common properties (r.h., pH), spectrophotometric (UV-VIS spectra), viscometric (rheograms) and microbiological (CFU/g) properties of the food materials was evaluated. A direct relationship between the variables was observed. The microwave effects are mainly thermal effects, although a non-thermal effect was also observed. The main microbiocidal action is due to the electron beam effect, although the microwave treatment affects sometimes significantly both the microbial population and its sensitivity to irradiation. The combined treatment indicates the presence of a synergistic effect of microwaves and electron-beams, which is of non

Proposed parameters for a circular particle accelerator for proton beam therapy obtained by genetic algorithm

International Nuclear Information System (INIS)

Campos, Gustavo L.; Campos, Tarcísio P.R.

2017-01-01

This paper brings to light optimized proposal for a circular particle accelerator for proton beam therapy purposes (named as ACPT). The methodology applied is based on computational metaheuristics based on genetic algorithms (GA) were used to obtain optimized parameters of the equipment. Some fundamental concepts in the metaheuristics developed in Matlab® software will be presented. Four parameters were considered for the proposed modeling for the equipment, being: potential difference, magnetic field, length and radius of the resonant cavity. As result, this article showed optimized parameters for two ACPT, one of them used for ocular radiation therapy, as well some parameters that will allow teletherapy, called in order ACPT - 65 and ACPT - 250, obtained through metaheuristics based in GA. (author)

Proposed parameters for a circular particle accelerator for proton beam therapy obtained by genetic algorithm

Energy Technology Data Exchange (ETDEWEB)

Campos, Gustavo L.; Campos, Tarcísio P.R., E-mail: gustavo.lobato@ifmg.edu.br, E-mail: tprcampos@pq.cnpq.br, E-mail: gustavo.lobato@ifmg.edu.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

2017-07-01

This paper brings to light optimized proposal for a circular particle accelerator for proton beam therapy purposes (named as ACPT). The methodology applied is based on computational metaheuristics based on genetic algorithms (GA) were used to obtain optimized parameters of the equipment. Some fundamental concepts in the metaheuristics developed in Matlab® software will be presented. Four parameters were considered for the proposed modeling for the equipment, being: potential difference, magnetic field, length and radius of the resonant cavity. As result, this article showed optimized parameters for two ACPT, one of them used for ocular radiation therapy, as well some parameters that will allow teletherapy, called in order ACPT - 65 and ACPT - 250, obtained through metaheuristics based in GA. (author)

Image-guided small animal radiation research platform: calibration of treatment beam alignment

International Nuclear Information System (INIS)

Matinfar, Mohammad; Iordachita, Iulian; Kazanzides, Peter; Ford, Eric; Wong, John

2009-01-01

Small animal research allows detailed study of biological processes, disease progression and response to therapy with the potential to provide a natural bridge to the clinical environment. The small animal radiation research platform (SARRP) is a portable system for precision irradiation with beam sizes down to approximately 0.5 mm and optimally planned radiation with on-board cone-beam CT (CBCT) guidance. This paper focuses on the geometric calibration of the system for high-precision irradiation. A novel technique for the calibration of the treatment beam is presented, which employs an x-ray camera whose precise positioning need not be known. Using the camera system we acquired a digitally reconstructed 3D 'star shot' for gantry calibration and then developed a technique to align each beam to a common isocenter with the robotic animal positioning stages. The calibration incorporates localization by cone-beam CT guidance. Uncorrected offsets of the beams with respect to the calibration origin ranged from 0.4 mm to 5.2 mm. With corrections, these alignment errors can be reduced to the sub-millimeter range. The calibration technique was used to deliver a stereotactic-like arc treatment to a phantom constructed with EBT Gafchromic films. All beams were shown to intersect at a common isocenter with a measured beam (FWHM) of approximately 1.07 mm using the 0.5 mm collimated beam. The desired positioning accuracy of the SARRP is 0.25 mm and the results indicate an accuracy of 0.2 mm. To fully realize the radiation localization capabilities of the SARRP, precise geometric calibration is required, as with any such system. The x-ray camera-based technique presented here provides a straightforward and semi-automatic method for system calibration.

Japan’s experience of flue gas treatment by electron beams

International Nuclear Information System (INIS)

Machi, S.

2011-01-01

The electron beam flue gas treatment technology was invented in Japan in 1970's. The paper presents the outlook of the Japanese activities on the development and present state of EBFGT technology. (author)

Japan’s experience of flue gas treatment by electron beams

Energy Technology Data Exchange (ETDEWEB)

Machi, S.

2011-07-01

The electron beam flue gas treatment technology was invented in Japan in 1970's. The paper presents the outlook of the Japanese activities on the development and present state of EBFGT technology. (author)

Use of an INGRES database to implement the beam parameter management at GANIL

Energy Technology Data Exchange (ETDEWEB)

Gillette, P.; Lecorche, E.; Lermine, P.; Maugeais, C.; Leboucher, Ch.; Moscatello, M.H.; Pain, P.

1995-12-31

Since the beginning of the operation driven by the new Ganil control system in February 1993, the relational database management system (RDBMS) Ingres has been more and more widely used. The most significant application relying on the RDBMS is the new beam parameter management which has been entirely redesigned. It has been operational since the end of the machine shutdown in July this year. After a short recall of the use of Ingres inside the control system, the organization of the parameter management is presented. Then the database implementation is shown, including the way how the physical aspects of the Ganil tuning have been integrated in such an environment. (author). 2 refs.

Use of an INGRES database to implement the beam parameter management at GANIL

Energy Technology Data Exchange (ETDEWEB)

Gillette, P; Lecorche, E; Lermine, P; Maugeais, C; Leboucher, Ch; Moscatello, M H; Pain, P

1996-12-31

Since the beginning of the operation driven by the new Ganil control system in February 1993, the relational database management system (RDBMS) Ingres has been more and more widely used. The most significant application relying on the RDBMS is the new beam parameter management which has been entirely redesigned. It has been operational since the end of the machine shutdown in July this year. After a short recall of the use of Ingres inside the control system, the organization of the parameter management is presented. Then the database implementation is shown, including the way how the physical aspects of the Ganil tuning have been integrated in such an environment. (author). 2 refs.

High-order dynamic modeling and parameter identification of structural discontinuities in Timoshenko beams by using reflection coefficients

Science.gov (United States)

Fan, Qiang; Huang, Zhenyu; Zhang, Bing; Chen, Dayue

2013-02-01

Properties of discontinuities, such as bolt joints and cracks in the waveguide structures, are difficult to evaluate by either analytical or numerical methods due to the complexity and uncertainty of the discontinuities. In this paper, the discontinuity in a Timoshenko beam is modeled with high-order parameters and then these parameters are identified by using reflection coefficients at the discontinuity. The high-order model is composed of several one-order sub-models in series and each sub-model consists of inertia, stiffness and damping components in parallel. The order of the discontinuity model is determined based on the characteristics of the reflection coefficient curve and the accuracy requirement of the dynamic modeling. The model parameters are identified through the least-square fitting iteration method, of which the undetermined model parameters are updated in iteration to fit the dynamic reflection coefficient curve with the wave-based one. By using the spectral super-element method (SSEM), simulation cases, including one-order discontinuities on infinite- and finite-beams and a two-order discontinuity on an infinite beam, were employed to evaluate both the accuracy of the discontinuity model and the effectiveness of the identification method. For practical considerations, effects of measurement noise on the discontinuity parameter identification are investigated by adding different levels of noise to the simulated data. The simulation results were then validated by the corresponding experiments. Both the simulation and experimental results show that (1) the one-order discontinuities can be identified accurately with the maximum errors of 6.8% and 8.7%, respectively; (2) and the high-order discontinuities can be identified with the maximum errors of 15.8% and 16.2%, respectively; and (3) the high-order model can predict the complex discontinuity much more accurately than the one-order discontinuity model.

Measurement of parameters of extracted beams of charged particles at the LVE accelerating complex; Izmerenie parametrov vyvedennykh puchkov zaryazhennykh chastits na uskoritel`nom komplekse LVEh

Energy Technology Data Exchange (ETDEWEB)

Balandikov, A N; Volkov, V I; Gorchenko, V M [and others

1996-12-31

Paper described equipment to measure intensity and space parameters of charged particle beams to be output from the JINR synchrophasotron. Equipment of preliminary recording of signals from multiwire ionization chambers was developed to measure space parameters of beams. 6 refs.; 5 figs.

Signal shape registration in the JINR synchrophasotron slowly extracted beam parameter control system

International Nuclear Information System (INIS)

Volkov, V.I.; Kulikov, I.I.; Romanov, S.V.

1982-01-01

Signal shape registration in the JINR synchrophasotron slowly estracted beam parameter control system on-line with the ES-1010 computer is described. 32 input signals can be connected to the registrator. The maximum measurement rate of signal shape registration is about 38 kHz. The registrator consists of 32-channel analog multiplexer, 10-bit analog-to-digital converter, 1024-word buffer memory and control circuits. For information representation the colour TV monitor is used

Experimental observations and theoretical models for beam-beam phenomena

Energy Technology Data Exchange (ETDEWEB)

Kheifets, S.

1981-03-01

The beam-beam interaction in storage rings exhibits all the characteristics of nonintegrable dynamical systems. Here one finds all kinds of resonances, closed orbits, stable and unstable fixed points, stochastic layers, chaotic behavior, diffusion, etc. The storage ring itself being an expensive device nevertheless while constructed and put into operation presents a good opportunity of experimentally studying the long-time behavior of both conservative (proton machines) and nonconservative (electron machines) dynamical systems - the number of bunch-bunch interactions routinely reaches values of 10/sup 10/-10/sup 11/ and could be increased by decreasing the beam current. At the same time the beam-beam interaction puts practical limits for the yield of the storage ring. This phenomenon not only determines the design value of main storage ring parameters (luminosity, space charge parameters, beam current), but also in fact prevents many of the existing storage rings from achieving design parameters. Hence, the problem has great practical importance along with its enormous theoretical interest. A brief overview of the problem is presented.

Experimental observations and theoretical models for beam-beam phenomena

International Nuclear Information System (INIS)

Kheifets, S.

1981-03-01

The beam-beam interaction in storage rings exhibits all the characteristics of nonintegrable dynamical systems. Here one finds all kinds of resonances, closed orbits, stable and unstable fixed points, stochastic layers, chaotic behavior, diffusion, etc. The storage ring itself being an expensive device nevertheless while constructed and put into operation presents a good opportunity of experimentally studying the long-time behavior of both conservative (proton machines) and nonconservative (electron machines) dynamical systems - the number of bunch-bunch interactions routinely reaches values of 10 10 -10 11 and could be increased by decreasing the beam current. At the same time the beam-beam interaction puts practical limits for the yield of the storage ring. This phenomenon not only determines the design value of main storage ring parameters (luminosity, space charge parameters, beam current), but also in fact prevents many of the existing storage rings from achieving design parameters. Hence, the problem has great practical importance along with its enormous theoretical interest. A brief overview of the problem is presented

Impact of Spot Size and Beam-Shaping Devices on the Treatment Plan Quality for Pencil Beam Scanning Proton Therapy

International Nuclear Information System (INIS)

Moteabbed, Maryam; Yock, Torunn I.; Depauw, Nicolas; Madden, Thomas M.; Kooy, Hanne M.; Paganetti, Harald

2016-01-01

Purpose: This study aimed to assess the clinical impact of spot size and the addition of apertures and range compensators on the treatment quality of pencil beam scanning (PBS) proton therapy and to define when PBS could improve on passive scattering proton therapy (PSPT). Methods and Materials: The patient cohort included 14 pediatric patients treated with PSPT. Six PBS plans were created and optimized for each patient using 3 spot sizes (∼12-, 5.4-, and 2.5-mm median sigma at isocenter for 90- to 230-MeV range) and adding apertures and compensators to plans with the 2 larger spots. Conformity and homogeneity indices, dose-volume histogram parameters, equivalent uniform dose (EUD), normal tissue complication probability (NTCP), and integral dose were quantified and compared with the respective PSPT plans. Results: The results clearly indicated that PBS with the largest spots does not necessarily offer a dosimetric or clinical advantage over PSPT. With comparable target coverage, the mean dose (D_m_e_a_n) to healthy organs was on average 6.3% larger than PSPT when using this spot size. However, adding apertures to plans with large spots improved the treatment quality by decreasing the average D_m_e_a_n and EUD by up to 8.6% and 3.2% of the prescribed dose, respectively. Decreasing the spot size further improved all plans, lowering the average D_m_e_a_n and EUD by up to 11.6% and 10.9% compared with PSPT, respectively, and eliminated the need for beam-shaping devices. The NTCP decreased with spot size and addition of apertures, with maximum reduction of 5.4% relative to PSPT. Conclusions: The added benefit of using PBS strongly depends on the delivery configurations. Facilities limited to large spot sizes (>∼8 mm median sigma at isocenter) are recommended to use apertures to reduce treatment-related toxicities, at least for complex and/or small tumors.

Impact of Spot Size and Beam-Shaping Devices on the Treatment Plan Quality for Pencil Beam Scanning Proton Therapy

Energy Technology Data Exchange (ETDEWEB)

Moteabbed, Maryam, E-mail: mmoteabbed@partners.org; Yock, Torunn I.; Depauw, Nicolas; Madden, Thomas M.; Kooy, Hanne M.; Paganetti, Harald

2016-05-01

Purpose: This study aimed to assess the clinical impact of spot size and the addition of apertures and range compensators on the treatment quality of pencil beam scanning (PBS) proton therapy and to define when PBS could improve on passive scattering proton therapy (PSPT). Methods and Materials: The patient cohort included 14 pediatric patients treated with PSPT. Six PBS plans were created and optimized for each patient using 3 spot sizes (∼12-, 5.4-, and 2.5-mm median sigma at isocenter for 90- to 230-MeV range) and adding apertures and compensators to plans with the 2 larger spots. Conformity and homogeneity indices, dose-volume histogram parameters, equivalent uniform dose (EUD), normal tissue complication probability (NTCP), and integral dose were quantified and compared with the respective PSPT plans. Results: The results clearly indicated that PBS with the largest spots does not necessarily offer a dosimetric or clinical advantage over PSPT. With comparable target coverage, the mean dose (D{sub mean}) to healthy organs was on average 6.3% larger than PSPT when using this spot size. However, adding apertures to plans with large spots improved the treatment quality by decreasing the average D{sub mean} and EUD by up to 8.6% and 3.2% of the prescribed dose, respectively. Decreasing the spot size further improved all plans, lowering the average D{sub mean} and EUD by up to 11.6% and 10.9% compared with PSPT, respectively, and eliminated the need for beam-shaping devices. The NTCP decreased with spot size and addition of apertures, with maximum reduction of 5.4% relative to PSPT. Conclusions: The added benefit of using PBS strongly depends on the delivery configurations. Facilities limited to large spot sizes (>∼8 mm median sigma at isocenter) are recommended to use apertures to reduce treatment-related toxicities, at least for complex and/or small tumors.

Electron beam treatment of wastewater

International Nuclear Information System (INIS)

Arai, H.; Hosono, M.; Shimizu, K.; Sugiyama, M.

1991-01-01

Supernatant comes from dewaterization of sewage sludge, and contains biologically nondegradable organics so that it is hard to be treated by conventional activated sludge. By electron beam (EB) irradiation, any kinds of organics in water can be oxidized to biodegradable organic acids. We studied the treatment of supernatant by application of this effect. The direct irradiation of the original supernatant was found not to be so effective to decrease COD. In order to increase the irradiation effect, supernatant was pretreated biologically to decrease the biodegradable organics in it. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were decreased from 800 and 910 mg/L to 78 and 5 mg/L by this pretreatment, respectively. This pretreated supernatant was irradiated by EB of 2 MeV using a batch type reactor. The COD was gradually decreased with dose. In contrast, BOD was increased markedly, indicating increase in biodegradability. The irradiated sample water was treated biologically again. After the final biological treatment, COD was decreased below 30 mg/L in the case of 10 - 12 kGy irradiation. Finally, the initial COD of 800 mg/L was decreased below 30 mg/L by the combination of EB irradiation and biological treatment. The cost of irradiation for this process was evaluated preliminarily. (author)

Laser ablation: Laser parameters: Frequency, pulse length, power, and beam charter play significant roles with regard to sampling complex samples for ICP/MS analysis

International Nuclear Information System (INIS)

Smith, M.R.; Alexander, M.L.; Hartman, J.S.; Koppenaal, D.W.

1996-01-01

Inductively coupled plasma mass spectrometry is used to investigate the influence of laser parameters with regard to sampling complex matrices ranging from relatively homogenous glasses to multi-phase sludge/slurry materials including radioactive Hanford tank waste. The resulting plume composition caused by the pulsed laser is evaluated as a function of wavelength, pulse energy, pulse length, focus, and beam power profiles. The author's studies indicate that these parameters play varying and often synergistic roles regarding quantitative results. (In a companion paper, particle transport and size distribution studies are presented.) The work described here will illustrate other laser parameters such as focusing and consequently power density and beam power profiles which are shown to influence precision and accuracy. Representative sampling by the LA approach is largely dependent on the sample's optical properties as well as laser parameters. Experimental results indicate that optimal laser parameters; short wavelength (UV), relatively low power (300 mJ), low-to-sub ns pulse lengths, and laser beams with reasonable power distributions (i.e., Gaussian or top-hat beam profiles) provide superior precision and accuracy. Remote LA-ICP/MS analyses of radioactive sludges are used to illustrate these optimal conditions laser ablation sampling

Relativistic treatment of Raman free-electro laser in beam frame

International Nuclear Information System (INIS)

Korbacheh, A.; Maraghechi, B.; Aghahosseni, H.

2004-01-01

A relativistic theory for Raman backscattering in the beam frame of electrons is used to find the growth rate of free- electron laser in Raman regime. The electromagnetic effects of the space-charge wave are taken into account by using the electrostatic approximation in the beam frame. The wiggler effects on the linear dispersion relations of the space- charge wave and radiation are included in the analysis. A numerical computation is conducted to compare the growth rate of the excited waves with nonrelativistic treatment

Energy transparency and symmetries in the beam-beam interaction

CERN Document Server

Krishnagopal, S

2000-01-01

We have modified the beam-beam simulation code CBI to handle asymmetric beams and used it to look at energy transparency and symmetries in the beam-beam interaction. We find that even a small violation of energy transparency, or of the symmetry between the two beams, changes the character of the collective (coherent) motion; in particular, period-n oscillations are no longer seen. We speculate that the one-time observation of these oscillations at LEP, and the more ubiquitous observation of the flip-flop instability in colliders around the world, may be a consequence of breaking the symmetry between the electron and positron beams. We also apply this code to the asymmetric collider PEP-II, and find that for the nominal parameters of PEP-II, in particular, the nominal tune-shift parameter of xi /sub 0/=0.03, there are no collective beam-beam issues. Collective quadrupole motion sets in only at xi /sub 0/=0.06 and above, consistent with earlier observations for symmetric beams. (6 refs).

Lie Algebraic Treatment of Linear and Nonlinear Beam Dynamics

Energy Technology Data Exchange (ETDEWEB)

Alex J. Dragt; Filippo Neri; Govindan Rangarajan; David Douglas; Liam M. Healy; Robert D. Ryne

1988-12-01

The purpose of this paper is to present a summary of new methods, employing Lie algebraic tools, for characterizing beam dynamics in charged-particle optical systems. These methods are applicable to accelerator design, charged-particle beam transport, electron microscopes, and also light optics. The new methods represent the action of each separate element of a compound optical system, including all departures from paraxial optics, by a certain operator. The operators for the various elements can then be concatenated, following well-defined rules, to obtain a resultant operator that characterizes the entire system. This paper deals mostly with accelerator design and charged-particle beam transport. The application of Lie algebraic methods to light optics and electron microscopes is described elsewhere (1, see also 44). To keep its scope within reasonable bounds, they restrict their treatment of accelerator design and charged-particle beam transport primarily to the use of Lie algebraic methods for the description of particle orbits in terms of transfer maps. There are other Lie algebraic or related approaches to accelerator problems that the reader may find of interest (2). For a general discussion of linear and nonlinear problems in accelerator physics see (3).

Parameters of medical proton beam of JINR and study on its medical use

International Nuclear Information System (INIS)

Dzhelepov, V.P.; Abazov, V.M.; Komarov, V.I.; Kuz'min, E.S.; Reshetnikov, G.P.; Savchenko, O.V.; Cherevatenko, E.P.; Ruderman, A.I.; Astrakhan, B.V.; Vajnberg, M.Sh.

1975-01-01

Experiments are described on irradiation of deep-lying tumours in man with a proton beam on the Dubna synchrocyclotron. A proton beam with an energy of 680 MeV is focused on a braking filter of liquid paraffin or water, 1.5 m thick. The slowed-down protons are cleared of impurity particles by the magnetic field and are transported for about 30 m to clinical premises located behind a 2 m concrete shield. The total intensity and maximum density of the proton flux with an energy of 185 MeV are about 10 9 s -1 and 5x10 7 cm -2 s -1 , respectively. The results of dose measurements showed that the maximum dose rate is about 300 rad/min at a proton energy of 185 MeV, and about 120 rad/min at 90 MeV. The contribution of the secondary particles to the dose distribution is about 10%. Patients can be irradiated either in the static regime, or in the rotation regime, when the patient rotates about a vertical axis passing through the tumour centre. While the patient is rotating, all the changes in the thickness of the tissues through which the beam passes before it reaches the tumour, are automatically compensated by a change in the thickness of the water absorber installed in front of the patient. Irradiations of patients with surface tumours showed that the proton beam parameters and the technical equipment of the systems meet the medical requirements

Electron-beam flue gas treatment

International Nuclear Information System (INIS)

Aoki, Shinji

1990-01-01

A new flue gas treatment process (EBA process) using an electron beam will be discussed. This EBA process is attracting worldwide attention as a new effective measure for solving acid rain problems and jointly developed by Ebara Corporation and the Japan Atomic Energy Research Institute. This process has many advantages: a) a dry process capable of removing high level SO x and NO x simultaneously, b) a process simple and easy to operate, c) production of agricultural fertilizers as salable by-products, and d) minimal installation space. Test results from the demonstration plant (max. gas flow rate of 24,000 m 3 N/h) which was erected in a coal-fired power station in Indianapolis, Indiana, U.S.A. will be presented. (author)

Beam interlock system and safe machine parameters system 2010 and beyond

CERN Document Server

Todd, B

2010-01-01

The Beam Interlock System (BIS) and Safe Machine Parameters (SMP) system are central to the protection of the Large Hadron Collider (LHC) machine. The BIS has been critical for the safe operation of LHC from the first day of operation. It has been installed and commissioned, only minor enhancements are required in order to accommodate all future LHC machine protection requirements. At reduced intensity, the SMP system is less critical for LHC operation. As such, the current system satisfies the 2010 operational requirements. Further developments are required, both at the SMP Controller level, and at the system level, in order to accommodate the requirements of the LHC beyond 2010.

Overview of the Beam diagnostics in the Medaustron Accelerator:Design choices and test Beam commissioning

CERN Document Server

Osmic, F; Gyorgy, A; Kerschbaum, A; Repovz, M; Schwarz, S; Neustadt, W; Burtin, G

2012-01-01

The MedAustron centre is a synchrotron based accelerator complex for cancer treatment and clinical and non-clinical research with protons and light ions, currently under construction in Wiener Neustadt, Austria. The accelerator complex is based on the CERN-PIMMS study [1] and its technical implementation by the Italian CNAO foundation in Pavia [2]. The MedAustron beam diagnostics system is based on sixteen different monitor types (153 devices in total) and will allow measuring all relevant beam parameters from the source to the irradiation rooms. The monitors will have to cope with large intensities and energy ranges. Currently, one ion source, the low energy beam transfer line and the RFQ are being commissioned in the Injector Test Stand (ITS) at CERN. This paper gives an overview of all beam monitors foreseen for the MedAustron accelerator, elaborates some of the design choices and reports the first beam commissioning results from the ITS.

Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners

Directory of Open Access Journals (Sweden)

Taiki Magome

2013-01-01

Full Text Available Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT to assist treatment planners. Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP. Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences (P<0.05 in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung. Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT.

Beam-beam effect and luminosity in SPEAR

International Nuclear Information System (INIS)

Wiedemann, H.

1980-01-01

Many measurements on the beam-beam limit in SPEAR have been performed over the past years. The goal for these measurements was to find the proper parameterization of the beam-beam effect. All measurements presented were done with both beams equally blown up by control of the flip-flop phenomenon. Colliding beam measurements were made at energies as low as 600 MeV and together with earlier measurements the author presents the scaling of some relevant storage ring parameters from 600 MeV up to almost 4 GeV. (Auth.)

Determination of Penetration Depth of 800 keV Electron Beam into Coal Fired Power Plant Flue Gas at in a Electron Beam Machine Flue Gas Treatment System

International Nuclear Information System (INIS)

Rany Saptaaji

2008-01-01

Penetration depth calculation of 800 keV electron beam into flue gas from coal fired power plan is presented in this paper. Electron Beam for Flue Gas Treatment (EB-FGT) is a dry treatment process using electron beam to simultaneously reduce SO 2 and NO x . Flue gas irradiation produces active radicals and then reaction with SO 2 and NO x produces nitrate acid and sulphate acid. Process vessel is needed in this process as reaction container of flue gas with electron beam. The calculation of electron beam penetration depth into flue gas is used to determine the process vessel dimension. The result of calculation of optimum penetration depth of 800 keV electron beam into flue gas is 188.67 cm. (author)

The study of PDMS surface treatment and it's applications by using proton beam

Energy Technology Data Exchange (ETDEWEB)

Baek, J. Y.; Kim, J. Y.; Kwon, K. H.; Park, J. Y. [Korea Univ., Seoul (Korea, Republic of)

2007-04-15

PDMS(Polydimethylsiloxane) is mainly used as a material to do lab on a chip for biochemical analysis. PDMS has many applicability at the Bio-Technology(BT) field, because it is flexible, biocompatible and has good oxygen permeability. In this study, we have investigated to physical and chemical changes of PDMS surface by proton beam radiation conditions. The used kind of ion were Ar and N, beam energy was 30keV, 60keV, 80keV, total fluence was 1E10 to 1E16 [ions/cm{sup 2}]. PDMS membrane was produced as 150 {mu}m thick on the 3' silicon wafer. We inquired into physical and chemical changes up to beam radiation conditions through the investigate the change of surface roughness by AFM(Atomic Force Microscope), the change of surface morphology by SEM(Scanning Electron Microscope) and the change of chemical composition by FT-IR(Fourier Transform Infrared Raman spectroscopy) and XPS(X-ray Photoelectron Spectroscopy). From these basic data to we set up the proton beam radiation conditions to secure metal layer and PDMS adhesion. This enables to produce the electrode at the PDMS material lab on a chip. From now on, we'll investigate the cell patterning possibility after carry out of cell culture with mouse fibroblast at PDMS surface what is surface modification by using of proton beam radiation and apply this to produce lab on a chip. Physical property: Surface roughness of PDMS membrane was observed using AFM, after exposure of proton beam on it. The roughness increased as the power level of proton beam increase. This phenomena was caused by the kinetic energy of particle. Chemical property: Long term observation was conducted on the contact angles of the samples made by the proton beam exposure or oxygen plasma treatment; the hydrophilicity was found to be stronger in the samples made by the proton beam exposure. We found the reason of this was the destruction of polymer chains by proton beam. Feasibility of Through-hole: Considering that comparatively high

SU-E-T-353: Decoding the Beam Complexity in Intensity-Modulated Radiation Therapy Plans

International Nuclear Information System (INIS)

Du, W; Cho, S; Zhang, X; Hoffman, K; Kudchadker, R

2014-01-01

Purpose: Modern IMRT relies on computers to generate treatment plans of varied complexity. A highly complex treatment plan may use a large number of small and irregular beam apertures in order to achieve high dose conformity. However, excessive beam complexity can increase dosimetric uncertainty, prolong treatment time, and increase susceptibility to target or organ motion. In this study we sought to develop metrics to assess the complexity of IMRT beams and plans. Methods: Based the information of leaf positions and MU for each beam segment, we calculated the following beam complexity metrics: aperture area, shape irregularity, and beam modulation. Then these beam complexity metrics were averaged to obtain the corresponding plan complexity metrics, using the beam MUs as weighting factors. We evaluated and compared the beam and plan complexity scores for 65 IMRT plans from 3 sites (prostate, head and neck, and spine). We also studied how the plan complexity scores were affected by adjusting inverse planning parameters. Results: For prostate IMRT, the lateral beams had large MUs and smaller shape irregularity, while the anterior or posterior beams had larger modulation values. On average, the prostate IMRT plans had the smallest shape irregularity and beam modulation; the HN IMRT plans had the largest aperture area, shape irregularity, and beam modulation; and the spine stereotactic IMRT plans often had small aperture area, which may be associated with relatively large discrepancies between calculated and measures doses. The plan complexity increased as the number of optimization iterations and the number of beam segments increased and as the minimum segment area decreased. Conclusion: Complexity of IMRT beams and plans were quantified in terms of aperture area, shape irregularity and beam modulation. The complexity metrics varied among IMRT plans for different disease sites and were affected when the planning parameters were adjusted

Electron beam treatment planning: A review of dose computation methods

International Nuclear Information System (INIS)

Mohan, R.; Riley, R.; Laughlin, J.S.

1983-01-01

Various methods of dose computations are reviewed. The equivalent path length methods used to account for body curvature and internal structure are not adequate because they ignore the lateral diffusion of electrons. The Monte Carlo method for the broad field three-dimensional situation in treatment planning is impractical because of the enormous computer time required. The pencil beam technique may represent a suitable compromise. The behavior of a pencil beam may be described by the multiple scattering theory or, alternatively, generated using the Monte Carlo method. Although nearly two orders of magnitude slower than the equivalent path length technique, the pencil beam method improves accuracy sufficiently to justify its use. It applies very well when accounting for the effect of surface irregularities; the formulation for handling inhomogeneous internal structure is yet to be developed

Studies of the beam-beam interaction for the LHC

International Nuclear Information System (INIS)

Krishnagopal, S.; Furman, M.A.; Turner, W.C.

1999-01-01

The authors have used the beam-beam simulation code CBI to study the beam-beam interaction for the LHC. We find that for nominal LHC parameters, and assuming only one bunch per beam, there are no collective (coherent) beam-beam instabilities. We have investigated the effect of sweeping one of the beams around the other (a procedure that could be used as a diagnostic for head-on beam-beam collisions). We find that this does not cause any problems at the nominal current, though at higher currents there can be beam blow-up and collective beam motion. consequence of quadrupole collective effects

Implementation of pencil kernel and depth penetration algorithms for treatment planning of proton beams

International Nuclear Information System (INIS)

Russell, K.R.; Saxner, M.; Ahnesjoe, A.; Montelius, A.; Grusell, E.; Dahlgren, C.V.

2000-01-01

The implementation of two algorithms for calculating dose distributions for radiation therapy treatment planning of intermediate energy proton beams is described. A pencil kernel algorithm and a depth penetration algorithm have been incorporated into a commercial three-dimensional treatment planning system (Helax-TMS, Helax AB, Sweden) to allow conformal planning techniques using irregularly shaped fields, proton range modulation, range modification and dose calculation for non-coplanar beams. The pencil kernel algorithm is developed from the Fermi-Eyges formalism and Moliere multiple-scattering theory with range straggling corrections applied. The depth penetration algorithm is based on the energy loss in the continuous slowing down approximation with simple correction factors applied to the beam penumbra region and has been implemented for fast, interactive treatment planning. Modelling of the effects of air gaps and range modifying device thickness and position are implicit to both algorithms. Measured and calculated dose values are compared for a therapeutic proton beam in both homogeneous and heterogeneous phantoms of varying complexity. Both algorithms model the beam penumbra as a function of depth in a homogeneous phantom with acceptable accuracy. Results show that the pencil kernel algorithm is required for modelling the dose perturbation effects from scattering in heterogeneous media. (author)

Treatment of the uterus cervix cancer with the JINR phasotron proton beam

International Nuclear Information System (INIS)

Astrakhan, B.V.; Kiseleva, V.N.; Pojdenko, V.K.; Klochkov, I.I.; Molokanov, A.G.; Mitsin, G.V.; Savchenko, O.V.; Zorin, V.P.

1995-01-01

The methods of the uterus cervix cancer proton-and-gamma treatment for the first time were elaborated in the CRC RAMS and ITEP in Moscow and then developed for the JINR proton beam in Dubna. The results of the clinical probation of the methods for the uterus cervix cancer treatment have confirmed the advantage of the proton irradiation. The most important advantage of the proton beam treatment is absence of postradiation reactions and complications in the critical organs (bladder and rectum). Up to now 31 patients with the uterus cervix cancer have been treated at the JINR phasotron. 6 of them had proton-and-gamma treatment combined with surgical operation and 22 patients received a radical proton-and-gamma treatment (without surgery). The clinical results are in good agreement with the preceding results of the ITEP group. After receiving proton-and-gamma radiotherapy of the uterus cervix, 83% of the patients are alive without recurrences, metastases and complications. 10 refs., 4 figs., 2 tabs

Feature of flue gas treatment by electron-beam irradiation and details of its development

International Nuclear Information System (INIS)

Tokunaga, Okihiro; Suzuki, Nobutake.

1986-01-01

The method of flue gas treatment with an electron beam, developed jointly by Japan Atomic Energy Research Institute and Ebara Corporation, is promising as a simple, dry process, not using a catalyst, of the desulfurization and denitration. In the procedure, flue gas is irradiated with an electron beam in the presence of ammonia, so that sulfurous acid gas and nitrogen oxide are converted to ammonium sulfate and ammonium nitrate particles, which are then removed. The method is already demonstrated in the flue gas treatment of an iron ore sintering furnace as pilot test. And further, the pilot tests in coal combustion flue gas treatment are proceeding in the United States and West Germany. For the flue gas treatment method using an electron beam, the mechanisms of desulfurization and denitration, the course taken in its development and the present state of development are described, and also the future outlook and problems. (Mori, K.)

Investigating multi-objective fluence and beam orientation IMRT optimization

Science.gov (United States)

Potrebko, Peter S.; Fiege, Jason; Biagioli, Matthew; Poleszczuk, Jan

2017-07-01

Radiation Oncology treatment planning requires compromises to be made between clinical objectives that are invariably in conflict. It would be beneficial to have a ‘bird’s-eye-view’ perspective of the full spectrum of treatment plans that represent the possible trade-offs between delivering the intended dose to the planning target volume (PTV) while optimally sparing the organs-at-risk (OARs). In this work, the authors demonstrate Pareto-aware radiotherapy evolutionary treatment optimization (PARETO), a multi-objective tool featuring such bird’s-eye-view functionality, which optimizes fluence patterns and beam angles for intensity-modulated radiation therapy (IMRT) treatment planning. The problem of IMRT treatment plan optimization is managed as a combined monolithic problem, where all beam fluence and angle parameters are treated equally during the optimization. To achieve this, PARETO is built around a powerful multi-objective evolutionary algorithm, called Ferret, which simultaneously optimizes multiple fitness functions that encode the attributes of the desired dose distribution for the PTV and OARs. The graphical interfaces within PARETO provide useful information such as: the convergence behavior during optimization, trade-off plots between the competing objectives, and a graphical representation of the optimal solution database allowing for the rapid exploration of treatment plan quality through the evaluation of dose-volume histograms and isodose distributions. PARETO was evaluated for two relatively complex clinical cases, a paranasal sinus and a pancreas case. The end result of each PARETO run was a database of optimal (non-dominated) treatment plans that demonstrated trade-offs between the OAR and PTV fitness functions, which were all equally good in the Pareto-optimal sense (where no one objective can be improved without worsening at least one other). Ferret was able to produce high quality solutions even though a large number of parameters

Effect of photon-beam energy on VMAT and IMRT treatment plan quality and dosimetric accuracy for advanced prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Pasler, Marlies; Wirtz, Holger; Lutterbach, Johannes [Lake Constance Radiation Oncology Center Singen-Friedrichshafen, Singen (Germany); Georg, Dietmar [Medical Univ. Vienna (Austria). Dept. of Radiotherapy

2011-12-15

The goal of the research was to evaluate treatment plan quality and dosimetric accuracy of volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) plans using 6, 10, and 15 MV photon beams for prostate cancer including lymph nodes. In this retrospective study, VMAT and IMRT plans were generated with the Pinnacle {sup copyright} treatment planning system (TPS) (V9.0) for 10 prostate cancer cases. Each plan consisted of two target volumes: PTV{sub B} included the prostate bed, PTV{sub PC+LN} contained PTV{sub B} and lymph nodes. For plan evaluation statistics, the homogeneity index, conformity index, mean doses, and near-max doses to organs at risk (OAR) were analyzed. Treatment time and number of monitor units were assessed to compare delivery efficiency. Dosimetric plan verification was performed with a 2D ionization chamber array placed in a full scatter phantom. Results: No differences were found for target and OAR parameters in low and high energy photon beam plans for both VMAT and IMRT. A slightly higher low dose volume was detected for 6 MV VMAT plans (normal tissue: D{sub mean} = 16.47 Gy) compared to 10 and 15 MV VMAT plans (D{sub mean} = 15.90 Gy and 15.74 Gy, respectively), similar to the findings in IMRT. In VMAT, > 96% of detector points passed the 3%/ 3 mm {gamma} criterion; marginally better accuracy was found in IMRT (> 97%). Conclusion: For static and rotational IMRT, 15 MV photons did not show advantages over 6 and 10 MV high energy photon beams in large volume pelvic plans. For the investigated TPS and linac combination, 10 MV photon beams can be used as the general purpose energy for intensity modulation.

External beam radiation for retinoblastoma: Results, patterns of failure, and a proposal for treatment guidelines

International Nuclear Information System (INIS)

Hernandez, J. Carlos; Brady, Luther W.; Shields, Jerry A.; Shields, Carol L.; Potter, Patrick de; Karlsson, Ulf L.; Markoe, Arnold M.; Amendola, Beatriz E.; Singh, Arun

1996-01-01

Purpose: To analyze treatment results and patterns of failure following external beam radiation for retinoblastoma and propose treatment guidelines according to specific clinical variables. Methods and Materials: We analyzed 27 patients (34 eyes) with retinoblastoma who received external beam radiation as initial treatment at Hahnemann University Hospital from October 1980 to December 1991 and have been followed for at least 1 year. Of the 34 eyes, 14 were Groups I-II (Reese-Ellsworth classification), 7 were Group III, and 13 were Groups IV-V. Doses ranged from 34.5-49.5 Gy (mean 44.3 Gy, median 45 Gy) in 1.5-2.0 Gy fractions generally delivered through anterior and lateral wedged pair fields. Results: At a mean follow up of 35.2 months (range 12-93 months), local tumor control was obtained in 44% (15 out of 34) of eyes with external beam radiation alone. Salvage therapy (plaque brachytherapy, cryotherapy, and/or photocoagulation) controlled an additional 10 eyes (29.5%), so that overall ocular survival has been 73.5%. Local tumor control with external beam radiotherapy alone was obtained in 78.5% (11 out of 14) of eyes in Groups I-II, but in only 20% (4 out of 20) of eyes in Groups III-V. A total of 67 existing tumors were identified prior to treatment in the 34 treated eyes and local control with external beam radiation alone was obtained in 87% (46 out of 53) of tumors measuring 15 mm or less and in 50% (7 out of 14) of tumors measuring more than 15 mm. When analyzing patterns of failure in the 19 eyes that relapsed, a total of 28 failure sites were identified and consisted of progression of vitreous seeds in seven instances (25% of failure sites) recurrences from previously existing tumors in 10 instances (36% of failure sites) and development of new tumors in previously uninvolved retina in 11 instances (39% of failure sites). Conclusions: 1) We find that external beam radiation to a dose of 45 Gy in fractions of 1.5 to 2.0 Gy provides adequate tumor control

Use of linear programming to obtain an optimum, multi-beam treatment plan in BNCT

International Nuclear Information System (INIS)

Nievaart, Sander; Moss, Ray; Sauerwein, Wolfgang; Wittig, Andrea

2006-01-01

For BNCT of melanoma metastases in the brain, it has been necessary to calculate the dose distributions in the patient for dozens of possible neutron beams and then to combine manually the different beams by individually weighting and adding them. This time consuming approach eventually gave the required treatment plan, which satisfied the prescription dose. However, by linear optimisation with the Simplex method, the optimum weights for a set of beams can be determined mathematically. The objective function to maximise is the minimum averaged physical boron dose in one certain lesion for every set of beams. The maximisation of this objective function is performed under the constraints of certain maximum and minimum dose limits in the organs at risk and lesions respectively and restricting the set of weighted beams to deliver an average total weighted dose of 7 Gy in the brain. After iteration, by using the constraint set for the minimum dose in the lesions as a variable and performed for all combinations of the neutron beams, the optimum beams and weights are found for each treatment. As a preliminary result, the total irradiation time decreased by more than 30%, which is advantageous regarding both the pharmacokinetics of the boron in the patient and patient comfort. (author)

Feasibility of proton pencil beam scanning treatment of free-breathing lung cancer patients

NARCIS (Netherlands)

Jakobi, Annika; Perrin, Rosalind; Knopf, Antje; Richter, Christian

BACKGROUND: The interplay effect might degrade the dose of pencil beam scanning proton therapy to a degree that free-breathing treatment might be impossible without further motion mitigation techniques, which complicate and prolong the treatment. We assessed whether treatment of free-breathing

Computer-aided beam arrangement based on similar cases in radiation treatment-planning databases for stereotactic lung radiation therapy

International Nuclear Information System (INIS)

Magome, Taiki; Shioyama, Yoshiyuki; Arimura, Hidetaka

2013-01-01

The purpose of this study was to develop a computer-aided method for determination of beam arrangements based on similar cases in a radiotherapy treatment-planning database for stereotactic lung radiation therapy. Similar-case-based beam arrangements were automatically determined based on the following two steps. First, the five most similar cases were searched, based on geometrical features related to the location, size and shape of the planning target volume, lung and spinal cord. Second, five beam arrangements of an objective case were automatically determined by registering five similar cases with the objective case, with respect to lung regions, by means of a linear registration technique. For evaluation of the beam arrangements five treatment plans were manually created by applying the beam arrangements determined in the second step to the objective case. The most usable beam arrangement was selected by sorting the five treatment plans based on eight plan evaluation indices, including the D95, mean lung dose and spinal cord maximum dose. We applied the proposed method to 10 test cases, by using an RTP database of 81 cases with lung cancer, and compared the eight plan evaluation indices between the original treatment plan and the corresponding most usable similar-case-based treatment plan. As a result, the proposed method may provide usable beam arrangements, which have no statistically significant differences from the original beam arrangements (P>0.05) in terms of the eight plan evaluation indices. Therefore, the proposed method could be employed as an educational tool for less experienced treatment planners. (author)

Electron beam treatment with radical scavengers/enhancers

International Nuclear Information System (INIS)

Gehringer, P.

1994-08-01

E-beam treatment of low level contaminated groundwater is best apt to demonstrate the role of scavengers and enhancers, respectively because groundwater already contains some scavengers as natural solutes. The action of ionizing radiation to water is known to result in the formation of ions, molecular and free radical species. For low level contaminations of groundwater (pollutant concentration aqu - and H are of interest for pollutant decomposition. The pollutants have to compete for the free radical species with the natural solutes. 10 figures are discussed. (author)

Proton Beam Therapy for Hepatocellular Carcinoma: A Comparison of Three Treatment Protocols

Energy Technology Data Exchange (ETDEWEB)

Mizumoto, Masashi; Okumura, Toshiyuki; Hashimoto, Takayuki [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Fukuda, Kuniaki [Department of Gastroenterology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Oshiro, Yoshiko; Fukumitsu, Nobuyoshi [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Abei, Masato [Department of Gastroenterology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Kawaguchi, Atsushi [Biostatistics Center, Kurume University, Fukuoka (Japan); Hayashi, Yasutaka; Ookawa, Ayako; Hashii, Haruko; Kanemoto, Ayae [Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Moritake, Takashi [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Tohno, Eriko [Department of Diagnostic Radiology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Tsuboi, Koji [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan); Sakae, Takeji [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Sakurai, Hideyuki, E-mail: hsakurai@pmrc.tsukuba.ac.jp [Proton Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, University of Tsukuba, Tsukuba, Ibaraki (Japan)

2011-11-15

Background: Our previous results for treatment of hepatocellular carcinoma (HCC) with proton beam therapy revealed excellent local control with low toxicity. Three protocols were used to avoid late complications such as gastrointestinal ulceration and bile duct stenosis. In this study, we examined the efficacy of these protocols. Methods and Materials: The subjects were 266 patients (273 HCCs) treated by proton beam therapy at University of Tsukuba between January 2001 and December 2007. Three treatment protocols (A, 66 GyE in 10 fractions; B, 72.6 GyE in 22 fractions; and C, 77 GyE in 35 fractions) were used, depending on the tumor location. Results: Of the 266 patients, 104, 95, and 60 patients were treated with protocols A, B, and C, respectively. Seven patients with double lesions underwent two different protocols. The overall survival rates after 1, 3 and 5 years were 87%, 61%, and 48%, respectively (median survival, 4.2 years). Multivariate analysis showed that better liver function, small clinical target volume, and no prior treatment (outside the irradiated field) were associated with good survival. The local control rates after 1, 3, and 5 years were 98%, 87%, and 81%, respectively. Multivariate analysis did not identify any factors associated with good local control. Conclusions: This study showed that proton beam therapy achieved good local control for HCC using each of three treatment protocols. This suggests that selection of treatment schedules based on tumor location may be used to reduce the risk of late toxicity and maintain good treatment efficacy.

Optimized lens-sparing treatment of retinoblastoma with electron beams

International Nuclear Information System (INIS)

Steenbakkers, Roel J.H.M.; Altschuler, Martin D.; D'Angio, Giulio J.; Goldwein, Joel W.; Kassaee, Alireza

1997-01-01

Purpose: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens. Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that approaches this ideal configuration using electron beam therapy. Methods and Materials: Dose-modeling calculations were made using a computer program built around a proprietary algorithm. This program calculates 3D dose distribution for electrons and photons and uses the Cimmino feasibility method for the inverse problem of beam weighting to achieve the prescribed dose. The algorithm has been verified in the ocular region by measurements in a RANDO phantom. To search for an ideal lens-sparing beam setup, a stylized phantom of an 8-month-old infant was generated with built-in inhomogeneities, and a phantom of a 5-year-old child was generated from a patient CT series. Results: Of more than 100 different beam setups tested, two 9 MeV electron beams at gantry angles plus and minus 26 degrees from the optic nerve axis achieved the best distribution. Both fields have a lens block and an isocenter between the globe and origin of the optic nerve. When equal doses are given to both fields, the entire extent of the retina (including ora serrata) received 100%, while the lens received 10% or less. Conclusion: The two-oblique-electron-beam technique here described appears to meet most of the stringent dosimetry needed to treat retinoblastoma. It is suitable for a range of ages, from infancy to early childhood years

A Beam Quality Monitor for LHC Beams in the SPS

CERN Document Server

Papotti, G

2008-01-01

The SPS Beam Quality Monitor (BQM) system monitors the longitudinal parameters of the beam before extraction to the LHC to prevent losses and degradation of the LHC luminosity by the injection of low quality beams. It is implemented in two priority levels. At the highest level the SPS-LHC synchronization and global beam structure are verified. If the specifications are not met, the beam should be dumped in the SPS before extraction. On the second level, individual bunch position, length and stability are checked for beam quality assessment. Tolerances are adapted to the mode of operation and extraction to the LHC can also be inhibited. Beam parameters are accessed by acquiring bunch profiles with a longitudinal pick up and fast digital oscilloscope. The beam is monitored for instabilities during the acceleration cycle and thoroughly checked a few ms before extraction for a final decision on extraction interlock. Dedicated hardware and software components implementing fast algorithms are required. In this pape...

Effects of Processing Parameters on Surface Roughness of Additive Manufactured Ti-6Al-4V via Electron Beam Melting

Science.gov (United States)

Sin, Wai Jack; Nai, Mui Ling Sharon; Wei, Jun

2017-01-01

As one of the powder bed fusion additive manufacturing technologies, electron beam melting (EBM) is gaining more and more attention due to its near-net-shape production capacity with low residual stress and good mechanical properties. These characteristics also allow EBM built parts to be used as produced without post-processing. However, the as-built rough surface introduces a detrimental influence on the mechanical properties of metallic alloys. Thereafter, understanding the effects of processing parameters on the part’s surface roughness, in turn, becomes critical. This paper has focused on varying the processing parameters of two types of contouring scanning strategies namely, multispot and non-multispot, in EBM. The results suggest that the beam current and speed function are the most significant processing parameters for non-multispot contouring scanning strategy. While for multispot contouring scanning strategy, the number of spots, spot time, and spot overlap have greater effects than focus offset and beam current. The improved surface roughness has been obtained in both contouring scanning strategies. Furthermore, non-multispot contouring scanning strategy gives a lower surface roughness value and poorer geometrical accuracy than the multispot counterpart under the optimized conditions. These findings could be used as a guideline for selecting the contouring type used for specific industrial parts that are built using EBM. PMID:28937638

Numerical simulation of electron beam welding with beam oscillations

Science.gov (United States)

Trushnikov, D. N.; Permyakov, G. L.

2017-02-01

This research examines the process of electron-beam welding in a keyhole mode with the use of beam oscillations. We study the impact of various beam oscillations and their parameters on the shape of the keyhole, the flow of heat and mass transfer processes and weld parameters to develop methodological recommendations. A numerical three-dimensional mathematical model of electron beam welding is presented. The model was developed on the basis of a heat conduction equation and a Navier-Stokes equation taking into account phase transitions at the interface of a solid and liquid phase and thermocapillary convection (Marangoni effect). The shape of the keyhole is determined based on experimental data on the parameters of the secondary signal by using the method of a synchronous accumulation. Calculations of thermal and hydrodynamic processes were carried out based on a computer cluster, using a simulation package COMSOL Multiphysics.

Plasma-parameter measurements using neutral-particle-beam attenuation

International Nuclear Information System (INIS)

Foote, J.H.; Molvik, A.W.; Turner, W.C.

1982-01-01

Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure neutral-beam attenuation along chords through the plasma volume at different radial and axial positions. The radial array is used to infer the radial plasma-density profile; the axial array, to infer the axial plasma-density profile and the ion angular distribution at the plasma midplane

Waste treatment by microwave and electron beam irradiation

International Nuclear Information System (INIS)

Martin, D.; Craciun, G.; Manaila, E.; Ighigeanu, D; Oproiu, C.; Iacob, N.; Togoe, I.; Margaritescu, I.

2007-01-01

Comparative results obtained by applying separate and combined (successive and simultaneous) electron beam (EB) and microwave (MW) irradiation to waste treatment, such as food residuals (minced beef, wheat bran and wheat flour) and sewage sludge performed from a food industry wastewater treatment station (vegetable oil plant), are presented. The research results demonstrated that the simultaneous EB and MW irradiation produces the biggest reduction of microorganisms. The tests also demonstrated that the irradiation time and the upper limit of required EB absorbed dose, which ensures a complete sterilization effect, could be reduced by a factor of two by an additional use of MW energy to EB irradiation

Beam-width spreading of vortex beams in free space

Science.gov (United States)

Wang, Weiwei; Li, Jinhong; Duan, Meiling

2018-01-01

Based on the extended Huygens-Fresnel principle and the definition of second-order moments of the Wigner distribution function, the analytical expression for the beam-width spreading of Gaussian Schell-model (GSM) vortex beams in free space are derived, and used to study the influence of beam parameters on the beam-width spreading of GSM vortex beams. With the increment of the propagation distance, the beam-width spreading of GSM vortex beams will increase; the bigger the topological charge, spatial correlation length, wavelength and waist width are, the smaller the beam-width spreading is.

Computation of beam quality parameters for Mo/Mo, Mo/Rh, Rh/Rh, and W/Al target/filter combinations in mammography

International Nuclear Information System (INIS)

Kharrati, Hedi; Zarrad, Boubaker

2003-01-01

A computer program was implemented to predict mammography x-ray beam parameters in the range 20-40 kV for Mo/Mo, Mo/Rh, Rh/Rh, and W/Al target/filter combinations. The computation method used to simulate mammography x-ray spectra is based on the Boone et al. model. The beam quality parameters such as the half-value layer (HVL), the homogeneity coefficient (HC), and the average photon energy were computed by simulating the interaction of the spectrum photons with matter. The checking of this computation was done using a comparison of the results with published data and measured values obtained at the Netherlands Metrology Institute Van Swinden Laboratorium, National Institute of Standards and Technology, and International Atomic Energy Agency. The predicted values with a mean deviation of 3.3% of HVL, 3.7% of HC, and 1.5% of average photon energy show acceptable agreement with published data and measurements for all target/filter combinations in the 23-40 kV range. The accuracy of this computation can be considered clinically acceptable and can allow an appreciable estimation for the beam quality parameters

Alanine-EPR dosimetry in 10 MeV electron beam to optimize process parameters for food irradiation

International Nuclear Information System (INIS)

Sanyal, B.; Kumar, S.; Kumar, M.; Mittal, K.C.; Sharma, A.

2011-01-01

Absorbed dose in a food product is determined and controlled by several components of the LINAC irradiation facility as well as the product. Standardization of the parameters characterizing the facility components, process load and the irradiation conditions collectively termed as 'process parameters' are of paramount importance for successful dose delivery to the food products. In the present study alanine-EPR dosimetry system was employed to optimize the process parameters of 10 MeV electron beam of a LINAC facility for commercial irradiation of food. Three sets of experiments were carried out with different food commodities namely, mango, potato and rawa with the available product conveying system of different irradiation geometry like one sided or both sided mode of irradiation. Three dimensional dose distributions into the process load for low dose requiring food commodities (0.25 to 1 kGy) were measured in each experiment. The actual depth dose profile in food product and useful scan width of the electron beam were found out to be satisfactory for commercial radiation processing of food. Finally a scaled up experiment with commercial food product (packets of Rawa) exhibited adequate dose uniformity ratio of 3 proving the feasibility of the facility for large scale radiation processing of food commodities. (author)

Beam-centric algorithm for pretreatment patient position correction in external beam radiation therapy

International Nuclear Information System (INIS)

Bose, Supratik; Shukla, Himanshu; Maltz, Jonathan

2010-01-01

Purpose: In current image guided pretreatment patient position adjustment methods, image registration is used to determine alignment parameters. Since most positioning hardware lacks the full six degrees of freedom (DOF), accuracy is compromised. The authors show that such compromises are often unnecessary when one models the planned treatment beams as part of the adjustment calculation process. The authors present a flexible algorithm for determining optimal realizable adjustments for both step-and-shoot and arc delivery methods. Methods: The beam shape model is based on the polygonal intersection of each beam segment with the plane in pretreatment image volume that passes through machine isocenter perpendicular to the central axis of the beam. Under a virtual six-DOF correction, ideal positions of these polygon vertices are computed. The proposed method determines the couch, gantry, and collimator adjustments that minimize the total mismatch of all vertices over all segments with respect to their ideal positions. Using this geometric error metric as a function of the number of available DOF, the user may select the most desirable correction regime. Results: For a simulated treatment plan consisting of three equally weighted coplanar fixed beams, the authors achieve a 7% residual geometric error (with respect to the ideal correction, considered 0% error) by applying gantry rotation as well as translation and isocentric rotation of the couch. For a clinical head-and-neck intensity modulated radiotherapy plan with seven beams and five segments per beam, the corresponding error is 6%. Correction involving only couch translation (typical clinical practice) leads to a much larger 18% mismatch. Clinically significant consequences of more accurate adjustment are apparent in the dose volume histograms of target and critical structures. Conclusions: The algorithm achieves improvements in delivery accuracy using standard delivery hardware without significantly increasing

Torsional Post-Buckling of a Simply Supported Thin-Walled Open-Section Beam Resting on a Two-Parameter Foundation

Science.gov (United States)

Rao, Ch. K.; Rao, L. B.

2018-01-01

The problem of the post-buckling response of a simply supported thin-walled beam subjected to an axial compressive load and supported by the Winkler-Pasternak foundation is studied in this paper. The strains are assumed to be small and elastic. The shear deformations and the in-plane cross-sectional deformations are assumed to be negligible. The post-buckling paths of the simply supported beam are determined for different values of the Winkler and Pasternak stiffness parameters. Bifurcation points are found.

Ultrasonic Beam Propagation in Highly Anisotropic Materials Simulated by Multi-Gaussian Beams

International Nuclear Information System (INIS)

Jeong, Hyun Jo; Schmerr, Lester W.

2007-01-01

The necessity of nondestructively inspecting fiber-reinforced composites, austenitic steels, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface play key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasi longitudinal (qL) beam propagates in the symmetry plane of a transversely isotropic gr/ep composite. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions

The measurement, control, and validation of critical parameters in an electron beam sterilization facility

International Nuclear Information System (INIS)

Burns, P.; Drewell, N.H.; McKeown, J.

1996-01-01

The delivery and validation of a specified dose to a medical device are key concerns of operators of electron beam irradiation facilities. In an IMPELA-based irradiator, four of the parameters that directly influence the absorbed dose distribution in the product are controllable in real time - the electron energy, average beam current, scanned area, and the product exposure time. The 10 MeV accelerator operates at 50 kW with a stream of 200 μs wide, 100 mA pulses at a repetition rate of 250 Hz. The combination of short-term intra-pulse regulation with long-term pulse-to-pulse stability makes the IMPELA output attractive for the sterilization of medical products. The measurement and closed-loop control techniques used in the IMPELA design will be described with reference to facilitating compliance with medical sterilization standards. (orig.)

Beam-Beam Interaction Studies at LHC

CERN Document Server

Schaumann, Michaela; Alemany Fernandez, R

2011-01-01

The beam-beam force is one of the most important limiting factors in the performance of a collider, mainly in the delivered luminosity. Therefore, it is essential to measure the effects in LHC. Moreover, adequate understanding of LHC beam-beam interaction is of crucial importance in the design phases of the LHC luminosity upgrade. Due to the complexity of this topic the work presented in this thesis concentrates on the beam-beam tune shift and orbit effects. The study of the Linear Coherent Beam-Beam Parameter at the LHC has been determined with head-on collisions with small number of bunches at injection energy (450 GeV). For high bunch intensities the beam-beam force is strong enough to expect orbit effects if the two beams do not collide head-on but with a crossing angle or with a given offset. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are as well ...

Industrial wastewater treatment with electron beam

Energy Technology Data Exchange (ETDEWEB)

Han, Bumsoo; Ko, Jaein; Kim, Jinkyu; Kim, Yuri; Chung, Wooho [Central Research Institute of Samsung Heavy Industries Co., Taejon (Korea)

2001-03-01

Global withdrawals of water to satisfy human demands have grown dramatically in this century. Between 1900 and 1945, water consumption increased by over six times, more than double the rate of population growth. This rapid growth in water demand is due to the increasing reliance on irrigation to achieve food security, the growth of industrial uses, and the increasing use per capita for domestic purposes. Given the seriousness of the situation and future risk of crises, there is an urgent need to develop the water-efficient technologies including economical treatment methods of wastewater and polluted water. In the Central Research Institute of Samsung Heavy Industries (SHI), many industrial wastewater including leachate from landfill area, wastewater from papermill, dyeing complex, petrochemical processes, etc. are under investigation with electron beam irradiation. For the study of treating dyeing wastewater combined with conventional facilities, an electron beam pilot plant for treating 1,000m{sup 3}/day of wastewater from 80,000m{sup 3}/day of total dyeing wastewater has constructed and operated in Taegu Dyeing Industrial Complex. A commercial plant for re-circulation of wastewater from Papermill Company is also designed for S-paper Co. in Cheongwon City, and after the successful installation, up to 80% of wastewater could be re-used in paper producing process. (author)

Industrial wastewater treatment with electron beam

International Nuclear Information System (INIS)

Han, Bumsoo; Ko, Jaein; Kim, Jinkyu; Kim, Yuri; Chung, Wooho

2001-01-01

Global withdrawals of water to satisfy human demands have grown dramatically in this century. Between 1900 and 1945, water consumption increased by over six times, more than double the rate of population growth. This rapid growth in water demand is due to the increasing reliance on irrigation to achieve food security, the growth of industrial uses, and the increasing use per capita for domestic purposes. Given the seriousness of the situation and future risk of crises, there is an urgent need to develop the water-efficient technologies including economical treatment methods of wastewater and polluted water. In the Central Research Institute of Samsung Heavy Industries (SHI), many industrial wastewater including leachate from landfill area, wastewater from papermill, dyeing complex, petrochemical processes, etc. are under investigation with electron beam irradiation. For the study of treating dyeing wastewater combined with conventional facilities, an electron beam pilot plant for treating 1,000m 3 /day of wastewater from 80,000m 3 /day of total dyeing wastewater has constructed and operated in Taegu Dyeing Industrial Complex. A commercial plant for re-circulation of wastewater from Papermill Company is also designed for S-paper Co. in Cheongwon City, and after the successful installation, up to 80% of wastewater could be re-used in paper producing process. (author)

Beam tuning parameters for the Kolkata superconducting cyclotron

International Nuclear Information System (INIS)

Debnath, J.; Dey, M.K.; Paul, S.; Pradhan, J.; Bhunia, U.; Dutta, A.; Agrawal, A.; Naser, Md. Z.A.; Rashid, M.H.; Mallik, C.; Bhandari, R.K.

2009-01-01

The internal beam tuning in the Superconducting cyclotron at VECC will be started very soon. The magnetic field data has been used to explore the beam dynamical issues. There are two main coils and fourteen no. of trim coils. The optimised main coil and trim coil current settings for producing the required near-isochronous field fitting suitable phase-energy curve to accelerate different ion species in the operating region with minimum trim coil power as well as minimum error in the energy-phase curve have been calculated and reported here. The equilibrium orbit properties i.e., the radial and axial focusing frequencies, frequency error, integrated phase shift etc. have been studied. The important issues related to beam deliverables are explored. (author)

Treatment planning for heavy ion radiotherapy: physical beam model and dose optimization

International Nuclear Information System (INIS)

Kraemer, M.; Haberer, T.; Kraft, G.; Schardt, D.; Weber, U.

2000-09-01

We describe a novel code system, TRiP, dedicated to the planning of radiotherapy with energetic ions, in particular 12 C. The software is designed to cooperate with three-dimensional active dose shaping devices like the GSI raster scan system. This unique beam delivery system allows to select any combination from a list of 253 individual beam energies, 7 different beam spot sizes and 15 intensity levels. The software includes a beam model adapted to and verified for carbon ions. Inverse planning techniques are implemented in order to obtain a uniform target dose distribution from clinical input data, i.e. CT images and patient contours. This implies the automatic generation of intensity modulated fields of heavy ions with as many as 40000 raster points, where each point corresponds to a specific beam position, energy and particle fluence. This set of data is directly passed to the beam delivery and control system. The treatment planning code is in clinical use since the start of the GSI pilot project in December 1997. To this end 48 patients have been successfully planned and treated. (orig.)

Treatment planning for heavy-ion radiotherapy: physical beam model and dose optimization

Science.gov (United States)

Krämer, M.; Jäkel, O.; Haberer, T.; Kraft, G.; Schardt, D.; Weber, U.

2000-11-01

We describe a novel code system, TRiP, dedicated to the planning of radiotherapy with energetic ions, in particular 12C. The software is designed to cooperate with three-dimensional active dose shaping devices like the GSI raster scan system. This unique beam delivery system allows us to select any combination from a list of 253 individual beam energies, 7 different beam spot sizes and 15 intensity levels. The software includes a beam model adapted to and verified for carbon ions. Inverse planning techniques are implemented in order to obtain a uniform target dose distribution from clinical input data, i.e. CT images and patient contours. This implies the automatic generation of intensity modulated fields of heavy ions with as many as 40 000 raster points, where each point corresponds to a specific beam position, energy and particle fluence. This set of data is directly passed to the beam delivery and control system. The treatment planning code has been in clinical use since the start of the GSI pilot project in December 1997. Forty-eight patients have been successfully planned and treated.

Development of electron beam flue gas treatment technology

International Nuclear Information System (INIS)

Tanaka, T.

1995-01-01

The electron beam flue gas treatment technology is expected to bring many advantages such as the simultaneous reduction of SO x and NO x emissions, a dry process without waste water, valuable fertilizer byproducts, etc. In order to verify the feasibility and performances of the process, a practical application test is carried out with a pilot plant which treats the actual flue gas from a coal-fired boiler. Results are presented. 4 figs., 2 tabs

Free vibration analysis of a cracked shear deformable beam on a two-parameter elastic foundation using a lattice spring model

Science.gov (United States)

Attar, M.; Karrech, A.; Regenauer-Lieb, K.

2014-05-01

The free vibration of a shear deformable beam with multiple open edge cracks is studied using a lattice spring model (LSM). The beam is supported by a so-called two-parameter elastic foundation, where normal and shear foundation stiffnesses are considered. Through application of Timoshenko beam theory, the effects of transverse shear deformation and rotary inertia are taken into account. In the LSM, the beam is discretised into a one-dimensional assembly of segments interacting via rotational and shear springs. These springs represent the flexural and shear stiffnesses of the beam. The supporting action of the elastic foundation is described also by means of normal and shear springs acting on the centres of the segments. The relationship between stiffnesses of the springs and the elastic properties of the one-dimensional structure are identified by comparing the homogenised equations of motion of the discrete system and Timoshenko beam theory.

Synthesis of Beam Lines with Necessary Properties

CERN Document Server

Andrianov, Serge

2005-01-01

In this paper a new approach to the problem of synthesis of beam lines is discussed. Usually this problem can be overcome by the use of numerical simulation and optimal control theory methods. But this results in sufficiently great number of variable parameters and functions. Obviously, that this degrades quality of a modeling procedure. The suggested approach is demonstrated on a problem of a microprobe design problem. Essence of the problem is that necessary to design a high precision focusing system which satisfies some additional conditions. For solution of this problem we use an algebraic treatment based on Lie algebraic methods and computer algebra techniques. Using the symmetry ideology this approach allows rewriting beam properties to enough simple conditions for control parameters and functions. This leads a set of desired solutions and show results in some most suitable form. Moreover, this approach decreases the number of variable parameters.

The effect of plasma parameter on the bootstrap current of fast ions in neutral beam injection

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Cao Jinjia; Yang Lei

2014-01-01

The effect of plasma parameters on the distribution of net current density of fast ions produced by neutral beam injection is investigated in a large-aspect-ratio Tokamak with circular cross-section under specific parameters. Numerical results show that the value of net current density increases with the temperature of plasma increasing and decreases with the density of plasma increasing. The value of net current density is weakly affected by the effective charge number, but the peak of net current density moves towards edge plasma with effective charge number increasing. (authors)

Future e+e- linear colliders and beam-beam effects

International Nuclear Information System (INIS)

Wilson, P.B.

1986-05-01

Numerous concepts, ranging from conventional to highly exotic, hae been proposed for the acceleration of electrons and positrons to very high energies. For any such concept to be viable, it must be possible to produce from it a set of consistent parameters for one of these ''benchmark'' machines. Attention is directed to the choice of parameters for a collider in the 300 GeV energy range, operating at a gradient on the order of 200 MV/m, using X-band power sources to drive a conventional disk-loaded accelerating structure. These rf power sources, while not completely conventional represent a reasonable extrapolation from present technology. The choice of linac parameters is strongly coupled to various beam-beam effects which take place when the electron and positron bunches collide. We summarize these beam-beam effects, and then return to the rf design of a 650 GeV center-of-mass collider. 14 refs

Parameter selection in limited data cone-beam CT reconstruction using edge-preserving total variation algorithms

Science.gov (United States)

Lohvithee, Manasavee; Biguri, Ander; Soleimani, Manuchehr

2017-12-01

There are a number of powerful total variation (TV) regularization methods that have great promise in limited data cone-beam CT reconstruction with an enhancement of image quality. These promising TV methods require careful selection of the image reconstruction parameters, for which there are no well-established criteria. This paper presents a comprehensive evaluation of parameter selection in a number of major TV-based reconstruction algorithms. An appropriate way of selecting the values for each individual parameter has been suggested. Finally, a new adaptive-weighted projection-controlled steepest descent (AwPCSD) algorithm is presented, which implements the edge-preserving function for CBCT reconstruction with limited data. The proposed algorithm shows significant robustness compared to three other existing algorithms: ASD-POCS, AwASD-POCS and PCSD. The proposed AwPCSD algorithm is able to preserve the edges of the reconstructed images better with fewer sensitive parameters to tune.

Treatment of liquid separated from sludge by the method using electron beam and ozone in combination

International Nuclear Information System (INIS)

Hosono, Masakazu; Arai, Hidehiko; Aizawa, Masaki; Shimooka, Toshio; Shimizu, Ken; Sugiyama, Masashi.

1995-01-01

Since the liquid separated from sludge in the dehydration or concentration process of sewer sludge contains considerable amount of organic compositions that are hard to be decomposed by microorganisms, it has become difficult to be treated by conventional activated sludge process. In the case of discharging the separated liquid into closed water areas, the higher quality treatment is required. The method of using electron beam irradiation and ozone oxidation in combination for cleaning the liquid separated from sludge was examined, therefore, the results are reported. The water quality of the sample from the sludge treatment plant in A City is shown. The method of bio-pretreatment, the treatment method by using electron beam and ozone in combination, and the method of analyzing the water quality are described. The effect of the treatment by activated sludge process, as the effect of the treatment by the combined use of electron beam and ozone, the change of COD and TOC, the change of chromaticity, the change of gel chromatogram, and the reaction mechanism are reported. In this paper, only the basic concept on the model plant for applying the method of the combined use of electron beam and ozone to the treatment of the liquid separated from sludge is discussed. (K.I.)

Electron Beam Diagnostics in Plasmas Based on Electron Beam Ionization

Science.gov (United States)

Leonhardt, Darrin; Leal-Quiros, Edbertho; Blackwell, David; Walton, Scott; Murphy, Donald; Fernsler, Richard; Meger, Robert

2001-10-01

Over the last few years, electron beam ionization has been shown to be a viable generator of high density plasmas with numerous applications in materials modification. To better understand these plasmas, we have fielded electron beam diagnostics to more clearly understand the propagation of the beam as it travels through the background gas and creates the plasma. These diagnostics vary greatly in sophistication, ranging from differentially pumped systems with energy selective elements to metal 'hockey pucks' covered with thin layers of insulation to electrically isolate the detector from the plasma but pass high energy beam electrons. Most importantly, absolute measurements of spatially resolved beam current densities are measured in a variety of pulsed and continuous beam sources. The energy distribution of the beam current(s) will be further discussed, through experiments incorporating various energy resolving elements such as simple grids and more sophisticated cylindrical lens geometries. The results are compared with other experiments of high energy electron beams through gases and appropriate disparities and caveats will be discussed. Finally, plasma parameters are correlated to the measured beam parameters for a more global picture of electron beam produced plasmas.

Fan-beam intensity modulated proton therapy.

Science.gov (United States)

Hill, Patrick; Westerly, David; Mackie, Thomas

2013-11-01

This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques. A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0-255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets. Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage. Overall, the sharp distal

Study of the Hollow Waveguides Physical Parameters Determined the Beam Shape Conservation of the Delivered Radiation

International Nuclear Information System (INIS)

Ben-David, M.; Inberg, A.; Katzir, A.; Croitoru, N.

1999-01-01

The modification of the laser source beam quality is one of the important factors effect the delivery of laser radiation by a waveguide. In this paper the results of input radiation coupling, radius of bending, length, cross section diameter, waveguide internal wall roughness and coupling lens focal length influence on the beam shape delivered from the flexible hollow waveguides are presented. The conditions for which the beam shape is near to that of the source were found. A theoretical model for the radiation propagation gives quantitative representation of relation between attenuation, beam profile, divergence and above indicated parameters was developed. In this model was supposed that the guiding is produced by multiple incidences on a metal (silver) layer and a dielectric (silver iodine) over layer, by refraction and reflection. The propagation of the rays was calculated using the physical laws of the geometrical optics. For the scattering calculations a random distribution of roughness centers on dielectric layer surface was considered. It was also supposed that the value of the cross section internal diameter (ID=d) was much larger than the transmitted wavelength. The experimental results have shown that losses due to absorption of the propagated radiation in the guiding layers, mainly (AgI), generate satellites of the laser source delivered fundamental Gaussian beam. Increasing of the hollow waveguide internal diameter decreases the attenuation and increases the deviation of beam shape from Gaussian. Off center coupling produce decreasing of the fundamental mode height and generation of the coupled Gaussian beam satellites. The waveguide internal wall roughness produce losses of the coupled radiation and beam profile deviations from that of the laser source. A good correspondence between the theoretical and experimental results obtained

On beam quality and flatness of radiotherapy megavoltage photon beams

International Nuclear Information System (INIS)

Hossain, Murshed; Rhoades, Jeffrey

2016-01-01

Ratio of percentage depth dose (PDD) at two depths, PDD at a depth of 10 cm (PDD 10 ), and beam flatness are monitored regularly for radiotherapy beams for quality assurance. The purpose of this study is to understand the effects of changes in one of these parameters on the other. Is it possible to monitor only the beam flatness and not PDD? The investigation has two components. Naturally occurring i.e., unintended changes in PDD ratio and in-plane flatness for 6 and 10 MV photon beams for one particular Siemens Artiste Linac are monitored for a period of about 4 years. Secondly, deliberate changes in the beam parameters are induced by changing the bending magnet current (BMI). Relationships between various beam parameters for unintended changes as well as deliberate changes are characterized. Long term unintentional changes of PDD ratio are found to have no systematic trend. The flatness in the in plane direction for 6 and 10 MV beams show slow increase of 0.43 and 0.75 % respectively in about 4 years while the changes in the PDD ratio show no such trend. Over 10 % changes in BMI are required to induce changes in the beam quality indices at 2 % level. PDD ratio for the 10 MV beam is found to be less sensitive, while the depth of maximum dose, d max , is more sensitive to the changes in BMI compared to the 6 MV beam. Tolerances are more stringent for PDD 10 than PDD ratio for the 10 MV beam. PDD ratio, PDD 10 , and flatness must be monitored independently. Furthermore, off axis ratio alone cannot be used to monitor flatness. The effect of beam quality change in the absolute dose is clinically insignificant.

The influence of beam divergence on ion-beam induced surface patterns

International Nuclear Information System (INIS)

Kree, R.; Yasseri, T.; Hartmann, A.K.

2009-01-01

We present a continuum theory and a Monte Carlo model of self-organized surface pattern formation by ion-beam sputtering including effects of beam profiles. Recently, it has turned out that such secondary ion-beam parameters may have a strong influence on the types of emerging patterns. We first discuss several cases, for which beam profiles lead to random parameters in the theory of pattern formation. Subsequently we study the evolution of the averaged height profile in continuum theory and find that the typical Bradley-Harper scenario of dependence of ripple patterns on the angle of incidence can be changed qualitatively. Beam profiles are implemented in Monte Carlo simulations, where we find generic effects on pattern formation. Finally, we demonstrate that realistic beam profiles, taken from experiments, may lead to qualitative changes of surface patterns.

Characterization of the Li beam probe with a beam profile monitor on JET.

Science.gov (United States)

Nedzelskiy, I S; Korotkov, A; Brix, M; Morgan, P; Vince, J

2010-10-01

The lithium beam probe (LBP) is widely used for measurements of the electron density in the edge plasma of magnetically confined fusion experiments. The quality of LBP data strongly depends on the stability and profile shape of the beam. The main beam parameters are as follows: beam energy, beam intensity, beam profile, beam divergence, and the neutralization efficiency. For improved monitoring of the beam parameters, a beam profile monitor (BPM) from the National Electrostatics Corporation (NEC) has been installed in the Li beam line at JET. In the NEC BPM, a single grounded wire formed into a 45° segment of a helix is rotated by a motor about the axis of the helix. During each full revolution, the wire sweeps twice across the beam to give X and Y profiles. In this paper, we will describe the properties of the JET Li beam as measured with the BPM and demonstrate that it facilitates rapid optimization of the gun performance.

Focusing of high power ultrasound beams and limiting values of shock wave parameters

Science.gov (United States)

Bessonova, O. V.; Khokhlova, V. A.; Bailey, M. R.; Canney, M. S.; Crum, L. A.

2009-10-01

In this work, the influence of nonlinear and diffraction effects on amplification factors of focused ultrasound systems is investigated. The limiting values of acoustic field parameters obtained by focusing of high power ultrasound are studied. The Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation was used for the numerical modeling. Solutions for the nonlinear acoustic field were obtained at output levels corresponding to both pre- and post-shock formation conditions in the focal area of the beam in a weakly dissipative medium. Numerical solutions were compared with experimental data as well as with known analytic predictions.

Basic research on flue gas smoke treatment by electron beam

International Nuclear Information System (INIS)

Namba, Hideki

1995-01-01

Recently, accompanying the increase of the use of fossil fuel, the environment destruction due to the sulfur oxides and nitrogen oxides contained in combustion smoke has become a serious problem. The development of flue gas smoke treatment technology by using electron beam was started in Japan, and attention has been paid worldwide as the promising dry type simultaneous desulfurizing and denitrating process. In this process, by adding ammonia to smoke, and irradiating electron beam on it, ammonium nitrate and ammonium sulfate are formed. As to the reaction mechanism of denitration and desulfurization, radical formation, radical reaction, denitration mechanism, desulfurization mechanism, the particle size distribution of the formed aerosol, the amounts of denitration and desulfurization by electron beam smoke treatment process, the improvement of the denitration efficiency by multi-stage irradiation method and the improvement of the desulfurization rate by low temperature irradiation, and the basic test toward the pilot test are explained. The basic research for putting this system to practical use was carried out jointly by Japan Atomic Energy Research Institute, Chubu Electric Power Co., Inc., and Ebara Seisakusho for standard coal burning smoke in Japan. The verifying test at the pilot plant in Shinnagoya Thermal Power Station was carried out, and it was verified that this process can be used practically for treating coal-burning smoke. (K.I.)

Heavy particle beam cancer treatment apparatus, HIMAC, and clinical trial

International Nuclear Information System (INIS)

Soga, Fuminori

1994-01-01

The clinical trial was begun in June, 1994, on the treatment of cancer patients using heavy particle beam for the first time in Japan in National Institute of Radiological Sciences. It is the result of promoting the construction of Heavy Ion Medical Accelerator in Chiba (HIMAC) with the first period construction cost of 32.6 billion yen as a part of the 10 year general strategy against cancer. This is only one facility of this kind in the world. The features of heavy particle beam as radiation therapy are the excellent concentration of dose distribution, biological effect and so on. The nuclides to be used are those having the atomic number from helium to argon. The acceleration energy of ions was set at 800 MeV per nucleon so as to reach 30 cm in human bodies. The beam intensity is 5 Gy/min to finish irradiation within 1 min. The maximum irradiation field is 22 cm in diameter. The specification of the HIMAC accelerator is summarized. The Penning Ionization Gauge and the electron cyclotron resonance ion sources were installed for the reliability. The radio frequency quadrupole linear accelerator is suitable to accelerate low velocity, high intensity beam. Two synchrotrons of 41 m mean diameter are installed. High energy beam transport system, irradiation equipment, and the clinical trial are reported. (K.I.)

Consistency checks in beam emission modeling for neutral beam injectors

International Nuclear Information System (INIS)

Punyapu, Bharathi; Vattipalle, Prahlad; Sharma, Sanjeev Kumar; Baruah, Ujjwal Kumar; Crowley, Brendan

2015-01-01

In positive neutral beam systems, the beam parameters such as ion species fractions, power fractions and beam divergence are routinely measured using Doppler shifted beam emission spectrum. The accuracy with which these parameters are estimated depend on the accuracy of the atomic modeling involved in these estimations. In this work, an effective procedure to check the consistency of the beam emission modeling in neutral beam injectors is proposed. As a first consistency check, at a constant beam voltage and current, the intensity of the beam emission spectrum is measured by varying the pressure in the neutralizer. Then, the scaling of measured intensity of un-shifted (target) and Doppler shifted intensities (projectile) of the beam emission spectrum at these pressure values are studied. If the un-shifted component scales with pressure, then the intensity of this component will be used as a second consistency check on the beam emission modeling. As a further check, the modeled beam fractions and emission cross sections of projectile and target are used to predict the intensity of the un-shifted component and then compared with the value of measured target intensity. An agreement between the predicted and measured target intensities provide the degree of discrepancy in the beam emission modeling. In order to test this methodology, a systematic analysis of Doppler shift spectroscopy data obtained on the JET neutral beam test stand data was carried out

Influence of physical and chemical parameters on the irradiation of aqueous solutions of phenol by electron beam

International Nuclear Information System (INIS)

Pellizzari, Fabien

2005-01-01

The aim of this work was the study of the influence of different parameters by electron beam irradiation on the decomposition of phenol in aqueous solution. A simulation based on a simplified mechanism emphasized the importance of the oxygenation of the solutions in the removal of phenol by ionisation. A model of the reactor used was proposed from the study of the influence of the beam energy on the decomposition of phenol. Penetration depths of the electrons were determined. Phenol degradation was found to increase with the dose rate. The fraction of the dose into several passages under the electron beam improved the abatement of the phenol. The reoxygenation of the solutions between each passage and the kinetic expressions of irradiation could explain this effect. As expected, the first by-products identified were originated from the reaction of phenol with hydroxyl radicals. [fr

Image-guided radiotherapy in near real time with intensity-modulated radiotherapy megavoltage treatment beam imaging.

Science.gov (United States)

Mao, Weihua; Hsu, Annie; Riaz, Nadeem; Lee, Louis; Wiersma, Rodney; Luxton, Gary; King, Christopher; Xing, Lei; Solberg, Timothy

2009-10-01

To utilize image-guided radiotherapy (IGRT) in near real time by obtaining and evaluating the online positions of implanted fiducials from continuous electronic portal imaging device (EPID) imaging of prostate intensity-modulated radiotherapy (IMRT) delivery. Upon initial setup using two orthogonal images, the three-dimensional (3D) positions of all implanted fiducial markers are obtained, and their expected two-dimensional (2D) locations in the beam's-eye-view (BEV) projection are calculated for each treatment field. During IMRT beam delivery, EPID images of the megavoltage treatment beam are acquired in cine mode and subsequently analyzed to locate 2D locations of fiducials in the BEV. Simultaneously, 3D positions are estimated according to the current EPID image, information from the setup portal images, and images acquired at other gantry angles (the completed treatment fields). The measured 2D and 3D positions of each fiducial are compared with their expected 2D and 3D setup positions, respectively. Any displacements larger than a predefined tolerance may cause the treatment system to suspend the beam delivery and direct the therapists to reposition the patient. Phantom studies indicate that the accuracy of 2D BEV and 3D tracking are better than 1 mm and 1.4 mm, respectively. A total of 7330 images from prostate treatments were acquired and analyzed, showing a maximum 2D displacement of 6.7 mm and a maximum 3D displacement of 6.9 mm over 34 fractions. This EPID-based, real-time IGRT method can be implemented on any external beam machine with portal imaging capabilities without purchasing any additional equipment, and there is no extra dose delivered to the patient.

Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer

Energy Technology Data Exchange (ETDEWEB)

Steel, Jared; Stewart, Allan; Satory, Philip [Auckland Regional Blood and Cancer Service, Auckland City Hospital, 2 Park Road, Grafton, Auckland 1023 (New Zealand)

2009-09-15

Purpose: Matching the penumbra of a 6 MeV electron beam to the penumbra of a 6 MV photon beam is a dose optimization challenge, especially when the electron beam is applied from an extended source-to-surface distance (SSD), as in the case of some head and neck treatments. Traditionally low melting point alloy blocks have been used to define the photon beam shielding over the spinal cord region. However, these are inherently time consuming to construct and employ in the clinical situation. Multileaf collimators (MLCs) provide a fast and reproducible shielding option but generate geometrically nonconformal approximations to the desired beam edge definition. The effects of substituting Cerrobend for the MLC shielding mode in the context of beam matching with extended-SSD electron beams are the subject of this investigation. Methods: Relative dose beam data from a Varian EX 2100 linear accelerator were acquired in a water tank under the 6 MeV electron beam at both standard and extended-SSD and under the 6 MV photon beam defined by Cerrobend and a number of MLC stepping regimes. The effect of increasing the electron beam SSD on the beam penumbra was assessed. MLC stepping was also assessed in terms of the effects on both the mean photon beam penumbra and the intraleaf dose-profile nonuniformity relative to the MLC midleaf. Computational techniques were used to combine the beam data so as to simulate composite relative dosimetry in the water tank, allowing fine control of beam abutment gap variation. Idealized volumetric dosimetry was generated based on the percentage depth-dose data for the beam modes and the abutment geometries involved. Comparison was made between each composite dosimetry dataset and the relevant ideal dosimetry dataset by way of subtraction. Results: Weighted dose-difference volume histograms (DDVHs) were produced, and these, in turn, summed to provide an overall dosimetry score for each abutment and shielding type/angle combination. Increasing the

Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer

International Nuclear Information System (INIS)

Steel, Jared; Stewart, Allan; Satory, Philip

2009-01-01

Purpose: Matching the penumbra of a 6 MeV electron beam to the penumbra of a 6 MV photon beam is a dose optimization challenge, especially when the electron beam is applied from an extended source-to-surface distance (SSD), as in the case of some head and neck treatments. Traditionally low melting point alloy blocks have been used to define the photon beam shielding over the spinal cord region. However, these are inherently time consuming to construct and employ in the clinical situation. Multileaf collimators (MLCs) provide a fast and reproducible shielding option but generate geometrically nonconformal approximations to the desired beam edge definition. The effects of substituting Cerrobend for the MLC shielding mode in the context of beam matching with extended-SSD electron beams are the subject of this investigation. Methods: Relative dose beam data from a Varian EX 2100 linear accelerator were acquired in a water tank under the 6 MeV electron beam at both standard and extended-SSD and under the 6 MV photon beam defined by Cerrobend and a number of MLC stepping regimes. The effect of increasing the electron beam SSD on the beam penumbra was assessed. MLC stepping was also assessed in terms of the effects on both the mean photon beam penumbra and the intraleaf dose-profile nonuniformity relative to the MLC midleaf. Computational techniques were used to combine the beam data so as to simulate composite relative dosimetry in the water tank, allowing fine control of beam abutment gap variation. Idealized volumetric dosimetry was generated based on the percentage depth-dose data for the beam modes and the abutment geometries involved. Comparison was made between each composite dosimetry dataset and the relevant ideal dosimetry dataset by way of subtraction. Results: Weighted dose-difference volume histograms (DDVHs) were produced, and these, in turn, summed to provide an overall dosimetry score for each abutment and shielding type/angle combination. Increasing the

Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer.

Science.gov (United States)

Steel, Jared; Stewart, Allan; Satory, Philip

2009-09-01

Matching the penumbra of a 6 MeV electron beam to the penumbra of a 6 MV photon beam is a dose optimization challenge, especially when the electron beam is applied from an extended source-to-surface distance (SSD), as in the case of some head and neck treatments. Traditionally low melting point alloy blocks have been used to define the photon beam shielding over the spinal cord region. However, these are inherently time consuming to construct and employ in the clinical situation. Multileaf collimators (MLCs) provide a fast and reproducible shielding option but generate geometrically nonconformal approximations to the desired beam edge definition. The effects of substituting Cerrobend for the MLC shielding mode in the context of beam matching with extended-SSD electron beams are the subject of this investigation. Relative dose beam data from a Varian EX 2100 linear accelerator were acquired in a water tank under the 6 MeV electron beam at both standard and extended-SSD and under the 6 MV photon beam defined by Cerrobend and a number of MLC stepping regimes. The effect of increasing the electron beam SSD on the beam penumbra was assessed. MLC stepping was also assessed in terms of the effects on both the mean photon beam penumbra and the intraleaf dose-profile nonuniformity relative to the MLC midleaf. Computational techniques were used to combine the beam data so as to simulate composite relative dosimetry in the water tank, allowing fine control of beam abutment gap variation. Idealized volumetric dosimetry was generated based on the percentage depth-dose data for the beam modes and the abutment geometries involved. Comparison was made between each composite dosimetry dataset and the relevant ideal dosimetry dataset by way of subtraction. Weighted dose-difference volume histograms (DDVHs) were produced, and these, in turn, summed to provide an overall dosimetry score for each abutment and shielding type/angle combination. Increasing the electron beam SSD increased

An Electron Beam Profile Instrument Based on FBGs

Directory of Open Access Journals (Sweden)

Dan Sporea

2014-08-01

Full Text Available Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/energy distribution in the beam are parameters of interest for charged particle accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transverse profile of the beam, its position, its centroid location, and its focus or flatness depend on the instrument operating conditions or on the beam exit setup. Proof-of-concept of a new type of charged particle beam diagnostics based on fiber Bragg gratings (FBGs was demonstrated. Its operating principle relies on the measurement of the peak wavelength changes for an array of FBG sensors as function of the temperature following the exposure to an electron beam. Periodically, the sensor irradiation is stopped and the FBG are force cooled to a reference temperature with which the temperature influencing each sensor during beam exposure is compared. Commercially available FBGs, and FBGs written in radiation resistant optical fibers, were tested under electron beam irradiation in order to study their possible use in this application.

Incorporating model parameter uncertainty into inverse treatment planning

International Nuclear Information System (INIS)

Lian Jun; Xing Lei

2004-01-01

Radiobiological treatment planning depends not only on the accuracy of the models describing the dose-response relation of different tumors and normal tissues but also on the accuracy of tissue specific radiobiological parameters in these models. Whereas the general formalism remains the same, different sets of model parameters lead to different solutions and thus critically determine the final plan. Here we describe an inverse planning formalism with inclusion of model parameter uncertainties. This is made possible by using a statistical analysis-based frameset developed by our group. In this formalism, the uncertainties of model parameters, such as the parameter a that describes tissue-specific effect in the equivalent uniform dose (EUD) model, are expressed by probability density function and are included in the dose optimization process. We found that the final solution strongly depends on distribution functions of the model parameters. Considering that currently available models for computing biological effects of radiation are simplistic, and the clinical data used to derive the models are sparse and of questionable quality, the proposed technique provides us with an effective tool to minimize the effect caused by the uncertainties in a statistical sense. With the incorporation of the uncertainties, the technique has potential for us to maximally utilize the available radiobiology knowledge for better IMRT treatment

Study of beam-beam long range compensation with octupoles

CERN Document Server

AUTHOR|(CDS)2068329; Pieloni, Tatiana; Buffat, Xavier; Tambasco, Claudia

2017-01-01

Long range beam-beam effects are responsible for particle losses and define fundamental operational parameters of colliders (i.e. crossing angles, intensities, emittances, ${\\beta}$${^∗}$). In this study we propose octuple magnets as a possible scheme to efficiently compensate long-range beam-beam interactions with a global correction scheme. The impact and improvements on the dynamic aperture of colliding beams together with estimates of the luminosity potentials are dis- cussed for the HL-LHC upgrade and extrapolations made for the FCC project.

Electron beam flue gas treatment. Research cooperation among JAERI, IAEA and INCT

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-10-01

The research co-operation is conducted among Japan Atomic Energy Research Institute (JAERI), International Atomic Energy Agency (IAEA) and Institute of Nuclear Chemistry and Technology in Poland (INCT) on Electron Beam Flue Gas Treatment from January 1993 to March 1997. The first phase of the cooperation was carried out for 3 years from January 1993 to March 1995. This cooperation was performed through information exchange meetings (Coordination Meetings), held in Takasaki and Warsaw, and experiments and discussions by exchange scientists. Many useful results were obtained on electron beam treatment of flue gas from coal-combustion heat generation plant in Kaweczyn within the frame work of the research co-operation. This report includes the main results of the tripartite research cooperation. (author)

SU-F-BRD-08: Guaranteed Epsilon-Optimal Treatment Plans with Minimum Number of Beams for SBRT Using RayStation

International Nuclear Information System (INIS)

Yarmand, H; Winey, B; Craft, D

2014-01-01

Purpose: To efficiently find quality-guaranteed treatment plans with the minimum number of beams for stereotactic body radiation therapy using RayStation. Methods: For a pre-specified pool of candidate beams we use RayStation (a treatment planning software for clinical use) to identify the deliverable plan which uses all the beams with the minimum dose to organs at risk (OARs) and dose to the tumor and other structures in specified ranges. Then use the dose matrix information for the generated apertures from RayStation to solve a linear program to find the ideal plan with the same objective and constraints allowing use of all beams. Finally we solve a mixed integer programming formulation of the beam angle optimization problem (BAO) with the objective of minimizing the number of beams while remaining in a predetermined epsilon-optimality of the ideal plan with respect to the dose to OARs. Since the treatment plan optimization is a multicriteria optimization problem, the planner can exploit the multicriteria optimization capability of RayStation to navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing quality. For the numerical experiments two liver cases and one lung case with 33 non-coplanar beams are considered. Results: The ideal plan uses an impractically large number of beams. The proposed technique reduces the number of beams to the range of practical application (5 to 9 beams) while remaining in the epsilon-optimal range of 1% to 5% optimality gap. Conclusion: The proposed method can be integrated into a general algorithm for fast navigation of the ideal dose distribution Pareto surface and finding the treatment plan with the minimum number of beams, which corresponds to the delivery time, in epsilon-optimality range of the desired ideal plan. The project was supported by the Federal Share of program income

SU-F-BRD-08: Guaranteed Epsilon-Optimal Treatment Plans with Minimum Number of Beams for SBRT Using RayStation

Energy Technology Data Exchange (ETDEWEB)

Yarmand, H; Winey, B; Craft, D [Massachusetts General Hospital, Boston, MA (United States)

2014-06-15

Purpose: To efficiently find quality-guaranteed treatment plans with the minimum number of beams for stereotactic body radiation therapy using RayStation. Methods: For a pre-specified pool of candidate beams we use RayStation (a treatment planning software for clinical use) to identify the deliverable plan which uses all the beams with the minimum dose to organs at risk (OARs) and dose to the tumor and other structures in specified ranges. Then use the dose matrix information for the generated apertures from RayStation to solve a linear program to find the ideal plan with the same objective and constraints allowing use of all beams. Finally we solve a mixed integer programming formulation of the beam angle optimization problem (BAO) with the objective of minimizing the number of beams while remaining in a predetermined epsilon-optimality of the ideal plan with respect to the dose to OARs. Since the treatment plan optimization is a multicriteria optimization problem, the planner can exploit the multicriteria optimization capability of RayStation to navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing quality. For the numerical experiments two liver cases and one lung case with 33 non-coplanar beams are considered. Results: The ideal plan uses an impractically large number of beams. The proposed technique reduces the number of beams to the range of practical application (5 to 9 beams) while remaining in the epsilon-optimal range of 1% to 5% optimality gap. Conclusion: The proposed method can be integrated into a general algorithm for fast navigation of the ideal dose distribution Pareto surface and finding the treatment plan with the minimum number of beams, which corresponds to the delivery time, in epsilon-optimality range of the desired ideal plan. The project was supported by the Federal Share of program income

Direct evaluation of radiobiological parameters from clinical data in the case of ion beam therapy: an alternative approach to the relative biological effectiveness

International Nuclear Information System (INIS)

Cometto, A; Russo, G; Giordanengo, S; Marchetto, F; Cirio, R; Attili, A; Bourhaleb, F; Milian, F M

2014-01-01

The relative biological effectiveness (RBE) concept is commonly used in treatment planning for ion beam therapy. Whether models based on in vitro/in vivo RBE data can be used to predict human response to treatments is an open issue. In this work an alternative method, based on an effective radiobiological parameterization directly derived from clinical data, is presented. The method has been applied to the analysis of prostate cancer trials with protons and carbon ions. Prostate cancer trials with proton and carbon ion beams reporting 5 year-local control (LC5) and grade 2 (G2) or higher genitourinary toxicity rates (TOX) were selected from literature to test the method. Treatment simulations were performed on a representative subset of patients to produce dose and linear energy transfer distribution, which were used as explicative physical variables for the radiobiological modelling. Two models were taken into consideration: the microdosimetric kinetic model (MKM) and a linear model (LM). The radiobiological parameters of the LM and MKM were obtained by coupling them with the tumor control probability and normal tissue complication probability models to fit the LC5 and TOX data through likelihood maximization. The model ranking was based on the Akaike information criterion. Results showed large confidence intervals due to the limited variety of available treatment schedules. RBE values, such as RBE = 1.1 for protons in the treated volume, were derived as a by-product of the method, showing a consistency with current approaches. Carbon ion RBE values were also derived, showing lower values than those assumed for the original treatment planning in the target region, whereas higher values were found in the bladder. Most importantly, this work shows the possibility to infer the radiobiological parametrization for proton and carbon ion treatment directly from clinical data. (paper)

Contribution to the planning and dosimetry of photon beams applied to radiosurgery and stereotactic radiotherapy

International Nuclear Information System (INIS)

Santos, Walter Menezes

2003-08-01

Radiosurgery and stereotactic radiotherapy are irradiation techniques that use small diameter photon beams for treating intracranial lesions such as pituitary adenomas, acoustic tumors and arterio-venous malformations which are inaccessible for surgery. These treatment techniques are characterized by the use of very small radiation beams which deliver a precisely measured dose to the target volume, while sparing the surrounding healthy tissue. Treatment can be performed by using multiple 60 Co gamma-ray sources (in the so-called 'Gamma Knife'), charged particles or X-ray beams produced by linear accelerators. The prescribed dose can be given in a single session or in multiple fractions, as in conventional radiotherapy. The success of the treatment depends, among other factors, of the accurate determination of the parameters that characterize the radiation beam produced by the equipment, as well as, of a well designed quality assurance program. In this study, the dosimetric parameters of a set of collimating cones of a Radionics TM treatment system applied to two 6 MV- photon beams (Clinac 600C - Varian TM , and Mevatron MD2 - Siemens TM ) were evaluated by using a water filled PMMA simulator. Measurements were carried out for photon beam diameters ranging from 12.5 to 40.0 mm for the Clinac-600C and from 5.0 to 50.0 mm for the Mevatron MD2. The parameters were evaluated by using a parallel plate ionization chamber (Markus), Kodak X-Omat V dosimetric films, thermoluminescent dosemeters (Harschaw, TLD-100) and photodiodes. The maximum tissue-ratio, the off-axis profile and the output factors were determined and the results were compared to those reported elsewhere. A study of the dosimetric characteristics of some commercially available phototransistors was also carried out. The results showed that these electronic components can be successfully used for measuring the dosimetric parameters of small diameter photon beans used in radiosurgery. Measurements were also

Electron beam processing programme: Wastewater and sludge treatment in Brazil

International Nuclear Information System (INIS)

Sampa, M.H.O.; Rela, P.R.; Duarte, C.L.; Borrely, S.I.; Vieira, J.M.

1998-01-01

The Institute for Energetic and Nuclear Research, working on environmental applications, has an extensive research programme using high energy electron beam in treating industrial wastewater and sludge. The experiments are being conducted in a pilot plant using an industrial electron beam 1.5MeV, 25mA, where the streams are presented to the scanned electron beam in counter flow. This pilot plant is designed to process approximately 3.0m 3 /h with an average dose 5kGy and the absorbed dose measurement is performed continuously by calorimetric system in real time. Combined biological and radiation treatment of domestic sewage and sludge were carried out to investigate disinfestation and removal of organic matter. The experiments showed that total and fecal coliforms were decreased by about 5 logs cycles with a 3.0kGy radiation dose in raw sewage and biological effluents, respectively. Concerning the industrial wastewater in the first stage of the programme, the irradiation was conducted using batch systems with samples originating from a Governmental Wastewater Treatment Plant. The data showed a significant color reduction effect when delivered dose was increased, and the opposite was noted for turbidity and total suspended solids. Other experiments were focused to process real industrial effluents from one of the most important chemical and pharmaceutical industries in Brazil. A special transport truck was used to transfer the liquid waste from the Industry to the Electron Beam Pilot Plant. Large quantities of liquid waste were irradiated with and without air addition with the doses from 2kGy to 20kGy. Such experiences performed in association with the Industry demonstrated that this technology has a great potential to be transferred and to contribute with a permanent cleanup alternative for hazardous wastes

Image-Guided Radiotherapy in Near Real Time With Intensity-Modulated Radiotherapy Megavoltage Treatment Beam Imaging

International Nuclear Information System (INIS)

Mao Weihua; Hsu, Annie; Riaz, Nadeem; Lee, Louis; Wiersma, Rodney; Luxton, Gary; King, Christopher; Xing Lei; Solberg, Timothy

2009-01-01

Purpose: To utilize image-guided radiotherapy (IGRT) in near real time by obtaining and evaluating the online positions of implanted fiducials from continuous electronic portal imaging device (EPID) imaging of prostate intensity-modulated radiotherapy (IMRT) delivery. Methods and Materials: Upon initial setup using two orthogonal images, the three-dimensional (3D) positions of all implanted fiducial markers are obtained, and their expected two-dimensional (2D) locations in the beam's-eye-view (BEV) projection are calculated for each treatment field. During IMRT beam delivery, EPID images of the megavoltage treatment beam are acquired in cine mode and subsequently analyzed to locate 2D locations of fiducials in the BEV. Simultaneously, 3D positions are estimated according to the current EPID image, information from the setup portal images, and images acquired at other gantry angles (the completed treatment fields). The measured 2D and 3D positions of each fiducial are compared with their expected 2D and 3D setup positions, respectively. Any displacements larger than a predefined tolerance may cause the treatment system to suspend the beam delivery and direct the therapists to reposition the patient. Results: Phantom studies indicate that the accuracy of 2D BEV and 3D tracking are better than 1 mm and 1.4 mm, respectively. A total of 7330 images from prostate treatments were acquired and analyzed, showing a maximum 2D displacement of 6.7 mm and a maximum 3D displacement of 6.9 mm over 34 fractions. Conclusions: This EPID-based, real-time IGRT method can be implemented on any external beam machine with portal imaging capabilities without purchasing any additional equipment, and there is no extra dose delivered to the patient.

Reconstruction of FXR Beam Conditions

International Nuclear Information System (INIS)

Nexen, W E; Scarpetti, R D; Zentler, J

2001-01-01

Beam-envelope radius, envelope angle, and beam emittance can be derived from measurements of beam radius for at least three different transport conditions. We have used this technique to reconstruct exit parameters from the FXR injector and accelerator. We use a diamagnetic loop (DML) to measure the magnetic moment of the high current beam. With no assumptions about radial profile, we can derive the beam mean squire radius from the moment under certain easily met conditions. Since it is this parameter which is required for the reconstruction, it is evident that the DML is the ideal diagnostic for this technique. The simplest application of this technique requires at least three shots for a reconstruction but in reality requires averaging over many more shots because of shot to shot variation. Since DML measurements do not interfere with the beam, single shot time resolved measurements of the beam parameters appear feasible if one uses an array of at least three DMLs separated by known transport conditions

Improved Beam Angle Arrangement in Intensity Modulated Proton Therapy Treatment Planning for Localized Prostate Cancer

International Nuclear Information System (INIS)

Cao, Wenhua; Lim, Gino J.; Li, Yupeng; Zhu, X. Ronald; Zhang, Xiaodong

2015-01-01

Purpose: This study investigates potential gains of an improved beam angle arrangement compared to a conventional fixed gantry setup in intensity modulated proton therapy (IMPT) treatment for localized prostate cancer patients based on a proof of principle study. Materials and Methods: Three patients with localized prostate cancer retrospectively selected from our institution were studied. For each patient, IMPT plans were designed using two, three and four beam angles, respectively, obtained from a beam angle optimization algorithm. Those plans were then compared with ones using two lateral parallel-opposed beams according to the conventional planning protocol for localized prostate cancer adopted at our institution. Results: IMPT plans with two optimized angles achieved significant improvements in rectum sparing and moderate improvements in bladder sparing against those with two lateral angles. Plans with three optimized angles further improved rectum sparing significantly over those two-angle plans, whereas four-angle plans found no advantage over three-angle plans. A possible three-beam class solution for localized prostate patients was suggested and demonstrated with preserved dosimetric benefits because individually optimized three-angle solutions were found sharing a very similar pattern. Conclusions: This study has demonstrated the potential of using an improved beam angle arrangement to better exploit the theoretical dosimetric benefits of proton therapy and provided insights of selecting quality beam angles for localized prostate cancer treatment

Static Magnetic Field Therapy: A Critical Review of Treatment Parameters

Directory of Open Access Journals (Sweden)

Agatha P. Colbert

2009-01-01

Full Text Available Static magnetic field (SMF therapy, applied via a permanent magnet attached to the skin, is used by people worldwide for self-care. Despite a lack of established SMF dosage and treatment regimens, multiple studies are conducted to evaluate SMF therapy effectiveness. Our objectives in conducting this review are to: (i summarize SMF research conducted in humans; (ii critically evaluate reporting quality of SMF dosages and treatment parameters and (iii propose a set of criteria for reporting SMF treatment parameters in future clinical trials. We searched 27 electronic databases and reference lists. Only English language human studies were included. Excluded were studies of electromagnetic fields, transcranial magnetic stimulation, magnets placed on acupuncture points, animal studies, abstracts, posters and editorials. Data were extracted on clinical indication, study design and 10 essential SMF parameters. Three reviewers assessed quality of reporting and calculated a quality assessment score for each of the 10 treatment parameters. Fifty-six studies were reviewed, 42 conducted in patient populations and 14 in healthy volunteers. The SMF treatment parameters most often and most completely described were site of application, magnet support device and frequency and duration of application. Least often and least completely described were characteristics of the SMF: magnet dimensions, measured field strength and estimated distance of the magnet from the target tissue. Thirty-four (61% of studies failed to provide enough detail about SMF dosage to permit protocol replication by other investigators. Our findings highlight the need to optimize SMF dosing parameters for individual clinical conditions before proceeding to a full-scale clinical trial.

Ion beam diagnosis

International Nuclear Information System (INIS)

Strehl, P.

1994-04-01

This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

SPIDER beam dump as diagnostic of the particle beam

Energy Technology Data Exchange (ETDEWEB)

Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E. [Università degli Studi di Padova, Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy); Dalla Palma, M.; Brombin, M.; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy)

2016-11-15

The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

Geant4 simulation for a study of a possible use of carbon ions pencil beam for the treatment of ocular melanomas with the active scanning system at CNAO Centre

International Nuclear Information System (INIS)

Farina, E.; Piersimoni, P.; Riccardi, C.; Rimoldi, A.; Tamborini, A.; Ciocca, M.

2015-01-01

The aim of this work is to validate the Geant4 application reproducing the CNAO (National Centre for Oncological Hadrontherapy) beamline and to study of a possible use of carbon ion pencil beams for the treatment of ocular melanomas at the CNAO Centre. The promising aspect of carbon ions radiotherapy for the treatment of this disease lies in its superior relative radiobiological effectiveness (RBE). The Monte Carlo Geant4 toolkit is used to simulate the complete CNAO extraction beamline, with the active and passive components along it. A human eye modeled detector, including a realistic target tumor volume, is used as target. Cross check with previous studies at CNAO using protons allows comparisons on possible benefits on using such a technique with respect to proton beams. Before the eye-detector irradiation a validation of the Geant4 simulation with CNAO experimental data is carried out with both carbon ions and protons. Important beam parameters such as the transverse FWHM and scanned radiation field 's uniformity are tested within the simulation and compared with experimental measurements at CNAO Centre. The physical processes involved in secondary particles generation by carbon ions and protons in the eye-detector are reproduced to take into account the additional dose to the primary beam given to irradiated eye's tissues. A study of beam shaping is carried out to produce a uniform 3D dose distribution (shaped on the tumor) by the use of a spread out Bragg peak. The eye-detector is then irradiated through a two dimensional transverse beam scan at different depths. In the use case the eye-detector is rotated of an angle of 40 deg. in the vertical direction, in order to mis-align the tumor from healthy tissues in front of it. The treatment uniformity on the tumor in the eye-detector is tested. For a more quantitative description of the deposited dose in the eye-detector and for the evaluation of the ratio between the dose deposited in the tumor and

Geant4 simulation for a study of a possible use of carbon ions pencil beam for the treatment of ocular melanomas with the active scanning system at CNAO Centre

Energy Technology Data Exchange (ETDEWEB)

Farina, E. [University of Pavia-Department of Physics, via Bassi 6, 27100 Pavia (Italy); Piersimoni, P. [Division of Radiation Research, Loma Linda University, Loma Linda, CA 92354 (United States); Riccardi, C.; Rimoldi, A.; Tamborini, A. [University of Pavia-Department of Physics, via Bassi 6, 27100 Pavia (Italy); INFN Section of Pavia, via Bassi 6, 27100 Pavia (Italy); Ciocca, M. [Medical Physics Unit, Centro Nazionale di Adroterapia Oncologica - CNAO Foundation, Strada Campeggi 53, 27100 Pavia (Italy)

2015-07-01

The aim of this work is to validate the Geant4 application reproducing the CNAO (National Centre for Oncological Hadrontherapy) beamline and to study of a possible use of carbon ion pencil beams for the treatment of ocular melanomas at the CNAO Centre. The promising aspect of carbon ions radiotherapy for the treatment of this disease lies in its superior relative radiobiological effectiveness (RBE). The Monte Carlo Geant4 toolkit is used to simulate the complete CNAO extraction beamline, with the active and passive components along it. A human eye modeled detector, including a realistic target tumor volume, is used as target. Cross check with previous studies at CNAO using protons allows comparisons on possible benefits on using such a technique with respect to proton beams. Before the eye-detector irradiation a validation of the Geant4 simulation with CNAO experimental data is carried out with both carbon ions and protons. Important beam parameters such as the transverse FWHM and scanned radiation field 's uniformity are tested within the simulation and compared with experimental measurements at CNAO Centre. The physical processes involved in secondary particles generation by carbon ions and protons in the eye-detector are reproduced to take into account the additional dose to the primary beam given to irradiated eye's tissues. A study of beam shaping is carried out to produce a uniform 3D dose distribution (shaped on the tumor) by the use of a spread out Bragg peak. The eye-detector is then irradiated through a two dimensional transverse beam scan at different depths. In the use case the eye-detector is rotated of an angle of 40 deg. in the vertical direction, in order to mis-align the tumor from healthy tissues in front of it. The treatment uniformity on the tumor in the eye-detector is tested. For a more quantitative description of the deposited dose in the eye-detector and for the evaluation of the ratio between the dose deposited in the tumor and

Treatment planning, optimization, and beam delivery technqiues for intensity modulated proton therapy

Science.gov (United States)

Sengbusch, Evan R.

Physical properties of proton interactions in matter give them a theoretical advantage over photons in radiation therapy for cancer treatment, but they are seldom used relative to photons. The primary barriers to wider acceptance of proton therapy are the technical feasibility, size, and price of proton therapy systems. Several aspects of the proton therapy landscape are investigated, and new techniques for treatment planning, optimization, and beam delivery are presented. The results of these investigations suggest a means by which proton therapy can be delivered more efficiently, effectively, and to a much larger proportion of eligible patients. An analysis of the existing proton therapy market was performed. Personal interviews with over 30 radiation oncology leaders were conducted with regard to the current and future use of proton therapy. In addition, global proton therapy market projections are presented. The results of these investigations serve as motivation and guidance for the subsequent development of treatment system designs and treatment planning, optimization, and beam delivery methods. A major factor impacting the size and cost of proton treatment systems is the maximum energy of the accelerator. Historically, 250 MeV has been the accepted value, but there is minimal quantitative evidence in the literature that supports this standard. A retrospective study of 100 patients is presented that quantifies the maximum proton kinetic energy requirements for cancer treatment, and the impact of those results with regard to treatment system size, cost, and neutron production is discussed. This study is subsequently expanded to include 100 cranial stereotactic radiosurgery (SRS) patients, and the results are discussed in the context of a proposed dedicated proton SRS treatment system. Finally, novel proton therapy optimization and delivery techniques are presented. Algorithms are developed that optimize treatment plans over beam angle, spot size, spot spacing

Ion beam surface treatment: A new capability for rapid melt and resolidification of surfaces

International Nuclear Information System (INIS)

Stinnett, R.W.; McIntyre, D.C.; Buchheit, R.G.; Greenly, J.B.; Thompson, M.O.

1994-01-01

The emerging capability to produce high average power (5--250 kW) pulsed ion beams at 0.2--2 MeV energies is enabling us to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This technique uses high energy, pulsed (≤100 ns) ion beams to directly deposit energy in the top 2--20 micrometers of the surface of any material. Depth of treatment is controllable by varying the ion energy and species. Deposition of the energy with short pulses in a thin surface layer allows melting of the layer with relatively small energies and allows rapid cooling of the melted layer by thermal diffusion into the underlying substrate. Typical cooling rates of this process (10 9 10 10 K/sec) cause rapid resolidification, resulting in production of non-equilibrium microstructures (nano-crystalline and metastable phases) that have significantly improved corrosion, wear, and hardness properties. We have conducted IBEST feasibility experiments with results confirming surface hardening, nanocrystaline grain formation, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning

Simple beam profile monitor

Energy Technology Data Exchange (ETDEWEB)

Gelbart, W.; Johnson, R. R.; Abeysekera, B. [ASD Inc. Garden Bay, BC (Canada); Best Theratronics Ltd Ottawa Ontario (Canada); PharmaSpect Ltd., Burnaby BC (Canada)

2012-12-19

An inexpensive beam profile monitor is based on the well proven rotating wire method. The monitor can display beam position and shape in real time for particle beams of most energies and beam currents up to 200{mu}A. Beam shape, position cross-section and other parameters are displayed on a computer screen.

Effects of beam, target and substrate potentials in ion beam processing

International Nuclear Information System (INIS)

Harper, J.M.E.

1982-01-01

Ion beam etching and deposition are normally carried out with beam, target and substrate potentials near ground potential. In this paper, the effects of intentional or unintentional changes in these potentials are described. Examples include beam neutralization, a single extraction grid, substrate bias, and target bias. Each example is described in terms of beam plasma parameters. (Auth.)

Beam profile monitors for a tagged photon beam facility

International Nuclear Information System (INIS)

Arends, J.; Breuer, M.; Dahmen, H.D.; Detemple, P.; Schneider, W.; Urban, D.; Zucht, B.

1991-01-01

A beam profile monitor for electron and photon beams is described, which operates at the low intensities encountered in a tagged bremsstrahlung beam environment, typically 10 10 electrons/s and 10 7 photons/s. The method is based on a wire scanner and utilizes the presence of a tagging spectrometer. The accuracy of the measurements can be tuned in a wide range to meet the requirements set by the actual beam parameters. Examples of measured electron and photon beam profiles at the tagged photon beam of the PHOENICS experiment at the electron stretcher ring ELSA in Bonn are given. (orig.)

Limitations due to strong head-on beam-beam interactions (MD 1434)

CERN Document Server

Buffat, Xavier; Iadarola, Giovanni; Papadopoulou, Parthena Stefania; Papaphilippou, Yannis; Pellegrini, Dario; Pojer, Mirko; Crockford, Guy; Salvachua Ferrando, Belen Maria; Trad, Georges; Barranco Garcia, Javier; Pieloni, Tatiana; Tambasco, Claudia; CERN. Geneva. ATS Department

2017-01-01

The results of an experiment aiming at probing the limitations due to strong head on beam-beam interactions are reported. It is shown that the loss rates significantly increase when moving the working point up and down the diagonal, possibly due to effects of the 10th and/or 14th order resonances. Those limitations are tighter for bunches with larger beam-beam parameters, a maximum total beam-beam tune shift just below 0.02 could be reached.

Association of rectal toxicity with thermal dose parameters in treatment of locally advanced prostate cancer with radiation and hyperthermia

International Nuclear Information System (INIS)

Hurwitz, Mark D.; Kaplan, Irving D.; Hansen, Jorgen L.; Prokopios-Davos, Savina; Topulos, George P.; Wishnow, Kenneth; Manola, Judith; Bornstein, Bruce A.; Hynynen, Kullervo

2002-01-01

Purpose: Although hyperthermia has been used for more than two decades in the treatment of pelvic tumors, little is known about the potential impact of heat on rectal toxicity when combined with other treatment modalities. Because rectal toxicity is a concern with radiation and may be exacerbated by hyperthermia, definition of the association of thermal dose parameters with rectal toxicity is important. In this report, we correlate rectal toxicity with thermal dose parameters for patients treated with hyperthermia and radiation for prostate cancer. Methods and Materials: Thirty patients with T2b-T3b disease (1992 American Joint Committee On Cancer criteria) enrolled in a Phase II study of external beam radiation ± androgen-suppressive therapy with two transrectal ultrasound hyperthermia treatments were assessed for rectal toxicity. Prostatic and anterior rectal wall temperatures were monitored for all treatments. Rectal wall temperatures were limited to 40 deg. C in 19 patients, 41 deg. C in 3 patients, and 42 deg. C in 8 patients. Logistic regression was used to estimate the log hazard of developing National Cancer Institute Common Toxicity Criteria Grade 2 toxicity based on temperature parameters. The following were calculated: hazard ratios, 95% confidence intervals, p values for statistical significance of each parameter, and proportion of variability explained for each parameter. Results: Gastrointestinal toxicity was limited to Grade 2. The rate of acute Grade 2 proctitis was greater for patients with an allowable rectal wall temperature of >40 deg. C. In this group, 7 of 11 patients experienced acute Grade 2 proctitis, as opposed to 3 of 19 patients in the group with rectal wall temperatures limited to 40 deg. C (p=0.004). Preliminary assessment of long-term toxicity revealed no differences in toxicity. Hazard ratios for acute Grade 2 proctitis for allowable rectal wall temperature, average rectal wall Tmax, and average prostate Tmax were 9.33 (p=0.01), 3

Influence of two-stream relativistic electron beam parameters on the space-charge wave with broad frequency spectrum formation

Science.gov (United States)

Alexander, LYSENKO; Iurii, VOLK

2018-03-01

We developed a cubic non-linear theory describing the dynamics of the multiharmonic space-charge wave (SCW), with harmonics frequencies smaller than the two-stream instability critical frequency, with different relativistic electron beam (REB) parameters. The self-consistent differential equation system for multiharmonic SCW harmonic amplitudes was elaborated in a cubic non-linear approximation. This system considers plural three-wave parametric resonant interactions between wave harmonics and the two-stream instability effect. Different REB parameters such as the input angle with respect to focusing magnetic field, the average relativistic factor value, difference of partial relativistic factors, and plasma frequency of partial beams were investigated regarding their influence on the frequency spectrum width and multiharmonic SCW saturation levels. We suggested ways in which the multiharmonic SCW frequency spectrum widths could be increased in order to use them in multiharmonic two-stream superheterodyne free-electron lasers, with the main purpose of forming a powerful multiharmonic electromagnetic wave.

Electron beam treatment plant for textile dyeing wastewater

International Nuclear Information System (INIS)

Han, B.; Kim, J.; Kim, Y.; Choi, J.; Ahn, S.; Makarov, I.E.; Ponomarev, A.V.

2006-01-01

A pilot plant for treating 1,000 m 3 of textile dyeing wastewater per day with electron beam has constructed and operated continuously in Daegu, Korea since 1998. This plant is combined with biological treatment system and it shows the reduction of chemical reagent consumption, and also the reduction in retention time with the increase in removal efficiencies of COD Cr and BOD 5 up to 30∼40%. Increase in biodegradability after radiation treatment of aqueous-organic systems is due to radiolytical conversions of non-biodegradable compounds. On the basis of data obtained from pilot plant operation, construction of actual industrial scale plant has started in 2003, and will be finished by 2005. This plant is located on the area of existing wastewater treatment facility (Daegu Dyeing Industrial Complex) and to have treatment capacity 10,000 m 3 of wastewater per day using one 1 MeV, 400 kW accelerator, and combined with existing bio- treatment facility. The overall construction cost and the operation cost in the radiation processing, when compared to other conventional and advanced oxidation techniques, are more cost-effective and convenient for wastewater treatment. This project is supported by the International Atomic Energy Agency (IAEA) and Korean Government. (author)

Investigation of the flip-flop beam-beam effect in SPEAR

International Nuclear Information System (INIS)

Donald, M.H.R.; Paterson, J.M.

1980-01-01

When colliding electron and positron bunches in SPEAR at high values of the beam-beam tune shift parameter Δν, it had been observed that sometimes one of the equal intensity beams would blow up in the vertical plane more than the other beam. It was subsequently found that a small adjustment to the phase difference between the RF accelerating cavities would make the beam flip the other way. The results of the investigation of this phenomenon are presented in this paper

Investigation of the flip-flop beam--beam effect in SPEAR

International Nuclear Information System (INIS)

Donald, M.H.R.; Paterson, J.M.

1979-03-01

When colliding electron and positron bunches in SPEAR at high values of the beam--beam tune shift parameter Δν, it had been observed that sometimes one of the equal intensity beams would blow up in the vertical plane more than the other beam. It was subsequently found that a small adjustment to the phase difference between the RF accelerating cavities would make the beam flip the other way. The results of the investigation of this phenomenon are presented in this paper

Treatment simulation approaches for the estimation of the distributions of treatment quality parameters generated by geometrical uncertainties

International Nuclear Information System (INIS)

Baum, C; Alber, M; Birkner, M; Nuesslin, F

2004-01-01

Geometric uncertainties arise during treatment planning and treatment and mean that dose-dependent parameters such as EUD are random variables with a patient specific probability distribution. Treatment planning with highly conformal treatment techniques such as intensity modulated radiation therapy requires new evaluation tools which allow us to estimate this influence of geometrical uncertainties on the probable treatment dose for a planned dose distribution. Monte Carlo simulations of treatment courses with recalculation of the dose according to the daily geometric errors are a gold standard for such an evaluation. Distribution histograms which show the relative frequency of a treatment quality parameter in the treatment simulations can be used to evaluate the potential risks and chances of a planned dose distribution. As treatment simulations with dose recalculation are very time consuming for sufficient statistical accuracy, it is proposed to do treatment simulations in the dose parameter space where the result is mainly determined by the systematic and random component of the geometrical uncertainties. Comparison of the parameter space simulation method with the gold standard for prostate cases and a head and neck case shows good agreement as long as the number of fractions is high enough and the influence of tissue inhomogeneities and surface curvature on the dose is small

Industrial Products for Beam Instrumentation

CERN Document Server

Schmickler, Hermann

2001-01-01

In various branches of high technology industry there has been considerable progress in the past years which could be used for beam instrumentation. The subject will be introduced by two short demonstrations: a demonstration of modern audio electronics with 24bit-96kHz ADC, digital signal electronics and application programs under windows on a PC, which allow to change the parameters of the signal treatment. Potential applications are data monitoring at constant sampling frequency, orbit feedbacks (including high power audio amplifiers), noise reduction on beam current transformers... digital treatment of video signals webcams, frame grabbers, CCD-data via USB, all one needs for image acquisitions, in particular interesting for profile measurements. These introductory demonstrations will not last longer than 30 minutes. The remaining time will be used to pass through the audience collecting information into a two dimensional table, which shall contain as row index the accelerator and as column index the t...

The Lhc beam commissioning

International Nuclear Information System (INIS)

Redarelli, S.; Bailey, R.

2008-01-01

The plans for the Lhc proton beam commissioning are presented. A staged commissioning approach is proposed to satisfy the request of the Lhc experiments while minimizing the machine complexity in early commissioning phases. Machine protection and collimation aspects will be tackled progressively as the performance will be pushed to higher beam intensities. The key parameters are the number of bunches, k b , the proton intensity pe bunch, N, and the β in the various interaction points. All together these parameters determine the total beam power and the complexity of the machine. We will present the proposed trade off between the evolution of these parameters and the Lhc luminosity performance.

Neutrino parameters with magical beta-beam at INO

Energy Technology Data Exchange (ETDEWEB)

Agarwalla, Sanjib Kumar; Choubey, Sandhya; Raychaudhuri, Amitava [Harish-Chandra Research Institute, Allahabad (India)], E-mail: sanjib@hri.res.in

2008-11-01

We have studied the physics reach of an experiment where neutrinos produced in a beta-beam facility at CERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The idea of beta-beam is based on the production of a pure, intense, collimated beam of electron neutrinos or their antiparticles via the beta decay of accelerated radioactive ions circulating in a storage ring. Interestingly, the CERN-INO distance of 7152 km happens to be tantalizingly close to the so-called 'magic' baseline where the sensitivity to the neutrino mass ordering (sign of {delta}m{sup 2}{sub 31} {identical_to} m{sup 2}{sub 3} - m{sup 2}{sub 1}) and more importantly, {theta}{sub 13}, goes up significantly, while the sensitivity to the unknown CP phase is absent. This permits such an experiment involving the golden P{sub e{mu}} channel to make precise measurements of the mixing angle {theta}{sub 13} and neutrino mass hierarchy avoiding the issues of intrinsic degeneracies and correlations which plague other baselines.

Efficacy of flattening-filter-free beam in stereotactic body radiation therapy planning and treatment: A systematic review with meta-analysis

International Nuclear Information System (INIS)

Dang, Thu M.; Peters, Mitchell J.; Hickey, Brigid; Semciw, Adam

2017-01-01

A linear accelerator with the flattening-filter removed generates a non-uniform dose profile beam. We aimed to analyse and compare plan quality and treatment time between flattened beam (FB) and flattening-filter-free (FFF) beam to assess the efficacy of FFF beam for stereotactic body radiation therapy (SBRT). The search strategy was based around 3 concepts; radiation therapy, flattening-filter-free and treatment delivery. The years searched were restricted from 2010 to date of review (October 2015). All plan quality comparisons were between FFF and FB plans from the same data sets. We identified 210 potential studies based on the three searched concepts. All articles were screened by two authors for title and abstract and by three authors for full text. Ten studies met the eligibility criteria. Plan quality was evaluated using conformity index (CI), heterogeneity index (HI) and gradient index (GI). Dose to organs-at-risk (OAR) and healthy tissues were compared. Differences between beam-on-time (BOT) and treatment time (T × T) were also analysed. Normalized percentage ratios of CI and HI demonstrated no clinical differences among the studied articles. GI displayed small variations between the articles favouring FFF beam. The BOT with FFF is substantially reduced, and appears to impact the frequency of intra-fraction imaging which, in turn, affects total treatment time. Based on planning tumour volume (PTV) coverage, dose to OAR and healthy tissue sparing, FFF beam is clinically effective for the treatment of cancer patients using SBRT. We recommend the use of FFF beam for SBRT based on these factors and the reported overall treatment time reduction.

Transverse equilibria in linear collider beam-beam collisions

International Nuclear Information System (INIS)

Rosenzweig, J.B.; Chen, Pisin

1991-01-01

It has been observed in simulations of the beam-beam interaction in linear colliders that a near equilibrium pinched state of the colliding beams develops when the disruption parameter is large (D much-gt 1). In this state the beam transverse density distributions are peaked at center, with long tails. The authors present here an analytical model of the equilibrium approached by the beams, that of a generalized Bennett pinch which develops through collisionless damping due to the strong nonlinearity of the beam-beam interaction. In order to calculate the equilibrium pinched beam size, an estimation of the rms emittance growth is made which takes into account the partial adiabaticity of the collision. This pinched beam size is used to derive the luminosity enhancement factors whose scaling is in agreement with the simulation results for both D and thermal factor A = σ z /β * large, and explains the previously noted cubic relationship between round and flat beam enhancement factors

Research on electron beam welding technology of steel HR-4

International Nuclear Information System (INIS)

Guo Peng; Guan Kai

2001-01-01

The electron beam weldability of HR- 4 steels (J75 and J90) is studied and the welding parameters needed for design and usage are presented. The assessment on the effect of mechanical properties by different processing order of welding and heat-treatment is made

Preliminary study of e-beam processing as a phytosanitary treatment against Guignardia citricarpa

International Nuclear Information System (INIS)

Araujo, Michel M.; Fanaro, Gustavo B.; Silveira, Ana P.M.; Rogovschi, Vladimir D.; Villavicencio, Anna L.C.H.; Correa, Benedito

2009-01-01

Citrus black spot (CBS) is a fungal disease, caused by Guignardia citricarpa and affects practically all citrus species of economic importance, especially sweet oranges. It has become a serious, widespread problem for citrus production in South America. It causes lesions on citrus fruit peel and leaves and can induce fruit drop before maturity. Fruits from citrus areas affected by CBS represent a risk for introduction of this pathogen into new areas. European Community and United States severely limit importation of fresh citrus fruit from those countries were the disease is present. Various treatments have been explored to reduce the risk of introduction of CBS into countries that are currently free of this disease. E-beam processing has been successfully used to inactivate food spoilage microorganisms, including bacteria, yeasts and moulds. Ionizing radiation treatment has been known to extend the postharvest life of many tropical and subtropical fruits. Irradiation is the most recent commercial phytosanitary treatment for fresh commodities. The aim of this study was to assess the effect of electron beam processing on the viability of G. citricarpa. Isolated fungi from naturally infected oranges were irradiated with 2.5, 5.0, 7.5, 10.0 and 12.5 kGy using an electron beam irradiator (Radiation Dynamics Co., model JOB-188, New York, USA). Irradiation appeared to be a useful alternative as a phytosanitary treatment to control citrus black spot dissemination. (author)

Optimization of beam parameters of electron gun for 2.5 MeV/100 kW high power industrial accelerator

International Nuclear Information System (INIS)

Pramod, R.; Petwal, V.C.

2009-01-01

A 2.5 MeV/100 kW transformer type industrial accelerator is being developed at RRCAT. A Pierce type electron gun consisting of 10 mm diameter LaB 6 disc (indirectly heated) is used as a source of electron beam. The cathode assembly is put on the top of the accelerating structure, which consists of many electrostatic lenses of which the first lens acts as anode of the gun. The quality of the beam injected into the accelerating structure depends on the anode voltage, shape and size of anode and its distance from the cathode. The anode is subjected to variable voltage during the operation of accelerator from energy 1 MeV to 2.5 MeV, which results in variable emittance at the exit of the electron gun. The electron beam from the gun should provide parallel or slightly convergent beam with long focal length and the emittance of the beam at the exit of electron gun should match the beam acceptance limit of the accelerating structure. The EGUN code is used to optimize the shape and size of the anode, its distance from the cathode to achieve above objectives. Our study suggests that the desired beam parameters at the exit of the anode can be obtained by reducing the aperture size of the anode and by applying suitable voltage gradient to the anode. (author)

Symmetrization of the beam-beam interaction in an asymmetric collider

International Nuclear Information System (INIS)

Chin, Y.H.

1990-07-01

This paper studies the idea of symmetrizing both the lattice and the beams of an asymmetric collider, and discusses why this regime should be within the parametric reach of the design in order to credibly ensure its performance. Also examined is the effectiveness of a simple compensation method using the emittance as a free parameter and that it does not work in all cases. At present, when there are no existing asymmetric colliders, it seems prudent to design an asymmetric collider so as to be similar to a symmetric one (without relying on a particular theory of the asymmetric beam-beam interaction that has not passed tests of fidelity). Nevertheless, one must allow for the maximum possible flexibility and freedom in adjusting those parameters that affect luminosity. Such a parameter flexibility will be essential in tuning the collider to the highest luminosity

The effect of electron beam parameters on the yield of gel fraction of some varnish systems

International Nuclear Information System (INIS)

Achmatowicz, T.; Jozwiak, H.; Zielinska, T.

1979-01-01

Results of studies carried out using a straight electron beam from accelerators LAE 13/9 and Elit-1 are presented. Using a variable dose rate, controlled by the distance from the accelerator window, pulse current, pulse duration and pulse repetition rate in LAE 13/9 the yield of the gel fraction of some varnishes and resins at a given dose has been determined. Using Elit-1 the dependence of the gel fraction content on the dose for pulses of various repetition rate has been examined. It has been shown that the dose rate and other beam parameters affect the course of the curing process of the examined compositions. The curing conditions established in LAE 13/9 can be a basis for processes carried out on a commercial scale. (author)

Residual stress reduction in beam welded joints by means of stress redistribution using defocused electron or laser beams; Eigenspannungsreduktion in strahlgeschweissten Naehten mittels Spannungsumlagerung durch den Einsatz defokussierter Elektronen- bzw. Laserstrahlen

Energy Technology Data Exchange (ETDEWEB)

Toelle, Florian

2013-08-01

Among the multiple advantages of beam welding processes the high longitudinal residual stresses in beam welds ranging till the local yield stress are one disadvantage. These high stresses can influence the service life of the welded components. The residual stresses in other welding processes exist in an equal high level but primarily in the transverse direction to the weld. To mitigate the high residual stresses a couple of methods were developed for these welding processes in the last decades. However these methods need large contact surfaces next to the welds for the installation of matched heating and cooling elements and other additional equipment. Furthermore, the previous developed stress mitigating processes offer a low efficiency for the small beam welds. The stress reduction by using the welding source after the welding process for a remote heat treatment of the welded components afford a flexible tool for the stress mitigation in beam welds. This method does not need any additional equipment and it is applicable for complex welding and component geometries. During this post welding heat treatment the material next to the weld is heated by the defocused electron or by the defocused laser beam, respectively, to temperatures of some hundreds degree Celsius. Hereby low plastic deformations in these regions are generated. While cooling down due to the thermal shrinkage the material between the weld and the heat treated region is compressed in longitudinal direction to the weld. This intermediate material zone constrained the shrinkage of the weld while cooling down from the melting temperature and leads to the high longitudinal residual stresses in the weld. In consequence of the compression of this intermediate zones by the heat treated zones the resistance to the shrinkage of the weld is lowered and the longitudinal stresses in the weld are reduced. In the process the quantity of the stress reduction is controlled by the selection of the process parameters

Treatment planning considerations in contrast-enhanced radiotherapy: energy and beam aperture optimization

Energy Technology Data Exchange (ETDEWEB)

Garnica-Garza, H M, E-mail: hgarnica@cinvestav.mx [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional Unidad Monterrey, Via del Conocimiento 201 Parque de Investigacion e Innovacion Tecnologica, Apodaca NL CP 66600 (Mexico)

2011-01-21

It has been shown that the use of kilovoltage x-rays in conjunction with a contrast agent incorporated into the tumor can lead to acceptable treatment plans with regard to the absorbed dose distribution produced in the target as well as in the tissue and organs at risk surrounding it. In this work, several key aspects related to the technology and irradiation techniques necessary to clinically implement this treatment modality are addressed by means of Monte Carlo simulation. The Zubal phantom was used to model a prostate radiotherapy treatment, a challenging site due to the depth of the prostate and the presence of bony structures that must be traversed by the x-ray beam on its way to the target. It is assumed that the concentration levels of the enhancing agent present in the tumor are at or below 10 mg per 1 g of tissue. The Monte Carlo code PENELOPE was used to model a commercial x-ray tube having a tungsten target. X-ray energy spectra for several combinations of peak electron energy and added filtration were obtained. For each energy spectrum, a treatment plan was calculated, with the PENELOPE Monte Carlo code, by modeling the irradiation of the patient as 72 independent conformal beams distributed at intervals of 5{sup 0} around the phantom in order to model a full x-ray source rotation. The Cimmino optimization algorithm was then used to find the optimum beam weight and energy for different treatment strategies. It is shown that for a target dose prescription of 72 Gy covering the whole tumor, the maximum rectal wall and bladder doses are kept below 52 Gy for the largest concentration of contrast agent of 10 mg per 1 g of tissue. It is also shown that concentrations of as little as 5 mg per 1 g of tissue also render dose distributions with excellent sparing of the organs at risk. A treatment strategy to address the presence of non-uniform distributions of the contrast agent in the target is also modeled and discussed.

Fiber coupled diode laser beam parameter product calculation and rules for optimized design

Science.gov (United States)

Wang, Zuolan; Segref, Armin; Koenning, Tobias; Pandey, Rajiv

2011-03-01

The Beam Parameter Product (BPP) of a passive, lossless system is a constant and cannot be improved upon but the beams may be reshaped for enhanced coupling performance. The function of the optical designer of fiber coupled diode lasers is to preserve the brightness of the diode sources while maximizing the coupling efficiency. In coupling diode laser power into fiber output, the symmetrical geometry of the fiber core makes it highly desirable to have symmetrical BPPs at the fiber input surface, but this is not always practical. It is therefore desirable to be able to know the 'diagonal' (fiber) BPP, using the BPPs of the fast and slow axes, before detailed design and simulation processes. A commonly used expression for this purpose, i.e. the square root of the sum of the squares of the BPPs in the fast and slow axes, has been found to consistently under-predict the fiber BPP (i.e. better beam quality is predicted than is actually achievable in practice). In this paper, using a simplified model, we provide the proof of the proper calculation of the diagonal (i.e. the fiber) BPP using BPPs of the fast and slow axes as input. Using the same simplified model, we also offer the proof that the fiber BPP can be shown to have a minimum (optimal) value for given diode BPPs and this optimized condition can be obtained before any detailed design and simulation are carried out. Measured and simulated data confirms satisfactory correlation between the BPPs of the diode and the predicted fiber BPP.

Impact of beam-beam effects on precision luminosity measurements at the ILC

Energy Technology Data Exchange (ETDEWEB)

Rimbault, C [LAL, Univ Paris-Sud, IN2P3/CNRS, Orsay (France); Bambade, P [LAL, Univ Paris-Sud, IN2P3/CNRS, Orsay (France); Moenig, K [DESY, Zeuthen (Germany); Schulte, D [CERN, Geneva (Switzerland)

2007-09-15

In this paper, the impact of beam-beam effects on the precision luminosity measurement at the International Linear Collider is investigated quantitatively for the first time. GUINEA-PIG, a beam-beam interaction simulation tool, is adapted to treat the space charge effects affecting the Bhabha events used in this measurement. The biases due to the resulting changes in kinematics are evaluated for different center-of-mass energies and beam parameters.

Impact of beam-beam effects on precision luminosity measurements at the ILC

CERN Document Server

Rimbault, C; Mönig, K; Schulte, D

2007-01-01

In this paper, the impact of beam-beam effects on the precision luminosity measurement at the International Linear Collider is investigated quantitatively for the first time. GUINEA-PIG, a beam-beam interaction simulation tool, is adapted to treat the space charge effects affecting the Bhabha events used in this measurement. The biases due to the resulting changes in kinematics are evaluated for different center-of-mass energies and beam parameters.

Applied dosimetry to ionization techniques by electron beams

International Nuclear Information System (INIS)

Kuntz, F.

1991-12-01

After a general introduction about electron beam dosimetry, the second part is about the determination of treatment parameter for an electron ionization: are treated the problems of electron path determination, treatment depth of a product and finally, the radiation dose heterogeneities in all the volume of a treated product. The third part describes a process that greatly reduces radiation dose heterogeneity and then industrial interest is analyzed. The fourth part describes 2 applications of diffusion screen utilization. 66 figs

Orbital parameters of proton and deuteron beams in the NICA collider with solenoid Siberian snakes

International Nuclear Information System (INIS)

Kovalenko, A D; Butenko, A V; Kekelidze, V D; Mikhaylov, V A; Kondratenko, M A; Filatov, Yu N; Kondratenko, A M

2016-01-01

Two solenoid Siberian snakes are required to obtain ion polarization in the “spin transparency” mode of the NICA collider. The field integrals of the solenoid snakes for protons and deuterons at maximum momentum of 13.5 GeV/c are equal to 2×50 T·m and 2×160 T·m respectively. The snakes introduce strong betatron oscillation coupling. The calculations of orbital parameters of proton and deuteron beams in NICA collider with solenoid snakes are presented. (paper)

Focusing and bunching of ion beam in axial injection channel of IPHC cyclotron TR24

Science.gov (United States)

Adam, T.; Ivanenko, I.; Kazarinov, N.; Osswald, F.; Traykov, E.

2017-07-01

The CYRCe cyclotron (CYclotron pour la ReCherche et l’Enseignement) is used at IPHC (Institut Pluridisciplinaire Hubert Curien) for the production of radio-isotopes for diagnostics, medical treatments and fundamental research in radiobiology. The TR24 cyclotron produced and commercialized by ACSI (Canada) delivers a 16-25 MeV proton beam with intensity from few nA up to 500 μA. The solenoidal focusing instead of existing quadrupole one is proposed in this report. The changing of the focusing elements will give the better beam matching with the acceptance of the spiral inflector of the cyclotron. The parameters of the focusing solenoid are found. Additionally, the main parameters of the bunching system are evaluated in the presence of the beam space charge. This system consists of the buncher installed in the axial injection beam line of the cyclotron. The using of the grid-less multi harmonic buncher may increase the accelerated beam current and will give the opportunity to new proton beam applications.

SU-E-E-01: Commissiong of Linear Accelerator and Beam Modeling in Treatment Planning Systems.

Science.gov (United States)

Pella, S; Chilukuri, M; Smith, C; Bacala, A; Dumitru, N

2012-06-01

Sooner or later every medical physicist is involved with commissioning and beam modeling of a new linear accelerator (linac) and a new treatment planning system (TPS). In spite of all instructions and training offered by the vendors, at the time a new linac is being purchased and added to the present ones the outside help is not so complete. The physicist who has to perform the commissioning job may not even be the one who was trained for that. What we are missing is a good comprehensive set of information and instructions on how to do's. From shielding calculation verifications, surveys, to collecting the beam data, modeling, entering the data into the TPS, and verifications of the goodness of the data we need a lot of support and we don't have it. I will provide a step by step description of the required work with the results we are looking for. Presentation of the shielding calculations, survey required, tools needed to perform them. Detailed beam data collections, scanning system needed, machine set of specs needed, applicator details needed. Importing beam data from the scanning system and beam calculations. Algorithms used in dose calculation, IMRT optimization, heterogeneity corrections presented to be understood before modeling the beam data. At the completion of this course the medical physicist will be able to commission a linear accelerator and a treatment planning system with confidence and very little help from the outside. This compendium of detailed instructions on commissioning a linear accelerator will provide good uidance to every physicist who will be involved with the installation and bringing into safe use for treatment of a new linear accelerator. © 2012 American Association of Physicists in Medicine.

SU-D-BRC-01: An Automatic Beam Model Commissioning Method for Monte Carlo Simulations in Pencil-Beam Scanning Proton Therapy

Energy Technology Data Exchange (ETDEWEB)

Qin, N; Shen, C; Tian, Z; Jiang, S; Jia, X [UT Southwestern Medical Ctr, Dallas, TX (United States)

2016-06-15

Purpose: Monte Carlo (MC) simulation is typically regarded as the most accurate dose calculation method for proton therapy. Yet for real clinical cases, the overall accuracy also depends on that of the MC beam model. Commissioning a beam model to faithfully represent a real beam requires finely tuning a set of model parameters, which could be tedious given the large number of pencil beams to commmission. This abstract reports an automatic beam-model commissioning method for pencil-beam scanning proton therapy via an optimization approach. Methods: We modeled a real pencil beam with energy and spatial spread following Gaussian distributions. Mean energy, and energy and spatial spread are model parameters. To commission against a real beam, we first performed MC simulations to calculate dose distributions of a set of ideal (monoenergetic, zero-size) pencil beams. Dose distribution for a real pencil beam is hence linear superposition of doses for those ideal pencil beams with weights in the Gaussian form. We formulated the commissioning task as an optimization problem, such that the calculated central axis depth dose and lateral profiles at several depths match corresponding measurements. An iterative algorithm combining conjugate gradient method and parameter fitting was employed to solve the optimization problem. We validated our method in simulation studies. Results: We calculated dose distributions for three real pencil beams with nominal energies 83, 147 and 199 MeV using realistic beam parameters. These data were regarded as measurements and used for commission. After commissioning, average difference in energy and beam spread between determined values and ground truth were 4.6% and 0.2%. With the commissioned model, we recomputed dose. Mean dose differences from measurements were 0.64%, 0.20% and 0.25%. Conclusion: The developed automatic MC beam-model commissioning method for pencil-beam scanning proton therapy can determine beam model parameters with

Longitudinal impedance of a step-in for a round beam at arbitrary beam energy

Energy Technology Data Exchange (ETDEWEB)

Al-Khateeb, A.M., E-mail: a.alkhateeb@gsi.d [FAIR-Accelerator Theory Group, GSI Darmstadt, Planckstr. 1, D-64291 Darmstadt (Germany); Boine-Frankenheim, O.; Plotnikov, A. [FAIR-Accelerator Theory Group, GSI Darmstadt, Planckstr. 1, D-64291 Darmstadt (Germany); Shim, S.Y. [FAIR Division, Magnettechnik/Kryotechnik, GSI Darmstadt, Planckstr. 1, D-64291 Darmstadt (Germany); Haenichen, L. [Technische Universitaet Darmstadt, Institut fuer Theorie elektromagnetischer Felder, TEMF, Schlossgartenstr. 8, D-64289 Darmstadt (Germany)

2011-01-21

Contribution of step-in geometric discontinuity to the longitudinal coupling impedance has been obtained analytically using exact field matching. We assumed a perfectly conducting beam-pipe wall of two different radii connected coaxially at z=0 so that the contribution to the longitudinal coupling impedance is purely due to the beam-pipe geometric discontinuity. We also obtained the longitudinal loss factor for a Gaussian beam as a function of beam energy and bunch length. Results have been analyzed numerically for some representative parameters close to real machine parameters. Analytical results have also been compared with numerical simulation from CST at relativistic beam energies. We found a very good agreement between theory and simulation.

Title: a simple method to evaluate linac beam homogeneity

International Nuclear Information System (INIS)

Monti, A.F.; Ostinelli, A.; Gelosa, S.; Frigerio, M.

1995-01-01

Quality Control (QC) tests in Radiotherapy represent a basic requirement to asses treatment units performance and treatment quality. Since they are generally time consuming, it is worth while to introduce procedures and methods which can be carried on more easily and quickly. Since 1994 in the Radiotherapy Department of S. Anna Hospital, it had been employed a commercially available solid phantom (PRECITRON) with a 10 diodes array, to investigate beam homogeneity (symmetry and flatness). In particular, global symmetry percentage indexes were defined which consider pairs of corresponding points along each axis (x and y) and compare the readings of the respective diodes, following the formula: (I gs =((X d + X -d ) - (Y d + Y -d )((X d + X -d ) + (Y d + Y -d )*200 where X d and X -d are points 8 or 10 cm equally spaced from the beam centre along x axis and the same for Y d and Y -d along y axis. Even if non supporting international protocols requirements as a whole, this parameter gives an important information about beam homogeneity, when only few points of measure are available in a plane, and it can be daily determined, thus fulfilling the aim of lightning immediately each situation capable to compromise treatment accuracy and effectiveness. In this poster we report the results concerning this parameter for a linear accelerator (Varian Clinac 1800), since September 1994 to September 1995

Online Structural Health Monitoring and Parameter Estimation for Vibrating Active Cantilever Beams Using Low-Priced Microcontrollers

Directory of Open Access Journals (Sweden)

Gergely Takács

2015-01-01

Full Text Available This paper presents a structural health monitoring and parameter estimation system for vibrating active cantilever beams using low-cost embedded computing hardware. The actuator input and the measured position are used in an augmented nonlinear model to observe the dynamic states and parameters of the beam by the continuous-discrete extended Kalman filter (EKF. The presence of undesirable structural change is detected by variations of the first resonance estimate computed from the observed equivalent mass, stiffness, damping, and voltage-force conversion coefficients. A fault signal is generated upon its departure from a predetermined nominal tolerance band. The algorithm is implemented using automatically generated and deployed machine code on an electronics prototyping platform, featuring an economically feasible 8-bit microcontroller unit (MCU. The validation experiments demonstrate the viability of the proposed system to detect sudden or gradual mechanical changes in real-time, while the functionality on low-cost miniaturized hardware suggests a strong potential for mass-production and structural integration. The modest computing power of the microcontroller and automated code generation designates the proposed system only for very flexible structures, with a first dominant resonant frequency under 4 Hz; however, a code-optimized version certainly allows much stiffer structures or more complicated models on the same hardware.

Behaviour of some fresh fruits under electron-beam irradiation

International Nuclear Information System (INIS)

Ferdes, O.; Stroia, A.L.; Potcoava, A.; Cojocaru, M.; Mihnea, R.; Oproiu, C.

1994-01-01

The use of ionizing radiation in preservation of fruits and vegetables is widely recognized. In this paper it is presented a study of the effect of electron-beam irradiation of some fresh, early and perishable fruits, like strawberries, cherries, and sour cherries concerning their shelf-life time extension. The irradiations were performed on common varieties in normal conditions to the IPTRD's electron-beam accelerator (Bucharest-Magurele) having the following parameters: flow current 10 μA, power 60 W and electron mean energy 6.23 MeV. The irradiation doses varied between 0.5-3.0 kGy and the dose rates between 100-1500 Gy/min. It was observed the fruit preservation capability of the treatment and it was analysed the main characteristics as organoleptic properties, weight of dry component, acidity, total and reducing sugars, ascorbic acid content and others. It was evidenced an increase in freshness and shelf-life extension by 5-7 days for strawberries and up to two weeks for cherries without any significant changes in the values of the considered parameters. Otherwise, for the applied doses, the electron-beam irradiation did not produce any significant changes in the values of fruit characteristic parameters. The results lead to the conclusion that the electron-beam irradiation is a good technological solution for fresh fruit processing. (Author) 1 Tab., 7 Refs

Particle beams and plasmas

International Nuclear Information System (INIS)

Hofmann, A.; Messerschmid, E.; Lawson, J.D.

1976-01-01

These lectures present a survey of some of the concepts of plasma physics and look at some situations familiar to particle-accelerator physicists from the point of view of a plasma physicist, with the intention of helping to link together the two fields. At the outset, basic plasma concepts are presented, including definitions of a plasma, characteristic parameters, magnetic pressure and confinement. This is followed by a brief discussion on plasma kinetic theory, non-equilibrium plasma, and the temperature of moving plasmas. Examples deal with beams in the CERN Intersecting Storage Rings as well as with non-steady beams in cyclic accelerators and microwave tubes. In the final chapters, time-varying systems are considered: waves in free space and the effect of cylinder bounds, wave motion in cold stationary plasmas, and waves in plasmas with well-defined streams. The treatment throughout is informal, with emphasis on the essential physical properties of continuous beams in accelerators and storage rings in relation to the corresponding problems in plasma physics and microwave tubes. (Author)

Investigation of Beam Emittance and Beam Transport Line Optics on Polarization

Energy Technology Data Exchange (ETDEWEB)

Fiedler, Andrew [Northern Illinois U.; Syphers, Michael [Fermilab

2017-10-06

Effects of beam emittance, energy spread, optical parameters and magnet misalignment on beam polarization through particle transport systems are investigated. Particular emphasis will be placed on the beam lines being used at Fermilab for the development of the muon beam for the Muon g-2 experiment, including comparisons with the natural polarization resulting from pion decay, and comments on the development of systematic correlations among phase space variables.

Passive breath gating equipment for cone beam CT-guided RapidArc gastric cancer treatments

International Nuclear Information System (INIS)

Hu, Weigang; Li, Guichao; Ye, Jinsong; Wang, Jiazhou; Peng, Jiayuan; Gong, Min; Yu, Xiaoli; Studentski, Matthew T.; Xiao, Ying; Zhang, Zhen

2015-01-01

Background and purpose: To report preliminary results of passive breath gating (PBG) equipment for cone-beam CT image-guided gated RapidArc gastric cancer treatments. Material and methods: Home-developed PBG equipment integrated with the real-time position management system (RPM) for passive patient breath hold was used in CT simulation, online partial breath hold (PBH) CBCT acquisition, and breath-hold gating (BHG) RapidArc delivery. The treatment was discontinuously delivered with beam on during BH and beam off for free breathing (FB). Pretreatment verification PBH CBCT was obtained with the PBG-RPM system. Additionally, the reproducibility of the gating accuracy was evaluated. Results: A total of 375 fractions of breath-hold gating RapidArc treatments were successfully delivered and 233 PBH CBCTs were available for analysis. The PBH CBCT images were acquired with 2–3 breath holds and 1–2 FB breaks. The imaging time was the same for PBH CBCT and conventional FB CBCT (60 s). Compared to FB CBCT, the motion artifacts seen in PBH CBCT images were remarkably reduced. The average BHG RapidArc delivery time was 103 s for one 270-degree arc and 269 s for two full arcs. Conclusions: The PBG-RPM based PBH CBCT verification and BHG RapidArc delivery was successfully implemented clinically. The BHG RapidArc treatment was accomplished using a conventional RapidArc machine with high delivery efficiency

Control and monitoring systems for electron beam flue gas treatment technology

International Nuclear Information System (INIS)

Chmielewski, A.G.; Licki, J.; Mazurekc, J.; Nelskic, L.; Sobolewskic, L.

2011-01-01

The reliable and accurate measurements of gas parameters in essential points of industrial plant are necessary for its proper operation and control. Natural flue gases there are only at the inlet. At other points of plant gas parameters are strongly modified by process control system. The principal role of process monitoring system is to provide the Computer System for Monitoring and Control with continuous recording of process parameters. The main goal of control system is to obtain the optimal SO 2 and NO x removal efficiencies by control of amount of spray water at the spray cooler, amount of NH 3 injection to flue gas and adjustment of electron beam current. The structure of the process control system is based on algorithms describing functional dependence of SO 2 and NO x removal efficiencies. The best available techniques should be applied for measurements of flue gases parameters at essential points of installation and for digital control system to assist plant operators in the analysis and optimization of plant operation, including integrated emission control. (author)

Control and monitoring systems for electron beam flue gas treatment technology

Energy Technology Data Exchange (ETDEWEB)

Chmielewski, A. G. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Licki, J. [Institute of Atomic Energy, Otwock-Świerk (Poland); Mazurekc, J.; Nelskic, L.; Sobolewskic, L. [Dolna Odra Group, Pomorzany Power Plant, Szczecin (Poland)

2011-07-01

The reliable and accurate measurements of gas parameters in essential points of industrial plant are necessary for its proper operation and control. Natural flue gases there are only at the inlet. At other points of plant gas parameters are strongly modified by process control system. The principal role of process monitoring system is to provide the Computer System for Monitoring and Control with continuous recording of process parameters. The main goal of control system is to obtain the optimal SO{sub 2} and NO{sub x} removal efficiencies by control of amount of spray water at the spray cooler, amount of NH{sub 3} injection to flue gas and adjustment of electron beam current. The structure of the process control system is based on algorithms describing functional dependence of SO{sub 2} and NO{sub x} removal efficiencies. The best available techniques should be applied for measurements of flue gases parameters at essential points of installation and for digital control system to assist plant operators in the analysis and optimization of plant operation, including integrated emission control. (author)

High power electron accelerators for flue gas treatment

International Nuclear Information System (INIS)

Zimek, Z.

2011-01-01

Flue gas treatment process based on electron beam application for SO 2 and NO x removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

Analysis of a large number of clinical studies for breast cancer radiotherapy: estimation of radiobiological parameters for treatment planning

International Nuclear Information System (INIS)

Guerrero, M; Li, X Allen

2003-01-01

Numerous studies of early-stage breast cancer treated with breast conserving surgery (BCS) and radiotherapy (RT) have been published in recent years. Both external beam radiotherapy (EBRT) and/or brachytherapy (BT) with different fractionation schemes are currently used. The present RT practice is largely based on empirical experience and it lacks a reliable modelling tool to compare different RT modalities or to design new treatment strategies. The purpose of this work is to derive a plausible set of radiobiological parameters that can be used for RT treatment planning. The derivation is based on existing clinical data and is consistent with the analysis of a large number of published clinical studies on early-stage breast cancer. A large number of published clinical studies on the treatment of early breast cancer with BCS plus RT (including whole breast EBRT with or without a boost to the tumour bed, whole breast EBRT alone, brachytherapy alone) and RT alone are compiled and analysed. The linear quadratic (LQ) model is used in the analysis. Three of these clinical studies are selected to derive a plausible set of LQ parameters. The potential doubling time is set a priori in the derivation according to in vitro measurements from the literature. The impact of considering lower or higher T pot is investigated. The effects of inhomogeneous dose distributions are considered using clinically representative dose volume histograms. The derived LQ parameters are used to compare a large number of clinical studies using different regimes (e.g., RT modality and/or different fractionation schemes with different prescribed dose) in order to validate their applicability. The values of the equivalent uniform dose (EUD) and biologically effective dose (BED) are used as a common metric to compare the biological effectiveness of each treatment regime. We have obtained a plausible set of radiobiological parameters for breast cancer. This set of parameters is consistent with in vitro

Application of Modal Parameter Estimation Methods for Continuous Wavelet Transform-Based Damage Detection for Beam-Like Structures

Directory of Open Access Journals (Sweden)

Zhi Qiu

2015-02-01

Full Text Available This paper presents a hybrid damage detection method based on continuous wavelet transform (CWT and modal parameter identification techniques for beam-like structures. First, two kinds of mode shape estimation methods, herein referred to as the quadrature peaks picking (QPP and rational fraction polynomial (RFP methods, are used to identify the first four mode shapes of an intact beam-like structure based on the hammer/accelerometer modal experiment. The results are compared and validated using a numerical simulation with ABAQUS software. In order to determine the damage detection effectiveness between the QPP-based method and the RFP-based method when applying the CWT technique, the first two mode shapes calculated by the QPP and RFP methods are analyzed using CWT. The experiment, performed on different damage scenarios involving beam-like structures, shows that, due to the outstanding advantage of the denoising characteristic of the RFP-based (RFP-CWT technique, the RFP-CWT method gives a clearer indication of the damage location than the conventionally used QPP-based (QPP-CWT method. Finally, an overall evaluation of the damage detection is outlined, as the identification results suggest that the newly proposed RFP-CWT method is accurate and reliable in terms of detection of damage locations on beam-like structures.

Dose measurements in the treatment of mycosis fungoides with total skin irradiation using a 4 MeV electron beam

Energy Technology Data Exchange (ETDEWEB)

Poli, M.E.R. [Hospital Real e Benemerita Sociedade Portuguesa de Beneficencia (Brazil); Todo, A.S.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, CNEN/SP Travessa R, Sao Paulo (Brazil)

2000-05-01

The total skin irradiation (TSI) is one of the most efficient techniques in the treatment administered with curative intent of the mycosis fungoides. The cure may be obtained in 10% to 40% of cases. The original Stanford University technique, created in 1960, was applied in a 4.8 MeV linear accelerator, that provided 2.5 MeV electrons in the patient, by the use of 4 couple beams with the patient placed in front of the beam, 3 meters distant from the apparatus. In this work we describe a 4 MeV electrons beam treatment method. We intend to improve the uniformity of the dose in the patient, as well, to reduce the problems with the overlapping treatment fields, that occurs in conventional treatment that uses 1 meter of focus-skin distance, and the treatment time to the patient. Only one modification was done in the apparatus: the dose rate for this treatment was doubled. The patient is placed on a rotative base and he assumes successively 6 positions: stand up and perpendicular to the beam, distant 2.83 meters from the gantry, with 60 degrees of interval between the rotations. In each position, the patient receives a couple of beams (the beam angulation is 19.5 degrees above the transversal axis in the middle of the patient and 19.5 degrees below it). The dosimetric data obtained were compared to the international protocols (AAPM). The delivered doses in the patient were measured with thermoluminescent dosimeters placed on skin surface and with Kodak XV-2 films placed between different slabs of an anthropomorphic phantom. The dose distribution in the phantom shows a good uniformity, in all thickness of interest, so it is possible to use this technique in the treatment of the mycosis fungoides as well Kaposi's sarcoma. (author)

Determination of the quality index (Q) for photon beams at arbitrary field sizes.

Science.gov (United States)

Sauer, Otto A

2009-09-01

A commonly used beam quality index (Q) for high-energy photon beams is the tissue phantom ratio (TPR20,10) for a square field of 10 x 10 cm2 and SDD of 100 cm. On some specialized radiotherapy treatment equipment such a reference collimator setting is not achievable. Likewise a flat beam profile, not explicitly required in dosimetry protocols, but certainly influences the measurement of Q, is not always produced. In this work, a method was developed in order to determine Q at any field size, especially for small and nonflattened beams. An analytical relationship was derived between TPR20,10 for arbitrary field sizes and Q [the TPR20,10 (10 x 10 cm2)] as quality index. The proposed model equation was fitted to the measured and published data in order to achieve three general fit parameters. The procedure was then tested with published data from TomoTherapy and CyperKnife treatment devices. For standard flattened photon fields, the uncertainty in Q measured at any field size using the parameters derived from this study is better than 1%. In flattening-filter free beams, the proposed procedure results in a reliable Q for any field size setting. A method is introduced and successfully tested in order to measure the beam quality under nonstandard conditions. It can be used, e.g., to get energy dependent correction factors as tabulated in dosimetry codes of practice even if standard conditions are not adjustable.

Sci—Sat AM: Stereo — 04: Evaluation of VMAT interplay effect for lung SABR using TrueBeam 10XFFF beam

International Nuclear Information System (INIS)

Huang, V; Thomas, SD; Teke, T

2014-01-01

During a VMAT treatment delivery, the interplay effect between the moving target and varying machine parameters result in dose distributions that are different from those initially planned. In this work, we investigate this effect for lung SABR by using 4D dose calculation derived from the Varian TrueBeam trajectory log file. The impact of treatment start phase is also evaluated. A QUASAR™ respiratory motion phantom was scanned with motion amplitudes of 0.4, 1, 2 and 3 cm with a 4 second period. MIP and the average dataset were generated from the 4DCT. A static CT was also acquired with the tumor in its centre position. Plans were optimized with 10X FFF beam until PTV and fictitious critical structures met the dose constraints. Ten temporally interleaved plans were constructed with the temporal machine parameter information from the trajectory log file. Ten plans were calculated with isocentre shifts to simulate respiratory motion and then summed. For each motion amplitude, three separate sum plans were created with various phase shifts (no phase shift, maximum inhalation and maximum exhalation) to assess the impact of treatment start phase. For all the phase shifts investigated, the DVH for PTV demonstrated good dose coverage. However, a careful review of slice by slice plan comparison indicates dose “holes” are observed within PTV. The PTV dose difference between various treatment start phases can be as high as 19%. This assumes all treatment fractions have identical treatment start phase. Our future work includes evaluation of interplay effect for various breathing periods

Status report on treatment planning with the fast neutron beam at Hamburg-Eppendorf

International Nuclear Information System (INIS)

Hess, A.; Schmidt, R.; Franke, H.D.

1981-01-01

For treatment planning with the fast neutron beam (DT, 14 MeV) at the Radiotherapy Department of the University Hospital Hamburg-Eppendorf the decrement line method is applied to compute isodose curves (total beam or neutrons and gamma-rays separately). The isodose curves are generated by a measured depth dose distribution and one lateral dose distribution at 10 cm phantom depth assuming two crossing points of the decrement lines at the edges of the collimator. By this method isodose charts have been generated for all available field sizes at 80 cm SSD. For the determination of depth dose values at different SSD a modified inverse square law has to be taken into account. Computerized treatment plans are calculated with the same technique used by the SIDOS-U1 (Siemens) planning system. (orig.)

Dissipative effects in the beam-beam interaction of intersecting storage rings

International Nuclear Information System (INIS)

Ford, J.; Vivaldi, F.

1982-01-01

This proposal seeks continuing support for an ongoing research investigation of various dynamical instabilities which arise in high energy intersecting storage rings due to the beam-beam interaction. Although the dissipative effect of radiation in beam-beam machines is anticipated to be a dominant feature affecting stability in the dynamics of colliding beams of heavy particles, almost nothing is known regarding the stability problem in many-dimensional dissipative systems. The work proposed here will extend the earlier computations on weak instabilities in many-dimensional beam-beam models to include the effect of dissipation. The object of this research is to obtain conditions for global beam stability over long time scales as a function of the machine parameters

BNS damping of beam breakup instability

International Nuclear Information System (INIS)

Stupakov, G.V.

1997-08-01

The author studies BNS damping of the beam breakup instability in a simple model assuming a constant beam energy, flat bunch distribution, and a smooth transverse focusing. The model allows an analytic solution for a constant and linear wake functions. Scaling dimensionless parameters are derived and the beam dynamics is illustrated for the range of parameters relevant to the Stanford Linear Collider

Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

International Nuclear Information System (INIS)

Duarte, C.L.; Ribeiro, M.A.; Oikawa, H.; Mori, M.N.; Napolitano, C.M.; Galvão, C.A.

2012-01-01

The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH. - Highlights: ► We study the enzymatic hydrolysis of cellulose and hemicellulose in sugarcane bagasse. ► We study the combination of three pretreatments: electron beam processing, EBP followed by hydrothermal and by diluted acid treatment. ► The electron beam processing increased the enzymatic hydrolysis from 8% to 15% with 20 kGy. ► The enzymes used were commercial preparations, as Celluclast 1.5 L and β-glycosidase. ► The EBP with 50 kGy increased on 20% the yield of EH of cellulose after TH and 30% after AH.

Advances in 4D treatment planning for scanned particle beam therapy - report of dedicated workshops.

Science.gov (United States)

Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

2014-12-01

We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue.

Characterizing the combinatorial beam angle selection problem

Science.gov (United States)

Bangert, Mark; Ziegenhein, Peter; Oelfke, Uwe

2012-10-01

The beam angle selection (BAS) problem in intensity-modulated radiation therapy is often interpreted as a combinatorial optimization problem, i.e. finding the best combination of η beams in a discrete set of candidate beams. It is well established that the combinatorial BAS problem may be solved efficiently with metaheuristics such as simulated annealing or genetic algorithms. However, the underlying parameters of the optimization process, such as the inclusion of non-coplanar candidate beams, the angular resolution in the space of candidate beams, and the number of evaluated beam ensembles as well as the relative performance of different metaheuristics have not yet been systematically investigated. We study these open questions in a meta-analysis of four strategies for combinatorial optimization in order to provide a reference for future research related to the BAS problem in intensity-modulated radiation therapy treatment planning. We introduce a high-performance inverse planning engine for BAS. It performs a full fluence optimization for ≈3600 treatment plans per hour while handling up to 50 GB of dose influence data (≈1400 candidate beams). For three head and neck patients, we compare the relative performance of a genetic, a cross-entropy, a simulated annealing and a naive iterative algorithm. The selection of ensembles with 5, 7, 9 and 11 beams considering either only coplanar or all feasible candidate beams is studied for an angular resolution of 5°, 10°, 15° and 20° in the space of candidate beams. The impact of different convergence criteria is investigated in comparison to a fixed termination after the evaluation of 10 000 beam ensembles. In total, our simulations comprise a full fluence optimization for about 3000 000 treatment plans. All four combinatorial BAS strategies yield significant improvements of the objective function value and of the corresponding dose distributions compared to standard beam configurations with equi

Characterizing the combinatorial beam angle selection problem

International Nuclear Information System (INIS)

Bangert, Mark; Ziegenhein, Peter; Oelfke, Uwe

2012-01-01

The beam angle selection (BAS) problem in intensity-modulated radiation therapy is often interpreted as a combinatorial optimization problem, i.e. finding the best combination of η beams in a discrete set of candidate beams. It is well established that the combinatorial BAS problem may be solved efficiently with metaheuristics such as simulated annealing or genetic algorithms. However, the underlying parameters of the optimization process, such as the inclusion of non-coplanar candidate beams, the angular resolution in the space of candidate beams, and the number of evaluated beam ensembles as well as the relative performance of different metaheuristics have not yet been systematically investigated. We study these open questions in a meta-analysis of four strategies for combinatorial optimization in order to provide a reference for future research related to the BAS problem in intensity-modulated radiation therapy treatment planning. We introduce a high-performance inverse planning engine for BAS. It performs a full fluence optimization for ≈3600 treatment plans per hour while handling up to 50 GB of dose influence data (≈1400 candidate beams). For three head and neck patients, we compare the relative performance of a genetic, a cross-entropy, a simulated annealing and a naive iterative algorithm. The selection of ensembles with 5, 7, 9 and 11 beams considering either only coplanar or all feasible candidate beams is studied for an angular resolution of 5°, 10°, 15° and 20° in the space of candidate beams. The impact of different convergence criteria is investigated in comparison to a fixed termination after the evaluation of 10 000 beam ensembles. In total, our simulations comprise a full fluence optimization for about 3000 000 treatment plans. All four combinatorial BAS strategies yield significant improvements of the objective function value and of the corresponding dose distributions compared to standard beam configurations with equi

Extraction of electron beam dose parameters from EBT2 film data scored in a mini phantom.

Science.gov (United States)

O'Reilly, Dedri; Smit, Cobus J L; du Plessis, Freek C P

2013-09-01

Quality assurance of medical linear accelerators includes dosimetric parameter measurement of therapeutic electron beams e.g. relative dose at a depth of 80% (R₈₀). This parameter must be within a tolerance of 0.2 cm of the declared value. Cumbersome water tank measurements can be regarded as a benchmark to measure electron depth dose curves. A mini-phantom was designed and built, in which a strip of GAFCHROMIC® EBT2 film could be encased tightly for electron beam depth dose measurement. Depth dose data were measured for an ELEKTA Sl25 MLC, ELEKTA Precise, and ELEKTA Synergy (Elekta Oncology Systems, Crawley, UK) machines. The electron beam energy range was between 4 and 22 MeV among the machines. A 10 × 10 cm² electron applicator with 95 cm source-surface-distance was used on all the machines. 24 h after irradiation, the EBT2 film strips were scanned on Canon CanoScan N670U scanner. Afterwards, the data were analysed with in-house developed software that entailed optical density to dose conversion, and optimal fitting of the PDD data to de-noise the raw data. From the PDD data R₈₀ values were solved for and compared with acceptance values. A series of tests were also carried out to validate the use of the scanner for film Dosimetry. These tests are presented in this study. It was found that this method of R₈₀ evaluation was reliable with good agreement with benchmark water tank measurements using a commercial parallel plate ionization chamber as the radiation detector. The EBT2 film data yielded R₈₀ values that were on average 0.06 cm different from benchmark water tank measured R₈₀ values.

Structure-phase states evolution in Al-Si alloy under electron-beam treatment and high-cycle fatigue

International Nuclear Information System (INIS)

Konovalov, Sergey; Alsaraeva, Krestina; Gromov, Victor; Semina, Olga; Ivanov, Yurii

2015-01-01

By methods of scanning and transmission electron diffraction microscopy the analysis of structure-phase states and defect substructure of silumin subjected to high-intensity electron beam irradiation in various regimes and subsequent fatigue loading up to failure was carried out. It is revealed that the sources of fatigue microcracks are silicon plates of micron and submicron size are not soluble in electron beam processing. The possible reasons of the silumin fatigue life increase under electron-beam treatment are discussed

Fast automatic system for measurements of beam parameters of the MMF linac

International Nuclear Information System (INIS)

Reinhardt-Nickulin, P.; Bragin, S.; Ilinsky, N.; Senichev, Yu.

1992-01-01

Fast transverse beam profile and current monitoring systems have been tested at the Linear Accelerator of Moscow Meson Factory. The signals for each system are derived from multiwire secondary emission chamber and beam current transformer. Each beam pulse is digitized by fast ADC's. There are two modes for systems. First one is for detailed beam adjustment and second one is for normal 100 Hz rate of the MMF Linac. Essential features of the hardware, software, data acquisition, measurement accuracy and beam results are presented. (author)

Long-range beam-beam experiments in the relativistic heavy ion collider

International Nuclear Information System (INIS)

Calaga, R; Fischer, W; Milas, N; Robert-Demolaize, G

2014-01-01

Long-range beam-beam effects are a potential limit to the LHC performance with the nominal design parameters, and certain upgrade scenarios under discussion. To mitigate long-range effects, current carrying wires parallel to the beam were proposed and space is reserved in the LHC for such wires. Two current carrying wires were installed in RHIC to study the effect of strong long-range beam-beam effects in a collider, as well as test the compensation of a single long-range interaction. The experimental data were used to benchmark simulations. We summarize this work

Electron beam treatment of toxic volatile organic compounds and dioxins

International Nuclear Information System (INIS)

Kojima, Takuji

2006-01-01

Considerations of wastes based on the reduction, reuse and recycle in daily life are primary measures to conserve our environment, but the control technology is necessary to support these measures. The electron beam (EB) process is promising as an advanced purification process having advantages such as a quick treatment of big volume gas, applicability even for very low concentration pollutants as the further purification at the downstream of existing process, and decomposition of pollutants into non-toxic substances by one process. The EB technology has been developed for treatment of toxic volatile organic compounds (VOCs) in ventilation gas and dioxins in solid waste incineration flue gas. (author)

Fractional Fourier transform for confluent hypergeometric beams

International Nuclear Information System (INIS)

Tang, Bin; Jiang, Chun; Zhu, Haibin

2012-01-01

Based on the definition of the fractional Fourier transform (FRFT) in the cylindrical coordinate system, the propagation properties of a new family of paraxial laser beams named confluent hypergeometric (HyG) beams, of which intensity profile is similar to that for the Bessel modes, passing through FRFT optical systems have been studied in detail by some typical numerical examples. The results indicate that the normalized intensity distribution of a HyG beam in the FRFT plane is closely related to not only the fractional order p but also the beam parameters m,n, and focal length f. -- Highlights: ► We study the propagation of a HyG beam through FRFT optical systems. ► The intensity of the beam in the FRFT plane is closely related to some parameters. ► We can control the properties of HyG beams by properly choosing the parameters.

Beam tuning and stabilization using beam phase measurements at GANIL

International Nuclear Information System (INIS)

Chabert, A.; Loyer, F.; Sauret, J.

1984-06-01

Owing to the great sensitivity of the beam phase to the various parameters, on line beam phase measurements proved to be a very efficient way of tuning and stabilizing the beam of the multi-accelerator complex. We recall the system which allows to obtain the different kinds of accurate measurements we need and describe the main applications: - tuning process (buncher and SSC's RF phase determination, setting of the required radial beam phase law in the SSC's); - stabilization of the beam by loops, the basic principle of which being to keep constant the beam central phase all along the machine by adjusting RF voltages or magnetic fields. Feedback loops are described and comparative results with and without feedback are given

Comparison of three methods reducing the beam parameter product of a laser diode stack for long range laser illumination applications

Science.gov (United States)

Lutz, Yves; Poyet, Jean-Michel; Metzger, Nicolas

2013-10-01

Laser diode stacks are interesting laser sources for active imaging illuminators. They allow the accumulation of large amounts of energy in multi-pulse mode, which is well suited for long-range image recording. Even when laser diode stacks are equipped with fast-axis collimation (FAC) and slow-axis collimation (SAC) microlenses, their beam parameter product (BPP) are not compatible with a direct use in highly efficient and compact illuminators. This is particularly true when narrow divergences are required such as for long range applications. To overcome these difficulties, we conducted investigations in three different ways. A first near infrared illuminator based on the use of conductively cooled mini-bars was designed, realized and successfully tested during outdoor experimentations. This custom specified stack was then replaced in a second step by an off-the-shelf FAC + SAC micro lensed stack where the brightness was increased by polarization overlapping. The third method still based on a commercial laser diode stack uses a non imaging optical shaping principle resulting in a virtually restacked laser source with enhanced beam parameters. This low cost, efficient and low alignment sensitivity beam shaping method allows obtaining a compact and high performance laser diode illuminator for long range active imaging applications. The three methods are presented and compared in this paper.

Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

Science.gov (United States)

Chundong, HU; Yongjian, XU; Yuanlai, XIE; Yahong, XIE; Lizhen, LIANG; Caichao, JIANG; Sheng, LIU; Jianglong, WEI; Peng, SHENG; Zhimin, LIU; Ling, TAO; the NBI Team

2018-04-01

Two sets of neutral beam injectors (NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with in-depth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that (1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline, (2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and (3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.

Modelling of treatment couch top with prowess panther treatment planning system for external beam radiotherapy

International Nuclear Information System (INIS)

Owusu-Agyapong, Linus

2016-07-01

The aim of this work is to evaluate the attenuation effects of a treatment couch and to alternatively model the couch top material with a Prowess Panther treatment planning system which does not support couch top modelling. The Hounsfield Unit classification of the couch structure was determined using a PMMA phantom by comparing ion chamber measurements with the dose forecasted by the treatment planning system (TPS). The transmission factor (TF) of the couch top was determined and was used as a TF for a treatment accessory that represented the treatment couch in the TPS. A treatment plan was done for various angles with and without the interference of the couch top and a simulated treatment was done using the PMMA phantom. Ion chamber measurement were made and compared with dose predicted by the TPS to evaluate the accuracy of the couch top modelling in the treatment planning system TPS. These investigations were done for various field sizes. The ideal set of HU for the couch was established to be -674. The measured TF was 0.956042 and the TPS calculated Transmission factor was 0.951456. The percentage difference between the measured and calculated TFs was 0.48% and this agrees perfectly with the IAEA recommended tolerance of 2%. Relative attenuation measurements were as high as 54.16% and as low as 0.63% for the beams that exited the couch before interacting with the phantom. In comparing couch modelling by couch simulation and couch TF insert, it was observed that the normalized doses were the same for 5×5 square field but deviated approximately 1% for the other field sizes. The highest deviation was observed at 10×10 square field. This study demonstrates that the couch simulation method of couch modelling is the best method that can be used to account for the effect of the treatment couch top on intersecting posterior beam fields. Thus, the attenuation effects of the treatment couch was effectively evaluated and the couch top material accurately modelled in

Assessment of radiotherapy photon beams: A practical and low cost methodology

International Nuclear Information System (INIS)

Reis, C.Q.M.; Nicolucci, P.

2017-01-01

Dosimetric properties of radiation beams used in radiotherapy are directly related to the energy spectrum produced by the treatment unit. Therefore, the development of methodologies to evaluate in a simple and accurate way the spectra of clinical beams can help establishing the quality control of the treatment. The purpose of this study is to present a practical and low cost methodology for determining primary spectra of radiotherapy photon beams from transmission measurements in attenuators of aluminum and using the method of the inverse Laplace transform. Monte Carlo simulation with PENELOPE code was used in order to evaluate and validate the reconstructed spectra by the calculation of dosimetric parameters that characterize the beam. Percentage depth dose values simulated with a 6 MV reconstructed spectrum shows maximum difference of 4.4% when compared to values measured at the corresponding clinical beam. For a 10 MV beam that difference was around 4.2%. Results obtained in this study confirm the adequacy of the proposed methodology for assessing primary photon beams produced by clinical accelerators. - Highlights: • Primary spectra of radiotherapy photon beams are determined from transmission measurements. • Monte Carlo calculations are used to evaluate the method of the inverse Laplace transform. • The proposed methodology is practical and of low cost for clinical purposes. • Results are in fair agreement with literature and clinical data.

High power electron accelerators for flue gas treatment

Energy Technology Data Exchange (ETDEWEB)

Zimek, Z. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

2011-07-01

Flue gas treatment process based on electron beam application for SO{sub 2} and NO{sub x} removal was successfully demonstrated in number of laboratories, pilot plants and industrial demonstration facilities. The industrial scale application of an electron beam process for flue gas treatment requires accelerators modules with a beam power 100-500 kW and electron energy range 0.8-1.5 MeV. The most important accelerator parameters for successful flue gas radiation technology implementation are related to accelerator reliability/availability, electrical efficiency and accelerator price. Experience gained in high power accelerators exploitation in flue gas treatment industrial demonstration facility was described and high power accelerator constructions have been reviewed. (author)

Laser ionization installation for measurement of atomic beam parameters

CERN Document Server

Tukhlibaev, O; Khalilov, E E; Alimov, U Z

2002-01-01

The design of the laser ionization installation for determination of the atomic beam intensity, density and spatial structure is described. The method of the atoms laser resonance staged photoionization is applied in the installation. The above installation consists of two lasers on the dyestuffs, the atomizer, the ionization system and the ion signals registration system. The results of studies on the spatial structure of the In atoms beam are presented. The proposed method provides for the spatial resolution at the level of 10-100 mu m

Treatment planning capability assessment of a beam shaping assembly for accelerator-based BNCT

International Nuclear Information System (INIS)

Herrera, M.S.; González, S.J.; Burlon, A.A.; Minsky, D.M.; Kreiner, A.J.

2011-01-01

Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) a theoretical study was performed to assess the treatment planning capability of different configurations of an optimized beam shaping assembly for such a facility. In particular this study aims at evaluating treatment plans for a clinical case of Glioblastoma.

The outcome of root-canal treatments assessed by cone-beam computed tomography

NARCIS (Netherlands)

Liang, Y.H.

2013-01-01

In this thesis, in-vivo and ex-vivo methods were utilized to assess the outcome of root canal treatments determined by cone-beam computed tomography (CBCT) and the reliability of the CBCT-findings. CBCT provided useful and reliable information leading to a better understanding of the outcome and

Guaranteed epsilon-optimal treatment plans with the minimum number of beams for stereotactic body radiation therapy

International Nuclear Information System (INIS)

Yarmand, Hamed; Winey, Brian; Craft, David

2013-01-01

Stereotactic body radiation therapy (SBRT) is characterized by delivering a high amount of dose in a short period of time. In SBRT the dose is delivered using open fields (e.g., beam’s-eye-view) known as ‘apertures’. Mathematical methods can be used for optimizing treatment planning for delivery of sufficient dose to the cancerous cells while keeping the dose to surrounding organs at risk (OARs) minimal. Two important elements of a treatment plan are quality and delivery time. Quality of a plan is measured based on the target coverage and dose to OARs. Delivery time heavily depends on the number of beams used in the plan as the setup times for different beam directions constitute a large portion of the delivery time. Therefore the ideal plan, in which all potential beams can be used, will be associated with a long impractical delivery time. We use the dose to OARs in the ideal plan to find the plan with the minimum number of beams which is guaranteed to be epsilon-optimal (i.e., a predetermined maximum deviation from the ideal plan is guaranteed). Since the treatment plan optimization is inherently a multi-criteria-optimization problem, the planner can navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing epsilon-optimality. We use mixed integer programming (MIP) for optimization. To reduce the computation time for the resultant MIP, we use two heuristics: a beam elimination scheme and a family of heuristic cuts, known as ‘neighbor cuts’, based on the concept of ‘adjacent beams’. We show the effectiveness of the proposed technique on two clinical cases, a liver and a lung case. Based on our technique we propose an algorithm for fast generation of epsilon-optimal plans. (paper)

Consistency check of photon beam physical data after recommissioning process

International Nuclear Information System (INIS)

Kadman, B; Chawapun, N; Ua-apisitwong, S; Asakit, T; Chumpu, N; Rueansri, J

2016-01-01

In radiotherapy, medical linear accelerator (Linac) is the key system used for radiation treatments delivery. Although, recommissioning was recommended after major modification of the machine by AAPM TG53, but it might not be practical in radiotherapy center with heavy workloads. The main purpose of this study was to compare photon beam physical data between initial commissioning and recommissioning of 6 MV Elekta Precise linac. The parameters for comparing were the percentage depth dose (PDD) and beam profiles. The clinical commissioning test cases followed IAEA-TECDOC-1583 were planned on REF 91230 IMRT Dose Verification Phantom by Philips’ Pinnacle treatment planning system. The Delta 4PT was used for dose distribution verification with 90% passing criteria of the gamma index (3%/3mm). Our results revealed that the PDDs and beam profiles agreed within a tolerance limit recommended by TRS430. Most of the point doses and dose distribution verification passed the acceptance criteria. This study showed the consistency of photon beam physical data after recommissioning process. There was a good agreement between initial commissioning and recommissioning within a tolerance limit, demonstrated that the full recommissioning process might not be required. However, in the complex treatment planning geometry, the initial data should be applied with great caution. (paper)

SU-E-J-72: Geant4 Simulations of Spot-Scanned Proton Beam Treatment Plans

Energy Technology Data Exchange (ETDEWEB)

Kanehira, T; Sutherland, K; Matsuura, T; Umegaki, K; Shirato, H [Hokkaido University, Sapporo, Hokkaido (Japan)

2014-06-01

Purpose: To evaluate density inhomogeneities which can effect dose distributions for real-time image gated spot-scanning proton therapy (RGPT), a dose calculation system, using treatment planning system VQA (Hitachi Ltd., Tokyo) spot position data, was developed based on Geant4. Methods: A Geant4 application was developed to simulate spot-scanned proton beams at Hokkaido University Hospital. A CT scan (0.98 × 0.98 × 1.25 mm) was performed for prostate cancer treatment with three or four inserted gold markers (diameter 1.5 mm, volume 1.77 mm3) in or near the target tumor. The CT data was read into VQA. A spot scanning plan was generated and exported to text files, specifying the beam energy and position of each spot. The text files were converted and read into our Geant4-based software. The spot position was converted into steering magnet field strength (in Tesla) for our beam nozzle. Individual protons were tracked from the vacuum chamber, through the helium chamber, steering magnets, dose monitors, etc., in a straight, horizontal line. The patient CT data was converted into materials with variable density and placed in a parametrized volume at the isocenter. Gold fiducial markers were represented in the CT data by two adjacent voxels (volume 2.38 mm3). 600,000 proton histories were tracked for each target spot. As one beam contained about 1,000 spots, approximately 600 million histories were recorded for each beam on a blade server. Two plans were considered: two beam horizontal opposed (90 and 270 degree) and three beam (0, 90 and 270 degree). Results: We are able to convert spot scanning plans from VQA and simulate them with our Geant4-based code. Our system can be used to evaluate the effect of dose reduction caused by gold markers used for RGPT. Conclusion: Our Geant4 application is able to calculate dose distributions for spot scanned proton therapy.

Structure and properties of the tool steel after electron beam treatment and following tempering

International Nuclear Information System (INIS)

Kozyr', I.G.; Borodin, R.V.; Voropaev, A.V.; Potapov, V.G.

1998-01-01

The possibility of changing the surface structure of chromium tool steel has been considered. The given properties were reached through the surface remelting by electron beam with following tempering of strengthened layer. The found distinguished zones with different structure and properties are formed as the result of this treatment. It is shown that for hipereutectoid steel the thermal furnace annealing at 300 deg C is necessary for strengthened surface layer forming after electron beam remelting. The same result can be had by means of short-term heating with electronic beam up to higher temperatures, but is not higher A 1 . The evaluation of temperature fields was carried out by numerical solution of nonstationary heat conductivity equation

A 62-MeV Proton Beam for the Treatment of Ocular Melanoma at Laboratori Nazionali del Sud-INFN

Science.gov (United States)

Cirrone, G. A. P.; Cuttone, G.; Lojacono, P. A.; Lo Nigro, S.; Mongelli, V.; Patti, I. V.; Privitera, G.; Raffaele, L.; Rifuggiato, D.; Sabini, M. G.; Salamone, V.; Spatola, C.; Valastro, L. M.

2004-06-01

At the Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS) in Catania, Italy, the first Italian protontherapy facility, named Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) has been built in collaboration with the University of Catania. It is based on the use of the 62-MeV proton beam delivered by the K=800 Superconducting Cyclotron installed and working at INFN-LNS since 1995. The facility is mainly devoted to the treatment of ocular diseases like uveal melanoma. A beam treatment line in air has been assembled together with a dedicated positioning patient system. The facility has been in operation since the beginning of 2002 and 66 patients have been successfully treated up to now. The main features of CATANA together with the clinical and dosimetric features will be extensively described; particularly, the proton beam line, that has been entirely built at LNS, with all its elements, the experimental transversal and depth dose distributions of the 62-MeV proton beam obtained for a final collimator of 25-mm diameter and the experimental depth dose distributions of a modulated proton beam obtained for the same final collimator. Finally, the clinical results over 1 yr of treatments, describing the features of the treated diseases will be reported.

Influence of pulsed electron beam treatment on microstructure and properties of TA15 titanium alloy

International Nuclear Information System (INIS)

Gao Yukui

2013-01-01

Highlights: ► The hardness changes were determined by nanoindention method. ► The surface modification by pulsed electron beam treatment was investigated. ► The mechanism was analyzed based on XRD and TEM investigations. ► The modification effects were focused at the surface layer hardness. - Abstract: The surface of TA15 titanium alloy was modified by pulsed electron beam and the hardness distribution along the treated surface layer was investigated by nanoindent technology. The grade characteristics were therefore analyzed by studying the distribution of hardness along surface layer of specimens. Moreover, the microstructure was investigated by OM, XRD and TEM techniques. Furthermore, the correlation of hardness to microstructure was analyzed. The results show that the grade fine grain microstructure is formed in the upper surface layer and the temperature grade or heat effect caused by pulsed electron beam treatment is the main reason to form grade fine grain microstructure in the surface layer.

Development of an irradiation device for electron beam wastewater treatment

International Nuclear Information System (INIS)

Rela, Paulo Roberto

2003-01-01

When domestic or industrial effluents with synthetic compounds are disposed without an adequate treatment, they impact negatively the environment with damages to aquatic life and for the human being. Both population and use of goods and services that contribute for the hazardous waste are growing. Hazardous regulations are becoming more restrictive and technologies, which do not destroy these products, are becoming less acceptable. The electron beam radiation process is an advanced oxidation process, that produces highly reactive radicals resulting in mineralization of the contaminant. In this work was developed an irradiation system in order to optimize the interaction of electron beam delivered from the accelerator with the processed effluent. It is composed by an irradiation device where the effluent presents to the electron beam in an up flow stream and a process control unit that uses the calorimetric principle. The developed irradiation device has a different configuration from the devices used by others researchers that are working with this technology. It was studied the technical and economic feasibility, comparing with the literature the results of the irradiation device demonstrated that it has a superior performance, becoming an process for use in disinfection and degradation of hazardous organic compounds of wastewater from domestic and industrial origin, contributing as an alternative technology for Sanitary Engineering. (author)

A map for the thick beam-beam interaction

International Nuclear Information System (INIS)

Irwin, J.; Chen, T.

1995-01-01

The authors give a closed-form expression for the thick beam-beam interaction for a small disruption parameter, as typical in electron-positron storage rings. The dependence on transverse angle and position of the particle trajectory as well as the longitudinal position of collision and the waist-modified shape of the beam distribution are included. Large incident angles, as are present for beam-halo particles or for large crossing-angle geometry, are accurately represented. The closed-form expression is well approximated by polynomials times the complex error function. Comparisons with multi-slice representations show even the first order terms are more accurate than a five slice representation, saving a factor of 5 in computation time

Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation

Science.gov (United States)

Magro, G.; Molinelli, S.; Mairani, A.; Mirandola, A.; Panizza, D.; Russo, S.; Ferrari, A.; Valvo, F.; Fossati, P.; Ciocca, M.

2015-09-01

This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5-30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo® TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus® chamber. An EBT3® film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size ratio. The accuracy of the TPS was proved to be clinically acceptable in all cases but very small and shallow volumes. In this contest, the use of MC to validate TPS results proved to be a reliable procedure for pre-treatment plan verification.

Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation

International Nuclear Information System (INIS)

Magro, G; Molinelli, S; Mairani, A; Mirandola, A; Panizza, D; Russo, S; Valvo, F; Fossati, P; Ciocca, M; Ferrari, A

2015-01-01

This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5–30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo ® TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus ® chamber. An EBT3 ® film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size ratio. The accuracy of the TPS was proved to be clinically acceptable in all cases but very small and shallow volumes. In this contest, the use of MC to validate TPS results proved to be a reliable procedure for pre-treatment plan verification. (paper)

4D in-beam positron emission tomography for verification of motion-compensated ion beam therapy

International Nuclear Information System (INIS)

Parodi, Katia; Saito, Nami; Chaudhri, Naved; Richter, Christian; Durante, Marco; Enghardt, Wolfgang; Rietzel, Eike; Bert, Christoph

2009-01-01

Purpose: Clinically safe and effective treatment of intrafractionally moving targets with scanned ion beams requires dedicated delivery techniques such as beam tracking. Apart from treatment delivery, also appropriate methods for validation of the actual tumor irradiation are highly desirable. In this contribution the feasibility of four-dimensionally (space and time) resolved, motion-compensated in-beam positron emission tomography (4DibPET) was addressed in experimental studies with scanned carbon ion beams. Methods: A polymethyl methracrylate block sinusoidally moving left-right in beam's eye view was used as target. Radiological depth changes were introduced by placing a stationary ramp-shaped absorber proximal of the moving target. Treatment delivery was compensated for motion by beam tracking. Time-resolved, motion-correlated in-beam PET data acquisition was performed during beam delivery with tracking the moving target and prolonged after beam delivery first with the activated target still in motion and, finally, with the target at rest. Motion-compensated 4DibPET imaging was implemented and the results were compared to a stationary reference irradiation of the same treatment field. Data were used to determine feasibility of 4DibPET but also to evaluate offline in comparison to in-beam PET acquisition. Results: 4D in-beam as well as offline PET imaging was found to be feasible and offers the possibility to verify the correct functioning of beam tracking. Motion compensation of the imaged β + -activity distribution allows recovery of the volumetric extension of the delivered field for direct comparison with the reference stationary condition. Observed differences in terms of lateral field extension and penumbra in the direction of motion were typically less than 1 mm for both imaging strategies in comparison to the corresponding reference distributions. However, in-beam imaging retained a better spatial correlation of the measured activity with the delivered

Liquid waste treatment plant with e-beam

International Nuclear Information System (INIS)

Han, Bumsoo; Kim, Jinkyu; Kim, Yuri

2003-01-01

Global withdrawals of water to satisfy human demands have grown dramatically in this century. Between 1900 and 1995, water consumption increased by over six times, more than double the rate of population growth. This rapid growth in water demand is due to the increasing reliance on irrigation to achieve food security, the growth of industrial uses, and the increasing use per capita for domestic purposes. Given the seriousness of the situation and future risk of crises, there is an urgent need to develop the water-efficient technologies including economical treatment methods of wastewater and polluted water. In the laboratory of EB-TECH Co., many industrial wastewater including leachate from landfill area, wastewater from papermill, dyeing complex, petrochemical processes, etc. are under investigation with electron beam irradiation. For the study of treating dyeing wastewater combined with conventional facilities, an electron beam pilot plant for treating 1,000 m 3 /day of wastewater from 80,000 m 3 /day of total dyeing wastewater has constructed and operated in Taegu Dyeing Industrial Complex. A commercial plant for re-circulation of wastewater from Papermill Company is also designed for Pan Asia Paper Co. Cheongwon Mill, and after the successful installation, up to 80% of wastewater could be re-used in paper producing process. The method for the removal of heavy metals from wastewater and other technologies are developed with the joint works with Institute of Physical Chemistry (IPC) of Russian Academy of Sciences. (author)

Some recent developments in treatment planning software and methodology for BNCT

International Nuclear Information System (INIS)

Nigg, D.W.; Wheeler, F.J.; Wessol, D.E.; Wemple, C.A.; Babcock, R.; Capala, J.

1996-01-01

Over the past several years/the Idaho National Engineering Laboratory (INEL) has led the development of a unique, internationally-recognized set of software modules (BNCT rtpe) for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT). The computational capability represented by this software is essential to the proper administration of all forms of radiotherapy for cancer. Such software addresses the need to perform pretreatment computation and optimization of the radiation dose distribution in the target volume. This permits the achievement of the optimal therapeutic ratio (tumor dose relative to critical normal tissue dose) for each individual patient via a systematic procedure for specifying the appropriate irradiation parameters to be employed for a given treatment. These parameters include angle of therapy beam incidence, beam aperture and shape,and beam intensity as a function of position across the beam front. The INEL software is used for treatment planning in the current series of human glioma trials at Brookhaven National Laboratory (BNL) and has also been licensed for research and developmental purposes to several other BNCT research centers in the US and in Europe

Some recent developments in treatment planning software and methodology for BNCT

International Nuclear Information System (INIS)

Nigg, D.W.; Wheeler, F.J.; Wessol, D.E.

1996-01-01

Over the past several years the Idaho National Engineering Laboratory (INEL) has led the development of a unique, internationally-recognized set of software modules (BNCT-rtpe) for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT). The computational capability represented by this software is essential to the proper administration of all forms of radiotherapy for cancer. Such software addresses the need to perform pretreatment computation and optimization of the radiation dose distribution in the target volume. This permits the achievement of the optimal therapeutic ratio (tumor dose relative to critical normal tissue dose) for each individual patient via a systematic procedure for specifying the appropriate irradiation parameters to be employed for a given treatment. These parameters include angle of therapy beam incidence, beam aperture and shape, and beam intensity as a function of position across the beam front. The INEL software is used for treatment planning in the current series of human glioma trials at Brookhaven National Laboratory (BNL) and has also been licensed for research and developmental purposes to several other BNCT research centers in the US and in Europe

Numerical Simulation of Beam-Beam Effects in the Proposed Electron-Ion Colider at Jefferson Lab

International Nuclear Information System (INIS)

Terzic, Balsa; Zhang, Yuhong

2010-01-01

One key limiting factor to a collider luminosity is beam-beam interactions which usually can cause serious emittance growth of colliding beams and fast reduction of luminosity. Such nonlinear collective beam effect can be a very serious design challenge when the machine parameters are pushed into a new regime. In this paper, we present simulation studies of the beam-beam effect for a medium energy ring-ring electron-ion collider based on CEBAF.