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

Design guidelines for flexural wave attenuation of slender beams with local resonators

International Nuclear Information System (INIS)

Liu, Yaozong; Yu, Dianlong; Li, Li; Zhao, Honggang; Wen, Jihong; Wen, Xisen

2007-01-01

The complex band structures and attenuation spectra of flexural waves in slender beams with periodically mounted local resonators are investigated with transfer matrix method. It is noteworthy that the frequency range and attenuation coefficient of the locally resonant gap become larger in complex band structures if larger resonators were used. But given the total add-on mass of resonators, the attenuation spectra of finite beams with large but few resonators do not demonstrate such phenomena because the attenuation needs several periods to establish. So with the view of application, a large number of small local resonators widely spread along the beam are preferred given the total add-on mass to the beam

Apparatus for minimizing radiation exposure and improving resolution in radiation imaging devices

International Nuclear Information System (INIS)

Ashe, J.B.; Williams, G.H.; Sypal, K.L.

1978-01-01

A collimator is disclosed for minimizing radiation exposure and improving resolution in radiation imaging devices. The collimator provides a penetrating beam of radiation from a source thereof, which beam is substantially non-diverging in at least one direction. In the preferred embodiment, the collimator comprises an elongated sandwich assembly of a plurality of layers of material exhibiting relatively high radiation attenuation characteristics, which attenuating layers are spaced apart and separated from one another by interleaved layers of material exhibiting relatively low radiation attenuation characteristics. The sandwich assembly is adapted for lengthwise disposition and orientation between a radiation source and a target or receiver such that the attenuating layers are parallel to the desired direction of the beam with the interleaved spacing layers providing direct paths for the radiation

Polymer composites with carbon nanotube for application of radiation attenuator in medical procedures

Energy Technology Data Exchange (ETDEWEB)

Fontainha, C.C.P.; Nunes, M.; Rosas, V.A., E-mail: crissia@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Anatomia e Imagem; Furtado, C.A.; Faria, L.O. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Medical radiology offers great benefit to patients, however, the radiation contributes for the workers and individuals exposure, significantly increasing dose to population. New attenuators materials have been widely investigated for radiation shielding to apply in medical procedures. Polymeric composites filled with attenuating metals and functionalized with carbon nanotubes (NTC) are being largely developed. In this work, composites were produced for radiation attenuation in radiodiagnostic imaging procedures. Two types of polymer matrices, polyvinylidene fluoride, PVDF, and its copolymer, poly(vinylidene-trifluorylene fluoride), P(VDF-TrFE), were filled bismuth oxide nanoparticles. Carbon nanotubes were added with different concentrations at the solution of attenuator metal under controlled magnetic stirring. The composites were characterized by differential heat flow scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and dispersive energy X-ray spectrometry (EDS) for thermal analysis. In this setup, one reference measure is directly exposed to the x-rays being diffracted by single crystal of Si (111). Another measure the attenuated beam is performed with the composite sample under detector. The samples present a good dispersion of the attenuator metal and the nanotube carbon. On the other hand, composites with PVDF matrix lost their plasticity, stiffening their structure, becoming brittle, even using the same methodology of synthesis. The P(VDF-Trfe) matrix showed better maleability than PVDF matrix. The cheaptube dispersion in the P(VDF-Trfe) matrix presented better than the 3100 carbon nanotubes. The attenuation for 8.047 keV monoenergetic photons was about 90% to 100 μm thickness for all composites. (author)

Polymer composites with carbon nanotube for application of radiation attenuator in medical procedures

International Nuclear Information System (INIS)

Fontainha, C.C.P.; Nunes, M.; Rosas, V.A.

2017-01-01

Medical radiology offers great benefit to patients, however, the radiation contributes for the workers and individuals exposure, significantly increasing dose to population. New attenuators materials have been widely investigated for radiation shielding to apply in medical procedures. Polymeric composites filled with attenuating metals and functionalized with carbon nanotubes (NTC) are being largely developed. In this work, composites were produced for radiation attenuation in radiodiagnostic imaging procedures. Two types of polymer matrices, polyvinylidene fluoride, PVDF, and its copolymer, poly(vinylidene-trifluorylene fluoride), P(VDF-TrFE), were filled bismuth oxide nanoparticles. Carbon nanotubes were added with different concentrations at the solution of attenuator metal under controlled magnetic stirring. The composites were characterized by differential heat flow scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and dispersive energy X-ray spectrometry (EDS) for thermal analysis. In this setup, one reference measure is directly exposed to the x-rays being diffracted by single crystal of Si (111). Another measure the attenuated beam is performed with the composite sample under detector. The samples present a good dispersion of the attenuator metal and the nanotube carbon. On the other hand, composites with PVDF matrix lost their plasticity, stiffening their structure, becoming brittle, even using the same methodology of synthesis. The P(VDF-Trfe) matrix showed better maleability than PVDF matrix. The cheaptube dispersion in the P(VDF-Trfe) matrix presented better than the 3100 carbon nanotubes. The attenuation for 8.047 keV monoenergetic photons was about 90% to 100 μm thickness for all composites. (author)

Minimal residual cone-beam reconstruction with attenuation correction in SPECT

International Nuclear Information System (INIS)

La, Valerie; Grangeat, Pierre

1998-01-01

This paper presents an iterative method based on the minimal residual algorithm for tomographic attenuation compensated reconstruction from attenuated cone-beam projections given the attenuation distribution. Unlike conjugate-gradient based reconstruction techniques, the proposed minimal residual based algorithm solves directly a quasisymmetric linear system, which is a preconditioned system. Thus it avoids the use of normal equations, which improves the convergence rate. Two main contributions are introduced. First, a regularization method is derived for quasisymmetric problems, based on a Tikhonov-Phillips regularization applied to the factorization of the symmetric part of the system matrix. This regularization is made spatially adaptive to avoid smoothing the region of interest. Second, our existing reconstruction algorithm for attenuation correction in parallel-beam geometry is extended to cone-beam geometry. A circular orbit is considered. Two preconditioning operators are proposed: the first one is Grangeat's inversion formula and the second one is Feldkamp's inversion formula. Experimental results obtained on simulated data are presented and the shadow zone effect on attenuated data is illustrated. (author)

Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

Science.gov (United States)

Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

2016-02-01

Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

Attenuation of a non-parallel beam of gamma radiation by thick shielding-application to the determination of the {sup 235}U enrichment with NaI detectors

Energy Technology Data Exchange (ETDEWEB)

Mortreau, Patricia [European Commission, Joint Research Centre, Institute for the Protection and Security of the Citizen, TP 800 Via Fermi, Ispra (Vatican City State, Holy See,) (Italy)]. E-mail: patricia.mortreau@jrc.it; Berndt, Reinhard [European Commission, Joint Research Centre, Institute for the Protection and Security of the Citizen, TP 800 Via Fermi, Ispra (VA) (Italy)

2005-09-21

The traditional method used to determine the Uranium enrichment by nondestructive analysis is based on the 'enrichment meter principle' [1]. It involves measuring the intensity of the 186 keV net peak area of {sup 235}U in 'quasi-infinite' samples. A prominent factor, which affects the peak intensity, is the presence of gamma absorbing material (e.g., container wall, detector cover) between the sample and the detector. Its effect is taken into consideration in a commonly called 'wall thickness' correction factor. Often calculated on the basis of approximations, its performance is adequate for small attenuation factors applicable to the case of narrow beams. However these approximations do not lead to precise results when wide non-parallel beams are attenuated through thick container walls. This paper is dedicated to the calculation by numerical integration of the geometrical correction factor (K {sub wtc}) which describes the effective mean path length of the radiation through the absorbing layer. This factor was calculated as a function of various measurement parameters (types and dimensions of the detector, of the collimator and of the shielding) for the most commonly used collimator shapes and detectors. Both coherent scattering (Rayleigh) and incoherent scattering (Compton) are taken into account for the calculation of the radiation interaction within the detector.

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

Attenuation maps for SPECT determined using cone beam transmission computed tomography

International Nuclear Information System (INIS)

Manglos, S.H.; Bassano, D.A.; Duxbury, C.E.; Capone, R.B.

1990-01-01

This paper presents a new method for measuring non-uniform attenuation maps, using a cone beam geometry CT scan acquired on a standard rotating gamma camera normally used for SPECT imaging. The resulting map is intended for use in non-uniform attenuation compensation of SPECT images. The method was implemented using a light-weight point source holder attached to the camera. A cone beam collimator may be used on the gamma camera, but the cone beam CT scans may also be acquired without collimator. In either implementation, the advantages include very high efficiency and resolution limited not by the collimator but by the intrinsic camera resolution (about 4 mm). Several phantoms tested the spatial uniformity, noise, linearity as a function of attenuation coefficient, and spatial resolution. Good quality attenuation maps were obtained, at least for the central slices where no truncation was present

Flexural wave attenuation in a sandwich beam with viscoelastic periodic cores

Science.gov (United States)

Guo, Zhiwei; Sheng, Meiping; Pan, Jie

2017-07-01

The flexural-wave attenuation performance of traditional constraint-layer damping in a sandwich beam is improved by using periodic constrained-layer damping (PCLD), where the monolithic viscoelastic core is replaced with two periodically alternating viscoelastic cores. Closed-form solutions of the wave propagation constants of the infinite periodic sandwich beam and the forced response of the corresponding finite sandwich structure are theoretically derived, providing computational support on the analysis of attenuation characteristics. In a sandwich beam with PCLD, the flexural waves can be attenuated by both Bragg scattering effect and damping effect, where the attenuation level is mainly dominated by Bragg scattering in the band-gaps and by damping in the pass-bands. Affected by these two effects, when the parameters of periodic cores are properly selected, a sandwich beam with PCLD can effectively reduce vibrations of much lower frequencies than that with traditional constrained-layer damping. The effects of the parameters of viscoelastic periodic cores on band-gap properties are also discussed, showing that the average attenuation in the desired frequency band can be maximized by tuning the length ratio and core thickness to proper values. The research in this paper could possibly provide useful information for the researches and engineers to design damping structures.

Iterative reconstruction with attenuation compensation from cone-beam projections acquired via nonplanar orbits

International Nuclear Information System (INIS)

Zeng, G.L.; Weng, Y.; Gullberg, G.T.

1997-01-01

Single photon emission computed tomography (SPECT) imaging with cone-beam collimators provides improved sensitivity and spatial resolution for imaging small objects with large field-of-view detectors. It is known that Tuy's cone-beam data sufficiency condition must be met to obtain artifact-free reconstructions. Even though Tuy's condition was derived for an attenuation-free situation, the authors hypothesize that an artifact-free reconstruction can be obtained even if the cone-beam data are attenuated, provided the imaging orbit satisfies Tuy's condition and the exact attenuation map is known. In the authors' studies, emission data are acquired using nonplanar circle-and-line orbits to acquire cone-beam data for tomographic reconstructions. An extended iterative ML-EM (maximum likelihood-expectation maximization) reconstruction algorithm is derived and used to reconstruct projection data with either a pre-acquired or assumed attenuation map. Quantitative accuracy of the attenuation corrected emission reconstruction is significantly improved

Measure of the attenuation curve of a beam of X-rays with TLD-100 dosimeters of LiF

International Nuclear Information System (INIS)

Bonzi, E. V.; Mainardi, R. T.; Germanier, A.; Delgado, V.

2011-10-01

The attenuation curve of a beam of X-rays represents the beam intensity in function of the attenuator thickness interposed between the source and the detector. To know with the major possible precision the attenuation curve is indispensable in procedures of spectral reconstruction. Their periodic measuring also offers valuable information on the correct operation of a tube of X-rays, diagnostic or therapy, when not have a specific detector for that activity. In this work was measured the attenuation curve of a tube of X-rays operated to 50 kV and 0.5 ma, using existent elements in any diagnostic or therapy laboratory with radiations. In the measures commercial aluminum foil was used, bent until 24 times and thermoluminescent dosimeters TLD 100 - LiF. Also, for comparison, was measured this attenuation curve with an ionization chamber brand Capintec model 192. Was determined by X-rays fluorescence the composition of the aluminium foil, since the present elements in the alloy can to affect the form of the attenuation curve. It is interesting to observe that these elements are in very low proportion (ppm) that they do not alter the attenuation capacity of the pure aluminium. Finally in a precision balance we weigh a big piece (30 cm x 100 cm) of aluminium foil and we obtained the thickness in g/c m2. It is possible to obtain attenuation curves of a beam of X-rays, with a high precision procedure and reproducibility. The use of TLD-100 dosimeters of LiF or similar makes that this activity was also quick and simple. (Author)

Broad beam X-rays attenuation in silicum glass

International Nuclear Information System (INIS)

Risticj, Dj.; Vukovicj, S.; Markovicj, P.

1987-01-01

Using broad beam geometry the attenuation for domestic silicum glass have been studied for constant X-ray potentials from 50 to 150 kV. The density of the silicium glass was 2,5x10 3 kg/m 3 . From the attenuation curves the half value layers were obtained. The use of this glass as the biological shield is pointed out. (author). 2 refs.; 2 tabs.; 2 figs

Characterization of a Cs-137 radiation beam for dosimeter calibrations in the CRCN-CO

International Nuclear Information System (INIS)

Baptista Neto, Annibal T.; Soares, Carlos M. de A.; Silva, Teogenes A. da; Correa, Rosangela da S.

2009-01-01

The Centro Regional de Ciencias Nucleares do Centro Oeste (CRCN-CO) has played an important role in the environmental radiation monitoring program in Goiania city. The reduce its dependence of others monitoring laboratories, the CRCN-CO acquired a model 28 JL Shepherd and Associates irradiation system with a 137 Cs source for calibrations and frequent quality control checks of radiation dosimeters. A characterization of the irradiation system was carried out with the reference standard dosimeters that are maintained by the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN). The laboratory surrounding areas were monitored to demonstrate the adequate radiation protection conditions and parameters as the radiation field size, beam uniformity and the level of the scatter radiation were investigated. Dosimetry of the 137 Cs radiation beam in terms of air kerma rate was carried out at many source-detector distances with 4 (four) different beam lead attenuators. Results demonstrated that in spite of the radiation shutter automation is strongly recommended, the irradiation system is adequate and it complies with the requirements to be used for dosimeter irradiations and calibrations for the purpose of radiation protection. (author)

Beam hardening: Analytical considerations of the effective attenuation coefficient of x-ray tomography

International Nuclear Information System (INIS)

Alles, J.; Mudde, R. F.

2007-01-01

Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving through a given, inhomogeneous material. On the basis of this one-to-one relation, it is useful to define a mean attenuation coefficient and study its decrease with depth. Our results are based on a novel parametrization of the energy dependence of the attenuation coefficient that allows for closed form evaluation of certain spectral integrals. This approach underpins the ad hoc semianalytical expressions given in the literature. An analytical model for the average attenuation coefficient is proposed that uses a simple fit of the attenuation coefficient as a function of the photon energy as input. It is shown that a simple extension of this model gives a rather good description of beam hardening for x-rays traveling through water

Result of radiation therapy of sino-nasal cancers using partial attenuation filter

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Hee; Kim, Ok Bae; Choi, Tae Jin [Keimyung University College of Medicine, Daegu (Korea, Republic of)

2007-06-15

This study was to evaluate the survival and pattern of failure after radiation therapy of sino-nasal cancer using partial attenuation filer and wedged beams and to help radiotherapy planning of sino-nasal cancer. Between February 1992 and March 2003, 17 patients with sino-nasal cancers underwent radiation therapy using partial attenuation filter at Dongsan Medical Center, Keimyung university. There were 9 male and 8 female patients. Patients' age ranged from 40 to 75 years (median 59 years). There were 10 patients of maxillary sinus cancer, 7 patients of nasal cancer. The histologic type was squamous cell carcinoma in 11, adenoid cystic carcinoma in 4 and olfactory neuroblastoma in 2. The distribution of clinical stage by the AJCC system was 3 for stage II, 7 for III and 6 for IV. The five patients were treated with radiation alone and 12 patients were treated with surgery and postoperative radiation therapy. The range of total radiation dose delivered to the primary tumor was from 44 to 76 Gy (median 60 Gy). The follow-up period ranged from 3 to 173 months with median of 78 months. The overall 2 year survival rate and disease free survival rate was 76.4%. The 5 year and 10 year survival rate were 76.4% and 45.6% and the 5 year and 10 year disease free survival rate was 70.6%. The 5 year disease free survival rate by treatment modality was 91.6% for postoperative radiation group and 20% for radiation alone group, statistical significance was found by treatment modality ({rho} = 0.006). There were no differences in survival by pathology and stage. There were local failure in 5 patients (29%) but no distant failure and no severe complication required surgical intervention. Radiation therapy of sino-nasal cancer using partial attenuation filter was safe and effective. Combined modality with conservative surgery and radiation therapy was more advisable to achieve loco-regional control in sino-nasal cancer. Also we considered high precision radiation therapy with

Study of radiation dose attenuation by skull bone in head during radiotherapy treatment using MCNP

Energy Technology Data Exchange (ETDEWEB)

Menezes, Artur F.; Boia, Leonardo S.; Trombetta, Debora M.; Martins, Maximiano C.; Reis Junior, Juraci P.; Silva, Ademir X., E-mail: ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Batista, Delano V.S., E-mail: delano@inca.gov.b [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

2011-07-01

In this study the MCNPX code was used to investigate possible influences of the attenuation beam by the surface bone during radiotherapy treatments of the skull. The computer simulation was performed on topographic image obtained from the National Cancer Institute, in Rio de Janeiro, database of patients treated with radiotherapy. The image segmentation process were performed using the SAPDI program developed to this purpose. The segmented image conversion for the input file recognized by MCNPX code was performed by SCAN2MCNP Software. The simulation was done using 10MeV Clinac 2300C spectrum considering two opposite parallel beams, with field size 2x2 and 4x4 cm{sup 2}, incident on a slice located above the eyes, containing two row of detectors positioned on the central region with a radius of 0.03 cm and arranged perpendicular to the radiation beams. After analyze the results, the relative error values in the range of 2 at 4% for the high dose region, and 26 at 37% for the low dose area were found, respectively. These differences were attributed to the radiation field attenuation on the bone surface at the entrance of the beam. It was observed that most situations on the high dose region the beam profile, from more realistic scenarios, became smaller than the one obtained when the tomography image was considered consisting of water. However for the low dose area the profile, obtained of the realistic situation, became higher than the one which was obtained when the tomography image was considered consisting of water. The results showed significant differences between both analyzed cases which show the need to use a correction factor by the treatment planning system used in radiotherapy services when the real chemical composition of patient head is unconsidered during the patient treatment planning. (author)

Study of radiation dose attenuation by skull bone in head during radiotherapy treatment using MCNP

International Nuclear Information System (INIS)

Menezes, Artur F.; Boia, Leonardo S.; Trombetta, Debora M.; Martins, Maximiano C.; Reis Junior, Juraci P.; Silva, Ademir X.; Batista, Delano V.S.

2011-01-01

In this study the MCNPX code was used to investigate possible influences of the attenuation beam by the surface bone during radiotherapy treatments of the skull. The computer simulation was performed on topographic image obtained from the National Cancer Institute, in Rio de Janeiro, database of patients treated with radiotherapy. The image segmentation process were performed using the SAPDI program developed to this purpose. The segmented image conversion for the input file recognized by MCNPX code was performed by SCAN2MCNP Software. The simulation was done using 10MeV Clinac 2300C spectrum considering two opposite parallel beams, with field size 2x2 and 4x4 cm 2 , incident on a slice located above the eyes, containing two row of detectors positioned on the central region with a radius of 0.03 cm and arranged perpendicular to the radiation beams. After analyze the results, the relative error values in the range of 2 at 4% for the high dose region, and 26 at 37% for the low dose area were found, respectively. These differences were attributed to the radiation field attenuation on the bone surface at the entrance of the beam. It was observed that most situations on the high dose region the beam profile, from more realistic scenarios, became smaller than the one obtained when the tomography image was considered consisting of water. However for the low dose area the profile, obtained of the realistic situation, became higher than the one which was obtained when the tomography image was considered consisting of water. The results showed significant differences between both analyzed cases which show the need to use a correction factor by the treatment planning system used in radiotherapy services when the real chemical composition of patient head is unconsidered during the patient treatment planning. (author)

Transient attenuation in optical fibers

International Nuclear Information System (INIS)

Hopkins, A.A.; Kelly, R.E.; Looney, L.D.; Lyons, P.B.

1984-01-01

Low and high energy pulsed electron beams were used to generate radiation-induced transient attenuation in high-OH, Suprasil core, PCS fibers, demonstrating the energy dependence of the radiation damage and recovery mechanisms. A radiation resistant low-OH fiber was studied and its performance contrasted to that of high-OH materials. Several fibers with differing core compositions were also studied

An FDK-like cone-beam SPECT reconstruction algorithm for non-uniform attenuated projections acquired using a circular trajectory

International Nuclear Information System (INIS)

Huang, Q; Zeng, G L; You, J; Gullberg, G T

2005-01-01

In this paper, Novikov's inversion formula of the attenuated two-dimensional (2D) Radon transform is applied to the reconstruction of attenuated fan-beam projections acquired with equal detector spacing and of attenuated cone-beam projections acquired with a flat planar detector and circular trajectory. The derivation of the fan-beam algorithm is obtained by transformation from parallel-beam coordinates to fan-beam coordinates. The cone-beam reconstruction algorithm is an extension of the fan-beam reconstruction algorithm using Feldkamp-Davis-Kress's (FDK) method. Computer simulations indicate that the algorithm is efficient and is accurate in reconstructing slices close to the central slice of the cone-beam orbit plane. When the attenuation map is set to zero the implementation is equivalent to the FDK method. Reconstructed images are also shown for noise corrupted projections

Attenuation of 10 MeV electron beam energy to achieve low doses does not affect Salmonella spp. inactivation kinetics

International Nuclear Information System (INIS)

Hieke, Anne-Sophie Charlotte; Pillai, Suresh D.

2015-01-01

The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D 10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV

Electromagnetic radiation from beam-plasma instabilities

International Nuclear Information System (INIS)

Stenzel, R.L.; Whelan, D.A.

1982-01-01

This chapter investigates the mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves. Electromagnetic radiation arises from both natural beam-plasma systems (e.g., type III solar bursts and kilometric radiation), and from man-made electron beams injected from rockets and spacecraft. A pulsed magnetized discharge plasma is produced with a 1 m diam. oxide-coated cathode and the discussed experiment is performed in the quiescent afterglow. The primary beam-plasma instability involves the excitation of electrostatic plasma waves. Electromagnetic radiation from the beam-plasma system is observed with microwave antennas outside the plasma (all probes removed) or with coax-fed dipoles which can be inserted radially and axially into the plasma. The physical process of mode coupling by which electromagnetic radiation is generated in an electrostatic beam-plasma instability is identified. The results are relevant to beam injection experiments from rockets or satellites into space plasmas. The limited penetration of the beam current into the plasma due to instabilities is demonstrated

Ketoconazole attenuates radiation-induction of tumor necrosis factor

Energy Technology Data Exchange (ETDEWEB)

Hallahan, D.E.; Virudachalam, S.; Kufe, D.W.; Weichselbaum, R.R. [Dana Farber Cancer Institute, Boston, MA (United States)

1994-07-01

Previous work has demonstrated that inhibitors of phospholipase A2 attenuate ionizing radiation-induced arachidonic acid production, protein kinase C activation, and prevent subsequent induction of the tumor necrosis factor gene. Because arachidonic acid contributes to radiation-induced tumor necrosis factor expression, the authors analyzed the effects of agents which alter arachidonate metabolism on the regulation of this gene. Phospholipase A2 inhibitors quinicrine, bromphenyl bromide, and pentoxyfylline or the inhibitor of lipoxygenase (ketoconazole) or the inhibitor of cycloxygenase (indomethacine) were added to cell culture 1 h prior to irradiation. Radiation-induced tumor necrosis factor gene expression was attenuated by each of the phospholipase A2 inhibitors (quinicrine, bromphenylbromide, and pentoxyfylline). Furthermore, ketoconazole attenuated X ray induced tumor necrosis factor gene expression. Conversely, indomethacin enhanced tumor necrosis factor expression following irradiation. The finding that radiation-induced tumor necrosis factor gene expression was attenuated by ketoconazole suggests that the lipoxygenase pathway participates in signal transduction preceding tumor necrosis factor induction. Enhancement of tumor necrosis factor expression by indomethacin following irradiation suggests that prostaglandins produced by cyclooxygenase act as negative regulators of tumor necrosis factor expression. Inhibitors of tumor necrosis factor induction ameliorate acute and subacute sequelae of radiotherapy. The authors propose therefore, that ketoconazole may reduce acute radiation sequelae such as mucositis and esophagitis through a reduction in tumor necrosis factor induction or inhibition of phospholipase A2 in addition to its antifungal activity. 25 refs., 2 figs.

Electromagnetic radiation from beam-plasma instabilities

Science.gov (United States)

Pritchett, P. L.; Dawson, J. M.

1983-01-01

A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.

Validation of attenuation, beam blockage, and calibration estimation methods using two dual polarization X band weather radars

Science.gov (United States)

Diederich, M.; Ryzhkov, A.; Simmer, C.; Mühlbauer, K.

2011-12-01

The amplitude a of radar wave reflected by meteorological targets can be misjudged due to several factors. At X band wavelength, attenuation of the radar beam by hydro meteors reduces the signal strength enough to be a significant source of error for quantitative precipitation estimation. Depending on the surrounding orography, the radar beam may be partially blocked when scanning at low elevation angles, and the knowledge of the exact amount of signal loss through beam blockage becomes necessary. The phase shift between the radar signals at horizontal and vertical polarizations is affected by the hydrometeors that the beam travels through, but remains unaffected by variations in signal strength. This has allowed for several ways of compensating for the attenuation of the signal, and for consistency checks between these variables. In this study, we make use of several weather radars and gauge network measuring in the same area to examine the effectiveness of several methods of attenuation and beam blockage corrections. The methods include consistency checks of radar reflectivity and specific differential phase, calculation of beam blockage using a topography map, estimating attenuation using differential propagation phase, and the ZPHI method proposed by Testud et al. in 2000. Results show the high effectiveness of differential phase in estimating attenuation, and potential of the ZPHI method to compensate attenuation, beam blockage, and calibration errors.

External Beam Radiation Therapy for Cancer

Science.gov (United States)

External beam radiation therapy is used to treat many types of cancer. it is a local treatment, where a machine aims radiation at your cancer. Learn more about different types of external beam radiation therapy, and what to expect if you're receiving treatment.

Use of primary beam filtration in estimating mass attenuation coefficients by Compton scattering

International Nuclear Information System (INIS)

O'Connor, B.H.; Chang, W.J.

1985-01-01

Mass attenuation coefficients (MACs) are frequently estimated over a range of wavelengths in x-ray spectrometry from the intensity of the Compton peak I /SUB C/ associated with a prominent tube line. The MAC μ /SUB ll/ at wavelength lambda is estimated from the MAC at the Compton wavelength lambda /SUB C/ with the approximations μ /SUB ll/ α μ /SUB C/ and μ /SUB C/ α l/I /SUB C/ , Systematic errors may introduce absorption edge bias (AEB) effects into the results, caused by sample components with absorption edges between lambda /SUB C/ and lambda. A procedure is described which eliminates AEB effects by measuring I /SUB C/ using emission radiation from a primary beam filter

Characteristics of liver tissue for attenuate the gamma radiation

International Nuclear Information System (INIS)

Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R.

2005-01-01

It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of 137 Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10 -3 to 10 -5 MeV and the measured coefficient was compared with the one calculated. (Author)

Exact Reconstruction From Uniformly Attenuated Helical Cone-Beam Projections in SPECT

International Nuclear Information System (INIS)

Gullberg, Grant T.; Huang, Qiu; You, Jiangsheng; Zeng, Gengsheng L.

2008-01-01

In recent years the development of cone-beam reconstruction algorithms has been an active research area in x-ray computed tomography (CT), and significant progress has been made in the advancement of algorithms. Theoretically exact and computationally efficient analytical algorithms can be found in the literature. However, in single photon emission computed tomography (SPECT), published cone-beam reconstruction algorithms are either approximate or involve iterative methods. The SPECT reconstruction problem is more complicated due to degradations in the imaging detection process, one of which is the effect of attenuation of gamma ray photons. Attenuation should be compensated for to obtain quantitative results. In this paper, an analytical reconstruction algorithm for uniformly attenuated cone-beam projection data is presented for SPECT imaging. The algorithm adopts the DBH method, a procedure consisting of differentiation and backprojection followed by a finite inverse cosh-weighted Hilbert transform. The significance of the proposed approach is that a selected region of interest can be reconstructed even with a detector with a reduced field of view. The algorithm is designed for a general trajectory. However, to validate the algorithm, a numerical study was performed using a helical trajectory. The implementation is efficient and the simulation result is promising

Radiation collimator for use with high energy radiation beams

International Nuclear Information System (INIS)

Malak, S.P.

1978-01-01

A collimator is described for use with a beam of radiation, and in particular, for use in controlling the cross-sectional size and shape of the radiation beam and intercepting undesired off-focus radiation in an x-ray apparatus. The collimator is positioned adjacent to the source of radiation and embodies a plurality longitudinally extending leaves pivotally mounted on and between two supports, the leaves move about their pivots to close overlapping relation to define a hollow cone. The cone defines an aperture at its narrow end which can be adjusted in size and shape by rotation of the two supports which are adaptable to being moved one relative to the other, to cause an expansion or contraction of the hollow cone and correspondingly an increase or decrease of the cross-sectional size and/or shape of the radiation beam passing through the aperture

Effect of beam-attenuation modulation on fluctuation measurements by heavy-ion beam probe

International Nuclear Information System (INIS)

Ross, D.W.; Sloan, M.L.; Wootton, A.J.

1991-03-01

Beam-attenuation modulation arising from density fluctuations along the orbit of the heavy-ion beam probe can distort the local amplitude, coherence, and phase derived from one- and two-point correlation measurements. Path-integral expressions for these effects are derived and applications to TEXT data are discussed. The effects depend critically on the ratio of the average fluctuation amplitude, n e , along the beam path to the local n e at the sample volume. Because the fluctuation amplitude is small in the core and rises sharply toward the plasma edge, the contamination effect is negligible in a radial zone near the edge but rises sharply to the interior of a critical radius. With increasing average plasma density, bar n e , the interior contamination increases strongly and the critical radius moves outward. 16 refs., 12 figs

Attenuative effects of G-CSF in radiation induced intestinal injury

International Nuclear Information System (INIS)

Kim, Joong Sun; Gong, Eun Ji; Kim, Sung Dae; Heo, Kyu; Ryoo, Seung Bum; Yang, Kwang Mo

2011-01-01

Granulocyte colony stimulating factor (G-CSF) has been reported to protect from radiationinduced myelosuppression. Growing evidence suggests that G-CSF also has many important non-hematopoietic functions in other tissues, including the intestine (Kim et al., 2010; Kim et al., 2011). However, little is known about the influence of G-CSF on intestinal injury. Examination 12 hours after radiation (5 Gy) revealed that the G-CSF treated mice were significantly protected from apoptosis of jejunal crypt, compared with radiation controls. G-CSF treatment attenuated intestinal morphological changes such as decreased survival crypt, the number of villi, villous shortening, crypt depth and length of basal lamina of 10 enterocytes compared with the radiation control 3.5 days after radiation (10 Gy). G-CSF attenuated the change of peripheral blood from radiation-induced myelosuppression and displayed attenuation of mortality in lethally-irradiated (10 Gy) mice. The present results support the suggestion that G-CSF administrated prior to radiation plays an important role in the survival of irradiated mice, possibly due to the protection of hematopoietic cells and intestinal stem cells against radiation. The results indicate that G-CSF protects from radiation-mediated intestinal damage and from hematopoietic injury. G-CSF treatment may be useful clinically in the prevention of injury following radiation.

Evaluation of dose attenuation factor of armored car against radiation accidents

International Nuclear Information System (INIS)

Sato, Tatsuhiko; Fujii, Katsutoshi; Murayama, Takashi

2002-03-01

The Tokyo Fire Department developed an armored car against radiation accidents. The car is covered by lead shields for attenuating dose from gamma rays. Dose from neutrons also can be attenuated by pouring water into tanks attached to the surface of the car. However, dose attenuation factors of the radiation shields had been determined by an estimation of single-layer shield, and more precise evaluation of multi-layer shield was required. By request from the Tokyo Fire Department, a precise evaluation of the dose attenuation in multi-layer shield was carried out. The evaluation was made by a Monte Carlo radiation transport simulation code MCNP4B for the shields used in the front, side and back of the car. Three types of the radiation sources ( 252 Cf as a neutron source, 60 Co as a gamma ray source, and radiation source corresponding to the JCO criticality accident) were considered in the calculation. Benchmark experiments using neutron and gamma ray sources were also performed for ensuring the evaluation method. As a result, it was found out that doses of neutron and gamma ray were attenuated to approximately 10% and 25% by the thickest shield, respectively. These values were close to the ones which had already obtained by the estimation of single-layer shield. (author)

An experimental attenuation plate to improve the dose distribution in intraoperative electron beam radiotherapy for breast cancer.

Science.gov (United States)

Oshima, T; Aoyama, Y; Shimozato, T; Sawaki, M; Imai, T; Ito, Y; Obata, Y; Tabushi, K

2009-06-07

Intraoperative electron beam radiotherapy (IOERT) is a technique in which a single-fraction high dose is intraoperatively delivered to subclinical tumour cells using an electron beam after breast-conserving surgery. In IOERT, an attenuation plate consisting of a pair of metal disks is commonly used to protect the normal tissues posterior to the breast. However, the dose in front of the plate is affected by backscatter, resulting in an unpredictable delivered dose to the tumour cells. In this study, an experimental attenuation plate, termed a shielding plate, was designed using Monte Carlo simulation, which significantly diminished the electron beam without introducing any backscatter radiation. The plate's performance was verified by measurements. It was made of two layers, a first layer (source side) of polymethyl methacrylate (PMMA) and a second layer of copper, which was selected from among other metals (aluminium, copper and lead) after testing for shielding capability and the range and magnitude of backscatter. The optimal thicknesses of the PMMA (0.71 cm) and copper (0.3 cm) layers were determined by changing their thicknesses during simulations. On the basis of these results, a shielding plate was prototyped and depth doses with and without the plate were measured by radiophotoluminescence glass dosimeters using a conventional stationary linear accelerator and a mobile linear accelerator dedicated for IOERT. The trial shielding plate functioned as intended, indicating its applicability in clinical practice.

Radiation Attenuation and Stability of ClearView Radiation Shielding TM-A Transparent Liquid High Radiation Shield.

Science.gov (United States)

Bakshi, Jayeesh

2018-04-01

Radiation exposure is a limiting factor to work in sensitive environments seen in nuclear power and test reactors, medical isotope production facilities, spent fuel handling, etc. The established choice for high radiation shielding is lead (Pb), which is toxic, heavy, and abidance by RoHS. Concrete, leaded (Pb) bricks are used as construction materials in nuclear facilities, vaults, and hot cells for radioisotope production. Existing transparent shielding such as leaded glass provides minimal shielding attenuation in radiotherapy procedures, which in some cases is not sufficient. To make working in radioactive environments more practicable while resolving the lead (Pb) issue, a transparent, lightweight, liquid, and lead-free high radiation shield-ClearView Radiation Shielding-(Radium Incorporated, 463 Dinwiddie Ave, Waynesboro, VA). was developed. This paper presents the motivation for developing ClearView, characterization of certain aspects of its use and performance, and its specific attenuation testing. Gamma attenuation testing was done using a 1.11 × 10 Bq Co source and ANSI/HPS-N 13.11 standard. Transparency with increasing thickness, time stability of liquid state, measurements of physical properties, and performance in freezing temperatures are reported. This paper also presents a comparison of ClearView with existing radiation shields. Excerpts from LaSalle nuclear power plant are included, giving additional validation. Results demonstrated and strengthened the expected performance of ClearView as a radiation shield. Due to the proprietary nature of the work, some information is withheld.

A NOVEL, REMOVABLE, CERROBEND, BEAM-BLOCKING DEVICE FOR RADIATION THERAPY OF THE CANINE HEAD AND NECK: PILOT STUDY.

Science.gov (United States)

Kent, Michael S; Berlato, Davide; Vanhaezebrouck, Isabelle; Gordon, Ira K; Hansen, Katherine S; Theon, Alain P; Holt, Randall W; Trestrail, Earl A

2017-01-01

Radiation therapy of the head and neck can result in mucositis and other acute affects in the oral cavity. This prospective pilot study evaluated a novel, intraoral, beam-blocking device for use during imaging and therapeutic procedures. The beam-blocking device was made from a metal alloy inserted into a coated frozen dessert mold (Popsicle® Mold, Cost Plus World Market, Oakland, CA). The device was designed so that it could be inserted into an outer shell, which in turn allowed it to be placed or removed depending on the need due to beam configuration. A Farmer type ionization chamber and virtual water phantom were used to assess effects of field size on transmission. Six large breed cadaver dogs, donated by the owner after death, were recruited for the study. Delivered dose at the dorsal and ventral surfaces of the device, with and without the alloy block in place, were measured using radiochromic film. It was determined that transmission was field size dependent with larger field sizes leading to decreased attenuation of the beam, likely secondary to scatter. The mean and median transmission on the ventral surface without the beam-blocking device was 0.94 [range 0.94-0.96]. The mean and median transmission with the beam-blocking device was 0.52 [range 0.50-0.57]. The mean and median increase in dose due to backscatter on the dorsal surface of the beam-blocking device was 0.04 [range 0.02-0.04]. Findings indicated that this novel device can help attenuate radiation dose ventral to the block in dogs, with minimal backscatter. © 2016 American College of Veterinary Radiology.

Radiation attenuation gauge with magnetically coupled source

International Nuclear Information System (INIS)

Wallace, S.A.

1978-01-01

Disclosed is a radiation attenuation gauge for measuring thickness and density of a material which includes, in combination, a source of gamma radiation contained within a housing of magnetic or ferromagnetic material, and a means for measuring the intensity of gamma radiation. The measuring means has an aperture and magnetic means disposed adjacent to the aperture for attracting and holding the housed source in position before the aperture. The material to be measured is placed between the source and the measuring means

Estuarine morphometry governs optically active substances, Kd(PAR) and beam attenuation

DEFF Research Database (Denmark)

Lund-Hansen, L. C.; Nielsen, J. M.; Blüthgen, J.

2013-01-01

estuaries using OACs as input parameters. It is concluded that there are no large differences in OAC concentrations between the two estuaries. The spatial distributions of OACs and optical properties were significantly different and governed by the estuary morphometry, i.e. a power distribution......°N) at high discharges. The major difference was the spatial distribution of the optical properties against distance, best described by significant power functions in the ria, compared to significant linear functions in the coastal plain. It was hypothesized that estuarine morphometry could explain...... this spatial distribution. Partition and multiple regression analyses showed that Chl-a governed Kd(PAR) and beam attenuation coefficient in both estuaries. Significant, high correlations were obtained by multiple regression analyses in the estimation of Kd(PAR) and beam attenuation coefficients in the two...

Acoustic radiation force on a double-layer microsphere by a Gaussian focused beam

International Nuclear Information System (INIS)

Wu, Rongrong; Cheng, Kaixuan; Liu, Jiehui; Mao, Yiwei; Gong, Xiufen; Liu, Xiaozhou

2014-01-01

A new model for calculating the radiation force on double-layer microsphere is proposed based on the ray acoustics approach. The axial acoustic radiation force resulting from a focused Gaussian beam incident on spherical shells immersed in water is examined theoretically in relation to its thickness and the contents of its double-layer. The attenuation both in the water and inside the sphere is considered in this method, which cannot be ignored while the high frequency ultrasonic is used. Results of numerical calculations are presented for fat and low density polyethylene materials, with the hollow region filled with animal oil, water, or air. These results show how the acoustic impedance and the sound velocity of both layers, together with the thickness of the shell, affect the acoustic radiation force.

A beam radiation monitoring and protection system for AGS secondary beams

International Nuclear Information System (INIS)

Levine, G.S.

1978-01-01

A commercially available radiation monitor using a scintillation detector was modified for charged particle beam monitoring. The device controls access to secondary beams of the AGS and limits beam intensity

Radiation-induced attenuation in integrated optical materials

International Nuclear Information System (INIS)

Evans, B.D.

1989-01-01

This paper reports that three materials commonly employed in opto-electronic integrated circuits evaluated for radiation-induced optical attenuation in the range 300 nm to 3000 nm. These include optically clear epoxy and crystalline lithium niobate after Co-60 exposure and crystalline tellurium dioxide after mixed gamma/fast-neutron exposure. In all these materials, however, induced loss was restricted to shorter wavelengths; attenuation induced at the telecommunications windows near 850, 1300 and 1550 nm was <0.1 dB/cm

Attenuation of laser power of a focused Gaussian beam during interaction between a laser and powder in coaxial laser cladding

International Nuclear Information System (INIS)

Liu Jichang; Li Lijun; Zhang Yuanzhong; Xie Xiaozhu

2005-01-01

The power of a focused laser beam with a Gaussian intensity profile attenuated by powder in coaxial laser cladding is investigated experimentally and theoretically, and its resolution model is developed. With some assumptions, it is concluded that the attenuation of laser power is an exponential function and is determined by the powder feed rate, particle moving speed, spraying angles and waist positions and diameters of the laser beam and powder flow, grain diameter and run of the laser beam through the powder flow. The attenuation of laser power increases with powder feed rate or run of laser beam through the powder flow. In the experiment presented, 300 W laser power from a focused Gaussian beam is attenuated by a coaxial powder flow. The experimental results agree well with the values calculated with the developed model

Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses [Shielding Synchrotron Light Sources: Importance of geometry for calculating radiation levels from beam losses

International Nuclear Information System (INIS)

Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

2016-01-01

Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (<10 MeV), which will spread the incident energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. Lastly, the principles used to provide

Modeling and control of sound radiation by simply supported and cantilever beam coupled with smart material

Directory of Open Access Journals (Sweden)

Vitaly Makarenko

2007-03-01

Full Text Available  In this paper forced vibration of the beam due to bonded piezoelectric patch is considered. When an external excitation is applied to the beam, it starts to vibrate, and the resulting acoustic response is predicted from the analytical model, which is based on Bernoulli-Euler theory of beam vibration. Analytical research of the sound radiation by a finite elastic beam is done for criteria based on minimal total sound power level. Helmholtz equation and inhomogeneous differential equation for beam transverse motion defines the solution to this problem. Such solutions were found for boundary conditions of simply supported and cantilever beams. In order to solve the task two analytical methods were used for simply supported beam. The solutions received by Fourier transform and Green functions approach give the very similar results, thus, proving methods reliability. At the case studies the exerted voltage, phase, location and piezoelectric actuator length are varied in order to establish their influence on noise attenuation.

An Analytical-empirical Calculation of Linear Attenuation Coefficient of Megavoltage Photon Beams.

Science.gov (United States)

Seif, F; Tahmasebi-Birgani, M J; Bayatiani, M R

2017-09-01

In this study, a method for linear attenuation coefficient calculation was introduced. Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury. The values of calculated linear attenuation coefficient with this new method are in acceptable range. Also, the linear attenuation coefficient decreases slightly as the thickness of attenuating filter (Cerrobend or mercury) increased, so the procedure of linear attenuation coefficient variation is in agreement with other documents. The results showed that the attenuation ability of mercury was about 1.44 times more than Cerrobend. The method that was introduced in this study for linear attenuation coefficient calculation is general enough to treat beam modifiers with any shape or material by using the same formalism; however, calculating was made only for mercury and Cerrobend attenuator. On the other hand, it seems that this method is suitable for high energy shields or protector designing.

Transition radiation electron beam diagnostic study at ATF

International Nuclear Information System (INIS)

Qiu, X.Z.; Wang, X.J.; Batchelor, K.; Ben-Zvi, I.

1995-01-01

Recently we have started a program to develop transition radiation based electron beam diagnostics at the Accelerator Test Facility at Brookhaven National Laboratory. In this paper, we will discuss a technique to estimate the lower limit in electron beam divergence measurement with single foil transition radiation and two-foil transition radiation interferometer. Preliminary experimental data from 4.5 MeV electron beam will be presented

Radiative cooling of relativistic electron beams

International Nuclear Information System (INIS)

Huang, Z.

1998-05-01

Modern high-energy particle accelerators and synchrotron light sources demand smaller and smaller beam emittances in order to achieve higher luminosity or better brightness. For light particles such as electrons and positrons, radiation damping is a natural and effective way to obtain low emittance beams. However, the quantum aspect of radiation introduces random noise into the damped beams, yielding equilibrium emittances which depend upon the design of a specific machine. In this dissertation, the author attempts to make a complete analysis of the process of radiation damping and quantum excitation in various accelerator systems, such as bending magnets, focusing channels and laser fields. Because radiation is formed over a finite time and emitted in quanta of discrete energies, he invokes the quantum mechanical approach whenever the quasiclassical picture of radiation is insufficient. He shows that radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg uncertainty principle. In addition, he investigates methods of rapid damping such as radiative laser cooling. He proposes a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to rapid cooling of electron beams and can be used to overcome the space charge effects encountered in a medium energy circular machine. Applications to the designs of low emittance damping rings and compact x-ray sources are also explored

Radiative cooling of relativistic electron beams

Energy Technology Data Exchange (ETDEWEB)

Huang, Zhirong [Stanford Univ., CA (United States)

1998-05-01

Modern high-energy particle accelerators and synchrotron light sources demand smaller and smaller beam emittances in order to achieve higher luminosity or better brightness. For light particles such as electrons and positrons, radiation damping is a natural and effective way to obtain low emittance beams. However, the quantum aspect of radiation introduces random noise into the damped beams, yielding equilibrium emittances which depend upon the design of a specific machine. In this dissertation, the author attempts to make a complete analysis of the process of radiation damping and quantum excitation in various accelerator systems, such as bending magnets, focusing channels and laser fields. Because radiation is formed over a finite time and emitted in quanta of discrete energies, he invokes the quantum mechanical approach whenever the quasiclassical picture of radiation is insufficient. He shows that radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg uncertainty principle. In addition, he investigates methods of rapid damping such as radiative laser cooling. He proposes a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to rapid cooling of electron beams and can be used to overcome the space charge effects encountered in a medium energy circular machine. Applications to the designs of low emittance damping rings and compact x-ray sources are also explored.

Radiation effects of ion beams on polymers

International Nuclear Information System (INIS)

Tagawa, Seiichi

1993-01-01

Recent progress in the radiation effects of ion beams on polymers are reviewed briefly. Our recent work on the radiation effects of ion beams on polystyrene thin films on silicon wafers and time resolved emission studies on polymers are described. (orig.)

Photon mass attenuation coefficients of a silicon resin loaded with WO3, PbO, and Bi2O3 Micro and Nano-particles for radiation shielding

Science.gov (United States)

Verdipoor, Khatibeh; Alemi, Abdolali; Mesbahi, Asghar

2018-06-01

Novel shielding materials for photons based on silicon resin and WO3, PbO, and Bi2O3 Micro and Nano-particles were designed and their mass attenuation coefficients were calculated using Monte Carlo (MC) method. Using lattice cards in MCNPX code, micro and nanoparticles with sizes of 100 nm and 1 μm was designed inside a silicon resin matrix. Narrow beam geometry was simulated to calculate the attenuation coefficients of samples against mono-energetic beams of Co60 (1.17 and 1.33 MeV), Cs137 (663.8 KeV), and Ba133 (355.9 KeV). The shielding samples made of nanoparticles had higher mass attenuation coefficients, up to 17% relative to those made of microparticles. The superiority of nano-shields relative to micro-shields was dependent on the filler concentration and the energy of photons. PbO, and Bi2O3 nanoparticles showed higher attenuation compared to WO3 nanoparticles in studied energies. Fabrication of novel shielding materials using PbO, and Bi2O3 nanoparticles is recommended for application in radiation protection against photon beams.

Beam-limiting and radiation-limiting interlocks

International Nuclear Information System (INIS)

Macek, R.J.

1996-01-01

This paper reviews several aspects of beam-limiting and radiation- limiting interlocks used for personnel protection at high-intensity accelerators. It is based heavily on the experience at the Los Alamos Neutron Science Center (LANSCE) where instrumentation-based protection is used extensively. Topics include the need for ''active'' protection systems, system requirements, design criteria, and means of achieving and assessing acceptable reliability. The experience with several specific devices (ion chamber-based beam loss interlock, beam current limiter interlock, and neutron radiation interlock) designed and/or deployed to these requirements and criteria is evaluated

Attenuation of VHE Gamma Rays by the Milky Way Interstellar Radiation Field

Energy Technology Data Exchange (ETDEWEB)

Moskalenko, Igor V.; /Stanford U., HEPL; Porter, Troy A.; /Louisiana State U.; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

2006-04-19

The attenuation of very high energy gamma rays by pair production on the Galactic interstellar radiation field has long been thought of as negligible. However, a new calculation of the interstellar radiation field consistent with multi-wavelength observations by DIRBE and FIRAS indicates that the energy density of the Galactic interstellar radiation field is higher, particularly in the Galactic center, than previously thought. We have made a calculation of the attenuation of very high energy gamma rays in the Galaxy using this new interstellar radiation field which takes into account its nonuniform spatial and angular distributions. We find that the maximum attenuation occurs around 100 TeV at the level of about 25% for sources located at the Galactic center, and is important for both Galactic and extragalactic sources.

Scattered radiation from applicators in clinical electron beams

International Nuclear Information System (INIS)

Battum, L J van; Zee, W van der; Huizenga, H

2003-01-01

In radiotherapy with high-energy (4-25 MeV) electron beams, scattered radiation from the electron applicator influences the dose distribution in the patient. In most currently available treatment planning systems for radiotherapy this component is not explicitly included and handled only by a slight change of the intensity of the primary beam. The scattered radiation from an applicator changes with the field size and distance from the applicator. The amount of scattered radiation is dependent on the applicator design and on the formation of the electron beam in the treatment head. Electron applicators currently applied in most treatment machines are essentially a set of diaphragms, but still do produce scattered radiation. This paper investigates the present level of scattered dose from electron applicators, and as such provides an extensive set of measured data. The data provided could for instance serve as example input data or benchmark data for advanced treatment planning algorithms which employ a parametrized initial phase space to characterize the clinical electron beam. Central axis depth dose curves of the electron beams have been measured with and without applicators in place, for various applicator sizes and energies, for a Siemens Primus, a Varian 2300 C/D and an Elekta SLi accelerator. Scattered radiation generated by the applicator has been found by subtraction of the central axis depth dose curves, obtained with and without applicator. Scattered radiation from Siemens, Varian and Elekta electron applicators is still significant and cannot be neglected in advanced treatment planning. Scattered radiation at the surface of a water phantom can be as high as 12%. Scattered radiation decreases almost linearly with depth. Scattered radiation from Varian applicators shows clear dependence on beam energy. The Elekta applicators produce less scattered radiation than those of Varian and Siemens, but feature a higher effective angular variance. The scattered

WE-D-210-04: Radiation-Induced Polymerization of Ultrasound Contrast Agents in View of Non-Invasive Dosimetry in External Beam Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Callens, M; Verboven, E; Van Den Abeele, K [Department of Physics, Wave Propagation and Signal Processing, KU Leuven KULAK, Kortrijk (Belgium); D’Agostino, E [DoseVue NV, Hasselt (Belgium); Pfeiffer, H [Department of Materials Engineering, KU Leuven, Leuven (Belgium); D’hooge, J [Department of Cardiovascular Sciences, Bio-Medical Science Group, KU Leuven, Leuven (Belgium)

2015-06-15

Purpose: Ultrasound contrast agents (UCA’s) based on gas-filled microbubbles encapsulated by an amphiphilic shell are well established as safe and effective echo-enhancers in diagnostic imaging. In view of an alternative application of UCA’s, we investigated the use of targeted microbubbles as radiation sensors for external beam radiation therapy. As radiation induces permanent changes in the microbubble’s physico-chemical properties, a robust measure of these changes can provide a direct or indirect estimate of the applied radiation dose. For instance, by analyzing the ultrasonic dispersion characteristics of microbubble distributions before and after radiation treatment, an estimate of the radiation dose at the location of the irradiated volume can be made. To increase the radiation sensitivity of microbubbles, polymerizable diacetylene molecules can be incorporated into the shell. This study focuses on characterizing the acoustic response and quantifying the chemical modifications as a function of radiation dose. Methods: Lipid/diacetylene microbubbles were irradiated with a 6 MV photon beam using dose levels in the range of 0–150 Gy. The acoustic response of the microbubbles was monitored by ultrasonic through-transmission measurements in the range of 500 kHz to 20 MHz, thereby providing the dispersion relations of the phase velocity, attenuation and nonlinear coefficient. In addition, the radiation-induced chemical modifications were quantified using UV-VIS spectroscopy. Results: UV-VIS spectroscopy measurements indicate that ionizing radiation induces the polymerization of diacetylenes incorporated in the microbubble shell. The polymer yield strongly depends on the shell composition and the radiation-dose. The acoustic response is inherently related to the visco-elastic properties of the shell and is strongly influenced by the shell composition and the physico-chemical changes in the environment. Conclusion: Diacetylene-containing microbubbles are

Anomalous x-ray radiation of beam plasma

International Nuclear Information System (INIS)

Dimitrov, S.K.; Zavyalov, M.A.; Mikhin, S.G.; Tarasenkov, V.A.; Telkovskij, V.G.; Khrabrov, V.A.

1985-01-01

The properties of non-equilibrium stationary plasma under the conditions of the planned plasma-chemical reactors based on beam-plasma discharge were investigated. The x-ray spectrum of the beam-plasma was measured and anomalous spectral properties were analyzed. Starting with some critical pressure the anomalous radiation was added to the classical bremsstrahlung spectrum. The occurrence of anomalous radiation can be used to diagnose the condition of beam transportation in such systems. (D.Gy.)

Shielding data for hadron-therapy ion accelerators: Attenuation of secondary radiation in concrete

CERN Document Server

Agosteo, S; Sagia, E; Silari, M

2014-01-01

The secondary radiation field produced by seven different ion species (from hydrogen to nitrogen), impinging onto thick targets made of either iron or ICRU tissue, was simulated with the FLUKA Monte Carlo code, and transported through thick concrete shields: the ambient dose equivalent was estimated and shielding parameters evaluated. The energy for each ion beam was set in order to reach a maximum penetration in ICRU tissue of 290 mm (equivalent to the therapeutic range of 430 MeV/amu carbon ions). Source terms and attenuation lengths are given as a function of emission angle and ion species, along with fits to the Monte Carlo data, for shallow depth and deep penetration in the shield. Trends of source terms and attenuation lengths as a function of neutron emission angle and ion species impinging on tar- get are discussed. A comparison of double differential distributions of neutrons with results from similar simulation works reported in the literature is also included. The aim of this work is to provide shi...

Effect of Different Concrete Grade on Radiation Linear Attenuation Coefficient (μ)

International Nuclear Information System (INIS)

Noor Azreen Masenwat; Mohammad Shahrizan Samsu; Mohamad Pauzi Ismail; Suhairy Sani; Ismail Mustapha; Nasharuddin Isa; Mohamad Haniza Mahmud

2014-01-01

In calculating the quantity of absorption of radiation and its relationship with the thickness of a material, linear attenuation coefficient (μ) of the material is one of the parameters to be taken into account. For normal concrete, the (μ) varies depending on the type of radiation used, 0.105 cm -1 for Co-60 and 0.123 cm -1 for Cs-137. Value (μ) is used in the calculation of the radiation absorption for concrete material does not take into account factors such concrete grades. In this research, concrete with different grades (Grade 15, Grade 20, Grade 25, Grade 30, Grade 35, Grade 40) are designed and manufactured with reference to the mixing method described in British Standard. Then, the linear attenuation (μ) for each grade are measured using the radiation from the source Co-60 and Cs-137 sources. This paper describes and discusses the impact of differences in concrete grade of linear attenuation (μ) for Co-60 source/ source Cs-137 and its relationship with the compressive strength. (author)

Beam diagnostics using transition radiation produced by a 100 Mev electron beam

International Nuclear Information System (INIS)

Jablonka, M.; Leroy, J.; Hanus, X.; Derost, J.C.; Wartski, L.

1991-01-01

We report on several experiments using the optical transition radiation (OTR) produced by a 100 MeV electron beam. In using a sensitive video camera coupled with a digital image processing system an accurate and simple beam profile monitor has been devised. In measuring with a photo-multiplier the radiation emitted in a small solid angle around the direction of the OTR emission, a signal very sensitive to beam energy variations has been obtained. These experiments have been carried out on the Saclay ALS linac

Emission of electromagnetic radiation from beam driven plasmas

International Nuclear Information System (INIS)

Newman, D.L.

1985-01-01

Two production mechanisms for electromagnetic radiation from a plasma containing electron-beam-driven weak Langmuir turbulence are studied: induced Compton conversion and two-Langmuir-wave coalescence. Induced Compton conversion in which a Langmuir wave scatters off a relativistic electron while converting into a transversely polarized electromagnetic wave is considered as a means for producing amplified electromagnetic radiation from a beam-plasma system at frequencies well above the electron plasma frequency. The induced emission growth rates of the radiation produced by a monoenergetic ultrarelativistic electron beam are determined as a function of the Langmuir turbulence spectrum in the background plasma and are numerically evaluated for a range of model Langmuir spectra. Induced Compton conversion can play a role in emission from astrophysical beam-plasma systems if the electron beam is highly relativistic and sufficiently narrow. However, it is found that the growth rates for this process are too small in all cases studied to account for the intense high-frequency radiation observed in laboratory experiments. Two-Langmuir-wave coalescence as a means of producing radiation at 2omega/sub p/ is investigated in the setting of the earth's foreshock

Radiation and shielding around beam absorbers

International Nuclear Information System (INIS)

Hurkmans, A.; Maas, R.

1978-12-01

During operational conditions it is anticipated that a fair amount of the total available beam power is dumped in either the slit system on one of the beam dumps. Thses beam absorbers therefore become strong radioactive sources. The radiation level due to the absorption of a 100 kW electron beam is estimated and the problem of residual activity is treated. Proposed shielding materials are discussed. (C.F.)

Foundations of radiation physics and radiation protection. 5. ed.

International Nuclear Information System (INIS)

Krieger, Hanno

2017-01-01

The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

Effect of particulate aggregation in aquatic environments on the beam attenuation and its utility as a proxy for particulate mass.

Science.gov (United States)

Boss, Emmanuel; Slade, Wayne; Hill, Paul

2009-05-25

Marine aggregates, agglomerations of particles and dissolved materials, are an important particulate pool in aquatic environments, but their optical properties are not well understood. To improve understanding of the optical properties of aggregates, two related studies are presented. In the first, an in situ manipulation experiment is described, in which beam attenuation of undisturbed and sheared suspensions are compared. Results show that in the sheared treatment bulk particle size decreases and beam attenuation increases, consistent with the hypothesis that a significant fraction of mass in suspension is contained in fragile aggregates. Interestingly, the magnitude of increase in beam attenuation is less than expected if the aggregates are modeled as solid spheres. Motivated by this result, a second study is presented, in which marine aggregates are modeled to assess how the beam attenuation of aggregates differs from that of their constituent particles and from solid particles of the same mass. The model used is based on that of Latimer [Appl. Opt. 24, 3231 (1985)] and mass specific attenuation is compared with that based on homogeneous and solid particles, the standard model for aquatic particles. In the modeling we use recent research relating size and solid fraction of aquatic aggregates. In contrast with Mie theory, this model provides a rather size-insensitive mass specific attenuation for most relevant sizes. This insensitivity is consistent with the observations that mass specific beam-attenuation of marine particles is in the range 0.2-0.6m(2)/gr despite large variability in size distribution and composition across varied aquatic environments.

Attenuated UV Radiation Alters Volatile Profile in Cabernet Sauvignon Grapes under Field Conditions.

Science.gov (United States)

Liu, Di; Gao, Yuan; Li, Xiao-Xi; Li, Zheng; Pan, Qiu-Hong

2015-09-17

This study aimed to explore the effect of attenuated UV radiation around grape clusters on the volatile profile of Cabernet Sauvignon grapes (Vitis vinifera L. cv.) under field conditions. Grape bunches were wrapped with two types of polyester films that cut off 89% (film A) and 99% (film B) invisible sunlight of less than 380 nm wavelength, respectively. Solar UV radiation reaching the grape berry surface was largely attenuated, and an increase in the concentrations of amino acid-derived benzenoid volatiles and fatty acid-derived esters was observed in the ripening grapes. Meanwhile, the attenuated UV radiation significantly reduced the concentrations of fatty acid-derived aldehydes and alcohols and isoprenoid-derived norisoprenoids. No significant impact was observed for terpenes. In most case, these positive or negative effects were stage-dependent. Reducing UV radiation from the onset of veraison to grape harvest, compared to the other stages, caused a larger alteration in the grape volatile profile. Partial Least Square Discriminant Analysis (PLS-DA) revealed that (E)-2-hexenal, 4-methyl benzaldehyde, 2-butoxyethyl acetate, (E)-2-heptenal, styrene, α-phenylethanol, and (Z)-3-hexen-1-ol acetate were affected most significantly by the attenuated UV radiation.

Attenuated UV Radiation Alters Volatile Profile in Cabernet Sauvignon Grapes under Field Conditions

Directory of Open Access Journals (Sweden)

Di Liu

2015-09-01

Full Text Available This study aimed to explore the effect of attenuated UV radiation around grape clusters on the volatile profile of Cabernet Sauvignon grapes (Vitis vinifera L. cv. under field conditions. Grape bunches were wrapped with two types of polyester films that cut off 89% (film A and 99% (film B invisible sunlight of less than 380 nm wavelength, respectively. Solar UV radiation reaching the grape berry surface was largely attenuated, and an increase in the concentrations of amino acid-derived benzenoid volatiles and fatty acid-derived esters was observed in the ripening grapes. Meanwhile, the attenuated UV radiation significantly reduced the concentrations of fatty acid-derived aldehydes and alcohols and isoprenoid-derived norisoprenoids. No significant impact was observed for terpenes. In most case, these positive or negative effects were stage-dependent. Reducing UV radiation from the onset of veraison to grape harvest, compared to the other stages, caused a larger alteration in the grape volatile profile. Partial Least Square Discriminant Analysis (PLS-DA revealed that (E-2-hexenal, 4-methyl benzaldehyde, 2-butoxyethyl acetate, (E-2-heptenal, styrene, α-phenylethanol, and (Z-3-hexen-1-ol acetate were affected most significantly by the attenuated UV radiation.

Fast infrared detectors for beam diagnostics with synchrotron radiation

International Nuclear Information System (INIS)

Bocci, A.; Marcelli, A.; Pace, E.; Drago, A.; Piccinini, M.; Cestelli Guidi, M.; De Sio, A.; Sali, D.; Morini, P.; Piotrowski, J.

2007-01-01

Beam diagnostic is a fundamental constituent of any particle accelerators either dedicated to high-energy physics or to synchrotron radiation experiments. All storage rings emit radiations. Actually they are high brilliant sources of radiation: the synchrotron radiation emission covers from the infrared range to the X-ray domain with a pulsed structure depending on the temporal characteristics of the stored beam. The time structure of the emitted radiation is extremely useful as a tool to perform time-resolved experiments. However, this radiation can be also used for beam diagnostic to determine the beam stability and to measure the dimensions of the e - or e + beam. Because of the temporal structure of the synchrotron radiation to perform diagnostic, we need very fast detectors. Indeed, the detectors required for the diagnostics of the stored particle bunches at third generation synchrotron radiation sources and FEL need response times in the sub-ns and even ps range. To resolve the bunch length and detect bunch instabilities, X-ray and visible photon detectors may be used achieving response times of a few picoseconds. Recently, photon uncooled infrared devices optimized for the mid-IR range realized with HgCdTe semiconductors allowed to obtain sub-nanosecond response times. These devices can be used for fast detection of intense IRSR sources and for beam diagnostic. We present here preliminary experimental data of the pulsed synchrotron radiation emission of DAΦNE, the electron positron collider of the LNF laboratory of the INFN, performed with new uncooled IR detectors with a time resolution of a few hundreds of picoseconds

Attenuation characteristics of materials used in radiation protection as radiation shielding

International Nuclear Information System (INIS)

Almeida Junior, Airton T.; Araujo, F.G.S.; Nogueira, M.S.; Santos, M.A.P.

2013-01-01

Crystal glass has been widely used as shielding material in gamma radiation sources as well as x-ray generating equipment to replace the plumbiferous glass, in order to minimize exposure to individuals. In this work, ten plates of crystal glass, with dimensions of 20cm x 20cm and range of thicknesses from 0.5 to 2.0 cm, and barite concrete were irradiated with potential constants of 60kV, 80kV, 110kV, 150kV and gamma radiation of 60 Co. The curves of attenuation and of transmission were obtained for crystal glass, barite plaster and barite concrete (mGy/mA.min) at 1 meter as a function of thickness.Crystal glass has been widely used as shielding material in gamma radiation sources as well as x-ray generating equipment to replace the plumbiferous glass, in order to minimize exposure to individuals. In this work, ten plates of crystal glass, with dimensions of 20cm x 20cm and range of thicknesses from 0.5 to 2.0 cm, and barite concrete were irradiated with potential constants of 60kV, 80kV, 110kV, 150kV and gamma radiation of 60 Co. The curves of attenuation and of transmission were obtained for crystal glass, barite plaster and barite concrete (mGy/mA.min) at 1 meter as a function of thickness. (author)

Spin-polarized free electron beam interaction with radiation and superradiant spin-flip radiative emission

Directory of Open Access Journals (Sweden)

A. Gover

2006-06-01

Full Text Available The problems of spin-polarized free-electron beam interaction with electromagnetic wave at electron-spin resonance conditions in a magnetic field and of superradiant spin-flip radiative emission are analyzed in the framework of a comprehensive classical model. The spontaneous emission of spin-flip radiation from electron beams is very weak. We show that the detectivity of electron spin resonant spin-flip and combined spin-flip/cyclotron-resonance-emission radiation can be substantially enhanced by operating with ultrashort spin-polarized electron beam bunches under conditions of superradiant (coherent emission. The proposed radiative spin-state modulation and the spin-flip radiative emission schemes can be used for control and noninvasive diagnostics of polarized electron/positron beams. Such schemes are of relevance in important scattering experiments off nucleons in nuclear physics and off magnetic targets in condensed matter physics.

Ultra-High Density Electron Beams for Beam Radiation and Beam Plasma Interaction

CERN Document Server

Anderson, Scott; Frigola, Pedro; Gibson, David J; Hartemann, Fred V; Jacob, Jeremy S; Lim, Jae; Musumeci, Pietro; Rosenzweig, James E; Travish, Gil; Tremaine, Aaron M

2005-01-01

Current and future applications of high brightness electron beams, which include advanced accelerators such as the plasma wake-field accelerator (PWFA) and beam-radiation interactions such as inverse-Compton scattering (ICS), require both transverse and longitudinal beam sizes on the order of tens of microns. Ultra-high density beams may be produced at moderate energy (50 MeV) by compression and subsequent strong focusing of low emittance, photoinjector sources. We describe the implementation of this method used at LLNL's PLEIADES ICS x-ray source in which the photoinjector-generated beam has been compressed to 300 fsec duration using the velocity bunching technique and focused to 20 μm rms size using an extremely high gradient, permanent magnet quadrupole (PMQ) focusing system.

Cerenkov light spectrum in an optical fiber exposed to a photon or electron radiation therapy beam

International Nuclear Information System (INIS)

Lambert, Jamil; Yin Yongbai; McKenzie, David R.; Law, Sue; Suchowerska, Natalka

2009-01-01

A Cerenkov signal is generated when energetic charged particles enter the core of an optical fiber. The Cerenkov intensity can be large enough to interfere with signals transmitted through the fiber. We determine the spectrum of the Cerenkov background signal generated in a poly(methyl methacrylate) optical fiber exposed to photon and electron therapeutic beams from a linear accelerator. This spectral measurement is relevant to discrimination of the signal from the background, as in scintillation dosimetry using optical fiber readouts. We find that the spectrum is approximated by the theoretical curve after correction for the wavelength dependent attenuation of the fiber. The spectrum does not depend significantly on the angle between the radiation beam and the axis of the fiber optic but is dependent on the depth in water at which the fiber is exposed to the beam.

Design and development of radiation absorber for sighting beam line

International Nuclear Information System (INIS)

Sridhar, R.; Shukla, S.K.

2005-01-01

During the commissioning of Indus-2 , it is necessary to view the synchrotron radiation that will be emanating from the dipole exit ports. The 10 0 beam line from dipole 11 was earmarked for sighting beam line. The synchrotron radiation power density would be around 340 watts on the photon absorber inside the radiation absorber module, at the specified beam power of Indus-2. The beam striking on this photon absorber produces x-rays and Bremsstrahlung radiation. These are to be stopped and absorbed by radiation absorber. The photon absorber and the radiation absorber are integrated in a single vacuum chamber and actuated by a pneumatic cylinder connected using a bellow. Radiation absorber was needed to isolate the diagnostic components and to protect them from radiation a well as heat when they were not in use. The paper describes the design, calculation and development of the dynamic photon cum radiation absorber. The ultimate vacuum performance is also described. (author)

Measurement of X-ray mass attenuation coefficient of nickel around the K-edge using synchrotron radiation based X-ray absorption study

International Nuclear Information System (INIS)

Roy, Bunty Rani; Rajput, Parasmani; Jha, S.N.; Nageswara Rao, A.S.

2015-01-01

The work presents the X-ray absorption fine structure (XAFS) technique for measuring the X-ray mass attenuation coefficient of nickel metal foil in the X-ray energy range of 8271.2–8849.4 eV using scanning XAFS beam line (BL-09) at Indus-2 synchrotron radiation source facility, Raja Ramanna Centre for Advanced Technology (RRCAT) at Indore, India. The result represents the X-ray mass attenuation coefficient data for 0.02 mm thick Ni metal foil in the XAFS region of Ni K-edge. However, the results are compared to theoretical values using X-COM. There is a maximum deviation which is found exactly near the K-edge jump and decreases as we move away from the absorption edge. Oscillatory structure appears just above the observed absorption edge i.e., 8348.7 eV and is confined to around 250 eV above the edge. - Highlights: • Mass attenuation coefficient measurements of nickel using synchrotron radiation. • The measurements were taken exactly near the Ni K-edge at an energy step of 1 eV. • A maximum deviation is found near the K-edge

Radiation dermatitis following electron beam therapy

International Nuclear Information System (INIS)

Price, N.M.

1978-01-01

Ten patients, who had been treated for mycosis fungoides with electron beam radiation ten or more years previously, were examined for signs of radiation dermatitis. Although most patients had had acute radiation dermatitis, only a few manifested signs of mild chronic changes after having received between 1,000 and 2,800 rads

Coherent electromagnetic radiation of a combined electron-ion beam

Energy Technology Data Exchange (ETDEWEB)

Pankratov, S G; Samoshenkov, Yu K [Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Optiko-Fizicheskikh Izmerenij, Moscow (USSR)

1977-07-01

The intensity of coherent electromagnetic radiation due to interaction of a modulated electron beam with a modulated ion beam is calculated. It is shown that the radiation intensity has a sharp maximum at the frequency equal to the difference of the modulation frequency of the electron and ion beams. The results obtained are compared with those corresponding to the scattering of a modulated electron beam on randomly distributed gas ions.

Attenuation of gamma radiation in concrete shields

International Nuclear Information System (INIS)

Azevedo e Souza, A.C. de.

1978-12-01

The attenuation characteristics of γ radiation in concrete layers considering their mechanical resistence and densities were determined. A 137 Cs source was used in a 'good geometry' arrangement to eliminate the effects of the buildup factor. The ordinary and the heavy concrete were irradiated and for the latter it was used as additives iron ore and Fe 2 O 3 pellets in various grain sizes. The detection system consisted of a 2' x 2' NaI (Tl) crystal coupled to a photomultiplier tube and the associated electronic equipment. FORTRAN programs were used for determining the absorption coefficients and the attenuation factors. These programs calculate photopeak areas eliminating all contributions due to Compton effect and background. (Author) [pt

Influence of tube voltage on CT attenuation, radiation dose, and image quality: phantom study

International Nuclear Information System (INIS)

Li Fengtan; Li Dong; Zhang Yunting

2013-01-01

Objective: To assess the influence of tube current and tube voltage on the CT attenuation, radiation dose, and image quality. Methods: A total of 113 saline solutions with decreasing dilution of contrast medium (370 mg I/ml) was produced. MDCT scan was performed with 15 series of different settings of tube current and tube voltage. CT attenuations with 15 series of different settings were all measured, and influence of tube current and tube voltage on CT attenuations was analyzed. CT dose index (CTDIvol) was recorded. The CT attenuations with different tube voltage and current were compared with one-way ANOVA and Kruskal-Wallis rank sum test. The correlation of CT attenuation with different tube voltage and the influence of tube voltage and current on radiation dose and image quality were tested by correlation analysis. Results: Tube current (250, 200, 150, 100, and 50 mA) had no significant effect on CT attenuation (F = 0.001, 0.008, 0.075, P > 0.05), while tube voltage (120, 100, and 80 kV) had significant effect (H = 17.906, 17.906, 13.527, 20.124, 23.563, P < 0.05). The correlation between CT attenuation and tube voltage was determined with equation: CT attenuatio N_1_0_0 _k_V = 1.561 × CT attenuatio N_1_2_0 _k_v + 4.0818, CT attenuatio N_8_0 _k_v = 1.2131 × CT attenuatio N_1_2_0 _k_v + 0.9283. The influence of tube voltage on radiation dose and image quality was also analyzed, and equations were also obtained: N_1_2_0 -k_v = -5.9771 Ln (D_1_2_0 kv) + 25.412, N_1_0_0 _k_v = -10.544 Ln (D_1_0_0 _k_v) + 36.262, N_8_0 _k_v = -25.326 Ln (D_8_0 _k_v) + 62.816. According to the results of relationship among CT attenuation, radiation dose, and image quality, lower tube voltage with higher tube current can reduce the radiation dose. Conclusions: Lower tube voltage can reduce the radiation dose. However, CT attenuation was influenced, and correction should be done with the equations. (authors)

Theory for beam-plasma millimeter-wave radiation source experiments

International Nuclear Information System (INIS)

Rosenberg, M.; Krall, N.A.

1989-01-01

This paper reports on theoretical studies for millimeter-wave plasma source experiments. In the device, millimeter-wave radiation is generated in a plasma-filled waveguide driven by counter-streaming electron beams. The beams excite electron plasma waves which couple to produce radiation at twice the plasma frequency. Physics topics relevant to the high electron beam current regime are discussed

Radiation therapy apparatus having retractable beam stopper

International Nuclear Information System (INIS)

Coad, G.L.

1983-01-01

This invention relates to a radiation therapy apparatus which utilized a linear translation mechanism for positioning a beam stopper. An apparatus is described wherein the beam stopper is pivotally attached to the therapy machine with an associated drive motor in such a way that the beam stopper retracts linearly

Influence of laser beam profiles on received power fluctuation

Science.gov (United States)

Dordova, Lucie; Diblik, Jan

2011-09-01

Gaussian beam is very often used for the transmission of information in optical wireless links. The usage of this optical beam has its advantages and, of course, disadvantages. This work focuses on possibilities of using laser beams with different distribution of optical intensity - Top Hat beam. Creation of the optical beam with selected optical intensity profile will be briefly described. Optical beams will propagate through the "clear" and stationary atmosphere in the experimental part of this work. These results will be compared with the data obtained after a laser beam is passed through the turbulent and attenuated atmosphere. We will use an ultrasound fog generator for laser beam attenuation testing. To create the turbulence, infra radiators will be applied. Particular results obtained from different atmospheric conditions will be compared and using different types of optical beams will be assessed.

The LCLS Gas Attenuator Revisited

International Nuclear Information System (INIS)

Ryutov, D

2005-01-01

In the report ''X-ray attenuation cell'' [1] a preliminary analysis of the gas attenuator for the Linac Coherent Light Source (LCLS) was presented. This analysis was carried out for extremely stringent set of specifications. In particular, a very large diameter for the unobstructed beam was set (1 cm) to accommodate the spontaneous radiation; the attenuator was supposed to cover the whole range of energies of the coherent radiation, from 800 eV to 8000 eV; the maximum attenuation was set at the level of 10 4 ; the use of solid attenuators was not allowed, as well as the use of rotating shutters. The need to reach a sufficient absorption at the high-energy end of the spectrum predetermined the choice of Xe as the working gas (in order to have a reasonable absorption at a not-too-high pressure). A sophisticated differential pumping system that included a Penning-type ion pump was suggested in order to minimize the gas leak into the undulator/accelerator part of the facility. A high cost of xenon meant also that an efficient (and expensive) gas-recovery system would have to be installed. The main parameter that determined the high cost and the complexity of the system was a large radius of the orifice. The present viewpoint allows for much smaller size of the orifice, r 0 = 1.5 mm. (1) The use of solid attenuators is also allowed (R.M. Bionta, private communication). It is, therefore, worthwhile to reconsider various parameters of the gas attenuator for these much less stringent conditions. This brief study should be considered as a physics input for the engineering design. As a working gas we consider now the argon, which, on the one hand, provides a reasonable absorption lengths and, on the other hand, is inexpensive enough to be exhausted into the atmosphere (no recovery). The absorption properties of argon are illustrated by Fig.1 where the attenuation factor A is shown for various beam energies, based on Ref. [2]. The other relevant parameters for argon are

Study of sugar cooking degree to sugar obtention using gamma attenuation

International Nuclear Information System (INIS)

Holanda Cavalcanti, J. de.

1984-01-01

The application of gamma radiation attenuation methodology in the determination of sugar cooking degree is studied. Several experiments with samples of vacuum equipment during the cooking were made, based on beam intensity variations of a radioactive source of Americium 241. One sensible difference between the sirup emergent radiation and the cooked mass was observed. (M.A.C.) [pt

Application of methodology for calibration of instruments utilized in dosimetry of high energy beams, for radiodiagnosis

International Nuclear Information System (INIS)

Potiens, Maria P.A.; Caldas, Linda V.E.

2000-01-01

The radiation qualities recommended by the IEC 1267 standard for the calibration of instruments used in diagnostic radiology measurements were established using a neo-diagnomax X-ray system (125 kV). The RQR radiation qualities are recommended to test ionization chambers used in non attenuated beams, and the RQA radiation qualities in attenuated beams (behind a phantom). To apply the methodology, 6 ionization chambers commonly used in diagnostic radiology were tested. The higher energy dependence (17%) was obtained for an ionization chamber recommended for mammography beams, that is not the case of the X radiation system used in this work. The other ionization chambers presented good performance in terms of energy (maximum of 5%), therefore within the limits of the international recommendations for this kind of instrument. (author)

High power beam profile monitor with optical transition radiation

International Nuclear Information System (INIS)

Denard, J.C.; Piot, P.; Capek, K.; Feldl, E.

1997-01-01

A simple monitor has been built to measure the profile of the high power beam (800 kW) delivered by the CEBAF accelerator at Jefferson Lab. The monitor uses the optical part of the forward transition radiation emitted from a thin carbon foil. The small beam size to be measured, about 100 μm, is challenging not only for the power density involved but also for the resolution the instrument must achieve. An important part of the beam instrumentation community believes the radiation being emitted into a cone of characteristic angle 1/γ is originated from a region of transverse dimension roughly λγ; thus the apparent size of the source of transition radiation would become very large for highly relativistic particles. This monitor measures 100 μm beam sizes that are much smaller than the 3.2 mm λγ limit; it confirms the statement of Rule and Fiorito that optical transition radiation can be used to image small beams at high energy. The present paper describes the instrument and its performance. The authors tested the foil in, up to 180 μA of CW beam without causing noticeable beam loss, even at 800 MeV, the lowest CEBAF energy

Lovastatin attenuates ionizing radiation-induced normal tissue damage in vivo

International Nuclear Information System (INIS)

Ostrau, Christian; Huelsenbeck, Johannes; Herzog, Melanie; Schad, Arno; Torzewski, Michael; Lackner, Karl J.; Fritz, Gerhard

2009-01-01

Background and purpose: HMG-CoA-reductase inhibitors (statins) are widely used lipid-lowering drugs. Moreover, they have pleiotropic effects on cellular stress responses, proliferation and apoptosis in vitro. Here, we investigated whether lovastatin attenuates acute and subchronic ionizing radiation-induced normal tissue toxicity in vivo. Materials and methods: Four hours to 24 h after total body irradiation (6 Gy) of Balb/c mice, acute pro-inflammatory and pro-fibrotic responses were analyzed. To comprise subchronic radiation toxicity, mice were irradiated twice with 2.5 Gy and analyses were performed 3 weeks after the first radiation treatment. Molecular markers of inflammation and fibrosis as well as organ toxicities were measured. Results: Lovastatin attenuated IR-induced activation of NF-κB, mRNA expression of cell adhesion molecules and mRNA expression of pro-inflammatory and pro-fibrotic marker genes (i.e. TNFα, IL-6, TGFβ, CTGF, and type I and type III collagen) in a tissue- and time-dependent manner. γH2AX phosphorylation stimulated by IR was not affected by lovastatin, indicating that the statin has no major impact on the induction of DNA damage in vivo. Radiation-induced thrombopenia was significantly alleviated by lovastatin. Conclusions: Lovastatin inhibits both acute and subchronic IR-induced pro-inflammatory and pro-fibrotic responses and cell death in normal tissue in vivo. Therefore, lovastatin might be useful for selectively attenuating acute and subchronic normal tissue damage caused by radiotherapy.

DEVELOPMENT OF SHORT UNDULATORS FOR ELECTRON-BEAM-RADIATION INTERACTION STUDIES

Energy Technology Data Exchange (ETDEWEB)

Piot, P. [NICADD, DeKalb; Andorf, M. B. [NICADD, DeKalb; Fagerberg, G. [Northern Illinois U.; Figora, M. [Northern Illinois U.; Sturtz, A. [Northern Illinois U.

2016-10-19

Interaction of an electron beam with external field or its own radiation has widespread applications ranging from coherent-radiation generation, phase space cooling or formation of temporally-structured beams. An efficient coupling mechanism between an electron beam and radiation field relies on the use of a magnetic undulator. In this contribution we detail our plans to build short (11-period) undulators with 7-cm period refurbishing parts of the aladdin U3 undulator [1]. Possible use of these undulators at available test facilities to support experiments relevant to cooling techniques and radiation sources are outlined.

Dosimetric methodology and reference system for diagnostic level X radiation

International Nuclear Information System (INIS)

Potiens, Maria da Penha Albuquerque

1999-01-01

Several methodologies for the calibration of diagnostic radiology instruments were developed and established at the Calibration Laboratory of IPEN. These established radiation qualities are recommended by international standards. The methods may be used in the calibration procedures of survey meters used in radiation protection measurements (scattered radiation), instruments used in direct beams (attenuated and non attenuated beams) and quality control instruments. A reference system was proposed using two identical ionization chambers developed at IPEN. They differ only by the collecting electrode material, one of aluminium and the other of graphite. The different energetic dependence of the chamber's response provided a ratio related to the tube potential. The variation of only 0.28%, from 14.3 to 111 keV, on the energetic dependence of the graphite electrode chamber, provided the possibility of air kerma rate determination in the studied radiation beams. (author)

Transport and attenuation of radiations

CERN Document Server

Nimal, J C

2003-01-01

This article treats of the calculation methods used for the dimensioning of the protections against radiations. The method consists in determining for a given point the flux of particles coming from a source at a given time. A strong attenuation (of about some few mu Sv.h sup - sup 1) is in general expected between the source and the areas accessible to the personnel or the public. The calculation has to take into account a huge number of radiation-matter interactions and to solve the integral-differential transport equation which links the particles flux to the source. Several methods exist from the simplified physical model with numerical developments to the more or less precise resolution of the transport equation. These methods allows also the calculation of the uncertainties of equivalent dose rates, heat sources, structure damages using the data covariances (efficient cross-sections, modeling, etc..): 1 - transport equation; 2 - Monte-Carlo method; 3 - semi-numerical methods S sub N; 4 - methods based o...

Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

Science.gov (United States)

Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

2016-11-01

Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and the lessons learned from this process are presented.

Observation of the undulator radiation from the positron beam

International Nuclear Information System (INIS)

Maezawa, Hideki.

1986-02-01

A spectral measurement of the 1st harmonic of the undulator radiation emitted from positron beam was made on Dec. 21, 1985 during a test operation of the Photon Factory storage ring with the 2.5 GeV positron beam which was stored up to 5.5 mA. In comparison to the same measurement performed with the electron beam, no appreciable difference in the spectral properties of the undulator radiation was found between the two cases under the condition of the low beam current of a few mA. (author)

Attenuation and Emittance Growth of 450 GeV and 7 TeV Proton Beams in Low-Z Absorber Elements

CERN Document Server

Kadi, Y; Goddard, B; Schmidt, R

2004-01-01

The intensity of the LHC beams will be several orders of magnitude above the damage thresholds for equipment. Passive protection of accelerator equipment against failures during beam transfer, injection and dumping of the beam with diluters and collimators is foreseen. These protection devices must be robust in case of beam impact, and low-Z materials such as carbon are favored. In these diluters, the reduction of the energy density is determined both by the attenuation due to inelastic nuclear collisions and by the emittance growth of the surviving protons due to elastic scattering processes. The physics principles leading to attenuation and emittance growth for a hadron beam traversing matter are summarised, and FLUKA simulation results for 450 GeV and 7 TeV proton beams on low-Z absorbers are compared with these predictions. Design criteria for the LHC absorbers are derived from these results.

Arbitrary Control of Polarization and Intensity Profiles of Diffraction-Attenuation-Resistant Beams along the Propagation Direction

Science.gov (United States)

Corato-Zanarella, Mateus; Dorrah, Ahmed H.; Zamboni-Rached, Michel; Mojahedi, Mo

2018-02-01

We report on the theory and experimental generation of a class of diffraction-attenuation-resistant beams with state of polarization (SOP) and intensity that can be controlled on demand along the propagation direction. This control is achieved by a suitable superposition of Bessel beams, whose parameters are systematically chosen based on closed-form analytic expressions provided by the frozen waves method. Using an amplitude-only spatial light modulator, we experimentally demonstrate three scenarios. In the first, the SOP of a horizontally polarized beam evolves to radial polarization and is then changed to vertical polarization, with the beam intensity held constant. In the second, we simultaneously control the SOP and the longitudinal intensity profile, which is chosen such that the beam's central ring can be switched off over predefined space regions, thus generating multiple foci with different SOPs and at different intensity levels along the propagation. Finally, the ability to control the SOP while overcoming attenuation inside lossy fluids is shown experimentally. We envision our proposed method to be of great interest for many applications, such as optical tweezers, atom guiding, material processing, microscopy, and optical communications.

Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation

International Nuclear Information System (INIS)

Osterhuber, R.; Condreva, K.

1998-01-01

Incoming, background cosmic radiation constantly fluxes through the earth's atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters' worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location

21 CFR 892.5710 - Radiation therapy beam-shaping block.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiation therapy beam-shaping block. 892.5710 Section 892.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... block. (a) Identification. A radiation therapy beam-shaping block is a device made of a highly...

Radiation monitoring and beam dump system of the OPAL silicon microvertex detector

CERN Document Server

Braibant, S

1997-01-01

The OPAL microvertex silicon detector radiation monitoring and beam dump system is described. This system was designed and implemented in order to measure the radiation dose received at every beam crossing and to induce a fast beam dump if the radiation dose exceeds a given threshold.

Composites with carbon nanotube for radiation shielding application

International Nuclear Information System (INIS)

Fontainha, Críssia C.P.; Nunes, Modesto; Rosas, Víctor A.

2017-01-01

Polymeric composites filled with attenuating metals and functionalized with carbon nanotubes (NTC) are being largely developed. New attenuators materials have been widely investigated for radiation shielding to apply in procedures as interventional radiology, Computed Tomography (CT) and nuclear medicine. In this work composites for radiation attenuation in radiodiagnostic imaging procedures made of inorganic material as filler, by a sol-gel method, in poly(vinylidene fluoride-tryfluorethylene) [P(VDF-TrFE] copolymers that are used as the polymeric matrix. Two different metal attenuators were used as fillers: zirconia stabilized by yttria (8% wt.) and bismuth oxide. Carbon nanotubes were added with different concentrations at the solution of attenuator metal under controlled magnetic stirring. Characterization of composites by FTIR, UV-Vis, DSC and SEM-EDS were carried out. In a previous analysis of radiation attenuation, was used an incident monochromatic X-ray beam from the RIGAKU diffractometer. In this setup, one reference measure is directly exposed to the x-rays being diffracted by single crystal of Si (111). Another measure the attenuated beam is performed with the composite sample under detector. The functionalization of the carbon nanotube of multiple walls (MWNCT) in the in the P(VDF-TrFE) was evaluated. The samples present a good dispersion of the attenuator metal into presence at methacrylic acid. The cheap tube presented better dispersion in the polymer matrix than the 3100 nanotubes. Bismuth oxidation composites showed a better attenuation factor compared to Zirconia stabilized by yttria composites. (author)

Composites with carbon nanotube for radiation shielding application

Energy Technology Data Exchange (ETDEWEB)

Fontainha, Críssia C.P.; Nunes, Modesto; Rosas, Víctor A., E-mail: crissia@gmail.com [Universidade Federal de Minas Gerais (IMA/UFMG), Belo Horizonte, MG (Brazil). Dept. de Anatomia e Imagem; Santos, Adelina P.; Furtado, Clascídia A.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Polymeric composites filled with attenuating metals and functionalized with carbon nanotubes (NTC) are being largely developed. New attenuators materials have been widely investigated for radiation shielding to apply in procedures as interventional radiology, Computed Tomography (CT) and nuclear medicine. In this work composites for radiation attenuation in radiodiagnostic imaging procedures made of inorganic material as filler, by a sol-gel method, in poly(vinylidene fluoride-tryfluorethylene) [P(VDF-TrFE] copolymers that are used as the polymeric matrix. Two different metal attenuators were used as fillers: zirconia stabilized by yttria (8% wt.) and bismuth oxide. Carbon nanotubes were added with different concentrations at the solution of attenuator metal under controlled magnetic stirring. Characterization of composites by FTIR, UV-Vis, DSC and SEM-EDS were carried out. In a previous analysis of radiation attenuation, was used an incident monochromatic X-ray beam from the RIGAKU diffractometer. In this setup, one reference measure is directly exposed to the x-rays being diffracted by single crystal of Si (111). Another measure the attenuated beam is performed with the composite sample under detector. The functionalization of the carbon nanotube of multiple walls (MWNCT) in the in the P(VDF-TrFE) was evaluated. The samples present a good dispersion of the attenuator metal into presence at methacrylic acid. The cheap tube presented better dispersion in the polymer matrix than the 3100 nanotubes. Bismuth oxidation composites showed a better attenuation factor compared to Zirconia stabilized by yttria composites. (author)

Gamma-ray attenuation to measure water contents and/or bulk densities of porous materials

International Nuclear Information System (INIS)

Ferraz, E.S.B.

1983-01-01

Attenuation of gamma radiation during transmission through soil and porous materials has been used for approximately three decades as a method for determining volumetric water content, theta, and bulk density, rho. This method is particularly suited for laboratory determinations of theta and rho in soil columns but it also has been used with success under field conditions. Measurements of attentuation of a collimated beam of monoernergetic gamma-rays has been used successfully by many investigators to provide rapid, non-destructive determinations for small volumes of soil. For stable soils, i.e. soils which do not swell upon wetting or shrink upon drying, rho may be assumed to remain constant during water flow through the soil, and thus changes in intensity or transmitted radiation may be attributed to changes in water content, theta. However, for unstable soils, the dry bulk density is subject to change with time during water flow through the soil and cannot be assumed to be a constant. Several investigators have utilized either a single beam of dual-energy gamma photons or two separate monoenergetic photon beams with greatly different energies to simultaneously determine theta and rho in these soils. A general review of gamma-ray attenuation methods for determining theta and rho in laboratory soil cores and in field soil profiles is reported in this paper. Theoretical equations for transmission and attenuation of gamma radiation in soils are presented for both single and double beams of gamma photons. Sensitivity, precision, accuracy, and experimental errors for the method are evaluated and discussed with respect to the theory. (author)

Electron beam instrumentation techniques using coherent radiation

International Nuclear Information System (INIS)

Wang, D.X.

1997-01-01

Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed

Foundations of radiation physics and radiation protection. 5. ed.; Grundlagen der Strahlungsphysik und des Strahlenschutzes

Energy Technology Data Exchange (ETDEWEB)

Krieger, Hanno

2017-07-01

The following topics are dealt with: Types of radiation and radiation fields, the atomic structure, radioactive decays, decay law, natural and artificial radioactivity, interactions of ionizing photon radiation, attenuation of neutral-particle beams, interactions of neutron radiation, interactions of charged particles, ionization and energy transfer, radiation doses, radiation protection phantoms, foundations of the radiation biology of cells, effects and risks of ionizing radiation, radiation expositions of men with ionizing radiation, radiation protection law, practical radiation protection against ionizing radiations, radiation eposures in medical radiology. (HSI)

Use of two monoenergetic gamma-ray attenuation method in wood samples

International Nuclear Information System (INIS)

Mortatti, J.; Nascimento Filho, V.F. do; Barros Ferraz, E.S. de

1983-01-01

The mass attenuation coefficients for 10 wood species were determined employing the gamma attenuation technique with a single beam comprising two monoenergetics gamma energies from 137 Cs/sup(137m) Ba and 141 Am (662 and 59,6 KeV, respectively). The absorbed radiation was simultaneously measured by means of a 3'' x 3'' Nal (T1) planar solid scintillator crystal connected to a two channel gamma spectrometer. The effect of the 137 Cs/ sup(137m) Ba compton radiation on the not 241 Am counting rates were corrected. Dead time effects were desregarded, as the counting rates were always below 10 5 cpm. (Author) [pt

Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

DEFF Research Database (Denmark)

Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.

1965-01-01

Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...

Critical analysis of soil hydraulic conductivity determination using monoenergetic gamma radiation attenuation

International Nuclear Information System (INIS)

Portezan Filho, Otavio

1997-01-01

Three soil samples of different textures: LVA (red yellow latosol), LVE (dark red latosol) and LRd (dystrophic dark red latosol) were utilized for unsaturated hydraulic conductivity K(θ) measurements. Soil bulk densities and water contents during internal water drainage were measured by monoenergetic gamma radiation attenuation, using homogeneous soil columns assembled in the laboratory. The measurements were made with a collimated gamma beam of 0.003 m in diameter using a Nal(Tl) (3'' x 3 '') detector and a 137 Cs gamma source of 74 X 10 8 Bq and 661.6 KeV. Soil columns were scanned with the gamma beam from 0.01 to 0.20 m depth, in 0.01m steps, for several soil water redistribution times. The results show a great variability of the unsaturated hydraulic conductivity relation K(θ), even though homogeneous soils were used. The variability among methods is significantly smaller in relation to variability in space. The assumption of unit hydraulic gradient during redistribution of soil water utilized in the methods of Hillel, Libardi and Sisson leads to hydraulic conductivity values that increase in depth. The exponential character of the K(θ) relationship, is responsible for the difficulty of estimating soil hydraulic conductivity, which is a consequence of small variations in the porous arrangement, even in samples supposed to be homogeneous. (author)

Effect of electron beam radiations on anxiety in experimental animal models

International Nuclear Information System (INIS)

Deepa, B; Suchetha Kumari; Sanjeev, Ganesh; Rao, Satheesh

2013-01-01

Exposures to ionizing radiation have been an inevitable part of the environment. This type of radiation can disrupt atoms, creating positive and negative charged particles, and cause biological harm. Ionizing radiation includes X-rays, gamma rays, alpha particles, beta particles and neutrons. They have the potential to cause both beneficial and harmful effects. There are concerns about these radiations as they are widely used in hospitals for treatment and diagnosis of various diseases. The present work was designed to test the effect of whole body electron beam radiation on anxiety in mice using the Elevated plus maze and Light dark arena, the commonly used models for assessing anxiety in rodents. Mice were irradiated with three different doses (2 Gy, 4 Gy and 6 Gy) of electron beam radiations. Statistical analysis revealed that whole body irradiation of the moderate dose range (2-6 Gy) of electron beam leads to a significant (p<0.001) anxiogenic activity in irradiated mice. Electron beam induced anxiety can be due to radiation induced reactive oxygen species in brain. (author)

Dosimetry of beams for negative pi-meson radiation therapy

International Nuclear Information System (INIS)

Dicello, J.F.

1976-01-01

Several new facilities have been built in the last few years which can produce high intensity beams of pions. As a result, a significant amount of new data related to pion dosimetry is available. Results of beam composition, beam shaping, and collimation are given along with depth dose curves and isodose contours. Experimental data which describe the radiation quality of pion beams and the change in radiation quality with position are presented. Experimental data determining the fraction of the dose resulting from neutrons are discussed. The present techniques used in pion dosimetry are summarized, and those areas of pion dosimetry which require additional effort in order to achieve routine treatment planning for patients are reviewed

PEP radiation shielding tests in SLAC A Beam

International Nuclear Information System (INIS)

Ash, W.; DeStaebler, H.; Harris, J.; Jenkins, T.; Murray, J.

1977-09-01

Radiation shielding tests designed to simulate possible conditions in and around the PEP experimental halls were conducted. The SLAC A Beam was targeted in the block tunnel at a point about midway between End Station A and Beam Dump East. At that site it was relatively easy to rearrange the concrete block structure to simulate the various shielding configurations under consideration for PEP. Extensive surveys of neutron and ionizing radiation were made. Complete results of the shielding tests are given

Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

Energy Technology Data Exchange (ETDEWEB)

Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)

1996-09-01

Exposure of rats to 5-10 Gy of ionizing radiation produces hyperthermia and reduces motor activity. Previous studies suggested that radiation-induced hyperthermia results from a relatively direct action on the brain and is mediated by prostaglandins. To test the hypothesis that hypoactivity may be, in part, a thermoregulatory response to this elevation in body temperature, adult male rats were given indomethacin (0.0, 0.5, 1.0, and 3.0 mg/kg, intraperitoneally), a blocker of prostaglandin synthesis, and were either irradiated (LINAC 18.6 MeV (nominal) high-energy electrons, 10 Gy at 10 Gy/min, 2.8 {mu}sec pulses at 2 Hz) or sham-irradiated. The locomotor activity of all rats was then measured for 30 min in a photocell monitor for distance traveled and number of vertical movements. Rectal temperatures of irradiated rats administered vehicle only were elevated by 0.9{+-}0.2degC at the beginning and the end of the activity session. Although indomethacin, at the two higher doses tested, attenuated the hyperthermia in irradiated rats by 52-75%, it did not attenuate radiation-induced reductions in motor activity. These results indicate that motor hypoactivity after exposure to 10 Gy of high-energy electrons is not due to elevated body temperature or to the increased synthesis of prostaglandins. (author)

Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

International Nuclear Information System (INIS)

Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R.

1996-01-01

Exposure of rats to 5-10 Gy of ionizing radiation produces hyperthermia and reduces motor activity. Previous studies suggested that radiation-induced hyperthermia results from a relatively direct action on the brain and is mediated by prostaglandins. To test the hypothesis that hypoactivity may be, in part, a thermoregulatory response to this elevation in body temperature, adult male rats were given indomethacin (0.0, 0.5, 1.0, and 3.0 mg/kg, intraperitoneally), a blocker of prostaglandin synthesis, and were either irradiated (LINAC 18.6 MeV (nominal) high-energy electrons, 10 Gy at 10 Gy/min, 2.8 μsec pulses at 2 Hz) or sham-irradiated. The locomotor activity of all rats was then measured for 30 min in a photocell monitor for distance traveled and number of vertical movements. Rectal temperatures of irradiated rats administered vehicle only were elevated by 0.9±0.2degC at the beginning and the end of the activity session. Although indomethacin, at the two higher doses tested, attenuated the hyperthermia in irradiated rats by 52-75%, it did not attenuate radiation-induced reductions in motor activity. These results indicate that motor hypoactivity after exposure to 10 Gy of high-energy electrons is not due to elevated body temperature or to the increased synthesis of prostaglandins. (author)

Cherenkov Radiation from a Pseudospark-sourced Electron Beam

International Nuclear Information System (INIS)

Phelps, A.D.R.; Yin, H.; Cross, A.W.; He, W.; Ronald, K.

2003-01-01

Electron beam generation from a multi-gap pseudospark discharge was investigated. A pseudospark-sourced electron beam has two phases, an initial hollow cathode phase (HCP) beam followed by a conductive phase (CP) beam. The beam brightness was measured by a field-free collimator to be 109 and 1011 Am-2rad-2 for the hollow cathode phase (HCP) beam and the conductive phase (CP) beam respectively. The initial HCP beam from an eight-gap pseudospark discharge was applied in a Cherenkov interaction between the electron beam and the TM01 mode of a 60-cm long alumina-lined waveguide. It was found experimentally that significant microwave radiation was generated only when the dielectric was present in the interaction space. If there was no dielectric in the cylindrical waveguide, then a very small background microwave output was detected even when the guide B-field was absent. This demonstrated, in conjunction with the observation that the microwave output signal was independent of the guide magnetic field over the range 0.13 to 0.26 T, that the radiation from the experiment was due to the Cherenkov interaction mechanism. In addition, two components of the microwave pulse were observed corresponding to the two energy components of the electron beam during the pseudospark discharge breakdown. These results demonstrated that the microwave radiation was generated by Cherenkov amplification of the broadband emission from the pseudospark discharge itself. A background signal level of around 100 W was measured in the frequency range 20 - 50 GHz with a percentage of (2.7 ± 0.6)% in the frequency range 25.5 - 28.6 GHz, when the dielectric lining was removed from the maser. The frequency of the microwave output after the Cherenkov maser interaction was measured to be mainly around 25.5 GHz and the dominating mode was identified as being TM01. The duration of the microwave pulse was approximately 80 ns, with a peak power of around 2 ± 0.2 kW. The gain of this amplifier was measured

Measure of the attenuation curve of a beam of X-rays with TLD-100 dosimeters of LiF; Medicion de la curva de atenuacion de un haz de rayos X con dosimetros TLD-100 de LiF

Energy Technology Data Exchange (ETDEWEB)

Bonzi, E. V.; Mainardi, R. T. [Universidad Nacional de Cordoba, Facultad de Matematica, Astronomia y Fisica, Av. Haya de la Torre y Av. Medina Allende s/n, Ciudad Universitaria, Cordoba (Argentina); Germanier, A. [Ministerio de Ciencia y Tecnologia, Ceprocor, Unidad de Estudios Fisicos, Alvarez de Arenas 230, X5004AAP Barrio Juniors, Cordoba (Argentina); Delgado, V. [Universidad Complutense de Madrid, Departamento de Fisica Medica, Ciudad Universitaria, 28040 Madrid (Spain)

2011-10-15

The attenuation curve of a beam of X-rays represents the beam intensity in function of the attenuator thickness interposed between the source and the detector. To know with the major possible precision the attenuation curve is indispensable in procedures of spectral reconstruction. Their periodic measuring also offers valuable information on the correct operation of a tube of X-rays, diagnostic or therapy, when not have a specific detector for that activity. In this work was measured the attenuation curve of a tube of X-rays operated to 50 kV and 0.5 ma, using existent elements in any diagnostic or therapy laboratory with radiations. In the measures commercial aluminum foil was used, bent until 24 times and thermoluminescent dosimeters TLD 100 - LiF. Also, for comparison, was measured this attenuation curve with an ionization chamber brand Capintec model 192. Was determined by X-rays fluorescence the composition of the aluminium foil, since the present elements in the alloy can to affect the form of the attenuation curve. It is interesting to observe that these elements are in very low proportion (ppm) that they do not alter the attenuation capacity of the pure aluminium. Finally in a precision balance we weigh a big piece (30 cm x 100 cm) of aluminium foil and we obtained the thickness in g/c m2. It is possible to obtain attenuation curves of a beam of X-rays, with a high precision procedure and reproducibility. The use of TLD-100 dosimeters of LiF or similar makes that this activity was also quick and simple. (Author)

Generation of linearly polarized resonant transition radiation X-ray beam

International Nuclear Information System (INIS)

Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu

2000-01-01

We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-μm thick Kapton foil stack. (author)

Generation of linearly polarized resonant transition radiation X-ray beam

Energy Technology Data Exchange (ETDEWEB)

Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

2000-03-01

We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-{mu}m thick Kapton foil stack. (author)

A simple method of dosimetry for E-beam radiation

International Nuclear Information System (INIS)

Spencer, D.S.; Thalacker, V.P.; Chasman, J.N.; Siegel, S.

1985-01-01

A simple method utilizing a photochromic 'intensity label' for monitoring electron-beam sources was evaluated. The labels exhibit a color change upon exposure to UV or e-beam radiation. A correlation was found between absorbed energy and Gardner Color Index at low electron-beam doses. (author)

Evaluation of PVDF/MWCNT - ZRO{sub 2} nanocomposites for X-Rays attenuation

Energy Technology Data Exchange (ETDEWEB)

Pereira, Esther L.M.; Oliveira, Arno H., E-mail: esther_machado@outlook.com.br, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (CCTN/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Batista, Adriana S.M., E-mail: adriananuclear@yahoo.com.br [Departamento de Anatomia e Imagem (IMA), Belo Horizonte, MG (Brazil); Ribeiro, Fabíola A.S.; Santos, Adelina P.; Faria, Luiz O., E-mail: adelina@cdtn.br, E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Recently, polymer-based nanocomposites filled with zirconium oxide (ZrO{sub 2}) nanoparticles have been suggested to be used in radiology procedures as X-rays attenuators. On the other hand, multi walled carbon nanotubes (MWCNT) has been reported to have enhanced X-rays attenuation features, when compared to other materials. In this work polymer-based nanocomposites made of a poly(vinylidene fluoride) [PVDF] homopolymer co-filled with MWCNT and zirconia (ZrO{sub 2}) were prepared, in order to investigate them for radiation shielding purposes. The PVDF matrix was added to 1.3% ZrO{sub 2} and the MWCNT in three different proportions: 0.33%, 0.66% and 1% of MWCNT.The arrangement between these materials causes new properties to be introduced to the constituents due to morphological modifications or electronic interactions between them, resulting in a nanocomposite of higher properties. The radiation shielding characterization was performed by using the X-ray beam of a XRD equipment. Photons with energies of 6.5 keV, 17.5 keV and 22.1 keV, corresponding to the anodes of cobalt, molybdenum and silver respectively, were used. The results are discussed in terms of the attenuation percentage of the nanocomposites produced in relation to the energy of the exposed radiation beam and varying the thickness of the samples. A comparison with cataloged aluminum data is also performed. (author)

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

Study of hard braking x-ray radiation on the radiation-beam complex ''TEMP''

International Nuclear Information System (INIS)

Batrakov, A.B.; Glushko, E.G.; Egorov, A.M.; Zinchenko, A.A.; Litvinenko, V.V.; Lonin, Yu.F.; Ponomarev, A.G.; Rybka, A.V.; Fedotov, S.I.; Uvarov, V.T.

2015-01-01

A calculation over of basic parameters of the hard brake x-rayed radiation for the microsecond accelerating of relativistic electronic beam T EMP . Optimization of converters is conducted for these aims. Maximal doses are experimentally got brake x-rayed radiation on beam-radiation complex T EMP . The diagrams of orientation of the brake x-rayed radiation are taken off depending on energies of bunches and forms of electrodes.

Opto-microwave, Butler matrixes based front-end for a multi-beam large direct radiating array antenna

Science.gov (United States)

Piqueras, M. A.; Mengual, T.; Navasquillo, O.; Sotom, M.; Caille, G.

2017-11-01

The evolution of broadband communication satellites shows a clear trend towards beam forming and beamswitching systems with efficient multiple access schemes with wide bandwidths, for which to be economically viable, the communication price shall be as low as possible. In such applications, the most demanding antenna concept is the Direct Radiating Array (DRA) since its use allows a flexible power allocation between beams and may afford failures in their active chains with low impact on the antenna radiating pattern. Forming multiple antenna beams, as for `multimedia via satellite' missions, can be done mainly in three ways: in microwave domain, by digital or optical processors: - Microwave beam-formers are strongly constrained by the mass and volume of microwave devices and waveguides - the bandwidth of digital processors is limited due to power consumption and complexity constraints. - The microwave photonics is an enabling technology that can improve the antenna feeding network performances, overcoming the limitations of the traditional technology in the more demanding scenarios, and may overcome the conventional RF beam-former issues, to generate accurately the very numerous time delays or phase shifts required in a DRA with a large number of beams and of radiating elements. Integrated optics technology can play a crucial role as an alternative technology for implementing beam-forming structures for satellite applications thanks to the well known advantages of this technology such as low volume and weight, huge electrical bandwidth, electro-magnetic interference immunity, low consumption, remote delivery capability with low-attenuation (by carrying all microwave signals over optical fibres) and the robustness and precision that exhibits integrated optics. Under the ESA contract 4000105095/12/NL/RA the consortium formed by DAS Photonics, Thales Alenia Space and the Nanophotonic Technology Center of Valencia is developing a three-dimensional Optical Beamforming

Introduction to radiological physics and radiation dosimetry

CERN Document Server

Attix, Frank Herbert

2004-01-01

A straightforward presentation of the broad concepts underlying radiological physics and radiation dosimetry for the graduate-level student. Covers photon and neutron attenuation, radiation and charged particle equilibrium, interactions of photons and charged particles with matter, radiotherapy dosimetry, as well as photographic, calorimetric, chemical, and thermoluminescence dosimetry. Includes many new derivations, such as Kramers X-ray spectrum, as well as topics that have not been thoroughly analyzed in other texts, such as broad-beam attenuation and geometrics, and the reciprocity theorem

Radiation protection in hospitals

International Nuclear Information System (INIS)

MOuld, R.F.

1985-01-01

A book on radiation protection in hospitals has been written to cater for readers with different backgrounds, training and needs by providing an elementary radiation physics text in Part I and an advanced, comprehensive Part II relating to specific medical applications of X-rays and of radioactivity. Part I includes information on basic radiation physics, radiation risk, radiation absorption and attenuation, radiation measurement, radiation shielding and classification of radiation workers. Part II includes information on radiation protection in external beam radiotherapy, interstitial source radiotherapy, intracavitary radiotherapy, radioactive iodine-131 radiotherapy, nuclear medicine diagnostics and diagnostic radiology. (U.K.)

Design, construction and characterization of special ionization chambers for X radiation beams monitoring

International Nuclear Information System (INIS)

Yoshizumi, Maira Tiemi

2010-01-01

X radiation equipment may show fluctuations in the radiation beam intensity, as they are connected to the power net. These intensity variations can, in turn, modify the air kerma rate produced by this radiation beam. In a calibration laboratory, where radiation detectors (from clinics and hospital services) are calibrated, variations in the radiation beam intensity may cause an error in the absorbed dose determination. The monitor ionization chambers are used to verify the radiation beam intensity constancy, and to provide a correction for possible fluctuations. In this work, monitor ionization chambers for X radiation beams were designed, assembled and characterized. The developed ionization chambers have an innovative design, ring-shaped, with aluminium or graphite electrodes. These ring-shaped ionization chambers have the advantage of not interfering in the direct radiation beams. A double-volume ionization chamber with graphite electrodes was also developed. This ionization chamber is similar to the commercial monitor ionization chamber used in the Calibration Laboratory of the Instituto de Pesquisas Energeticas e Nucleares. All developed ionization chambers were tested in several standardized radiation beams and their performances were compared with those of commercial ionization chambers. The results show that two of the four ionization chambers developed showed performance comparable to that of the commercial ionization chambers tested. Besides presenting good results, the ionization chambers were designed and manufactured using low cost materials, which are easily found on the Brazilian market. (author)

Radiation processing of carrageenan using electron beam

International Nuclear Information System (INIS)

Abad, L.V.; Aranilla, C.T.; Relleve, L.; Dela Rosa, A.M.

2005-01-01

Electron beam accelerator has been widely employed in the modification of natural polymers for the development of materials used in biomedical and agricultural applications. The carrageenans are among these materials that show a vast potential for these types of applications. Previous studies at the Philippine Nuclear Research Institute focused on the utilization of gamma radiation to modify the carrageenans. Radiation degradation of carrageenan found valuable use as plant growth promoter. Hydrogels for burn dressing using blends of carrageenan and synthetic polymers have also been made using gamma radiation. While previous studies have been focused on the use of gamma radiation to modify the carrageenans, recent studies expanded the technology to electron beam. Concretely, researches are along the following two areas: a) Degradation studies of aqueous carrageenan using the LEEB and b) Preparation of blend polysaccharide derivatives such as carboxymethylcellulose (CMC), and hydroxypropylcellulose (HPC) with kappa-carrageenan (KC) by EB radiation. These works were done at the Takasaki Radiation Chemistry Research Establishment (TRCRE) by two PNRI colleagues under the nuclear researcher exchange program of the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT). The first area had already been reported and discussed in the last project meeting held in Malaysia. (author)

Imaging and characterization of primary and secondary radiation in ion beam therapy

Energy Technology Data Exchange (ETDEWEB)

Granja, Carlos, E-mail: carlos.granja@utef.cvut.cz; Opalka, Lukas [Institute of Experimental and Applied Physics, Czech Technical University in Prague (Czech Republic); Martisikova, Maria; Gwosch, Klaus [German Cancer Research Center, Heidelberg (Germany); Jakubek, Jan [Advacam, Prague (Czech Republic)

2016-07-07

Imaging in ion beam therapy is an essential and increasingly significant tool for treatment planning and radiation and dose deposition verification. Efforts aim at providing precise radiation field characterization and online monitoring of radiation dose distribution. A review is given of the research and methodology of quantum-imaging, composition, spectral and directional characterization of the mixed-radiation fields in proton and light ion beam therapy developed by the IEAP CTU Prague and HIT Heidelberg group. Results include non-invasive imaging of dose deposition and primary beam online monitoring.

Influence of beam divergence on form-factor in X-ray diffraction radiation

International Nuclear Information System (INIS)

Sergeeva, D.Yu.; Tishchenko, A.A.; Strikhanov, M.N.

2015-01-01

Diffraction radiation from divergent beam is considered in terms of radiation in UV and X-ray range. Scedastic form of Gaussian distribution of the particle in the bunch, i.e. Gaussian distribution with changing dispersion has been used, which is more adequate for description of divergent beams than often used Gaussian distribution with constant dispersion. Both coherent and incoherent form-factors are taken into account. The conical diffraction effect in diffraction radiation is proved to make essential contribution in spectral-angular characteristics of radiation from a divergent beam

Imaging and characterization of primary and secondary radiation in ion beam therapy

International Nuclear Information System (INIS)

Granja, Carlos; Opalka, Lukas; Martisikova, Maria; Gwosch, Klaus; Jakubek, Jan

2016-01-01

Imaging in ion beam therapy is an essential and increasingly significant tool for treatment planning and radiation and dose deposition verification. Efforts aim at providing precise radiation field characterization and online monitoring of radiation dose distribution. A review is given of the research and methodology of quantum-imaging, composition, spectral and directional characterization of the mixed-radiation fields in proton and light ion beam therapy developed by the IEAP CTU Prague and HIT Heidelberg group. Results include non-invasive imaging of dose deposition and primary beam online monitoring.

Comparison of Techniques to Reduce Bremsstrahlung Background Radiation from Monoenergetic Photon Beams

International Nuclear Information System (INIS)

Johnson, M; McNabb, D

2006-01-01

An important applied technology is a tunable mono-energetic photon source [1]. These sources are made of relativistic electron accelerators coupled to low-energy lasers, which produce high-energy, mono-energetic-rays. One challenge associated with systems such as this is a continuum of bremsstrahlung background created when an electron beam passes through an aperture of some sort and the electron bunch or its halo impinges on the aperture pictured in figure 1. For instance, in the current T-REX [1] design for the interaction point between the laser- and electron-beam, the electron-beam passes through the center of a mirror used to reflect the laser. There is a potential with this design that bremsstrahlung radiation may be produced at the edges of the mirror openings and contaminate the mono-energetic photon beam. Certain applications [2] may be sensitive to this contamination. To reduce the bremsstrahlung contaminate a collimator (thickness ∼24in. (calculated from XCOM database [3]) to attenuate by a factor of 10 -3 the 112MeV photons expected in the T-REX demonstration [1]) is situated between the aperture and target. To maximize the brightness of the photon-beam, the collimator opening must be no less than the size of the photon-beam spot size expected to be about 1mm. This fixes the collimator opening. a priori the aperture size must be greater than the collimator opening and is a function distance between the aperture and collimator. In this paper we focus on two approaches to estimate the aperture size, given a collimator and a target whose sizes and distances from the aperture are given. In the next section we will discuss these approaches

Progress report on the neutral beam radiation hardening study

International Nuclear Information System (INIS)

Lee, J.D.; Condit, R.H.; Hoenig, C.L.; Wilcox, T.P.; Erickson, J.

1978-01-01

A neutral beam injector as presently conceived directly views the plasma it is sustaining. In turn the injector is exposed to the primary fusion neutrons plus secondary neutrons and gammas streaming back up the neutral beam duct. The intent of this work is to examine representative beam lines to see how performance and lifetimes could be affected by this radiation environment and to determine how unacceptable effects could be alleviated. Potential radiation induced problems addressed in this report have been limited to: (1) overheating of cryopanels and insulators, (2) gamma flux induced electrical conductivity increase of insulators, and (3) neutron and gamma fluence induced damage to insulator materials

ALICE Transition Radiation Detector (TRD), test beam.

CERN Multimedia

2003-01-01

Electrons and positrons can be discriminated from other charged particles using the emission of transition radiation - X-rays emitted when the particles cross many layers of thin materials. To develop such a Transition Radiation Detector(TRD) for ALICE many detector prototypes were tested in mixed beams of pions and electrons, as in the example shown here.

Impurity radiation from a beam-plasma neutron source

International Nuclear Information System (INIS)

Molvik, A.W.

1995-01-01

Impurity radiation, in a worst case evaluation for a beam-plasma neutron source (BPNS), does not limit performance. Impurities originate from four sources: (a) sputtering from walls by charge exchange or alpha particle bombardment, (b) sputtering from limiters, (c) plasma desorption of gas from walls and (d) injection with neutral beams. Sources (c) and (d) are negligible; adsorbed gas on the walls of the confinement chamber and the neutral beam sources is removed by the steady state discharge. Source (b) is negligible for impinging ion energies below the sputtering threshold (T i ≤ 0.025 keV on tungsten) and for power densities to the limiter within the capabilities of water cooling (30-40 MW/m 2 ); both conditions can be satisfied in the BPNS. Source (a) radiates 0.025 MW/m 2 to the neutron irradiation samples, compared with 5 to 10 MW/m 2 of neutrons; and radiates a total of 0.08 MW from the plasma column, compared with 60 MW of injected power. The particle bombardment that yields source (a) deposits an average of 2.7 MW/m 2 on the samples, within the capabilities of helium gas cooling (10 MW/m 2 ). An additional worst case for source (d) is evaluated for present day 2 to 5 s pulsed neutral beams with 0.1% impurity density and is benchmarked against 2XIIB. The total radiation would increase a factor of 1.5 to ≤ 0.12 MW, supporting the conclusion that impurities will not have a significant impact on a BPN. (author). 61 refs, 7 figs, 2 tabs

Study characteristics of new concrete mixes and their mechanical, physical, and gamma radiation attenuation features

Energy Technology Data Exchange (ETDEWEB)

El-Samrah, Moamen G.; Abdel-Rahman, Mohamed A.E. [Nuclear Engineering Department, Military Technical College Kobry El-kobbah, Cairo (Egypt); Kany, Amr M.I. [Physics Department, Faculty of Science, Al-Azhar University, Cairo (Egypt)

2018-02-01

Ordinary concrete and those of different compositions are regarded as suitable material in many applications concerning with gamma and neutron radiation shielding purposes. They are widely used in nuclear power plant, medical facilities, nuclear shelters, and for radioactive materials transportation as well as storage of radioactive wastes. In this study four different concrete mixes were prepared with the following different types of coarse aggregates: dolomite, barite, goethite, and steel slag. The effect of changes in the fine aggregates, selected to be 50 % local sand and 50 % limonite with addition of 10 % silica fume (SF) and 10 % fly ash (FA) by replacement of the total cement weight, on the performance of the samples was also investigated. To examine the performance of such samples for radiation shielding applications, a set of physical, mechanical, and radiation attenuation properties was studied and compared with those of ordinary concrete. This investigation includes compressive strength, slump test, bulk density, ultrasonic pulse velocity test, and gamma rays attenuation measurements for the different samples. A verification of the experimental results concerning the radiation attenuation measurements was performed using WinXcom program (Version 3.1). The experimental results revealed that all concrete mixes; goethite-limonite concrete (G.L), barite-limonite concrete (B.L), steel slag-limonite concrete (S.L) and dolomite concrete (D.C) have good physical and mechanical properties that successfully satisfying them as high performance concretes. In addition the barite-limonite and the steel slag-limonite have the higher γ-ray attenuation coefficients at low and high energy range and hence have a better radiation shielding. The obtained results from WinXcom program calculations showed a good agreement with the experimental results concerning γ-ray attenuation measurements for the studied concrete mixes. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGa

GPR measurements of attenuation in concrete

Science.gov (United States)

Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

2015-03-01

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

GPR measurements of attenuation in concrete

International Nuclear Information System (INIS)

Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

2015-01-01

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups

GPR measurements of attenuation in concrete

Energy Technology Data Exchange (ETDEWEB)

Eisenmann, David, E-mail: djeisen@cnde.iastate.edu; Margetan, Frank J., E-mail: djeisen@cnde.iastate.edu; Pavel, Brittney, E-mail: djeisen@cnde.iastate.edu [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

2015-03-31

Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

Optimal Background Attenuation for Fielded Radiation Detection Systems

International Nuclear Information System (INIS)

Robinson, Sean M.; Kaye, William R.; Schweppe, John E.; Siciliano, Edward R.

2006-01-01

Radiation detectors are often placed in positions difficult to shield from the effects of terrestrial background. This is particularly true in the case of Radiation Portal Monitor (RPM) systems, as their wide viewing angle and outdoor installations make them susceptible to terrestrial background from the surrounding area. A low background is desired in most cases, especially when the background noise is of comparable strength to the signal of interest. The problem of shielding a generalized RPM from terrestrial background is considered. Various detector and shielding scenarios are modeled with the Monte-Carlo N Particle (MCNP) computer code. Amounts of nominal-density shielding needed to attenuate the terrestrial background to varying degrees are given, along with optimal shielding geometry to be used in areas where natural shielding is limited, and where radiation detection must occur in the presence of natural background. Common shielding solutions such as steel plating are evaluated based on the signal to noise ratio and the benefits are weighed against the incremental cost.

Performance of a pencil ionization chamber in various radiation beams

International Nuclear Information System (INIS)

Maia, A.F.; Caldas, L.V.E.

2003-01-01

Pencil ionization chambers were recommended for use exclusively in the computed tomography (CT) dosimetry, and, from the start, they were developed only with this application in view. In this work, we studied the behavior of a pencil ionization chamber in various radiation beams with the objective of extending its application. Stability tests were performed, and calibration coefficients were obtained for several standard radiation qualities of the therapeutical and diagnostic levels. The results show that the pencil ionization chamber can be used in several radiation beams other than those used in CT

Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

Energy Technology Data Exchange (ETDEWEB)

Liu, Chuyu [Peking Univ., Beijing (China)

2012-12-31

Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

International Nuclear Information System (INIS)

Liu, Chuyu

2012-01-01

Beam diagnostics is an essential constituent of any accelerator, so that it is named as 'organs of sense' or 'eyes of the accelerator.' Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

Mass attenuation coefficients of X-rays in different barite concrete used in radiation protection as shielding against ionizing radiation

International Nuclear Information System (INIS)

Almeida, A. T. Jr.; Nogueira, M.S.; Santos, M.A.P.; Campos, L.L.; Araújo, F. G. S.

2015-01-01

The attenuation coefficient depends on the incident photon energy and the nature of the materials. In order to minimize exposure to individuals. Barite concrete has been largely used as a shielding material in installations housing gamma radiation sources as well as X-ray generating equipment. This study was conducted to evaluate the efficacy of different mixtures of barite concrete for shielding in diagnostic X-ray rooms. The mass attenuation coefficient (μ/ρ). The mass attenuation coefficients have been measured by employing the CdTe detector model XR-100T. The distance between the source and the exposed surface of all samples was measured by SSD light indicator of machine which was 350 cm. The slope of the linear plot of the intensity transmitted versus specimen thickness would yield the attenuation coefficient. The mass attenuation coefficients (μ/ρ) were compared with the tabulations based upon the results of the XCOM program. The rectangular barite concrete blocks in different thicknesses from were used for the radiation attenuation test. The experimental values were compared with theoretical values WinXcom. The plots of the logarithm of transmitted intensity versus specimen thickness were linear for all the samples and the µ/ρ was obtained from the plots by linear regression over the 25%-2% transmission range, under good geometrical condition. There is a good agreement between theoretical and experimental values, within the 9%. In fact over the entire transmission range of 25-2% the experimental and theoretical values agree well for both the energies. (authors)

Optical remote diagnostics of atmospheric propagating beams of ionizing radiation

Science.gov (United States)

Karl JR., Robert R.

1990-03-06

Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

Optical breakdown of helium in Bessel laser radiation beams

International Nuclear Information System (INIS)

Andreev, N E; Pleshanov, I V; Margolin, L Ya; Pyatnitskii, Lev N

1998-01-01

Numerical simulation is used to investigate the dynamics of formation of a helium plasma in Bessel beams, shaped by an axicon and a phase converter from a laser radiation pulse with Gaussian temporal and radial intensity profiles. The beam intensities at the breakdown threshold are determined as a function of the pulse duration for various radial field distributions in a beam characterised by Bessel functions of order m (m = 0 - 5). It is shown that in the investigated range of parameters the threshold intensity is independent of m. The temporal and spatial evolution of the resultant plasma, and the dependence of the plasma characteristics on the pulse parameters are considered. Conditions are found for the formation of tubular plasma channels in beams of orders m≥1. The adopted model of the optical breakdown of helium is shown to be satisfactory because of a good agreement between the results of calculations of the moment of breakdown in a zeroth-order Bessel beam and experimental results. (interaction of laser radiation with matter. laser plasma)

An alternative approach to compensators design for photon beams used in radiotherapy

International Nuclear Information System (INIS)

Jurkovic, S.; Zauhar, G.; Bistrovic, M.; Faj, D.; Kaliman, Z.; Smilovic Radojcic, D.

2007-01-01

The use of compensators in order to achieve desired dose distribution has a long history and is a well-established technique in radiation therapy planning. There are several different calculation methods for determining a compensator's thickness. An alternative method that is based on the Cunningham's modification of Clarkson's method to calculate scattered radiation in beams with an inhomogeneous cross-section is proposed. It is well known that the total dose distribution of radiotherapy photon beam consists of the contributions of the primary beam, attenuated by the tissue layer, and the scattered radiation generated by the primary radiation in single and multiple photon scatter events. The scattered component can be represented as a function of the primary radiation. The central point of our method is the numerical estimation of the primary distribution required to achieve the desired total distribution. Now using the calculated primary distribution, the shape of the modulator could be determined. In this way the contribution of the scattered component is validated in a more accurate way than using effective attenuation coefficients, which is a common practice. The method is verified in various clinical situations and compared with the standard method. The accuracy, although dependent on geometry, was improved by at least 2%. With more complex geometries there is an even higher gain in accuracy with our method when compared to the standard method

The Theory of Coherent Radiation by Intense Electron Beams

CERN Document Server

Buts, Vyacheslav A; Kurilko, V.I

2006-01-01

Spurred by the development of high-current, high-energy relativistic electron beams this books delves into the foundations of a device and geometry independent theoretical treatment of a large collection of interacting and radiating electron bunches. Part I deals with the basics of the radiation emission of a single charged particle, paying particular attention to the effect of radiation reaction and dwelling on the corresponding well-known paradoxes. Part II investigates the collective behaviour of a high-density electron bunch where both discrete and continous beam modelling is explored. Part III treats the application to modern systems while still keeping the treatment as general as possible. This book will be mandatory reading for anyone working on the foundations of modern devices such as free electron lasers, plasma accelerators, synchroton sources and other modern sources of bright, coherent radiation with high spectral density.

Ion beam induced luminescence of germano-silicate optical fiber preform

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Youngwoong; Han, Wontaek [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Markovic, Nikola; Jaksic, Milko [Ruder Boskovic Institute, Zagred (Croatia)

2014-05-15

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives.

Ion beam induced luminescence of germano-silicate optical fiber preform

International Nuclear Information System (INIS)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho; Kim, Youngwoong; Han, Wontaek; Markovic, Nikola; Jaksic, Milko

2014-01-01

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives

A new non intercepting beam size diagnostics using diffraction radiation from a Slit

International Nuclear Information System (INIS)

Castellano, M.

1996-09-01

A new non interpreting beam size diagnostic for high charge electron beams is presented. This diagnostics is based on the analysis of the angular distribution of the 'diffracted' transition radiation emitted by the beam when crossing a slit cut in metallic foil. It allows a resolution better then the radiation transverse formation zone. Numerical results based on the parameters of the TTF FEL beam are given as example

Seeing the invisible: direct visualization of therapeutic radiation beams using air scintillation.

Science.gov (United States)

Fahimian, Benjamin; Ceballos, Andrew; Türkcan, Silvan; Kapp, Daniel S; Pratx, Guillem

2014-01-01

To assess whether air scintillation produced during standard radiation treatments can be visualized and used to monitor a beam in a nonperturbing manner. Air scintillation is caused by the excitation of nitrogen gas by ionizing radiation. This weak emission occurs predominantly in the 300-430 nm range. An electron-multiplication charge-coupled device camera, outfitted with an f/0.95 lens, was used to capture air scintillation produced by kilovoltage photon beams and megavoltage electron beams used in radiation therapy. The treatment rooms were prepared to block background light and a short-pass filter was utilized to block light above 440 nm. Air scintillation from an orthovoltage unit (50 kVp, 30 mA) was visualized with a relatively short exposure time (10 s) and showed an inverse falloff (r(2) = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r(2) = 0.9998). As energy increased, the divergence of the electron beam decreased and the penumbra improved. By irradiating a transparent phantom, the authors also showed that Cherenkov luminescence did not interfere with the detection of air scintillation. In a final illustration of the capabilities of this new technique, the authors visualized air scintillation produced during a total skin irradiation treatment. Air scintillation can be measured to monitor a radiation beam in an inexpensive and nonperturbing manner. This physical phenomenon could be useful for dosimetry of therapeutic radiation beams or for online detection of gross errors during fractionated treatments.

Seeing the invisible: Direct visualization of therapeutic radiation beams using air scintillation

Energy Technology Data Exchange (ETDEWEB)

Fahimian, Benjamin; Türkcan, Silvan; Kapp, Daniel S.; Pratx, Guillem, E-mail: pratx@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305 (United States); Ceballos, Andrew [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

2014-01-15

Purpose: To assess whether air scintillation produced during standard radiation treatments can be visualized and used to monitor a beam in a nonperturbing manner. Methods: Air scintillation is caused by the excitation of nitrogen gas by ionizing radiation. This weak emission occurs predominantly in the 300–430 nm range. An electron-multiplication charge-coupled device camera, outfitted with an f/0.95 lens, was used to capture air scintillation produced by kilovoltage photon beams and megavoltage electron beams used in radiation therapy. The treatment rooms were prepared to block background light and a short-pass filter was utilized to block light above 440 nm. Results: Air scintillation from an orthovoltage unit (50 kVp, 30 mA) was visualized with a relatively short exposure time (10 s) and showed an inverse falloff (r{sup 2} = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r{sup 2} = 0.9998). As energy increased, the divergence of the electron beam decreased and the penumbra improved. By irradiating a transparent phantom, the authors also showed that Cherenkov luminescence did not interfere with the detection of air scintillation. In a final illustration of the capabilities of this new technique, the authors visualized air scintillation produced during a total skin irradiation treatment. Conclusions: Air scintillation can be measured to monitor a radiation beam in an inexpensive and nonperturbing manner. This physical phenomenon could be useful for dosimetry of therapeutic radiation beams or for online detection of gross errors during fractionated treatments.

Estimates for the probability of survival of electrons in passing through a radiator

International Nuclear Information System (INIS)

Loos, J.

1977-01-01

Some calculations on the survival of electrons passing through various radiator thicknesses are tabulated. The results of these calculations should serve as a guide for expected attenuation of electrons in the beam when various Pb radiators are inserted

Schemes of Superradiant Emission from Electron Beams and "Spin-Flip Emission of Radiation"

CERN Document Server

Gover, A

2005-01-01

A unified analysis for Superradiant emission from bunched electron beams in various kinds of radiation scheme is presented. Radiation schemes that can be described by the formulation include Pre-bunched FEL (PB-FEL), Coherent Synchrotron Radiation (CSR), Smith-Purcell Radiation, Cerenkov-Radiation, Transition-Radiation and more. The theory is based on mode excitation formulation - either discrete or continuous (the latter - in open structures). The discrete mode formulation permits simple evaluation of the spatially coherent power and spectral power of the source. These figures of merit of the radiation source are useful for characterizing and comparing the performance of different radiation schemes. When the bunched electron beam emits superradiantly, these parameters scale like the square of the number of electrons, orders of magnitude more than spontaneous emission. The formulation applies to emission from single electron bunches, periodically bunched beams, or emission from a finite number of bunches in a...

Proton-beam radiation therapy dosimetry standardization

International Nuclear Information System (INIS)

Gall, K.P.

1995-01-01

Beams of protons have been used for radiation therapy applications for over 40 years. In the last decade the number of facilities treating patients and the total number of patients being treated has begun go grow rapidly. Due to the limited and experimental nature of the early programs, dosimetry protocols tended to be locally defined. With the publication of the AAPM Task Group 20 report open-quotes Protocol for Dosimetry of Heavy Charged Particlesclose quotes and the open-quotes European Code of Practice for Proton-Beam Dosimetryclose quotes the practice of determining dose in proton-beam therapy was somewhat unified. The ICRU has also recently commissioned a report on recommendations for proton-beam dosimetry. There have been three main methods of determining proton dose; the Faraday cup technique, the ionization chamber technique, and the calorimeter technique. For practical reasons the ionization chamber technique has become the most widely used. However, due to large errors in basic parameters (e.g., W-value) is also has a large uncertainty for absolute dose. It has been proposed that the development of water calorimeter absorbed dose standards would reduce the uncertainty in absolute proton dose as well as the relative dose between megavoltage X-ray beams and proton beams. The advantages and disadvantages are discussed

Theoretical and experimental study of an energy-reinforced braking radiation photon beam

International Nuclear Information System (INIS)

Bertin, Pierre-Yves

1966-01-01

This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

An analysis of whistler mode radiation from a 100 mA electron beam

International Nuclear Information System (INIS)

Goerke, R.T.; Kellogg, P.J.; Monson, S.J.

1990-01-01

Observations of whistler mode radiation generated by 2-, 4-, and 8-keV electron beams with a current of 100 mA, are analyzed. The electron accelerator was carried to ionospheric heights by a Nike Black Brant V rocket (National Research Council of Canada NVB-06). The instability causing the whistler mode radiation is investigated. Spectral measurements (0.1-13.0 MHz), from a sweeping receiver located on the ejected forward payload, are used to determine the nature of the instability. The sweeping receiver was connected alternatively to an electric or a magnetic dipole antenna. Most of the whistler mode radiation detected was consistent with Cerenkov radiation. The radiation fields observed were too large (cB ∼ 0.1 μV/m Hz 1/2 ) to be explained by incoherent processes. If electrostatic bunching in the beam at the plasma frequency is responsible for the whistler radiation, there would be a correlation between the plasma frequency radiation, and the whistler mode radiation for electron beams that are fired toward the detector. The observed correlation is minimal. Hence no evidence was found to support the hypothesis that electrostatic bunching at the plasma frequency was responsible for the enhancement of the whistler mode radiation produced by the NVB-06 electron beam

Attenuation of radiation- and drug-induced conditioned taste aversions following area postrema lesions in the rat

International Nuclear Information System (INIS)

Rabin, B.M.; Hunt, W.A.; Lee, J.

1983-01-01

The effects of lesions of the area postrema on the acquisition of radiation- and drug-induced (histamine and lithium chloride) conditioned taste aversions were investigated. The results indicated that area postrema lesions caused a significant attenuation of the aversion produced by pairing a novel sucrose solution with radiation (100 rad) or drug injection. Further, the area postrema lesions produced a similar level of attenuation of the taste aversion in all three treatment conditions. The results are discussed in terms of the implications of this finding for defining the mechanisms by which exposure to ionizing radiation can lead to the acquisition of a conditioned taste aversion

Interlaboratory comparison of radiation-induced attenuation in optical fibers

International Nuclear Information System (INIS)

Friebele, E.J.; Lyons, P.B.; Blackburn, J.C.

1989-08-01

A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10 -9 to 10 1 s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs

Study of radiation detectors response in standard X, gamma and beta radiation standard beams

International Nuclear Information System (INIS)

Nonato, Fernanda Beatrice Conceicao

2010-01-01

The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams ( 37 Cs and 60 Co), and some of them were tested in beta radiation ( 90 Sr+ 9' 0Y e 204 Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

Design of a digital beam attenuation system for computed tomography: Part I. System design and simulation framework

International Nuclear Information System (INIS)

Szczykutowicz, Timothy P.; Mistretta, Charles A.

2013-01-01

Purpose: The purpose of this work is to introduce a new device that allows for patient-specific imaging-dose modulation in conventional and cone-beam CT. The device is called a digital beam attenuator (DBA). The DBA modulates an x-ray beam by varying the attenuation of a set of attenuating wedge filters across the fan angle. The ability to modulate the imaging dose across the fan beam represents another stride in the direction of personalized medicine. With the DBA, imaging dose can be tailored for a given patient anatomy, or even tailored to provide signal-to-noise ratio enhancement within a region of interest. This modulation enables decreases in: dose, scatter, detector dynamic range requirements, and noise nonuniformities. In addition to introducing the DBA, the simulation framework used to study the DBA under different configurations is presented. Finally, a detailed study on the choice of the material used to build the DBA is presented. Methods: To change the attenuator thickness, the authors propose to use an overlapping wedge design. In this design, for each wedge pair, one wedge is held stationary and another wedge is moved over the stationary wedge. The composite thickness of the two wedges changes as a function of the amount of overlap between the wedges. To validate the DBA concept and study design changes, a simulation environment was constructed. The environment allows for changes to system geometry, different source spectra, DBA wedge design modifications, and supports both voxelized and analytic phantom models. A study of all the elements from atomic number 1 to 92 were evaluated for use as DBA filter material. The amount of dynamic range and tube loading for each element were calculated for various DBA designs. Tube loading was calculated by comparing the attenuation of the DBA at its minimum attenuation position to a filtered non-DBA acquisition. Results: The design and parametrization of DBA implemented FFMCT has been introduced. A simulation

Verification of Radiation Isocenter on Linac Beam 6 MV using Computed Radiography

Science.gov (United States)

Irsal, Muhammad; Hidayanto, Eko; Sutanto, Heri

2017-06-01

Radiation isocenter is more important part of quality assurance for the linear accelerator (Linac) due to radiation isocenter is a main location in irradiation radiotherapy, isocenter can shift when the gantry and collimator rotation. In general, the radiation isocenter verification using a special film. This research was conducted radiation isocenter verification using computed radiography with digital image processing techniques. Image acquisition was done using the modalities of Linac 6 MV with star shot method is star-shaped beam due to rotation of the collimator, gantry and couch. Then do the delineation on each beam to determine the centroid and beam diameter. By the results of verification of radiation isocenter performed on collimator and the couch, it shows that the size diameter for rotational collimator is 0.632 mm and 0.458 mm for the couch. Based on AAPM report 40 about the size of the Linac radiation isocenter diameter used in this study is still in good condition and worth to be operated because the value of the radiation isocenter diameter is below 2 mm.

Verification of Radiation Isocenter on Linac Beam 6 MV using Computed Radiography

International Nuclear Information System (INIS)

Irsal, Muhammad; Hidayanto, Eko; Sutanto, Heri

2017-01-01

Radiation isocenter is more important part of quality assurance for the linear accelerator (Linac) due to radiation isocenter is a main location in irradiation radiotherapy, isocenter can shift when the gantry and collimator rotation. In general, the radiation isocenter verification using a special film. This research was conducted radiation isocenter verification using computed radiography with digital image processing techniques. Image acquisition was done using the modalities of Linac 6 MV with star shot method is star-shaped beam due to rotation of the collimator, gantry and couch. Then do the delineation on each beam to determine the centroid and beam diameter. By the results of verification of radiation isocenter performed on collimator and the couch, it shows that the size diameter for rotational collimator is 0.632 mm and 0.458 mm for the couch. Based on AAPM report 40 about the size of the Linac radiation isocenter diameter used in this study is still in good condition and worth to be operated because the value of the radiation isocenter diameter is below 2 mm. (paper)

Detailed mechanical design of the LIPAc beam dump radiological shielding

Energy Technology Data Exchange (ETDEWEB)

Nomen, Oriol, E-mail: onomen@irec.cat [IREC, Barcelona, Catalonia (Spain); CDEI-UPC, Barcelona, Catalonia (Spain); Martínez, José I.; Arranz, Fernando; Iglesias, Daniel; Barrera, Germán; Brañas, Beatriz [CIEMAT, Madrid (Spain); Ogando, Francisco [UNED, Madrid (Spain); Molla, Joaquín [CIEMAT, Madrid (Spain); Sanmartí, Manel [IREC, Barcelona, Catalonia (Spain)

2013-10-15

Highlights: ► Mechanical design of the IFMIF LIPAc beam dump shielding has been performed. ► Lead shutter design performed to shield radiation from beam dump when LIPAc is off. ► External loads, working and dismantling conditions, included as design constraints. -- Abstract: The LIPAc is a 9 MeV, D{sup +} linear prototype accelerator for the validation of the IFMIF accelerator design. The high intensity, 125 mA CW beam is stopped in a copper cone involving a high production of neutrons and gamma radiation and activation of its surface. The beam stopper is surrounded by a shielding to attenuate the resulting radiation so that dose rate values comply with the limits at the different zones of the installation. The shielding includes for that purpose polyethylene rings, water tanks and gray cast iron rings. A lead shutter has also been designed to shield the gamma radiation that comes through the beam tube when the linear accelerator is not in operation, in order to allow access inside the building for maintenance tasks. The present work summarizes the detailed mechanical design of the beam dump shielding and the lead shutter taking into account the design constraints, such as working conditions and other external loads, as well as including provisions for dismantling.

Wood fibre density measurement with 238 Pu radiation

International Nuclear Information System (INIS)

Barry, B.J.; Baker, D.B.

1996-01-01

The form of the curve of attenuation by wood fibre of the X radiation from 238 Pu has been determined. An exponential function containing a term second order in the areal density of the fibre described the curve accurately. The effect of scatter is negligible, even with an uncollimated radiation beam. (author). 18 refs., 1 tab., 6 figs

Cryopump behavior in the presence of beam or nuclear radiation

International Nuclear Information System (INIS)

Law, P.K.

1977-12-01

Cryocondensation pumping has been proposed to be the method of gas removal for neutral-beam refueled fusion reactors. A cryocondensation pumping unit has been constructed to test design concepts and compatibility with conditions under actual beam operation and nuclear radiation environment. Various operating parameters for this test pumping unit have been measured, including pumping speeds for various gases and beam desorption effects. An experiment has been planned at the Berkeley Research Reactor to measure the desorption effects of high energy neutrons and gamma radiation. A foil activation method has been devised to accurately assess the energy spectrum of this neutron source, which is expected to be comparable to that of the Tokamak Fusion Test Reactor

The technology and economics of treating waste water with electron beam radiation

International Nuclear Information System (INIS)

Cleland, M.R.

1976-01-01

The use of ionizing radiation from electron beam accelerators is considered in this paper for the disinfection of waste water. Combinations of radiation with oxygen, chlorine, heat and retention media are discussed as possible methods to reduce the dosage requirements and the treatment costs. The production of ozone by the irradiation of oxygen is also evaluated as an alternative method of using this form of energy. The capital and operating costs for large electron beam facilities are analyzed to show the favorable trends with rising power levels. Cost comparisons between conventional disinfection processes and two radiation processes are presented and discussed. The results of these cost analyses support the premise that electron beam radiation should be evaluated as a likely competitor to ozonation or carbon filtration for large sewage treatment plants. (author)

The technology and economics of treating waste water with electron beam radiation

International Nuclear Information System (INIS)

Cleland, M.R.

1976-01-01

The use of ionizing radiation from electron beam accelerators is considered in this paper for the disinfection of waste water. Combinations of radiation with oxygen, chlorine, heat and retention media are discussed as possible methods to reduce the dosage requirements and the treatment costs. The production of ozone by the irradiation of oxygen is also evaluated as an alternative method of using this form of energy. The capital and operating costs for large electron beam facilities are analyzed to show the favorable trends with rising power levels. Cost comparisons between 'conventional' disinfection processes and two radiation processes are presented and discussed. The results of these cost analyses support the premise that electron beam radiation should be evaluated as a likely competitor to ozonation or carbon filtration for large sewage treatment plants. (orig.) [de

Successful beam tests for ALICE Transition Radiation Detector

CERN Multimedia

2002-01-01

Another round of beam tests of prototypes for the Transition Radiation Detector (TRD) for ALICE has been completed and there are already some good results. Mass production of the components of the detector will start early next year.   Top view of the setup for the Transition Radiation Detector prototype tests at CERN.On the left, can be seen the full-scale TRD prototype together with four smaller versions. These are busy days for the TRD (Transition Radiation Detector) team of ALICE. Twenty people - mainly from Germany, but also from Russia and Japan - were working hard during the beam tests this autumn at CERN to assess the performance of their detector prototypes. Analysis of the data shows that the TRD can achieve the desired physics goal even for the highest conceivable multiplicities in lead-lead collisions at the LHC. In its final configuration in the ALICE experiment, the TRD will greatly help in identifying high-momentum electrons, which are 'needles in a haystack' that consists mostly of...

Radiation protection clothes in X-ray-diagnostics. Comparison of test methods

International Nuclear Information System (INIS)

Pichler, T.; Schoepf, T.; Ennemoser, O.

2009-01-01

For testing the attenuation of the protection clothes the standard EN 61331-1 for attenuation measurements in the ''narrow and broad beam'' is available as well as the DIN 6857-1 for determination of shielding properties in the so called ''inverse broad-beam geometry''. The attenuation measurements in the narrow beam don't consider scattered radiation and fluorescence due to the arrangement. This leads to the fact that the protective effect of lead-free-Materials will be miss-estimated when compared to lead. In this work the measurements of shielding properties in inverse broad-beam geometry according to the DIN 6857-1 were compared with attenuation measurements according to the EN 61331-1. Also the dependence of the chamber was studied. Attenuation measurements were performed with lead- and lead-free-materials. Additional certificated lead-foils with high purity and precise thickness of 0.1 to 2 mm were used. For measuring a cylinder chamber of 30 cm 3 and two flat chambers of 75 cm 3 (SFD) and 112 cm 3 (FC) were used. The measurements in inverse broad-beam geometry according to the DIN 6857-1 show adequate results, also in testing lead-free protection materials. The results in attenuation correspond to a large extent to those, which are determined by measurements in the broad beam. When performing measurements in inverse geometry however the characteristic of the used chamber is not negligible. (orig.)

Radiation optic neuropathy after external beam radiation therapy for acromegaly: report of two cases

International Nuclear Information System (INIS)

Bergh, Alfons C.M. van den; Hoving, Marjanke A.; Links, Thera P.; Dullaart, Robin P.F.; Ranchor, Adelita V.; Weeme, Cees A. ter; Canrinus, Alof A.; Szabo, Ben G.; Pott, Jan-Willem R.

2003-01-01

For diagnosing radiation optic neuropathy (RON) ophthalmological and imaging data were evaluated from 63 acromegalic patients, irradiated between 1967 and 1998. Two patients developed RON: one patient in one optic nerve 10 years and another patient in both optic nerves 5 months after radiation therapy. RON is a rare complication after external beam radiation therapy for acromegaly, which can occur after a considerable latency period

Stabilization of synchrotron radiation x-ray beam by MOSTAB

CERN Document Server

Kudo, T P; Tanida, H; Furukawa, Y; Hirono, T; Ishikawa, T; Nishino, Y

2003-01-01

Monochromator stabilization (MOSTAB) is a feedback control system to stabilize an x-ray beam of synchrotron radiation. It applies a feedback voltage to a piezo electric transducer attached to a double-crystal monochromator. We developed MOSTAB modules and examined their performances using SPring-8 beamlines. The x-ray beam position stabilization using MOSTAB was realized simultaneously with the x-ray beam intensity stabilization. As an example of its application, we performed EXAFS measurement with MOSTAB. (author)

Radiation conditions for computerized tomography: determination and comparison

International Nuclear Information System (INIS)

Andrade, Lucio das Chagas de

2016-01-01

Radiology is the practice in which radiation beams, usually radiation X are used to produce an image of the human body in order to obtain a diagnosis, for example, to evaluate a pathological condition by computerized tomography (CT). Although the computerized tomography diagnostic potential is unquestionable, caution must be taken because the doses are almost always higher than the observed in conventional radiology procedures. The ionization chamber used for dosimetry in CT is a unsealed cylindrical chamber with 10 cm and 15 cm of sensitive length. A typical characteristics of this camera is its uniform response to radiation incident at all angles around its axis. The revised edition of IEC 61267 (2005) brought as an innovation the radiation conditions for computed tomography, RQT, that simulate non-attenuated beam and are used in special CT applications. This study aims to establish the necessary conditions to obtain radiation pattern beam computed tomography, RQT, and a calibration laboratory implementation for pencil ionization chambers used in the beam dosimetry produced by these scanners in the Metrology National Laboratory of Ionizing Radiation (LNMRI). In the implementation of RQT conditions we were found that the ratio of kerma rates in the air, with or without additional filtration equivalent to the first HVL (half-value layer), are in accordance with IEC 61267 (2005), which provides a range between 48.5% and 51.5% for each quality. The LNMRI characterized the radiation conditions of RQT series (IEC, 2005), obtaining a percentage of 49.6% for the RQT 8, 50% for the RQT 9 and 50,4% for the RQT 10. With the substitution of the total additional filtration RQT qualities, composed by Al + Cu and by a total filtration composed by copper (Cu) only, it can be seen the emergence of a similar RQT quality named Quality Copper Tomography - QCT. The results of the calibration, the RQT and QCT qualities, had expanded uncertainties with a confidence level 95.45%, less

Betatron radiation based diagnostics for plasma wakefield accelerated electron beams at the SPARC-LAB test facility

Energy Technology Data Exchange (ETDEWEB)

Shpakov, V.; Anania, M.P.; Biagioni, A.; Chiadroni, E. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); Cianchi, A. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); “Tor Vergata” University, via della Ricerca Scientifica 1, 00133 Rome (Italy); Curcio, A. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); Dabagov, S. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); P.N. Lebedev Physical Institute RAS, Leninskiy Prospekt 53, 119991 Moscow (Russian Federation); NRNU “MEPhI”, Kashirskoe highway 31, 115409 Moscow (Russian Federation); Ferrario, M.; Filippi, F. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); Marocchino, A. [Dipartimento SBAI Universitá di Roma ‘La Sapienza’, via Antonio Scarpa 14/16, 00161 Rome (Italy); Paroli, B. [INFN - MI, via Celoria 16, 20133 Milan (Italy); Pompili, R. [INFN - LNF, via Enrico Fermi 40, 00044 Frascati (Italy); Rossi, A.R. [INFN - MI, via Celoria 16, 20133 Milan (Italy); Zigler, A. [Racah Institute of Physics Hebrew University of Jerusalem (Israel)

2016-09-01

Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC-LAB for such diagnostics tool, along with expected parameters of betatron radiation. - Highlights: • The betatron radiation parameters in SPARC-LAB wakefiled experiments were studied. • The differences with betatron radiation in other wake-field experiments were highlighted. • The solution for betatron radiation detection was investigated.

Betatron radiation based diagnostics for plasma wakefield accelerated electron beams at the SPARC-LAB test facility

International Nuclear Information System (INIS)

Shpakov, V.; Anania, M.P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Dabagov, S.; Ferrario, M.; Filippi, F.; Marocchino, A.; Paroli, B.; Pompili, R.; Rossi, A.R.; Zigler, A.

2016-01-01

Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC-LAB for such diagnostics tool, along with expected parameters of betatron radiation. - Highlights: • The betatron radiation parameters in SPARC-LAB wakefiled experiments were studied. • The differences with betatron radiation in other wake-field experiments were highlighted. • The solution for betatron radiation detection was investigated.

Measurement of microwave radiation from electron beam in the atmosphere

Energy Technology Data Exchange (ETDEWEB)

Ohta, I.S.; Akimune, H. [Faculty of Science and Engineering, Konan University, Kobe 658-8501 (Japan); Fukushima, M.; Ikeda, D. [Institute of Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Inome, Y. [Faculty of Science and Engineering, Konan University, Kobe 658-8501 (Japan); Matthews, J.N. [University of Utah, Salt Lake City, UT 4112-0830 (United States); Ogio, S. [Graduate School of Science, Osaka City University, Osaka 558-8585 (Japan); Sagawa, H. [Institute of Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Sako, T. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Yamamoto, T., E-mail: tokonatu@konan-u.ac.jp [Faculty of Science and Engineering, Konan University, Kobe 658-8501 (Japan)

2016-02-21

We report the use of an electron light source (ELS) located at the Telescope Array Observatory in Utah, USA, to measure the isotropic microwave radiation from air showers. To simulate extensive air showers, the ELS emits an electron beam into the atmosphere and a parabola antenna system for the satellite communication is used to measure the microwave radiation from the electron beam. Based on this measurement, an upper limit on the intensity of a 12.5 GHz microwave radiation at 0.5 m from a 10{sup 18} eV air shower was estimated to be 3.96×10{sup −16} W m{sup −2} Hz{sup −1} with a 95% confidence level.

Electron Beam Induced Radiation Damage of the Semiconductor Radiation Detector based on Silicon

International Nuclear Information System (INIS)

Kim, Han Soo; Kim, Yong Kyun; Park, Se Hwan; Haa, Jang Ho; Kang, Sang Mook; Chung, Chong Eun; Cho, Seung Yeon; Park, Ji Hyun; Yoon, Tae Hyung

2005-01-01

A Silicon Surface Barrier (SSB) semiconductor detector which is generally used to detect a charged particle such as an alpha particle was developed. The performance of the developed SSB semiconductor detector was measured with an I-V curve and an alpha spectrum. The response for an alpha particle was measured by Pu-238 sources. A SSB semiconductor detector was irradiated firstly at 30sec, at 30μA and secondly 40sec, 40μA with a 2MeV pulsed electron beam generator in KAERI. And the electron beam induced radiation damage of a homemade SSB detector and the commercially available PIN photodiode were investigated. An annealing effect of the damaged SSB and PIN diode detector were also investigated using a Rapid Thermal Annealing (RTA). This data may assist in designing the silicon based semiconductor radiation detector when it is operated in a high radiation field such as space or a nuclear power plant

Scattered radiation in fan beam imaging systems

International Nuclear Information System (INIS)

Johns, P.C.; Yaffe, M.

1982-01-01

Scatter-to-primary energy fluence ratios (S/P) have been studied for fan x-ray beams as used in CT scanners and slit projection radiography systems. The dependence of S/P on phantom diameter, distance from phantom to image receptor, and kilovoltage is presented. An empirical equation is given that predicts S/P over a wide range of fan beam imaging configurations. For CT body scans on a 4th-generation machine, S/P is approximately 5%. Scattered radiation can produce a significant cupping artefact in CT images which is similar to that due to beam hardening. When multiple slices are used in scanned slit radiography, they can be arranged such that the increase in S/P is negligible. Calculations of scatter-to-primary ratios for first order scattering showed that for fan beams the contribution of coherent scatter is comparable to or greater than that of incoherent first scatter

Edge plasma density reconstruction for fast monoenergetic lithium beam probing

International Nuclear Information System (INIS)

Sasaki, S.; Takamura, S.; Ueda, M.; Iguchi, H.; Fujita, J.; Kadota, K.

1993-01-01

Two different electron density reconstruction methods for 8-keV neutral lithium beam probing have been developed for the Compact Helical System (CHS). Density dependences on emission and ionization processes are included by using effective rate coefficients obtained from the collisional radiative model. Since the two methods differ in the way the local beam density in the plasma is determined, the methods have different applicable electron densities. The beam attenuation is calculated by iteration from the electron density profile in method I. In method II, the beam remainder at the observation point z is determined by integrating the Li I emission intensity from z toward the position of emission tail-off. At the emission tail-off, the fast lithium beam is completely attenuated. Selecting an appropriate method enables us to obtain edge electron density profile well inside the last closed flux surface for various ranges of plasma densities (10 12 --5x10 13 cm -3 ). The electron density profiles reconstructed by these two different methods are in good agreement with each other and are consistent with results from ruby laser Thomson scattering

Beam standardization of X radiation in computed tomography

International Nuclear Information System (INIS)

Maia, Ana F.; Caldas, Linda V.E.

2005-01-01

The ionization chamber used in dosimetric procedures in computed tomography beams (CT), is a cylindrical chamber, unsealed, with the sensitive length between 10 and 15 cm, named pencil ionization chamber. Because the doses involved in CT procedures are higher s than those in the procedures in radiology, it is very important to ensure the appropriate calibration of pencil ionization chambers and thus the accuracy of Dosimetric procedures. Recently, only the Calibration Laboratory, from Institute de Pesquisas Energeticas e Nucleares, had standards fields of conventional radiodiagnostic, but not arrived to include the energy range used in CT. In this work, will be shown the results obtained in standard field of radiodiagnostic - all qualities of radiodiagnostic of series RQR (direct beam) and RQA (attenuated beam) described in IEC 61267 norm - in an industrial X-ray equipment of the Calibration Laboratory. The recommended qualities for the calibration of TC chambers are the qualities RQA9 and RQR9. The other qualities will be used for calibration of other radiodiagnostic dosimeters and also for a larger study of the energy dependence of the pencil ionization chambers

The effect of electron beam radiations on testicular damage in mice, Mus musculus

International Nuclear Information System (INIS)

Vikram, S.; Nair, Vijay Mala Grover

2013-01-01

Adult male Swiss albino mice, Mus musculus (8-10 weeks old) weighing 28±2.5 gm were exposed to varying doses (2-12 Gy) of electron beam radiations and maintained in animal house at 26-28 C. The animals were sacrificed following 35 and 60 days following exposure to electron beam radiations. The LD-50 value, change in the weight and histological details of the testis, sperm count, sperm shape abnormalities and sperm motility were recorded. The data suggests that electron beam radiations is a potential inducer to cause reproductive system dysfunctions which probably may be responsible leading to infertility. (author)

Characteristics of liver tissue for attenuate the gamma radiation; Caracteristicas del tejido hepatico para atenuar la radiacion gamma

Energy Technology Data Exchange (ETDEWEB)

Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R. [Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

2005-07-01

It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of {sup 137} Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10{sup -3} to 10{sup -5} MeV and the measured coefficient was compared with the one calculated. (Author)

Towards a quantitative, measurement-based estimate of the uncertainty in photon mass attenuation coefficients at radiation therapy energies

Science.gov (United States)

Ali, E. S. M.; Spencer, B.; McEwen, M. R.; Rogers, D. W. O.

2015-02-01

In this study, a quantitative estimate is derived for the uncertainty in the XCOM photon mass attenuation coefficients in the energy range of interest to external beam radiation therapy—i.e. 100 keV (orthovoltage) to 25 MeV—using direct comparisons of experimental data against Monte Carlo models and theoretical XCOM data. Two independent datasets are used. The first dataset is from our recent transmission measurements and the corresponding EGSnrc calculations (Ali et al 2012 Med. Phys. 39 5990-6003) for 10-30 MV photon beams from the research linac at the National Research Council Canada. The attenuators are graphite and lead, with a total of 140 data points and an experimental uncertainty of ˜0.5% (k = 1). An optimum energy-independent cross section scaling factor that minimizes the discrepancies between measurements and calculations is used to deduce cross section uncertainty. The second dataset is from the aggregate of cross section measurements in the literature for graphite and lead (49 experiments, 288 data points). The dataset is compared to the sum of the XCOM data plus the IAEA photonuclear data. Again, an optimum energy-independent cross section scaling factor is used to deduce the cross section uncertainty. Using the average result from the two datasets, the energy-independent cross section uncertainty estimate is 0.5% (68% confidence) and 0.7% (95% confidence). The potential for energy-dependent errors is discussed. Photon cross section uncertainty is shown to be smaller than the current qualitative ‘envelope of uncertainty’ of the order of 1-2%, as given by Hubbell (1999 Phys. Med. Biol 44 R1-22).

Intraoperative electron beam radiation therapy (IOEBRT) for carcinoma of the exocrine pancreas

International Nuclear Information System (INIS)

Dobelbower, R.R. Jr.; Konski, A.A.; Merrick, H.W. III; Bronn, D.G.; Schifeling, D.; Kamen, C.

1991-01-01

The abdominal cavities of 50 patients were explored in a specially constructed intraoperative radiotherapy operating amphitheater at the Medical College of Ohio. Twenty-six patients were treated with intraoperative and postoperative precision high dose external beam therapy, 12 with intraoperative irradiation but no external beam therapy, and 12 with palliative surgery alone. All but two patients completed the postoperative external beam radiation therapy as initially prescribed. The median survival time for patients treated with palliative surgery alone was 4 months, and that for patients treated with intraoperative radiotherapy without external beam therapy was 3.5 months. Patients undergoing intraoperative irradiation and external beam radiation therapy had a median survival time of 10.5 months. Four patients died within 30 days of surgery and two patients died of gastrointestinal hemorrhage 5 months posttreatment

Charged particle beam monitoring by means of synchrotron radiation

International Nuclear Information System (INIS)

Panasyuk, V.S.; Anevskij, S.I.

1984-01-01

Optical methods for monitoring the number of accelerated electrons and electron energy by means of beam synchrotron radiation (SR) as well as peculiarities of SR characteristics of beams with a small radius of the orbit are considered. Optical methods for charged particle beam monitoring are shown to ensure operative and precise monitoring the number of particles and particle energy. SR sources with large axial dimensions of an electron beam have specific spectral angular and polarization characteristics. If electron angular distribution at deflection from the median plane is noticeably wider than angular distribution of SR of a certain electron, relative SR characteristics of these soUrces are calculated with high accuracy

2D beam hardening correction for micro-CT of immersed hard tissue

Science.gov (United States)

Davis, Graham; Mills, David

2016-10-01

Beam hardening artefacts arise in tomography and microtomography with polychromatic sources. Typically, specimens appear to be less dense in the center of reconstructions because as the path length through the specimen increases, so the X-ray spectrum is shifted towards higher energies due to the preferential absorption of low energy photons. Various approaches have been taken to reduce or correct for these artefacts. Pre-filtering the X-ray beam with a thin metal sheet will reduce soft energy X-rays and thus narrow the spectrum. Correction curves can be applied to the projections prior to reconstruction which transform measured attenuation with polychromatic radiation to predicted attenuation with monochromatic radiation. These correction curves can be manually selected, iteratively derived from reconstructions (this generally works where density is assumed to be constant) or derived from a priori information about the X-ray spectrum and specimen composition. For hard tissue specimens, the latter approach works well if the composition is reasonably homogeneous. In the case of an immersed or embedded specimen (e.g., tooth or bone) the relative proportions of mineral and "organic" (including medium and plastic container) species varies considerably for different ray paths and simple beam hardening correction does not give accurate results. By performing an initial reconstruction, the total path length through the container can be determined. By modelling the X-ray properties of the specimen, a 2D correction transform can then be created such that the predicted monochromatic attenuation can be derived as a function of both the measured polychromatic attenuation and the container path length.

A detector for localizing diverging beams of ionizing radiations

International Nuclear Information System (INIS)

Allemand, Robert.

1974-01-01

Description is given of a detector for localizing diverging radiation beams, adapted to provide the angular distribution of nuclear events. That detector comprises a casing filled with a fluid adapted to produce electric charges under radiations and provided with a front-side and a rear-side, means for generating an electric field at right angles to portions of parallel surfaces of revolution having in common an axis of revolution contained in the place of symmetry, and a plane unit for localizing electric charges mounted at the rear of said means, the initial portion of the beam being on the axis of revolution. This can be applied to X-ray diffraction and to neutron diffraction [fr

Radiation protection commissioning of neutron beam instruments at the OPAL research reactor

International Nuclear Information System (INIS)

Parkes, Alison; Saratsopoulos, John; Deura, Michael; Kenny, Pat

2008-01-01

The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20 MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

[Radiometers performance attenuation and data correction in long-term observation of total radiation and photosynthetically active radiation in typical forest ecosystems in China].

Science.gov (United States)

Zhu, Zhi-Lin; Sun, Xiao-Min; Yu, Gui-Rui; Wen, Xue-Fa; Zhang, Yi-Ping; Han, Shi-Jie; Yan, Jun-Hua; Wang, Hui-Min

2011-11-01

Based on the total radiation and photosynthetically active radiation (PAR) observations with net radiometer (CNR1) and quantum sensor (Li-190SB) in 4 ChinaFLUX forest sites (Changbaishan, Qianyanzhou, Dinghushan, and Xishuangbanna) in 2003-2008, this paper analyzed the uncertainties and the radiometers performance changes in long-term and continuous field observation. The results showed that the 98% accuracy of the total radiation measured with CNR1 (Q(cNR1)) could satisfy the technical criterion for the sites except Xishuangbanna where the Q(CNR1) was averagely about 7% lower than Q(CM11), the radiation measured with high accuracy pyranometer CM11. For most sites, though the temperature had definite effects on the performance of CNR1, the effects were still within the allowable range of the accuracy of the instrument. Besides temperature, the seasonal fog often occurred in tropical rain forests in Xishuangbanna also had effects on the performance of CNR1. Based on the long-term variations of PAR, especially its ratio to total radiation in the 4 sites, it was found that quantum sensor (Li-190SB) had obvious performance attenuation, with the mean annual attenuation rate being about 4%. To correct the observation error caused by Li-190SB, an attempt was made to give a post-correction of the PAR observations, which could basically eliminate the quantum sensor's performance attenuation due to long-term field measurement.

Method and apparatus to monitor a beam of ionizing radiation

Science.gov (United States)

Blackburn, Brandon W.; Chichester, David L.; Watson, Scott M.; Johnson, James T.; Kinlaw, Mathew T.

2015-06-02

Methods and apparatus to capture images of fluorescence generated by ionizing radiation and determine a position of a beam of ionizing radiation generating the fluorescence from the captured images. In one embodiment, the fluorescence is the result of ionization and recombination of nitrogen in air.

Beam size measurement at high radiation levels

International Nuclear Information System (INIS)

Decker, F.J.

1991-05-01

At the end of the Stanford Linear Accelerator the high energy electron and positron beams are quite small. Beam sizes below 100 μm (σ) as well as the transverse distribution, especially tails, have to be determined. Fluorescent screens observed by TV cameras provide a quick two-dimensional picture, which can be analyzed by digitization. For running the SLAC Linear Collider (SLC) with low backgrounds at the interaction point, collimators are installed at the end of the linac. This causes a high radiation level so that the nearby cameras die within two weeks and so-called ''radiation hard'' cameras within two months. Therefore an optical system has been built, which guides a 5 mm wide picture with a resolution of about 30 μm over a distance of 12 m to an accessible region. The overall resolution is limited by the screen thickness, optical diffraction and the line resolution of the camera. Vibration, chromatic effects or air fluctuations play a much less important role. The pictures are colored to get fast information about the beam current, size and tails. Beside the emittance, more information about the tail size and betatron phase is obtained by using four screens. This will help to develop tail compensation schemes to decrease the emittance growth in the linac at high currents. 4 refs., 2 figs

Echo-enabled tunable terahertz radiation generation with a laser-modulated relativistic electron beam

Directory of Open Access Journals (Sweden)

Zhen Wang

2014-09-01

Full Text Available A new scheme to generate narrow-band tunable terahertz (THz radiation using a variant of the echo-enabled harmonic generation is analyzed. We show that by using an energy chirped beam, THz density modulation in the beam phase space can be produced with two lasers having the same wavelength. This removes the need for an optical parametric amplifier system to provide a wavelength-tunable laser to vary the central frequency of the THz radiation. The practical feasibility and applications of this scheme are demonstrated numerically with a start-to-end simulation using the beam parameters at the Shanghai Deep Ultraviolet Free-Electron Laser facility (SDUV. The central frequency of the density modulation can be continuously tuned by either varying the chirp of the beam or the momentum compactions of the chicanes. The influence of nonlinear rf chirp and longitudinal space charge effect have also been studied in our article. The methods to generate the THz radiation in SDUV with the new scheme and the estimation of the radiation power are also discussed briefly.

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

Energy Technology Data Exchange (ETDEWEB)

Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2013-11-01

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

Calibration of a turbidity meter for making estimates of total suspended solids concentrations and beam attenuation coefficients in field experiments

Science.gov (United States)

Usry, J. W.; Whitlock, C. H.

1981-01-01

Management of water resources such as a reservoir requires using analytical models which describe such parameters as the suspended sediment field. To select or develop an appropriate model requires making many measurements to describe the distribution of this parameter in the water column. One potential method for making those measurements expeditiously is to measure light transmission or turbidity and relate that parameter to total suspended solids concentrations. An instrument which may be used for this purpose was calibrated by generating curves of transmission measurements plotted against measured values of total suspended solids concentrations and beam attenuation coefficients. Results of these experiments indicate that field measurements made with this instrument using curves generated in this study should correlate with total suspended solids concentrations and beam attenuation coefficients in the water column within 20 percent.

INFLUENCE OF INCUBATION TIME, GAMMA RAYS AND ELECTRON BEAM ON RADIATION RESISTANCE OF SOME SELECTED PATHOGENS

International Nuclear Information System (INIS)

EL-HIFNAWI, H.N.; EL-TABLAWY, S.Y.

2009-01-01

The effect of different growth phases on the radiation resistance, antibiotic susceptibility and pathogenicity of certain selected pathogens (Escherichia coli, Candida albicans and Staphylococcus aureus) was studied in mice. The obtained results showed that Escherichia coli was slightly more resistant to gamma radiation in 18 h than 24 h or 48 h but it was relatively more resistant to electron beam in 24 h and 48 h than 18 h. Candida albicans showed radiation resistance nearly the same in all incubation times in the case of gamma radiation while for electron beam, its radiation resistance was slightly more in 24 h and 48 h than in 18 h. On the other hand, Staphylococcus aureus recorded much more resistance to gamma radiation in the 48 h than in 24 h or 18 h whereas in the case of electron beam, it was slightly more resistant in 18 h than in 24 h and 48 h.The antibiotic susceptibility of Escherichia coli reported that the exposure to gamma radiation at 3 kGy and electron beam at 6 kGy increase the susceptibility to the nalidixic acid and nitrofurantoin. When Candida albicans was exposed to 3 kGy gamma radiation and 6 kGy electron beam, the same sensitivity to nystatin was observed in comparison with the unexposed one while the sensitivity of Staphylococcus aureus to some antibiotics (amoxicillin, nitrofurantoin and tetracycline) was decreased after exposure to gamma radiation at 0.75 and 2 kGy and electron beam at 6 kGy, but for other antibiotics (trimethoprim/ sulfamethoxazole), the sensitivity was increased at 6 kGy electron beam.The lethality percent recorded after the oral ingestion of the mice with the unexposed Escherichia coli and Candida albicans were 25% and 100%, respectively, and for 6 kGy exposure to electron beam was 0% . The cotaneous disease and abscesses caused by the intradermal injection of the mice with unexposed Staphylococcus aureus was 75% and for 6 kGy exposure to electron beam was 25%.

A beam radiation monitor based on CVD diamonds for SuperB

Science.gov (United States)

Cardarelli, R.; Di Ciaccio, A.

2013-08-01

Chemical Vapor Deposition (CVD) diamond particle detectors are in use in the CERN experiments at LHC and at particle accelerator laboratories in Europe, USA and Japan mainly as beam monitors. Nowadays it is considered a proven technology with a very fast signal read-out and a very high radiation tolerance suitable for measurements in high radiation environment zones i.e. near the accelerators beam pipes. The specific properties of CVD diamonds make them a prime candidate for measuring single particles as well as high-intensity particle cascades, for timing measurements on the sub-nanosecond scale and for beam protection systems in hostile environments. A single-crystalline CVD (scCVD) diamond sensor, read out with a new generation of fast and high transition frequency SiGe bipolar transistor amplifiers, has been tested for an application as radiation monitor to safeguard the silicon vertex tracker in the SuperB detector from excessive radiation damage, cumulative dose and instantaneous dose rates. Test results with 5.5 MeV alpha particles from a 241Am radioactive source and from electrons from a 90Sr radioactive source are presented in this paper.

Loss of Matrix Metalloproteinase-13 Attenuates Murine Radiation-Induced Pulmonary Fibrosis

International Nuclear Information System (INIS)

Flechsig, Paul; Hartenstein, Bettina; Teurich, Sybille; Dadrich, Monika; Hauser, Kai; Abdollahi, Amir; Groene, Hermann-Josef; Angel, Peter; Huber, Peter E.

2010-01-01

Purpose: Pulmonary fibrosis is a disorder of the lungs with limited treatment options. Matrix metalloproteinases (MMPs) constitute a family of proteases that degrade extracellular matrix with roles in fibrosis. Here we studied the role of MMP13 in a radiation-induced lung fibrosis model using a MMP13 knockout mouse. Methods and Materials: We investigated the role of MMP13 in lung fibrosis by investigating the effects of MMP13 deficiency in C57Bl/6 mice after 20-Gy thoracic irradiation (6-MV Linac). The morphologic results in histology were correlated with qualitative and quantitative results of volume computed tomography (VCT), magnetic resonance imaging (MRI), and clinical outcome. Results: We found that MMP13 deficient mice developed less pulmonary fibrosis than their wildtype counterparts, showed attenuated acute pulmonary inflammation (days after irradiation), and a reduction of inflammation during the later fibrogenic phase (5-6 months after irradiation). The reduced fibrosis in MMP13 deficient mice was evident in histology with reduced thickening of alveolar septi and reduced remodeling of the lung architecture in good correlation with reduced features of lung fibrosis in qualitative and quantitative VCT and MRI studies. The partial resistance of MMP13-deficient mice to fibrosis was associated with a tendency towards a prolonged mouse survival. Conclusions: Our data indicate that MMP13 has a role in the development of radiation-induced pulmonary fibrosis. Further, our findings suggest that MMP13 constitutes a potential drug target to attenuate radiation-induced lung fibrosis.

Cloud classification in a mediterranean location using radiation data and sky images

International Nuclear Information System (INIS)

Martinez-Chico, M.; Batlles, F.J.; Bosch, J.L.

2011-01-01

Knowledge regarding the solar radiation reaching the earth's surface and its geographical distribution is very important for the use of solar energy as a resource to produce electricity. Therefore, a proper assessment of available solar resource is particularly important to determine the placement and operation of solar thermal power plants. To perform this analysis correctly, it is necessary to determine the main factors influencing the radiation reaching the earth's surface, such as the earth's geometry, terrain, and atmospheric attenuation by gases, particles and clouds. Among these factors, it is important to emphasise the role of clouds as the main attenuating factor of radiation. Information about the amount and type of clouds present in the sky is therefore necessary to analyse both their attenuation levels and the prevalence of different sky conditions. Cloud cover is characterised according to attenuation levels, using the beam transmittance (k b , ratio of direct radiation incident on the surface to the extraterrestrial solar radiation) and hemispherical sky images. An analysis of the frequency and duration of each type of cloud cover blocking the sun's disk is also performed. Results show prevailing sky situations that make the studied area very suitable for the use of solar energy systems. -- Highlights: → Beam transmittance index k b have been used successfully to classify the cloud cover. → The proposed classification has been used to study a Mediterranean location in south-eastern Spain. → Percentage of cloudless/cloudy situations showed a good potential for solar energy applications in the studied area.

Study of Radiation Shielding Properties of selected Tropical Wood Species for X-rays in the 50-150 keV Range

Directory of Open Access Journals (Sweden)

S. Aggrey-Smith

2016-03-01

Full Text Available This paper compares the attenuation coefficients of 20 tropical hard wood species based on their linear and mass attenuation and half value layer (HVL properties for X-rays of energy 50–150 keV using a narrow collimated beam from a Cs-137 source. The narrow collimated beam method made corrections from multiple and small-angle scatterings of photons unnecessary. The attenuation depended on the chemical composition and densities of the wood species. The linear attenuation coefficients of wood species at 50–150 keV were highest for Pterygota macrocarpa (4.53 m−1 and lowest for Antiaris africana (1.24 m−1; the mass attenuation coefficient was highest for Triplochiton scleroxylon (17.62 m2/kg and lowest for Nesogordonia papaverifera (2.27 m2/kg.The HVL was highest for Antiaris africana (0.27 m and lowest for Pterygota macrocarpa (0.149 m. Pterygota macrocarpa of about 0.36 m thickness could serve as a more affordable radiation shielding material against secondary scatter and leakage radiations in place of lead, copper or concrete for low X-ray radiations up to 150 keV.

Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

International Nuclear Information System (INIS)

Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

2017-01-01

Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers. - Highlights: • Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. • Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. • However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. • Optical tweezers can trap, move and positioned micron size particles with subnanometer accuracy in three dimensions. • One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. • Acoustical tweezers overcome this limitation since the force scales as the field intensity divided by its propagation speed. • However, the feasibility of single beam acoustical tweezers was demonstrated only recently. • We propose a review of the strong similarities but also the specificities of acoustical

Modelling radiation fields of ion beams in tissue-like materials

International Nuclear Information System (INIS)

Burigo, Lucas Norberto

2014-01-01

Fast nuclei are ionizing radiation which can cause deleterious effects to irradiated cells. The modelling of the interactions of such ions with matter and the related effects are very important to physics, radiobiology, medicine and space science and technology. A powerful method to study the interactions of ionizing radiation with biological systems was developed in the field of microdosimetry. Microdosimetry spectra characterize the energy deposition to objects of cellular size, i.e., a few micrometers. In the present thesis the interaction of ions with tissue-like media was investigated using the Monte Carlo model for Heavy-Ion Therapy (MCHIT) developed at the Frankfurt Institute for Advanced Studies. MCHIT is a Geant4-based application intended to benchmark the physical models of Geant4 and investigate the physical properties of therapeutic ion beams. We have implemented new features in MCHIT in order to calculate microdosimetric quantities characterizing the radiation fields of accelerated nucleons and nuclei. The results of our Monte Carlo simulations were compared with recent experimental microdosimetry data. In addition to microdosimetry calculations with MCHIT, we also investigated the biological properties of ion beams, e.g. their relative biological effectiveness (RBE), by means of the modified Microdosimetric-Kinetic model (MKM). The MKM uses microdosimetry spectra in describing cell response to radiation. MCHIT+MKM allowed us to study the physical and biological properties of ion beams. The main results of the thesis are as follows: MCHIT is able to describe the spatial distribution of the physical dose in tissue-like media and microdosimetry spectra for ions with energies relevant to space research and ion-beam cancer therapy; MCHIT+MKM predicts a reduction of the biological effectiveness of ions propagating in extended medium due to nuclear fragmentation reactions; We predicted favourable biological dose-depth profiles for monoenergetic helium and

High-power beam-based coherently enhanced THz radiation source

Directory of Open Access Journals (Sweden)

Yuelin Li (李跃林

2008-08-01

Full Text Available We propose a compact Smith-Purcell radiation device that can potentially generate high average power THz radiation with high conversion efficiency. The source is based on a train of short electron bunches from an rf photoemission gun at an energy of a few MeV. Particle tracking simulation and analysis show that, with a beam current of 1 mA, it is feasible to generate hundreds of watts of narrow-band THz radiation at a repetition rate of 1 MHz.

LIPAc personnel protection system for realizing radiation licensing conditions on injector commissioning with deuteron beam

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Hiroki, E-mail: takahashi.hiroki@jaea.go.jp [IFMIF/EVEDA Accelerator Group, Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Narita, Takahiro; Kasugai, Atsushi [IFMIF/EVEDA Accelerator Group, Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Kojima, Toshiyuki [Gitec Co. Ltd., Hachinohe, Aomori (Japan); Marqueta, Alvaro; Nishiyama, Koichi [IFMIF/EVEDA Project Team, Rokkasho, Aomori (Japan); Sakaki, Hironao [Quantum Beam Science Center, JAEA, Kizu, Kyoto (Japan); Gobin, Raphael [Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA/Saclay, DSM/IRFU, Gif/Yvette (France)

2016-11-01

Highlights: • Personnel Protection System (PPS) is developed to adapt the radiation licensing. • PPS achieves the target performance to secure the personnel safety. • Pulse Duty Management System (PDMS) is developed to manage the beam-operation-time. • Satisfying performance of PDMS is confirmed by injector operation with H+ beam. • By the result of PPS and PDMS tests, the radiation license was successfully obtained. - Abstract: The performance validation of the Linear IFMIF Prototype Accelerator (LIPAc), up to the energy of 9 MeV deuteron beam with 125 mA continuous wave (CW), is planned in Rokkasho, Japan. There are three main phases of LIPAc performance validation: Injector commissioning, RFQ commissioning and LIPAc commissioning. Injector commissioning was started by H{sup +} and D{sup +} beam. To apply the radiation licensing for the Injector commissioning, the entering/leaving to/from accelerator vault should be under control, and access to the accelerator vault has to be prohibited for any person during the beam operation. The Personnel Protection System (PPS) was developed to adapt the radiation licensing conditions. The licensing requests that PPS must manage the accumulated D{sup +} current. So, to manage the overall D{sup +} beam time during injector operation, Pulse Duty Management System (PDMS) was developed as a configurable subsystem as part of the PPS. The PDMS was tested during H{sup +} beam (as simulated D{sup +}) operation, to confirm that it can handle the beam inhibit from Injector before the beam accumulation is above the threshold value specified in the radiation licensing condition. In this paper, the design and configuration of these systems and the result of the tests are presented.

Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

Directory of Open Access Journals (Sweden)

Kazuhisa Nakajima

2014-12-01

Full Text Available We present a new external-beam radiation therapy system using very-high-energy (VHE electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

Responses of diode detectors to radiation beams from teletherapy machines

International Nuclear Information System (INIS)

Malinda, Lora; Nasukha

2003-01-01

Responses of diode detectors to radiation beams from teletherapy machines. It has been carried out responses to two sets of diode detector by using the beams of teletherapy Co-60 and medical linear accelerator. Each set of consist of 8 diode detectors was irradiated by using gamma beams from teletherapy Co-60 machines and 6 MV and 10 MV foron beams from medical linear accelerator and 6.9.12.16. and 20 MeV electron beams from medical linear accelerator. The detectors were positioned on the phantom circularly and radially and electronic equilibrium condition for all type and energy beams. It was found that every detectors had own individual response and it is not to be uniformity, since the fluctuation in between 16.6 % to 30.9 %. All detectors responses are linear to gamma and foron beams, and also for energy above 6 MeV for electron beams. Nonlinearity response occurs for 6 MeV electron beam, it is probably from the assumption of electronic equilibrium

Scattered radiation from applicators in clinical electron beams.

NARCIS (Netherlands)

Battum, L.J. van; Zee, W. van der; Huizenga, H.

2003-01-01

In radiotherapy with high-energy (4-25 MeV) electron beams, scattered radiation from the electron applicator influences the dose distribution in the patient. In most currently available treatment planning systems for radiotherapy this component is not explicitly included and handled only by a slight

Intense diagnostic neutral beam development for ITER

International Nuclear Information System (INIS)

Rej, D.J.; Henins, I.; Fonck, R.J.; Kim, Y.J.

1992-01-01

For the next-generation, burning tokamak plasmas such as ITER, diagnostic neutral beams and beam spectroscopy will continue to be used to determine a variety of plasma parameters such as ion temperature, rotation, fluctuations, impurity content, current density profile, and confined alpha particle density and energy distribution. Present-day low-current, long-pulse beam technology will be unable to provide the required signal intensities because of higher beam attenuation and background bremsstrahlung radiation in these larger, higher-density plasmas. To address this problem, we are developing a short-pulse, intense diagnostic neutral beam. Protons or deuterons are accelerated using magnetic-insulated ion-diode technology, and neutralized in a transient gas cell. A prototype 25-kA, 100-kV, 1-μs accelerator is under construction at Los Alamos. Initial experiments will focus on ITER-related issues of beam energy distribution, current density, pulse length, divergence, propagation, impurity content, reproducibility, and maintenance

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.

Detection of coherent X-ray transition radiation and its application to beam diagnostics

International Nuclear Information System (INIS)

Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Li Qiang; Moran, M.J.; Bergstrom, J.C.; Caplan, H.S.; Silzer, R.M.; Skopik, D.M.; Rothbart, G.B.

1989-01-01

We investigate the use of coherent X-ray transition radiation to measure the energy of ultra-relativistic charged particles. This can be used for beam diagnostics for both high-repetition-rate and single-pulse, high-current accelerators. The research also has possible applications for the detection and identification of these particles. By selecting foil thickness and spacing, it is possible to design radiators whose angle of emission varies radically over a range of charged particle energies. We have constructed three coherent radiators and tested them at two accelerators using electron beam energies ranging from 50 to 228 MeV. Soft X-ray emission (1-3 keV) was emitted in a circularly symmetrical annulus with half-angle divergence of 2.5-9.0 mrad. The angle of peak emission was found to increase with electron-beam energy, in contrast to the incoherent case for which the angle of emission varies inversely with electron-beam energy. (orig.)

The Effect of Various Waste Materials' Contents on the Attenuation Level of Anti-Radiation Shielding Concrete.

Science.gov (United States)

Azeez, Ali Basheer; Mohammed, Kahtan S; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Sandu, Andrei Victor; Razak, Rafiza Abdul

2013-10-23

Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137 Cs and ⁶⁰Co radioactive elements with photon energies of 0.662 MeV for 137 Cs and two energy levels of 1.17 and 1.33 MeV for the ⁶⁰Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10 -3 for 137 Cs and 0.92 ± 1.57 × 10 -3 for ⁶⁰Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.

Attenuation and cross-attenuation in taste aversion learning in the rat: Studies with ionizing radiation, lithium chloride and ethanol

International Nuclear Information System (INIS)

Rabin, B.M.; Hunt, W.A.; Lee, J.

1988-01-01

The preexposure paradigm was utilized to evaluate the similarity of ionizing radiation, lithium chloride and ethanol as unconditioned stimuli for the acquisition of a conditioned taste aversion. Three unpaired preexposures to lithium chloride (3.0 mEq/kg, IP) blocked the acquisition of a taste aversion when a novel sucrose solution was paired with either the injection of the same dose of lithium chloride or exposure to ionizing radiation (100 rad). Similar pretreatment with radiation blocked the acquisition of a radiation-induced aversion, but had no effect on taste aversions produced by lithium chloride (3.0 or 1.5 mEq/kg). Preexposure to ethanol (4 g/kg, PO) disrupted the acquisition of an ethanol-induced taste aversion, but not radiation- or lithium chloride-induced aversions. In contrast, preexposure to either radiation or lithium chloride attenuated an ethanol-induced taste aversion in intact rats, but not in rats with lesions of the area postrema. The results are discussed in terms of relationships between these three unconditioned stimuli and in terms of implications of these results for understanding the nature of the proximal unconditioned stimulus in taste aversion learning

Theoretical study of the attenuation of a gaussian beam penetrating into a dielectric circular wave guide

International Nuclear Information System (INIS)

Crenn, J.P.

1981-07-01

It is proposed to draw up an approximate formula directly giving the attenuation of a gaussian beam penetrating into a superdimensioned dielectric circular wave guide. This formula is derived from optical laws, i.e. Fresnel's formulae of the reflexion of a wave on a dielectric to which a correcting term due to diffraction has been added. The results given by this formula are compared with the existing results, based on the breakdown of a gaussian beam into propagation modes, thereby enabling their validity and the field of use to be checked. An application is then made to the wave guides that will be employed in the infrared interferometer fitted in JET [fr

Radiation degradation of marine polysaccharides by low energy electron beam

International Nuclear Information System (INIS)

Yoshii, Fumio; Nagasawa, Naotsugu; Kume, Tamikazu

2003-01-01

The radiation degradations of marine polysaccharides by both gamma Co-60 and electron beam irradiations are investigated. Polysaccharides and oligosaccharides can be produced by degradation of corresponding polysaccharides including marine polysaccharides such as alginates, chitin chitosan and carrageenan. The viscosity of alginate, chitosan and carrageenan solution decreases markedly with increase of the low energy electron beam irradiation time and the beam current. Furthermore, the viscosity is reduced sharply in short time for polysaccharide solution with low concentration, for instance carrageenan solution of 1%. (author)

POWER BEAMING LEAKAGE RADIATION AS A SETI OBSERVABLE

Energy Technology Data Exchange (ETDEWEB)

Benford, James N. [Microwave Sciences, 1041 Los Arabis Lane, Lafayette, CA 94549 (United States); Benford, Dominic J., E-mail: jimbenford@gmail.com [NASA’s Goddard Space Flight Center, Observational Cosmology Laboratory, Greenbelt, MD 20771 (United States)

2016-07-10

The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors, and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show that most power beaming applications commensurate with those suggested for our solar system would be detectable if using the frequency range monitored by the ATA, and so the lack of detection is a meaningful, if modest, constraint on extraterrestrial power beaming in that system. Until more extensive observations are made, the limited observation time and frequency coverage are not sufficiently broad in frequency and duration to produce firm conclusions. Such beams would be visible over large interstellar distances. This implies a new approach to the SETI search: instead of focusing on narrowband beacon transmissions generated by another civilization, look for more powerful beams with much wider bandwidth. This requires a new approach for their discovery by telescopes on Earth. Further studies of power beaming applications should be performed, potentially broadening the parameter space of the observable features that we have discussed here.

Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

Science.gov (United States)

Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

2017-07-01

Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers.

Visible-light beam size monitors using synchrotron radiation at CESR

Energy Technology Data Exchange (ETDEWEB)

Wang, S.T., E-mail: sw565@cornell.edu [Cornell Laboratory for Accelerator-Based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Rubin, D.L.; Conway, J.; Palmer, M.; Hartill, D. [Cornell Laboratory for Accelerator-Based Science and Education, Cornell University, Ithaca, NY 14853 (United States); Campbell, R.; Holtzapple, R. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States)

2013-03-01

A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 μm can be measured with a resolution of approximately 5 μm. To measure larger beam size (>500 μm), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the π-polarized component of SR, a small vertical beam size (∼70 μm) was measured during an undulator test run in CESR, which was consistent with the interferometer measurement. To measure the bunch length, a beam splitter is inserted to direct a fraction of light into a streak camera setup. This beam size monitor measures the transverse and longitudinal beam sizes simultaneously, which is successfully used for intrabeam scattering studies. Detailed error analysis is discussed.

Acoustical radiation torque and force for spheres and Bessel beam extinction efficiency

Science.gov (United States)

Marston, Philip L.; Zhang, Likun

2014-11-01

The scattering of optical and acoustical beams is relevant to the levitation and manipulation of drops. Here we examine theoretical developments in the acoustical case. We previously showed how the optical theorem for extinction can be extended to invariant beams. The example of a sphere in a Bessel beam facilitates the direct comparison with a circular disc computed using Babinet's principle and the Kirchhoff approximation. In related work, by considering traveling or standing wave first-order vortex beams we previously showed that the radiation torque is the ratio of the absorbed power and the radian acoustic frequency. By modifying the scattering to account for the viscosity of the surrounding fluid in the analysis of the absorbed power, approximations for radiation torque and force are obtained at long wavelengths in special cases and these can be compared with results published elsewhere.

Concept of a tunable source of coherent THz radiation driven by a plasma modulated electron beam

Science.gov (United States)

Zhang, H.; Konoplev, I. V.; Doucas, G.; Smith, J.

2018-04-01

We have carried out numerical studies which consider the modulation of a picosecond long relativistic electron beam in a plasma channel and the generation of a micro-bunched train. The subsequent propagation of the micro-bunched beam in the vacuum area was also investigated. The same numerical model was then used to simulate the radiation arising from the interaction of the micro-bunched beam with a metallic grating. The dependence of the radiation spectrum on the parameters of the micro-bunched beam has been studied and the tunability of the radiation by the variation of the micro-bunch spacing has been demonstrated. The micro-bunch spacing can be changed easily by altering the plasma density without changing the beam energy or current. Using the results of these studies, we develop a conceptual design of a tunable source of coherent terahertz (THz) radiation driven by a plasma modulated beam. Such a source would be a potential and useful alternative to conventional vacuum THz tubes and THz free-electron laser sources.

Summary Report of Working Group 5: Beam and Radiation Generation, Monitoring, and Control

International Nuclear Information System (INIS)

Church, Mike; Kim, Kiyong

2010-01-01

This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

Schistosoma mansoni: migration potential of normal and radiation attenuated parasites in naive guinea pigs

International Nuclear Information System (INIS)

Kamiya, H.; McLaren, D.J.

1987-01-01

Compressed tissue autoradiography using [75Se]selenomethionine labelled parasites has been used to investigate the migration potential of normal and radiation attenuated cercariae of Schistosoma mansoni in naive guinea pigs. By Day 14 after infection. 44% of normal parasites were detected as reduced silver foci in the liver; this value corresponded well with the number of liver parasites recovered by retrograde perfusion of the hepatic portal system on Day 42 (42% of the challenge). In contrast, cercariae subjected to 50 krad of gamma irradiation failed to migrate out of the skin. The migration capacity of 20 krad irradiated parasites was less severely affected in that about half of the challenge parasites reached the lungs, but virtually none moved to the liver. These data are discussed in relation to the kinetics of immunity induced in guinea pigs by infection or vaccination with normal or radiation attenuated parasites

Electron beam radiation effects on recycled polyamide-6

International Nuclear Information System (INIS)

Evora, Maria Cecilia; Silva, Leonardo G. de Andrade e

2001-01-01

Applications of electron beam processing in the treatment of polymers are commonly used. The interaction of high energy radiation with polymers may cause permanent modifications in the polymer's physicochemical structure. The induced modifications may result in degradation of the polymer or in improvement of its properties (crosslinking), which are simultaneous and competing processes, depending on the radiation dose utilized. Crosslinking occurs more readily in the polymer's amorphous content and this process makes the glass transition temperature (Tg) of the polymers to increase. Successive recycling cycles promote changes in polymers properties, such as breaking of structure, molecular weight reduction, melt index increase and mechanical resistance reduction. The polyamide-6 resin was recycled for three successive recycling cycles and thi polyamide-6 specimens were molded by the process of injection molding. These specimens were irradiated at the Nuclear Energetic Research Institute (IPEN) radiation facility, on a JOB 188 model accelerator, with a 1.5 MeV electron beam, doses of 200, 300, 400, 500 and 600 kGy, and dose rate of 22.61 kGy/s. The DMA tests were performed using DMA-983 equipment from TA Instruments and two heatings were adopted in order to eliminate the moisture absorption. The X-ray diffraction analysis wa carried out at the Philips PW 1830 model equipment

Transverse velocity modulator and generator schemes based on non-collinear radiation and electron beams

CERN Document Server

Varfolomeev, A A

2000-01-01

New non-collinear schemes are suggested for transverse velocity modulation of electron beams and for the generation of coherent spontaneous radiation by these transversely modulated beams. It is shown that due to the non-collinearity some orders of magnitude enhancement can be achieved for the coherent spontaneous radiation (CSR) power at both the fundamental and harmonic frequencies.

High-brightness electron beams for production of high intensity, coherent radiation for scientific and industrial applications

International Nuclear Information System (INIS)

Kim, K.-J.

1999-01-01

Relativistic electron beams with high six-dimensional phase space densities, i.e., high-brightness beams, are the basis for efficient generation of intense and coherent radiation beams for advanced scientific and industrial applications. The remarkable progress in synchrotrons radiation facilities from the first generation to the current, third-generation capability illustrates this point. With the recent development of the high-brightness electron gun based on laser-driven rf photocathodes, linacs have become another important option for high-brightness electron beams. With linacs of about 100 MeV, megawatt-class infrared free-electron lasers can be designed for industrial applications such as power beaming. With linacs of about 10 GeV, 1- angstrom x-ray beams with brightness and time resolution exceeding by several orders of magnitude the current synchrotrons radiation sources can be generated based on self-amplified spontaneous emission. Scattering of a high-brightness electron beam by high power laser beams is emerging as a compact method of generating short-pulse, bright x-rays. In the high-energy frontier, photons of TeV quantum energy could be generated by scattering laser beams with TeV electron beams in future linear colliders

Observation of coherent Smith-Purcell and transition radiation driven by single bunch and micro-bunched electron beams

Science.gov (United States)

Liang, Yifan; Du, Yingchao; Su, Xiaolu; Wang, Dan; Yan, Lixin; Tian, Qili; Zhou, Zheng; Wang, Dong; Huang, Wenhui; Gai, Wei; Tang, Chuanxiang; Konoplev, I. V.; Zhang, H.; Doucas, G.

2018-01-01

Generation of coherent Smith-Purcell (cSPr) and transition/diffraction radiation using a single bunch or a pre-modulated relativistic electron beam is one of the growing research areas aiming at the development of radiation sources and beam diagnostics for accelerators. We report the results of comparative experimental studies of terahertz radiation generation by an electron bunch and micro-bunched electron beams and the spectral properties of the coherent transition and SP radiation. The properties of cSPr spectra are investigated and discussed, and excitations of the fundamental and second harmonics of cSPr and their dependence on the beam-grating separation are shown. The experimental and theoretical results are compared, and good agreement is demonstrated.

Attenuation of a radiation-induced conditioned taste aversion after the development of ethanol tolerance

International Nuclear Information System (INIS)

Hunt, W.A.; Rabin, B.M.

1988-01-01

An attempt to reduce a radiation-induced conditioned taste aversion (CTA) was undertaken by rendering animals tolerant to ethanol. Ethanol tolerance, developed over 5 days, was sufficient to block a radiation-induced taste aversion, as well as an ethanol-induced CTA. Several intermittent doses of ethanol, which did not induce tolerance but removed the novelty of the conditioning stimulus, blocked an ethanol-induced CTA but not the radiation-induced CTA. A CTA induced by doses of radiation up to 500 rads was attenuated. These data suggest that radioprotection developing in association with ethanol tolerance is a result of a physiological response to the chronic presence of ethanol not to the ethanol itself

Intensity-Modulated Radiation Therapy with Noncoplanar Beams for Treatment of Prostate Cancer in Patients with Bilateral Hip Prosthesis-A Case Study

International Nuclear Information System (INIS)

Brooks, Chris; Cheung, Rex Min; Kudchadker, Rajat J.

2010-01-01

Megavoltage photon intensity-modulated radiation therapy (IMRT) is typically used in the treatment of prostate cancer at our institution. Approximately 1% to 2% of patients with prostate cancer have hip prostheses. The presence of the prosthesis usually complicates the planning process because of dose perturbation around the prosthesis, radiation attenuation through the prosthesis, and the introduction of computed tomography artifacts in the planning volume. In addition, hip prostheses are typically made of materials of high atomic number, which add uncertainty to the dosimetry of the prostate and critical organs in the planning volume. When the prosthesis is bilateral, treatment planning is further complicated because only a limited number of beam angles can be used to avoid the prostheses. In this case study, we will report the observed advantages of using noncoplanar beams in the delivery of IMRT to a prostate cancer patient with bilateral hip prostheses. The treatment was planned for 75.6 Gy using a 7-field coplanar approach and a noncoplanar arrangement, with all fields avoiding entrance though the prostheses. Our results indicate that, compared with the coplanar plan, the noncoplanar plan delivers the prescribed dose to the target with a slightly better conformality and sparing of rectal tissue versus the coplanar plan.

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

The Effect of Various Waste Materials’ Contents on the Attenuation Level of Anti-Radiation Shielding Concrete

Science.gov (United States)

Azeez, Ali Basheer; Mohammed, Kahtan S.; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Sandu, Andrei Victor; Razak, Rafiza Abdul

2013-01-01

Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662 MeV for 137Cs and two energy levels of 1.17 and 1.33 MeV for the 60Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10−3 for 137Cs and 0.92 ± 1.57 × 10−3 for 60Co. Substantial improvement in attenuation performance by 20%–25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%–30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities. PMID:28788363

The evaluation of properties for radiation therapy techniques with flattening filter-free beam and usefulness of time and economy to a patient with the radiation therapy

International Nuclear Information System (INIS)

Goo, Jang Hyeon; Won, Hui Su; Hong, Joo Wan; Chang, Nam Jun; Park, Jin Hong

2014-01-01

The aim of this study was to appraise properties for radiation therapy techniques and effectiveness of time and economy to a patient in the case of applying flattening filter-free (3F) and flattening filter (2F) beam to the radiation therapy. Alderson rando phantom was scanned for computed tomography image. Treatment plans for intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and stereotactic body radiation therapy (SBRT) with 3F and 2F beam were designed for prostate cancer. To evaluate the differences between the 3F and 2F beam, total monitor units (MUs), beam on time (BOT) and gantry rotation time (GRT) were used and measured with TrueBeam TM STx and Surveillance And Measurement (SAM) 940 detector was used for photoneutron emitted by using 3F and 2F. To assess temporal and economical aspect for a patient, total treatment periods and medical fees were estimated. In using 3F beam, total MUs in IMRT plan increased the highest up to 34.0% and in the test of BOT, GRT and photoneutron, the values in SBRT plan decreased the lowest 39.8, 38.6 and 48.1%, respectively. In the temporal and economical aspect, there were no differences between 3F and 2F beam in all of plans and the results showed that 10 days and 169,560 won was lowest in SBRT plan. According as the results, total MUs increased by using 3F beam than 2F beam but BOT, GRT and photoneutron decreased. From above the results, using 3F beam can decrease intra-fraction setup error and risk of radiation-induced secondary malignancy. But, using 3F beam did not make the benefits of temporal and economical aspect for a patient with the radiation therapy

The evaluation of properties for radiation therapy techniques with flattening filter-free beam and usefulness of time and economy to a patient with the radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Goo, Jang Hyeon; Won, Hui Su; Hong, Joo Wan; Chang, Nam Jun; Park, Jin Hong [Dept. of Radiation Oncology, Seoul national university Bundang hospital, Sungnam (Korea, Republic of)

2014-12-15

The aim of this study was to appraise properties for radiation therapy techniques and effectiveness of time and economy to a patient in the case of applying flattening filter-free (3F) and flattening filter (2F) beam to the radiation therapy. Alderson rando phantom was scanned for computed tomography image. Treatment plans for intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and stereotactic body radiation therapy (SBRT) with 3F and 2F beam were designed for prostate cancer. To evaluate the differences between the 3F and 2F beam, total monitor units (MUs), beam on time (BOT) and gantry rotation time (GRT) were used and measured with TrueBeam{sup TM} STx and Surveillance And Measurement (SAM) 940 detector was used for photoneutron emitted by using 3F and 2F. To assess temporal and economical aspect for a patient, total treatment periods and medical fees were estimated. In using 3F beam, total MUs in IMRT plan increased the highest up to 34.0% and in the test of BOT, GRT and photoneutron, the values in SBRT plan decreased the lowest 39.8, 38.6 and 48.1%, respectively. In the temporal and economical aspect, there were no differences between 3F and 2F beam in all of plans and the results showed that 10 days and 169,560 won was lowest in SBRT plan. According as the results, total MUs increased by using 3F beam than 2F beam but BOT, GRT and photoneutron decreased. From above the results, using 3F beam can decrease intra-fraction setup error and risk of radiation-induced secondary malignancy. But, using 3F beam did not make the benefits of temporal and economical aspect for a patient with the radiation therapy.

Attenuate Eimeria Tenella parasite by gamma radiation in chicken vaccination

International Nuclear Information System (INIS)

El-atar, M.A.

1998-01-01

Mature occysts of eimeria tenella were attenuated by different doses of gamma radiation. The vitality, pathogenicity and immunogenicity of these occysts were examined by infecting one day old broiler chicks. The study revealed that the irradiated occysts lost pathogenicity by increasing radiation dose. To examine the immunogenicity of irradiated occysts, chickens were challenged 28 days post immunogenic infection. It was shown that the irradiated occycts kept their immunogenicity but this ability decreased when the irradiation dose was increased. Also, the number of vaccination doses as well as the level of irradiation were studied. Occysts irradiated with 15, 18, 20 Krad were used to vaccinate one-day old broiler chicks for one or two times, and seven-day old chicks for three times. High level of protection was observed as shown by disappeaeance of clinical signs or mortality in most vaccinated groups

A proposal for PET/MRI attenuation correction with μ-values measured using a fixed-position radiation source and MRI segmentation

Energy Technology Data Exchange (ETDEWEB)

Kawaguchi, Hiroshi, E-mail: kwgc@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Hirano, Yoshiyuki, E-mail: yhirano@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yoshida, Eiji, E-mail: rush@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kershaw, Jeff, E-mail: len@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shiraishi, Takahiro, E-mail: tshira@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Suga, Mikio, E-mail: mikio.suga@faculty.chiba-u.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Engineering of Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Ikoma, Yoko, E-mail: ikoma@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Obata, Takayuki, E-mail: t_obata@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ito, Hiroshi, E-mail: hito@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yamaya, Taiga, E-mail: taiga@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2014-01-11

Several MRI-based attenuation correction methods have been reported for PET/MRI; these methods are expected to make efficient use of high-quality anatomical MRIs and reduce the radiation dose for PET/MRI scanning. The accuracy of the attenuation map (μ-map) from an MRI depends on the accuracy of tissue segmentation and the attenuation coefficients to be assigned (μ-values). In this study, we proposed an MRI-based μ-value estimation method with a non-rotational radiation source to construct a suitable μ-map for PET/MRI. The proposed method uses an accurately segmented tissue map, the partial path length of each tissue, and detected intensities of attenuated radiation from a fixed-position (rather than a rotating) radiation source to obtain the μ-map. We estimated the partial path length from a virtual blank scan of fixed-point radiation with the same scanner geometry using the known tissue map from MRI. The μ-values of every tissue were estimated by inverting a linear relationship involving the partial path lengths and measured radioactivity intensity. Validation of the proposed method was performed by calculating a fixed- point data set based upon real a real transmission scan. The root-mean-square error between the μ-values derived from a conventional transmission scan and those obtained with our proposed method were 2.4±1.4%, 17.4±9.1% and 6.6±4.3% for brain, bone and soft tissue other than brain, respectively. Although the error estimates for bone and soft tissue are not insignificant, the method we propose is able to estimate the brain μ-value accurately and it is this factor that most strongly affects the quantitative value of PET images because of the large volumetric ratio of the brain. -- Highlights: • An MRI-derived µ-map for the attenuation correction of PET images is proposed. • Method relies on segmentation of MRI and a fixed-point source transmission scan. • Tissue segmentation reduces the number of unknown µ-values. • Method

A proposal for PET/MRI attenuation correction with μ-values measured using a fixed-position radiation source and MRI segmentation

International Nuclear Information System (INIS)

Kawaguchi, Hiroshi; Hirano, Yoshiyuki; Yoshida, Eiji; Kershaw, Jeff; Shiraishi, Takahiro; Suga, Mikio; Ikoma, Yoko; Obata, Takayuki; Ito, Hiroshi; Yamaya, Taiga

2014-01-01

Several MRI-based attenuation correction methods have been reported for PET/MRI; these methods are expected to make efficient use of high-quality anatomical MRIs and reduce the radiation dose for PET/MRI scanning. The accuracy of the attenuation map (μ-map) from an MRI depends on the accuracy of tissue segmentation and the attenuation coefficients to be assigned (μ-values). In this study, we proposed an MRI-based μ-value estimation method with a non-rotational radiation source to construct a suitable μ-map for PET/MRI. The proposed method uses an accurately segmented tissue map, the partial path length of each tissue, and detected intensities of attenuated radiation from a fixed-position (rather than a rotating) radiation source to obtain the μ-map. We estimated the partial path length from a virtual blank scan of fixed-point radiation with the same scanner geometry using the known tissue map from MRI. The μ-values of every tissue were estimated by inverting a linear relationship involving the partial path lengths and measured radioactivity intensity. Validation of the proposed method was performed by calculating a fixed- point data set based upon real a real transmission scan. The root-mean-square error between the μ-values derived from a conventional transmission scan and those obtained with our proposed method were 2.4±1.4%, 17.4±9.1% and 6.6±4.3% for brain, bone and soft tissue other than brain, respectively. Although the error estimates for bone and soft tissue are not insignificant, the method we propose is able to estimate the brain μ-value accurately and it is this factor that most strongly affects the quantitative value of PET images because of the large volumetric ratio of the brain. -- Highlights: • An MRI-derived µ-map for the attenuation correction of PET images is proposed. • Method relies on segmentation of MRI and a fixed-point source transmission scan. • Tissue segmentation reduces the number of unknown µ-values. • Method

Determination of particles concentration in Black Sea waters from spectral beam attenuation coefficient

Science.gov (United States)

Korchemkina, E. N.; Latushkin, A. A.; Lee, M. E.

2017-11-01

The methods of determination of concentration and scattering by suspended particles in seawater are compared. The methods considered include gravimetric measurements of the mass concentration of suspended matter, empirical and analytical calculations based on measurements of the light beam attenuation coefficient (BAC) in 4 spectral bands, calculation of backscattering by particles using satellite measurements in the visible spectral range. The data were obtained in two cruises of the R/V "Professor Vodyanitsky" in the deep-water part of the Black Sea in July and October 2016., Spatial distribution of scattering by marine particles according to satellite data is in good agreement with the contact measurements.

Radiation beans characterization and implantation for study of lead equivalent individual protection device used in radiodiagnostic practices

International Nuclear Information System (INIS)

Pereira, Leslie Silva

2004-01-01

The protective shielding (IPC) must be used by occupationally exposed professionals, patients and volunteers, in order to optimize the doses who receive due to radiological practices. International and national norms establish the methodology to be adopted for determination of the IPC attenuation. In this work, the IPC had been submitted to X-rays beams with known characteristics, standardized for determination of their attenuation equivalent thickness by comparison to an experimental lead attenuation slope. This comparison technique allowed insurance estimative of the IPC attenuation equivalent thickness in mm of lead. Thus, it was possible to verify the conformity of the attenuation equivalent thickness determined experimentally and the value of the thickness indicated by the manufacturer. To carry out this work, it was necessary the implementation of experimental setups stated in the specifics norms, the study of the X-rays beams original features and the determination of combined additional filters, in order to allow the X-ray equipment used operates in compliance with Norm IEC 61331-1 IEC. The radiation quality selected is characterized by a 100 kV voltage and a 0.25 mm of copper overall filtration. The implementation of this radiation quality it was carried through of its first and second HVL (Half Value Layer). Thus, a methodology according to the international Norms has been implemented in the laboratory. The results of the present work provide suitable and useful information about radiation beams features related to the determination techniques of the attenuation properties. Once implemented the procedures for conformity evaluation of the protection devices, it will be possible to carry out specific quality control tests, which will be helpful to manufacturers, customers, as well as authorities in the radiological protection and health areas. (author)

Observation of optical Smith-Purcell radiation at an electron beam energy of 855 MeV

International Nuclear Information System (INIS)

Kube, G.; Backe, H.; Euteneuer, H.; Grendel, A.; Hagenbuck, F.; Hartmann, H.; Kaiser, K.H.; Lauth, W.; Schoepe, H.; Wagner, G.; Walcher, Th.; Kretzschmar, M.

2002-01-01

Smith-Purcell radiation, generated when a beam of charged particles passes close to the surface of a diffraction grating, has been studied in the visible spectral range at wavelengths of 360 and 546 nm with the low emittance 855 MeV electron beam of the Mainz Microtron MAMI. The beam focused to a spot size of 4 μm (full width at half maximum) passed over optical diffraction gratings of echelle profiles with blaze angles of 0.8 deg., 17.27 deg., and 41.12 deg. and grating periods of 0.833 and 9.09 μm. Taking advantage of the specific emission characteristics of Smith-Purcell radiation a clear separation from background components, such as diffracted synchrotron radiation from upstream beam optical elements and transition radiation, was possible. The intensity scales with a modified Bessel function of the first kind as a function of the distance between electron beam and grating surface. Experimental radiation factors have been determined and compared with calculations on the basis of Van den Berg's theory [P.M. Van den Berg, J. Opt. Soc. Am. 63, 689 (1973)]. Fair agreement has been found for gratings with large blaze angles while the measurement with the shallow grating (blaze angle 0.8 deg.) is at variance with this theory. Finally, the optimal operational parameters of a Smith-Purcell radiation source in view of already existing powerful undulator sources are discussed

Coherent electromagnetic radiation of a modulated beam of charged particles

Energy Technology Data Exchange (ETDEWEB)

Pankratov, S G [The State Committee of Standards of the USSR, Moscow, USSR

1977-12-27

The intensity of electromagnetic radiation produced by a modulated beam of charged particles is estimated. The coherence effect is due to the modulation, i.e. to periodicity in the particles distribution.

Iron influence in self-attenuation of gamma radiation in sand samples

Energy Technology Data Exchange (ETDEWEB)

Aquino, Reginaldo R.; Cavalcante, Fernanda; Pecequilo, Brigitte R.S, E-mail: raquino@ipen.br, E-mail: fcavalcante@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

2013-07-01

Self-attenuation of gamma rays are usually observed in sand samples, due to the presence of iron particles of natural or anthropogenic causes, which may lead to misleading activities concentrations results. As iron atoms are often present in sand samples, the self-attenuation contribution from this mineral requires special attention when assessing sand samples radioactivity. This contributions in verified in the in the present study, using several silica (sand-like) samples doped with different concentrations of iron. The samples were arranged with pure SiO{sub 4} (98,9%) mineral from the region of Setiba, (Espirito Santo state, Brazil) and Itabirito mineral, from Itabira (Minas Gerais state, Brazil), using standard 100 mL high density polyethylene (HDPE) flat-botton cylindrical flasks, each sealed using a 52.5 mm plan screw cap and bubble spigot. Three samples were arranged in different concentrations - Fe 25% and SiO{sub 4} 75%; Fe 50% and SiO{sub 4} 50%; Fe 75% and SiO{sub 4} 25% and two other samples were assembled in the same geometry, using 100% SiO{sub 4} and 100% Fe. These samples were exposed to a large spectrum of gamma radiation (121 keV to 1408 keV) emitted by sources of {sup 60}Co, {sup 137}Cs and {sup 152}Eu. These gamma radiations were collimated and directed over the doped samples in a high resolution gamma ray spectrometer, whose spectra were analyzed with the Winner Gamma software. The matrix effect intensity is inferred by the percentage differences observed in varying the iron concentration that proved to be more intense for lower energy radiation. (author)

Dosimetric evaluation of scattered and attenuated radiation due to dental restorations in head and neck radiotherapy

Directory of Open Access Journals (Sweden)

Mona Azizi

2018-01-01

Full Text Available In radiotherapy of head and neck cancer, the presence of high density materials modifies photon dose distribution near these high density materials during treatment. The aim of this study is to calculate the backscatter and attenuation effects of a healthy tooth, Amalgam, Ni-Cr alloy and Ceramco on the normal tissues before and after these materials irradiated by 6 and 15 MV photon beams, respectively. All measurements were carried out in a water phantom with dimension of 50 × 50 × 50 cm3with an ionization chamber detector. Two points before and four points after the dental sample were considered to score the photon dose. The depth dose on the central beam axis was explored in a water phantom for source to surface distance (SSD of 100 cm in a 10 × 10 cm2 field size. The percentage dose change was obtained relative to the dose in water versus depth of water, tooth, Amalgam, Ni-Cr alloy and Ceramco for the photon beams. The absolute dose (cGy was measured by prescription of 100 cGy dose in the water phantom at depth of 2.0 and 3.1 cm for 6 and 15 MV photons, respectively. At depth of 0.6 cm, the maximum percentage dose increase was observed with values of 6.99% and 9.43%for Ni-Cr and lowest percentage dose increase of 1.49% and 2.63% are related to the healthy tooth in 6 and 15 MV photon beams, respectively. The maximum absolute dose of 95.58 cGy and 93.64 cGy were observed at depth of 0.6 cm in presence of Ni-Cr alloy for 6 and 15 MV photon beams, respectively. The presence of dental restorations can cause backscattering dose during head and neck radiation therapy. Introduction of compositions and electron density of high density materials can improve the accuracy of dosimetric calculations in treatment planning systems to deliver the relevant dose to target organ and reduce the backscattering dose in healthy tissues in the surrounding of tooth.

Radiomodifying effect of caffeine on mammalian cellular system using gamma radiation and proton beam radiation

International Nuclear Information System (INIS)

Samanth, Sneha P.; Yadav, Usha; Shirsath, K.B.; Desai, Utkarsha N.; Chaurasia, Rajesh K.; Bhat, Nagesh N.; Anjaria, K.B.; Sapra, B.K.

2016-01-01

Caffeine is a commonly consumed neurostimulant in the world. Reports suggest the radiomodifying effects of caffeine against low Linear Energy Transfer (LET) radiation when administered pre and post irradiation by releasing checkpoint arrest. In the present report, the radioprotective and radiosensitizing ability of caffeine (10μM - 2mM) were studied on Chinese Hamster Ovary (CRO) cell line against low as well as high LET radiation when administered pre, post and continuously during radiation. Effect of caffeine treatment on the genotoxicity induced by gamma and proton beam radiation was assessed by micronucleus assay. Effect of caffeine treatment on clonogenic survival of irradiated cells was also assessed

X-ray Beam Spectral Reconstruction Using Laplace Transform and Attenuation Curves

International Nuclear Information System (INIS)

Maeng, Seongjin; Lee, Sang Hoo; Kwon, Dahye; Seo, Jihye; Seo, Kyung Won

2015-01-01

As the use of X-ray tubes is widely spread mainly for medical diagnostic purposes or industrial applications, there is increasing demand for accurate and convenient way getting of X-ray beam spectral information. While measurement methods may provide quite accurate spectral information, these methods still require expensive detectors (example: HPGe, High Purity Germanium detector) and some conversion of measurement information into real spectrum. It is concluded that Laplace transform-based spectral reconstruction technique given in equations (1) and (2) works well for a 50-kV X-ray source. In this paper we obtained the attenuation curve by the use of MCNPX simulations. We were able to rebuild the X-ray spectrum of 50 kV through this research by Monte Carlo simulation (fitting parameters, a: 1.2921, b: 0.2342, ν: 0.6190, R-squared: 0.9930)

Cone-beam CT image contrast and attenuation-map linearity improvement (CALI) for brain stereotactic radiosurgery procedures

Science.gov (United States)

Hashemi, Sayed Masoud; Lee, Young; Eriksson, Markus; Nordström, Hâkan; Mainprize, James; Grouza, Vladimir; Huynh, Christopher; Sahgal, Arjun; Song, William Y.; Ruschin, Mark

2017-03-01

A Contrast and Attenuation-map (CT-number) Linearity Improvement (CALI) framework is proposed for cone-beam CT (CBCT) images used for brain stereotactic radiosurgery (SRS). The proposed framework is used together with our high spatial resolution iterative reconstruction algorithm and is tailored for the Leksell Gamma Knife ICON (Elekta, Stockholm, Sweden). The incorporated CBCT system in ICON facilitates frameless SRS planning and treatment delivery. The ICON employs a half-cone geometry to accommodate the existing treatment couch. This geometry increases the amount of artifacts and together with other physical imperfections causes image inhomogeneity and contrast reduction. Our proposed framework includes a preprocessing step, involving a shading and beam-hardening artifact correction, and a post-processing step to correct the dome/capping artifact caused by the spatial variations in x-ray energy generated by bowtie-filter. Our shading correction algorithm relies solely on the acquired projection images (i.e. no prior information required) and utilizes filtered-back-projection (FBP) reconstructed images to generate a segmented bone and soft-tissue map. Ideal projections are estimated from the segmented images and a smoothed version of the difference between the ideal and measured projections is used in correction. The proposed beam-hardening and dome artifact corrections are segmentation free. The CALI was tested on CatPhan, as well as patient images acquired on the ICON system. The resulting clinical brain images show substantial improvements in soft contrast visibility, revealing structures such as ventricles and lesions which were otherwise un-detectable in FBP-reconstructed images. The linearity of the reconstructed attenuation-map was also improved, resulting in more accurate CT#.

Gelatin/piassava composites treated by Electron Beam Radiation

International Nuclear Information System (INIS)

Takinami, Patricia Yoko Inamura; Shimazaki, Kleber; Moura, Esperidiana Augusta Barretos de; Mastro, Nelida Lucia del; Colombo, Maria Aparecida

2010-01-01

Piassava (Attalea funifera Mart) fiber has been investigated as reinforcement for polymer composites with potential for practical applications. The purpose of the present work was to assess the behavior of specimens of piassava fiber and gelatin irradiated with electron beam at different doses and percentage. The piassava/gelatin specimens were made with 5 and 10% (w/w) piassava fiber, gelatin 25% (w/w), glycerin as plasticizer and acrylamide as copolymer. The samples were irradiated up to 40 kGy using an electron beam accelerator, at room temperature in presence of air. Preliminary results showed mechanical properties enhancement with the increase in radiation dose. (author)

Transverse resonance-radiation pressure on atomic beams and the influence of fluctuations

International Nuclear Information System (INIS)

Bjorkholm, J.E.; Freeman, R.R.; Ashkin, A.; Pearson, D.B.

1979-01-01

We have experimentally demonstrated that a beam of neutral sodium atoms can be focused to a spot diameter of approx. 50 μ using the transverse dipole resonance-radiation pressure exerted by a 40 mW laser beam. Simple analysis shows that in some cases the spot sizes are limited by the random fluctuations of the spontaneous radiation pressure; with 1 W of laser power, spot sizes less than 10 μ should be attainable. The effects of heating by spontaneous scattering can have important detrimental effects in other applications of resonance - radiation pressure on atoms, such as the slowing or guiding of atoms. Consideration of heating effects is of paramount importance in the design of optical traps for neutral atoms. (KBE)

Efficient, radiation-hardened, 800-keV neutral beam injection system

International Nuclear Information System (INIS)

Anderson, O.A.; Cooper, W.S.; Goldberg, D.A.; Ruby, L.; Soroka, L.; Fink, J.H.

1982-10-01

Recent advances and new concepts in negative ion generation, transport, acceleration, and neutrailzation make it appear likely that an efficient, radiation-hardened neutral beam injection system could be developed in time for the proposed FED-A tokamak. These new developments include the operation of steady-state H - ion sources at over 5 A per meter of source length, the concept of using strong-focussing electrostatic structures for low-gradient dc acceleration of high-current sheet beams of negative ions and the transport of these beams around corners, and the development of powerful oxygen-iodine chemical lasers which will make possible the efficient conversion of the negative ions to neutrals using a photodetachment scheme in which the ion beam passes through the laser cavity

Partial protection of baboons against Schistosoma mansoni using radiation-attenuated cryopreserved schistosomula

International Nuclear Information System (INIS)

James, E.R.; Dobinson, A.R.; Otieno, M.; Monorei, J.; Else, J.G.

1986-01-01

Three groups of five baboons were vaccinated in Kenya using three doses of 10,000 viable cryopreserved schistosomula attenuated with either 10, 20 or 60 krad 60 co-irradiation. The results from perfusion indicated reductions in worm burdens in the 10, 20 and 60 krad vaccinated groups of 18%, 23% and 20% respectively, none of which was statistically significant. No stunting of adult worms could be demonstrated in any of the groups. Mean tissue egg burdens were higher in all vaccinated groups and consequently egg production per worm pair was also higher than in the challenge controls. The logistics of preparing and delivering a cryopreserved radiation-attenuated vaccine were amply demonstrated; however, in this study the levels of protection achieved were not statistically significant; possible reasons for this are discussed. (author)

Corrosion by photochemical reaction due to synchrotron radiation in TRISTAN vacuum system

International Nuclear Information System (INIS)

Momose, Takashi; Ishimaru, Hajime

1989-01-01

In the electron-positron collision ring (TMR) in the National Laboratory for High Energy Physics, the operation at the beam energy of 30 GeV is carried out. The critical energy of synchrotron radiation corresponding to this energy is 243 keV which is the highest in the world. Consequently, the radiation damage of various substances due to this radiation has become the problem. From the viewpoint that the TMR is the vacuum system totally made of aluminum alloy for the first time in the world, the problem peculiar to aluminum alloy and the related problem of material damage and the countermeasures are discussed. Beam energy and attenuation length, the radiation dose in the TMR tunnel, the beam current-time product of TMR, the examples of radiation damage such as the atmosphere in TAR, the atmosphere in TMR, the aluminum bellows, aluminum chamber and lead radiation shield in TMR, the aluminum beam line in the atmosphere of TAR, the heat-insulating kapton film with vacuum deposited aluminum films, Teflon and polystyrene insulators, the stainless steel terminals and cables for position monitors, the O-rings for gate valves, polyvinyl chloride and so on are reported. (K.I.)

Accuracy and Radiation Dose of CT-Based Attenuation Correction for Small Animal PET: A Monte Carlo Simulation Study

International Nuclear Information System (INIS)

Yang, Ching-Ching; Chan, Kai-Chieh

2013-06-01

-Small animal PET allows qualitative assessment and quantitative measurement of biochemical processes in vivo, but the accuracy and reproducibility of imaging results can be affected by several parameters. The first aim of this study was to investigate the performance of different CT-based attenuation correction strategies and assess the resulting impact on PET images. The absorbed dose in different tissues caused by scanning procedures was also discussed to minimize biologic damage generated by radiation exposure due to PET/CT scanning. A small animal PET/CT system was modeled based on Monte Carlo simulation to generate imaging results and dose distribution. Three energy mapping methods, including the bilinear scaling method, the dual-energy method and the hybrid method which combines the kVp conversion and the dual-energy method, were investigated comparatively through assessing the accuracy of estimating linear attenuation coefficient at 511 keV and the bias introduced into PET quantification results due to CT-based attenuation correction. Our results showed that the hybrid method outperformed the bilinear scaling method, while the dual-energy method achieved the highest accuracy among the three energy mapping methods. Overall, the accuracy of PET quantification results have similar trend as that for the estimation of linear attenuation coefficients, whereas the differences between the three methods are more obvious in the estimation of linear attenuation coefficients than in the PET quantification results. With regards to radiation exposure from CT, the absorbed dose ranged between 7.29-45.58 mGy for 50-kVp scan and between 6.61-39.28 mGy for 80-kVp scan. For 18 F radioactivity concentration of 1.86x10 5 Bq/ml, the PET absorbed dose was around 24 cGy for tumor with a target-to-background ratio of 8. The radiation levels for CT scans are not lethal to the animal, but concurrent use of PET in longitudinal study can increase the risk of biological effects. The

Low skeletal muscle radiation attenuation and visceral adiposity are associated with overall survival and surgical site infections in patients with pancreatic cancer.

Science.gov (United States)

van Dijk, David P J; Bakens, Maikel J A M; Coolsen, Mariëlle M E; Rensen, Sander S; van Dam, Ronald M; Bours, Martijn J L; Weijenberg, Matty P; Dejong, Cornelis H C; Olde Damink, Steven W M

2017-04-01

Cancer cachexia and skeletal muscle wasting are related to poor survival. In this study, quantitative body composition measurements using computed tomography (CT) were investigated in relation to survival, post-operative complications, and surgical site infections in surgical patients with cancer of the head of the pancreas. A prospective cohort of 199 patients with cancer of the head of the pancreas was analysed by CT imaging at the L3 level to determine (i) muscle radiation attenuation (average Hounsfield units of total L3 skeletal muscle); (ii) visceral adipose tissue area; (iii) subcutaneous adipose tissue area; (iv) intermuscular adipose tissue area; and (v) skeletal muscle area. Sex-specific cut-offs were determined at the lower tertile for muscle radiation attenuation and skeletal muscle area and the higher tertile for adipose tissues. These variables of body composition were related to overall survival, severe post-operative complications (Dindo-Clavien ≥ 3), and surgical site infections (wounds inspected daily by an independent trial nurse) using Cox-regression analysis and multivariable logistic regression analysis, respectively. Low muscle radiation attenuation was associated with shorter survival in comparison with moderate and high muscle radiation attenuation [median survival 10.8 (95% CI: 8.8-12.8) vs. 17.4 (95% CI: 14.7-20.1), and 18.5 (95% CI: 9.2-27.8) months, respectively; P site infection rate, OR: 2.4 (95% CI: 1.1-5.3; P = 0.027). Low muscle radiation attenuation was associated with reduced survival, and high visceral adiposity was associated with an increase in surgical site infections. The strong correlation between muscle radiation attenuation and intermuscular adipose tissue suggests the presence of ectopic fat in muscle, warranting further investigation. CT image analysis could be implemented in pre-operative risk assessment to assist in treatment decision-making. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle

EXAFS-spectroscopy on synchrotron radiation beam

CERN Document Server

Aksenov, V L; Kuzmin, A Y; Purans, Y

2001-01-01

In the review the basis theoretical principles of EXAFS spectroscopy are given, as one of principal directions of an absorption spectroscopy permitting with a high accuracy to gain parameters of the short-range order in multicomponent amorphous and quasi-crystal mediums. The methods of the analysis of EXAFS spectra with allowance of effects of multiply scattering are featured. The exposition of the experimental set-ups, which realize the method of EXAFS spectroscopy on beams of SR, requirement of the monochromatization of radiation beams are given. For investigation of phase transition and external effects the energy-dispersive EXAFS spectrometer is creating at the National center of SR Kurchatov Institute which can measure the EXAFS spectrum with a time resolution 3-5 ms. The experimental results on investigation (by the EXAFS spectroscopy method) of oxides of tungsten and molybdenum are given, which have unique property: the variable valence of an ion of metal is depending on external action. The most inter...

Gamma-ray beam attenuation to assess the influence of soil texture on structure deformation

International Nuclear Information System (INIS)

Pires, L.F.; Bacchi, O.O.S.; Dias, N.M.P.

2006-01-01

Gamma-ray beam attenuation is a non-invasive technique that permits analysis of soil porosity without disturbing the region of interest of the core sample. The technique has as additional advantage to allow measurements point by point on a millimetric scale in contrast to other methodologies that are invasive and analyze the soil properties in the bulk sample volume. Soil porosity can be used as an important parameter to quantify soil structural damages, which affect soil aeration, water movement and retention. In this study, porosities of three soils different in texture were measured at various positions in order to analyze the impact of the sampling procedure on the structure of each particular soil texture. The gamma-ray attenuation system consisted of an 241 Am radioactive source having an activity of 3.7 GBq, collimated with cylindrical lead collimators of 2 mm diameter. The results obtained show the presence of dense regions near the edges of samples and that different soil textures can suffer distinct deformations at sampling. (author)

Effective radiation attenuation calibration for breast density: compression thickness influences and correction

Directory of Open Access Journals (Sweden)

Thomas Jerry A

2010-11-01

Full Text Available Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure.

Noncoplanar Beam Angle Class Solutions to Replace Time-Consuming Patient-Specific Beam Angle Optimization in Robotic Prostate Stereotactic Body Radiation Therapy

International Nuclear Information System (INIS)

Rossi, Linda; Breedveld, Sebastiaan; Aluwini, Shafak; Heijmen, Ben

2015-01-01

Purpose: To investigate development of a recipe for the creation of a beam angle class solution (CS) for noncoplanar prostate stereotactic body radiation therapy to replace time-consuming individualized beam angle selection (iBAS) without significant loss in plan quality, using the in-house “Erasmus-iCycle” optimizer for fully automated beam profile optimization and iBAS. Methods and Materials: For 30 patients, Erasmus-iCycle was first used to generate 15-, 20-, and 25-beam iBAS plans for a CyberKnife equipped with a multileaf collimator. With these plans, 6 recipes for creation of beam angle CSs were investigated. Plans of 10 patients were used to create CSs based on the recipes, and the other 20 to independently test them. For these tests, Erasmus-iCycle was also used to generate intensity modulated radiation therapy plans for the fixed CS beam setups. Results: Of the tested recipes for CS creation, only 1 resulted in 15-, 20-, and 25-beam noncoplanar CSs without plan deterioration compared with iBAS. For the patient group, mean differences in rectum D 1cc , V 60GyEq , V 40GyEq , and D mean between 25-beam CS plans and 25-beam plans generated with iBAS were 0.2 ± 0.4 Gy, 0.1% ± 0.2%, 0.2% ± 0.3%, and 0.1 ± 0.2 Gy, respectively. Differences between 15- and 20-beam CS and iBAS plans were also negligible. Plan quality for CS plans relative to iBAS plans was also preserved when narrower planning target volume margins were arranged and when planning target volume dose inhomogeneity was decreased. Using a CS instead of iBAS reduced the computation time by a factor of 14 to 25, mainly depending on beam number, without loss in plan quality. Conclusions: A recipe for creation of robust beam angle CSs for robotic prostate stereotactic body radiation therapy has been developed. Compared with iBAS, computation times decreased by a factor 14 to 25. The use of a CS may avoid long planning times without losses in plan quality

Noncoplanar Beam Angle Class Solutions to Replace Time-Consuming Patient-Specific Beam Angle Optimization in Robotic Prostate Stereotactic Body Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Rossi, Linda, E-mail: l.rossi@erasmusmc.nl; Breedveld, Sebastiaan; Aluwini, Shafak; Heijmen, Ben

2015-07-15

Purpose: To investigate development of a recipe for the creation of a beam angle class solution (CS) for noncoplanar prostate stereotactic body radiation therapy to replace time-consuming individualized beam angle selection (iBAS) without significant loss in plan quality, using the in-house “Erasmus-iCycle” optimizer for fully automated beam profile optimization and iBAS. Methods and Materials: For 30 patients, Erasmus-iCycle was first used to generate 15-, 20-, and 25-beam iBAS plans for a CyberKnife equipped with a multileaf collimator. With these plans, 6 recipes for creation of beam angle CSs were investigated. Plans of 10 patients were used to create CSs based on the recipes, and the other 20 to independently test them. For these tests, Erasmus-iCycle was also used to generate intensity modulated radiation therapy plans for the fixed CS beam setups. Results: Of the tested recipes for CS creation, only 1 resulted in 15-, 20-, and 25-beam noncoplanar CSs without plan deterioration compared with iBAS. For the patient group, mean differences in rectum D{sub 1cc}, V{sub 60GyEq}, V{sub 40GyEq}, and D{sub mean} between 25-beam CS plans and 25-beam plans generated with iBAS were 0.2 ± 0.4 Gy, 0.1% ± 0.2%, 0.2% ± 0.3%, and 0.1 ± 0.2 Gy, respectively. Differences between 15- and 20-beam CS and iBAS plans were also negligible. Plan quality for CS plans relative to iBAS plans was also preserved when narrower planning target volume margins were arranged and when planning target volume dose inhomogeneity was decreased. Using a CS instead of iBAS reduced the computation time by a factor of 14 to 25, mainly depending on beam number, without loss in plan quality. Conclusions: A recipe for creation of robust beam angle CSs for robotic prostate stereotactic body radiation therapy has been developed. Compared with iBAS, computation times decreased by a factor 14 to 25. The use of a CS may avoid long planning times without losses in plan quality.

Study of performance of electronic dosemeters in continuous and pulsed X-radiation beams

International Nuclear Information System (INIS)

Guimaraes, Margarete Cristina

2014-01-01

Personal radiation monitoring is a basic procedure to verify the compliance to regulatory requirements for radiological protection. Electronic personal dosimeters (EPD) based on solid state detectors have largely been used for personnel monitoring; including for pulsed radiation beams where their responses are not well known and deficiencies have been reported. In this work, irradiation conditions for testing the response of EPDs in both continuous and pulsed X-ray beams were studied to be established in a constant potential Seifert-Pantak and in a medical Pulsar 800 Plus VMI X-ray machines. Characterization of X-ray beams was done in terms of tube voltage, half-value layer, mean energy and air kerma rate. A Xi R/F Unfors solid state dosimeter used as reference for air kerma measurements was verified against a RC-6 and 10X6-6 Radical ionization chambers as far its metrological coherence. Rad-60 RADOS, PDM- 11 Aloka and EPD MK2 Thermo electron EPDs were selected to be tested in terms of relative intrinsic error and energy response in similar to IEC RQR, IEC RQA and ISO N reference radiations. Results demonstrated the reliability of the solid state Xi R/F Unfors dosimeter to be as reference dosimeter although its response was affected by heavily filtered beams. Results also showed that relative intrinsic errors in the response of the EPDs in terms of personal dose equivalent, Hp(10), were higher than the requirement established for continuous beams. In pulsed beams, some EPDs showed inadequate response and high relative intrinsic errors. This work stressed the need of performing additional checks for EPDs, besides the limited 137 Cs beam calibration, before using them in pulsed X-ray beams. (author)

Beam shaping of laser diode radiation by waveguides with arbitrary cladding geometry written with fs-laser radiation.

Science.gov (United States)

Beckmann, Dennis; Schnitzler, Daniel; Schaefer, Dagmar; Gottmann, Jens; Kelbassa, Ingomar

2011-12-05

Waveguides with arbitrary cross sections are written in the volume of Al(2)O(3)-crystals using tightly focused femtosecond laser radiation. Utilizing a scanning system with large numerical aperture, complex cladding geometries are realized with a precision around 0.5 µm and a scanning speed up to 100 mm/s. Individual beam and mode shaping of laser diode radiation is demonstrated by varying the design of the waveguide cladding. The influence of the writing parameters on the waveguide properties are investigated resulting in a numerical aperture of the waveguides in the range of 0.1. This direct laser writing technique enables optical devices which could possibly replace bulky beam shaping setups with an integrated solution.

The effect of a metal hip prosthesis on the radiation dose in therapeutic photon beam irradiations

International Nuclear Information System (INIS)

Lin, S.-Y.; Chu, T.-C.; Lin, J.-P.; Liu, M.-T.

2002-01-01

Prostate and cervical cancer patients are often treated with external X-ray beams of bi-lateral incidence. Such treatment may incur some dose effect that cannot be predicted precisely in commercial treatment planning systems (TPS) for patients having undergone total hip replacement. This study performs a Monte Carlo (MC) simulation and an analytical calculation (convolution superposition algorithm which is implemented in ADAC TPS) of a 6 MV, 5x5 cm 2 X-ray beam incident into water with the existence of hip prosthesis, e.g. Ti6Al4V and CoCrMo alloy. The results indicate that ADAC TPS cannot precisely account for the scatter and backscatter radiation that a metal hip prosthesis causes. For percent depth dose (PDD) curves, the maximum underdosage of ADAC TPS up to 5 mm above the interface between dense material and water is 5%, 20% and 27% for PDD Bone , PDD Ti and PDD Co , respectively. The dose re-buildup, which occurs behind the hip region, becomes more and more obvious for denser medium existed in water. Increasing inhomogeneity also enhances the underdosage of ADAC for greater depth (>10 cm), as the figures of nearly 2% in PDD Bone , PDD Ti and 4-5% in PDD Co reveal. Overestimating the attenuated power of high-density non-water material in ADAC TPS causes this underdosage. For dose profiles, no significant differences were found in Profile Bone at any depth. Profile Ti reveals that MC slightly exceeds ADAC at off-axis position 1.0-2.0 cm. Profile Co reveals this more obviously. This finding means that scatter radiation from these denser materials is significant and cannot be predicted precisely in ADAC

Design of a synchrotron radiation detector for the test beam lines at the Superconducting Super Collider Laboratory

International Nuclear Information System (INIS)

Hutton, R.D.

1994-01-01

As part of the particle- and momentum-tagging instrumentation required for the test beam lines of the Superconducting Super Collider (SSC), the synchrotron radiation detector (SRD) was designed to provide electron tagging at momentum above 75 GeV. In a parallel effort to the three test beam lines at the SSC, schedule demands required testing and calibration operations to be initiated at Fermilab. Synchrotron radiation detectors also were to be installed in the NM and MW beam lines at Femilab before the test beam lines at the SSC would become operational. The SRD is the last instrument in a series of three used in the SSC test beam fines. It follows a 20-m drift section of beam tube downstream of the last silicon strip detector. A bending dipole just in of the last silicon strip detector produces the synchrotron radiation that is detected in a 50-mm-square cross section NaI crystal. A secondary scintillator made of Bicron BC-400 plastic is used to discriminate whether it is synchrotron radiation or a stray particle that causes the triggering of the NaI crystal's photo multiplier tube (PMT)

Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

International Nuclear Information System (INIS)

Itskovsky, M. A.; Maniv, T.; Cohen, H.

2008-01-01

A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating (SiO 2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the 'classical' spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive 'tip detectors' of electronically excited nanostructures

Silicon radiation detector analysis using back electron beam induced current

International Nuclear Information System (INIS)

Guye, R.

1987-01-01

A new technique for the observation and analysis of defects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p + n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is a sensitive probe of localized trapping centers, either at the junction surface or somewhere in the volume of the silicon crystal. (orig.)

Landing gear noise attenuation

Science.gov (United States)

Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

2011-01-01

A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

Radiation processing of natural polymers using low energy electron beam

International Nuclear Information System (INIS)

Kume, Tamikazu

2004-01-01

Radiation processing is widely used in Japan and the economic scale of radiation application amounted to about 71 b$ (ratio relative to GDP: 1.7%) in total. It consisted of 60 b$ (85%) in industry, 10 b$ (14%) in medicine and 1 b$ (1%) in agriculture. Irradiation using gamma-ray from 60 Co and electron beam is commercially used for the sterilization and modification of materials. Utilization of natural polymers by radiation has been investigated for recycling the natural resources and reducing the environmental pollution. Polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin were easily degraded by irradiation and induced various kinds of biological activities, i.e. anti-bacterial activity, elicitor activity, plant growth promotion, suppression of environmental stress on plants. Radiation degraded chitosan was effective to enhance the growth of plants in tissue culture. Low energy electron beam (EB) irradiation has a variety of applications and good safety. A self-shielded low energy electron accelerator system needs an initial investment much lower than a 60 Co facility. It was demonstrated that the liquid sample irradiation system using low energy EB was effective not only for the preparation of degraded polysaccharides but also for radiation vulcanization of natural rubber latex (RVNRL). Some carbohydrate derivatives, carboxymethylcellulose (CMC), carboxymethyl-starch and carboxymethyl-chitin/chitosan, can be crosslinked under certain radiation condition and produced the biodegradable hydrogel for medical and agricultural use. Treatment of soybean seeds by low energy EB enhanced the growth and the number of rhizobia on the root. (author)

Role of beam orientation optimization in intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Pugachev, Andrei; Li, Jonathan G.; Boyer, Arthur L.; Hancock, Steven L.; Le, Quynh-Thu; Donaldson, Sarah S.; Lei Xing

2001-01-01

Purpose: To investigate the role of beam orientation optimization in intensity-modulated radiation therapy (IMRT) and to examine the potential benefits of noncoplanar intensity-modulated beams. Methods and Materials: A beam orientation optimization algorithm was implemented. For this purpose, system variables were divided into two groups: beam position (gantry and table angles) and beam profile (beamlet weights). Simulated annealing was used for beam orientation optimization and the simultaneous iterative inverse treatment planning algorithm (SIITP) for beam intensity profile optimization. Three clinical cases were studied: a localized prostate cancer, a nasopharyngeal cancer, and a paraspinal tumor. Nine fields were used for all treatments. For each case, 3 types of treatment plan optimization were performed: (1) beam intensity profiles were optimized for 9 equiangular spaced coplanar beams; (2) orientations and intensity profiles were optimized for 9 coplanar beams; (3) orientations and intensity profiles were optimized for 9 noncoplanar beams. Results: For the localized prostate case, all 3 types of optimization described above resulted in dose distributions of a similar quality. For the nasopharynx case, optimized noncoplanar beams provided a significant gain in the gross tumor volume coverage. For the paraspinal case, orientation optimization using noncoplanar beams resulted in better kidney sparing and improved gross tumor volume coverage. Conclusion: The sensitivity of an IMRT treatment plan with respect to the selection of beam orientations varies from site to site. For some cases, the choice of beam orientations is important even when the number of beams is as large as 9. Noncoplanar beams provide an additional degree of freedom for IMRT treatment optimization and may allow for notable improvement in the quality of some complicated plans

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.

Working group report on the required atomic database for neutral hydrogen beam penetration in large tokamaks

International Nuclear Information System (INIS)

Cox, M.; Boley, C.D.; Janev, R.K.

1989-01-01

This report discusses the required atomic database for the physical processes involved in the beam attenuation kinetics, when multistep processes are included, i.e., electron and proton impact processes, impurity-ion impact processes, radiative processes, as well as Lorentz field ionization. It also discusses the required accuracies of different parts of the data base in order to achieve the overall accuracy of about 10 percent that is required for the total beam stopping power cross section. 3 refs

Implantation of radiodiagnostic reference radiations at the CDTN/CNEN for dosemeter calibration

International Nuclear Information System (INIS)

Baptista Neto, A.T.; Oliveira, P.M.C. de; Ferreira, F.C.B.

2009-01-01

A reliable dosimetry in diagnostic radiology is based on the traceability of calibrated and type-tested dosimeters in reference radiations that were established by the International Electrotechnical Commission (IEC). Metrology laboratories are expected to implement the reference radiations by reproducing the x-ray beam parameters within standard limits. This work shows the results of the implementation in the CDTN/CNEN-MG of the reference radiations for diagnostic radiology. The half value-layers and the homogeneity coefficients were determined for the primary (RQR), attenuated (RQA) and computerized tomography (RQT) x-ray beams. Results complied with the IEC limits which it means that the CDTN and the IEC reference radiations are similar and they can be used for calibration and type-testing of dosimeters to be used in diagnostic radiology. (author)

Beam structure of Jupiter's decametric radiation

Energy Technology Data Exchange (ETDEWEB)

Maeda, K; Carr, T D

1984-03-08

The well-defined zones of central meridian longitude within which the probability of jovian radio emission at frequencies near 22 MHz is relatively high are known as sources A, B and C. Each consists of a component for which the emission probability is strongly correlated with Io's orbital position, and another that is Io-unrelated. The paper presents convincing evidence based on concurrent observations from two Voyager spacecraft and a terrestrial observatory that the component of source A radiation that is not correlated with Io's position is generally emitted in co-rotating searchlight beams of distinctive cross-sectional shape.

Generation and characterization of ultra-short electron beams for single spike infrared FEL radiation at SPARC_LAB

Science.gov (United States)

Villa, F.; Anania, M. P.; Artioli, M.; Bacci, A.; Bellaveglia, M.; Bisesto, F. G.; Biagioni, A.; Carpanese, M.; Cardelli, F.; Castorina, G.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Croia, M.; Curcio, A.; Dattoli, G.; Gallo, A.; Di Giovenale, D.; Di Palma, E.; Di Pirro, G.; Ferrario, M.; Filippi, F.; Giannessi, L.; Giribono, A.; Marocchino, A.; Massimo, F.; Mostacci, A.; Petralia, A.; Petrarca, M.; Petrillo, V.; Piersanti, L.; Pioli, S.; Pompili, R.; Romeo, S.; Rossi, A. R.; Scifo, J.; Shpakov, V.; Vaccarezza, C.

2017-09-01

The technique for producing and measuring few tens of femtosecond electron beams, and the consequent generation of few tens femtoseconds single spike FEL radiation pulses at SPARC_LAB is presented. The undulator has been used in the double role of radiation source and diagnostic tool for the characterization of the electron beam. The connection between the electron bunch length and the radiation bandwidth is analyzed.

Radiative interaction of a focused relativistic electron beam in energy-loss spectroscopy of nanoscopic platelets

Science.gov (United States)

Itskovsky, M. A.; Cohen, H.; Maniv, T.

2008-07-01

A quantum-mechanical scattering theory for relativistic, highly focused electron beams in the vacuum near nanoscopic platelets is presented, revealing an excitation mechanism due to the electron wave scattering from the platelet edges. Radiative electromagnetic excitations within the light cone are shown to arise, allowed by the breakdown of momentum conservation along the beam axis in the inelastic-scattering process. Calculated for metallic (silver and gold) and insulating ( SiO2 and MgO) nanoplatelets, radiative features are revealed above the main surface-plasmon-polariton peak, and dramatic enhancements in the electron-energy-loss probability at gaps of the “classical” spectra are found. The corresponding radiation should be detectable in the vacuum far-field zone, with e beams exploited as sensitive “tip detectors” of electronically excited nanostructures.

Radiation hygienization of cattle and swine slurry with high energy electron beam

International Nuclear Information System (INIS)

Skowron, Krzysztof; Olszewska, Halina; Paluszak, Zbigniew; Zimek, Zbigniew; Kałuska, Iwona; Skowron, Karolina Jadwiga

2013-01-01

The research was carried out to assess the efficiency of radiation hygienization of cattle and swine slurry of different density using the high energy electron beam based on the inactivation rate of Salmonella ssp, Escherichia coli, Enterococcus spp and Ascaris suum eggs. The experiment was conducted with use of the linear electron accelerator Elektronika 10/10 in Institute of Nuclear Chemistry and Technology in Warsaw. The inoculated slurry samples underwent hygienization with high energy electron beam of 1, 3, 5, 7 and 10 kGy. Numbers of reisolated bacteria were determined according to the MPN method, using typical microbiological media. Theoretical lethal doses, D 90 doses and hygienization efficiency of high energy electron beam were determined. The theoretical lethal doses for all tested bacteria ranged from 3.63 to 8.84 kGy and for A. suum eggs from 4.07 to 5.83 kGy. Salmonella rods turned out to be the most sensitive and Enterococcus spp were the most resistant to electron beam hygienization. The effectiveness or radiation hygienization was lower in cattle than in swine slurry and in thick than in thin one. Also the species or even the serotype of bacteria determined the dose needed to inactivation of microorganisms. - Highlights: ► The hygienic efficiency of electron beam against slurry was researched. ► The hygienization efficiency depended on the slurry characteristics and microorganism species. ► In most of the cases 7 kGy dose was sufficient for slurry hygienization. ► Dose below 1 kGy allowed for 90% elimination of microorganism population. ► The radiation hygienization is a good alternative for typical slurry treatment methods

Computer-assisted selection of coplanar beam orientations in intensity-modulated radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Pugachev, A.; Xing, L. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States)]. E-mail: lei@reyes.stanford.edu

2001-09-01

In intensity-modulated radiation therapy (IMRT), the incident beam orientations are often determined by a trial and error search. The conventional beam's-eye view (BEV) tool becomes less helpful in IMRT because it is frequently required that beams go through organs at risk (OARs) in order to achieve a compromise between the dosimetric objectives of the planning target volume (PTV) and the OARs. In this paper, we report a beam's-eye view dosimetrics (BEVD) technique to assist in the selection of beam orientations in IMRT. In our method, each beam portal is divided into a grid of beamlets. A score function is introduced to measure the 'goodness' of each beamlet at a given gantry angle. The score is determined by the maximum PTV dose deliverable by the beamlet without exceeding the tolerance doses of the OARs and normal tissue located in the path of the beamlet. The overall score of the gantry angle is given by a sum of the scores of all beamlets. For a given patient, the score function is evaluated for each possible beam orientation. The directions with the highest scores are then selected as the candidates for beam placement. This procedure is similar to the BEV approach used in conventional radiation therapy, except that the evaluation by a human is replaced by a score function to take into account the intensity modulation. This technique allows one to select beam orientations without the excessive computing overhead of computer optimization of beam orientation. It also provides useful insight into the problem of selection of beam orientation and is especially valuable for complicated cases where the PTV is surrounded by several sensitive structures and where it is difficult to select a set of 'good' beam orientations. Several two-dimensional (2D) model cases were used to test the proposed technique. The plans obtained using the BEVD-selected beam orientations were compared with the plans obtained using equiangular spaced beams. For

Study of radioactivity and radiation attenuation of a new heavy weight concrete

International Nuclear Information System (INIS)

Ramadan, A.B.; Fouda, S.; EL-Mongy, S.; Hodhod, O.; Yousef, M.

2005-01-01

The present study is concerned with studying the radioactivity levels and efficiency of proposed heavy weight concrete as a shielding material for low and intermediate level radioactive wastes. Effect of elevated temperatures on radiation attenuation characteristics of proposed materials was also studied. Three types of local natural aggregates (iron ores) namely magnetite, limonite and hematite have been prepared, analyzed for their radioactivity and tested to determine their suitability for the manufacture of heavy weight concrete, which can be used for shielding. Hematite was excluded and two types of concrete have been prepared by using magnetite and limonite. The gamma spectrometry and neutron activation have been used to determine both uranium and thorium contents in the investigated materials. The results obtained by the two methods showed that uranium and thorium were within the acceptable low levels. It was observed that the two types of concrete have good attenuation properties

Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy

International Nuclear Information System (INIS)

Sarmento, Sandra; Costa, Filipa; Pereira, Alexandre; Lencart, Joana; Dias, Anabela; Cunha, Luís; Sousa, Olga; Silva, José Pedro; Santos, Lúcio

2015-01-01

Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect target irradiation. The TachoSil (TS) surgical patch, when activated, creates a fibrin clot at the surgical site to achieve haemostasis. The aim of this work was to determine the effect of TS on the dose distribution, and ascertain whether it could be used in combination with IOERT. This characterization was extended to include high dose rate (HDR) intraoperative brachytherapy, which is sometimes used at other institutions instead of IOERT. CT images of the TS patch were acquired for initial characterization. Dosimetric measurements were performed in a water tank phantom, using a conventional LINAC with a hard-docking system of cylindrical applicators. Percentage Depth Dose (PDD) curves were obtained, and measurements made at the depth of dose maximum for the three clinically used electron energies (6, 9 and 12MeV), first without any attenuator and then with the activated patch of TS completely covering the tip of the IOERT applicator. For HDR brachytherapy, a measurement setup was improvised using a solid water phantom and a Farmer ionization chamber. Our measurements show that the attenuation of a TachoSil patch is negligible, both for high energy electron beams (6 to 12MeV), and for a HDR 192 Ir brachytherapy source. Our results cannot be extrapolated to lower beam energies such as 50 kVp X-rays, which are sometimes used for breast IORT. The TachoSil surgical patch can be used in IORT procedures using 6MeV electron energies or higher, or HDR 192 Ir brachytherapy

Attenuation measurements show that the presence of a TachoSil surgical patch will not compromise target irradiation in intra-operative electron radiation therapy or high-dose-rate brachytherapy.

Science.gov (United States)

Sarmento, Sandra; Costa, Filipa; Pereira, Alexandre; Lencart, Joana; Dias, Anabela; Cunha, Luís; Sousa, Olga; Silva, José Pedro; Santos, Lúcio

2015-01-09

Surgery of locally advanced and/or recurrent rectal cancer can be complemented with intra-operative electron radiation therapy (IOERT) to deliver a single dose of radiation directly to the unresectable margins, while sparing nearby sensitive organs/structures. Haemorrhages may occur and can affect the dose distribution, leading to an incorrect target irradiation. The TachoSil (TS) surgical patch, when activated, creates a fibrin clot at the surgical site to achieve haemostasis. The aim of this work was to determine the effect of TS on the dose distribution, and ascertain whether it could be used in combination with IOERT. This characterization was extended to include high dose rate (HDR) intraoperative brachytherapy, which is sometimes used at other institutions instead of IOERT. CT images of the TS patch were acquired for initial characterization. Dosimetric measurements were performed in a water tank phantom, using a conventional LINAC with a hard-docking system of cylindrical applicators. Percentage Depth Dose (PDD) curves were obtained, and measurements made at the depth of dose maximum for the three clinically used electron energies (6, 9 and 12MeV), first without any attenuator and then with the activated patch of TS completely covering the tip of the IOERT applicator. For HDR brachytherapy, a measurement setup was improvised using a solid water phantom and a Farmer ionization chamber. Our measurements show that the attenuation of a TachoSil patch is negligible, both for high energy electron beams (6 to 12MeV), and for a HDR (192)Ir brachytherapy source. Our results cannot be extrapolated to lower beam energies such as 50 kVp X-rays, which are sometimes used for breast IORT. The TachoSil surgical patch can be used in IORT procedures using 6MeV electron energies or higher, or HDR (192)Ir brachytherapy.

A facility for liquid-phase radiation experiments on heavy ion beams

Energy Technology Data Exchange (ETDEWEB)

Stuglik, Z; Zvara, I; Yakushev, A B; Timokhin, S N [Flerov Lab. of Nuclear Reactions, Dubna (Russian Federation). Joint Inst. for Nuclear Research

1994-05-01

The facility for liquid-phase radiation experiments installed on the beam line of the U-400 cyclotron in the Flerov Laboratory of Nuclear Reactions, JINR, Dubna, is described. The accelerator provides intermediate energy (some 10 MeV/nucleon) beams of ions ranging from Li to Xe. Preliminary results on the radiolysis of the Fricke solution and malachite green in ethanol by {sup 11}B, {sup 24}Mg and {sup 40}Ca ions are presented. (author).

Terahertz radiation generation by beating of two laser beams in a collisional plasma with oblique magnetic field

Science.gov (United States)

Hematizadeh, Ayoob; Jazayeri, Seyed Masud; Ghafary, Bijan

2018-02-01

A scheme for excitation of terahertz (THz) radiation is presented by photo mixing of two super-Gaussian laser beams in a rippled density collisional magnetized plasma. Lasers having different frequencies and wave numbers but the same electric fields create a ponderomotive force on the electrons of plasma in the beating frequency. Super-Gaussian laser beam has the exclusive features such as steep gradient in laser intensity distribution, wider cross-section in comparison with Gaussian profiles, which make stronger ponderomotive force and higher THz radiation. The magnetic field is considered oblique to laser beams propagation direction; in this case, depending on the phase matching conditions different mode waves can propagate in plasma. It is found that amplitude and efficiency of the emitted THz radiation not only are sensitive to the beating frequency, collision frequency, and magnetic field strength but to the angle between laser beams and static magnetic field. The efficiency of THz radiation can be optimized in a certain angle.

Radiation effects on optical data transmission systems

International Nuclear Information System (INIS)

Leskovar, B.

1989-01-01

The state of the art of optical transmitters, low loss fiber waveguides and receivers in both steady state and pulsed radiation environments is reviewed and summarized. Emphasis is placed on the effects of irradiation on the performance of light emitting and laser diodes, optical fiber waveguides and photodiodes. The influence of radiation-induced attenuation of optical fibers due to total dose, dose rate, time after irradiation, temperature, radiation history, photobleaching, OH and impurity content, dopant type and concentration is described. The performance of candidate components of the transmission system intended for deployment in the Superconducting Super Collider Detector and primary beam tunnel nuclear environment is discussed

Smith-Purcell radiation from a 50 MeV beam

Energy Technology Data Exchange (ETDEWEB)

Brownell, J.H.; Walsh, J. [Dartmouth Coll., Hanover, NH (United States). Dept. of Physics and Astronomy; Kirk, H.G.; Fernow, R.C. [Brookhaven National Lab., Upton, NY (United States). Dept. of Physics; Robertson, S.H. [Univ. of Colorado, Boulder, CO (United States). Dept. of Astrophysics and Geophysics

1996-10-01

A 50 MeV electron beam and a 1 mm period, 5{degree} blaze, echelle grating have been used to produce radiation in the mid-infrared spectral region. The emission is highly collimated and forward-directed. The intensity level in the few ps pulse (2 nJ/sr) indicates a degree of coherent enhancement.

Smith-Purcell radiation from a 50 MeV beam

International Nuclear Information System (INIS)

Brownell, J.H.; Walsh, J.; Kirk, H.G.; Fernow, R.C.; Robertson, S.H.

1996-10-01

A 50 MeV electron beam and a 1 mm period, 5 degree blaze, echelle grating have been used to produce radiation in the mid-infrared spectral region. The emission is highly collimated and forward-directed. The intensity level in the few ps pulse (2 nJ/sr) indicates a degree of coherent enhancement

SU-F-P-28: A Method of Maximize the Noncoplanar Beam Orientations and Assure the Beam Delivery Clearance for Stereotactic Body Radiation Therapy (SBRT)

Energy Technology Data Exchange (ETDEWEB)

Zhu, J [Presence St. Joseph Medical Ctr., Joliet, IL (United States)

2016-06-15

Purpose: Develop a method to maximize the noncoplanar beam orientations and assure the beam delivery clearance for SBRT, therefore, optimize the dose conformality to the target, increase the dose sparing to the critical normal organs and reduce the hot spots in the body. Methods: A SBRT body frame (Elekta, Stockholm, Sweden) was used for patient immobilization and target localization. The SBRT body frame has CT fiducials on its side frames. After patient’s CT scan, the radiation treatment isocenter was defined and its coordinators referring to the body frame was calculated in the radiation treatment planning process. Meanwhile, initial beam orientations were designed based on the patient target and critical organ anatomy. The body frame was put on the linear accelerator couch and positioned to the calculated isocenter. Initially designed beam orientations were manually measured by tuning the body frame position on the couch, the gantry and couch angles. The finalized beam orientations were put into the treatment planning for dosimetric calculations. Results: Without patient presence, an optimal set of beam orientations were designed and validated. The radiation treatment plan was optimized and guaranteed for delivery clearance. Conclusion: The developed method is beneficial and effective in SBRT treatment planning for individual patient. It first allows maximizing the achievable noncoplanar beam orientation space, therefore, optimize the treatment plan for specific patient. It eliminates the risk that a plan needs to be modified due to the gantry and couch collision during patient setup.

Dosimetry study for electron beam irradiation in radiation processing

International Nuclear Information System (INIS)

Sunaga, Hiromi; Haruyama, Yasuyuki; Takizawa, Haruki; Kojima, Takuji; Yotsumoto, Keiichi

1995-01-01

For certain critical applications such as medical device sterilization and food irradiation, accurate calibration of electron energy and absorbed dose is required to assure the quality of irradiated products. To meet this requirement, TRCRE, JAERI has carried out research and development on high dose radiation dosimetry for electron beams in the energy range used in radiation processing (0.15 - 3.0 MeV). JAERI has developed a simultaneous electron beam energy and dosimeter calibration system that consist of a total absorption calorimeter, an electron current density meter, and a stacked thin-film dosimeter set. For low energy electrons, where it is important to measure the depth-dose profile in materials with high depth resolution, we studied the feasibility of a method using Gafchromic film dosimeters. This film, which has an 8-μm thick sensitive layer, is combined with a stepped array of absorber films of the same thickness to produce a high-resolution depth-dose profile on the Gafchromic film. The depth-dose profile obtained in this manner has about five times greater resolution than conventional radiochromic film dosimetry. (author)

Quantum radiation reaction in head-on laser-electron beam interaction

International Nuclear Information System (INIS)

Vranic, Marija; Grismayer, Thomas; Fonseca, Ricardo A; Silva, Luis O

2016-01-01

In this paper, we investigate the evolution of the energy spread and the divergence of electron beams while they interact with different laser pulses at intensities where quantum effects and radiation reaction are of relevance. The interaction is modelled with a quantum electrodynamic (QED)-PIC code and the results are compared with those obtained using a standard PIC code with a classical radiation reaction module. In addition, an analytical model is presented that estimates the value of the final electron energy spread after the interaction with the laser has finished. While classical radiation reaction is a continuous process, in QED, radiation emission is stochastic. The two pictures reconcile in the limit when the emitted photons energy is small compared to the energy of the emitting electrons. The energy spread of the electron distribution function always tends to decrease with classical radiation reaction, whereas the stochastic QED emission can also enlarge it. These two tendencies compete in the QED-dominated regime. Our analysis, supported by the QED module, reveals an upper limit to the maximal attainable energy spread due to stochasticity that depends on laser intensity and the electron beam average energy. Beyond this limit, the energy spread decreases. These findings are verified for different laser pulse lengths ranging from short ∼30 fs pulses presently available to the long ∼150 fs pulses expected in the near-future laser facilities, and compared with a theoretical model. Our results also show that near future experiments will be able to probe this transition and to demonstrate the competition between enhanced QED induced energy spread and energy spectrum narrowing from classical radiation reaction. (paper)

Application of gypsum as shielding against low-energy X-radiation in the radiodiagnosis area

International Nuclear Information System (INIS)

Lins, J.A.G.; Lima, F.R.A.; Santos, M.A.P. dos; Oliveira, D.N.S. de; Silva, V.H.F.F. da

2017-01-01

In recent years, materials such as lead, concrete and iron have been studied for use as shielding for ionizing radiations of different energies in radiative installations. In the radiodiagnosis area, lead and barite are the most used materials as shielding. However, for beams of low energy X-radiation, such as in mammography and dentistry, the gypsum material may be used. This study aims to verify the feasibility of the use of gypsum as shielding for low-energy X-ray using standardized dental X-ray beams in a metrology laboratory. The project will allow a better understanding in the study of gypsum used as shielding, certifying its use as a good attenuator for low-energy X-ray

Spectral and kinetic analysis of radiation induced optical attenuation in silica: towards intrinsic fibre optic dosimetry?

International Nuclear Information System (INIS)

Borgermans, P.

2002-01-01

The document is an abstract of a PhD thesis. The PhD work concerns the detailed investigation of the behaviour of optical fibres in radiation fields such as is the case for various nuclear and space application,s. The core of the work concerns the spectral and kinetic analysis of the radiation induced optical attenuation. Models describing underlying physical phenomena, both for the spectral and the time dimensions, have been developed. The potential of silica optical fibre waveguides for intrinsic dosimetry has been assessed by employing specific properties of radiation induced defects in the silica waveguide material

Attenuation of radiological consequences from CDA's by radiation. Progress report, October 1, 1976--September 31, 1977

International Nuclear Information System (INIS)

Chan, S.H.

1977-01-01

This technical progress report summarizes the research work accomplished during the first six months of the investigation on the significance of radiation heat transfer in attenuating the radiological consequences from LMFBR core disruptive accidents. Considerable progress has been made in modeling and computing the effects of radiative cooling on a rising HCDA bubble buoyant through a sodium pool. Our results reveal that most of the fuel vapor within the bubble can be effectively condensed out by radiating cooling. The finding has a profound implication as it could lead to a substantial reduction in subsequent aerosal releases

Experiment for dose measurement during beam killing at Indus-1 synchrotron radiation source

International Nuclear Information System (INIS)

Nayak, M.K.; Dev, Vipin; Haridas, G.; Thakkar, K.K.; Sarkar, P.K.; Sharma, D.N.

2006-01-01

Experimental measurement of radiation dose likely to be received by an occupational worker in the experimental hall of Indus-1 during accidental beam killing was carried out. Various accidental beam-killing scenarios were experimentally simulated for the measurement. The measurement was carried out using direct reading dosimeters. Result shows that in the event of accidental beam killing, dose likely to be received by an occupational worker outside the shield is negligible. (author)

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

Dosimetric characterization of BeO samples in alpha, beta and X radiation beams using luminescent techniques

International Nuclear Information System (INIS)

Groppo, Daniela Piai

2013-01-01

In the medical field, the ionizing radiation is used both for therapeutic and diagnostic purposes, in a wide range of radiation doses. In order to ensure that the objective is achieved in practice, detailed studies of detectors and devices in different types of radiations beams are necessary. In this work a dosimetric characterization of BeO samples was performed using the techniques of thermoluminescence (TL) and optically stimulated luminescence (OSL) by a comparison of their response for alpha, beta and X radiations and the establishment of an appropriated system for use in monitoring of these radiations beams. The main results are: the high sensitivity to beta radiation for both techniques, good reproducibility of TL and OSL response (coefficients of variation lower than 5%), maximum energy dependence of the X radiation of 28% for the TL technique, and only 7% for the OSL technique, within the studied energy range. The dosimetric characteristics obtained in this work show the possibility of applying BeO samples to dosimetry of alpha, beta and X radiations, considering the studied dose ranges, using the TL and OSL techniques. From the results obtained, the samples of BeO showed their potential use for beam dosimetry in diagnostic radiology and radiotherapy. (author)

Electromagnetic radiation and nonlinear energy flow in an electron beam-plasma system

Science.gov (United States)

Whelan, D. A.; Stenzel, R. L.

1985-01-01

It is shown that the unstable electron-plasma waves of a beam-plasma system can generate electromagnetic radiation in a uniform plasma. The generation mechanism is a scattering of the unstable electron plasma waves off ion-acoustic waves, producing electromagnetic waves whose frequency is near the local plasma frequency. The wave vector and frequency matching conditions of the three-wave mode coupling are experimentally verified. The electromagnetic radiation is observed to be polarized with the electric field parallel to the beam direction, and its source region is shown to be localized to the unstable plasma wave region. The frequency spectrum shows negligible intensity near the second harmonic of the plasma frequency. These results suggest that the observed electromagnetic radiation of type III solar bursts may be generated near the local plasma frequency and observed downstream where the wave frequency is near the harmonic of the plasma frequency.

The effect of a metal hip prosthesis on the radiation dose in therapeutic photon beam irradiations

Energy Technology Data Exchange (ETDEWEB)

Lin, S.-Y.; Chu, T.-C. E-mail: tcchu@mx.nthu.edu.tw; Lin, J.-P.; Liu, M.-T

2002-07-01

Prostate and cervical cancer patients are often treated with external X-ray beams of bi-lateral incidence. Such treatment may incur some dose effect that cannot be predicted precisely in commercial treatment planning systems (TPS) for patients having undergone total hip replacement. This study performs a Monte Carlo (MC) simulation and an analytical calculation (convolution superposition algorithm which is implemented in ADAC TPS) of a 6 MV, 5x5 cm{sup 2} X-ray beam incident into water with the existence of hip prosthesis, e.g. Ti6Al4V and CoCrMo alloy. The results indicate that ADAC TPS cannot precisely account for the scatter and backscatter radiation that a metal hip prosthesis causes. For percent depth dose (PDD) curves, the maximum underdosage of ADAC TPS up to 5 mm above the interface between dense material and water is 5%, 20% and 27% for PDD{sub Bone}, PDD{sub Ti} and PDD{sub Co}, respectively. The dose re-buildup, which occurs behind the hip region, becomes more and more obvious for denser medium existed in water. Increasing inhomogeneity also enhances the underdosage of ADAC for greater depth (>10 cm), as the figures of nearly 2% in PDD{sub Bone}, PDD{sub Ti} and 4-5% in PDD{sub Co} reveal. Overestimating the attenuated power of high-density non-water material in ADAC TPS causes this underdosage. For dose profiles, no significant differences were found in Profile{sub Bone} at any depth. Profile{sub Ti} reveals that MC slightly exceeds ADAC at off-axis position 1.0-2.0 cm. Profile{sub Co} reveals this more obviously. This finding means that scatter radiation from these denser materials is significant and cannot be predicted precisely in ADAC.

A novel diamond-based beam position monitoring system for the High Radiation to Materials facility at CERN SPS

CERN Document Server

AUTHOR|(CDS)2092886; Höglund, Carina

The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, alb...

Nonlinear effects in the radiation force generated by amplitude-modulated focused beams

Science.gov (United States)

González, Nuria; Jiménez, Noé; Redondo, Javier; Roig, Bernardino; Picó, Rubén; Sánchez-Morcillo, Víctor; Konofagou, Elisa E.; Camarena, Francisco

2012-10-01

Harmonic Motion Imaging (HMI) uses an amplitude-modulated (AM) beam to induce an oscillatory radiation force before, during and after ablation. In this paper, the findings from a numerical analysis of the effects related with the nonlinear propagation of AM focused ultrasonic beams in water on the radiation force and the location of its maxima will be presented. The numerical modeling is performed using the KZK nonlinear parabolic equation. The radiation force is generated by a focused transducer with a gain of 18, a carrier frequency of 1 MHz and a modulation frequency of 25 kHz. The modulated excitation generates a spatially-invariant force proportional to the intensity. Regarding the nonlinear wave propagation, the force is no longer proportional to the intensity, reaching a factor of eight between the nonlinear and linear estimations. Also, a 9 mm shift in the on-axis force peak occurs when the initial pressure increased from 1 to 300 kPa. This spatial shift, due to the nonlinear effects, becomes dynamic in AM focused beams, as the different signal periods have different amplitudes. This study shows that both the value and the spatial position of the force peak are affected by the nonlinear propagation of the ultrasonic waves.

Monte Carlo calculation of scattered radiation from applicators in low energy clinical electron beams

International Nuclear Information System (INIS)

Jabbari, N.; Hashemi-Malayeri, B.; Farajollahi, A. R.; Kazemnejad, A.

2007-01-01

In radiotherapy with electron beams, scattered radiation from an electron applicator influences the dose distribution in the patient. The contribution of this radiation to the patient dose is significant, even in modern accelerators. In most of radiotherapy treatment planning systems, this component is not explicitly included. In addition, the scattered radiation produced by applicators varies based on the applicator design as well as the field size and distance from the applicators. The aim of this study was to calculate the amount of scattered dose contribution from applicators. We also tried to provide an extensive set of calculated data that could be used as input or benchmark data for advanced treatment planning systems that use Monte Carlo algorithms for dose distribution calculations. Electron beams produced by a NEPTUN 10PC medical linac were modeled using the BEAMnrc system. Central axis depth dose curves of the electron beams were measured and calculated, with and without the applicators in place, for different field sizes and energies. The scattered radiation from the applicators was determined by subtracting the central axis depth dose curves obtained without the applicators from that with the applicator. The results of this study indicated that the scattered radiation from the electron applicators of the NEPTUN 10PC is significant and cannot be neglected in advanced treatment planning systems. Furthermore, our results showed that the scattered radiation depends on the field size and decreases almost linearly with depth. (author)

Evaluation of a GEM and CAT-based detector for radiation therapy beam monitoring

International Nuclear Information System (INIS)

Brahme, A.; Danielsson, M.; Iacobaeus, C.; Ostling, J.; Peskov, V.; Wallmark, M.

2000-01-01

We are developing a radiation therapy beam monitor for the Karolinska Institute. This monitor will consist of two consecutive detectors confined in one gas chamber: a 'keV-photon detector', which will allow diagnostic quality visualization of the patient, and a 'MeV-photon detector', that will measure the absolute intensity of the therapy beam and its position with respect to the patient. Both detectors are based on highly radiation resistant gas and solid photon to electron converters, combined with GEMs and a CAT as amplification structures. We have performed systematic studies of the high-rate characteristics of the GEM and the CAT, as well as tested the electron transfer through these electron multipliers and various types of converters. The tests show that the GEM and the CAT satisfy all requirements for the beam monitoring system. As a result of these studies we successfully developed and tested a full section of the beam monitor equipped with a MeV-photon converter placed between the GEM and the CAT

Efficiency and attenuation correction factors determination in gamma spectrometric assay of bulk samples using self radiation

International Nuclear Information System (INIS)

Haddad, Kh.

2009-02-01

Gamma spectrometry forms the most important and capable tool for measuring radioactive materials. Determination of the efficiency and attenuation correction factors is the most tedious problem in the gamma spectrometric assay of bulk samples. A new experimental and easy method for these correction factors determination using self radiation was proposed in this work. An experimental study of the correlation between self attenuation correction factor and sample thickness and its practical application was also introduced. The work was performed on NORM and uranyl nitrate bulk sample. The results of proposed methods agreed with those of traditional ones.(author)

External-beam radiation therapy after surgical resection and intraoperative electron-beam radiation therapy for oligorecurrent gynecological cancer. Long-term outcome

International Nuclear Information System (INIS)

Sole, C.V.; Calvo, F.A.; Lozano, M.A.; Gonzalez-Sansegundo, C.; Gonzalez-Bayon, L.; Alvarez, A.; Lizarraga, S.; Garcia-Sabrido, J.L.

2014-01-01

The goal of the present study was to analyze prognostic factors in patients treated with external-beam radiation therapy (EBRT), surgical resection and intraoperative electron-beam radiotherapy (IOERT) for oligorecurrent gynecological cancer (ORGC). From January 1995 to December 2012, 61 patients with ORGC [uterine cervix (52 %), endometrial (30 %), ovarian (15 %), vagina (3 %)] underwent IOERT (12.5 Gy, range 10-15 Gy), and surgical resection to the pelvic (57 %) and paraaortic (43 %) recurrence tumor bed. In addition, 29 patients (48 %) also received EBRT (range 30.6-50.4 Gy). Survival outcomes were estimated using the Kaplan-Meier method, and risk factors were identified by univariate and multivariate analyses. Median follow-up time for the entire cohort of patients was 42 months (range 2-169 months). The 10-year rates for overall survival (OS) and locoregional control (LRC) were 17 and 65 %, respectively. On multivariate analysis, no tumor fragmentation (HR 0.22; p = 0.03), time interval from primary tumor diagnosis to locoregional recurrence (LRR) < 24 months (HR 4.02; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.95; p = 0.02) retained significance with regard to LRR. Time interval from primary tumor to LRR < 24 months (HR 2.32; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.77; p = 0.04) showed a significant association with OS after adjustment for other covariates. External-beam radiation therapy at the time of pelvic recurrence, time interval for relapse ≥24 months and not multi-involved fragmented resection specimens are associated with improved LRC in patients with ORGC. As suggested from the present analysis a significant group of ORGC patients could potentially benefit from multimodality rescue treatment. (orig.)

External-beam radiation therapy after surgical resection and intraoperative electron-beam radiation therapy for oligorecurrent gynecological cancer. Long-term outcome

Energy Technology Data Exchange (ETDEWEB)

Sole, C.V. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Instituto de Radiomedicina, Service of Radiation Oncology, Santiago (Chile); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Calvo, F.A. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Lozano, M.A.; Gonzalez-Sansegundo, C. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Service of Radiation Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Gonzalez-Bayon, L. [Hospital General Universitario Gregorio Maranon, Service of General Surgery, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Alvarez, A. [Hospital General Universitario Gregorio Maranon, Service of Radiation Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Lizarraga, S. [Hospital General Universitario Gregorio Maranon, Department of Gynecology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Garcia-Sabrido, J.L. [Complutense University, School of Medicine, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Service of General Surgery, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Department of Gynecology, Madrid (Spain)

2014-02-15

The goal of the present study was to analyze prognostic factors in patients treated with external-beam radiation therapy (EBRT), surgical resection and intraoperative electron-beam radiotherapy (IOERT) for oligorecurrent gynecological cancer (ORGC). From January 1995 to December 2012, 61 patients with ORGC [uterine cervix (52 %), endometrial (30 %), ovarian (15 %), vagina (3 %)] underwent IOERT (12.5 Gy, range 10-15 Gy), and surgical resection to the pelvic (57 %) and paraaortic (43 %) recurrence tumor bed. In addition, 29 patients (48 %) also received EBRT (range 30.6-50.4 Gy). Survival outcomes were estimated using the Kaplan-Meier method, and risk factors were identified by univariate and multivariate analyses. Median follow-up time for the entire cohort of patients was 42 months (range 2-169 months). The 10-year rates for overall survival (OS) and locoregional control (LRC) were 17 and 65 %, respectively. On multivariate analysis, no tumor fragmentation (HR 0.22; p = 0.03), time interval from primary tumor diagnosis to locoregional recurrence (LRR) < 24 months (HR 4.02; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.95; p = 0.02) retained significance with regard to LRR. Time interval from primary tumor to LRR < 24 months (HR 2.32; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.77; p = 0.04) showed a significant association with OS after adjustment for other covariates. External-beam radiation therapy at the time of pelvic recurrence, time interval for relapse ≥24 months and not multi-involved fragmented resection specimens are associated with improved LRC in patients with ORGC. As suggested from the present analysis a significant group of ORGC patients could potentially benefit from multimodality rescue treatment. (orig.)

Transverse phase space mapping of relativistic electron beams using optical transition radiation

Directory of Open Access Journals (Sweden)

G. P. Le Sage

1999-12-01

Full Text Available Optical transition radiation (OTR has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique.

Barium-borate-flyash glasses: As radiation shielding materials

International Nuclear Information System (INIS)

Singh, Sukhpal; Kumar, Ashok; Singh, Devinder; Thind, Kulwant Singh; Mudahar, Gurmel S.

2008-01-01

The attenuation coefficients of barium-borate-flyash glasses have been measured for γ-ray photon energies of 356, 662, 1173 and 1332 keV using narrow beam transmission geometry. The photon beam was highly collimated and overall scatter acceptance angle was less than 3 o . Our results have an uncertainty of less than 3%. These coefficients were then used to obtain the values of mean free path (mfp), effective atomic number and electron density. Good agreements have been observed between experimental and theoretical values of these parameters. From the studies of the obtained results it is reported here that from the shielding point of view the barium-borate-flyash glasses are better shields to γ-radiations in comparison to the standard radiation shielding concretes and also to the ordinary barium-borate glasses

Performance of a prototype of an extrapolation minichamber in various radiation beams

International Nuclear Information System (INIS)

Oliveira, M.L.; Caldas, L.V.E.

2007-01-01

An extrapolation minichamber was developed for measuring doses from weakly penetrating types of radiation. The chamber was tested at the radiotherapeutic dose level in a beam from a 90 Sr+ 90 Y check source, in a beam from a plane 90 Sr+ 90 Y ophthalmic applicator, and in several reference beams from an X-ray tube. Saturation, ion collection efficiency, stabilization time, extrapolation curves, linearity of chamber response vs. air kerma rate, and dependences of the response on the energy and irradiation angle were characterized. The results are satisfactory; they show that the chamber can be used in the dosimetry of 90 Sr+ 90 Y beta particles and low-energy X-ray beams

Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays.

Science.gov (United States)

Zygmanski, Piotr; Sajo, Erno

2016-01-01

We review radiation transport and clinical beam modelling for gold nanoparticle dose-enhanced radiotherapy using X-rays. We focus on the nanoscale radiation transport and its relation to macroscopic dosimetry for monoenergetic and clinical beams. Among other aspects, we discuss Monte Carlo and deterministic methods and their applications to predicting dose enhancement using various metrics.

Radiation disinfestation of used packagings: irradiation trials with electron beams

International Nuclear Information System (INIS)

Ignatowicz, S.; Zaedee, I.

1994-01-01

Used bags, sacks and other packagings are often infested with insects and mites - pest of stored products. Such packagings provide a source of infestation of a new lot or unit of agricultural products. Cleaning of repeatedly used packages is the most important preventive method. After using, the bags and sacks should be carefully beaten with a mechanical or hand beater. When pests are found, the packages should be disinfested with hot air or hot water. Larger numbers of bags are usually fumigated in a special fumigation chamber. Disinfestation by radiation processing is potentially a feasible substitute for chemical fumigation. In the present paper trials of radiation disinfestation of used bags are described and discussed. Information about using electron beams for pest disinfestation of jute and polyvinyl chloride bags (plastic bags) is provided. The absorbed dose is the most important irradiation process parameter. The lethal effects equivalent to chemical insecticides are obtained by high doses of ionizing radiation. Control of insect and/or mite infestation of the repeatedly used packagings may be secured by ionizing radiation applied at 2-3 kGy. These doses result in complete mortality of stored product pests within a few days. The radiation must penetrate deeply into the target product at sufficient level. Gamma rays and X-rays penetrate into the treated products easily but electron radiation penetrating is much lower, depending on electron energy applied. The results of this study indicate that bags made of polyvinyl chloride may be disinfested with electron beams when are created as separate units or batches up to 50 bags. Penetrability of jute bags is lower than the plastic bags. Therefore the jute bags should be irradiated with electrons as batches containing no more than 30 bags. (author)

Analysis of biological samples by x-ray attenuation measurements

International Nuclear Information System (INIS)

Cesareo, R.

1988-01-01

Over the last few years there has been an increasing interest in X-ray attenuation measurements, mainly due to the enormous development of computer assisted tomography (CAT). With CAT, analytical information concerning the density and the mean atomic number distributions in a sample is deduced from a large number of attenuation measurements. Particular transmission methods developed, based on the differential attenuation method are discussed. The theoretical background for attenuation of radiation and for differential attenuation of radiation is given. Details about the generation of monoenergetic X-rays are discussed. Applications of attenuation measurements in the field of Medicine are presented

Protein crystallography with a micrometre-sized synchrotron-radiation beam

International Nuclear Information System (INIS)

Moukhametzianov, Rouslan; Burghammer, Manfred; Edwards, Patricia C.; Petitdemange, Sebastien; Popov, Dimitri; Fransen, Maikel; McMullan, Gregory; Schertler, Gebhard F. X.; Riekel, Christian

2008-01-01

For the first time, protein microcrystallography has been performed with a focused synchrotron-radiation beam of 1 µm using a goniometer with a sub-micrometre sphere of confusion. The crystal structure of xylanase II has been determined with a flux density of about 3 × 10 10 photons s −1 µm −2 at the sample. For the first time, protein microcrystallography has been performed with a focused synchrotron-radiation beam of 1 µm using a goniometer with a sub-micrometre sphere of confusion. The crystal structure of xylanase II has been determined with a flux density of about 3 × 10 10 photons s −1 µm −2 at the sample. Two sets of diffraction images collected from different sized crystals were shown to comprise data of good quality, which allowed a 1.5 Å resolution xylanase II structure to be obtained. The main conclusion of this experiment is that a high-resolution diffraction pattern can be obtained from 20 µm 3 crystal volume, corresponding to about 2 × 10 8 unit cells. Despite the high irradiation dose in this case, it was possible to obtain an excellent high-resolution map and it could be concluded from the individual atomic B-factor patterns that there was no evidence of significant radiation damage. The photoelectron escape from a narrow diffraction channel is a possible reason for reduced radiation damage as indicated by Monte Carlo simulations. These results open many new opportunities in scanning protein microcrystallography and make random data collection from microcrystals a real possibility, therefore enabling structures to be solved from much smaller crystals than previously anticipated as long as the crystallites are well ordered

Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

International Nuclear Information System (INIS)

Oothoudt, M.; Pillai, C.; Zumbro, M.

1997-01-01

Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances

High-radiation zone design of the FMIT high-density beam transport

International Nuclear Information System (INIS)

Creek, K.O.; Liska, D.J.; King, J.D.; Cole, T.R.; Cimabue, A.G.; Robeson, L.P.; Harvey, A.

1981-03-01

The Fusion Materials Irradiation Test (FMIT) deuteron linac, operating at 35 MeV and 100 mA continuous duty, is expected to spill 3 μA/m and to lose 10 μA at specific bending-magnet positions. The major impact of this spill will be felt in the High-Energy Beam Transport (HEBT), where many beam-line components must be maintained. A modular design concept, that uses segmented termination panels remotely located from the modules, is being employed. Radiation-hardened quadrupoles can be opened, clam-shell fashion, to release the water-cooled beam tube r replacement if there is beam damage or lithium contamination from the target. Termination panels contain electrical, water, and instrumentation fittings to service the module, and are positioned to allow room for neutron-absorbing shielding between the beamline and the panel. The modular construction allows laboratory prealignment and check-out of all components on a structural carriage and is adaptable to supporting gamma shields. Proper choice of beam tube materials is essential for controlling activation caused by beam spill

Radiation vulcanization of natural rubber latex using 250 keV electron beam machine

Energy Technology Data Exchange (ETDEWEB)

Chirinos, H.; Yoshii, F.; Makuuchi, K.; Lugao, A. E-mail: ablugao@net.ipen.br

2003-08-01

The sensitized radiation vulcanization of natural rubber latex has been carried out with 250 keV electrons. Latex was irradiated over a range of the beam current from 5 to 20 mA in the presence of sensitizers like the n-butyl acrylate (n-BA). The vulcanization dose decreases with increasing beam current condition. The rate of vulcanization (R{sub vul}) depends on the beam current (I) as given by the equation R{sub vul}=kI{sup 0.6}.

Effect of Photon Beam Energy, Gold Nanoparticle Size and Concentration on the Dose Enhancement in Radiation Therapy

Directory of Open Access Journals (Sweden)

Nahideh Gharehaghaji

2013-02-01

Full Text Available Introduction: Gold nanoparticles have been used as radiation dose enhancing materials in recent investigations. In the current study, dose enhancement effect of gold nanoparticles on tumor cells was evaluated using Monte Carlo (MC simulation. Methods: We used MCNPX code for MC modeling in the current study. A water phantom and a tumor region with a size of 1×1×1 cm3 loaded with gold nanoparticles were simulated. The macroscopic dose enhancement factor was calculated for gold nanoparticles with sizes of 30, 50, and 100 nm. Also, we simulated different photon beams including mono-energetic beams (50-120 keV, a Cobalt-60 beam, 6 & 18 MV photon beams of a conventional linear accelerator. Results: We found a dose enhancement factor (DEF of from 1.4 to 3.7 for monoenergetic kilovoltage beams, while the DEFs for megavoltage beams were negligible and less than 3% for all GNP sizes and concentrations. The optimum energy for higher DEF was found to be the 90 keV monoenergetic beam. The effect of GNP size was not considerable, but the GNP concentration had a substantial impact on achieved DEF in GNP-based radiation therapy. Conclusion: The results were in close agreement with some previous studies considering the effect of photon energy and GNP concentration on observed DEF. Application of GNP-based radiation therapy using kilovoltage beams is recommended.

Response of TLD-100"T"M microtubes to two RQR3 quality radiation beams

International Nuclear Information System (INIS)

Nunes, M.G.; Villani, D.; Almeida, S.B.; Vivolo, V.; Yoriyaz, H.; Louis, G.M.J.

2016-01-01

The present work compares the response of TLD-100"T"M microcubes to two RQR 3 diagnostic radiology reference quality radiation beams, defined by IEC-61267 norm, aiming to evaluate the detectability of TLD-100"T"M energy dependence reported in literature within the same reference quality radiation range. TLD-100"T"M microcubes reproducibility is assessed through the response of a second set of TLD-100"T"M microcubes, evaluated in a second thermoluminescence reader, to the RQR 3 diagnostic radiology reference quality radiation beam implemented at the Laboratorio de Calibracao de Instrumentos of IPEN, Sao Paulo, SP, Brazil. The dependence of TLD-100"T"M microcubes TL response was not detectable in these conditions and the reproducibility of the measurements is 90,2%. (author)

Coronary cineangiography and ionizing radiation exposure to patients: analysis of primary and secondary beam

International Nuclear Information System (INIS)

Ramirez, Alfredo; Leyton, Fernando; Silva, Ana Maria; Farias, Eric

2001-01-01

The purpose of this work was to determine the level of exposure dose to patients during coronariographies in different areas of body. This study has presented the medical surveillance of 18 cases and the radiation monitoring of these patients by TLD in thyroid and pelvis (secondary beam) and, in the right and left scapular region (primary beam) for each one of these procedures. The ionizing radiation received was 215 ± 200 mGy in left scapular region (range 1-710) and 255±213 mGy in the right scapular region (range 22-635) p=NS. In the pelvic region the ionizing radiation was 0,22±0,06 mGy and in the thyroid region was 3,62±2,44 mGy

First measurements of subpicosecond electron beam structure by autocorrelation of coherent diffraction radiation

CERN Document Server

Lumpkin, Alex H; Rule, D W

2001-01-01

We report the initial measurements of subpicosecond electron beam structure using a nonintercepting technique based on the autocorrelation of coherent diffraction radiation (CDR). A far infrared (FIR) Michelson interferometer with a Golay detector was used to obtain the autocorrelation. The radiation was generated by a thermionic rf gun beam at 40 MeV as it passed through a 5-mm-tall slit/aperture in a metal screen whose surface was at 45 deg. to the beam direction. For the observed bunch lengths of about 450 fs (FWHM) with a shorter time spike on the leading edge, peak currents of about 100 A are indicated. Also a model was developed and used to calculate the CDR from the back of two metal strips separated by a 5-mm vertical gap. The demonstrated nonintercepting aspect of this method could allow on-line bunch length characterizations to be done during free-electron laser experiments.

Very small beam-size measurement by a reflective synchrotron radiation interferometer

Directory of Open Access Journals (Sweden)

T. Naito

2006-12-01

Full Text Available A synchrotron radiation (SR interferometer with Herschelian reflective optics has been developed for the measurement of beams of several μm in size. In a conventional refractive SR interferometer, the dispersion effect of the objective lens limits the instrument to a smaller range of beam-size measurements. To avoid this problem, we designed a Herschelian arrangement of reflective optics for the interferometer. The effectiveness of the reflective SR interferometer was confirmed at the KEK Accelerator Test Facility (ATF damping ring. The measured vertical beam size obtained using the reflective SR interferometer was 4.7   μm and the estimated vertical emittance was 0.97×10^{-11}   m.

BEAM applications to polymer materials

International Nuclear Information System (INIS)

Tagawa, Seiichi

1994-01-01

Recently papers about beam applications to polymers have been increasing rapidly both in the fundamental and applied fields. Fairly large number of papers have been published in the fundamental aspects of radiation effects of beam applications to polymers such as pulse radiolysis and high density electronic excitation effects. A number of papers have been published in the more applied aspects of beam applications to polymers such as radiation processing and curing. The present paper describes recent beam applications to polymers. 1. Radiation Effects on Polymers; Radiation effects on polymers have been studied for more than 40 years. Most of work on radiation effects on polymers has been carried out by using high energy photon (gamma-ray) and electron beams, since polymers are sensitive to any kinds of ionizing radiation. Even non-ionizing radiation such as ultraviolet and visible light excites electronic excited states of polymers and then photo-chemical reactions of polymers are induced from the electronic excited states. Studies on radiation effects of other ionizing radiation on polymers have not been so popular for a long time. Recently application of new radiation such as ion beams to polymers have been worthy of remark in fields of advanced science and technology, since new radiation beams induce different radiation effects from those induced by high energy gamma-rays and electrons. 2. Beam Applications of Polymers; Recent progress in beam applications to polymers such as radiation processing and curing, x-ray and electron beam microlithography, and applications of new beams such as ion beams to polymers has been reviewed. (author)

Quality control methodology and implementation of X-radiation standards beams, mammography level, following the standard IEC 61267

International Nuclear Information System (INIS)

Correa, Eduardo de Lima

2010-01-01

In this work it was developed and applied a quality control program of the X radiation system (160 kV, constant potential, target of tungsten) of the Calibration Laboratory of IPEN(LCI) in the energy range relative to mammography beams (from 25 kV to 35 kV). The X radiation standards beams, level mammography, using molybdenum and aluminum as additional filtration, were established after the application of this quality control program following national and international recommendations. The reference ionization chamber has traceability to PTB and was regularly submitted to quality control tests for evaluation and analysis of its performance. The radiation qualities emerging from the X-radiation assembly (RQR-M), based on a phantom made up of an aluminum added filter (RQA-M), narrow beam condition (RQN-M) and broad beam condition (RQB-M), following the recommendations of the international standard IEC 61267 (2005) and the IAEA code of practice, TRS 457 (2007) were established. For the implantation of RQN-M and RQB-M radiation qualities, two mammography phantoms were developed. The half-value layers found are those presented by the German primary laboratory PTB, and varied from 0.35 to 1.21 mm Al. The air kerma rates were obtained for all the 15 implanted qualities. (author)

Evaluation of the spectral distribution of X-ray beams from measurements on the scattered radiation

International Nuclear Information System (INIS)

Casnati, E.; Baraldi, C.

1980-01-01

Most of the phenomena activated by photons with energies below 100 keV show an apparent or real dependence on the quantum energy. Therefore, knowledge of the beam energy characteristics is of primary importance for interpretation of the irradiation results. The greatest difficulty arises from the high flux density of the beams usually employed which does not allow direct measurements of the beam. A method was developed which permits evaluation of the spectral distribution of the X-ray beam from a spectrometric measurement of the radiation scattered by a thin foil of a suitable metal. This makes possible a new and more rational approach to the measurement of X-rays in the energy range where the interaction parameters show a large photon energy dependence. The corrections required by the presence of some collateral effects, among which the most important is the coexistence of the coherent and incoherent scattering, must be evaluated. The knowledge of the spectral distribution is of immediate usefulness for studies of radiation damage in biological and other materials, for the calibration of radiation measuring instruments and for the improvement of the radiological instrumentation response which contributes to reducing the patient's dose. (H.K.)

Target size analysis of bioactive substances by radiation inactivation. Comparison with electron beam and. gamma. -ray

Energy Technology Data Exchange (ETDEWEB)

Kume, Tamikazu; Watanabe, Yuhei; Ishigaki, Isao; Hirose, Shigehisa

1988-11-01

The molecular sizes of various bioactive substances can be measured by the radiation inactivation method. The high energy electron beam (10 MeV) and /sup 60/Co-..gamma.. ray are mainly used for radiation inactivation method. When the practical electron accelerator (/similar to/ 3 MeV) is used for the method, the problems such as penetration and increase of temperature will arise. In this paper the radiation inactivation using 3MeV electron beam is investigated by comparison with ..gamma..-ray. When the plate type glass ampules (glass thickness 1 +- 0.1 mm) were used as the irradiation vessels, relatively uniform dose distribution was obtained. The temperature increased only from 21 degC to 35 degC by irradiation (0.77 mA, 100 passes, 100 kGy). Under the irradiation condition mentioned above, the molecular size of three enzymes were calculated from D/sub 37/ doses. The molecular sizes obtained by electron beam and ..gamma..-ray were 14,000 and 17,000 respectively for lysozyme, 33,000 for pepsin, and 191,000 and 164,000 for yeast alcohol dehydrogenase. These values agreed closely with the reported molecular weight, suggesting that the 3 MeV electron beam can also be used for the radiation inactivation under limited conditions.

Visualizing Electron Beam Dynamics and Instabilities with Synchrotron Radiation at the APS

CERN Document Server

Yang Bing Xin

2005-01-01

The Advanced Photon Source (APS) is a third generation hard x-ray source serving a large user community. In order to characterize the high-brilliance beams, the APS diagnostics beamlines have been developed into a full photon diagnostics suite. We will describe the design and capabilities of the APS visible light imaging line, the bend magnet x-ray pinhole camera, and a unique diagnostics undulator beamline. Their primary functions are to support the APS user operations by providing information on beam sizes (20 - 100 micrometers), divergence (3 – 25 microradians), and bunch length (20 – 50 ps). Through the use of examples, we will show how these complementary imaging tools are used to visualize the electron dynamics and investigate beam instabilities. Special emphasis will be put on the use of undulator radiation, which is uniquely suitable for time-resolved imaging of electron beam with high spatial resolution, and for measurements of longitudinal beam properties such as beam energy spread...

Simulation of 3-D radiation beam patterns propagated through a planar interface from ultrasonic phased array transducers.

Science.gov (United States)

Song, Sung-Jin; Kim, Chang-Hwan

2002-05-01

Phased array transducers are quite often mounted on solid wedges with specific angles in many practical ultrasonic inspections of thin plates phased array techniques with testing set-up, it is essential to have thorough understanding on the characteristics of radiation beam pattern produced in the interrogated medium. To address such a need, this paper proposes a systematic way to calculate full 3-D radiation beam patterns produced in the interrogated solid medium by phased array transducers mounted on a solid wedge. In order to investigate the characteristics of radiation beam patterns in steel, simulation is carried out for 7.5 MHz array transducers mounted on an acrylic wedge with the angle of 15.45 degrees with various of steering angles and/or focal planes.

High-energy coherent terahertz radiation emitted by wide-angle electron beams from a laser-wakefield accelerator

Science.gov (United States)

Yang, Xue; Brunetti, Enrico; Jaroszynski, Dino A.

2018-04-01

High-charge electron beams produced by laser-wakefield accelerators are potentially novel, scalable sources of high-power terahertz radiation suitable for applications requiring high-intensity fields. When an intense laser pulse propagates in underdense plasma, it can generate femtosecond duration, self-injected picocoulomb electron bunches that accelerate on-axis to energies from 10s of MeV to several GeV, depending on laser intensity and plasma density. The process leading to the formation of the accelerating structure also generates non-injected, sub-picosecond duration, 1–2 MeV nanocoulomb electron beams emitted obliquely into a hollow cone around the laser propagation axis. These wide-angle beams are stable and depend weakly on laser and plasma parameters. Here we perform simulations to characterise the coherent transition radiation emitted by these beams if passed through a thin metal foil, or directly at the plasma–vacuum interface, showing that coherent terahertz radiation with 10s μJ to mJ-level energy can be produced with an optical to terahertz conversion efficiency up to 10‑4–10‑3.

Maximum dose angle for oblique incidence on primary beam protective barriers in the design of medical radiation therapy facilities

International Nuclear Information System (INIS)

Fondevila, Damian; Arbiser, Silvio; Sansogne, Rosana; Brunetto, Monica; Dosoretz, Bernardo

2008-01-01

Primary barrier determinations for the shielding of medical radiation therapy facilities are generally made assuming normal beam incidence on the barrier, since this is geometrically the most unfavorable condition for that shielding barrier whenever the occupation line is allowed to run along the barrier. However, when the occupation line (for example, the wall of an adjacent building) runs perpendicular to the barrier (especially roof barrier), then two opposing factors come in to play: increasing obliquity angle with respect to the barrier increases the attenuation, while the distance to the calculation point decreases, hence, increasing the dose. As a result, there exists an angle (α max ) for which the equivalent dose results in a maximum, constituting the most unfavorable geometric condition for that shielding barrier. Based on the usual NCRP Report No. 151 model, this article presents a simple formula for obtaining α max , which is a function of the thickness of the barrier (t E ) and the equilibrium tenth-value layer (TVL e ) of the shielding material for the nominal energy of the beam. It can be seen that α max increases for increasing TVL e (hence, beam energy) and decreases for increasing t E , with a range of variation that goes from 13 to 40 deg for concrete barriers thicknesses in the range of 50-300 cm and most commercially available teletherapy machines. This parameter has not been calculated in the existing literature for radiotherapy facilities design and has practical applications, as in calculating the required unoccupied roof shielding for the protection of a nearby building located in the plane of the primary beam rotation

Maximum dose angle for oblique incidence on primary beam protective barriers in the design of medical radiation therapy facilities.

Science.gov (United States)

Fondevila, Damián; Arbiser, Silvio; Sansogne, Rosana; Brunetto, Mónica; Dosoretz, Bernardo

2008-05-01

Primary barrier determinations for the shielding of medical radiation therapy facilities are generally made assuming normal beam incidence on the barrier, since this is geometrically the most unfavorable condition for that shielding barrier whenever the occupation line is allowed to run along the barrier. However, when the occupation line (for example, the wall of an adjacent building) runs perpendicular to the barrier (especially roof barrier), then two opposing factors come in to play: increasing obliquity angle with respect to the barrier increases the attenuation, while the distance to the calculation point decreases, hence, increasing the dose. As a result, there exists an angle (alpha(max)) for which the equivalent dose results in a maximum, constituting the most unfavorable geometric condition for that shielding barrier. Based on the usual NCRP Report No. 151 model, this article presents a simple formula for obtaining alpha(max), which is a function of the thickness of the barrier (t(E)) and the equilibrium tenth-value layer (TVL(e)) of the shielding material for the nominal energy of the beam. It can be seen that alpha(max) increases for increasing TVL(e) (hence, beam energy) and decreases for increasing t(E), with a range of variation that goes from 13 to 40 deg for concrete barriers thicknesses in the range of 50-300 cm and most commercially available teletherapy machines. This parameter has not been calculated in the existing literature for radiotherapy facilities design and has practical applications, as in calculating the required unoccupied roof shielding for the protection of a nearby building located in the plane of the primary beam rotation.

Treatment of Head and Neck Paragangliomas With External Beam Radiation Therapy

International Nuclear Information System (INIS)

Dupin, Charles; Lang, Philippe; Dessard-Diana, Bernadette; Simon, Jean-Marc; Cuenca, Xavier; Mazeron, Jean-Jacques; Feuvret, Loïc

2014-01-01

Purpose: To retrospectively assess the outcomes of radiation therapy in patients with head and neck paragangliomas. Methods and Materials: From 1990 to 2009, 66 patients with 81 head and neck paragangliomas were treated by conventional external beam radiation therapy in 25 fractions at a median dose of 45 Gy (range, 41.4-68 Gy). One case was malignant. The median gross target volume and planning target volume were 30 cm 3 (range, 0.9-243 cm 3 ) and 116 cm 3 (range, 24-731 cm 3 ), respectively. Median age was 57.4 years (range, 15-84 years). Eleven patients had multicentric lesions, and 8 had family histories of paraganglioma. Paragangliomas were located in the temporal bone, the carotid body, and the glomus vagal in 51, 18, and 10 patients, respectively. Forty-six patients had exclusive radiation therapy, and 20 had salvage radiation therapy. The median follow-up was 4.1 years (range, 0.1-21.2 years). Results: One patient had a recurrence of temporal bone paraganglioma 8 years after treatment. The actuarial local control rates were 100% at 5 years and 98.7% at 10 years. Patients with multifocal tumors and family histories were significantly younger (42 years vs 58 years [P=.002] and 37 years vs 58 years [P=.0003], respectively). The association between family predisposition and multifocality was significant (P<.001). Two patients had cause-specific death within the 6 months after irradiation. During radiation therapy, 9 patients required hospitalization for weight loss, nausea, mucositis, or ophthalmic zoster. Two late vascular complications occurred (middle cerebral artery and carotid stenosis), and 2 late radiation-related meningiomas appeared 15 and 18 years after treatment. Conclusion: Conventional external beam radiation therapy is an effective and safe treatment option that achieves excellent local control; it should be considered as a first-line treatment of choice for head and neck paragangliomas

Small Radiation Beam Dosimetry for Radiosurgery of Trigeminal Neuralgia: One Case Analysis

International Nuclear Information System (INIS)

Garcia-Garduno, O. A.; Larraga-Gutierrez, J. M.; Rodriguez-Villafuerte, M.; Martinez-Davalos, A.; Moreno-Jimenez, S.; Suarez-Campos, J. J.; Celis, M. A.

2008-01-01

The use of small radiation beams for trigeminal neuralgia (TN) treatment requires high precision and accuracy in dose distribution calculations and delivery. Special attention must be kept on the type of detector to be used. In this work, the use of GafChromic EBT registered radiochromic and X-OMAT V2 radiographic films for small radiation beam characterization is reported. The dosimetric information provided by the films (total output factors, tissue maximum ratios and off axis ratios) is compared against measurements with a shielded solid state (diode) reference detector. The film dosimetry was used for dose distribution calculations for the treatment of trigeminal neuralgia radiosurgery. Comparison of the isodose curves shows that the dosimetry produced with the X-OMAT radiographic film overestimates the dose distributions in the penumbra region

On radiation emission from a microbunched beam with wavefront tilt and its experimental observation

Energy Technology Data Exchange (ETDEWEB)

Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2017-06-15

In this paper we compare experimental observations and theory of radiation emission from a microbunched beam with microbunching wavefront tilt with respect to the direction of motion. The theory refers to the work of T. Tanaka, H. Kitamura, and T. Shintake (2004), which predicts, in this case, exponential suppression of coherent radiation along the kicked direction. The observations refer to a recent experiment performed at the LCLS, where a microbunched beam was kicked by a bend and sent to a radiator undulator. The experiment resulted in the emission of strong coherent radiation that had its maximum along the kicked direction of motion, when the undulator parameter was detuned to a value larger than the nominal one. We first analyze the theory in detail, and we confirm the correctness of its derivation according to the conventional theory of radiation emission from charged particles. Subsequently, we look for possible peculiarities in the experiment, which may not be modeled by the theory. We show that only spurious effects are not accounted for. We conclude that the experiment defies explanation in terms of the conventional theory of radiation emission.

On radiation emission from a microbunched beam with wavefront tilt and its experimental observation

Science.gov (United States)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2018-03-01

In this paper we compare experimental observations and theory of radiation emission from a microbunched beam with microbunching wavefront tilt with respect to the direction of motion. The theory refers to the work Tanaka et al. (2004) , which predicts, in this case, exponential suppression of coherent radiation along the kicked direction. The observations refer to a recent experiment performed at the LCLS (Nuhn et al., 2015; Lutman etal., 2016), where a microbunched beam was kicked by a bend and sent to a radiator undulator. The experiment resulted in the emission of strong coherent radiation that had its maximum along the kicked direction of motion, when the undulator parameter was detuned to a value larger than the nominal one. We first analyze the theory in detail, and we confirm the correctness of its derivation according to the conventional theory of radiation emission from charged particles. Subsequently, we look for possible peculiarities in the experiment, which may not be modeled by the theory. We show that only spurious effects are not accounted for. We conclude that the experiment defies explanation in terms of the conventional theory of radiation emission.

Lessons from shielding retrofits at the LAMPF/LANSCE/PSR accelerator, beam lines and target facilities

International Nuclear Information System (INIS)

Macek, R.J.

1994-01-01

The experience in the past 7 years to improve the shielding and radiation control systems at the Los Alamos Meson Physics Facility (LAMPF) and the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) provides important lessons for the design of radiation control systems at future, high beam power proton accelerator facilities. Major issues confronted and insight gained in developing shielding criteria and in the use of radiation interlocks are discussed. For accelerators and beam lines requiring hands-on-maintenance, our experience suggests that shielding criteria based on accident scenarios will be more demanding than criteria based on routinely encountered beam losses. Specification and analysis of the appropriate design basis accident become all important. Mitigation by active protection systems of the consequences of potential, but severe, prompt radiation accidents has been advocated as an alternate choice to shielding retrofits for risk management at both facilities. Acceptance of active protection systems has proven elusive primarily because of the difficulty in providing convincing proof that failure of active systems (to mitigate the accident) is incredible. Results from extensive shielding assessment studies are presented including data from experimental beam spill tests, comparisons with model estimates, and evidence bearing on the limitations of line-of-sight attenuation models in complex geometries. The scope and significant characteristics of major shielding retrofit projects at the LAMPF site are illustrated by the project to improve the shielding beneath a road over a multiuse, high-intensity beam line (Line D)

When and how should we teach the basic concepts of radiation beam dosage

International Nuclear Information System (INIS)

Brewin, T.B.

1977-01-01

The difficulty that many trainees, including those medically qualified, have in achieving a sound working grasp of certain basic principles of radiation beam dosage is often underestimated. Since any failure of understanding may seriously impair the efficiency of the team treating the patient, the discussion of these problems (and especially the monitoring of the results of such discussion by means of oral and written tests) deserves a high priority. Contrary to traditional practice, there would seem to be no good reason why teaching of radiation beam dosage, and the effect on dose-rate of changes in the treatment distance or in the amount of scattered radiation, should not begin in the very first week of training and be immediately integrated with discussion of the dose-rate information available at every radiotherapy unit when the patient is treated. A preliminary course of physics lectures does not usually make the understanding of these principles any easier and can be done either concurrently or later. For many radiotherapy trainees and for many doctors in other fields, comparison with drug dosage and with the brightness and scatter of ordinary light beams, avoiding technical terms so far as possible, may achieve a better initial understanding of basic principles than is achieved by mathematical equations and theoretical physics. (author)

When and how should we teach the basic concepts of radiation beam dosage

Energy Technology Data Exchange (ETDEWEB)

Brewin, T B [Institute of Radiotherapeutics and Oncology, Glasgow (UK)

1977-06-01

The difficulty that many trainees, including those medically qualified, have in achieving a sound working grasp of certain basic principles of radiation beam dosage is often underestimated. Since any failure of understanding may seriously impair the efficiency of the team treating the patient, the discussion of these problems (and especially the monitoring of the results of such discussion by means of oral and written tests) deserves a high priority. Contrary to traditional practice, there would seem to be no good reason why teaching of radiation beam dosage, and the effect on dose-rate of changes in the treatment distance or in the amount of scattered radiation, should not begin in the very first week of training and be immediately integrated with discussion of the dose-rate information available at every radiotherapy unit when the patient is treated. A preliminary course of physics lectures does not usually make the understanding of these principles any easier and can be done either concurrently or later. For many radiotherapy trainees and for many doctors in other fields, comparison with drug dosage and with the brightness and scatter of ordinary light beams, avoiding technical terms so far as possible, may achieve a better initial understanding of basic principles than is achieved by mathematical equations and theoretical physics.

Uniform irradiation using rotational-linear scanning method for narrow synchrotron radiation beam

International Nuclear Information System (INIS)

Nariyama, N.; Ohnishi, S.; Odano, N.

2004-01-01

At SPring-8, photon intensity monitors for synchrotron radiation have been developed. Using these monitors, the responses of radiation detectors and dosimeters to monoenergetic photons can be measured. In most cases, uniform irradiation to the sample is necessary. Here, two scanning methods are proposed. One is an XZ-linear scanning method, which moves the sample simultaneously in both the X and Z direction, that is, in zigzag fashion. The other is a rotational-linear scanning method, which rotates the sample moving in the X direction. To investigate the validity of the two methods, thermoluminescent dosimeters were irradiated with a broad synchrotron-radiation beam, and the readings from the two methods were compared with that of the dosimeters fixed in the beam. The results for both scanning methods virtually agreed with that of the fixed method. The advantages of the rotational-linear scanning method are that low- and medium-dose irradiation is possible, uniformity is excellent and the load to the scanning equipment is light: hence, this method is superior to the XZ-linear scanning method for most applications. (author)

Nicaraven attenuates radiation-induced injury in hematopoietic stem/progenitor cells in mice.

Directory of Open Access Journals (Sweden)

Miho Kawakatsu

Full Text Available Nicaraven, a chemically synthesized hydroxyl radical-specific scavenger, has been demonstrated to protect against ischemia-reperfusion injury in various organs. We investigated whether nicaraven can attenuate radiation-induced injury in hematopoietic stem/progenitor cells, which is the conmen complication of radiotherapy and one of the major causes of death in sub-acute phase after accidental exposure to high dose radiation. C57BL/6 mice were exposed to 1 Gy γ-ray radiation daily for 5 days in succession (a total of 5 Gy, and given nicaraven or a placebo after each exposure. The mice were sacrificed 2 days after the last radiation treatment, and the protective effects and relevant mechanisms of nicaraven in hematopoietic stem/progenitor cells with radiation-induced damage were investigated by ex vivo examination. We found that post-radiation administration of nicaraven significantly increased the number, improved the colony-forming capacity, and decreased the DNA damage of hematopoietic stem/progenitor cells. The urinary levels of 8-oxo-2'-deoxyguanosine, a marker of DNA oxidation, were significantly lower in mice that were given nicaraven compared with those that received a placebo treatment, although the levels of intracellular and mitochondrial reactive oxygen species in the bone marrow cells did not differ significantly between the two groups. Interestingly, compared with the placebo treatment, the administration of nicaraven significantly decreased the levels of the inflammatory cytokines IL-6 and TNF-α in the plasma of mice. Our data suggest that nicaraven effectively diminished the effects of radiation-induced injury in hematopoietic stem/progenitor cells, which is likely associated with the anti-oxidative and anti-inflammatory properties of this compound.

Short vegetal-fiber reinforced HDPE—A study of electron-beam radiation treatment effects on mechanical and morphological properties

International Nuclear Information System (INIS)

Ferreira, Maiara S.; Sartori, Mariana N.; Oliveira, Rene R.; Guven, Olgun; Moura, Esperidiana A.B.

2014-01-01

Graphical abstract: - Highlights: • HDPE reinforced with short piassava fiber composites were prepared by melt-mixing processing. • Glycidyl methacrylate (GMA) was tested as a radiation cross-linking agent. • The materials were irradiated with 100 and 200 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. • The better interfacial adhesion between fiber and HDPE matrix was observed for composites with GMA addition irradiated with radiation dose of 200 kGy. - Abstract: The effects of electron-beam radiation treatment on fiber-matrix adhesion and mechanical properties of short piassava fibers reinforced high density polyethylene (HDPE) matrix were studied. Glycidyl methacrylate (GMA) was added at 2.5% and 5.0% (on piassava fiber wt) as a cross-linking agent and the effects upon the properties of the resulting composites treated by electron-beam radiation were also examined. HDPE reinforced with short piassava fiber composites was prepared by melt-mixing processing, using a twin screw extruder machine. The materials were irradiated with 100 and 200 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. Material samples were submitted to mechanical and thermo-mechanical tests and SEM analyses. Correlation between properties was discussed. The comparison of mechanical and thermo-mechanical properties of the composites showed that electron-beam radiation treatment produced a significant improvement in mechanical properties, when compared with the non-irradiated composite sample and neat HDPE. Scanning electron microscopy (SEM) studies of the composite failure surfaces indicated that there was an improved adhesion between fiber and matrix. Examination of the failure surfaces indicated dependence of the interfacial adhesion upon the radiation dose and GMA content. Better interfacial adhesion between fiber and HDPE matrix was observed for composites with 5.0% GMA addition and treated with electron-beam

Short vegetal-fiber reinforced HDPE—A study of electron-beam radiation treatment effects on mechanical and morphological properties

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Maiara S.; Sartori, Mariana N.; Oliveira, Rene R. [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, zip code 05508-000 São Paulo, SP (Brazil); Guven, Olgun [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, Beytepe, zip code 06800 Ankara (Turkey); Moura, Esperidiana A.B., E-mail: eabmoura@ipen.br [Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, zip code 05508-000 São Paulo, SP (Brazil)

2014-08-15

Graphical abstract: - Highlights: • HDPE reinforced with short piassava fiber composites were prepared by melt-mixing processing. • Glycidyl methacrylate (GMA) was tested as a radiation cross-linking agent. • The materials were irradiated with 100 and 200 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. • The better interfacial adhesion between fiber and HDPE matrix was observed for composites with GMA addition irradiated with radiation dose of 200 kGy. - Abstract: The effects of electron-beam radiation treatment on fiber-matrix adhesion and mechanical properties of short piassava fibers reinforced high density polyethylene (HDPE) matrix were studied. Glycidyl methacrylate (GMA) was added at 2.5% and 5.0% (on piassava fiber wt) as a cross-linking agent and the effects upon the properties of the resulting composites treated by electron-beam radiation were also examined. HDPE reinforced with short piassava fiber composites was prepared by melt-mixing processing, using a twin screw extruder machine. The materials were irradiated with 100 and 200 kGy using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. Material samples were submitted to mechanical and thermo-mechanical tests and SEM analyses. Correlation between properties was discussed. The comparison of mechanical and thermo-mechanical properties of the composites showed that electron-beam radiation treatment produced a significant improvement in mechanical properties, when compared with the non-irradiated composite sample and neat HDPE. Scanning electron microscopy (SEM) studies of the composite failure surfaces indicated that there was an improved adhesion between fiber and matrix. Examination of the failure surfaces indicated dependence of the interfacial adhesion upon the radiation dose and GMA content. Better interfacial adhesion between fiber and HDPE matrix was observed for composites with 5.0% GMA addition and treated with electron-beam

Installation And Test Of Electron Beam Generation System To Produce Far-Infrared Radiation And X-Ray Pulses

International Nuclear Information System (INIS)

Wichaisirimongkol, Pathom; Jinamoon, Witoon; Khangrang, Nopadon; Kusoljariyakul, Keerati; Rhodes, Michael W.; Rimjaem, Sakhorn; Saisut, Jatuporn; Chitrlada, Thongbai; Vilaithong, Thiraphat; Wiedemann, Helmut

2005-10-01

SURIYA project at the Fast Neutron Research Facility, Chiang Mai University, aims to establish a facility to generate femtosecond electron beams. This electron beam can be used to generate high intensity far-infrared radiation and ultra-short X-ray pulses. The main components of the system are a 3 MeV RF electron gun with a thermionic cathode, an a-magnet as a bunch compressor, and post acceleration 15-20 MeV by a linear accelerator (linac). Between the main components, there are focusing quadrupole magnets and steering magnets to maintain the electron beam within a high vacuum tube. At the end of the beam transport line, a dipole magnet has been installed to function as a beam dump and an energy spectrometer. After the installation and testing of individual major components were completed, we have been investigating the generation of the electron beam, intense far- infrared radiation and ultra short X-ray pulses

Development of a synchrotron radiation beam monitor for the Integrable Optics Test Accelerator

Energy Technology Data Exchange (ETDEWEB)

Scarpelli, Andrea [Univ. of Ferrara (Italy)

2016-01-01

Nonlinear integrable optics applied to beam dynamics may mitigate multi-particle instabilities, but proof of principle experiments have never been carried out. The Integrable Optics Test Accelerator (IOTA) is an electron and proton storage ring currently being built at Fermilab, which addresses tests of nonlinear lattice elements in a real machine in addition to experiments on optical stochastic cooling and on the single-electron wave function. These experiments require an outstanding control over the lattice parameters, achievable with fast and precise beam monitoring systems. This work describes the steps for designing and building a beam monitor for IOTA based on synchrotron radiation, able to measure intensity, position and transverse cross-section beam.

Use of spectra from foil-excited heavy-ion beams to interpret radiation from plasmas

International Nuclear Information System (INIS)

Johnson, B.M.

1978-01-01

Spectra from foil-excited heavy ion beams can be used to investigate the relative abundance and charge state composition of heavy metal contaminants which cause severe radiative energy losses in tokamak-produced plasmas. The degree of ionization of these metals in the tokamak plasma is not well known because of uncertainties in ionization and recombination rates and particle confinement times. Only a few stages of ionization are typically prominent in foil-excited spectra, however, and both the most probable charge state and distribution width are well known. Highly ionized heavy ions (e.g., Ti, Mo, W and Au) which span the range of charge states found in present tokamaks were produced by passing beams from the Brookhaven MP tandem Van de Graaff accelerator facility through 20 μg/cm 2 carbon stripping foils. EUV radiation was recorded with a grazing incidence spectrometer. Comparisons of the beam-foil spectra with radiation from plasmas, and recent direct determinations of atomic oscillator strengths for principal resonance lines of such highly ionized species as Li-like iron (Fe 23+ ), Na-like bromine (Br 24+ ), and Cu-like iodine (I 24+ ) are discussed

Radiochromic film for dosimetric measurements in radiation shielding composites synthesized for applied in radiology procedures of high dose

Energy Technology Data Exchange (ETDEWEB)

Fontainha, C. C. P. [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Baptista N, A. T.; Faria, L. O., E-mail: crissia@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

2015-10-15

Full text: Medical radiology offers great benefit to patients. However, although specifics procedures of high dose, as fluoroscopy, Interventional Radiology, Computed Tomography (CT) make up a small percent of the imaging procedures, they contribute to significantly increase dose to population. The patients may suffer tissue damage. The probability of deterministic effects incidence depends on the type of procedure performed, exposure time, and the amount of applied dose at the irradiated area. Calibrated radiochromic films can identify size and distribution of the radiated fields and measure intensities of doses. Radiochromic films are sensitive for doses ranging from 0.1 to 20 c Gy and they have the same response for X-rays effective energies ranging from 20 to 100 keV. New radiation attenuators materials have been widely investigated resulting in dose reduction entrance skin dose. In this work, Bi{sub 2}O{sub 3} and ZrO{sub 2}:8 % Y{sub 2}O{sub 3} composites were obtained by mixing them with P(VDF-Tr Fe) copolymers matrix from casting method and then characterized by Ftir. Dosimetric measurements were obtained with Xr-Q A2 Gafchromic radiochromic films. In this setup, one radiochromic film is directly exposed to the X-rays beam and another one measures the attenuated beam were exposed to an absorbed dose of 10 mGy of RQR5 beam quality (70 kV X-ray beam). Under the same conditions, irradiated Xr-Q A2 films were stored and scanned measurement in order to obtain a more reliable result. The attenuation factors, evaluated by Xr-Q A2 radiochromic films, indicate that both composites are good candidates for use as patient radiation shielding in high dose medical procedures. (Author)

Sensor device for X-ray beam to evaluate the radiation focal spot

International Nuclear Information System (INIS)

Santos, Lara H.E. dos; Schiabel, Homero; Silva, Aderbal A.B. da; Marques, Paulo M.A.; Campos, Marcelo; Slaets, Annie F.F.

1996-01-01

A new electronic device to determine the position of the central ray of the radiation beam is proposed. The device aims to provide a perfect alignment of test objects used for evaluating focal spots with this reference axis

Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

International Nuclear Information System (INIS)

Paulson, Eric S.; Erickson, Beth; Schultz, Chris; Allen Li, X.

2015-01-01

Purpose: The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP. Methods: A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI-optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off-resonance and gradient nonlinearity-induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams. Results: The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast-to-noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off-resonance and gradient nonlinearity induced geometric distortions. Conclusions: The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In

Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

Energy Technology Data Exchange (ETDEWEB)

Paulson, Eric S., E-mail: epaulson@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Erickson, Beth; Schultz, Chris; Allen Li, X. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States)

2015-01-15

Purpose: The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP. Methods: A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI-optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off-resonance and gradient nonlinearity-induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams. Results: The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast-to-noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off-resonance and gradient nonlinearity induced geometric distortions. Conclusions: The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In

Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

Science.gov (United States)

Jeong, Ye-Ji; Jung, Myung Gu; Son, Yeonghoon; Jang, Jun-Ho; Lee, Yoon-Jin; Kim, Sung-Ho; Ko, Young-Gyo; Lee, Yun-Sil; Lee, Hae-June

2015-01-01

Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

Determination of the effective energy in X-rays standard beams, mammography level

Energy Technology Data Exchange (ETDEWEB)

Correa, Eduardo de Lima; Vivolo, Vitor; Potiens, Maria da Penha A., E-mail: Vivolo@ipen.b, E-mail: mppalbu@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The X-rays beams used in diagnostic radiology are heterogeneous. This means that, in a radiological beam, it can be found photons with different energies. Because of that is common to work with the concept of effective energy. In this study the effective energy of an X-rays system used in instruments calibration was determined, as part of the mammography radiation qualities establishment. The procedure presented here was developed based on information found in the literature. The X-ray mass attenuation coefficients for aluminum, given by NIST web site, were used and the mathematical adjusts were done using the Origin 8.0 program. The results are part of the mammographic X-rays beams characteristics determination and it is important to keep the quality of this reference system. (author)

Monochromaticity of optical radiation of Smith-Purcell generated by electron beam with 75 keV energy

International Nuclear Information System (INIS)

Adishchev, Yu.N.; Vukolov, A.V.; Karlovets, D.V.; Potylitsyn, A.P.; Kube, G.

2005-01-01

The monochromatism of the Smith-Purcell optical radiation generated by a 75-keV electron beam with a final emittance of ε = 0.65 x 10 -4 mm rad that passes over an optical grating with a period of D = 0.833 μm has been analyzed. It has been shown that the monochromatism (line width) of the Smith-Purcell radiation is determined not only by the angular aperture of a monochromator but also by the divergence of the electron beam [ru

Estimating the effective radiation dose imparted to patients by intraoperative cone-beam computed tomography in thoracolumbar spinal surgery.

Science.gov (United States)

Lange, Jeffrey; Karellas, Andrew; Street, John; Eck, Jason C; Lapinsky, Anthony; Connolly, Patrick J; Dipaola, Christian P

2013-03-01

Observational. To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases

Beam line design using G4BeamLine

CERN Document Server

Dogan, Arda

2014-01-01

In Turkey in Ankara TAEK SANAEM Proton Accelerator Facility (PAF), there is a cyclotron which produces a focused intense 30 MeV proton beam and sends this beam to four different arms, three of which uses this beam to produce pharmaceutical medicine. The remaining one is spared for R&D purposes and the idea was to use these protons coming out from the fourth arm to use space radiation tests, which cannot be done in Turkey at the moment. However, according to SCC 25100 standards which is for 30 MeV protons, the beam coming out of cyclotron is too intense and focused to use for space radiation tests. Therefore, the main aim of my project is to design a beam line which will defocus the beam and reduce the flux so that the space radiation tests can be done according to the standards of SCC 25100.

Radiation-Induced Graft Polymerization: Gamma Radiation and Electron Beam Technology for Materials Development

International Nuclear Information System (INIS)

Madrid, Jordan F.; Cabalar, Patrick Jay; Lopez, Girlie Eunice; Abad, Lucille V.

2015-01-01

The formation of functional hybrid materials by attaching polymer chains with advantageous tailored properties to the surface of a base polymer with desirable bulk character is an attractive application of graft copolymerization. Radiation-induced graft polymerization (RIGP) has been a popular approach for surface modification of polymers because of its merits over conventional chemical processes. RIGP, which proceeds primarily via free radical polymerization process, has the advantages such as simplicity, low cost, control over process and adjustment of the materials composition and structure. RIGP can be performed using either electron beam or gamma radiation and it can be applied to both synthetic and natural polymers. These merits make RIGP a popular research topic worldwide. Moreover, the materials synthesized and produced via RIGP has found applications, and were proposed to produce continuous impact, in the fields of medicine, agriculture, pollution remediation, rare earth and valuable metals recovery, fuel cell membrane synthesis and catalysis to name a few. From 2012 our group has performed electron beam and gamma radiation-induced graft polymerization of various monomers onto polymers of natural and synthetic origins (e.g. monomers - glycidyl methacrylate, styrene, acrylonitrile, N,N-dimethylaminoethyl methacrylate; base polymers – polyethylene/polypropylene nonwoven fabric, polypropylene nonwoven fabric pineapple fibers, cellulose nonwoven fabric microcrystalline cellulose). We tested these grafted materials for heavy metals (Pb, Ni, Cu) and organic molecule removal from aqueous solutions and E. coli activity (using reversible addition fragmentation chain transfer RAFT mediated grafting). The results clearly showed the success of materials modified via FIGP in these applications. Currently, we are studying the applications of grafted materials on treatment of waste waters from tanning industry, value addition to abaca nonwoven fabrics cell sheet

Ion beam induced charge and cathodoluminescence imaging of response uniformity of CVD diamond radiation detectors

CERN Document Server

Sellin, P J; Galbiati, A; Maghrabi, M; Townsend, P D

2002-01-01

The uniformity of response of CVD diamond radiation detectors produced from high quality diamond film, with crystallite dimensions of >100 mu m, has been studied using ion beam induced charge imaging. A micron-resolution scanning alpha particle beam was used to produce maps of pulse height response across the device. The detectors were fabricated with a single-sided coplanar electrode geometry to maximise their sensitivity to the surface region of the diamond film where the diamond crystallites are highly ordered. High resolution ion beam induced charge images of single crystallites were acquired that demonstrate variations in intra-crystallite charge transport and the termination of charge transport at the crystallite boundaries. Cathodoluminescence imaging of the same crystallites shows an inverse correlation between the density of radiative centres and regions of good charge transport.

SU-F-T-174: Patient-Specific Point Dose Measurement Using Fiber Optic Radiation Sensor Using Cerenkov Radiation for Proton Therapeutic Beam

Energy Technology Data Exchange (ETDEWEB)

Son, J [Korea University, Seoul, Seoul (Korea, Republic of); National Cancer Center, Goyang-si (Korea, Republic of); Kim, M [Dongnam Institute of Radiological & Medical Sciences, Busan, Busan (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of); Shin, D [National Cancer Center, Goyang-si (Korea, Republic of)

2016-06-15

Purpose: A fiber-optic radiation sensor using Cerenkov radiation (FOCR) has been widely studied for use as a dosimeter for proton therapeutic beam. We developed the FOCR, and it applied to patient-specific point dose measurement in order to evaluate the effectiveness of the FOCR system for proton therapy QA. Methods: Calibration of FOCR was performed with an ionization chamber whose absolute doses were determined according to the IAEA TRS-398 protocol. To determine the calibration curve, the FOCR was irradiated perpendicularly to the proton beam at the 13 dose levels steps. We selected five actual patient treatment plans performed at proton therapy center and compared the resulting FOCR measurements with the ionization chamber measurements. Results: The Cerenkov light yield of the FOCR increases linearly with as the dose measured using the ionization chamber increases from 0 cGy to 500 cGy. The results indicate that the fitting curve is linear, suggesting that dose measurement based on the light yield of the FOCR is possible. The results of proton radiation dose QA performed using the FOCR for 10 proton fields and five patients are good agreement with an ionization chamber. Conclusion: We carried out the patient QA using the FOCR for proton therapeutic beam and evaluated the effectiveness of the FOCR as a proton therapy QA tool. Our results indicate that the FOCR is suitable for use in patient QA of clinical proton beams.

Radiation Safety System for SPIDER Neutral Beam Accelerator

International Nuclear Information System (INIS)

Sandri, S.; Poggi, C.; Coniglio, A.; D'Arienzo, M.

2011-01-01

SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

Whole acute toxicity removal from industrial and domestic effluents treated by electron beam radiation: emphasis on anionic surfactants

International Nuclear Information System (INIS)

Moraes, M.C.F.; Romanelli, M.F; Sena, H.C.; Pasqualini da Silva, G.; Sampa, M.H.O.; Borrely, S.I.

2004-01-01

Electron beam radiation has been applied to improve real industrial and domestic effluents received by Suzano wastewater treatment plant. Radiation efficacy has been evaluated as toxicity reduction, using two biological assays. Three sites were sampled and submitted for toxicity assays, anionic surfactant determination and electron beam irradiation. This paper shows the reduction of acute toxicity for both test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. The raw toxic effluents exibitted from 0.6 ppm up to 11.67 ppm for anionic surfactant before being treated by the electron beam. Radiation processing resulted in reduction of the acute toxicity as well as surfactant removal. The final biological effluent was in general less toxic than other sites but the presence of anionic surfactants was evidenced

Whole acute toxicity removal from industrial and domestic effluents treated by electron beam radiation: emphasis on anionic surfactants

Energy Technology Data Exchange (ETDEWEB)

Moraes, M.C.F. E-mail: mariacristinafm@uol.com.br; Romanelli, M.F; Sena, H.C.; Pasqualini da Silva, G.; Sampa, M.H.O.; Borrely, S.I

2004-10-01

Electron beam radiation has been applied to improve real industrial and domestic effluents received by Suzano wastewater treatment plant. Radiation efficacy has been evaluated as toxicity reduction, using two biological assays. Three sites were sampled and submitted for toxicity assays, anionic surfactant determination and electron beam irradiation. This paper shows the reduction of acute toxicity for both test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. The raw toxic effluents exibitted from 0.6 ppm up to 11.67 ppm for anionic surfactant before being treated by the electron beam. Radiation processing resulted in reduction of the acute toxicity as well as surfactant removal. The final biological effluent was in general less toxic than other sites but the presence of anionic surfactants was evidenced.

Microdosimetry of 0.5 to 2.0 MeV electron beams

International Nuclear Information System (INIS)

Braby, L.A.; Roesch, W.C.

1980-08-01

The energy imparted in microscopic volumes by electron beams with initial energies from 0.5 to 2.0 MeV has been measured at various depths in plastic. The problems associated with measuring energy deposition spectra of low LET radiations are serious, but the potential importance of these measurements in radiation biophysics justifies the effort required to obtain them. Recent results obtained by Goodhead et al. indicate an RBE greater than 2 for 0.3 keV x-rays compared to 250 kV x-rays, and our results with Chlamydomonas reinhardi indicate an RBE of 1.6 for a 1.5 MeV electron beam at a depth of 400 gm/cm 2 in lucite compared to the same beam at the surface. Development of a theory which appears to explain these results in terms of the microscopic distribution of energy deposition has motivated a detailed study of energy deposition spectra for an electron beam attenuated by various thicknesses of lucite. Simulated sites from 0.5 to 1.9 μm in diameter were studied. The values of anti y determined in these single event measurements compare favorably with those calculated from direct measurements of z reported previously. As expected, the means of the distributions increase significantly with increasing depth in an absorber

Measurement and analysis. Ultrasonic testing. Study of the attenuation of ultrasonic beams through steels

International Nuclear Information System (INIS)

Canella, G.

1977-01-01

Anisotropy, inclusions, segregations and grain size are factors affecting the mechanical properties of steel and determining, at the same time, attenuation of an untrasonic beam crossing it. A system was developed, which offers guarantees of good reproducibility (within 5%) obtained with a device applying a constant and uniform pressure on the probe and using oil with very low viscosity and surface tension as couplant liquid. This oil, generally used as penetrant, is excellent by the rapidity of its constant response and by the thin layer formed which is free from air bubbles between probe and piece. Measurements of reflection loss were also carried out and investigated about the influence on such loss of: couplant liquid; type of transducer; type of piezoelectric protection. For transducers whose surface is protected by an hard coat loss by reflection (about 1 dB) varies within the measuring error, for the different couplant liquids. For transducers with unprotected sensitive surface, loss depends on the type of crystal and is significantly reduced (from 3 dB to 0,5 dB approximately) with an appropriate rubber layer. In both cases; loss proved to be independent of frequency. The samples were subjected to different heat treatments and, for each measurement of amplitude and frequency attenuation and structure micrographies were carried out. These methods of inspections can be applied in industry without any great difficulty

Thermal radiation heat transfer in participating media by finite volume discretization using collimated beam incidence

Science.gov (United States)

Harijishnu, R.; Jayakumar, J. S.

2017-09-01

The main objective of this paper is to study the heat transfer rate of thermal radiation in participating media. For that, a generated collimated beam has been passed through a two dimensional slab model of flint glass with a refractive index 2. Both Polar and azimuthal angle have been varied to generate such a beam. The Temperature of the slab and Snells law has been validated by Radiation Transfer Equation (RTE) in OpenFOAM (Open Field Operation and Manipulation), a CFD software which is the major computational tool used in Industry and research applications where the source code is modified in which radiation heat transfer equation is added to the case and different radiation heat transfer models are utilized. This work concentrates on the numerical strategies involving both transparent and participating media. Since Radiation Transfer Equation (RTE) is difficult to solve, the purpose of this paper is to use existing solver buoyantSimlpeFoam to solve radiation model in the participating media by compiling the source code to obtain the heat transfer rate inside the slab by varying the Intensity of radiation. The Finite Volume Method (FVM) is applied to solve the Radiation Transfer Equation (RTE) governing the above said physical phenomena.

Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution. [aerosol pollution monitoring

Science.gov (United States)

Fymat, A. L.

1976-01-01

The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.

Dual-energy (MV/kV) CT with probabilistic attenuation mapping for IGRT applications

Science.gov (United States)

Pearson, Erik; Pan, Xiaochuan; Pelizzari, Charles

2015-03-01

Imaging plays an important role in the delivery of external beam radiation therapy. It is used to confirm the setup of the patient and to ensure accurate targeting and delivery of the therapeutic radiation dose. Most modern linear accelerators come equipped with a flat panel detector opposite the MV source as well as an independent kV imaging system, typically mounted perpendicular to the MV beam. kV imaging provides superior soft tissue contrast and is typically lower dose to the patient than MV imaging, however it can suffer from artifacts caused by metallic objects such as implants and immobilization devices. In addition to being less artifact prone, MV imaging also provides a direct measure of the attenuation for the MV beam which is useful for computing the therapeutic dose distributions. Furthermore either system requires a large angular coverage, which is slow for large linear accelerators. We present a method for reconstructing tomographic images from data acquired at multiple x-ray beam energies using a statistical model of inherent physical properties of the imaged object. This approach can produce image quality superior to traditional techniques in the case of limited measurement data (angular sampling range, sampling density or truncated projections) and/or conditions in which the lower energy image would typically suffer from corrupting artifacts such as the presence of metals in the object. Both simulation and real data results are shown.

X-ray diffraction using synchrotron radiation on the G.I.L.D.A. beam line at the E.S.R.F

Energy Technology Data Exchange (ETDEWEB)

Balerna, A [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Meneghini, C [INFN, Laboratori Nazionali di Frascati, Rome (Italy); [INFM, Genoa (Italy); Bordoni, S [Rome Univ. ` Tor Vergata` (Italy). Dip. di Fisica; Mobilio, S [Rome Univ. III (Italy). Dip. di Fisica ` E. Amaldi`

1996-09-01

The aim of this lecture is to make a short introduction on Synchrotron radiation, its history and main properties. The main components of a synchrotron radiation beam line will be described. The Italian beam line, General purpose Italian beam line Line for Diffraction and Absorption (G.I.L.D.A.) at the European Synchrotron Radiation Facility (E.S.R.F.) in Grenoble will be used as an example. The G.I.L.D.A. diffractometer will be described in detail reporting also some experimental results.

Improving intensity-modulated radiation therapy using the anatomic beam orientation optimization algorithm

International Nuclear Information System (INIS)

Potrebko, Peter S.; McCurdy, Boyd M. C.; Butler, James B.; El-Gubtan, Adel S.

2008-01-01

A novel, anatomic beam orientation optimization (A-BOO) algorithm is proposed to significantly improve conventional intensity-modulated radiation therapy (IMRT). The A-BOO algorithm vectorially analyses polygonal surface mesh data of contoured patient anatomy. Five optimal (5-opt) deliverable beam orientations are selected based on (1) tangential orientation bisecting the target and adjacent organ's-at-risk (OARs) to produce precipitous dose gradients between them and (2) parallel incidence with polygon features of the target volume to facilitate conformal coverage. The 5-opt plans were compared to standard five, seven, and nine equiangular-spaced beam plans (5-equi, 7-equi, 9-equi) for: (1) gastric, (2) Radiation Therapy Oncology Group (RTOG) P-0126 prostate, and (3) RTOG H-0022 oropharyngeal (stage-III, IV) cancer patients. In the gastric case, the noncoplanar 5-opt plan reduced the right kidney V 20 Gy by 32.2%, 23.2%, and 20.6% compared to plans with five, seven, and nine equiangular-spaced beams. In the prostate case, the coplanar 5-opt plan produced similar rectal sparing as the 7-equi and 9-equi plans with a reduction of the V 75, V 70, V 65, and V 60 Gy of 2.4%, 5.3%, 7.0%, and 9.5% compared to the 5-equi plan. In the stage-III and IV oropharyngeal cases, the noncoplanar 5-opt plan substantially reduced the V 30 Gy and mean dose to the contralateral parotid compared to plans with five, seven, and nine equiangular-spaced beams: (stage-III) 7.1%, 5.2%, 6.8%, and 5.1, 3.5, 3.7 Gy and (stage-IV) 10.2%, 10.2%, 9.8% and 7.0, 7.1, 7.2 Gy. The geometry-based A-BOO algorithm has been demonstrated to be robust for application to a variety of IMRT treatment sites. Beam orientations producing significant improvements in OAR sparing over conventional IMRT can be automatically produced in minutes compared to hours with existing dose-based beam orientation optimization methods

Two-parametric model of electron beam in computational dosimetry for radiation processing

International Nuclear Information System (INIS)

Lazurik, V.M.; Lazurik, V.T.; Popov, G.; Zimek, Z.

2016-01-01

Computer simulation of irradiation process of various materials with electron beam (EB) can be applied to correct and control the performances of radiation processing installations. Electron beam energy measurements methods are described in the international standards. The obtained results of measurements can be extended by implementation computational dosimetry. Authors have developed the computational method for determination of EB energy on the base of two-parametric fitting of semi-empirical model for the depth dose distribution initiated by mono-energetic electron beam. The analysis of number experiments show that described method can effectively consider random displacements arising from the use of aluminum wedge with a continuous strip of dosimetric film and minimize the magnitude uncertainty value of the electron energy evaluation, calculated from the experimental data. Two-parametric fitting method is proposed for determination of the electron beam model parameters. These model parameters are as follow: E 0 – energy mono-energetic and mono-directional electron source, X 0 – the thickness of the aluminum layer, located in front of irradiated object. That allows obtain baseline data related to the characteristic of the electron beam, which can be later on applied for computer modeling of the irradiation process. Model parameters which are defined in the international standards (like E p – the most probably energy and R p – practical range) can be linked with characteristics of two-parametric model (E 0 , X 0 ), which allows to simulate the electron irradiation process. The obtained data from semi-empirical model were checked together with the set of experimental results. The proposed two-parametric model for electron beam energy evaluation and estimation of accuracy for computational dosimetry methods on the base of developed model are discussed. - Highlights: • Experimental and computational methods of electron energy evaluation. • Development

Ambient ultraviolet radiation induces protective responses in soybean but does not attenuate indirect defense

International Nuclear Information System (INIS)

Winter, Thorsten R.; Rostas, Michael

2008-01-01

We investigated the effects of ambient ultraviolet (UV) radiation on (i) the performance and chemistry of soybean plants, (ii) the performance of Spodoptera frugiperda and (iii) the foraging behavior of the herbivore's natural enemy Cotesia marginiventris which exploits herbivore-induced plant volatiles (VOC) for host location. The accumulation of protective phenolics was faster in plants receiving ambient UV than in controls exposed to sun light lacking UV. Accordingly, isorhamnetin- and quercetin-based flavonoids were increased in UV exposed plants. No UV effects were found on the performance and feeding behavior of S. frugiperda. Herbivore-damaged plants emitted the same VOC when grown under ambient or attenuated UV for 5, 10 or 30 days. Consequently, C. marginiventris was attracted but did not discriminate between exposed and unexposed soybeans. In summary, ambient UV radiation affected soybean morphology and physiology but did not destabilize interactions between trophic levels. - Ambient ultraviolet radiation does not alter induced VOC emission in soybean and thus host location of the parasitoid Cotesia marginiventris remains effective

Determination of the LEP Beam Energy using Radiative Fermion-pair Events, 2004

CERN Document Server

Abbiendi, G; Åkesson, P F; Alexander, G; Allison, J; Amaral, P; Anagnostou, G; Anderson, K J; Asai, S; Axen, D A; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, Franco Luigi; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, R J; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, Dean A; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Masetti, G; Mashimo, T; Mättig, P; McKenna, J A; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

2004-01-01

We present a determination of the LEP beam energy using "radiative return" fermion-pair events recorded at centre-of-mass energies from 183 GeV to 209 GeV. We find no evidence of a disagreement between the OPAL data and the LEP Energy Workings Group's standard calibration. Including the energy- averaged 11 MeV uncertainty in the standard determination, the beam energy we obtain from the OPAL data is higher than that obtained from the LEP calibration by 0+-34(stat.)+-27(syst.)MeV

The potential of proton beam radiation therapy in lung cancer (including mesothelioma)

Energy Technology Data Exchange (ETDEWEB)

Bjelkengren, Goeran [Univ. Hospital, Malmoe (Sweden). Dept. of Oncology; Glimelius, Bengt [Karolinska Inst., Stockholm (Sweden). Dept. of Oncology and Pathology; Akademiska sjukhuset, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology

2005-12-01

A Swedish group of oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. It is estimated that about 350 patients with lung cancer and about 20 patients with mesothelioma annually may benefit from proton beam therapy.

A self-adaptive metamaterial beam with digitally controlled resonators for subwavelength broadband flexural wave attenuation

Science.gov (United States)

Li, Xiaopeng; Chen, Yangyang; Hu, Gengkai; Huang, Guoliang

2018-04-01

Designing lightweight materials and/or structures for broadband low-frequency noise/vibration mitigation is an issue of fundamental importance both practically and theoretically. In this paper, by leveraging the concept of frequency-dependent effective stiffness control, we numerically and experimentally demonstrate, for the first time, a self-adaptive metamaterial beam with digital circuit controlled mechanical resonators for strong and broadband flexural wave attenuation at subwavelength scales. The digital controllers that are capable of feedback control of piezoelectric shunts are integrated into mechanical resonators in the metamaterial, and the transfer function is semi-analytically determined to realize an effective bending stiffness in a quadratic function of the wave frequency for adaptive band gaps. The digital as well as analog control circuits as the backbone of the system are experimentally realized with the guarantee stability of the whole electromechanical system in whole frequency regions, which is the most challenging problem so far. Our experimental results are in good agreement with numerical predictions and demonstrate the strong wave attenuation in almost a three times larger frequency region over the bandwidth of a passive metamaterial. The proposed metamaterial could be applied in a range of applications in the design of elastic wave control devices.

An implantable radiation dosimeter for use in external beam radiation therapy

International Nuclear Information System (INIS)

Scarantino, Charles W.; Ruslander, David M.; Rini, Christopher J.; Mann, Gregory G.; Nagle, H. Troy; Black, Robert D.

2004-01-01

An implantable radiation dosimeter for use with external beam therapy has been developed and tested both in vitro and in canines. The device uses a MOSFET dosimeter and is polled telemetrically every day during the course of therapy. The device is designed for permanent implantation and also acts as a radiographic fiducial marker. Ten dogs (companion animals) that presented with spontaneous, malignant tumors were enrolled in the study and received an implant in the tumor CTV. Three dogs received an additional implant in collateral normal tissue. Radiation therapy plans were created for the animals and they were treated with roughly 300 cGy daily fractions until completion of the prescribed cumulative dose. The primary endpoints of the study were to record any adverse events due to sensor placement and to monitor any movement away from the point of placement. No adverse events were recorded. Unacceptable device migration was experienced in two subjects and a retention mechanism was developed to prevent movement in the future. Daily dose readings were successfully acquired in all subjects. A rigorous in vitro calibration methodology has been developed to ensure that the implanted devices maintain an accuracy of ±3.5% relative to an ionization chamber standard. The authors believe that an implantable radiation dosimeter is a practical and powerful tool that fosters individualized patient QA on a daily basis

Recoil separators for radiative capture using radioactive ion beams. Recent advances and detection techniques

Energy Technology Data Exchange (ETDEWEB)

Ruiz, Chris [TRIUMF, Vancouver, BC (Canada); Greife, Uwe; Hager, Ulrike [Colorado School of Mines, Golden, CO (United States)

2014-06-15

Radiative capture reactions involving the fusion of hydrogen or helium are ubiquitous in the stellar history of the universe, and are some of the most important reactions in the processes that govern nucleosynthesis and energy generation in both static and explosive scenarios. However, radiative capture reactions pose some of the most difficult experimental challenges due to extremely small cross sections. With the advent of recoil separators and techniques in inverse kinematics, it is now possible to measure radiative capture reactions on very short-lived radioactive nuclei, and in the presence of high experimental backgrounds. In this paper we review the experimental needs for making measurements of astrophysical importance on radiative capture reactions. We also review some of the important historical advances in the field of recoil separators as well as describe current techniques and performance milestones, including descriptions of some of the separators most recently working at radioactive ion beam facilities, such as DRAGON at TRIUMF and the DRS at the Holifield Radioactive Ion Beam Facility. We will also summarize some of the scientific highlight measurements at the RIB facilities. (orig.)

Process for hardening an alkyd resin composition using ionizing radiation. [electron beams, gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Watanabe, T; Murata, K; Maruyama, T

1969-11-27

In an alkyd resin composition having free hydroxide radicals and containing a conjugated unsaturated fatty acid and/or oil as a component thereof, a process for hardening an alkyd resin composition comprises the steps of dissolving into a vinyl monomer, the product obtained by the semi-esterification reaction of said hydroxide radicals with acid anhydrides having polymerizable radicals and hardening by ionizing radiation to provide a coating with a high degree of cross-linking, with favorable properties such as toughness, hardness, chemical resistance and resistance to weather and with the feasibility of being applied as the ground and finish coat on metals, wood, paper, outdoor construction or the like. Any kind of ionization radiation, particularly accelerated electron beams, ..gamma.. radiation can be used at 50/sup 0/C to -5/sup 0/C for a few seconds or minutes, permitting continuous operation. In one example, 384 parts of phthalic anhydride, 115 parts of pentaerythritol, 233 parts of trimethylol ethane, 288 parts of tung fatty acid and 49 parts of para-tertiary-butyl benzoic acid are mixed and heated with 60 parts of xylene to an acid value of 12. In addition, 271 parts of maleic anhydride and 0.6 parts of hydroquinone are admixed with the content and heated to terminate the reaction. 100 parts of a 50% stylene solution of this alkyd resin are mixed with 1 part of a 60% toluene solution of cobalt naphthenate, and then coated on a glass plate and irradiated with high energy electron beams of 300 kV with a dose of 5 Mrad for 1 sec.

Treatment of Head and Neck Paragangliomas With External Beam Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Dupin, Charles, E-mail: c.dupin@bordeaux.unicancer.fr [Department of Radiotherapy, Comprehensive Cancer Center, Institut Bergonié, Bordeaux (France); Lang, Philippe [Department of Radiotherapy, Pitié Salpétrière, Paris (France); Dessard-Diana, Bernadette [Department of Radiotherapy, Hopital Européen Georges Pompidou, Paris (France); Simon, Jean-Marc; Cuenca, Xavier; Mazeron, Jean-Jacques; Feuvret, Loïc [Department of Radiotherapy, Pitié Salpétrière, Paris (France)

2014-06-01

Purpose: To retrospectively assess the outcomes of radiation therapy in patients with head and neck paragangliomas. Methods and Materials: From 1990 to 2009, 66 patients with 81 head and neck paragangliomas were treated by conventional external beam radiation therapy in 25 fractions at a median dose of 45 Gy (range, 41.4-68 Gy). One case was malignant. The median gross target volume and planning target volume were 30 cm{sup 3} (range, 0.9-243 cm{sup 3}) and 116 cm{sup 3} (range, 24-731 cm{sup 3}), respectively. Median age was 57.4 years (range, 15-84 years). Eleven patients had multicentric lesions, and 8 had family histories of paraganglioma. Paragangliomas were located in the temporal bone, the carotid body, and the glomus vagal in 51, 18, and 10 patients, respectively. Forty-six patients had exclusive radiation therapy, and 20 had salvage radiation therapy. The median follow-up was 4.1 years (range, 0.1-21.2 years). Results: One patient had a recurrence of temporal bone paraganglioma 8 years after treatment. The actuarial local control rates were 100% at 5 years and 98.7% at 10 years. Patients with multifocal tumors and family histories were significantly younger (42 years vs 58 years [P=.002] and 37 years vs 58 years [P=.0003], respectively). The association between family predisposition and multifocality was significant (P<.001). Two patients had cause-specific death within the 6 months after irradiation. During radiation therapy, 9 patients required hospitalization for weight loss, nausea, mucositis, or ophthalmic zoster. Two late vascular complications occurred (middle cerebral artery and carotid stenosis), and 2 late radiation-related meningiomas appeared 15 and 18 years after treatment. Conclusion: Conventional external beam radiation therapy is an effective and safe treatment option that achieves excellent local control; it should be considered as a first-line treatment of choice for head and neck paragangliomas.

Antioxidants attenuate atherosclerotic plaque development in a balloon-denuded and -radiated hypercholesterolemic rabbit

International Nuclear Information System (INIS)

Leborgne, Laurent; Fournadjiev, Jana; Pakala, Rajbabu; Dilcher, Christian; Cheneau, Edouard; Wolfram, Roswitha; Hellinga, David; Seaborn, Rufus; O'Tio, Fermin; Waksman, Ron

2003-01-01

Background: Oxidation of lipoproteins is considered to be a key contributor to atherogenesis. Antioxidants are potential antiatherogenic agents because they can inhibit lipoprotein oxidation. Radiation has been shown to increase oxidative stress leading to increased atherogenesis. This study is designed to test the potential of antioxidants to inhibit atherosclerotic plaque progression in balloon-denuded and -radiated rabbits. Methods and Results: Two groups of New Zealand white rabbits (n=36) were fed with 1% cholesterol diet (control diet) or with 1% cholesterol diet containing a mixture of various antioxidants for 1 week. Iliac arteries in all the animals were balloon denuded and continued to fed with 0.15% cholesterol diet or 0.15% cholesterol diet containing antioxidants (antioxidant diet). Four weeks after balloon denudation one iliac artery in 12 animals from each group was radiated and all the animals were continued to be fed with the same diet. Four weeks after radiation animals were sacrificed and morphometric analysis of iliac arteries (n=12) in nonradiated and radiated animals were performed. Plaque area (PA) in the rabbits that were fed with cholesterol diet is 0.2±0.12 mm 2 , and it is increased by 2.75-fold (P<.05) in the radiated arteries of animals fed with cholesterol diet. Plaque area in the animals fed with antioxidant diet is 50% less then the one in the animals fed with cholesterol diet. Similarly, plaque area in radiated arteries of the animals fed with antioxidant diet is 50% less then the animals fed with cholesterol diet. Conclusion: Antioxidants significantly attenuate atherosclerotic plaque progression in balloon-injured and -radiated hypercholesterolemic rabbits

Study of Textile Surface Characteristic Modification by Using Electron Beam Radiation

International Nuclear Information System (INIS)

Iswani Gitawati; Rany Saptaaji

2007-01-01

The success of accelerator technology application in various field of industry, medical and pharmacy, environment, agricultural, food increase each year as the increasing of people needs, not excepted for surface treatment of fibers and textiles in textile industry. This writing aim is to asses the application of electron beam accelerator for textile surface treatment on finishing step. Surface treatment was done with electron beam low energy (100 - 500 keV), and because of its low penetration it was suitable used to gain the improvement of chemical, physical and mechanical properties of textile surface such as adhesion, wettability, printability, dyes-intake, crease recovery, wrinkle-resistance, flammability, abrasion resistance, soil and stain release to get better result. Modification of fibers and textiles surface properties on finishing process can be caused by crosslinking, grafting and degradation reactions. The assesment results showed that the greatest impact on commercial application of radiation in textiles were crease recovery and surface modification of wetting properties (soil and stain release). The radiation dose used for those purposes were 5 - 50 kGy. The bach process of graft textiles surface modification before and after irradiation by Co-60 source (gamma energies of 1.33 and 1.17 MeV) and continue process by electron beam were presented. The assesment results were reported in this paper. (author)

Acousto-optic measurements of ultrasound attenuation in tellurium dioxide crystal

International Nuclear Information System (INIS)

Voloshinov, V. B.; Lemyaskina, E. A.

1996-01-01

The paper is devoted to experimental investigation of ultrasound propagation in tellurium dioxide monocrystal. In particular, attenuation of slow shear acoustic modes in the crystal was measured. The measurements were performed by acousto-optic methods using probing of acoustic column by a laser beam. The paper describes measurements of acoustic attenuation coefficient for slow shear ultrasonic waves propagating at an angle =4.5 O with respect to the (110) direction in the (110) plane. The investigation was made at acoustic frequency f = 100 MHz with pulsed acoustic waves and with an optical beam of a He-Ne laser. It is found that the attenuation coefficient is α = 0.57 cm -1 ± 15 %. The attenuation at acoustic frequencies f ≥ 100 MHz influences performance characteristics of acousto-optical devices based on tellurium dioxide. As proved, spectral resolution of a quasicollinear acoustooptic filter decreases by a factor of 2 compared to a case of the attenuation absence. (authors)

Photon beam audits for radiation therapy clinics: A pilot mailed dosemeter study in Turkey

International Nuclear Information System (INIS)

Yegingil, Z.; DeWerd, L. A.; Davis, S. D.; Hammer, C.; Kunugi, K.

2012-01-01

A thermoluminescent dosemeter (TLD) mailed dose audit programme was performed at five radiotherapy clinics in Turkey. The intercomparison was organised by the Univ. of Wisconsin Radiation Calibration Laboratory (UWRCL), which was responsible for the technical aspects of the study including reference irradiations, distribution, collection and evaluation. The purpose of these audits was to perform an independent dosimetry check of the radiation beams using TLDs sent by mail. Acrylic holders, each with five TLD chips inside and instructions for their irradiation to specified absorbed dose to water of 2 Gy, were mailed to all participating clinics. TLD irradiations were performed with a 6 MV linear accelerator and 60 Co photon beams. The deviations from the TL readings of UWRCL were calculated. Discrepancies inside the limits of ±5 % between the participant-stated dose, and the TLD-measured dose were considered acceptable. One out of 10 beams checked was outside this limit, with a difference of 5.8 %. (authors)

Development and application of a dosimetric methodology of therapeutic X radiation beams using a tandem system

International Nuclear Information System (INIS)

Sartoris, Carla Eri

2001-01-01

In radiotherapy the use of orthovoltage X radiation beams is still recommended; to obtain satisfactory results, a periodic control is necessary to check the performance of the ionization chambers and the radiation beams characteristics. This control is performed by using standard dosimetric procedures, as for example the determination of half-value layers and the absorbed dose rates. A Tandem system was established in this work using a pair of ionization chambers (a thimble type and a superficial type) used for measures in a medical institution, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The results obtained show the application of this method in dosimetric procedures of orthovoltage beams (radiotherapy) as a complement for a quality control program. (author)

Feasibility of Optical Transition Radiation Imaging for Laser-driven Plasma Accelerator Electron-Beam Diagnostics

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A. H. [Fermilab; Rule, D. W. [Unlisted, US, MD; Downer, M. C. [Texas U.

2017-10-09

We report the initial considerations of using linearly polarized optical transition radiation (OTR) to characterize the electron beams of laser plasma accelerators (LPAs) such as at the Univ. of Texas at Austin. The two LPAs operate at 100 MeV and 2-GeV, and they currently have estimated normalized emittances at ~ 1-mm mrad regime with beam divergences less than 1/γ and beam sizes to be determined at the micron level. Analytical modeling results indicate the feasibility of using these OTR techniques for the LPA applications.

Radiation transport calculations for the ANS [Advanced Neutron Source] beam tubes

International Nuclear Information System (INIS)

Engle, W.W. Jr.; Lillie, R.A.; Slater, C.O.

1988-01-01

The Advanced Neutron Source facility (ANS) will incorporate a large number of both radial and no-line-of-sight (NLS) beam tubes to provide very large thermal neutron fluxes to experimental facilities. The purpose of this work was to obtain comparisons for the ANS single- and split-core designs of the thermal and damage neutron and gamma-ray scalar fluxes in these beams tubes. For experimental locations far from the reactor cores, angular flux data are required; however, for close-in experimental locations, the scalar fluxes within each beam tube provide a credible estimate of the various signal to noise ratios. In this paper, the coupled two- and three-dimensional radiation transport calculations employed to estimate the scalar neutron and gamma-ray fluxes will be described and the results from these calculations will be discussed. 6 refs., 2 figs

Behavior of MOSFET Amplifier in Radiation Fields

International Nuclear Information System (INIS)

Sharshar, K.A.A.; Ashry, M.

2000-01-01

MOSFET type 2 N 3823 characteristics and its application as an amplifier are analyzed including the effects of gamma, electron beam 1.5 MeV 25 m A and neutron flux. The 1-V characteristics, transfer curve, and the frequency response of the amplifier, and the amplification factor(A v 0 are discussed with MOSFET circuit parameters. The drain current and the amplitude of the output signal decrease as the absorbed dose increases. The measured values of the amplified signal are attenuated by 30% and 6% after exposing the MOSFET to gamma radiation and electron beam at the same dose respectively. Also for exposure to 4x10 13 N/cm 3 neutrons decreased the measured value of the amplified signal by 73% of the initial values. The decrease in the gain of the MOSFET is due to the degradation of the transconductance. It is also noticed that percentage of the decrease depends on the type of radiation

Beta attenuation transmission system (BATS)

Energy Technology Data Exchange (ETDEWEB)

Hagan, R.C.; Fullbright, H.J.

1977-01-01

The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm/sup 2/, of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A /sup 90/Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (..mu..P) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined.

Beta attenuation transmission system (BATS)

International Nuclear Information System (INIS)

Hagan, R.C.; Fullbright, H.J.

1977-01-01

The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm 2 , of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A 90 Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (μP) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined

Synchrotron radiation leakage from the B-factory beam pipe

International Nuclear Information System (INIS)

Jenkins, T.M.; Nelson, W.R.; Ipe, N.

1990-01-01

The high-energy ring (HER) of the B-Factory, running at an energy of 9 GeV, generates the synchrotron spectrum when applied to a ring with the PEP bending radius. The B-Factory HER may also run at 12 GeV, producing the harder spectrum. Depending upon beam-pipe material and thickness, some of this radiation may escape and deposit energy in the surrounding material. This was originally pointed out in PEP-109 during the initial design of PEP, and subsequently verified by measurements at both PEP and PETRA at DESY. Of concern to the B Factory is magnet insulation, though other adjacent materials such as wire insulation and cooling water hoses are even more radiosensitive. Radiation damage to magnets is a function of the type of material used in the potting compound. The PEP magnets, which hopefully can be used for the high-energy ring of the B-Factory, are insulated with an epoxy composed of DER-332, DER-732, NMA and aluminum oxide. It is estimated that this epoxy compound should tolerate doses near the 10 10 rad range. To summarize the results of these calculations, 0.87 cm of copper is needed at the point of maximum dose from 12-GeV operation in order to reach the dose criterion if a rectangular beam pipe is used. The copper needs to be only 0.7-cm thick for an octagonal beam pipe and the same energy. For 9-GeV operation, an octagonal copper pipe needs only to be 0.25-cm thick. An octagonal aluminum pipe that is 0.5-cm thick also needs 0.3 cm of lead on the outside to reach the same criterion for 12-GeV operation. For 9-GeV operation, the aluminum pipe still requires a lead liner