Measurements have been made on a Siemens Mevatron 67 linear accelerator. The change of beam quality has been measured as a function of position off-axis and compared to another Siemens 6 MV linear accelerator. Similarly, beam profiles are compared to a Siemens Mevatron VI. Additional measurements include entrance ...
Energy Citations Database
The work described in this thesis deals in the first part with the initial dosimetry work which has to be accomplished when receiving a linear accelerator for use in therapy. The authors worked with the ''MEVATRON'' (8MV photons) in a water phantom, using...
National Technical Information Service (NTIS)
In the study of vaccum parameter system in the structure of a linear electron accelerator feeded by radio-frequency, the periodical release of adsorbed gases should be considered. For high power machines a structure inside a vaccum shield are recommended....
The Pelletron-Linac accelerator of the University of Sao Paulo will use the existing electrostatic Pelletron accelerator as an injector for the linear superconducting accelerator (Linac), to increase the acceleration of the particles. The Linac uses a for...
In this work a different system is proposed which is able to verify the absorbed depth dose given at two different depths, the irradiation field homogeneity and its coincidence with the light field of the machine, the source to surface distance used and t...
Elaboration of such a simple technique for total skin electron irradiation which ensures good dose homogeneity and minimal x-ray background dose. MATERIALS AND METHODS: We started large electron field irradiations with the Neptun 10p linear accelerator in the National Institute of Oncology -Budapest in 1986. After the installation of the Siemens Mevatron ...
PubMed
The 15-MV photon beam of a linear accelerator (Siemens Mevatron 20) was studied for electron and scattered photon contamination. The surface dose, attributable almost entirely to contamination electrons, has a Gaussian lateral distribution, a linear dependence on field width for square fields, and an inverse square dependence on ...
Fast neutron contamination in photon beams in the 20 MV range have been reported in recent years. In order to determine if the variations were due mainly to differences in measurement procedures, or inherent in the design of the accelerators, three different 18-MV (BJR) photon beams were compared using identical analytical techniques. The units studied were a Philips SL/75-20 and a Siemens ...
Parameters of the photon beams (6 and 20 MV) from a dual-energy linear accelerator (Mevatron-KD, Siemens Medical Laboratories, CA) are presented. The depth dose characteristics of the photon beams are d/sub max/ of 1.8 and 3.8 cm and percentage depth dose of 68% and 80% at 10-cm depth and 100-cm source--surface distance for a field size of 10 x 10 cm/sup ...
To determine the cause of increased skin reactions near the edges of the field the authors measured doses at and near the surface of the skin with an extrapolation chamber for the gamma-ray beam of an AECL Eldorado 8 $sup 60$Co $gamma$ irradiator and the x-ray beams of a Varian Clinac 4 linear accelerator, a Varian Clinac 6 linear accelerator, and ...
A laminated beam-spot camera of length 20 cm and effective cross-sectional area 2.5 cm � 3 cm was designed and constructed for the measurement of X-ray beam-spot sizes on different models of Siemens accelerators. With the accelerator gantry at 180� and camera positioned on an accessory tray holder, an XV film placed in contact with the camera at the distal end of it detected those X-rays that ...
The high energy electrons produced by linear accelerators can generate several radioisotopes by means of photonuclear reactions. The activity produced in the head of a 15 MV Mevatron Siemens 77 medical linear accelerator was measured by high resolution gamma-ray spectrometry, during its decommissioning 1 year after the last clinical ...
The original scattering and collimation system for the Siemens Mevatron XII linear accelerator used a lead scattering foil and box-type plastic collimators. This arrangement achieves excellent field flatness by repeated electron scattering. The electrons reaching the patient are widely distributed in energy and direction. This has detrimental effects on ...
Dosimetric properties for stereotaxic convergent beam therapy techniques with small field sizes have been investigated as well as for the linear accelerator Mevatron 77 as for the neutron generator KARIN. Additionally we also measured the dose distribution of single plane rotational therapy. As an indication of quality we calculated the V50 ratio as V50 = ...
The document includes the programme and the 10 abstracts of the 2. Mexican national meeting on accelerators. A separate indexing is provided for each abstract. (Atomindex citation 24:064160)
BACKGROUND AND PURPOSE: In radiotherapy with electron linear accelerators, it is mandatory to guarantee the stability of beam output spectra. In this work we study the quality control of the magnitude that provides the beam spectral quality, by following statistical techniques usual in industry process. METHODS: We establish the differences between the measurement of the ...
In the past, the Radiological Physics Center (RPC) has developed standard sets of photon depth-dose and wedge-factor data, specific to the make, model, and wedge design of the linear accelerator (linac). In this paper, the RPC extends the same concept to electron-cone ratios. Since 1987, the RPC has measured and documented cone-ratio (CR) values during on-site dosimetry review ...
A Siemens Mevatron KV2 accelerator installed at the Royal Adelaide Hospital employs cylindrical solid-walled electron cones for some electron collimation. The cones being used at present result in treatment fields that do not always conform with the International Electrotechnical Commission (IEC) Standards (particularly at high energies). The aim of this project was to ...
Monte Carlo (MC) methods are nowadays often used in the field of radiotherapy. Through successive steps, radiation fields are simulated, producing source Phase Space Data (PSD) that enable a dose calculation with good accuracy. Narrow photon beams used in radiosurgery can also be simulated by MC codes. However, the poor efficiency in simulating these narrow photon beams produces PSD whose quality ...
An international conference on polonium (Po) and radioactive isotopes was held in Seville Spain, 26-28 October 2009 at the Centro Nacional de Aceleradores. It was attended by 138 participants from 38 different countries. The sessions covered all aspects on Po and lead (Pb) such as radiochemistry, terrestrial and marine radioecology, kinetics, sedimentation rates, atmospheric ...
The sulfur hexafluoride is the better dielectric gas in the world. It is used in particle accelerators, power stations and high voltage transformators. This is a high stable gas, but when is it used as dielectric is degraded in toxic and corrosive fluorid...
An accelerator for the generation of low energy electrons (in the 0.4 to 20 keV range) was constructed. The accelerator is equipped with some devices especially designed for the investigation of the electrical properties of electron-irradiated dielectrics...
The performance of an L-alanine dosimeter with millimeter dimensions was evaluated for dosimetry in small radiation fields. Relative output factor (ROF) measurements were made for 0.5x0.5, 1x1, 3x3, 5x5, 10x10 cm{sup 2} square fields and for 5-, 10-, 20-, 40-mm-diam circular fields. In beam profile (BP) measurements, only 1x1, 3x3, 5x5 cm{sup 2} square fields and 10-, 20-, 40-mm-diam circular ...
Since February 2006, the new 1 MV multielement compact AMS facility SARA (Spanish Accelerator for Radionuclides Analyses) at the Centro Nacional de Aceleradores (CNA) in Sevilla (Spain) is fully operative. During the first one and a half year of operation, the viability of the system for the measurement of 10Be, 14C, 129I and plutonium isotopes, 239Pu and 240Pu, has been ...
NASA Astrophysics Data System (ADS)
Plutonium isotopes have been recently added to the list of radionuclides that can be measured with the new generation of compact AMS facilities. In this paper we present first experimental results concerning the development of the plutonium AMS technique at 680 kV on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA) in Sevilla, Spain. This is the first compact ...
Samples of drinking water and waste water were irradiated using high energy electron beam with doses from 0.37kGy to 100kGy. Preliminary data show the removal of about 100% tri halomethanes (THM) in drinking water concentration from 2.7 (mu)g/1 to 45(mu)g...
In this work we present the most recent improvements performed by our group on 10Be measurements on the 1 MV AMS system recently set up at the CNA (Centro Nacional de Aceleradores), in Seville (Spain). Our efforts have been focused on the study of the viability of our system for BeO and BeF- measurements. To achieve this, different standard materials have been measured to ...
In February 1998, almost 10 years ago, the set-up of the first IBA (ion beam analysis) facility in Spain took place with the arrival of a 3 MV tandem accelerator [J. Garc�a-L�pez, F.J. Ager, M. Barbadillo-Rank, F.J. Madrigal, M.A. Ontalba, M.A. Respaldiza, M.D. Ynsa, Nucl. Instr. and Meth. B 161 163 (2000) 1137]. Since then, an intensive research program using IBA techniques has been carried ...
