Production rates of the activation of oxygen and nitrogen by high-energy x-ray beams from medical accelerators were measured as functions of the accelerator energy. A technique was developed in which the air-activation production rates are used to evaluate the concentration of radioactive gas in the treatment room and the ...

Dose rates at several locations outside a treatment room were measured for 6 and 18 MV photon beams from a Varian Clinac 21EX accelerator operated with and without a flattening filter. Also, dose rates in the treatment room due to activation were measured at 18 MV. An analysis of the measured ...

During X-ray therapeutic irradiation with energies above the threshold of (X,n) reactions in the structural materials of medical accelerators, a photoneutron fluence is generated. In Brazil, no measurements of neutron doses in radiotherapy rooms are being done yet, when licensing these equipment. Consequently, it is very important to ...

The neutron leakage from medical and industrial electron accelerators has become an important problem and its detection and shielding is being performed in their facilities. This study provides a new simple method of design calculation for neutron shielding of those electron accelerator facilities by dividing into the following five categories; neutron ...

When space limitations are primary constraints, laminated barriers with metals can be an option to provide sufficient shielding for a radiotherapy treatment room. However, if a photon clinical beam with end point energy of 10 MeV or higher interacts with the metal inside the barriers neutrons are ejected and can result in an exposure problem inside and outside the vault. The ...

When space limitations are primary constraints, laminated barriers with metals can be an option to provide sufficient shielding for a radiotherapy treatment room. However, if a photon clinical beam with end point energy of 10 MeV or higher interacts with the metal inside the barriers neutrons are ejected and can result in an exposure problem inside and outside the vault. The ...

For medical accelerators, neutron penetration through the room entry door is the major personnel hazard. Most therapy accelerator rooms are designed with at least a rudimentary maze to avoid the use of massive doors. Often, however, the maze may be similar to those shown in scale outline drawings of some medical ...

The electron linear accelerator was first used to generate X-rays for radiation therapy in the early 1950s and is today the main type of machine used in this field. This book provides knowledge of a wide range of technology involved in the design and operation of linear accelerations for radiotherapy, and of the very exacting conditions imposed by the ...

In this paper, the general-purpose Monte Carlo code MCNP5 was used to study the dose variance due to the position of medical linear accelerators, under unusual conditions, for shielding design of radiotherapy facilities. It was found that the computational methods generally used to estimate the scattered photon doses at the entrance of ...

This paper evaluates the accuracy of Kersey's method of calculation of the dose level due to photoneutrons at the maze entrance of medical accelerators. In this study measurements and calculations of the neutron dose equivalent were made for 13 medical accelerator facilities. The group of ...

Dedicated accelerators for intra-operative radiation therapy (IORT) are operated at high dose rates in order to achieve short treatment times within which the anaesthetisized patient must be remotely monitored (e.g. via video cameras and telemetric anesthesia instruments). Due to these high dose rates, large doses ...

A radiation streaming experiment has been carried out at the Takasaki Ion Accelerator Facility for Advanced Radiation Application at the Japan Atomic Energy Research Institute in a room housing a Cu target irradiated with 68 MeV protons and in a labyrinth of three-legs having a total length of 29 m. In the experiment, neutron and gamma ray energy spectra, ...

A method is described using simple gold foils and relatively inexpensive moderators to measure neutron fluences, both fast nd thermal, which then can be converted to dose equivalent using a few simple formulas. The method is sensitive, easy to calibrate, and should work at most accelerators regardless of energy or room geometry.

Neutron doses often come dominant in mazes of electron accelerator facilities in which X-rays of energies more than 10 MV are produced. A simple analytical method to calculate neutron doses in such a facility is developed. In the calculation procedure, it is assumed that the irradiation room is spherical in shape ...

Several radiation surveys, at medical linear accelerator facilities where lead or steel had been used with concrete to fabricate the primary barriers, revealed the existence of a sizable neutron field outside the shielding. This neutron field is produced by photoneutrons generated in the metal portion of the shield when the primary x-ray beam is aimed at the barrier. A method ...

The production of photoneutrons by electron accelerators is an unavoidable process at operating energies above about 10 MeV. These photoneutrons create problems in shielding, personnel protection, and induced radioactivity. This paper attempts to describe the neutron field spectral and intensity distributions. The initial spectrum and modifying effects of photon shielding ...

The characteristics of activation after high-energy X-rays have been generated by medical linear accelerators were measured using an ionization chamber. Radiation doses increased with rising X-ray energy, based on 10 MV, 15 MV, and 18 MVX-ray measurements. When the total irradiation dose was changed, radiation dose ...

The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. Measured data obtained at a variety of accelerator installations are presented and compared with these calculations. It is found that the ...

For the accelerator production of tritium (APT), the accelerator driven transmutation facility (ADTF), and the advanced fuel cycle initiative (AFCI), tungsten is being proposed as a target material to produce neutrons. In this study, tungsten rods were irradiated at the 800 MeV Los Alamos Neutron Science Center (LANSCE) proton ...

The photoneutron contamination arising from a high-energy medical lineal accelerator is calculated using Monte Carlo simulation, as a function of the radiation field size. The information is used to model the neutron propagation in a radiotherapy treatment room and the transmission across concrete mazes. The Monte Carlo code MCNP4C is used to model the ...

The photoneutron contamination arising from a high-energy medical lineal accelerator is calculated using Monte Carlo simulation, as a function of the radiation field size. The information is used to model the neutron propagation in a radiotherapy treatment room and the transmission across concrete mazes. The Monte Carlo code MCNP4C is used to model the ...

In a previous work, the authors and colleagues studied problems of photoneutron transport in concrete rooms using the Monte Carlo transport program, MORSE and supporting experimental measurements. From this work, an empirical method of calculation was developed based on the average energy, anti E, of the neutron spectrum. Using this method, it is possible to calculate the ...

In this work, we investigate the relation between lateral fluence/dose distributions and photon beam uniformity, possibly identifying ways to improve these characteristics. The calculations included treatment head scatter properties associated with three common types of linear accelerators in order to study their impact on the results. For 6 and 18 MV ...

In this work, we investigate the relation between lateral fluence/dose distributions and photon beam uniformity, possibly identifying ways to improve these characteristics. The calculations included treatment head scatter properties associated with three common types of linear accelerators in order to study their impact on the results. For 6 and 18 MV ...

MCNP code was used to simulate neutron and prompt gamma ray transport for a range of maze geometrical parameters, wall composition, and wall surface lining. Verification measurements were performed at two medical electron accelerator facilities. A very good agreement was observed between the results of the measurements and the MCNP simulation. MCNP code results were compared ...

The Brazilian national regulatory authority, National Commission of Nuclear Energy, requires that dose rates in the vicinity of teletherapy treatment rooms do not exceed the permissible limits for workers as well as members of the public, depending on the place considered. At the end of 2005, the Brazilian national regulatory authority reduced the ...

... 4) pulsed power accelerators, (5) high intensity accelerators, (6) room temperature magnets, (7) electron linear, (8) linear accelerators, (9) new ...

Currently, teletherapy machines of cobalt and caesium are being replaced by linear accelerators. The maximum photon energy in these machines can vary from 4 to 25 MeV, and one of the great advantages of these equipments is that they do not have a radioactive source incorporated. High-energy (E > 10 MV) medical linear accelerators offer several physical ...

Medical accelerators operating at an energy above 10 Mev produce a significant amount of photoneutrons. These undesirable neutrons are difficult to measure due to the presence of high intensity and high energy photons. Because of the uncertainty of the dose level, these photoneutrons create problems in room shielding, personnel ...

The use of a 4 MV linear accelerator for whole body irradiation is described in this study. The room size limits the focus to skin distance to 279 cm. At this distance a maximum field length of 162 cm is achieved by: (a) using the diagonal of the beam by rotating the collimator 45/sup 0/; (b) adding a special flattening filter which increases the useful ...

We developed a neutron irradiation facility, neutron exposure accelerator system for biological effect experiments (NASBEE) for biological studies in National Institute of Radiological Sciences, Japan. Irradiation field of 2 MeV average neutrons generated by a Be(d-n)B reaction is established. Dose uniformity of 240 mm in diameter irradiation field is ...

This study of doses to patients from emitted photoneutrons in a medical linear accelerator (Varian 2100C) was carried out. Dose calculation was performed using Monte Carlo Geant4 code. The model was used to calculate the neutron fluence, as a function of the neutron energy inside the treatment room to estimate the ...

A doubling in personnel monitoring doses around medical accelerators has been reported when monthly film badges were changed to quarterly thermoluminescent (TL) dosimeters. One possible explanation for the inconsistent results is the response of LiF to thermal neutrons coming through the shielding around the accelerator. To test for ...

The heavy ion irradiation simulation technique has been developed at the HI-13 tandem accelerator and used to investigate radiation damage in modified stainless steel, tungsten and tantalum at irradiation temperatures from room temperature to 800�C and in the irradiation dose region up to 100 dpa. The experimental results are ...

Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the 60Co isotope approach. However, the ...

A new beam line for radiotherapy and radiosurgery with accelerated helium-ion beams has been set up at the Bevalac. The new treatment room has been equipped with a very precise patient positioner in order to utilize the superior dose localization properties of light-ion beams. The beam spreading and shaping system is described, the ...

Radiation-induced changes in hydroxypropyl methylcellulose (HPMC) films under electron irradiation were investigated and correlated with dose. Polymer samples were irradiated in air at room temperature by an electron beam accelerator in the range of 0-100 kGy. Various properties of the irradiated films were studied using a ...

The article studied the methods how to shorten the irradiation time by increasing dose rate without changing the relationship between dose versus properties of degraded samples. The samples used were nine kinds of EPDM which have different compounding formula. The different dose of Co-? ray was exposed to the samples. The maximum ...

When high-energy photon beams are used for irradiation in radiotherapy, neutrons that are the result of photonuclear reactions create activation products that affect the occupational dose of radiotherapy staff. For the assessment of activation products in situ gamma spectroscopy was performed parallel to dose-rate measurements following irradiation, by ...

In this work, the energy spectra of photoneutrons, scattered by ordinary, high-density concrete and wood barriers, have been evaluated using the MCNP4B code. These spectra were calculated for different scattering angles, and for incident neutron energies varying between 0.1 and 10 MeV. The results presented are required to simulate typical photoneutron fluence, produced by medical ...

An easily applicable empirical formula was derived for use in the assessment of the photoneutron dose at the maze entrance of a 15 MV medical accelerator treatment room. The neutron dose equivalent rates around the Varian medical accelerator head calculated with the Monte Carlo code MCNPX were ...

The doses and spectra of photoneutrons produced in a medical linear accelerator with photon energies of 10 and 15 MV were evaluated. The Monte Carlo code, MCNPX, was used to simulate the transport of these photoneutrons around the head for 10 and 15 MV photons. The fully-described geometry of the accelerator head was used in this ...

The use of commercial window glass as possible high dose routine dosimeter has been investigated. Glass samples have been irradiated with doses in the range of 1-50 kGy using 60Co ? source, 4 MeV and 12 MeV electron accelerators. The samples were given a post irradiation thermal treatment (150 �C for 20 min) in order to improve the ...

Motion sickness studied with slow rotation room having controlled Coriolis accelerations, discussing

... mixing]. Doses were prepared within X days of dosing and were stored [eg, with constant stirring at room temperature]. ...

Requirements governing the de sign of high-pressure oxygen equipment for use in radiotherapy are discussed and one such barotherapy apparatus is described and illustrated. This apparatus, manufactured by the Commonwealth Aircraft Corporation for the Peter MacCallum Clinic, Melbourne, is designed to operate at pressures of 60 psi oxygen (or less) in conjunction with a 4-Mev linear ...

Under this CRADA, Berkeley Lab and the industry partner, General Atomics (GA), have cooperatively developed hadron therapy technologies for commercialization. Specifically, Berkeley Lab and GA jointly developed beam transport systems to bring the extracted protons from the accelerator to the treatment rooms, rotating gantries to aim the treatment beams ...

The grafting of methacrylic acid, styrene (2: 1 mole ratio) co-monomer mixture on polypropylene film and fabric, was studied to compare electron accelerators and isotopes as sources of radiation. An aluminum block that contalns i/8-in.-deep pockets covered with Mylar film for holding sample and monomer during mutual irradiatlon was developed. A preliminary comparison ...

The research program of the Physics Division's tandem Van de Graaff accelerator facility at Argonne National Laboratory often requires entries into a target room while the accelerator beam is present, both to perform adjustments on an experiment in progress and to set up a future experiment on another beam line. To assure the ...

The topics of this volume include: (1) electron storage rings and circular accelerators, (2) accelerators and storage rings, other, (3) superconducting magnets, (4) pulsed power accelerators, (5) high intensity accelerators, (6) room temperature magnets, ...

For medical accelerators, neutron penetration through the room entry door is the major personnel hazard. Most therapy accelerator rooms are designed with at least a rudimentary maze to avoid the use of massive doors. Often, however, the maze may be simila...

The photoneutrons produced by high-energy x-ray machines can diffuse through the mazes usually employed at the treatment-room entrance and readily penetrate the lead-lined doors used for x-ray shielding. The measurement of these neutrons in the presence of x-rays and the determination of dose equivalent poses a problem for which there is currently no ...

A method of evaluating the photoneutron fluence in the maze of accelerator facilities due to room scattered neutrons is presented. Measurements were made to demonstrate that the room scattered fluence is reduced by a factor of 2pi in going from the treatment room to the inner maze entrance. PMID:10076975

Two cable types, which currently are used in nuclear power plants (NPP) and which are composed by jacket/insulation materials, i.e. PVC/PVC and PVC/PE, were exposed to accelerated ageing conditions, in order to simulate their behavior after 10 years in service. The cables were aged under two different test conditions:With relatively high accelerating ...

In Brazil, the replacement of rather old cobalt and cesium teletherapy machines with high-energy (E > 10 MV) medical linear accelerators (linacs) started in the year 2000, as part of an effort by the Ministry of Health to update radiotherapy installations. Since then, the contamination of undesirable neutrons in the therapeutic beam generated by these high-energy photons ...

Abstract An increasing number of proton therapy facilities are being planned and built at hospital based centers. Most facilities are employing traditional dose delivery methods. A second generation of dose application techniques, based on pencil beam scanning, is slowly being introduced into the commercially available proton therapy systems. New ...

The Indiana University Cyclotron Facility houses three research accelerators (a 205-MeV cyclotron, a 240-MeV synchrotron, and a 500-MeV synchrotron) with space to carry out a program of fundamental and applied research including nuclear and accelerator physics, materials science, radiation biology, and proton therapy. Twelve thousand square feet associated ...

Transmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments have been performed in situ by using the HVEM - Ion Accelerator Facility at Argonne National Laboratory. The ion bombardments (50 keV Ar/sup +/ and Kr/sup +/) and the microscopy have been carried out at temperatures ...

A room Co-60 source was characterized using TLDs and pMOS RADFETs. Dose enhancement was measured using RADFETs with and without gold- flashed kovar lids. A methodology was developed to predict dose enhancement vs position and test configuration.

Dopa accumulation was accelerated by tyrosine administration, ... A low dose of phenylalanine elevated brain tyrosine without accelerating dopa synthesis. ...

Charged Particle Therapy (the use of protons and other light ions such as carbon to treat certain forms of cancer) is experiencing a rapid expansion in many parts of the world, and there are now more than 30 such centres operating in hospitals. The current technologies available use cyclotrons and synchrotrons to deliver the dose to the cancer. While each of these technologies ...

In order to investigate the effect of the damage on the electrochemical behavior, zircaloy-4 specimens were irradiated by Ar ions using an accelerator at an energy of 50 keV, with doses from 3 x 10(14) to 3 x 10(16) ions/cm2 at liquid nitrogen temperature. Potentiodynamic polarization measurements were employed to evaluate the corrosion resistance of ...

The measurement of urine plasmin, a proteolytic enzyme, of nurses working in the radium room succeeded in establishing that plasmin is activated even with a slight irradiation of ionizing rays. The activity of plasmin seems to last for a fairly long time. In the case of a slight irradiation no outstanding morphological blood changes are generally noticed. The ...

Raman-scattering experiments on heavily irradiated pure and doped NaCl crystals are described. The experiments have been performed at room temperature and at approximately 25 K. The crystals had been irradiated up to a maximum dose of 95 Grad by means of electrons from a Van de Graaff accelerator. The Raman spectra show the set of ...

A micro-multileaf collimator (microMLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the microMLC does not allow 'direct' imaging of the photon source, special ...

A micro-multileaf collimator (�MLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the �MLC does not allow 'direct' imaging of the photon source, special ...

Activation products are generated from photoneutron capture reactions inside a linear accelerator (LINAC) used in a high energy X-ray cargo inspection facility. The activation products are estimated using MCNPX, Monte Carlo simulation code, in order to evaluate radiological safety in the facility. The result shows that the maximum radiation dose rate from ...

The flexibility of mobile electron accelerators, which are designed to be transported to an operating room and plugged into a normal 3-phase outlet, make them ideal for use in intraoperative radiation therapy. However, their transportability may cause trepidation among potential users, who may question the stability of such an ...

Control room habitability during severe accidents is assessed. The potential levels of radiation hazards to control room personnel are evaluated in terms of magnitude and occurrence probability. The cumulative probability distributions of control room doses, and the expected values for the probabilities of ...

The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are ...

High-energy nickel ion implantation into pure aluminum targets induces local phase transformations. Samples implanted in a TANDEM accelerator at room temperature were studied by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The TEM observations revealed the presence of spherical amorphous zones. In order to understand ...

... can provide the high-brightness electron beams necessary for the FEL: room-temperature pulsed linear accelerators, superconducting accelerators ...

Similar to the power leads of accelerator superconducting magnets, the power couplers of accelerator superconducting cavities are components that link room temperature to superfluid helium temperature for the purpose of energy transfer. Instead of conduct...

HALT Highly Accelerated Life Test. HAST Highly Accelerated Stress Testing. HBT Heterojunction Bipolar Transistor. RT Room Temperature ...

... 102 C.8 Twenty- Four-Hour Gamma Doses in Forward Engine Room (Upper Level) ---- 103 C ... HESS ENGINIE ROOM-'ý ...

oxide, later studies have shown that the dominate factors that affect dose rate sensitivity and the total dose response are the final passivation [7]-[9], ...

... trial, and doses were estimated based on the beam current setting of the accelerator. For each dose, the ... ...

... cool to room temperature. Cooling was accelerated by a stream ... Nitrogen is listed as the principal impurity. Other than the use ...

In 2004, after 14 years of accelerator operations and commissioning, Jefferson Lab renovated its main control room. Changes in technology and lessons learned during those 14 years drove the control room redesign in a new direction, one that optimizes work...

The Control Room Logbook (CRL) is designed to improve and replace the paper logbooks traditionally used in the HEP accelerator control room. Its features benefit the on-line coordinator, the shift operators, and the remote observers. This paper explains s...

Protecting the facility personnel and the general public from radiation exposure is a primary safety concern of an accelerator-based epithermal neutron irradiation facility. This work makes an attempt at answering the questions {open_quotes}How much?{close_quotes} and {open_quotes}What kind?{close_quotes} of shielding will meet the occupational limits of such a facility. ...

A study of the induced activity in a medical linear accelerator (linac) room was carried out on several linac installations. Higher beam energy, higher dose rate, and larger field size generally result in higher activation levels at a given point of interest, while the use of multileaf collimators (MLC) can also increase the activation ...

Using the method of albedo dosimetry, the neutron and photon dose and the mean (effective) neutron energy has been determined in the radiation fields of four different electron accelerators (two linear accelerators, two betatrons). Thermoluminescence-dose...

Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. ...

Fetal exposure to high doses of glucocorticoids slows cellular development and impairs organ performance, in association with growth retardation. Nevertheless, low doses of glucocorticoids may enhance cell differentiation and accelerate specific functions...

There are presented the studies concerning some fresh fruit and vegetable behaviour to ionizing radiations exposure. There were considered: strawberries; cherries; apples; peaches; pears; tomatoes; carrots and other vegetables. It was studied, comparatively, their behaviour to gamma-rays and electron-beam irradiation. The irradiations were performed at a 60Co gamma-ray source and an electron-beam ...

The effect of cold plastic deformation in nickel on the deuterium segregation induced by ion irradiation has been studied by the nuclear-reaction method. The irradiation and discrete measurements have been performed at room temperature and coordinated in time due to the use of a beam of accelerated deuterons with an energy of 700 keV in the reaction D ( ...

A concrete room with a single-legged maze was constructed in order to simulate a medical accelerator room. Gamma and neutron measurements were performed along the maze with (a) a {sup 252}Cf source and (b) a tungsten-moderated {sup 252}Cf source placed inside the room. The measurements were repeated after placing ...

This study considers the radiation safety aspects of several designs discussed in a previous report of an accelerator-based source of neutrons, based on the [sup 7]Li(p,n) reaction, for a Boron Neutron Capture Therapy (BNCT) Facility at Lawrence Berkeley National Laboratory (LBNL). determines the optimal radiation shield thicknesses for the patient treatment ...

The REBEL-3 adjoint Monte Carlo code calculates the doses in the whole body, in the testicles, ovaries, red or yellow marrow, or in the lungs of an inhomogeneous phantom standing in a dwelling room. In addition, it can calculate also the exposure rate in ...

Results and conclusions are reported from a design study for a dedicated medical accelerator. Basing efforts on the current consensus regarding medical requirements, the resulting demands on accelerator and beam delivery systems were analyzed, and existing accelerator technology was reviewed to evaluate the feasibility of meeting these ...

Personnel) Injector Gun 7.7 9.7 Solenoid 12.4 5 Diagnostics 28 15.2 Total Labor Estimate 3045 189 Laser Room solenoid, and laser room, which are industry quotes. �Labor costs (e.g. for the modulator) assume assembly1 Accelerator Research Department BAccelerator Research Department B E163: Laser Acceleration

Electron applicators and cut-outs have been used for some time in the delivery of electron beam therapy. A dual electron multileaf collimator (eMLC) consisting of upper and lower eMLCs was designed, and dose distributions of electron beams delivered by it were evaluated by Monte Carlo simulations by use of the EGSnrc Monte Carlo code. The percentage depth ...

To characterize airborne radioactivity induced by the operation of high-energy accelerators, the fractions of aerosol and gaseous components, and the chemical forms of 11C, 13N, and 15O produced in the air of a target room of a 100 MeV electron linear accelerator were studied. Measurements of radioactivity using a particulate air ...

The indium foil activation technique has been employed to measure thermal neutron fluences (?th) among various locations in the treatment room with a 20�20 cm2 field size and a 15 and 10 MV X-ray beam. Spatial ?th are visualized using colored three-dimensional graphical representations; intensities are up to (1.97�0.13)�105 and (1.46�0.13)�104 n cm-2/Gy-X at ...

One of the key components in modern LINAC room shielding design is the amount of 90 degrees head leakage radiation levels. With the general clinical acceptance of intensity-modulated radiation therapy (IMRT) technique, accurate knowledge of this quantity has become even more important. Measurement of 90 degrees head leakage radiation of medical linear ...

One of the key components in modern LINAC room shielding design is the amount of 90 deg. head leakage radiation levels. With the general clinical acceptance of intensity-modulated radiation therapy (IMRT) technique, accurate knowledge of this quantity has become even more important. Measurement of 90 deg. head leakage radiation of medical linear ...

First, models (room models) published in the international literature allowing the exposure to gamma radiation indoors due to building materials to be assessed are reviewed and discussed. For one of them, a sensitivity analysis concerning the effect of changing the parameters (e.g. dimensions of the room, thickness and density of the walls, etc.) used in ...

The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit w...

For several decades, accelerators designed primarily for research in nuclear and high energy physics have been adapted for biomedical research including radiotherapeutic treatment of human diseases such as pituitary disorders, cancer, and more recently, arteriovascular malformations. The particles used in these treatments include pions, protons and heavier ions such as carbon, ...

This study involves the measurement of photoneutron contamination emitted from a Siemens Primus medical linear accelerator by using BD-PND bubble detectors. Various bubble detectors were arranged around the linac head with the interval of I m and at the same height as the isocenter to measure the dose equivalent distribution in the treatment ...

Radon, radioactive natural gas resulting from the disintegration of Uranium and Thorium, is present in subsoil water as well as the air and building materials. Though it is present at weak concentrations, its inhalation increases to the exposure of the man to the radiation. The radon concentration varies with space, climatic conditions, etc... This paper focuses on modelling effect of the ...

In view of low cost, hydrogenous materials such as Polyethylene and CH2 have been developed and being used currently by NASA as an effective galactic cosmic radiation shields in place of aluminum for hull design of spacecraft. Lead, steel and concrete which are currently being used as effective radiation shields for the treatment of rooms equipped with Electron ...

Microstructural modification in hydroxypropyl methylcellulose (HPMC) polymer films induced by electron irradiation is studied. Irradiation was performed in air at room temperature using a 8 MeV electron accelerator at doses of 25, 50, 75 and 100 kGy. Irradiation can be used to crosslink or degrade the desired component or to fix the ...

A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic ...

A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic ...

A survey of a CLINAC 2100 C medical accelerator showed residual short half-life radiation after switching off the accelerator. This led to a dose of radiation for the medical employees when the patient was handled. The dose rate was measured with a dose rate meter FH40G, and annual ...

The logical development of an optimum design for a treatment room to contain a 4 Mev linear accelerator is presented. Although the design was developed around a particular machine (the A.E.I. Orthotron), it is basically applicable to other comparable megavoltage x-ray units intended for treating large numbers of patients. Topics considered ...

Adjoint Monte Carlo calculations have been made to determine the neutron and secondary-gamma doses along the vertical center line of a one-room concrete structure with and without windows. The doses are given as a function of geometric origin within the s...

A model has been developed to calculate the radiation dose incurred from natural radioactivity indoors and outdoors, expressed in effective dose equivalence/year. The model is applied on a three rooms dwelling characterized by interconnecting air flows an...

A radiation biology experiment was performed in the research room of the proton therapy facility at Loma Linda University Medical Center to simulate the proton exposure produced by a solar particle event. The experiment used two scanning magnets for X and Y deflection of the proton beam and covered a usable target area of nearly 1 m2. The magnet scanning control system ...

... Title : In-Situ Measurement of Total Dose Radiation Effects on Parallel Plate MOS Capacitors Using the NPS Linear Accelerator. ...

Intraoperative radiation therapy is a special radiotherapy technique, which enables a high dose of radiation to be given in a single fraction during oncological surgery. The major stumbling block to the large-scale application of the technique is the transfer of the patient, with an open wound, from the operating room to the radiation therapy bunker, with ...

alpha -SiC crystals were implanted with aluminum to a high dose at room temperature or 800 C. Transmission electron microscopy showed that SiC was amorphized by room temperature implantation but remained crystalline after 800 C implantation. Crystalline aluminum carbide was formed and aluminum redistribution took place in SiC implanted ...

made. A study of the characteristics of these plastic dose meters (in particular hexakis (hydroxy ethyl

... warfare, joint planning, national and international ... Corporate Author : ARMY NATICK LABS MASS. ... and dose distribution; Accelerators for food ...

The FDA recently approved irradiation treatment of leafy greens such as spinach up to 1 kGy; however, it is important to reduce the dose required to decontaminate the produce while maintaining its quality. Thus, the objectives of this study were: (1) to assess the radiation sensitivities of Salmonella spp. and Listeria spp. inoculated in ready-to-eat baby spinach leaves under ...

In this work, the ambient dose equivalent, H*(10), due to neutrons outside three bunkers that house a 15- and a 18-MV Varian Clinac 2100C/D and a 15-MV Elekta Inor clinical linacs, has been calculated. The Monte Carlo code MCNPX (v. 2.5) has been used to simulate the neutron production and transport. The complete geometries including linacs and full installations have been ...

Air has been irradiated with high energy protons at the 12 GeV proton synchrotron to obtain the following parameters essential for the internal dose evaluation from airborne 11C produced through nuclear spallation reactions: the abundance of gaseous and particulate 11C, chemical forms, and particle size distribution. It was found that more than 98% of 11C is present as gas and ...

Air has been irradiated with high energy protons at the 12 GeV proton synchrotron to obtain the following parameters essential for the internal dose evaluation from airborne /sup 11/C produced through nuclear spallation reactions: the abundance of gaseous and particulate /sup 11/C, chemical forms, and particle size distribution. It was found that more than 98% of /sup 11/C is ...

Stereotactic radiosurgery and image-guided radiotherapy (IGRT) place enhanced demands on treatment delivery machines. In this study, we describe a high-dose-rate output accelerator as a part of our stereotactic IGRT delivery system. The linac is a Siemens Oncor without a flattening filter, and enables dose rates to reach 1000 monitor ...

The discussion is confined to high gradient, room-temperature accelerators which have clean well-finished cavity surfaces and good vacuum conditions. Breakdown-initiating mechanisms due to ''cold'' field electron emission occurring at isolated sites on broad-area cavity surfaces, where the field is enhanced, are ...

The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. Measured data obtained at a variety of accelerator install...

The Stanford Linear Accelerator Center (SLAC) operates a high energy electron accelerator (capable of energies up to 50 GeV). During operation the instantaneous dose rates in the vicinity of the beam pipe due to beam losses can be extremely high. This res...

The effect of the Finnish sauna on insulin absorption from a subcutaneous injection site was examined in eight insulin-dependent diabetic patients by measuring externally the disappearance rate of 125I-labelled rapid-acting insulin. The sauna (twice for 25 minutes at 85 degrees C) accelerated insulin absorption by 110% as compared with room temperature (p ...

When radiotherapy with photon energies greater than 10 MV is performed neutrons contaminate the photon beam. In this paper the neutron contamination of the 15 MV photon mode of the Siemens Primus accelerator was studied. The Monte Carlo code MCNPX was used for the description of the treatment head and treatment room. The Monte Carlo results were verified ...

Beam scanning in proton therapy is a medical technique to lower the dose to healthy tissue while irradiating a tumor volume. Scanned proton beams for proton radiation therapy require small beam sizes at the tumor location. In beam scanning, a small beam usually less than 1 cm diameter is swept across the tumor volume with two magnets located several meters upstream of the ...

Beam scanning in proton therapy is a medical technique to lower the dose to healthy tissue while irradiating a tumor volume. Scanned proton beams for proton radiation therapy require small beam sizes at the tumor location. In beam scanning, a small beam usually less than 1 cm diameter is swept across the tumor volume with two magnets located several meters upstream of the ...

We describe the dosimetric characteristics of a newly introduced dual photon energy linear accelerator, the Varian Clinac 1800. Depth doses are compared with other accelerators of the same nominal accelerating potentials (6 and 10 MV). Field flatness at d/sub max/ and at 10 cm depth, depth of d/sub max/, wedge ...

... efforts were in facility start-up. ... was transported into Experimental Room 2 ... POWER SUPPLIES, PARTICLE ACCELERATOR COMPONENTS, DATA ...

The accelerator requirements of particle radiation therapy are reviewed and a preliminary design of a heavy ion synchrotron for hospital installation is presented. Beam delivery systems and multi-treatment room arrangements are outlined.

Antimotion sickness drugs tested in slow rotation room with controled Coriolis accelerations, noting

At one end of one of these rooms a fire was produced in a stack of mattresses soaked with an accelerant solvent to simulate an arson fire. ...

of $130 �C to room temperature. The neutron detector was a 5 in. � 3 in. Eljen Technology EJ-301 liquid

Typical camera designs include optical glass elements that may be affected by the ionizing radiation present in the natural space environment. Ordinary optical glasses darken at low (10(to the 3rd power) rad) dose levels when exposed to ionizing radiation. This darkening decreases the sensitivity of optical sensors. Optical glass flats of FK 51, LaK 0, PK 51A, and ZK Ny were ...

The radiation-induced development of spinodal-like compositional fluctuations in Fe-Ni-Cr invar alloys leads to several fortuitous methods of visualizing the three-dimensional nature of the decomposition process. In low dose neutron-irradiated Fe-Ni-Cr specimens, the use of high electropolishing rates during preparation of microscopy foils leads to a preferential attack of ...

The production of photoneutrons by electron accelerators is an unavoidable process at operating energies above about 10 MeV. These photoneutrons create problems in shielding, personnel protection, and induced radioactivity. This paper attempts to describe...

The on-line control system for dosimetric monitoring of the ''F'' installation is described. The system is designed for continuous measurements of the radiation in the accelerator rooms and for automatic alarm control of the accelerator operation and beam...

The normal state resistivity of the superconducting NbTi cable used in accelerator magnets is usually specified by the resistance per unit length at room temperature (295 K) and the residual resistance ratio (RRR). Using these resistance parameters, the a...

This article describes a high-charge-state linear post accelerator for enhancing the number and intensities of short-lived radioactive nuclei at the Holifield Radioactive Ion Beam facility (HRIBF). The system consists of a room temperature RFQ, a normal c...

This paper describes methods for extracting and absorbing unwanted higher-order modes (HOMs) from normal-conducting accelerator structures. An introduction to the problems caused by HOMs is followed by a brief history of the development of techniques to s...

A tungsten moderator will be placed behind the target of the Oak Ridge Electron Linear Accelerator (ORELA) to convert gamma radiation to slow positrons. These will be extracted and led through evacuated solenoids to an experiment room. A Penning trap will...

The CEBAF accelerator is designed in a multipass racetrack configuration, with two 1497 MHz linear accelerator sections joined by independent magnetic transport arcs. Room temperature subharmonic rf separator cavities will be used on each independent arc ...

Long range wakefields are a serious concern for a future linear collider based on room temperature accelerating structures. They can be suppressed either by detuning and or local damping or with some combination of both strategies. Detuning relies on prec...

A methodology for accelerated curing of commercially available room- temperature curing paste adhesives is outlined. Cure kinetics of the adhesive were studied by thermochemical analysis, and degree of cure was related to processing parameters and cure cy...

Within the past few years, interest in proton therapy has significantly increased. This interest has been generated by a number of factors including: 1) the reporting of positive clinical results using proton beams; 2) approval of reimbursement for delivery of proton therapy; 3) the success of hospital-based proton therapy centers; and 4) the availability of modern, integrated proton therapy ...

Within the past few years, interest in proton therapy has significantly increased. This interest has been generated by a number of factors including: 1) the reporting of positive clinical results using proton beams; 2) approval of reimbursement for delivery of proton therapy; 3) the success of hospital-based proton therapy centers; and 4) the availability of modern, integrated proton therapy ...

The effective doses and attenuation lengths for concrete and iron were measured for the design of heavy ion facilities. Neutrons were produced through the reaction of copper, carbon, and lead bombarded by carbon ions at 230 and 400 MeV.A, neon ions at 400 and 600 MeV.A, and silicon ions at 600 and 800 MeV.A. The detectors used were a Linus and a Andersson-Braun-type rem ...

Dose profiles throughout the front-end building and the accelerator tunnel were calculated for the SNS linac system both for normal operation and after shut down of the facility based on normal operations beam losses. The calculated dose levels at a cylin...

Operating nuclear plants in this country are bound by the Code of Federal Regulations (CFR). One of the requirements is to maintain the postaccident doses to control room personnel below the 10 CFR 50, Appendix A, General Design Criteria 19 (GDC-19) limits. These limits are 30-rem thyroid dose and 5-rem whole-body ...

In our previous paper which we presented here two years ago, we described the ALF (Advanced Lithography Facility), IBM's new facility for X-ray lithography which was built as an addition to the Advanced Semiconductor Technology Center at IBM's semiconductor plant in Hopewell Jct., NY. At that time, we described the structure, its utilities, facilities and special features such as the radiation ...

This thesis describes a study of shielding design techniques used for radiation therapy facilities that employ megavoltage linear accelerators. Specifically, an evaluation of the shielding design formalism described in NCRP report 151 was undertaken and a feasibility study for open-door 6 MV radiation therapy treatments in existing 6 MV, 18 MV treatment ...

This paper describes methods for extracting and absorbing unwanted higher-order modes (HOMs) from normal-conducting accelerator structures. An introduction to the problems caused by HOMs is followed by a brief history of the development of techniques to suppress them, and some examples taken from existing and planned accelerators. These include damped ...

As a training tool, Accelerated Learning techniques have been in use since 1956. Trainers from a variety of applications and disciplines have found success in using Accelerated Learning approaches, such as training aids, positive affirmations, memory aids, room arrangement, color patterns, and music. Some have thought that maintenance ...

An analysis is made of the permissible doses and protective measures for medical personnel working in radiology. (R.V.J.)

... day. The remaining 2 h were used to clean the rooms as well as to replace bedding and to ... ...

... Pagination or Media Count : 67. ... Data have been obtained for high-dose selenium implants carried out at room temperature and annealed at 850 C ...

... did not have a prospectively defined control arm. ... dose studied in the randomized, placebo-controlled trial was ... FDA White Oak Campus, the Great Room, White Oak ...

Effectiveness of antimotion sickness drugs compared by using recommended and larger than recommended

room:-y-re-seer. A radiation evaluation was -performed on -4:449 to determine the total dose tolerance of these parts. A hrief summary of the test ...

Fiber-coupled organic plastic scintillators enable on-line dose rate monitoring in conjunction with pulsed radiation sources like linear medical accelerators (linacs). The accelerator, however, generates a significant amount of stray ionizing radiation. This radiation excites the long optical fiber (15-20 m), connecting the ...

Background: For patients with sarcomas, radiotherapy can be used as neoadjuvant, adjuvant, or primary local therapy, depending on the site and type of sarcoma, the surgical approach, and the efficacy of chemotherapy. Methods: The authors review the current status of advanced technology radiation therapy in the management of bone and soft tissue sarcoma. Results: Advances in radiotherapy have ...

Spectroscopic and chromatographic methods (HPLC, HPLC-MS, NMR) were used to observe, separate and identify products of radiolysis of thiamphenicol (TF), irradiated in the solid state at room temperature and atmospheric pressure with an electron beam from a linear accelerator to doses between 25 and 800 kGy. Nine products of radiolysis ...

The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and ...

The accurate determination of personal dose equivalent requires the proper use of appropriate radiological quantities and units, knowledge of the dose equivalent response of the personal dosemeters used and detailed information on the fluence as well as dose equivalent spectra at the workplaces. This information can then be used to ...

Central axis depth absorbed dose distributions of the electron beam from a medical microtron accelerator have been measured. The measured distributions differ from those of existing betatrons and linear accelerators. A larger absorbed dose build-up and a sharper dose fall-off are obtained in ...

Relative dose distribution data have been given for 8 sectors around the isocentre of a Philips telecobalt unit that is applied at the Radiologische Klinik of the Medizinische Akademie Erfurt. (Atomindex citation 15:072723)

Two commercial acetal resins (Delrin and Celcon) were exposed to reactor radiation at room temperature in air to five levels of absorbed dose. The tensile strength of both resins was found to decrease rapidly with increasing dose: 50% of the original valu...

The RADionuclide Transport, Removal, And Dose (RADTRAD) code is designed for US Nuclear Regulatory Commission (USNRC) use to calculate the radiological consequences to the offsite population and to control room operators following a design-basis accident ...

surgeons, operating room staff) must be Monitored using personal dosimeters and/or dose rate meters to track radiation dose in real time Minimized by rotating staff to...

A straightforward method for estimating the contribution of scattered neutrons to total flux or radiation dose is described. The method is based on results obtained by measuring the fluxes and spectra of neutrons emitted by a Pu-Be source and scattered in...

The effect of different doses of {gamma}-irradiation on the conductivity of PVdF-LiPF{sub 6} solid polymer electrolyte (SPE) was investigated at room temperature. The dielectric constant and loss are seen to increase with increasing radiation doses.

The effect of different doses of ?-irradiation on the conductivity of PVdF-LiPF6 solid polymer electrolyte (SPE) was investigated at room temperature. The dielectric constant and loss are seen to increase with increasing radiation doses.

Properties of several room-temperature cavities for standing-wave linear accelerator structures are discussed. In particular, new results related to the disk-and-washer geometry are presented. Extensive calculations using the computer program SUPERFISH have shown that the ..beta.. = 1.0 the effective shunt impedance is at least 20% higher than that of an ...

The irradiation facility or the Radiation Center of Osaka Prefecture (ORC) was built for the purpose of the studies and service of irradiation. This building contained an electron linear accelerator and a Co-60 source of 4810 curies. The Linac was to have 15 Mev energy and 8 kw power. This building had three independent foundations, for the Linac ...

A new Main Control Room (MCR) has been built to control the accelerators of the AGS Complex. A new physical environment was produced to better control light, sound, temperature, and traffic. New control consoles were built around the work-stations that make up the distributed control system. Equipment placement within consoles and console placement within ...

The development of a computational model for the treatment head of a medical electron accelerator (Elekta/Philips SL-18) by the Monte Carlo code mcnp-4C2 is discussed. The model includes the major components of the accelerator head and a pmma phantom representing the patient body. Calculations were performed for a 14 MeV electron beam impinging on the ...

For several years, research has been ongoing in the Ohio State University (OSU) Nuclear Engineering Program toward the development of an accelerator-based irradiation facility (ANIF) neutron source for boron neutron capture therapy (BNCT). The ANIF, which is planned to be built in a hospital, has been conceptually designed and analyzed. After Qu, an OSU researcher, determined ...

threshold of 0.0839, and d the differ- ence of the de-noised and low-noise dose distributions. The dose 336 floating point arithmetic operations per dose grid point. We applied wavelet threshold de of producing clini- cally usable dose distributions, i.e., with low enough noise, with much shorter calculation

We report on the first irradiation of in vitro tumour cells with laser-accelerated proton pulses showing dose-dependent biological damage. This experiment, paving the way for future radiobiological studies with laser-accelerated protons, demonstrates the simultaneous availability of all the components indispensable for systematic ...

Fifty-six sites in 49 patients were irradiated by a 7 day-week accelerated fractionation schedule to conventional tumor doses. Daily doses were 180 to 200 rad in 85% of sites. Patients were analyzed for normal tissue tolerance. A 7 day/week accelerated fractionation appears clinically tolerable at 180 rad per ...

A nationwide survey was conducted on electron accelerators for radiation therapy in Japan for obtaining fundamental data on the actual operational situation of these accelerators. The research subjects were all medical institutions equipped with electron accelerators for radiation therapy (874 accelerators) in ...

This chapter is designed to serve as a review and reference for the wide and still-evolving field of particle sources and accelerators. The object of this chapter is to give a comprehensive and easily understandable survey of the field in greater detail to the users of accelerators, nuclear physicists and chemists, as well as students. The field of ...

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 ...

Radiosurgery techniques permit high doses of single fraction irradiation to be administered to small volumes of tumor with relative sparing of surrounding brain tissue. The tolerance of surrounding normal brain tissue to dose distributions from linear accelerator radiosurgery with different collimator sizes is an important factor that ...

Purpose: The aim of this study was to compare the dosimetric consequences of 4 treatment delivery techniques for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: During an 8-week course of radiotherapy, 10 patients underwent computed tomography (CT) scans 3 times per week (243 total) before daily treatment with a CT-linear ...

The technologies with kilovoltage (kV) and megavoltage (MV) imaging in the treatment room are now available for image-guided radiation therapy to improve patient setup and target localization accuracy. However, development of strategies to efficiently and effectively implement these technologies for patient treatment remains challenging. This study proposed an aggregated ...

The technologies with kilovoltage (kV) and megavoltage (MV) imaging in the treatment room are now available for image-guided radiation therapy to improve patient setup and target localization accuracy. However, development of strategies to efficiently and effectively implement these technologies for patient treatment remains challenging. This study proposed an aggregated ...

This book contains 16 selections. Some of the titles are: Some Changes in Dose Fractionation over 20 Years; Time, Dose and Fractionation in Radiation Therapy: An Historical Perspective; Twice-Daily Radiation Therapy for Head and Neck Carcinomas; Accelerated Repopulation in Head and Neck Cancer; and Accelerated ...

A real-time measurement system of the spatial dose distribution is developed and realized for monitoring the bremsstrahlung flow generated on X-ray target by 5MeV 50kW electron accelerator. The sensors of the system consist of semiconductor diodes. The beam target and electron accelerator (ILU-10) are briefly described. The practice of ...

Fetal exposure to high doses of glucocorticoids slows cellular development and impairs organ performance, in association with growth retardation. evertheless, low doses of glucocorticoids may enhance cell differentiation and accelerate specific functions. he current study examine...

A simple calorimetric dosimeter has been contrived to measure the radiation dose absorbed by di(2-ethylhexyl)phosphoric acid in irradiation with an electron or photon beam from a 60 MeV electron accelerator. The absorbed dose rate is related to the beam c...

Basic formulae governing thermal flow in water-cooled solids are given. By calculating the heat dissipation at room temperature of the LEP accelerating cell with the program SUPERFISH and then using this as input to the thermal analysis program DOT, the surface temperatures and losses at full power have been estimated. Good agreement is obtained when these ...

This work reports on the characterisation of a neutron beam shaping assembly (BSA) prototype and on the preliminary modelling of a treatment room for BNCT within the framework of a research programme for the development and construction of an accelerator-based BNCT irradiation facility in Buenos Aires, Argentina. The BSA prototype constructed has been ...

Monte Carlo simulation was used to calculate the lateral buildup ratio (LBR) used in estimating the percentage depth dose (PDD) and dose per monitor unit for an irregular shaped cutout field in electron radiotherapy. Monte Carlo code BEAMnrc/EGSnrc was used to build a simulation model for a Varian 21 EX linear accelerator producing ...

Neutron irradiations with low ..gamma..-ray flux in the Intense Pulsed Neutron Source were carried out on four kinds of cloth-filled organic composites (filler: E-glass or carbon fiber; matrix: epoxy or polyimide resin) and a unidirectional alumina fiber/epoxy composite. The mechanical test was performed at room temperature. Following irradiation at room ...

The use of intensity modulated radiation therapy promises to spare organs at risk by applying better dose distribution on the tumor. The specific challenge of this methods is the exact positioning of the patient and the localization of the exposured organ. With respect to the filling of rectum and bladder the prostate can move several millimeters up to centimeters. Therefore, ...

An independent assessment of the dose delivery in ion therapy can be performed using positron emission tomography (PET). For that a distribution of positron emitters which appear as the result of interaction between ions of the therapeutic beam and the irradiated tissue is measured during or after the irradiation. Three concepts for PET monitoring implemented in various ...

An independent assessment of the dose delivery in ion therapy can be performed using positron emission tomography (PET). For that a distribution of positron emitters which appear as the result of interaction between ions of the therapeutic beam and the irradiated tissue is measured during or after the irradiation. Three concepts for PET monitoring implemented in various ...

Damage nucleation in single crystals of silicon during ion irradiation is investigated. Experimental results and mechanisms for damage nucleation during both room and liquid nitrogen temperature irradiation with different mass ions are discussed. It is shown that the accumulation of damage during room temperature irradiation depends on the rate of ...