Mass spectrometry has been regarded as one of the most valuable analytical instruments since any compound has its intrinsic mass value. However, mass spectrometry can only be used to measure the mass-tocharge ratio (m/z) of a charged particle. Therefore, ionization process is usually needed unless the particle to be measured has an intrinsic charge. Nevertheless, the ionization efficiency is us...

introduction: well type ionization chamber is a measuring device which is used to determine the activity of brachytherapy sources. the chamber has a cylindrical volume in which a cylindrical tube is mounted in the middle of the chamber. for the measurements, the brachytherapy sources are transferred to the middle of the tube. materials and methods: for designing the well type chamber, the measu...

Introduction: Microdosimetry is a fundamental method that studies the nature of energy transfer in micron volumes in the particular biological cells. In a biological target, the amount of ionization does not indicate the magnitude of biological radiation-induced damage. However, the severity of biological harm depends strongly on the amount of the linear energy transfer along t...

Introduction: Radiation therapy is using the ionizing radiation to eliminate or minimize cancerous tissues. This method has been very much considered in recent years. Because of the high energy of the photons produced by the accelerator, it is necessary to protect the walls, roof and the floor of the treatment rooms using the concrete and leaden materials. One of these harmful ...

The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the ab...

The charge loss due to initial recombination was measured for various therapy level ionization chamber types. Different methods were applied. Measurements were performed in Co beams, pulsed high-energy photon beams and pulsed high-energy electron beams. The results are mutually consistent within less than 0.05 %. Within this uncertainty initial recombination and diffusion do not depend on the r...

The uncertainty of the beam quality conversion factor (k(Q,Q0)) of standard dosimetry of absorbed dose to water in external beam radiotherapy 12 (JSMP12) is determined by combining the uncertainty of each beam quality conversion factor calculated for each type of ionization chamber. However, there is no guarantee that ionization chambers of the same type have the same structure and thickness, s...

background: the monte carlo method is the most accurate method for simulation of radiation therapy equipment. the linear accelerators are currently the most widely used machines in radiation therapy centers. methods: in this work, a monte carlo modelling of the siemens oncor linear accelerator in 6 mv and 18 mv beams was performed. the results of simulation were validated by measurements in wat...

The front IR quadrupole absorbers (TAS) and the IR neutral particle absorbers (TAN) in the high luminosity insertions of the Large Hadron Collider (LHC) each absorb approximately 1.8 TeV of forward collision products on average per pp interaction (~235W at design luminosity 10cms). This secondary particle flux can be exploited to provide a useful storage ring operations tool for optimization of...