a time-of-flight mass spectrometer (tof-ms) developed in our laboratory at isfahan university of technology is described here. the tof-ms instrument uses laser as the ionization source which provides an opportunity to investigate the ions formed in laser ablation or desorption. the tof-ms has an ionization chamber containing an accelerator and an ion lens to focus the ions into a one meter line...

The ionization chambers are widely utilized in diagnostic radiology quality control and dosimetry. They are simple to use, and can be found commercially in various types depending on their applications. They are the recommended devices for the determination of the beam qualities in mammographic range. To assure the reliability of the measurements, the stability of the response of the ionization...

A method for calibrating iodine-125 seeds in terms of exposure has been established. The standard free-air ionization chamber, used for measuring soft x rays, was chosen for the measurements. Arrays of four to six seeds were used to enhance the ionization-current-to-background-current ratio. Seeds from an array were measured individually in a re-entrant chamber. The quotient of the exposure rat...

The recalculation of 1 fraction from a patient treatment plan on a phantom and subsequent measurements have become the norms for measurement-based verification, which combines the quality assurance recommendations that deal with the treatment planning system and the beam delivery system. This type of evaluation has prompted attention to measurement equipment and techniques. Ionization chambers ...

Background: The aim of this work was to study the output factors for Linac using different ionization chambers and build up caps. Materials and Methods: Output factors were measured for open square fields (3 × 3 cm to 40 × 40 cm) defined by collimator jaws for 6 and 15 MV photon beams from a Varian Clinac 2100C accelerator were measured. The measurements in air were performed using Com...

introduction hadron-therapy is an effective technique used to treat tumors that are located between or nearby vital organs. the italian national center of oncological hadron-therapy (cnao) has been realized as the first facility in italy to treat very difficult tumors with protons and carbon ions. the on-line monitor system for cnao has been developed by the department of physics of the univers...