The values of the replacement correction factors (P(repl), or in the IAEA's notation p(dis)p(cav)) used for cylindrical chambers in high-energy photon beams represent one of the most significant differences between the AAPM and the IAEA dosimetry protocols. In a previous study (Wang L L W and Rogers D W O 2008 Med. Phys. 35 1747-55), we found that the AAPM protocol adopted incorrect values of P...

[1] The construction of a large volcanic edifice at Earth’s surface generates stresses in the upper crust whose magnitude is comparable to those of tectonic stresses and overpressures within a magma chamber. We study how this affects eruption behavior. Analytical calculations are carried out in two dimensions for a cylindrical reservoir with an internal overpressure in an elastic half-space wit...

An integrated process which is proposed for improving dust removal efficiency of cyclones in another paper is considered here for simulation by Artifitial Neural Networks (ANNs) and hybrid ANN and Genetic Algorithm (GA). The process incorporates of two cyclones coupled with a specially designed cylindrical chamber, which includes a rotating tube inside it with air-impinging nozzles drilled on t...

Verification of the strength of high dose rate (HDR) (192)Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of ...

Delivery quality assurance (DQA) of tomotherapy plans is routinely performed with silver halide film which has a limited range due to the effects of saturation. DQA plans with dose values exceeding this limit require the dose of the entire plan to be scaled downward if film is used, to evaluate the dose distribution in two dimensions. The potential loss of fidelity between scaled and unscaled D...

The aim of the project is to build a small ion chamber serving as a prototype of a much larger dark matter detector to be built in the future. This is a brand-new project at Fermilab; my task would be to come up with the prototype ion chamber and a first set of measurements. To start with, the small chamber is going to be filled with Argon extracted from the air, i.e. predominantly 40Ar and tra...

Proven conventional dosimetry techniques do not provide accuracy and precision in the measurement of inverse planned intensity modulated radiation therapy (IMRT) fields. Dynamic and step-and-shoot multileaf collimation (DMLC/SMLC) challenge current ionization chamber dosimetry practices. Ionization chamber performance in these fields is evaluated for three cylindrical chambers of varying volume...

The Mark II experiment first started taking data in 1978 at the SLAC SPEAR storage ring. It was the first e+edetector with a large, many layer cylindrical drift chamber (CDC) and a large liquid argon calorimeter!” After two years at SPEAR, it was moved to the PEP storage ring, where it was upgraded a year later with a seven layer precision vertex drift chamber!’ located between the CDC and the ...

A crystal growth apparatus was designed and built to study the effect of growth modifiers, antifreeze proteins and antifreeze glycoproteins (AFGPs), on ice crystal growth kinetics and morphology. We used a capillary growth technique to obtain a single ice crystal with well-defined crystallographic orientation grown in AFGP solution. The basal plane was readily observed by rotation of the capill...

One of the important conclusions of our first E951 run is that, even at the reduced beam intensities that were reached, much of the mercury contained in the jet was dispersed at typical transverse velocities of the order of 10 m/s. We therefore must assume that, at full intensity, most of the mercury contained in a 30 m/s jet entering a 16 cm diameter, 80 cm long cylindrical magnet chamber will...