The ionization response of hydrocarbons In a hydrogen-atmosphere flame was compared to that of a normal flame ionization detector used in gas chromatography. Absolute response in the hydrogen-atmosphere flame lonizatlon detector (HAFID) was found to be two orders of magnitude less than that of the normal FID. This reduced response is attributed both to oxidation of hydrocarbons in the precombus...

Under the appropriate separation conditions the pulsed discharge helium ionization detector (PDHID) was used to detect hydrogen and methane separated from the matrix components of human breath samples. The sensitivity of this method is over an order of magnitude better than published methods using a flame ionization detector (FID) and a thermal conductivity detector (TCD), and has the further a...

Most modern radiation therapy devices allow the use of very small fields, either through beamlets in Intensity-Modulated Radiation Therapy (IMRT) or via stereotactic radiotherapy where positioning accuracy allows delivering very high doses per fraction in a small volume of the patient. Dosimetric measurements on medical accelerators are conventionally realized using air-filled ionization chambe...

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...

A measurement of ionization yields in noble-gas liquids is relevant to the energy calibration of nuclear recoil detectors for darkmatter search and coherent neutrino-nucleus scattering experiments. In this work we further study the ionization yield of nuclear recoils in liquid Ar, using a two-phase detector with an electroluminescence gap and DD neutron generator. The ionization yields of nucle...

Tunnel ionization belongs to the fundamental processes of atomic physics. The so-called two-step model, which describes the ionization as instantaneous tunneling at the electric field maximum and classical motion afterwards with zero exit momentum, is commonly employed to describe tunnel ionization in adiabatic regimes. In this contribution, we show by solving numerically the time-dependent Sch...

The suitability of a natural diamond detector with a special contact system for the measurement of relative dose distributions in selected radiotherapy applications was studied. The performance of the diamond detector was analysed by comparison with measurements using an ionization chamber and a silicon diode detector. The good stability, high response and good spatial resolution of the diamond...