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A radionuclide identification device (RID or RIID) is a small, lightweight, portable gamma-ray spectrometer used for the detection and identification of radioactive substances. [1]
The Bühlmann decompression model is a neo-Haldanian model which uses Haldane's or Schreiner's formula for inert gas uptake, a linear expression for tolerated inert gas pressure coupled with a simple parameterised expression for alveolar inert gas pressure and expressions for combining Nitrogen and Helium parameters to model the way inert gases enter and leave the human body as the ambient ...
Though all heavier helium isotopes decay with a half-life of <1 second, particle accelerator collisions have been used, to create unusual nuclei of elements such as helium, lithium, and nitrogen. The unusual nuclear structures of such isotopes may offer insights into the isolated properties of neutrons and physics beyond the Standard Model .
A gas pycnometer is a laboratory device used for measuring the density—or, more accurately, the volume—of solids, be they regularly shaped, porous or non-porous, monolithic, powdered, granular or in some way comminuted, employing some method of gas displacement and the volume:pressure relationship known as Boyle's law.
An HID connected to a gas chromatograph (GC) has the great advantage to use helium as both the carrier gas and the ionization gas. An HID is an ion detector which uses a radioactive source, typically β-emitters, to create metastable helium species. [1] The radioactive source ionizes helium atoms by bombarding them with emissions.
Computing the total disintegration energy given by the equation = (), where m i is the initial mass of the nucleus, m f is the mass of the nucleus after particle emission, and m p is the mass of the emitted (alpha-)particle, one finds that in certain cases it is positive and so alpha particle emission is possible, whereas other decay modes ...
Helium is used as a tracer because it penetrates small leaks rapidly. Helium also has the properties of being non-toxic, chemically inert and present in the atmosphere only in minute quantities (5 ppm). Typically a helium leak detector will be used to measure leaks in the range of 10 −5 to 10 −12 Pa·m 3 ·s −1.
Eluants from the GC column, flowing counter to the flow of helium from the discharge zone, are ionized by photons from the helium discharge. Bias electrode(s) focus the resulting electrons toward the collector electrode , where they cause changes in the standing current which are quantified as the detector output.