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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.
The scanning helium microscope (SHeM) is a form of microscopy that uses low-energy (5–100 meV) neutral helium atoms to image the surface of a sample without any damage to the sample caused by the imaging process. Since helium is inert and neutral, it can be used to study delicate and insulating surfaces.
As the helium ion beam interacts with the sample, it does not suffer from a large excitation volume, and hence provides sharp images with a large depth of field on a wide range of materials. Compared to a SEM, the secondary electron yield is quite high, allowing for imaging with currents as low as 1 femtoamp. The detectors provide information ...
Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen. Rockets need to achieve specific speeds and ...
IMS instruments are extremely sensitive stand-alone devices, but are often coupled with mass spectrometry, gas chromatography or high-performance liquid chromatography in order to achieve a multi-dimensional separation. They come in various sizes, ranging from a few millimetres to several metres depending on the specific application, and are ...
Helium is the least water-soluble monatomic gas, [96] and one of the least water-soluble of any gas (CF 4, SF 6, and C 4 F 8 have lower mole fraction solubilities: 0.3802, 0.4394, and 0.2372 x 2 /10 −5, respectively, versus helium's 0.70797 x 2 /10 −5), [97] and helium's index of refraction is closer to unity than that of any other gas. [98]
A disgraced Missouri teacher is scheduled to enter pleas next month to 19 charges alleging she paid her underage students for sex with cash, alcohol and marijuana and then attempted to intimidate ...
Sydney Sweeney hit back after body shamers piled on one of her Instagram posts, which included videos and photos of her hitting the gym to prepare for her role as boxer Christy Martin.