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The most common ion gauge is the hot-cathode Bayard–Alpert gauge, with a small collector inside the grid. [1] A glass envelope with an opening to the vacuum can surround the electrodes, but usually the nude gauge is inserted in the vacuum chamber directly, the pins being fed through a ceramic plate in the wall of the chamber.
The term ionometer was originally applied to a device for measuring the intensity of ionising radiation.Examples of radiation detectors described as ionometers can be found through to the 1950s but the term more often now means a device for measuring the chemical ion concentration of a fluid.
By far the most common US civil defense meter on the market today. This is a simple ion chamber radiological survey meter, specifically designed for high-radiation fields for which Geiger counters will give incorrect readings (see above). Survey meters do not read alpha or beta radiation.
Moisture is the main problem that affects the accuracy of ion chambers. The chamber's internal volume must be kept completely dry, and the vented type uses a desiccant to help with this. [ 2 ] Because of the very low currents generated, any stray leakage current must be kept to a minimum in order to preserve accuracy.
The ion current is generated by the creation of "ion pairs", consisting of an ion and an electron. The ions drift to the cathode while free electrons drift to the anode under the influence of the electric field. This current is independent of the applied voltage if the device is being operated in the "ion chamber region".
Total ionic strength adjustment buffer (TISAB) is a buffer solution which increases the ionic strength of a solution to a relatively high level. This is important for potentiometric measurements, including ion selective electrodes, because they measure the activity of the analyte rather than its concentration.
where t D is the ion drift time, Δt D is the Full width at half maximum, L is the tube length, E is the electric field strength, Q is the ion charge, k is the Boltzmann constant, and T is the drift gas temperature. Ambient pressure methods allow for higher resolving power and greater separation selectivity due to a higher rate of ion-molecule ...
In a photoionization detector, high-energy photons, typically in the vacuum ultraviolet (VUV) range, break molecules into positively charged ions. [2] As compounds enter the detector they are bombarded by high-energy UV photons and are ionized when they absorb the UV light, resulting in ejection of electrons and the formation of positively charged ions.