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An ion drift meter is a device used to measure the velocity of individual ions in the area of a spacecraft. This information can then be used to calculate the ion drift in the space surrounding the instrument as well as the strength of an electric field present, provided that the magnetic field strength has been determined using a magnetometer .
Drift tube ion mobility spectrometry (DTIMS) measures how long a given ion takes to traverse a given length in a uniform electric field through a given atmosphere. In specified intervals, a sample of the ions is let into the drift region; the gating mechanism is based on a charged electrode working in a similar way as the control grid in ...
Ion mobility spectrometry-mass spectrometry (IMS/MS or IMMS) is a technique where ions are first separated by drift time through some neutral gas under an applied electrical potential gradient before being introduced into a mass spectrometer. [43] Drift time is a measure of the collisional cross section relative to the charge of the ion.
SSIES, or the Special Sensors-Ions, Electrons, and Scintillation thermal plasma analysis package is a suite of instruments built by the William B. Hanson center for Space Sciences at the University of Texas at Dallas and flown on a number of the DMSP satellites.
For example, the mobility of the sodium ion (Na +) in water at 25 °C is 5.19 × 10 −8 m 2 /(V·s). [1] This means that a sodium ion in an electric field of 1 V/m would have an average drift velocity of 5.19 × 10 −8 m/s. Such values can be obtained from measurements of ionic conductivity in solution.
ICON was equipped with four instruments: a Michelson interferometer, built by the United States Naval Research Laboratory (NRL) to measure the winds and temperatures in the thermosphere; an ion drift meter, built by University of Texas at Dallas to measure the motion of charged particles in the ionosphere; and two ultraviolet imagers built at ...
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".
Drift tube ion mobility does not employ RF voltage which may heat ions, and it can preserve the structure of the ions. The rotationally averaged collision cross section (CCS) which is a physical property of ions reflecting the shape of the ions can be measured accurately on drift tube ion mobility. [ 11 ]