| well counter | A scintillation crystal shaped with a central hole to receive a small sample, plus associated detector and electronics. (05 Mar 2000) |
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| whole-body counter | Shielding and instrumentation, usually involving more than one detector, designed to evaluate the total-body burden of various gamma-emitting nuclides. (05 Mar 2000) |
| Coulter counter | <apparatus> Particle counter used for bacteria or eukaryotic cells, works by detecting change in electrical conductance of a small aperture as fluid containing cells is drawn through (the cell, a nonconducting particle, alters the effective cross-section of the conductive channel). (18 Nov 1997) |
| counter- | Opposite, opposed, against. See: contra-. Origin: L. Contra, against (05 Mar 2000) |
| proportional counter | A Geiger-Muller counter operating in the voltage range and under conditions in which pulse height is proportional to the energy of the particles or rays being counted, thus making discrimination between particles or rays of different energies possible. (05 Mar 2000) |
| scintillation counter | An instrument used for the detection of radioactivity; the radiation is absorbed by a scintillator (a crystal or a compound, such as POPOP, in solution) which results in minute flashes of light that are detected by a photocathode. The resultant electron emission is amplified by a photomultiplier and an amplifier. Synonym: scintillometer, spinthariscope. (05 Mar 2000) |
| drug, over-the-counter | Drug for which a prescription is not needed. (12 Dec 1998) |
| electronic cell counter | <apparatus, haematology> An automatic blood cell counter in which cells passing through an aperture alter resistance and are counted as voltage pulses, or in which cells passing through a flow cell deflect light. Some types of counter are capable of multiple simultaneous measurements on each blood sample; e.g., leukocyte count, red cell count, haemoglobin, haematocrit, and red cell indices. (21 Jun 2000) |