TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 CONT

Impact ionization and avalanche multiplication of electrons and holes in the presence of a large electric field. The excess energy is given off to generate an electron-hole pair through a band-to-band transition. This generation process causes avalanche multiplication in semiconductor diodes under high reverse bias : As one carrier accelerates in the electric field it gains energy. The kinetic energy is given off to an electron in the valence band, thereby creating an electron-hole pair. The resulting two electrons can create two more electrons which generate four more causing an avalanche multiplication effect. Electrons as well as holes contribute to avalanche multiplication.  1, record 1, English, - avalanche%20multiplication%20effect

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 DEF

Effet qui se manifeste par l'augmentation rapide des porteurs de charge lorsqu'un champ électrique intense agit sur un semi-conducteur.  1, record 1, French, - effet%20d%27avalanche

Record 1,  Textual support,  Spanish

Record 2,  Textual support,  English

Record number: 2, Textual support number: 1 DEF

Ionization resulting from the collision of a particle with a positively or negatively charged ion.  3, record 2, English, - chemical%20ionization

Record number: 2, Textual support number: 1 CONT

Mass spectrometry.... Methods of ion production. For analysis of organic compounds the principal methods are electron impact, chemical ionization, field ionization, and field desorption... Chemical ionization. Here the ions to be analysed are produced by transfer of a heavy particle... to the sample from ions produced from a reactant gas.  4, record 2, English, - chemical%20ionization

Record 2,  Textual support,  French

Record number: 2, Textual support number: 1 DEF

Ionisation résultant d'une collision d'une particule avec un ion chargé positivement ou négativement.  2, record 2, French, - ionisation%20chimique

Record number: 2, Textual support number: 1 CONT

Spectrométrie de masse [...] Ionisation chimique. Elle équipe pratiquement tous les appareils modernes destinés à l'analyse organique [...] L'ionisation, qui fait intervenir un gaz réactant, (le méthane par exemple,) s'effectue en plusieurs étapes : Ionisation par bombardement électronique du gaz réactant à pression élevée [...] Réactions ions-molécules du gaz réactant [...] Ionisation du composé organique [...] par transfert de protons [...], par transfert de chaînes alcoyles [...], par abstraction de H^- ou de chaînes alcoyles.  3, record 2, French, - ionisation%20chimique

Record 2,  Textual support,  Spanish

Record number: 2, Textual support number: 1 CONT

En la ionización química los átomos gaseosos de la muestra (tanto de un sistema de entrada indirecto como de una sonda caliente) se ionizan al colisionar con los iones producidos al bombardear con electrones un exceso de gas reactivo (normalmente metano). Normalmente se utilizan iones negativos [...]  2, record 2, Spanish, - ionizaci%C3%B3n%20qu%C3%ADmica

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 CONT

Thermionic or Electron Impact Detector. In 1957, Ryce and Bryce described a sensitive ionization gauge based on the ionization potentials of vapors. It comprised a filament, a grid, and a plate. The potential difference between the filament and grid accelerated electrons which may ionize any gas in their path. If the grid potential is maintained at a level insufficient to ionize the helium carrier gas... no current flows in the plate circuit. If a potential difference of 18 V is maintained between the filament and the grid, compounds of lower ionization potential in the helium will be ionized and the positive ions produced will yield a cathode current, the current noted being a measure of the ion concentration. Into the modified ionizing chamber, operated at reduced pressure, a small fraction of the column effluent gas stream(less than 0. 5%) was allowed to flow into the gauge through a controlled leak. Over a 0. 02-l. 5 mm Hg pressure range, the sensitivity was approximately proportional to the pressure, and sensitivities in the range of 10[ minus superscript 12] mole were claimed.  1, record 3, English, - electron%20impact%20detector

Record 3,  Textual support,  French

Record 3,  Textual support,  Spanish

Record 4,  Textual support,  English

Record number: 4, Textual support number: 1 OBS

... ion sources fall into three major categories :... for positive-ion generation,... for negative ion generation, and a highly specialized type of source designed to produce a polarized ion beam.... The principal methods of positive-ion formation are electron impact, surface ionization, spark discharge... [in this Patter technique] a spark is induced between two electrodes, one of which, at least, contains the element to be ionized... the spark consists of a high density, high-temperature plasma from which ions can be extracted.  2, record 4, English, - spark%20source

Record 4,  Textual support,  French

Record number: 4, Textual support number: 1 CONT

L'ionisation par étincelles est utilisée pour l'analyse élémentaire des solides minéraux conducteurs de l'électricité ou rendus tels. Avec le matériau dont on veut connaître la composition, on réalise [...] deux électrodes [...] reliées, sous vide, aux bornes d'un générateur haute fréquence [...] et haute tension [...] Lorsque la distance inter-électrodes [...] diminue, des claquages apparaissent; ils produisent [...] un grand nombre d'ions mono et polychargés [...] Ces ions sont accélérés et dirigés vers un spectromètre; [...]  1, record 4, French, - source%20%C3%A0%20ionisation%20par%20%C3%A9tincelles

Record 4,  Textual support,  Spanish

Record 5,  Textual support,  English

Record number: 5, Textual support number: 1 CONT

The principal methods of positive-ion formation are electron impact, surface ionization, spark discharge.... Surface ionization. Atoms possessing low ionization potentials can be ionized by allowing them to strike a heated surface having a high work function... the atom will be thermally desorbed as a positive ion.  1, record 5, English, - surface%20ionization

Record 5,  Textual support,  French

Record number: 5, Textual support number: 1 CONT

Source à ionisation de surface (ou thermo-ionisation) (...) On dirige sous vide, vers une surface métallique chauffée (...) la vapeur atomique d'un élément (...) La faible dispersion énergétique des ions produits (...) permet leur analyse par un simple lecteur magnétique.  1, record 5, French, - ionisation%20de%20surface

Record number: 5, Textual support number: 1 OBS

Ce procédé fournit des courants d'ions intenses (...) et stables pour tous les éléments de faible potentiel d'ionisation (alcalins, ternes, rares, etc.).  1, record 5, French, - ionisation%20de%20surface

Record 5,  Textual support,  Spanish

Record 6,  Textual support,  English

Record number: 6, Textual support number: 1 CONT

Methods of ion production. For analysis of organic compounds the principal methods are electron impact, chemical ionization, field ionization and field desorption. Electron impact. When a gaseous sample of a molecular compound is ionized with a beam of energetic... electrons, part of the energy is transferred to the ion formed by the collision....  1, record 6, English, - electron%20impact

Record number: 6, Textual support number: 1 OBS

Examples of ion sources utilizing this concept are the duoplasmatron and the Penning ion source.  1, record 6, English, - electron%20impact

Record 6,  Textual support,  French

Record number: 6, Textual support number: 1 OBS

Ionisation par bombardement électronique (...) L'échantillon, en phase vapeur et sous faible pression (...) est bombardé par un faisceau d'électrons (...) émis par un filament de tungstène ou de rhénium (...) La plus grande partie des ions formés sont chargés positivement (...) La notation M[exposant]+. signifie que l'on obtient un ion moléculaire radicalaire (...) à partir de la molécule M.  1, record 6, French, - bombardement%20%C3%A9lectronique

Record 6,  Textual support,  Spanish