Inexpensive plasma discharge source for molecular emission spectroscopy with application to 15N analysis

Autor:	C. M. Preston, D. I. Hoult
Rok vydání:	1992
Předmět:	Materials science business.industry Transistor Impedance matching Plasma law.invention Photodiode Ignition system Nuclear magnetic resonance law Optoelectronics Electric discharge Emission spectrum business Instrumentation Glass tube
Zdroj:	Review of Scientific Instruments. 63:1927-1931
ISSN:	1089-7623 0034-6748
DOI:	10.1063/1.1143306
Popis:	The assaying of nitrogen isotope abundance using emission spectroscopy commonly requires a plasma discharge in a sample of N2 gas at low pressure (∼0.5 kPa) in a sealed glass tube. Expensive high‐power (≳20 W) radio‐frequency or microwave amplifiers are often used for this purpose. However, with correct design, a simple and inexpensive, single transistor, 100 MHz, 1 W oscillator can be used to produce a bright plasma discharge in a low‐pressure sample of nitrogen in a 6 mm diameter by 10 cm tube. The device utilizes optimal impedance matching to minimize the power requirements. The principles and limitations of the matching are outlined, and a simple feedback circuit is also described which, with the aid of a phototransistor, enables the emission intensity to be controlled. Ignition of discharge by friction or with the help of a simple piezoelectric gas lighter is also described, and construction details are given.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::a4eb5714eedab0faa7d981d19d2eb56b https://doi.org/10.1063/1.1143306 Zobrazit plný text záznamu