Sensitivity improvement in NQR based detection methods

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Sensitivity improvement in NQR based detection methods

Popis výsledku v původním jazyce

This article presents an approach to sensitivity improvement in a detection method based on nuclear quadrupole resonance (NQR); this technique is widely applied in, for example, the detection of explosives. We have an experimental pulsed NQR apparatus equipped with a 250 W pulse power rf amplifier with the working frequency range from 0.5 to approximately 50 MHz. This range can be employed in detecting the isotopes 14N and 35Cl. The article will describe certain improvements in the circuitry of the NQR system proposed by the authors and then experimentally verified on the existing system. These modifications lead to an increased signal-to-noise ratio (SNR), thus also increasing the sensitivity of the system during the detection of substances. The main improvements are in the rf blocking circuit, which prevents the power rf pulse from reaching the preamplifier of the receiver. In this position, some impedance transformers with switched coils have been tested. The appropriate quenching circuit further reduces the penetration of the excitation pulse to this sensitive preamplifier and thus shortens the recovery time.

Název v anglickém jazyce

Sensitivity improvement in NQR based detection methods

Popis výsledku anglicky

This article presents an approach to sensitivity improvement in a detection method based on nuclear quadrupole resonance (NQR); this technique is widely applied in, for example, the detection of explosives. We have an experimental pulsed NQR apparatus equipped with a 250 W pulse power rf amplifier with the working frequency range from 0.5 to approximately 50 MHz. This range can be employed in detecting the isotopes 14N and 35Cl. The article will describe certain improvements in the circuitry of the NQR system proposed by the authors and then experimentally verified on the existing system. These modifications lead to an increased signal-to-noise ratio (SNR), thus also increasing the sensitivity of the system during the detection of substances. The main improvements are in the rf blocking circuit, which prevents the power rf pulse from reaching the preamplifier of the receiver. In this position, some impedance transformers with switched coils have been tested. The appropriate quenching circuit further reduces the penetration of the excitation pulse to this sensitive preamplifier and thus shortens the recovery time.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20201 - Electrical and electronic engineering

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2014

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Proceedings of PIERS 2014 in Guangzhou

ISBN

978-1-934142-28-8

ISSN

1559-9450

e-ISSN

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Počet stran výsledku

5

Strana od-do

2360-2364

Název nakladatele

Neuveden

Místo vydání

Neuveden

Místo konání akce

Guangzhou

Datum konání akce

25. 8. 2014

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000393225900523