A receive system for high Q antennas in nqr and a method of detecting substances

Abstract

A receiving system ( 11 ) for connection to an antenna arrangement ( 19 ) for detecting response signals from a substance having quadrupolar nuclei excited so as to produce nuclear quadrupole resonance in certain of the quadrupolar nuclei. A method for receiving a response signal via the antennae arrangement ( 19 ) is also described. The receiving system ( 11 ) includes an amplifier ( 17 ) to amplify the received response signal from the antenna arrangement ( 19 ) for subsequent processing, a matching section ( 15 ) to match the amplifier ( 17 ) to the antenna ( 19 ), and an isolating switch ( 13 ) to isolate the antenna from the receiving system ( 11 ). The matching section ( 15 ) noise matches the receiving system ( 11 ) to the antenna ( 19 ) during a receiving period to reduce the Q factor of the antenna without significantly degrading the signal to noise ratio. The isolating switch ( 13 ) isolates the receiving system ( 11 ) from the antenna ( 19 ) during a transmitting period when an excitation signal is transmitted by the antenna ( 19 ) to irradiate the substance. It also electrically connects the receiving system ( 11 ) to the antenna during the receiving period immediately after the transmitting period.

Description

technical field [0001] The present invention relates to nuclear quadrupole resonance (NQR) spectroscopic devices and methods of detection using such devices. In particular, the present invention relates to devices which require extended bandwidth, phase stabilization or reduced Q when receiving a response signal originating from a substance comprising quadrupolar nuclei in an appropriately excited state. These devices specifically consist of a high-Q resonant circuit antenna designed to intercept changes in the magnetic field and convert them into an amplified output voltage so that the NQR response signal can be recorded. [0002] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising" is understood to mean the inclusion of a specified integer or group of integers, but not Excludes any other integer or group of integers. Background technique [0003] The following discussion of the backgro...

AI Technical Summary

Problems solved by technology

There is no technical specification of the optimum receiver bandwidth or the optimum characteristics of a constant receiver phase across a temperature range of an NQR signal

Also, the use of capacitors in a feedback loop, which is not convenient to use in an industrial amplifier, creates the possibility of high frequency vibration patterns, making the NQR signal difficult to understand

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