Scanner for nuclear quadrupole resonance measurements and method therefor

Abstract

An NQR scanner for detecting the presence of a substance containing quadrupole nuclei within an object. A pulse generating means ( 1 ) generates pulse sequences that are used to irradiate the object in a pulsed magnetic field at a requisite NQR frequency for the substance to be detected. A high power RF transmit amplifier ( 2 ) amplifies the signal to produce sufficient magnetic field strength to irradiate a scan volume within which the object is disposed for detection purposes and cause an NQR transition to a detectable level within the substance if present within the object. A method for detecting the presence of a substance containing quadrupole nuclei within an object is also described.

Description

field of invention [0001] The present invention relates to a scanner and method for detecting prescribed substances using nuclear quadrupole resonance (NQR). The present invention has particular, but not exclusive, novelty in the use of NQR to detect explosives and drugs in mail, airport luggage and other packages. [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 background art is provided merely to aid in the understanding of the present invention. It is worth noting that the discussion is not an affirmation or admission that any matter referred to is or was part of the public general knowledge at the priority date of the application. [0004] NQR is considered an admissible d...

AI Technical Summary

Problems solved by technology

Third, since they cannot contain the magnetic fields produced by, for example, solenoids, they waste space not available for magnetic field irradiation

However, the inductance is still large and the coil is difficult to tune

Also, the Q of the helical coil will be very low, which will limit the detection sensitivity

[0013] Solenoid coils cannot be used because their inductance values ​​are also very large, which also shows that these coils are difficult to tune at the higher end of the NQR frequency

And because of the large number of turns, the solenoid coil is also limited in Q

It is possible to scan an item using one set of coils, where the scanned item passes between the two sets of coils, however, this system creates two problems: (i) a non-uniform magnetic field, and (ii) a single The coils are connected together to reduce their Q and sensitivity

Variable capacitors cannot be used for this purpose as they are huge and slow in implementation

Images