Noise-resilient multi-frequency surface sensor for nuclear quadrupole resonance

Peshkovsky, Alexey S.; Cattena, Carlos J.; Cerioni, L.; Osán, Tristán Martín; Forguez, J.; Peresson, W.J.; Pusiol, D. J.

doi:10.1016/j.jmr.2008.07.003

Cited by 6 publications

(3 citation statements)

References 11 publications

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“…In NQR, nuclei with spin ≥ 1 have an electric quadrupole moment so that their energies are split by an electric field gradient, created by the electronic bonds in the local environment. According to the principles of quantum mechanics, the quadrupole Hamiltonian for NQR energy levels is written as [8]…”

Section: Nqr Explosive Detection Principlementioning

confidence: 99%

Study of Relationship between NQR Signal Amplitudes and Nitrogen Contents in Explosive Simulants

Hao

Geng

Huang

2013

AMM

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This paper investigated the relationship of the nuclear quadrupole resonance (NQR) signal amplitudes with nitrogen contents and frequencies of explosive simulants based on the NQR explosive detection principle. The NQR signals of urea, urotropine and sodium nitrite were detected by experiment at room temperature, and the signal spectra of the nitrogenous compounds with different weights were obtained. The results indicate that the NQR signal amplitudes of the same mimic are increasing linearly with the increase of weights under the same experimental conditions, meanwhile, the higher the frequency, the greater the signal amplitude. The NQR signal amplitudes of different mimics do not rely on the nitrogen contents, but depend on the other internal factors such as relaxation times, NQR frequencies and so on. The experimental data are consistent with the theoretical predictions. The results will be of value to the detection of NQR signals in explosives and the research on how to improve the signal-to-noise ratio (SNR).

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Section: Nqr Explosive Detection Principlementioning

confidence: 99%

Study of Relationship between NQR Signal Amplitudes and Nitrogen Contents in Explosive Simulants

Hao

Geng

Huang

2013

AMM

View full text Add to dashboard Cite

show abstract

“…The noise from external sources is dominant in remote detection, but can be successfully removed with gradiometric coils or additional antennas [14][15][16]. The internal noise however, mainly the coil's thermal noise, will remain, and its size is usually much bigger than the detected signal [2].…”

Section: Noisementioning

confidence: 99%

“…A further attempt involved the use of double resonance techniques [5,6], by indirectly detecting 14 N via its influence on 1 H. This technique gives a really big S=N enhancement but requires a sophisticated apparatus, with a very homogeneous magnetic field and fast field switching capabilities, which are too demanding for remote detection. Recently, a modification of the above technique which removes the requirement of a homogeneous magnetic field [7,8] was demonstrated for TNT with cross-polarization from 1 H to 14 N. Here 1 H magnetization acquired in the magnetic field is transferred to 14 N nuclei, whose NQR signal is subsequently observed. Only the magnetic field average value determines the signal enhancement with typical values of 50 for the laboratory conditions, while practical values for remote detection are around 10.…”

Section: Introductionmentioning

confidence: 99%