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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 9:27 |
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Conference: Bucharest University Faculty of Physics 2011 Meeting
Section: Biophysics; Medical Physics
Title:
A home-built pulse NQR spectrometer for detection of the 14N nuclei
Authors:
L. C. Giurgiu(1), A. Radu(1), A. Ionescu(1), E. Busuioc(1), S. Ilie(2), S. Toba(2), V. Vasilescu(2), A.C. Gheorghe(3)
Affiliation:
1) Faculty of Physics, University of Bucharest,
2) Mira Technologies Group SRL
3) IFIN-HH
E-mail
liviu.giurgiu@gmail.com
Keywords:
Abstract:
Nuclear Quadrupole Resonance (NQR) is based on the electric quadrupole interaction between the nuclear electric quadrupole moment and the electric field gradient at the nucleus due to surrounding charges. The electric field gradient hence the quadrupole resonance properties depends strongly on the molecular structure. Therefore, each substance is characterized by its own NQR frequencies. The applied RF radiation drives transitions between the quadrupole energy levels of an atomic nucleus. The radiation emitted by the excited nuclei whilst in their non-equilibrium state can then be detected.
In this work a low power pulse NQR spectrometer for direct detection of the transitions between the quadrupole energy levels of the 14N nuclei is proposed. The system contains seven units: RF signal synthesizer, power amplifier (100 W), RF lock-in amplifier, pumping coil and a network matching circuit, detection coil and a low noise preamplifier, sample header with a precision thermostat and dual processor computer with a FPGA card. The spectrometer is capable of detecting 1 g of sodium nitride.
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