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© 2014 American Chemical Society. In this paper, new steps toward a better understanding and utilization of high-pressure high-temperature nanodiamonds (NDs) containing nitrogen-vacancy (NV) centers have been taken. NV--related long-term luminescence of oxygenated particles increased in comparison to plasma hydrogenated NDs' NV- luminescence. The optically detected NV- electron spin resonance process can be also significantly affected by ND termination. For H-terminated ND particles the NV- to NV0 conversion energy is lower than the NV- excitation energy, so that the delocalized triplet electrons can be more easily released from the original positions and drawn to the electron-attracting localities in the material. The final result of this study was application of luminescent NDs in cells, showing the detectability of luminescent NDs in a standard confocal microscope and ND subcellular distribution in the cells by TEM.

Many types of detectors like stilbene, NE-213 etc. in conjunction with photomultiplier loaded with low working resistance produce pulses of approximately 100 ns length and contain information about deposited particle in the trailing edge. Using fast analog to digital converters (ADC) and field-programmable gate array (FPGA) it is possible to create a spectrometric system working in mixed gamma and neutron fields which is not loaded dead time. The count rate of processed pulses can reach more than one million per second. Such a high count rate of processed pulses can be achieved due to the pulse processing is implemented in FPGA. The output of this pulse processing is amplitude which describes the energy of deposited particle and discrimination parameter whereby it is possible to discriminate photons and neutrons. To increase the dynamic range of energy of detectable particle the signal from photomultiplier is separated into two branches with different amplification. Each branch is digitalized by separate ADC. Components from which the system is composed are so light that the spectrometer can be easily transported. Its weight is less than 3 kilograms. Spectrometer was tested in the research reactor LR-0 in Rez near Prague (Czech Republic). The measured data was processed using deconvolution into a neutron flux density and compared with nowadays used analog spectrometer and simulation result. Measured neutron spectrum of Cf-252 is included. Článek popisuje spektrometr pro měření ve směsných polích gama/neutrony. Analogový signál z detektoru je vzorkován AD převodníky pracujícími na frekvenci 1 GHz. Předzpracování signálu probíhá v FPGA a tím je zajištěna vysoká propustnost systému bez mrtvé doby. Spektrometr byl testován v Centru výzkumu Řež na reaktoru LR-0. Many types of detectors like stilbene, NE-213 etc. in conjunction with photomultiplier loaded with low working resistance produce pulses of approximately 100 ns length and contain information about deposited particle in the trailing edge. Using fast analog to digital converters (ADC) and field-programmable gate array (FPGA) it is possible to create a spectrometric system working in mixed gamma and neutron fields which is not loaded dead time. The count rate of processed pulses can reach more than one million per second. Such a high count rate of processed pulses can be achieved due to the pulse processing is implemented in FPGA. The output of this pulse processing is amplitude which describes the energy of deposited particle and discrimination parameter whereby it is possible to discriminate photons and neutrons. To increase the dynamic range of energy of detectable particle the signal from photomultiplier is separated into two branches with different amplification. Each branch is digitalized by separate ADC. Components from which the system is composed are so light that the spectrometer can be easily transported. Its weight is less than 3 kilograms. Spectrometer was tested in the research reactor LR-0 in Rez near Prague (Czech Republic). The measured data was processed using deconvolution into a neutron flux density and compared with nowadays used analog spectrometer and simulation result. Measured neutron spectrum of Cf-252 is included.