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Quantum Networks: The Building Blocks
Published in Jonathan P. Dowling, Schrödinger’s Web, 2020
This thing is cylindrically shaped and very small; as you can see in the figure, it is a micron in diameter, which is about a hundred times smaller than the diameter of a human hair. The quantum dot can be excited either electrically or optically with a laser pulse. We prefer the latter method, since we clock the laser pulses. In the ideal case, a single photon would come out each nanosecond. A nanosecond is one-millionth of a second, that is, a million single photons per second – a respectable rate. However, exciting the quantum dot with a laser at the same wavelength as the photon that the dot will emit comes at a cost. Sometimes a stray photon from the exciting laser itself gets caught in the gun, and the gun can emit two photons at once – one from the atom and the other the stray photon from the laser. After decades of work, this probability of getting two photons per shot is now much less than 1%.
An Introduction to VNPs and Nanotechnology
Published in Nicole F Steinmetz, Marianne Manchester, Viral Nanoparticles, 2019
Nicole F Steinmetz, Marianne Manchester
Nano is a somewhat fashionable term; in common speech, it is used as a prefix to denote something that is smaller than usual. As of this writing, the term “Apple iPod nano” is the first hit on a Google search of the term “nano”. The word nano is derived from the ancient Greek word for dwarf. In a scientific context the prefix nano is used to describe “a billionth of something”. A nanometer is a billionth of a meter (10−9 m = 1 nm), and a nanosecond is a billionth of a second (10−9s = 1 ns).
New Technology and the Future
Published in Ervan Garrison, A History of Engineering and Technology Artful Methods, 2018
The final arbitrar of the vicissitudes of analog and digital computing lay in the simple notion of speed. The use of electromechanical relays required 1 to 10 milliseconds (10−3 sec) to open or close due to the inertia of the mechanical parts. In a tube or transistor the element being moved are electrons. These masses are 9 × 10−28 grams as compared to relay contacts whose masses are about 1 gram. With almost no inertia to overcome, the electronic circuit operates almost instantaneously. Total time in the early computers, like ENIAC (Electronic Numerical Integrator and Calculator), to actuate the other parts of a circuit was 5 microseconds (10−6 sec). At the present time electronic circuits operate in nanoseconds (10−9 sec). ENIAC developed by John W. Mauchley and J. Prosper Eckert at the University of Pennsylvania, School of Electrical Engineering, had microsecond speed that simply was a thousand times faster than the best analog relay machines. Why was this speed so important? Simply because many physical problems involve multiple parameters such as weather with say n multiplications at t time intervals over 5 space points. Then the total calculation is proportional to nt(1), nts, nts2 nts3,…, ntsn. Thus for three spatial dimensions one can quickly have 750 million multiplications.
Development of a Signal Processing Software for Scintillation Detectors and Implementation on an FPGA for Fast Sensing
Published in Nuclear Technology, 2023
Benjamin Wellons, Rishya Sankar Kumaran, Sanghun Lee, Shikha Prasad
In this work, we discuss the development of an open-source code, RadSigPro 1.0aThe RadSigPro code can be accessed at https://github.com/NeutronNeutrinoSensing/RadSigPro., which allows quick processing of picosecond- to nanosecond-long pulses. This processing includes key pulse data analysis methods: pulse height distribution (PHD), pulse shape discrimination (PSD), and time of flight (TOF). We will also present a field programmable gate arraybThe FPGA implementation can be accessed at: https://github.com/NeutronNeutrinoSensing/FPGA. (FPGA) design for on-the-fly processing of detected pulses. These implementations will be applied to measurements made with organic scintillation detectors (EJ-309) with computation times of 4 to 8 ns for PHD determination (2 ns after maximum amplitude) and 5 ns for PSD determination per pulse after it is triggered.
Gold nanoparticles produced by laser ablation in distilled water assisted by electric field
Published in Radiation Effects and Defects in Solids, 2022
Mariapompea Cutroneo, Vlamidir Havranek, Jiri Vacik, Lorenzo Torrisi, Letteria Silipigni, Petr Malinsky, Anna Mackova
The laser can be employed for different applications, from welding (8) to cleaning (9) and producing nanoparticles (10). The laser ablation method is a powerful, versatile, clean and fast technique to produce a wide range of nanoparticles in different environments (in vacuum (11), in air (12), in gases (13) and in liquids (7)). The key parameters controlling the NPs size and shape are the laser energy, fluence, wavelength and pulse duration, and the environment in which the laser ablation occurs. Depending on the thermal properties of the target material, the laser-ablation process seems to be more efficient in water than in air as shown by Patel et al. (14). It was observed that the best environment to produce uniform nanoparticles size distribution by the laser-ablation is water (15). Despite the use of femtosecond and picosecond lasers, the most widely used laser to produce nanoparticles is the nanosecond laser. The two main mechanisms for removing material by nanosecond lasers are the thermally induced explosive ejection of molten droplets with sizes ranging between nanometers and micrometers from the target and the thermal vaporization of ionic or atomic species from the laser-irradiated target surface. The shape, structure, and size of metallic NPs influence their catalytic properties and morphology. By applying an electric field during the laser ablation in liquid NPs with controlled sizes and unique morphology could be produced (16).
Microchannel fabrication and metallurgical characterization on titanium by nanosecond fiber laser micromilling
Published in Materials and Manufacturing Processes, 2020
Laser micromachining system equipped with SPI make fiber laser source of 50W with nanosecond pulse waveform. The laser has pulse tune technology, which allows programmed waveform to deliver in CW and pulsed mode. Gaussian beam profile of laser beam helps to achieve high fluence with effective processing of metals and nonmetals. For high-quality machining, it is required to have laser pulses with shorter pulse duration. So the machining surface was found better in nanosecond as compared to milli- or microsecond pulses. It is equipped with suitable optics to focus laser beam on very small spot size for higher fluence and miniature product fabrication. The collimated beam expanded through beam expander and with focusing lens (F50), focused to small spot size of 7 µm. Laser cutting head has provision to supply assist gas coaxially through nozzle. There are three ports that can supply gas up to 15 bar at 120° angle. Dry compressed air is supplied from compressor and regulated by pressure control valve. Specification of laser source shown in Table 1.