0022]FIG. 2 is a basic block diagram of an embodiment of the pulse oximeter system 10 that is capable of transmission mode photon density wave emission and detection. The configuration and operation of the system 10 in transmission mode may enable deep penetration of the photon density waves into a region of interest in a patients tissue. As in FIG. 1, the system 10 illustrated in FIG. 2 includes the monitor 12 and the sensor 14. In FIG. 2, the monitor 12 and the sensor 14 include features capable of cooperating to transmit photon density waves into one side of a patients tissue and out of a generally opposite side for detection. Specifically, in FIG. 2, the monitor 12 is illustrated as including various functional components that facilitate transmission of photon density waves through an emitter-side fiber optic cable 22 to the sensor 14. The sensor 14 is physically configured such that, when properly attached to a patients tissue 24, the photon density waves from the emitter-side fiber ...
Two-photon absorption spectra of Al|sub>0.4|/sub>Ga|sub>0.6|/sub>As/GaAs quantum wells in static electric fields are investigated experimentally. A drastic field-induced increase in the absorption peaks at energies close to |i>half|/i> the bandgap energy is reported for the first time. In particular, we observed the rise and red-shift of a peak corresponding to |i>half|/i>the lowest light-hole exciton energy not seen in non-biased quantum wells. For moderate fields, the results agree with a theory based on a zero-bias infinite- level model, whereas the large peak value at stronger fields is explained by a two-level model. Contrary to bulk GaAs, a large value of the third order optical susceptibility is predicted |i>just below|/i> the two-photon absorption edge at which the biased quantum wells are highly transparent. This gives a large figure of merit for ultrafast optical nonlinearities. |p> We have also theoretically and experimentally investigated time-resolved two-photon absorption in bulk GaAs and
Treatment Planning for Photon Radiotherapy will be performed using the Planning Systems available at the Department of Radiation Oncology in Heidelberg, Germany (including Masterplan/Nucletron, Virtuos-Konrad/Siemens, or Precisis/STP/Stryker-Leibinger, or the Tomotherapy Software). Carbon ion and proton RT planning is performed using the treatment planning software PT-Planning (Siemens, Erlangen, Germany) including biologic plan optimization. Biologically effective dose distributions will be calculated using the a/ß ratio for meningioma as well as for the endpoint late toxicity to the brain. Patient positioning prior to radiotherapy will be evaluated by comparison of x-rays to the DRRs. Set up deviations ,3mm are corrected prior to radiotherapy.. To the target volume defined for photon treatment, a total dose of 52.2 Gy E - 57.6 Gy E is applied in single fractions of 1.8Gy E. In the 3Gy E Photon arm, photon radiotherapy will be delivered to a total dose of 45 Gy E in 15 fractions. ...
We present the first study of two-photon absorption (TPA) of solvated molecules based on direct evaluation of TPA cross sections from the quadratic response of time-dependent perturbations. A set of prototypical two-photon (TP) chromophores has been selected and analyzed: a pure pi system (t-stilbene) and its substituted homologs obtained employing a donor (D) and an acceptor (A) group to probe the solvent effects along the series pi, D-pi-D, A-pi-D, and A-pi-A. For the selected systems we have calculated the TPA cross sections in different environments by means of the polarizable continuum model. The data have been analyzed to evaluate how the structural and environmental parameters contribute to the final two-photon absorption cross section. These include molecular structure, geometry relaxation in solution, polarity, and refractive index of the solvent. The performances of the three common functionals SVWN, BLYP, and B3LYP have been compared. The results show a significant solvent dependence ...
Abstract: An extensive series of pyrazole aluminum compounds containing an Al2N4 center as a pseudoconjugated system were theoretically investigated for their one-photon absorption and two-photon absorption (OPA and TPA) properties by density functional theory (DFT) and Zerners intermediate neglect of differential overlap (ZINDO) methods. The results indicate that pyrazole aluminum compounds are good TPA materials and that the TPA maximal absorption cross-section (δmax) can reach 2860.1 GM (1 GM=10-50 cm4·s·photon-1). By incorporating electron-acceptors in the central core, a π-conjugated bridge and terminal groups, the OPA and TPA properties can be modulated. This research provides strategies for the enhancement of molecular TPA in the target region. The origin of the large δmax of some of the studied molecules was determined using a three-level energy model. We conclude that an increase in the intramolecular charge transfer can enhance δmax. Moreover, the pyrazole aluminum compounds ...
And this is how they know which slit the photon went through? Exactly. They use a small optical fiber to collect only the top or bottom lobe of one photon from the pair, and send the other one onto the double-slit, aligned so that the top lobe hits the top slit only, and the bottom lobe hits the bottom slit only. If they put a similar detector behind the slits, they can confirm that when they look for a photon arriving behind the slits at the same time that one hits the top/bottom detector, they only see photons in the appropriate slit, as seen in the figure at right. In this case, theyre looking in the "near field," which means that the fibers to detect the photons are right behind the slit, too close to see an interference pattern.. So, how does this not destroy the interference? Well, it does while theyre doing this measurement. Having used this measurement to show that the top/bottom correlation works, though, they move the detector behind the slits into the "far field," which means more ...
We propose photon energy qubits and schemes for photon energy entanglement characterization. Bell inequality violation for energy qubits and complete Bell state analysis are demonstrated theoretically. Photon energy superposition state detection is performed by a two-photon absorption interferometer based on electron transition path interference. The scheme can be realized at room-temperature by two-level systems and semiconductor devices.. ©2009 Optical Society of America. Full Article , PDF Article ...
Integrated optics has emerged as a promising solution to the electronic interconnect bottleneck, enabling high bandwidth density and low power consumption. Recently, confining photochemical and physical reactions in a micro-volume has given an extra dimension to optical interconnection using glass or polymer. Three-dimensional waveguides can then connect, combine, or split the optical signal among any blocks in all dimensions. However, the refractive index increase is still a challenge to fabricate free-form, stable and single-mode three-dimensional buried waveguides.. This paper presents a new concept to tackle this challenge using the combination of femtosecond direct laser writing (FsDLW) in polymer and external diffusion of a gaseous monomer. FsDLW with two-photon absorption was used to initiate cross-linking following a programmed trajectory to form the waveguide core. A thermal treatment was then needed to complete cross-linking. Afterwards, a low-index monomer from a gas atmosphere was ...
In this paper we develop an analytical model for the soliton self-frequency shift, which includes second- and third-order dispersion, self-steepening, the full Raman term, and, for the first time to our best knowledge, the effect of two-photon absorption (TPA). We show that TPA can have a significant effect on soliton dynamics in soft-glass materials such as chalcogenides, by severely depleting a soliton and thereby limiting the achievable redshift. Based on the model, we derive a nonlinear loss length after which the redshift is effectively halted by TPA, which proves to be a useful design tool.. ©2012 Optical Society of America. Full Article , PDF Article ...
Extreme photon localization is applicable to constructing building blocks in photonic systems and quantum information systems. A finding fact that photon localization in small space modifies the radiation process was reported in 1944 by Purcell, and advances in fabrication technology enable such structures to be constructed at optical frequencies. Many demands of building compact photonic systems and quantum information systems have enhanced activities in this field. The photonic crystal cavity has potential in providing a cavity that supports only the fundamental mode of (lambda/2n)^3 together with good confinement of light within a resonator. This thesis addresses experimental and theoretical aspects of building such photon localization blocks embedding active quantum nanostructures in a planar photonic crystal platform. Examples given in this thesis are (1) quantum dot photonic crystal nanolasers, (2) high-speed photonic crystal nanolasers, and (3) light-matter coupling in a single quantum ...
A photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles). The photon has zero rest mass and always moves at the speed of light within a vacuum.. Like all elementary particles, photons are currently best explained by quantum mechanics and exhibit wave-particle duality, exhibiting properties of both waves and particles. For example, a single photon may be refracted by a lens and exhibit wave interference with itself, and it can behave as a particle with definite and finite measurable position or momentum, though not both at the same time. The photons wave and quanta qualities are two observable aspects of a single phenomenon, and cannot be described by any mechanical model;[2] a representation of this dual property of light, which assumes certain points on the wavefront to be the seat of the energy, is not possible. The quanta ...
Pump-probe spectroscopy has long been useful in the elucidating ultrafast molecular phenomena. We developed a variation of time-resolved, pump-probe methodology using cross-correlation principles of the frequency-domain. An unique feature of our technique is that the low-frequency, cross correlation signal and its harmonics which contain lifetime information at high excitation frequencies can be simultaneously acquired and analyzed by a frequency spectrum analyzer. The result is that high frequency spectral information can be acquired without a fast optical detector and simultaneous acquisition of multiple harmonics reduce data acquisition time. A second key feature of this technique is that the cross-correlation signal comes primarily from the focal volume and hence microscopic imaging using this technique results in axial depth discrimination and improved spatial resolution similar in two-photon excitation microscopy. Using this technique, spectroscopic data measuring the lifetime and ...
Article Comprehensive study of energy absorption and exposure build-up factors for concrete shielding in photon energy range 0.015-15 MeV up to 40 mfp penetration depth: dependency of density, chemical elements, photon energy. Gamma ray build-up fact...
Is it possible to create a space void of photons? Or rather free from photon interference? I know single photon emitters have been made to test the behaviour of photons. However it would appear that space...well everything is jam packed with photons in various forms, and therefore observing a single photon seems impossible as its not as easy as turning out the lights. Even darkness is light and space is not the darkness our eyes feebly percieve. I ask this because it would then seem necessary to account for photons as a group or whole regarding motion and behaviour rather than an individual wave particle ...
Abstract: We analyze the second-order photon autocorrelation function $g^{(2)}$ with respect to the photon probability distribution and discuss the generic features of a distribution that result in superthermal photon bunching ($g^{(2)},2$). Superthermal photon bunching has been reported for a number of optical microcavity systems that exhibit processes like superradiance or mode competition. We show that a superthermal photon number distribution cannot be constructed from the principle of maximum entropy, if only the intensity and the second-order autocorrelation are given. However, for bimodal systems an unbiased superthermal distribution can be constructed from second-order correlations and the intensities alone. Our findings suggest modeling superthermal single-mode distributions by a mixture of a thermal and a lasing like state and thus reveal a generic mechanism in the photon probability distribution responsible for creating superthermal photon bunching. We relate our general ...
Now have a look at how one measures indistinguishability. Inthe Hong-Ou-Mandel experiment you take two consecutively emitted photons, insert a delay in the path of the first emitted photon and put the two photons on different entrance ports of a 50/50 beam splitter. If they are indistinguishable, they will leave through the same exit port because of two-photon interference. Otherwise, they will not. Now, the prerequisite for observing two-photon interference is of course that the two photons must overlap at the beam splitter. As a single experiment does not tell you much, you need to repeat the experiment several thousand times. If you revisit the Michelson interferometer experiment I outlined before,it becomes clear that having them overlap is not actually trivial. There is a non-zero probability for detecting a photon only during a time window of the length of the coherence time, so the delay between the two photons must be shorter than the coherence time in order to see two-photon ...
A single photon system consists of an excitation source, for example a laser, a single photon emitter and components collecting the emitted photons and coupling it into an optical fiber. Usually the propagation direction of the single photons is opposite to the propagation direction of the optical pump radiation.,br,,br, ,!--break--,,strong,Technology,/strong,,br, The invention is a ,a name="_GoBack",,/a,very compact single photon system, where the propagation direction of the emitted single photons corresponds to the propagation direction of the optical pump radiation.,br, ,br ...
The method was termed ELLIPSA (elliptical polarization state alteration)" and should prove to be of general applicability, being potentially quite sensitive. The fate of two-photon excited neutral molecules and atoms is most easily followed in real time by fluorescence monitoring. In the next sections we show that in spite of the small two-photon absorption crosssection, the method can be used for quantitative kinetic measurements. For some applications, it is more straightforward and leads to less ambiguous interpretation than one-photon excitation. In general, the sodium concentration decreased after the laser pulse, and returned to equilibrium at a slower rate. However, the signals also contained a large sinusoidal modulation, which at high pressures completely obliterated the desired signal. When helium was added to the gas mixture, the sinusoidal frequency increased in accordance with the difference in the velocity of sound. This implies that the modulation is due to changes in the sodium ...
Description: We examine the phenomenology of the production, at the 13 TeV Large Hadron Collider (LHC), of the production of a heavy resonance $X$, which decays via other new on-shell particles $n$ into multi- (i.e.\ three or more) photon final states. In the limit that $n$ is light compared to $X$, the multi-photon final state may dominantly appear as a two photon final state because the $\gamma$s from the $n$ decay are highly collinear and are not resolved. We discuss how to discriminate this scenario from $X \rightarrow \gamma \gamma$: rather than discarding non-isolated photons, it is better to relax the isolation criterion and instead form photon jet substructure variables. The spins of $X$ and $n$ leave their imprint upon the distribution of pseudorapidity gap $\Delta \eta$ between the apparent two photon states. Depending on the total integrated luminosity, this can be used in many cases to claim discrimination, although the case where $X$ and $n$ are both scalar particles cannot be ...
Image acquisition and treatment under deep inspiration breath hold (DIBH) has been demonstrated to reduce treated volumes and doses to organs at risk (OARs) for photon radiotherapy but has not been investigated in the context of proton radiotherapy. The objective of this registry study is to prospectively evaluate deep inspiration breath hold CT scans for use in proton radiotherapy treatment planning and obtain dosimetric data to assess for changes in target volume, planning volumes and doses both to tumor and organs at risk using the SpiroDynrX (SDX) deep inspiration breath hold system as compared to free breathing and 4D CT scans. Patients will be treated with photon therapy. This is a prospective non-randomized, single arm, single institution registry study of patients undergoing definitive external beam photon radiotherapy in our department. Deep inspiration breath hold CT scans will be obtained in our department in the treatment position at the time of CT simulationin addition to the ...
Elevated nitric oxide (NO) levels perform an important pathological role in various inflammatory diseases. Developing NO-activatable theranostic materials with a two-photon excitation (TPE) feature is highly promising for precision imaging and therapy, but constructing such materials is still a tremendous challenge
Coordination coupling induced self-assembly of ZnS microparticles was performed with the help of a π-conjugated sulphur-terminal Zn(ii) complex ZnS2L (L = N-hexyl-3-{2-[4-2,2′:6′,2′′-terpyridin-4′-yl-phenyl]ethenyl}-carbazole). The interactions between ZnS and ZnS2L components at the interface, which were an
The Photon IMU Shield gives the Photon motion-sensing ability by connecting it to an all-in-one 9DOF IMU (a lot like the LSM9DS0). With this shield, the Photon will be able to sense linear acceleration, angular rotation, and magnetic fields. The Photon OLED Shield connects the Photon up to a blue-on-black OLED. The display is small, but its perfect for visualizing IMU data or printing readings from any of the other shields. Finally, no ecosystem is whole without a Prototyping Shield. This simple little board adds some prototyping space in proximity to the Photons I/O pins and power buses. ...
Photon Calc is an iPhone app that displays cross sections for gamma / x-ray photons, fluorescence and edge energies, and allows you to calculate the transmission and attenuation for an arbitrary photon energy
Two-photon excitation and time-resolved fluorescence: I. The proper response function for analysing single-photon counting experiments ...
Well, as with all things quantum, bizarre is the norm. Recently, particle physicists in Israel have demonstrated the entanglement of two photos that "dont exist at the same time". Time-separated entanglement is predicted by standard quantum theory, but has until now never been successfully demonstrated.. Recall that superposition allows a photon to be in two states at once, but once measured, the uncertainty of this superposed waveform (of the particle) "collapses" into one or the other state (vertically or horizontally polarized). The uncertainty also applies to two-particle systems; each photon in a two photon system can be forced into an uncertain, both-at-once state, but also remain correlated (entangled) despite the uncertain state of either. And, again, once you try to determine the spin state of one photon, its superposed state collapses, and, the other particles state collapses.. We might assume this to be true for even for two entangled pairs of photons (separated by any arbitrary ...
Blue light (400-430 nm) is known to induce lethal effects in some species of fungi by photo-oxidation caused by the excitation of porphyrins but the mechanisms involved remain poorly understood. In this work, we exposed the yeast Saccharomyces cerevisiae to a high density light flux with two-photon excitation (830 nm equivalent to a one-photon excitation around 415 nm) and used quasi real-time visualization with confocal microscopy to study the initiation and dynamics of photo-oxidation in subcellular structures. Our results show that the oxidation generated by light treatments led to the permeabilization of the plasma membrane accompanied by the sudden expulsion of the cellular content, corresponding to cell death by necrosis. Moreover, excitation in the plasma membrane led to very fast oxidation and membrane permeabilization (| 60 s) while excitation at the center of the cell did not induce permeabilization even after a period exceeding 600 s. Finally, our study shows that the relationship between the
Optical parametric oscillation (OPO) and optical parametric generation (OPG) have widely been used for producing tunable radiations. In this paper we prese
Eesti Teadusinfosüsteem koondab informatsiooni teadus- ja arendusasutuste, teadlaste, teadusprojektide ning erinevate teadustegevuste tulemuste kohta.
Time-correlated photon counting experiments in life and material sciences demand photodetectors with single photon sensitivity, low noise and high time res
Under the photon theory of light, a photon is a discrete bundle (or quantum) of electromagnetic (or light) energy. Photons are always in motion and, in a vacuum, have a constant speed of light to...
Вид документа : Однотомное издание Шифр издания : Автор(ы) : Kosunen A., Jarvinen H., Vatnitskij S. Заглавие : Intercomparison of radiotherapy treatment planning systems using calculated and measured dose distributions for external photon and electron beams Выходные данные : Helsinki, 1991 Колич.характеристики :49 с Серия: Sateilyturvakeskus, ISSN 0781-1705; STUK-A98 Примечания : ; Библиогр.: с.17-18 ISBN, Цена 951-47-4332-6: Б.ц. ГРНТИ : ; 76.29.62 Ключевые слова (Своб.индексиров.): 0 ; система планирования радиотерапии; фотонные электронные пучки Перейти к источнику в Интернете: Intercomparison of radiotherapy treatment planning systems using calculated and measured dose distributions for external photon and electron beams Доп.точки доступа: ...
This paper presents an interactive algorithm for simulation of light transport in clouds. Exploiting the high temporal coherence of the typical illumination and morphology of clouds we build on volumetric photon mapping, which we modify to allow for interactive rendering speeds --- instead of building a fresh irregular photon map for every scene state change we accumulate photon contributions in a regular grid structure. This is then continuously being refreshed by re-shooting only a fraction of the total amount of photons in each frame. To maintain its temporal coherence and low variance, a low-resolution grid is used, and is then upsampled to the density field resolution in each frame. We also present a technique to store and reconstruct the angular illumination information by exploiting properties of the standard Henyey-Greenstein phase function, namely its ability to express anisotropic angular distributions with a single dominating direction. The presented method is physically-plausible, ...
Last week Jetpack announced that its Photon image service added support for the WebP image format, which provides up to 34% size reduction for served images when compared JPEG images of the same visual quality. For Photon users this translates into faster-loading pages.. WebP is not yet natively supported by all browsers, so Photon will auto-detect the visitors browser and serve the images in the best quality/speed possible.. I spoke with Jetpack team leader George Stephanis at WordCamp US about the improvements to Photon, and he broke it down for us in the video interview below.. ...
This movie shows how ultraviolet "light" can break apart a molecule. You need the latest version of the Flash player to see this movie.. Photons are little bits of light. Photons carry energy. When a photon hits a nitrogen molecule, it adds energy to the molecule. The molecule has chemical bonds (they work a bit like stretchy rubber bands!) holding its atoms together. Sometimes the energy from the photon breaks the bond between the two nitrogen atoms. The atoms fly apart! This is called photodissociation.. Photons of ultraviolet (UV) light carry more energy than photons of visible light carry. It takes high-energy UV photons to break nitrogen apart!. ...
Photons are little bits of light. Photons carry energy. When a photon hits a molecule, it adds energy to the molecule. The molecule has chemical bonds (they work a bit like stretchy rubber bands!) holding its atoms together. Sometimes the energy from the photon breaks the bond between some of the atoms in a molecule. The atoms fly apart! This is called photodissociation.. Photons of ultraviolet (UV) "light" carry more energy than photons of visible light carry. Sometimes it takes high-energy UV photons to break a molecule apart!. ...
Detecting corneal cells metabolic alterations may prove a valuable tool in the early diagnosis of corneal diseases. Nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are autofluorescent metabolic co-factors that allow the assessment of metabolic changes through non-invasive optical methods. These co-factors exhibit double-exponential fluorescence decays, with well-separated short and lifetime components, which are related to their protein-bound and free-states. Corneal metabolism can be assessed by measuring the relative contributions of these two components. For that purpose, we have developed a wide-field time-gated fluorescence lifetime microscope based on structured illumination and one-photon excitation to record FAD lifetime images from corneas. NADH imaging was not considered as its UV excitation peak is regarded as not safe for in vivo measurements. The microscope relies on a pulsed blue diode laser (λ=443 nm) as excitation source, an ultra-high speed gated ...
The factors that propel the growth of the global Photonic Crystals market research report include increase in demand for photonic crystals in LEDs and growing R&D activities.
We investigate the collective interaction of a multi-atom three-level ladder system with an environmental incoherent reservoir. The exact solution of the master equation that describes such a system of atoms emitting distinguishable or indistinguishable photons on interaction with an incoherent reservoir is obtained. The quantum decay interference effects have no influences over steady-state distribution of population among the energy levels. However, the photon statistics of the collectively emitted photons are different in this case. In particular, the normalized second-order photon correlation function shows a minimum in its value for the photons generated on lower atomic transition in a system with orthogonal dipoles. The minimum is due to the steady-state amplified spontaneous emission by the incoherent applied fields. Submitted to: J. Phys. B: At. Mol. Phys. PACS numbers: 42.50.Fx, 42.50.Lc, 42.50.Ar Incoherent excitation of few-level multiatom ensembles 2
Detail akcie PHOTON ENERGY Aktu ln kurzy na burze online, obchody, cena k n kupu i prodeji v ka d okam ik. Historick kurzy, grafy.
The present invention to provides methods and apparatus for studying photon migration using signal modulation techniques such as time, frequency and phase modulation. The photon migration data may then be converted, using the principles of time-resolved spectroscopy, to determine the concentration of an absorptive constituent in a scattering medium, such as the concentration of hemoglobin in a brain of other tissue. The methods and apparatus of the present invention provide as a specific embodiment, a dual wavelength phase modulation system which allows the clinical application of time resolved spectroscopy in a commerically feasible embodiment.
In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those ...
HVA ER PHOTON?. Et photon er en lyspartikkel. All lysenergi som vi mottar, enten fra solen eller kunstige kilder, også alle farger, som er refleksjon av lys, er photoner som gir inntrykk til netthinnen i våre øyne. I tillegg til dette synlige lyset, finnes det andre typer lys som vår netthinne ikke registrerer. Dette lyset kan ha en kortere eller lengre bølgelengde enn det synlige lyset.. Photoner med kortere bølgelengde er; UV stråler, røntgen stråler, gamma stråler osv. Photoner med lengre bølgelengde er; infrarøde, mikrobølger, radio og TV bølger osv.. Photon Platinum® sender ut infrarøde bølger med en bølgelengde som er svært nær opptil det synlige lyset. Kortere bølgelengder er svært skadelige, og vi bør absolutt ikke utsettes for en slik form for stråling. Heldigvis har vi ozonlaget som beskytter oss mot disse fra verdensrommet. Lange bølgelengder har ikke mulighet til å påvirke noen spesielle biologiske reaksjoner. Kun mellombølger i gruppen infrarødt, i ...
Back in 2011, Sprint launched the Motorola Photon 4G and now if the rumors are to be believed, a successor for the Photon 4G has been lined up and is...
Our perception of color is an extraordinarily complex matter. In the prehistoric, ancient, and medieval worlds, color was a straightforward matter. You looked at an object and it was red or green (unless you were color-blind) or blue or yellow. However, Newton came along and got everything stirred up with his prisms and lenses. (These scientists are always troublemakers! Optics, relativity, evolution, climate change why don t they stay home and watch football on TV?). Light is composed of photons which, I take it are colorless; there aren t blue photons, pink photons, or mauve photons. Even if they did have color, what could we illuminate them with in order to test them for hue, tint, or shade? We are told that light has different wavelengths which constitute a spectrum, some of which we can see, some of which other animals can sense, and some of which we can detect with sophisticated technologies. Here we encounter one of those wonderful conundrums of modern physics; Photons are light particles ...
Purpose: To obtain an analytical empirical formula for the photon dose source term in forward direction from bremsstrahlung generated from laser-plasma accelerated electron beams in aluminum solid targets, with electron-plasma temperatures in the 10-100 keV energy range, and to calculate transmission factors for iron, aluminum, methacrylate, lead and concrete and air, materials most commonly found in vacuum chamber labs. Methods: Bremsstrahlung fluence is calculated from the convolution of thin-target bremsstrahlung spectrum for monoenergetic electrons and the relativistic Maxwell-Juettner energy distribution for the electron-plasma. Unattenuatted dose in tissue is calculated by integrating the photon spectrum with the mass-energy absorption coefficient. For the attenuated dose, energy dependent absorption coefficient, build-up factors and finite shielding correction factors were also taken into account. For the source term we use a modified formula from Hayashi et al., and we fitted the ...
A system for removing the effects of Compton scattering in systems such as tomographic scanning and radioisotope imaging arrangements, which detect gamma rays, utilizes the smoothness of the Compton component over the image to reduce computing time. Data responsive to energy states of the photons which are detected are received and values corresponding thereto are stored in at least one memory location. In some embodiments, where imaging is the ultimate function of the gamma ray detection system, the data correspond to predetermined image grid points. Also, the data which is stored is processed so as to be separated into a first data set corresponding to unscattered ones of the detected photons and a second data set corresponding to scattered ones of the detected photons. Such processing utilizes least squares fitting analysis, such as the known Golub method. The first data set is summed within specified limits, for determining a number of the unscattered ones of the detected photons. A scatter free
In this paper we summarize and discuss the modern technology and systems, studied and established by our research group, for performing the detection and special analysis incorporated with the super-h
A measurement of the triple-differential cross section, d3σ/(dpγTdηγdηjet) , in photon + jets final states using a data sample from proton-proton collisions at √s = 7 TeV is presented. This sample corresponds to an integrated luminosity of 2.14 fb−1 collected by the CMS detector at the LHC. Photons and jets are reconstructed within a pseudorapidity range of ,η, , 2.5, and are required to have transverse momenta in the range 40 , pjetT , 300 GeV and pjetT , 30 GeV, respectively. The measurements are compared to theoretical predictions from the sherpa leading-order QCD Monte Carlo event generator and the next-to-leading-order perturbative QCD calculation from jetphox. The predictions are found to be consistent with the data over most of the examined kinematic region ...