Photon Physics Research Articles

Two Recent Developments in QCD Spectroscopy

The presentation has two parts, the first, and main part, is devoted to the presentation of results fromthe first measurements of the production of Λ, Σ Ξ and Ω hyperons at large timelike momentutransfers of 13.6, 14.2 and 17.4 GeV/c2 made using e+e− annihilation data taken at the CESER election-positron collider at Cornell using the CLEOc detector. The measurements reveal interesting features of hyperon production systematics and timelike form factors, and provide evidence for diquark correlations in hyperon structure. The second part of the presentation is devoted to measurements of photoproduction of J/ψ near threshold energies, EG = 8 − 12 GeV, at the new photon physics facility, GlueX, at the Jefferson Laboratory. The first preliminary results are presented. These are expected to shed light on the gluon structure of protons, gluons which mediate the production of J/ψ in the reaction,γp → J/ψ → e+e−.

Intense pulsed light processing for photovoltaic manufacturing

The solar manufacturing industry continues to expand and become a key source of energy as manufacturing costs have decreased. This has led to a rapid growth in revenue and a corresponding drop in margins that has suppliers implementing solutions to further reduce the costs associated with manufacturing solar panels. Despite these improvements, solar energy derived from photovoltaics still has an energy pay-back time of at least one year with some of this is associated with heating processes. To further reduce costs, a new technology called intense pulsed light is being implemented to eliminate expensive high energy thermal processes and encourage higher throughput. The technology also includes opportunities for devices that contain thermally limited materials. The technique was originally explored when the photovoltaic industry was quite small, and has only recently begun to gather interest as the printed electronics industry realized gains. This review discusses the use of intense pulsed light in photovoltaic manufacturing, detailing the process from a photonic physics perspective, the relevant heat transfer mechanisms, as well as its impact on the major photovoltaic sectors. Demonstrations of generation 1: crystalline silicon solar cells, generation 2: thin film solar cells, and emerging technologies: hybrid organic solar cell applications are discussed. Lastly, future outlooks for intense pulsed light in the photovoltaic manufacturing sector are offered.

Hendee's Radiation Therapy Physics, 4th ed. TPawlicki, DJScanderbeg & GStarkschall. New Jersey: Wiley‐Blackwell, 2016. Hardcover 352. pp. Price: $159.95. ISBN: 978‐0‐470‐37651‐5.

This is the 4th edition of a book on the physics of radiation therapy that covers basic principles and new technologies in the field and how these apply to the clinical practice. It is a well-referenced and easy to read text. The text is designed as an alternative or supplement to other well-established books in the field of radiotherapy physics. In addition, the authors have made an extra effort to provide a concise summary of the objectives for every chapter. They even set aside a chapter on patient safety and quality improvement. This article is protected by copyright. All rights reserved.

Photons – Radiobiological issues related to the risk of second malignancies

Photons are widely used in radiotherapy and while they are low LET radiation, can still pose a risk in developing second malignant neoplasms (SMN). Due to the physics of photons that allow distribution of energy outside the target volume, out-of-field irradiation is an important component of SMN risk assessment. The epidemiological evidence supporting this risk should be augmented with radiobiological justifications for a better understanding of the underlying processes.There are several factors that impact second cancer risk which can be analysed from a radiobiological perspective: age at irradiation, type of irradiated tissue, irradiated volume, treatment technique, previous irradiation/radiological investigations. Age-dependence has a radiobiological foundation given by the higher radiosensitivity of children as compared to adult patients. However, in its 2013 report, UNSCEAR advises against generalisation of the effects of childhood radiation exposure, given the fact that these effects are strongly organ dependent. Furthermore, the age-dependent radiation sensitivity has a bimodal distribution, since aging cells present an increase in the oxidative stress, which can promote premalignant cells.Non-targeted effects such as radiation-induced genomic instability, bystander or abscopal effects could also impact on the risk of SMN. Recent studies show that beside the known cellular changes, bystander effects can be manifested through increased cell proliferation, which could be a culprit for SMN development. Furthermore, new evidence on the existence of tumour-specific cancer stem cells that are long-lived and more quiescent and radioresistant than non-stem cancer cells can raise questions about their association with SMN risk.

Black Phosphorus Quantum Dots for Hole Extraction of Typical Planar Hybrid Perovskite Solar Cells.

Black phosphorus, famous as two-dimensional (2D) materials, shows such excellent properties for optoelectronic devices such as tunable direct band gap, extremely high hole mobility (300-1000 cm2/(V s)), and so forth. In this Letter, facile processed black phosphorus quantum dots (BPQDs) were successfully applied to enhance hole extraction at the anode side of the typical p-i-n planar hybrid perovskite solar cells, which remarkably improved the performance of devices with photon conversion efficiency ramping up from 14.10 to 16.69%. Moreover, more detailed investigations by c-AFM, SKPM, SEM, hole-only devices, and photon physics measurements discover further the hole extraction effect and work mechanism of the BPQDs, such as nucleation assistance for the growth of large grain size perovskite crystals, fast hole extraction, more efficient hole transfer, and suppression of energy-loss recombination at the anode interface. This work definitely paves the way for discovering more and more 2D materials with high electronic properties to be used in photovoltaics and optoelectronics.

Photothermal effect on Fe3O4 nanoparticles irradiated by white-light for energy-efficient window applications

A significant energy loss results from the poor thermal insulations of the commercial and public buildings. Windows diffuse a large fraction of building heating and cooling energy to the external environment, representing an annual impact of 4.1 quadrillion British thermal unit of primary energy in the US. The current technology for efficient windows relies upon the double-pane insulated glass unit with an insulating gas in between. A key challenge is to reduce thermal conductivity of the windows without relying on insulating materials. The photothermal effect can be possibly utilized for particular functionalities that can collect solar energy for reducing heat loss. The insulation efficiency is quantified through the U-factor, defined as the ratio of the heat flux (H) per unit area through the pane to the difference (ΔT) between the window interior surface and exterior temperatures. Upon solar irradiation, single-panes can “self-heat” via the photothermal effect from the nanoparticle coatings. This can effectively reduce ΔT for enhanced thermal insulation. In this study, the photothermal effect on Fe3O4 nanoparticles stimulated by solar light was investigated for nanoparticles in solutions and as thin films for energy–efficient windows. The Fe3O4 nanoparticles were surface-functionalized with different polymers to modulate colloidal stability and for the investigation of the photothermal effect. The photothermal heating efficiencies of Fe3O4 with different surface coatings were found to be much greater under the white-light irradiation than near infrared (NIR) in both aqueous suspension and as thin films. The mechanism for the photothermal effect of Fe3O4 was identified in terms of its band structure. Both Urbach energy and band gap were obtained based on absorption spectra of various Fe3O4 nanoparticles. The Urbach “tail” was found consistent with nanoparticle surface defect structures, while the band gap (~3.1eV) corresponded to the electronic transitions in the octahedral site of Fe3O4. We also discuss the absorption-based photonic physics responsible for the much-enhanced photothermal heating by white-light as compared with NIR. Based on the photothermal heating, the U-factors were obtained with the nanoparticle coatings that show promise in producing energy efficient windows.

Observation of pair tunneling and coherent destruction of tunneling in arrays of optical waveguides

We report on the experimental realization of a photonic system that simulates the one-dimensional two-particle Hubbard model. This analogy is realized by means of two-dimensional arrays of coupled optical waveguides, fabricated using femtosecond laser inscription. By tuning the analogous "interaction strength", we reach the strongly-interacting regime of the Hubbard Hamiltonian, and demonstrate the suppression of standard tunneling for individual "particles". In this regime, the formation of bound states is identified through the direct observation of pair tunneling. We then demonstrate the coherent destruction of tunneling (CDT) for the paired particles in the presence of an engineered oscillating force of high frequency. The precise control over the analogous "interaction strength" and driving force offered by our experimental system opens an exciting route towards quantum simulation of few-body physics in photonics.

Recent progress in semiconductor excitable lasers for photonic spike processing

Recently, there has been tremendous interest in excitable optoelectronic devices and in particular excitable semiconductor lasers that could potentially enable unconventional processing approaches beyond conventional binary-logic-based approaches. In parallel, there has been renewed investigation of non-von Neumann architectures driven in part by incipient limitations in aspects of Moore’s law. These neuromorphic architectures attempt to decentralize processing by interweaving interconnection with computing while simultaneously incorporating time-resolved dynamics, loosely classified as spiking (a.k.a. excitability). The rapid and efficient advances in CMOS-compatible photonic interconnect technologies have led to opportunities in optics and photonics for unconventional circuits and systems. Effort in the budding research field of photonic spike processing aims to synergistically integrate the underlying physics of photonics with bio-inspired processing. Lasers operating in the excitable regime are dynamically analogous with the spiking dynamics observed in neuron biophysics but roughly 8 orders of magnitude faster. The field is reaching a critical juncture at which there is a shift from studying single devices to studying an interconnected network of lasers. In this paper, we review the recent research in the information processing abilities of such lasers, dubbed “photonic neurons,” “laser neurons,” or “optical neurons.” An integrated network of such lasers on a chip could potentially grant the capacity for complex, ultrafast categorization and decision making to provide a range of computing and signal processing applications, such as sensing and manipulating the radio frequency spectrum and for hypersonic aircraft control.

Photonic dark matter portal and quantum physics

We study a model of dark matter in which the hidden sector interacts with standard model particles via a hidden photonic portal. We investigate the effects of this new interaction on the hydrogen atom, including the Stark, Zeeman and hyperfine effects. Using the accuracy of the measurement of energy, we obtain an upper bound for the coupling constant of the model as f ⩽ 10−12. We also calculate the contribution from the hidden photonic portal to the anomalous magnetic moment of the muon as aμ ⩽ 2.2 × 10−23 (for the dark particle mass scale 100 MeV), which provides an important probe of physics beyond the standard model.

Results and perspectives in dark photon physics

The introduction of a hidden sector of particles and a new very weak interaction with the fundamental Standard Model fermions could explain the anomalies in the muon magnetic moment, the results from scattering experiments searching for Dark Matter and also the antimatter excess in the cosmic rays. The simplest interaction scenario is an additional U(1) gauge symmetry resembling the electromagnetism but with a massive interaction carrier —the dark photon A′. Such a model has a high predictive power and is being extensively tested by past and present experiments. Present status of the dark photon searches is discussed as well as the possible improvements in the near future.

The AMMON experiment in EOLE zero power facility: a challenging program devoted to the neutron and photon physics

The AMMON integral experiment was carried out in the EOLE critical mock-up at CEA Cadarache. It has been dedicated to the analysis of the Jules Horowitz Reactor (JHR) neutron and photon physics and has a very specific design in comparison with previous cores (MISTRAL, FUBILA, etc.) consisting in the loading of UOX or MOX fuel pins in EOLE. The core configurations consisted of an experimental zone of six or seven JHR-type assemblies with U3Si2–Al 27% 235U enriched curved fuel plates, surrounded by a driver zone with enough standard pressurized water reactor (PWR) UOX fuel pins to reach criticality. Five main configurations have been studied during this three-year ambitious program.The purpose of this paper is to synthesize the main features of this program in terms of experimental methods and associated uncertainties. Almost all the measurements have been analyzed with TRIPOLI-4® Monte Carlo reference calculations, using the JEFF-3.1.1 nuclear data library; this paper gives examples of the analysis of the critical states studied in the experiment as well as the analysis of the isothermal temperature coefficient.

Standard model measurements with ATLAS (+CMS) detector(s)

We present a broad range of Standard Model measurements performed in proton-proton collisions at the LHC on a variety of topics [Formula: see text]jets production and ratios, the electroweak multi-boson production, [Formula: see text] heavy flavor decay production, jet production, photon physics, the Standard Model soft QCD and diffractive physics. The latest public results from ATLAS experiment are obtained at the center-of-mass energy of both 7 TeV and 8 TeV, which covers total cross sections, fiducial cross sections, differential cross sections wherever available and comparison with Leading-Order/Next-to-Leading-Order/Next-to-Next-to-Leading-Order theory predictions. These measurements provide important tests for perturbative QCD, electroweak multi-boson interactions, Electroweak Symmetry Breaking over a broad kinematic range and constraints for PDFs. Model-independent new physics searches are also performed by probing anomalous gauge bosons couplings using effective Lagrangian or effective field theory formalism.

CAD-based Monte Carlo program for integrated simulation of nuclear system SuperMC

Monte Carlo (MC) method has distinct advantages to simulate complicated nuclear systems and is envisioned as a routine method for nuclear design and analysis in the future. High-fidelity simulation with MC method coupled with multi-physics phenomena simulation has significant impact on safety, economy and sustainability of nuclear systems. However, great challenges to current MC methods and codes prevent its application in real engineering projects. SuperMC, developed by the FDS Team in China, is a CAD-based Monte Carlo program for integrated simulation of nuclear systems by making use of hybrid MC and deterministic methods and advanced computer technologies. The design objective, architecture and main methodology of SuperMC are presented in this paper. SuperMC2.1, the latest version, can perform neutron, photon and coupled neutron and photon transport calculation, geometry and physics modeling, results and process visualization. It has been developed and verified by using a series of benchmarking cases such as the fusion reactor ITER model and the fast reactor BN-600 model. SuperMC is still in its evolution process toward a general and routine tool for the simulation of nuclear systems.

Monte Carlo Interpretation of the Photon Heating Measurements in the Integral AMMON/REF Experiment in the EOLE Facility

An experiment named AMMON is dedicated to the analysis of the neutron and photon physics of the Jules Horowitz Reactor (JHR). AMMON, performed in the EOLE zero-power experimental reactor at CEA Cadarache, is finished since April 2013. Photon heating measurements were performed with both Thermoluminescent Dosimeters (TLD-400s) and Optically-Stimulated Dosimeters (OSLDs) in three AMMON configurations. The objective is to provide data for the experimental validation of the JHR photon calculation tool. The first analysis of the photon heating measurements of the reference configuration (AMMON/REF) is presented in this paper. The reference configuration consists of an experimental zone of 7 JHR assemblies with U <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> - Al 27% <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">235</sup> U enriched fuel curved plates surrounded by a driver zone with 623 standard PWR UOx fuel pins. The photon heating has been measured in the aluminum follower of the central and peripheral assemblies, and in aluminum fillers in the rack between assemblies. The measurement analysis is based on Monte Carlo TRIPOLI-4 ® version 8.1 calculations modeling the core exact three-dimensional geometry. The JEFF nuclear data library is used for the calculation of the neutron transport and the photon emission in the AMMON/REF experiment. The photon transport is made on the basis of the EPDL97 photo-atomic library. The prompt and delayed doses deposited in dosimeters have been estimated separately. The transport of 4 (neutrons, photons, electrons and positrons) or 3 particles (photons, electrons and positrons) is simulated in the calculations for the AMMON/REF analysis, depending whether the prompt or delayed dose is calculated. The TRIPOLI-4.8.1 ® calculations makes it possible the modeling of the electromagnetic cascade shower with both electrons and positrons. The delayed dose represents about 25% of the total photon energy deposition in the dosimeters. The comparison between Calculation and Experiment brings into relief a slight systematic underestimation of the calculated global photon energy deposition: (C - E)/E = - 8% ±4.5% (1σ). A special care has been directed towards the determination of the uncertainty associated with the (C-E)/E values. The slight underestimation could be probably explained by an underestimation in the photon emission with the JEFF library.

The “Dynamic Gravitation of Photons: A Hitherto Unknown Physical Quantity”. New Aspects on the Physics of Photons

In order to explore the nature of photons, no doubts can be allowed to exist concerning the “physics of photons”. While static gravitation plays no role in the physics of photons, this paper will show that the previously unknown nonbaryonic dynamic gravitation of photons determines not only the external physical behaviour of photons but also, in particular, the hitherto unknown physical events occurring within the photons themselves. For this reason, the paper places particular emphasis on dynamic gravitation as a new hitherto unknown physical quantity. Moreover the new type of gravitation postulated here also provides a plausible explanation of the mysterious nonbaryonic dark matter. As no generally accepted scientific explanation of the creation and essence of dark matter exists to date, it is to be anticipated that the nonbaryonic dynamic gravitation of photons is of general interest to physicists as well as cosmologists and may serve to initiate a general debate among them. Furthermore, this paper will also show that there exists a close mutual relationship between electrodynamics dynamic gravitation static gravitation electrostatics electrodynamics (refer to paragraph 4). Due to the fact that the insights into the relationship between photons and their dynamic gravitation have not been described by any other author to date, there exists only a few references that I can cite in support of my paper.

Monte Carlo Interpretation of the AMMON/REF Experiment in EOLE for the JHR Reactor Neutron Calculations

A new experimental program, named AMMON, was performed between late 2010 and early 2013 in the EOLE zero-power experimental reactor at CEA Cadarache. It is dedicated to the analysis of the neutron and photon physics of the Jules Horowitz Reactor (JHR), the next international materials testing reactor under construction in France. The objective of the program is to provide measurement data for the experimental validation of the calculation tools developed for the JHR design and safety studies. The first core configuration, the so-called reference configuration, was loaded in 2012; it consisted of an experimental zone of seven JHR assemblies with U3Si2-Al, 27% 235U enriched fuel curved plates surrounded by a driver zone with 622 standard pressurized water reactor uranium oxide fuel pins. It has been instrumented and studied throughout the first year of the experimental program.The final analysis of the AMMON/REF neutron measurements is presented in this paper. It is based on calculations performed with the three-dimensional reference Monte Carlo TRIPOLI-4.7 code and the JEFF3.1.1 European library. The comparison between calculation and experiment makes it possible to calibrate the bias due to nuclear data on the calculated neutron parameters. It highlights good agreement between calculation and experiment concerning reactivity, power distribution in the experimental zone, fuel plate conversion ratios, and core kinetics parameters. The reactivity prediction is very satisfactory, despite the presence of a large aluminum quantity in the core: calculation-to-experiment comparison (C – E) = + 365 ± 334 pcm (1σ). For the other neutron parameters (assembly power distribution, plate conversion ratios, and kinetics parameters), the (C – E)/E discrepancies are within the experimental uncertainty (2σ).

Geant4-based Monte Carlo simulations on GPU for medical applications

Monte Carlo simulation (MCS) plays a key role in medical applications, especially for emission tomography and radiotherapy. However MCS is also associated with long calculation times that prevent its use in routine clinical practice. Recently, graphics processing units (GPU) became in many domains a low cost alternative for the acquisition of high computational power. The objective of this work was to develop an efficient framework for the implementation of MCS on GPU architectures. Geant4 was chosen as the MCS engine given the large variety of physics processes available for targeting different medical imaging and radiotherapy applications. In addition, Geant4 is the MCS engine behind GATE which is actually the most popular medical applications' simulation platform. We propose the definition of a global strategy and associated structures for such a GPU based simulation implementation. Different photon and electron physics effects are resolved on the fly directly on GPU without any approximations with respect to Geant4. Validations have shown equivalence in the underlying photon and electron physics processes between the Geant4 and the GPU codes with a speedup factor of 80–90. More clinically realistic simulations in emission and transmission imaging led to acceleration factors of 400–800 respectively compared to corresponding GATE simulations.

Theoretical Implications on Visual (Color) Representation and Cytochrome Oxidase Blobs

AbstractThe rich concentration of mitochondrial cytochrome oxidase (CO) blobs in the V1 (striate) primate visual cortex has never been explained. Although the distribution of CO blobs provided a persuasive example of columnar structure in the V1, there are contradictions about the existence of hypercolumns. Since photoreceptors and other retinal cells process and convey basically external visible photonic signals, it suggests that one of the most important tasks of early visual areas is to represent these external visible color photonic signals during visual perception. This representation may occur essentially in CO-rich blobs of the V1. Here we suggest that the representation of external visible photon signals (i.e. visual representation) can be the most energetic allocation process in the brain, which is reasonably performed by the highest density neuron al V1 areas and mitochondrial-rich cytochrome oxidases. It is also raised that the functional unit for phosphene induction can be linked to small clusters of Co —rich blobs in V1. We present some implications about distinction between the physics of visible photons/ light and its subjective experiences. We also discuss that amodal and modal visual completions are possible due to the visual perception induced visualization when the brain tries to interpret the unseen parts of objects or represent features of perceived objects that are not actually visible. It is raised that continuously produced intrinsic bioluminescent photons from retinal lipid peroxidation may have functional role in initial development of retinogeniculate pathways as well as initial appearance topographic organizations of V1 before birth. Finally, the metaphysical framework is the extended version of dual-aspect monism (DAMv) that has the least number of problems compared to all other frameworks and hence it is better than the materialism that is currently dominant in science.

Recent photon physics results from the ALICE experiment at the LHC

We present an overview of the photon analysis in pp and Pb-Pb collisions with data taken by the ALICE experiment at the LHC. The ALICE detectors reconstruct photons by using the two electromagnetic calorimeters (photon spectrometer, sampling calorimeter) and central tracking systems for photon converted e + e pairs in the material of the inner ALICE layers. In Pb-Pb collisions the direct photon calculations under- predict the data below 4 GeV/c where it is expected to have a contribution from thermal radiations. The direct photon measurement also shows evidence for a non-zero elliptic flow for 1< pT < 3 GeV/c. The nuclear modi- fication factor of the 0 production at di erent collision centralities shows a clear pattern of strong suppression in a hot QCD medium with respect to pp collisions. Finally, parton fragmentation following hard collisions is investigated by correlating high momentum direct photons and charged hadrons with the goal of revealing new insights into medium e ects in the QGP.

Ultra-Fast Flash Observatory: Fast Response Space Missions for Early Time Phase of Gamma Ray Bursts

One of the unexplored domains in the study of gamma-ray bursts (GRBs) is the early time phase of the optical light curve. We have proposed Ultra-Fast Flash Observatory (UFFO) to address this question through extraordinary opportunities presented by a series of small space missions. The UFFO is equipped with a fast-response Slewing Mirror Telescope that uses a rapidly moving mirror or mirror array to redirect the optical beam rather than slewing the entire spacecraft or telescope to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with sub-second response, for the first time, opening a completely new frontier in GRB and transient studies. Its fast response measurements of the optical emission of dozens of GRB each year will provide unique probes of the burst mechanism and test the prospect of GRB as a new standard candle, potentially opening up the z > 10 universe. We describe the current limit in early photon measurements, the aspects of early photon physics, our soon-to-be-launched UFFO-pathfinder mission, and our next planned mission, the UFFO-100.