A Polynomial Estimate of Railway Line Delay

DEFF Research Database (Denmark)

Cerreto, Fabrizio; Harrod, Steven; Nielsen, Otto Anker

2017-01-01

Railway service may be measured by the aggregate delay over a time horizon or due to an event. Timetables for railway service may dampen aggregate delay by addition of additional process time, either supplement time or buffer time. The evaluation of these variables has previously been performed...... by numerical analysis with simulation. This paper proposes an analytical estimate of aggregate delay with a polynomial form. The function returns the aggregate delay of a railway line resulting from an initial, primary, delay. Analysis of the function demonstrates that there should be a balance between the two...

Development of a non-delay-line constant-fraction discriminator

International Nuclear Information System (INIS)

Yang Tao; Zhao Bo; Zhang Chi

2002-01-01

A Non-Delay-Line Constant-Fraction Discriminator (CFD) timing circuit is introduced. The delay line in the CFD is replaced with a low pass filter in this simplified circuit. The timing resolution of the CFD is better than 150 ps

Split and delay photon correlation spectroscopy with a visible light

International Nuclear Information System (INIS)

Rasch, Marten

2016-04-01

The development and performance of a setup constructed with the aim for the split pulse photon correlation spectroscopy is presented in this thesis. The double pulse time structure is accomplished with help of an Acusto-Optic Modulator (AOM) crystal, which mimics the splitting and delaying of photon pulses. The setup provides double pulses and allows to control the pulse width and delay and to synchronize them into one camera exposure window. The performance of the setup was successfully verified in a proof of principle experiment with a model system of polystyrene particles following Brownian motion. The measured radius of particles obtained with from the split pulse experiment (R h =(2.567±0.097) μm) is in agreement with the particle size provided by the manufacturer (R=(2.26±0.08) μm). The achieved results show higher statistics compared to a standard Dynamic Light Scattering (DLS) measurement.

Regenerative memory in time-delayed neuromorphic photonic resonators

OpenAIRE

Romeira, B.; Avó, R.; Figueiredo, José M. L.; Barland, S.; Javaloyes, J.

2016-01-01

We investigate a photonic regenerative memory based upon a neuromorphic oscillator with a delayed self-feedback (autaptic) connection. We disclose the existence of a unique temporal response characteristic of localized structures enabling an ideal support for bits in an optical buffer memory for storage and reshaping of data information. We link our experimental implementation, based upon a nanoscale nonlinear resonant tunneling diode driving a laser, to the paradigm of neuronal activity, the...

Transmission Delay Modeling of Packet Communication over Digital Subscriber Line

Directory of Open Access Journals (Sweden)

Jiri Vodrazka

2013-01-01

Full Text Available Certain multimedia and voice services, such as VoIP, IPTV, etc., are significantly delay sensitive and their performance is influenced by the overall transmission delay and its variance. One of the most common solutions used in access networks are xDSL lines, especially ADSL2+ or VDSL2. Although these subscriber lines also use packet communication, there are several differences and mechanisms, which influence their resulting delay. Their delay characteristics are also dependent on the individual settings of each xDSL provider, therefore we decided to investigate this area for typical commercially available lines in Czech Republic. Based on the measured values and experiments with real ADSL2+ lines we also developed a potential modeling method, which is presented in this article as well. The parameters for packet jitter based on the generalized Pareto distribution were modeled.

A review on high-resolution CMOS delay lines: towards sub-picosecond jitter performance.

Science.gov (United States)

Abdulrazzaq, Bilal I; Abdul Halin, Izhal; Kawahito, Shoji; Sidek, Roslina M; Shafie, Suhaidi; Yunus, Nurul Amziah Md

2016-01-01

A review on CMOS delay lines with a focus on the most frequently used techniques for high-resolution delay step is presented. The primary types, specifications, delay circuits, and operating principles are presented. The delay circuits reported in this paper are used for delaying digital inputs and clock signals. The most common analog and digitally-controlled delay elements topologies are presented, focusing on the main delay-tuning strategies. IC variables, namely, process, supply voltage, temperature, and noise sources that affect delay resolution through timing jitter are discussed. The design specifications of these delay elements are also discussed and compared for the common delay line circuits. As a result, the main findings of this paper are highlighting and discussing the followings: the most efficient high-resolution delay line techniques, the trade-off challenge found between CMOS delay lines designed using either analog or digitally-controlled delay elements, the trade-off challenge between delay resolution and delay range and the proposed solutions for this challenge, and how CMOS technology scaling can affect the performance of CMOS delay lines. Moreover, the current trends and efforts used in order to generate output delayed signal with low jitter in the sub-picosecond range are presented.

TECHNICAL DESIGN NOTE: Picosecond resolution programmable delay line

Science.gov (United States)

Suchenek, Mariusz

2009-11-01

The note presents implementation of a programmable delay line for digital signals. The tested circuit has a subnanosecond delay range programmable with a resolution of picoseconds. Implementation of the circuit was based on low-cost components, easily available on the market.

Note: Large active area solid state photon counter with 20 ps timing resolution and 60 fs detection delay stability

Science.gov (United States)

Prochazka, Ivan; Kodet, Jan; Eckl, Johann; Blazej, Josef

2017-10-01

We are reporting on the design, construction, and performance of a photon counting detector system, which is based on single photon avalanche diode detector technology. This photon counting device has been optimized for very high timing resolution and stability of its detection delay. The foreseen application of this detector is laser ranging of space objects, laser time transfer ground to space and fundamental metrology. The single photon avalanche diode structure, manufactured on silicon using K14 technology, is used as a sensor. The active area of the sensor is circular with 200 μm diameter. Its photon detection probability exceeds 40% in the wavelength range spanning from 500 to 800 nm. The sensor is operated in active quenching and gating mode. A new control circuit was optimized to maintain high timing resolution and detection delay stability. In connection to this circuit, timing resolution of the detector is reaching 20 ps FWHM. In addition, the temperature change of the detection delay is as low as 70 fs/K. As a result, the detection delay stability of the device is exceptional: expressed in the form of time deviation, detection delay stability of better than 60 fs has been achieved. Considering the large active area aperture of the detector, this is, to our knowledge, the best timing performance reported for a solid state photon counting detector so far.

Topological Acoustic Delay Line

Science.gov (United States)

Zhang, Zhiwang; Tian, Ye; Cheng, Ying; Wei, Qi; Liu, Xiaojun; Christensen, Johan

2018-03-01

Topological protected wave engineering in artificially structured media is at the frontier of ongoing metamaterials research that is inspired by quantum mechanics. Acoustic analogues of electronic topological insulators have recently led to a wealth of new opportunities in manipulating sound propagation with strikingly unconventional acoustic edge modes immune to backscattering. Earlier fabrications of topological insulators are characterized by an unreconfigurable geometry and a very narrow frequency response, which severely hinders the exploration and design of useful devices. Here we establish topologically protected sound in reconfigurable phononic crystals that can be switched on and off simply by rotating its three-legged "atoms" without altering the lattice structure. In particular, we engineer robust phase delay defects that take advantage of the ultrabroadband reflection-free sound propagation. Such topological delay lines serve as a paradigm in compact acoustic devices, interconnects, and electroacoustic integrated circuits.

Magnonic Crystal as a Delay Line for Low-Noise Auto-Oscillator

Science.gov (United States)

2015-05-12

Magnonic crystal as a delay line for low-noise auto-oscillator Elena Bankowski and Thomas Meitzler U.S. Army TARDEC, Warren, Michigan 48397, USA...authors propose to use the magnonic crystal patterned on the YIG magnetic film as an efficient delay line in the feedback loop of tunable auto-oscillator...increasing the thickness of such delay line as compare to the YIG film with no pattern. In turn, use of this magnonic crystal opens a way to improve

Delay estimation on a railway-line with smart use of micro-simulation

DEFF Research Database (Denmark)

Cerreto, Fabrizio; Harrod, Steven; Nielsen, Otto Anker

2017-01-01

This paper formulates a delay propagation model that estimates total railway line delay as a polynomial function of a single primary delay. The estimate is derived from a finite series of delays over a horizon that spans two dimensions: the length of the railway line and the number of trains in t...

New approach to design and performance assessment of delay lines for radioactive rare gases

International Nuclear Information System (INIS)

Wilhelmova, L.; Dvorak, Z.; Cejnar, F.

1981-01-01

The evaluation and analysis are discussed of the dynamic adsorption of rare gases in the delay lines of nuclear power plants. The method of statistical momenta was used for deriving relations for the calculation of penetration curves of radioactive isotopes of rare gases through a delay line. Relations were also derived for the calculation of the capacity of delay line adsorption beds for both continuous and discontinuous operation. The procedures for the design and the derivation of the function of delay lines take into account the actual conditions of delay line operation in nuclear power plants. (author)

Source of single photons and interferometry with one photon. From the Young's slit experiment to the delayed choice

International Nuclear Information System (INIS)

Jacques, V.

2007-11-01

This manuscript is divided in two independent parts. In the first part, we study the wave-particle duality for a single photon emitted by the triggered photoluminescence of a single NV color center in a diamond nano-crystal. We first present the realization of a single-photon interference experiment using a Fresnel's bi-prism, in a scheme equivalent to the standard Young's double-slit textbook experiment. We then discuss the complementarity between interference and which-path information in this two-path interferometer. We finally describe the experimental realization of Wheeler's delayed-choice Gedanken experiment, which is a fascinating and subtle illustration of wave-particle duality. The second part of the manuscript is devoted to the efficiency improvement of single-photon sources. We first describe the implementation of a new single-photon source based on the photoluminescence of a single nickel-related defect center in diamond. The photophysical properties of such defect make this single-photon source well adapted to open-air quantum cryptography. We finally demonstrate an original method that leads to an improvement of single-molecule photo stability at room temperature. (author)

A new delay line loops shrinking time-to-digital converter in low-cost FPGA

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jie, E-mail: zhangjie071063@163.com [State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, CAS, Wuhan, China, 430077 (China); University of Chinese Academy of Sciences, Beijing, China, 100049 (China); Zhou, Dongming [State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, CAS, Wuhan, China, 430077 (China)

2015-01-21

The article provides the design and test results of a new time-to-digital converter (TDC) based on delay line loops shrinking method and implemented in a low-cost field programmable gate array (FPGA) device. A technique that achieves high resolution with low cost and flexibility is presented. The technique is based on two delay line loops which are used to directly shrink the measured time interval in the designed TDC, and the resolution is dependent on the difference between the entire delay times of the two delay line loops. In order to realize high resolution and eliminate temperature influence, the two delay line loops consist of the same delay cells with the same number. A delay-locked loop (DLL) is used to stabilize the resolution against process variations and ambient conditions. Meanwhile, one method is used to accurately evaluate the resolution of the implemented TDC. The converter has been implemented in a general-propose FPGA device (Actel SmartFusion A2F200M3). A single shot resolution of the implemented converter is 63.3 ps and the measurement standard deviation is about 61.7 ps within the measurement range of 5 ns. - Highlights: • We provide a new FPGA-integrated time-to-digital converter based on delay line loops method which used two delay line loops to directly shrink time intervals with only rising edges. • The two delay line loops consist of the same delay cells with the same number and symmetrical structure. • The resolution is dependent on the difference between the entire delays of the two delay line loops. • We use delay-locked loop to stabilize the resolution against temperature and supply voltage.

A new delay line loops shrinking time-to-digital converter in low-cost FPGA

International Nuclear Information System (INIS)

Zhang, Jie; Zhou, Dongming

2015-01-01

The article provides the design and test results of a new time-to-digital converter (TDC) based on delay line loops shrinking method and implemented in a low-cost field programmable gate array (FPGA) device. A technique that achieves high resolution with low cost and flexibility is presented. The technique is based on two delay line loops which are used to directly shrink the measured time interval in the designed TDC, and the resolution is dependent on the difference between the entire delay times of the two delay line loops. In order to realize high resolution and eliminate temperature influence, the two delay line loops consist of the same delay cells with the same number. A delay-locked loop (DLL) is used to stabilize the resolution against process variations and ambient conditions. Meanwhile, one method is used to accurately evaluate the resolution of the implemented TDC. The converter has been implemented in a general-propose FPGA device (Actel SmartFusion A2F200M3). A single shot resolution of the implemented converter is 63.3 ps and the measurement standard deviation is about 61.7 ps within the measurement range of 5 ns. - Highlights: • We provide a new FPGA-integrated time-to-digital converter based on delay line loops method which used two delay line loops to directly shrink time intervals with only rising edges. • The two delay line loops consist of the same delay cells with the same number and symmetrical structure. • The resolution is dependent on the difference between the entire delays of the two delay line loops. • We use delay-locked loop to stabilize the resolution against temperature and supply voltage

Two-dimensional topological photonics

Science.gov (United States)

Khanikaev, Alexander B.; Shvets, Gennady

2017-12-01

Originating from the studies of two-dimensional condensed-matter states, the concept of topological order has recently been expanded to other fields of physics and engineering, particularly optics and photonics. Topological photonic structures have already overturned some of the traditional views on wave propagation and manipulation. The application of topological concepts to guided wave propagation has enabled novel photonic devices, such as reflection-free sharply bent waveguides, robust delay lines, spin-polarized switches and non-reciprocal devices. Discrete degrees of freedom, widely used in condensed-matter physics, such as spin and valley, are now entering the realm of photonics. In this Review, we summarize the latest advances in this highly dynamic field, with special emphasis on the experimental work on two-dimensional photonic topological structures.

A current controlled variable delay superconducting transmission line

International Nuclear Information System (INIS)

Anlage, S.M.; Snortland, H.J.; Beasley, M.R.

1989-01-01

The authors present a device concept for a current-controlled variable delay for superconducting transmission line. The device makes use of the change in kinetic inductance of a superconducting transmission line under the application of a DC bias current. The relevant materials parameters and several promising superconducting materials have been identified

A monolithic constant-fraction discriminator using distributed R-C delay-line shaping

International Nuclear Information System (INIS)

Simpson, M.L.; Young, G.R.; Xu, M.

1995-01-01

A monolithic, CMOS, constant-fraction discriminator (CFD) was fabricated in the Orbit Semiconductor, 1.2 μ N-well process. This circuit uses an on-chip, distributed, R-C delay-line to realize the constant-fraction shaping. The delay-line is constructed from a narrow, 500-μ serpentine layer of polysilicon above a wide, grounded, second layer of polysilicon. This R-C delay-line generates about 1.1 ns of delay for 5 ns risetime signals with a slope degradation of only ≅ 15% and an amplitude reduction of about 6.1%. The CFD also features an automatic walk adjustment. The entire circuit, including the delay line, has a 200 μ pitch and is 950 μ long. The walk for a 5 ns risetime signal was measured as ± 100 ps over the 100:1 dynamic range from -15 mV to -1.5 mV. to -1.5 V. The CFD consumes 15 mW

Multimoded rf delay line distribution system for the Next Linear Collider

Directory of Open Access Journals (Sweden)

S. G. Tantawi

2002-03-01

Full Text Available The delay line distribution system is an alternative to conventional pulse compression, which enhances the peak power of rf sources while matching the long pulse of those sources to the shorter filling time of accelerator structures. We present an implementation of this scheme that combines pairs of parallel delay lines of the system into single lines. The power of several sources is combined into a single waveguide delay line using a multimode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted from the delay line using mode-selective extractors, each of which extracts a single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the Next Linear Collider design while maintaining high efficiency.

Assembly delay line pulse generators

CERN Multimedia

CERN PhotoLab

1971-01-01

Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

Radiofrequency spark chambers and delay line resonators

International Nuclear Information System (INIS)

Sayag, Jacques

1971-01-01

According to a suggestion of A. Kastler, a spark chamber was excited by an undamped radiofrequency pulse and tracks about 1 mm wide obtained; the result was interpreted by computation of the coefficients of electronic amplification and partial ambipolar diffusion. This work led us to the construction of a new fast triggering undamped wave-train generator of very high tension (patent taken out by the C.E.A. under the no.: EN 7 134 650 the 27.9.1971). Since this apparatus uses a resonant storage line, its design implied a precise knowledge of high impedance delay lines. The experimental radiofrequency spectra of the input impedance of opened or short-circuited lines were plotted completely and analysed by the circuits theory, new measuring methods were established, dispersion relations accurately checked and the equivalence of the formulas, within the third order, with theses of Debye's Dipolar Absorption demonstrated. General properties of Hilbert's transform were also investigated. From the experimental point of view, the electromagnetic energy storage process was extended to the case of a liquid nitrogen-immersed resonant delay line. The good behavior of the cryogenic experiment, where the main difficulty of icing was overcame by the construction of special electrodes, offers great promise for extrapolation to superconductivity. (author) [fr

Mixed Modeling of a SAW Delay Line Using VHDL-AMS

Science.gov (United States)

Wilson, William C.; Atkinson, Gary M.

2006-01-01

To aid in the development of SAW sensors for aerospace applications we have created a model of a SAW Delay line using VHDL. The model implements the Impulse Response method to calculate the frequency response, impedance, and insertion loss. The model includes optimization for the number of finger pairs in the IDTs and for the aperture height. This paper presents the model and the results from the model for a SAW delay line design.

A scheme to expand the delay-bandwidth product in the resonator-based delay lines by optical OFDM technique

DEFF Research Database (Denmark)

Zhu, Jiangbo; Tao, Li; Zhang, Ziran

2013-01-01

We propose a novel scheme to expand the inherent limit in the product of the optical delay and the transmission bandwidth in resonator-based delay lines, with the optical orthogonal frequency division multiplexing (OOFDM) technique. The optical group delay properties of a single ring resonator we...

High-explosive-driven delay line pulse generator

International Nuclear Information System (INIS)

Shearer, J.W.

1982-01-01

The inclusion of a delay line circuit into the design of a high-explosive-driven generator shortens the time constant of the output pulse. After a brief review of generator concepts and previously described pulse-shortening methods, a geometry is presented which incorporates delay line circuit techcniques into a coil generator. The circuit constants are adjusted to match the velocity of the generated electromagnetic wave to the detonation velocity of the high explosive. The proposed generator can be modeled by adding a variable inductance term to the telegrapher's equation. A particular solution of this equation is useful for exploring the operational parameters of the generator. The duration of the electromagnetic pulse equals the radial expansion time of the high-explosive-driven armature until it strikes the coil. Because the impedance of the generator is a constant, the current multiplication factor is limited only by nonlinear effects such as voltage breakdown, diffusion, and compression at high energies

Electromagnetic energy flow lines as possible paths of photons

Energy Technology Data Exchange (ETDEWEB)

Davidovic, M [Faculty of Civil Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia); Sanz, A S; Miret-Artes, S [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones CientIficas, Serrano 123, 28006 Madrid (Spain); Arsenovic, D; Bozic, M [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)], E-mail: milena@grf.bg.ac.yu, E-mail: asanz@imaff.cfmac.csic.es, E-mail: arsenovic@phy.bg.ac.yu, E-mail: bozic@phy.bg.ac.yu, E-mail: s.miret@imaff.cfmac.csic.es

2009-07-15

Motivated by recent experiments where interference patterns behind a grating are obtained by accumulating single photon events, we provide here an electromagnetic energy flow-line description to explain the emergence of such patterns. We find and discuss an analogy between the equation describing these energy flow lines and the equation of Bohmian trajectories used to describe the motion of massive particles.

Delays in switching patients onto second-line antiretroviral treatment ...

African Journals Online (AJOL)

Background: South Africa has one of the largest antiretroviral treatment (ART) programmes globally. In addition to increasing access to ART, it is important that the health system also focuses on the appropriate management of patients who fail first-line ART. Delays in switching patients onto second-line ART can adversely ...

Estimating Angle of Arrival (AOA for Wideband Signal by Sensor Delay Line (SDL and Tapped Delay Line (TDL Processors

Directory of Open Access Journals (Sweden)

Bassim Sayed Mohammed

2018-04-01

Full Text Available Angle of arrival (AOA estimation for wideband signal becomes more necessary for modern communication systems like Global System for Mobile (GSM, satellite, military applications and spread spectrum (frequency hopping and direct sequence. Most of the researchers are focusing on how to cancel the effects of signal bandwidth on AOA estimation performance by using a transversal filter (tap delay line (TDL. Most of the researchers were using two elements array antenna to study these effects. In this research, a general case of proposed (M array elements is used. A transversal filter (TDL in phase adaptive array antenna system is used to calculate the optimum number of taps required to compensate these effect. The proposed system uses a phase adaptive array antenna in conjunction with LMS algorithm to work an angle of arrival (AOA estimator for wideband signals rather than interference canceller. An alternative solution to compensate for the effect of signal bandwidth is proposed by using sensor delay line (SDL instead of fixed delay unit since it has variable time sampling in the time domain and not fixed time delay, depending on the angle of arrival of received signals. The proposed system has the ability to estimate two parameters for received signals simultaneously (the output Signal to Noise Ratio (SNR and AOA, unlike others systems which estimate AOA only. The comparison of the simulation results with Multiple Signal Classification (MUSIC technique showed that the proposed system gives good results for estimating AOA and the output SNR for wideband signals. (SDL processor shows better performance result than (TDL processor. MUSIC technique with both (SDL and (TDL processors shows unacceptable results for estimating (AOA for the wideband signal.

Thermally activated delayed fluorescence organic dots for two-photon fluorescence lifetime imaging

Science.gov (United States)

He, Tingchao; Ren, Can; Li, Zhuohua; Xiao, Shuyu; Li, Junzi; Lin, Xiaodong; Ye, Chuanxiang; Zhang, Junmin; Guo, Lihong; Hu, Wenbo; Chen, Rui

2018-05-01

Autofluorescence is a major challenge in complex tissue imaging when molecules present in the biological tissue compete with the fluorophore. This issue may be resolved by designing organic molecules with long fluorescence lifetimes. The present work reports the two-photon absorption (TPA) properties of a thermally activated delayed fluorescence (TADF) molecule with carbazole as the electron donor and dicyanobenzene as the electron acceptor (i.e., 4CzIPN). The results indicate that 4CzIPN exhibits a moderate TPA cross-section (˜9 × 10-50 cm4 s photon-1), high fluorescence quantum yield, and a long fluorescence lifetime (˜1.47 μs). 4CzIPN was compactly encapsulated into an amphiphilic copolymer via nanoprecipitation to achieve water-soluble organic dots. Interestingly, 4CzIPN organic dots have been utilized in applications involving two-photon fluorescence lifetime imaging (FLIM). Our work aptly demonstrates that TADF molecules are promising candidates of nonlinear optical probes for developing next-generation multiphoton FLIM applications.

Superconducting delay lines and chirp filters

International Nuclear Information System (INIS)

Hoefer, G.J.; Kratz, H.A.

1993-01-01

High temperature superconductor (HTSC) thin films are now good enough to realize certain devices, particularly passive analog broadband devices requiring only a single layer of high quality material. This is especially true for long delay lines and related structures, e. g. chirp filters, where low loss and dispersion result in large usable bandwidths. The availability of these devices may hasten the commercialization of the high temperature superconductors, because they take full advantage of their unique properties. (orig.)

A digital TDC with a reduced number of delay line cells

International Nuclear Information System (INIS)

Boujrad, A.; Bloyet, D.; Tripon, M.

2002-01-01

In nuclear physics experiments, a decision maker named as 'trigger' gives a bit pattern which allows the fired detectors identification. As the data acquisition dead time is greater than the time between physical events, timing information is essential. We add to the trigger function a Time to Digital Converter (TDC) in order to make a separation between events. The paper describes the architecture chosen for the TDC and illustrates the contribution of each element to the TDC performance. An eight-bit counter is used for the dynamic range of the TDC (in microsecond) associated to a delay line improving the resolution (in nanosecond). The study shows that exploiting the two system clock states (high and low) allows to reduce the number of delay line cells. The Differential Nonlinearity Measurements are given for different resolutions (1, 2 and 5 ns) and illustrate the clock period, the clock duty cycle and the delay line contributions to the TDC performances

Micromachined silicon acoustic delay line with improved structural stability and acoustic directivity for real-time photoacoustic tomography

Science.gov (United States)

Cho, Young; Kumar, Akhil; Xu, Song; Zou, Jun

2017-03-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. However, as its length increases to provide longer delay time, the delay line becomes more vulnerable to structural instability due to reduced mechanical stiffness. In addition, the small cross-section area of the delay line results in a large acoustic acceptance angle and therefore poor directivity. To address these two issues, this paper reports the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, a new tapered design for the input terminal of the delay line was also investigate to improve its acoustic directivity by reducing the acoustic acceptance angle. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

Several key issues on implementing delay line based TDCs using FPGAs

International Nuclear Information System (INIS)

Wu, Jinyuan

2009-01-01

Several topics in FPGA delay line based TDCs are discussed in this document. First, FPGA specific issues such as considerations on the delay line choice in different FPGA families, Wave Union Launchers, 'bubble proof' encoding logic, etc. are examined. Next, common problems for both FPGA TDCs and ASIC TDCs such as schemes of coarse time counter implementation, bin-by-bin calibration and noise issues due to single ended signals are discussed. Several resource/power saving design approaches for various processing stages are described in the document.

Integrated optical delay lines for time-division multiplexers

NARCIS (Netherlands)

Stopinski, S.T.; Malinowski, M.; Piramidowicz, R.; Kleijn, E.; Smit, M.K.; Leijtens, X.J.M.

2013-01-01

In this paper, we present a study of integrated optical delay lines (DLs) for application in optical time-division multiplexers. The investigated DLs are formed by spirally folded waveguides. The components were designed in a generic approach and fabricated in multi-project wafer runs on an

Optical True Time Delay for Phased Array Antennas Composed of 2×2 Optical MEMS Switches and Fiber Delay Lines

Institute of Scientific and Technical Information of China (English)

Back-Song; Lee; Jong-Dug; Shin; Boo-Gyoun; Kim

2003-01-01

We proposed an optical true time delay (TTD) for phased array antennas (PAAs) composed of 2×2 optical MEMS switches, single-mode fiber delay lines, and a fixed wavelength laser diode. A 3-bit TTD for 10 GHz PAAs was implemented with a time delay error less than ± 0.2 ps.

New β-delayed proton lines from 23Al

DEFF Research Database (Denmark)

Kirsebom, Oliver Sølund; Fynbo, H.; Jokinen, A.

2011-01-01

We report on a new measurement of the β -delayed proton spectrum of 23 Al. Higher statistics compared to previous measurements allow us to identify new proton lines in the energy range 1--2 MeV. A statistical analysis of the observed β strength shows that the B (GT) values are fully consistent...

Coexistence of full which-path information and interference in Wheeler's delayed-choice experiment with photons

NARCIS (Netherlands)

Michielsen, K.; Yuan, S.; Zhao, S.; Jin, F.; De Raedt, H.

We present a computer simulation model that is a one-to-one copy of an experimental realization of Wheeler's delayed-choice experiment that employs a single photon source and a Mach-Zehnder interferometer composed of a 50/50 input beam splitter and a variable output beam splitter with adjustable

Delay-Line Three-Dimensional Position Sensitive Radiation Detection

Science.gov (United States)

Jeong, Manhee

High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR

Active high-power RF pulse compression using optically switched resonant delay lines

International Nuclear Information System (INIS)

Tantawi, S.G.; Ruth, R.D.; Vlieks, A.E.

1996-11-01

The authors present the design and a proof of principle experimental results of an optically controlled high power rf pulse compression system. The design should, in principle, handle few hundreds of Megawatts of power at X-band. The system is based on the switched resonant delay line theory. It employs resonant delay lines as a means of storing rf energy. The coupling to the lines is optimized for maximum energy storage during the charging phase. To discharge the lines, a high power microwave switch increases the coupling to the lines just before the start of the output pulse. The high power microwave switch, required for this system, is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE 01 mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability

Design and commissioning of the photon monitors and optical transport lines for the advanced photon source positron accumulator ring

International Nuclear Information System (INIS)

Berg, W.; Yang, B.; Lumpkin, A.; Jones, J.

1996-01-01

Two photon monitors have been designed and installed in the positron accumulator ring (PAR) of the Advanced Photon Source. The photon monitors characterize the beam's transverse profile, bunch length, emittance, and energy spread in a nonintrusive manner. An optical transport line delivers synchrotron light from the PAR out of a high radiation environment. Both charge-coupled device and fast-gated, intensified cameras are used to measure the transverse beam profile (0.11 - 1 mm for damped beam) with a resolution of 0.06 mm. A streak camera (θ τ =I ps) is used to measure the bunch length which is in the range of 0.3-1 ns. The design of the various transport components and commissioning results of the photon monitors will be discussed

Experimental demonstration of two methods for controlling the group delay in a system with photonic-crystal resonators coupled to a waveguide.

Science.gov (United States)

Huo, Yijie; Sandhu, Sunil; Pan, Jun; Stuhrmann, Norbert; Povinelli, Michelle L; Kahn, Joseph M; Harris, James S; Fejer, Martin M; Fan, Shanhui

2011-04-15

We measure the group delay in an on-chip photonic-crystal device with two resonators side coupled to a waveguide. We demonstrate that such a group delay can be controlled by tuning either the propagation phase of the waveguide or the frequency of the resonators.

Measuring a Fiber-Optic Delay Line Using a Mode-Locked Laser

Science.gov (United States)

Tu, Meirong; McKee, Michael R.; Pak, Kyung S.; Yu, Nan

2010-01-01

The figure schematically depicts a laboratory setup for determining the optical length of a fiber-optic delay line at a precision greater than that obtainable by use of optical time-domain reflectometry or of mechanical measurement of length during the delay-line-winding process. In this setup, the delay line becomes part of the resonant optical cavity that governs the frequency of oscillation of a mode-locked laser. The length can then be determined from frequency-domain measurements, as described below. The laboratory setup is basically an all-fiber ring laser in which the delay line constitutes part of the ring. Another part of the ring - the laser gain medium - is an erbium-doped fiber amplifier pumped by a diode laser at a wavelength of 980 nm. The loop also includes an optical isolator, two polarization controllers, and a polarizing beam splitter. The optical isolator enforces unidirectional lasing. The polarization beam splitter allows light in only one polarization mode to pass through the ring; light in the orthogonal polarization mode is rejected from the ring and utilized as a diagnostic output, which is fed to an optical spectrum analyzer and a photodetector. The photodetector output is fed to a radio-frequency spectrum analyzer and an oscilloscope. The fiber ring laser can generate continuous-wave radiation in non-mode-locked operation or ultrashort optical pulses in mode-locked operation. The mode-locked operation exhibited by this ring is said to be passive in the sense that no electro-optical modulator or other active optical component is used to achieve it. Passive mode locking is achieved by exploiting optical nonlinearity of passive components in such a manner as to obtain ultra-short optical pulses. In this setup, the particular nonlinear optical property exploited to achieve passive mode locking is nonlinear polarization rotation. This or any ring laser can support oscillation in multiple modes as long as sufficient gain is present to overcome

ESO and Fokker Space Sign Contract about VLTI Delay Line

Science.gov (United States)

1998-03-01

The European Southern Observatory is building the world's largest optical telescope, the Very Large Telescope (VLT) , at the ESO Paranal Observatory in Chile. The VLT consists of four 8.2-m unit telescopes and several smaller, moveable Auxiliary Telescopes. When coupled as the giant VLT Interferometer (VLTI) , they will together provide the sharpest images ever obtained by any optical telescope. It will in principle be able to see an astronaut on the surface of the Moon, 400,000 km away. The VLTI Delay Lines Fokker Space (Leiden, The Netherlands) has been awarded a contract for the delivery of the Delay Line of the VLTI. This is a mechanical-optical system that will compensate the optical path differences of the light beams from the individual telescopes. Such a system is necessary to ensure that the light from all telescopes arrive in the same phase at the focal point of the interferometer. Otherwise, the very sharp interferometric images cannot be obtained. ESO PR Photo 08/98 [JPEG, 102k] Schematic representation of the VLTI Delay Line, showing the retro-reflector on its moving base. For more details, please consult the technical explanation below. This highly accurate system will be developed in close co-operation with the Dutch institute TNO-TPD (Netherlands Organization for Applied Scientific Research - Institute of Applied Physics) . The most innovative feature of the Delay Line is the new control strategy, a two-stage control system, based on linear motor technology, combined with high accuracy piezo-electric control elements. This enables the system to position the so-called cat's eye reflector system with an accuracy of only a few nanometers (millionth of a millimetre (nm)) over a stroke length of 60 metres. Within radio astronomy, interferometric techniques have been applied by Dutch astronomers since many years. They will now be able to contribute with their extensive knowledge of such systems to the next generation of astronomical interferometric

An EXAFS spectrometer on beam line 10B at the Photon Factory

International Nuclear Information System (INIS)

Oyanagi, Hiroyuki; Matsushita, Tadashi; Ito, Masahisa; Kuroda, Haruo.

1984-03-01

An EXAFS spectrometer installed on the beam line 10B at the Photon Factory is designed to cover the photon energy between 4 and 30 keV. Utilizing either a channel-cut or two flat silicon crystals as a monochromator, a beam intensity between 10 8 and 10 9 photons/sec is obtained at 9 keV with a resolution of 1 eV. The performance of the spectrometer, such as a signal-to-noise ratio or an energy resolution is demonstrated with examples of K edge absorption spectra of bromine, germanium, gallium arsenide, and zinc selenide. (author)

Generation of narrow-band polarization-entangled photon pairs at a rubidium D1 line

International Nuclear Information System (INIS)

Tian Long; Li Shujing; Yuan Haoxiang; Wang Hai

2016-01-01

Using the process of cavity-enhanced spontaneous parametric down-conversion (SPDC), we generate a narrow-band polarization-entangled photon pair resonant on the rubidium (Rb) D1 line (795 nm). The degenerate single-mode photon pair is selected by multiple temperature controlled etalons. The linewidth of generated polarization-entangled photon pairs is 15 MHz which matches the typical atomic memory bandwidth. The measured Bell parameter for the polarization-entangled photons S = 2.73 ± 0.04 which violates the Bell-CHSH inequality by ∼18 standard deviations. The presented entangled photon pair source could be utilized in quantum communication and quantum computing based on quantum memories in atomic ensemble. (author)

Slow light in a semiconductor waveguide for true-time delay applications in microwave photonics

DEFF Research Database (Denmark)

Öhman, Filip; Yvind, Kresten; Mørk, Jesper

2007-01-01

We have investigated the slowand fast light properties of a semiconductor waveguide device employing concatenated gain and absorber sections. This letter presents the experimental results as well as theoretical modeling. A large phase shift of 110 and a true-time delay of more than 150 ps are dem...... are demonstrated. The combination of amplitude and phase control of the modulated signal shows great promise for applications within microwave photonics....

Antigravity Acts on Photons

Science.gov (United States)

Brynjolfsson, Ari

2002-04-01

Einstein's general theory of relativity assumes that photons don't change frequency as they move from Sun to Earth. This assumption is correct in classical physics. All experiments proving the general relativity are in the domain of classical physics. This include the tests by Pound et al. of the gravitational redshift of 14.4 keV photons; the rocket experiments by Vessot et al.; the Galileo solar redshift experiments by Krisher et al.; the gravitational deflection of light experiments by Riveros and Vucetich; and delay of echoes of radar signals passing close to Sun as observed by Shapiro et al. Bohr's correspondence principle assures that quantum mechanical theory of general relativity agrees with Einstein's classical theory when frequency and gravitational field gradient approach zero, or when photons cannot interact with the gravitational field. When we treat photons as quantum mechanical particles; we find that gravitational force on photons is reversed (antigravity). This modified theory contradicts the equivalence principle, but is consistent with all experiments. Solar lines and distant stars are redshifted in accordance with author's plasma redshift theory. These changes result in a beautiful consistent cosmology.

Real-time pulse deinterleaving using digital delay line techniques

Science.gov (United States)

Lentz, L. F.; Palermo, T. J.

This paper describes an implementation of a tracking pulse sorter based on predictive gating techniques. Real-time pulse sorters or pulse train gating devices have been utilized by the ELINT signal analyst for many years. The more elementary of these devices employed a retriggerable delay interval and an acceptance gate, which were used in predictive fashion to track pulse trains whose PRIs fall within the limits of the programmed delay interval. This design utilizes the pulse hit/miss history of individual track files in a variation of a sequential observer detection algorithm. Use of a digital delay line with pulse history allows multiple pulse trains to be tracked simultaneously and independently without interference. The design also provides flexibility in lock-on and track criteria to allow maintenance of acquisition probability and false alarm rate in dense signal environments and with low SNRs. The hardware provides time interval resolution to 12.5 nsec and covers a PRI range of 50 microsec to 50 msec.

LHCb: Radiation hard programmable delay line for LHCb Calorimeter Upgrade

CERN Multimedia

Mauricio Ferre, J; Vilasís Cardona, X; Picatoste Olloqui, E; Machefert, F; Lefrançois, J; Duarte, O

2013-01-01

This poster describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with a 4ps jitter and 18ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35um technology.

New β-delayed proton lines from 23Al

International Nuclear Information System (INIS)

Kirsebom, O.S.; Fynbo, H.O.U.; Riisager, K.; Jokinen, A.; Saastamoinen, A.; Aeystoe, J.; Madurga, M.; Tengblad, O.

2011-01-01

We report on a new measurement of the β-delayed proton spectrum of 23 Al. Higher statistics compared to previous measurements allow us to identify new proton lines in the energy range 1-2 MeV. A statistical analysis of the observed β strength shows that the B (GT) values are fully consistent with having a Porter-Thomas distribution. This is indicative of chaotic behaviour and implies that only the average β strength carries physical meaning. (orig.)

Microcomb-Based True-Time-Delay Network for Microwave Beamforming With Arbitrary Beam Pattern Control

Science.gov (United States)

Xue, Xiaoxiao; Xuan, Yi; Bao, Chengying; Li, Shangyuan; Zheng, Xiaoping; Zhou, Bingkun; Qi, Minghao; Weiner, Andrew M.

2018-06-01

Microwave phased array antennas (PAAs) are very attractive to defense applications and high-speed wireless communications for their abilities of fast beam scanning and complex beam pattern control. However, traditional PAAs based on phase shifters suffer from the beam-squint problem and have limited bandwidths. True-time-delay (TTD) beamforming based on low-loss photonic delay lines can solve this problem. But it is still quite challenging to build large-scale photonic TTD beamformers due to their high hardware complexity. In this paper, we demonstrate a photonic TTD beamforming network based on a miniature microresonator frequency comb (microcomb) source and dispersive time delay. A method incorporating optical phase modulation and programmable spectral shaping is proposed for positive and negative apodization weighting to achieve arbitrary microwave beam pattern control. The experimentally demonstrated TTD beamforming network can support a PAA with 21 elements. The microwave frequency range is $\\mathbf{8\\sim20\\ {GHz}}$, and the beam scanning range is $\\mathbf{\\pm 60.2^\\circ}$. Detailed measurements of the microwave amplitudes and phases are performed. The beamforming performances of Gaussian, rectangular beams and beam notch steering are evaluated through simulations by assuming a uniform radiating antenna array. The scheme can potentially support larger PAAs with hundreds of elements by increasing the number of comb lines with broadband microcomb generation.

Holographic Fabrication of Designed Functional Defect Lines in Photonic Crystal Lattice Using a Spatial Light Modulator

Directory of Open Access Journals (Sweden)

Jeffrey Lutkenhaus

2016-04-01

Full Text Available We report the holographic fabrication of designed defect lines in photonic crystal lattices through phase engineering using a spatial light modulator (SLM. The diffracted beams from the SLM not only carry the defect’s content but also the defect related phase-shifting information. The phase-shifting induced lattice shifting in photonic lattices around the defects in three-beam interference is less than the one produced by five-beam interference due to the alternating shifting in lattice in three beam interference. By designing the defect line at a 45 degree orientation and using three-beam interference, the defect orientation can be aligned with the background photonic lattice, and the shifting is only in one side of the defect line, in agreement with the theory. Finally, a new design for the integration of functional defect lines in a background phase pattern reduces the relative phase shift of the defect and utilizes the different diffraction efficiency between the defect line and background phase pattern. We demonstrate that the desired and functional defect lattice can be registered into the background lattice through the direct imaging of designed phase patterns.

THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS

International Nuclear Information System (INIS)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C.; Horne, Keith; Bentz, M. C.; Denney, K. D.; Siverd, R.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.

2013-01-01

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the Hβ emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II λ4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

2013-02-10

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

Science.gov (United States)

Cho, Y.; Chang, C.-C.; Wang, L. V.; Zou, J.

2016-02-01

This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT.

Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

International Nuclear Information System (INIS)

Cho, Y; Chang, C-C; Zou, J; Wang, L V

2016-01-01

This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT. (paper)

Micromachined silicon acoustic delay line with 3D-printed micro linkers and tapered input for improved structural stability and acoustic directivity

International Nuclear Information System (INIS)

Cho, Y; Kumar, A; Xu, S; Zou, J

2016-01-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. To achieve deeper imaging depth and wider field of view, a longer delay time and therefore delay length are required. However, as the length of the delay line increases, it becomes more vulnerable to structural instability due to reduced mechanical stiffness. In this paper, we report the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, the improvement of the acoustic acceptance angle of the silicon acoustic delay lines was also investigated to better suppress the reception of unwanted ultrasound signals outside of the imaging plane. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays. (paper)

Optical resonators for true-time-delay beam steering

Science.gov (United States)

Gesell, Leslie H.; Evanko, Stephen M.

1996-06-01

Conventional true time delay beamforming and steering devices rely on switching between various lengths of delay line. Therefore only discrete delays are possible. Proposed is a new photonics concept for true time delay beamforming which provides a finely controlled continuum of delays with switching speeds on the order of 10's of nanoseconds or faster. The architecture uses an array of waveguide cavities with different resonate frequencies to channelize the signal. Each spectral component of the signal is phase shifted by an amount proportional to the frequency of that component and the desired time delay. These phase shifted spectral components are then summed to obtain the delayed signal. This paper provides an overview of the results of a Phase I SBIR contract where this concept has been refined and analyzed. The parameters for an operational system are determined and indication of the feasibility of this approach is given. Among the issues addressed are the requirements of the resonators and the methods necessary to implement fiber optic Bragg gratings as these resonators.

The FERMI-Elettra FEL Photon Transport System

International Nuclear Information System (INIS)

Zangrando, M.; Cudin, I.; Fava, C.; Godnig, R.; Kiskinova, M.; Masciovecchio, C.; Parmigiani, F.; Rumiz, L.; Svetina, C.; Turchet, A.; Cocco, D.

2010-01-01

The FERMI-Elettra free electron laser (FEL) user facility is under construction at Sincrotrone Trieste (Italy), and it will be operative in late 2010. It is based on a seeded scheme providing an almost perfect transform-limited and fully spatially coherent photon beam. FERMI-Elettra will cover the wavelength range 100 to 3 nm with the fundamental harmonics, and down to 1 nm with higher harmonics. We present the layout of the photon beam transport system that includes: the first common part providing on-line and shot-to-shot beam diagnostics, called PADReS (Photon Analysis Delivery and Reduction System), and 3 independent beamlines feeding the experimental stations. Particular emphasis is given to the solutions adopted to preserve the wavefront, and to avoid damage on the different optical elements. Peculiar FEL devices, not common in the Synchrotron Radiation facilities, are described in more detail, e.g. the online photon energy spectrometer measuring shot-by-shot the spectrum of the emitted radiation, the beam splitting and delay line system dedicated to cross/auto correlation and pump-probe experiments, and the wavefront preserving active optics adapting the shape and size of the focused spot to meet the needs of the different experiments.

Thermal analysis of line-defect photonic crystal lasers

DEFF Research Database (Denmark)

Xue, Weiqi; Ottaviano, Luisa; Chen, Yaohui

2015-01-01

under CW optical pumping, whereas InGaAsP membranes only lase under pulsed conditions. By varying the duty cycle of the pump beam, we quantify the heating induced by optical pumping in the two material platforms and compare their thermal properties. Full 3D finite element simulations show the spatial......We report a systematic study of thermal effects in photonic crystal membrane lasers based on line-defect cavities. Two material platforms, InGaAsP and InP, are investigated experimentally and numerically. Lasers with quantum dot layers embedded in an InP membrane exhibit lasing at room temperature...

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

Science.gov (United States)

Li, Guang-Hui; Wang, An-Bang; Feng, Ye; Wang, Yang

2010-07-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication.

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

International Nuclear Information System (INIS)

Guang-Hui, Li; An-Bang, Wang; Ye, Feng; Yang, Wang

2010-01-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication. (general)

Advanced photon source low-energy undulator test line

International Nuclear Information System (INIS)

Milton, S.V.

1997-01-01

The injector system of the Advanced Photon Source (APS) consists of a linac capable of producing 450-MeV positrons or > 650-MeV electrons, a positron accumulator ring (PAR), and a booster synchrotron designed to accelerate particles to 7 GeV. There are long periods of time when these machines are not required for filling the main storage ring and instead can be used for synchrotron radiation research. We describe here an extension of the linac beam transport called the Low-Energy Undulator Test Line (LEUTL). The LEUTL will have a twofold purpose. The first is to fully characterize innovative, future generation undulators, some of which may prove difficult or impossible to measure by traditional techniques. These might include small-gap and superconducting undulators, very long undulators, undulators with designed-in internal focusing, and helical undulators. This technique also holds the promise of extending the magnetic measurement sensitivity beyond that presently attainable. This line will provide the capability to directly test undulators before their possible insertion into operating storage rings. A second use for the test line will be to investigate the generation of coherent radiation at wavelengths down to a few tens of nanometers

Transverse angular momentum in topological photonic crystals

Science.gov (United States)

Deng, Wei-Min; Chen, Xiao-Dong; Zhao, Fu-Li; Dong, Jian-Wen

2018-01-01

Engineering local angular momentum of structured light fields in real space enables applications in many fields, in particular, the realization of unidirectional robust transport in topological photonic crystals with a non-trivial Berry vortex in momentum space. Here, we show transverse angular momentum modes in silicon topological photonic crystals when considering transverse electric polarization. Excited by a chiral external source with either transverse spin angular momentum or transverse phase vortex, robust light flow propagating along opposite directions is observed in several kinds of sharp-turn interfaces between two topologically-distinct silicon photonic crystals. A transverse orbital angular momentum mode with alternating phase vortex exists at the boundary of two such photonic crystals. In addition, unidirectional transport is robust to the working frequency even when the ring size or location of the pseudo-spin source varies in a certain range, leading to the superiority of the broadband photonic device. These findings enable one to make use of transverse angular momentum, a kind of degree of freedom, to achieve unidirectional robust transport in the telecom region and other potential applications in integrated photonic circuits, such as on-chip robust delay lines.

Graphene-based fine-tunable optical delay line for optical beamforming in phased-array antennas.

Science.gov (United States)

Tatoli, Teresa; Conteduca, Donato; Dell'Olio, Francesco; Ciminelli, Caterina; Armenise, Mario N

2016-06-01

The design of an integrated graphene-based fine-tunable optical delay line on silicon nitride for optical beamforming in phased-array antennas is reported. A high value of the optical delay time (τg=920  ps) together with a compact footprint (4.15  mm2) and optical loss graphene-based Mach-Zehnder interferometer switches and two vertically stacked microring resonators between which a graphene capacitor is placed. The tuning range is obtained by varying the value of the voltage applied to the graphene electrodes, which controls the optical path of the light propagation and therefore the delay time. The graphene provides a faster reconfigurable time and low values of energy dissipation. Such significant advantages, together with a negligible beam-squint effect, allow us to overcome the limitations of conventional RF beamformers. A highly efficient fine-tunable optical delay line for the beamsteering of 20 radiating elements up to ±20° in the azimuth direction of a tile in a phased-array antenna of an X-band synthetic aperture radar has been designed.

Toeless pulse shaping with a single delay-line network

International Nuclear Information System (INIS)

Tauhata, L.; Binns, D.C.

1976-04-01

New unipolar delay-line clippers producing negligible cancellation remnant have been developed. Near perfect clipping is achieved using a combination of several types of coaxial cable tranformers working as a phase inverter, a new pulse adder, or an impedance transformer. Only passive elements are used in the bridge network. The construction is simple and the performance is extremely stable and wide in dynamic range and frequency band width. Completely symmetrical bipolar pulses are also easily obtained using this technique

Source of single photons and interferometry with one photon. From the Young's slit experiment to the delayed choice; Source de photons uniques et interferences a un seul photon. De l'experience des fentes d'Young au choix retarde

Energy Technology Data Exchange (ETDEWEB)

Jacques, V

2007-11-15

This manuscript is divided in two independent parts. In the first part, we study the wave-particle duality for a single photon emitted by the triggered photoluminescence of a single NV color center in a diamond nano-crystal. We first present the realization of a single-photon interference experiment using a Fresnel's bi-prism, in a scheme equivalent to the standard Young's double-slit textbook experiment. We then discuss the complementarity between interference and which-path information in this two-path interferometer. We finally describe the experimental realization of Wheeler's delayed-choice Gedanken experiment, which is a fascinating and subtle illustration of wave-particle duality. The second part of the manuscript is devoted to the efficiency improvement of single-photon sources. We first describe the implementation of a new single-photon source based on the photoluminescence of a single nickel-related defect center in diamond. The photophysical properties of such defect make this single-photon source well adapted to open-air quantum cryptography. We finally demonstrate an original method that leads to an improvement of single-molecule photo stability at room temperature. (author)

A new time-digital convert circuit based on digital delay line

International Nuclear Information System (INIS)

Liu Haifeng; Guo Ying; Zhang Zhi

2004-01-01

An introduction of a new method of time-digital convert circuit based on digital delay line is given. High precision and good reliability can be realized when it is combined with traditional counting convert method in the measurement of large scale pulse width and low frequency self-excitation oscillator. (authors)

Attosecond Delays in Molecular Photoionization.

Science.gov (United States)

Huppert, Martin; Jordan, Inga; Baykusheva, Denitsa; von Conta, Aaron; Wörner, Hans Jakob

2016-08-26

We report measurements of energy-dependent photoionization delays between the two outermost valence shells of N_{2}O and H_{2}O. The combination of single-shot signal referencing with the use of different metal foils to filter the attosecond pulse train enables us to extract delays from congested spectra. Remarkably large delays up to 160 as are observed in N_{2}O, whereas the delays in H_{2}O are all smaller than 50 as in the photon-energy range of 20-40 eV. These results are interpreted by developing a theory of molecular photoionization delays. The long delays measured in N_{2}O are shown to reflect the population of molecular shape resonances that trap the photoelectron for a duration of up to ∼110 as. The unstructured continua of H_{2}O result in much smaller delays at the same photon energies. Our experimental and theoretical methods make the study of molecular attosecond photoionization dynamics accessible.

Advanced Photon Counting Imaging Detectors with 100ps Timing for Astronomical and Space Sensing Applications

Science.gov (United States)

Siegmund, O.; Vallerga, J.; Welsh, B.; Rabin, M.; Bloch, J.

In recent years EAG has implemented a variety of high-resolution, large format, photon-counting MCP detectors in space instrumentation for satellite FUSE, GALEX, IMAGE, SOHO, HST-COS, rocket, and shuttle payloads. Our scheme of choice has been delay line readouts encoding photon event position centroids, by determination of the difference in arrival time of the event charge at the two ends of a distributed resistive-capacitive (RC) delay line. Our most commonly used delay line configuration is the cross delay line (XDL). In its simplest form the delay-line encoding electronics consists of a fast amplifier for each end of the delay line, followed by time-to-digital converters (TDC's). We have achieved resolutions of Pulsar with a telescope as small as 1m. Although microchannel plate delay line detectors meet many of the imaging and timing demands of various applications, they have limitations. The relatively high gain (107) reduces lifetime and local counting rate, and the fixed delay (10's of ns) makes multiple simultaneous event recording problematic. To overcome these limitations we have begun development of cross strip readout anodes for microchannel plate detectors. The cross strip (XS) anode is a coarse (~0.5 mm) multi-layer metal and ceramic pattern of crossed fingers on an alumina substrate. The charge cloud is matched to the anode period so that it is collected on several neighboring fingers to ensure an accurate event charge centroid can be determined. Each finger of the anode is connected to a low noise charge sensitive amplifier and followed by subsequent A/D conversion of individual strip charge values and a hardware centroid determination of better than 1/100 of a strip are possible. Recently we have commissioned a full 32 x 32 mm XS open face laboratory detector and demonstrated excellent resolution (Los Alamos National Laboratory, NASA and NSF we are developing high rate (>107 Hz) XS encoding electronics that will encode temporally simultaneous

Two-photon interference of polarization-entangled photons in a Franson interferometer.

Science.gov (United States)

Kim, Heonoh; Lee, Sang Min; Kwon, Osung; Moon, Han Seb

2017-07-18

We present two-photon interference experiments with polarization-entangled photon pairs in a polarization-based Franson-type interferometer. Although the two photons do not meet at a common beamsplitter, a phase-insensitive Hong-Ou-Mandel type two-photon interference peak and dip fringes are observed, resulting from the two-photon interference effect between two indistinguishable two-photon probability amplitudes leading to a coincidence detection. A spatial quantum beating fringe is also measured for nondegenerate photon pairs in the same interferometer, although the two-photon states have no frequency entanglement. When unentangled polarization-correlated photons are used as an input state, the polarization entanglement is successfully recovered through the interferometer via delayed compensation.

A liquid lens switching-based motionless variable fiber-optic delay line

Science.gov (United States)

Khwaja, Tariq Shamim; Reza, Syed Azer; Sheikh, Mumtaz

2018-05-01

We present a Variable Fiber-Optic Delay Line (VFODL) module capable of imparting long variable delays by switching an input optical/RF signal between Single Mode Fiber (SMF) patch cords of different lengths through a pair of Electronically Controlled Tunable Lenses (ECTLs) resulting in a polarization-independent operation. Depending on intended application, the lengths of the SMFs can be chosen accordingly to achieve the desired VFODL operation dynamic range. If so desired, the state of the input signal polarization can be preserved with the use of commercially available polarization-independent ECTLs along with polarization-maintaining SMFs (PM-SMFs), resulting in an output polarization that is identical to the input. An ECTL-based design also improves power consumption and repeatability. The delay switching mechanism is electronically-controlled, involves no bulk moving parts, and can be fully-automated. The VFODL module is compact due to the use of small optical components and SMFs that can be packaged compactly.

Delay-line cables for the fast bumpers in the PS.

CERN Multimedia

CERN PhotoLab

1976-01-01

For 'continuous transfer' to the SPS, the beam accelerated in the PS is shaved off over several turns, so as to form a continuous sequence of bunches several times the length of the PS circumference. Fast bumpers, powered in a 'staircase' way, displace the PS beam stepwise towards the ejection septum. Each step lasts 2.1 microsec and the cable drums in this picture contain some of the bumper delay-lines of altogether 10 km.

2Kx2K resolution element photon counting MCP sensor with >200 kHz event rate capability

CERN Document Server

Vallerga, J V

2000-01-01

Siegmund Scientific undertook a NASA Small Business Innovative Research (SBIR) contract to develop a versatile, high-performance photon (or particle) counting detector combining recent technical advances in all aspects of Microchannel Plate (MCP) detector development in a low cost, commercially viable package that can support a variety of applications. The detector concept consists of a set of MCPs whose output electron pulses are read out with a crossed delay line (XDL) anode and associated high-speed event encoding electronics. The delay line anode allows high-resolution photon event centroiding at very high event rates and can be scaled to large formats (>40 mm) while maintaining good linearity and high temporal stability. The optimal sensitivity wavelength range is determined by the choice of opaque photocathodes. Specific achievements included: spatial resolution of 200 000 events s sup - sup 1; local rates of >100 events s sup - sup 1 per resolution element; event timing of <1 ns; and low background ...

Constructing Hopf bifurcation lines for the stability of nonlinear systems with two time delays

Science.gov (United States)

Nguimdo, Romain Modeste

2018-03-01

Although the plethora real-life systems modeled by nonlinear systems with two independent time delays, the algebraic expressions for determining the stability of their fixed points remain the Achilles' heel. Typically, the approach for studying the stability of delay systems consists in finding the bifurcation lines separating the stable and unstable parameter regions. This work deals with the parametric construction of algebraic expressions and their use for the determination of the stability boundaries of fixed points in nonlinear systems with two independent time delays. In particular, we concentrate on the cases for which the stability of the fixed points can be ascertained from a characteristic equation corresponding to that of scalar two-delay differential equations, one-component dual-delay feedback, or nonscalar differential equations with two delays for which the characteristic equation for the stability analysis can be reduced to that of a scalar case. Then, we apply our obtained algebraic expressions to identify either the parameter regions of stable microwaves generated by dual-delay optoelectronic oscillators or the regions of amplitude death in identical coupled oscillators.

Automated Sample Exchange Robots for the Structural Biology Beam Lines at the Photon Factory

International Nuclear Information System (INIS)

Hiraki, Masahiko; Watanabe, Shokei; Yamada, Yusuke; Matsugaki, Naohiro; Igarashi, Noriyuki; Gaponov, Yurii; Wakatsuki, Soichi

2007-01-01

We are now developing automated sample exchange robots for high-throughput protein crystallographic experiments for onsite use at synchrotron beam lines. It is part of the fully automated robotics systems being developed at the Photon Factory, for the purposes of protein crystallization, monitoring crystal growth, harvesting and freezing crystals, mounting the crystals inside a hutch and for data collection. We have already installed the sample exchange robots based on the SSRL automated mounting system at our insertion device beam lines BL-5A and AR-NW12A at the Photon Factory. In order to reduce the time required for sample exchange further, a prototype of a double-tonged system was developed. As a result of preliminary experiments with double-tonged robots, the sample exchange time was successfully reduced from 70 seconds to 10 seconds with the exception of the time required for pre-cooling and warming up the tongs

Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

Energy Technology Data Exchange (ETDEWEB)

Wu, Tony C.; Congreve, Daniel N.; Baldo, Marc A., E-mail: baldo@mit.edu [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2015-07-20

The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator is 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.

On beam shaping of the field radiated by a line source coupled to finite or infinite photonic crystals.

Science.gov (United States)

Ceccuzzi, Silvio; Jandieri, Vakhtang; Baccarelli, Paolo; Ponti, Cristina; Schettini, Giuseppe

2016-04-01

Comparison of the beam-shaping effect of a field radiated by a line source, when an ideal infinite structure constituted by two photonic crystals and an actual finite one are considered, has been carried out by means of two different methods. The lattice sums technique combined with the generalized reflection matrix method is used to rigorously investigate the radiation from the infinite photonic crystals, whereas radiation from crystals composed of a finite number of rods along the layers is analyzed using the cylindrical-wave approach. A directive radiation is observed with the line source embedded in the structure. With an increased separation distance between the crystals, a significant edge diffraction appears that provides the main radiation mechanism in the finite layout. Suitable absorbers are implemented to reduce the above-mentioned diffraction and the reflections at the boundaries, thus obtaining good agreement between radiation patterns of a localized line source coupled to finite and infinite photonic crystals, when the number of periods of the finite structure is properly chosen.

Ultra-Wide Band Non-reciprocity through Sequentially-Switched Delay Lines.

Science.gov (United States)

Biedka, Mathew M; Zhu, Rui; Xu, Qiang Mark; Wang, Yuanxun Ethan

2017-01-06

Achieving non-reciprocity through unconventional methods without the use of magnetic material has recently become a subject of great interest. Towards this goal a time switching strategy known as the Sequentially-Switched Delay Line (SSDL) is proposed. The essential SSDL configuration consists of six transmission lines of equal length, along with five switches. Each switch is turned on and off sequentially to distribute and route the propagating electromagnetic wave, allowing for simultaneous transmission and receiving of signals through the device. Preliminary experimental results with commercial off the shelf parts are presented which demonstrated non-reciprocal behavior with greater than 40 dB isolation from 200 KHz to 200 MHz. The theory and experimental results demonstrated that the SSDL concept may lead to future on-chip circulators over multi-octaves of frequency.

Can Two-Photon Interference be Considered the Interference of Two Photons?

International Nuclear Information System (INIS)

Pittman, T.B.; Strekalov, D.V.; Migdall, A.; Rubin, M.H.; Sergienko, A.V.; Shih, Y.H.

1996-01-01

We report on a open-quote open-quote postponed compensation close-quote close-quote experiment in which the observed two-photon entangled state interference cannot be pictured in terms of the overlap of the two individual photon wave packets of a parametric down-conversion pair on a beam splitter. In the sense of a quantum eraser, the distinguishability of the different two-photon Feynman amplitudes leading to a coincidence detection is removed by delaying the compensation until after the output of an unbalanced two-photon interferometer. copyright 1996 The American Physical Society

Nuclei far from the beta stability line. High-energy beta decay and delayed-particle emission

International Nuclear Information System (INIS)

Hansen, R.G.; Hornshj, P.

1976-01-01

Progress in on-line mass separation together with improved proton accelerators now permit the production of secondary ion-beams of the order of 10 11 atoms per second. Applications to the study of delayed-proton and delayed-alpha emission are discussed. These effects have been used for the estimation of alpha-emission strength functions at 4-6 MeV excitation energy, and for the determination of level densities through fluctuation analysis

A low dead time vernier delay line TDC implemented in an Actel flash-based FPGA

International Nuclear Information System (INIS)

Qin Xi; Feng Changqing; Zhang Deliang; Zhao Lei; Liu Shubin; An Qi

2013-01-01

In this paper, a high precision vernier delay line (VDL) TDC (Time-to-Digital Converter) in an Actel flash-based Field-Programmable-Gate-Arrays A3PE1500 is implemented, achieving a resolution of 16.4-ps root mean square value or 42-ps averaged bin size. The TDC has a dead time of about 200 ns while the dynamic range is 655.36 Vs. The double delay lines method is employed to cut the dead time in half to improve its performance. As the bin size of the TDC is dependent on temperature, a compensation algorithm is adopted as temperature drift correction, and the TDC shows satisfying performance in a temperature range from -5℃ to +55℃. (authors)

Optics of globular photonic crystals

International Nuclear Information System (INIS)

Gorelik, V S

2007-01-01

The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ∼200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported. (review)

Optics of Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): Delay Lines and Alignment

Science.gov (United States)

Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Fixsen, Dale; Sampler, Henry; Mentzell, Eric; Veach, Todd; Silverberg, Robert F.; Furst, Stephen;

Geodesic curve-of-sight formulae for the cosmic microwave background: a unified treatment of redshift, time delay, and lensing

International Nuclear Information System (INIS)

Saito, Ryo; Naruko, Atsushi; Hiramatsu, Takashi; Sasaki, Misao

2014-01-01

In this paper, we introduce a new approach to a treatment of the gravitational effects (redshift, time delay and lensing) on the observed cosmic microwave background (CMB) anisotropies based on the Boltzmann equation. From the Liouville's theorem in curved spacetime, the intensity of photons is conserved along a photon geodesic when non-gravitational scatterings are absent. Motivated by this fact, we derive a second-order line-of-sight formula by integrating the Boltzmann equation along a perturbed geodesic (curve) instead of a background geodesic (line). In this approach, the separation of the gravitational and intrinsic effects are manifest. This approach can be considered as a generalization of the remapping approach of CMB lensing, where all the gravitational effects can be treated on the same footing

75 FR 78928 - Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan, Delay of Effective...

Science.gov (United States)

2010-12-17

...-AA17 Limited Service Domestic Voyage Load Lines for River Barges on Lake Michigan, Delay of Effective Date AGENCY: Coast Guard, DHS. ACTION: Notice of delay of effective date and reopening of the comment... 46 CFR part 45 as amended by the final rule published in the November 18, 2010, Federal Register (75...

Large-bandwidth planar photonic crystal waveguides

DEFF Research Database (Denmark)

Søndergaard, Thomas; Lavrinenko, Andrei

2002-01-01

A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

Neutron and photon clonogenic survival curves of two chemotherapy resistant human intermediate-grade non-Hodgkin lymphoma cell lines

International Nuclear Information System (INIS)

Aref, Amr; Yudelev, Mark; Mohammad, Ramzi; Choudhuri, Rajani; Orton, Colin; Al-Katib, Ayad

1999-01-01

Background: The potential role of neutron therapy in the management of intermediate-grade non-Hodgkin lymphoma (IGNHL) has not been examined because of the belief that the anticipated radiobiological effectiveness (RBE) would be uniformly very low. Purpose: To determine the fast neutron RBE for two chemotherapy-resistant IGNHL cell lines. Methods and Materials: Conventional soft agar clonogenic survival curves following irradiation by 60 Co and fast neutron were established for two IGNHL cell lines. These cell lines, WSU-DLCL2 and SK-DHL2B, were found in previous studies to be able to repair sublethal damage, and were also resistant to L-Pam and doxorubicin chemotherapy. Results: When the surviving fraction after 2 Gy photon was chosen as the biological endpoint, the RBE for WSU-DLCL2 and SK-DHL2B measured 3.34 and 3.06. Similarly, when 10% survival was considered, the RBE for these two cell lines measured 2.54 and 2.59. The RBE, as measured by the ratios α neutron/α photon, for WSU-DLCL2, SK-DHL2B cell lines are 6.67 and 5.65, respectively. These results indicate that the RBE for these IGNHL cell lines is higher than the average RBE for cell lines of other histological types. Conclusion: Fast neutron irradiation may be of potential value in treating selected cases of IGNHL

Optimum steering of photon beam lines in SPEAR

International Nuclear Information System (INIS)

Corbett, W.J.; Fong, B.; Lee, M.; Ziemann, V.

1993-04-01

A common operational requirement for many synchrotron light sources is to maintain steered photon beamlines with minimum corrector strength values. To solve this problem for SPEAR, we employed the Singular Value Decomposition (SVD) matrix-inversion technique to minimize corrector strengths while constraining the photon beamlines to remain on target. The result was a reduction in corrector strengths, yielding increased overhead for the photon-beam position feedback systems

Peculiar time dependence of unexpected lines in delayed beam-foil X-ray spectra of V, Fe and Ni

International Nuclear Information System (INIS)

Ahmad, Nissar; Karn, Ranjeet K.; Marketos, Pan; Nandi, T.

2005-01-01

Delayed beam-foil X-ray spectra of highly charged ions of V, Fe and Ni show a few lines at energies higher than the H-like Lyman α-line of the respective projectile ions. These can only be attributed to heavier ions. Further the time dependence of such unexpected lines display a peculiar behavior. This work presents the experimental observations systematically

Single-photon detector operating under extremely high background photon flux conditions

International Nuclear Information System (INIS)

Prochazka, Ivan; Sopko, Bruno; Blazej, Josef

2009-01-01

We are reporting our results in research and development in the field of avalanche semiconductor single-photon detectors and their application. Our goal was a development of a solid-state photon-counting detector capable of high-precision photon arrival time tagging in extremely harsh operating conditions. The background photon flux exceeding 10 9 photons per second hitting the detector active area should not avoid the useful signal detection and recognition on the signal level of units of photons per second. This is background photon flux about two orders of magnitude higher than what the conventional solid-state photon counters accept. The detection timing resolution should be better than 100 ps and the delay stability should be on picosecond level. We have developed and tested the active quenched and gated avalanche structure on silicon providing the required features in connection with the K14 detection chips. The detector is capable of gated operation under the conditions of background photon flux of 5x10 9 photons per second. The operational detector tolerates long term exposures to the input photon flux exceeding 10 15 photons (>1 mW) per second without damage.

REVIEW: Optics of globular photonic crystals

Science.gov (United States)

Gorelik, V. S.

2007-05-01

The results of experimental and theoretical studies of the optical properties of globular photonic crystals - new physical objects having a crystal structure with the lattice period exceeding considerably the atomic size, are presented. As globular photonic crystals, artificial opal matrices consisting of close-packed silica globules of diameter ~200 nm were used. The reflection spectra of these objects characterising the parameters of photonic bands existing in these crystals in the visible spectral region are presented. The idealised models of the energy band structure of photonic crystals investigated in the review give analytic dispersion dependences for the group velocity and the effective photon mass in a globular photonic crystal. The characteristics of secondary emission excited in globular photonic crystals by monochromatic and broadband radiation are presented. The results of investigations of single-photon-excited delayed scattering of light observed in globular photonic crystals exposed to cw UV radiation and radiation from a repetitively pulsed copper vapour laser are presented. The possibilities of using globular photonic crystals as active media for lasing in different spectral regions are considered. It is proposed to use globular photonic crystals as sensitive sensors in optoelectronic devices for molecular analysis of organic and inorganic materials by the modern methods of laser spectroscopy. The results of experimental studies of spontaneous and stimulated globular scattering of light are discussed. The conditions for observing resonance and two-photon-excited delayed scattering of light are found. The possibility of accumulation and localisation of the laser radiation energy inside a globular photonic crystal is reported.

Data readout system utilizing photonic integrated circuit

Energy Technology Data Exchange (ETDEWEB)

Stopiński, S., E-mail: S.Stopinski@tue.nl [COBRA Research Institute, Eindhoven University of Technology (Netherlands); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Malinowski, M.; Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology (Poland); Smit, M.K.; Leijtens, X.J.M. [COBRA Research Institute, Eindhoven University of Technology (Netherlands)

2013-10-11

We describe a novel optical solution for data readout systems. The core of the system is an Indium-Phosphide photonic integrated circuit performing as a front-end readout unit. It functions as an optical serializer in which the serialization of the input signal is provided by means of on-chip optical delay lines. The circuit employs electro-optic phase shifters to build amplitude modulators, power splitters for signal distribution, semiconductor optical amplifiers for signal amplification as well as on-chip reflectors. We present the concept of the system, the design and first characterization results of the devices that were fabricated in a multi-project wafer run.

Amplified Photon Upconversion by Photonic Shell of Cholesteric Liquid Crystals.

Science.gov (United States)

Kang, Ji-Hwan; Kim, Shin-Hyun; Fernandez-Nieves, Alberto; Reichmanis, Elsa

2017-04-26

As an effective platform to exploit triplet-triplet-annihilation-based photon upconversion (TTA-UC), microcapsules composed of a fluidic UC core and photonic shell are microfluidically prepared using a triple emulsion as the template. The photonic shell consists of cholesteric liquid crystals (CLCs) with a periodic helical structure, exhibiting a photonic band gap. Combined with planar anchoring at the boundaries, the shell serves as a resonance cavity for TTA-UC emission and enables spectral tuning of the UC under low-power-density excitation. The CLC shell can be stabilized by introducing a polymerizable mesogen in the LC host. Because of the microcapsule spherical symmetry, spontaneous emission of the delayed fluorescence is omnidirectionally amplified at the edge of the stop band. These results demonstrate the range of opportunities provided by TTA-UC systems for the future design of low-threshold photonic devices.

A two-dimensional detector with delay line readout for slow neutron fields measurements

International Nuclear Information System (INIS)

Cheremukhina, G.A.; Chernenko, S.P.; Ivanov, A.B.

1992-01-01

This article presents the description of a two-dimensional detector of slow neutrons together with its readout and data acquisition electronics based on a PC/AT> The detector with a sensitive area of 260x140 mm 2 is based on a high pressure multiwire proportional chamber with delay line readout and gas filling of 3.0 atm. 3 He + propane. 25 refs.; 10 figs.; 2 tabs

Characteristics of a delay-line readout in a cylindrical drift chamber system

International Nuclear Information System (INIS)

Barber, R.; Ahmed, M.W.; Dzemidzic, M.; Empl, A.; Hungerford, E.V.; Lan, K.J.; Wilson, J.; Cooper, M.D.; Gagliardi, C.A.; Haim, D.; Kim, G.J.; Koetke, D.D.; Tribble, R.E.; Van Ausdeln, L.A.

2002-01-01

This paper reports on the design, construction, and operational characteristics of a delay-line readout implemented on the cathode foils of a cylindrical drift chamber system. The readout was used to determine the position of an event along the length of the 1.74 m drift wires in the MEGA detectors used at the Los Alamos Meson Physics Facility. The performance of the system is interpreted by comparison to a PSPICE simulation, and to simple analytical models

Line photon transport in a non-homogeneous plasma using radiative coupling coefficients

International Nuclear Information System (INIS)

Florido, R.; Gil, J.M.; Rodriguez, R.; Rubiano, J.G.; Martel, P.; Florido, R.; Gil, J.M.; Rodriguez, R.; Rubiano, J.G.; Martel, P.; Minguez, E.

2006-01-01

We present a steady-state collisional-radiative model for the calculation of level populations in non-homogeneous plasmas with planar geometry. The line photon transport is taken into account following an angle- and frequency-averaged escape probability model. Several models where the same approach has been used can be found in the literature, but the main difference between our model and those ones is that the details of geometry are exactly treated in the definition of coupling coefficients and a local profile is taken into account in each plasma cell. (authors)

On-line hyperfine structure and isotope shift measurements with diffuse light collection and photon burst detection

International Nuclear Information System (INIS)

Lassen, J.; Benck, E.C.; Schuessler, H.A.

1997-01-01

An experiment is presently being set up which combines collinear-fast-beam laser spectroscopy with photon burst spectroscopy. Selectivity is provided by the large kinetic isotope shifts together with the practically Doppler free linewidth of the fluorescence from the fast atom beam. The photon burst detection, based on photon correlations in the resonance fluorescence, increases the sensitivity, so that on-line optical isotope shift and hyperfine structure measurements on low intensity radioactive beams become feasible. In order to improve photon burst detection the solid angle of detection and the observation time have to be optimized. To this end a diffuse reflecting cavity has been designed and built, which collects fluorescence over a 45 cm length of the beam and covers the full solid angle. The light collection efficiency of the cavity is calculated to be about 45%. The cavity is being tested with a 11 keV beam of krypton atoms, probing the near infrared transitions in our apparatus at Texas A ampersand M University. copyright 1997 American Institute of Physics

Ultra-precision turning of complex spiral optical delay line

Science.gov (United States)

Zhang, Xiaodong; Li, Po; Fang, Fengzhou; Wang, Qichang

2011-11-01

Optical delay line (ODL) implements the vertical or depth scanning of optical coherence tomography, which is the most important factor affecting the scanning resolution and speed. The spinning spiral mirror is found as an excellent optical delay device because of the high-speed and high-repetition-rate. However, it is one difficult task to machine the mirror due to the special shape and precision requirement. In this paper, the spiral mirror with titled parabolic generatrix is proposed, and the ultra-precision turning method is studied for its machining using the spiral mathematic model. Another type of ODL with the segmental shape is also introduced and machined to make rotation balance for the mass equalization when scanning. The efficiency improvement is considered in details, including the rough cutting with the 5- axis milling machine, the machining coordinates unification, and the selection of layer direction in turning. The onmachine measuring method based on stylus gauge is designed to analyze the shape deviation. The air bearing is used as the measuring staff and the laser interferometer sensor as the position sensor, whose repeatability accuracy is proved up to 10nm and the stable feature keeps well. With this method developed, the complex mirror with nanometric finish of 10.7nm in Ra and the form error within 1um are achieved.

Clock-frequency and temperature margins of a high-temperature superconductor delay-line memory

International Nuclear Information System (INIS)

Hattori, W.; Tahara, S.

1999-01-01

We have developed a 10 GHz 32-bit delay-line memory, using a semiconductor crossbar switch and a YBa 2 Cu 3 O 7-δ coplanar delay line. For use in the high-speed (≥10 GHz) cell-buffer storage of large-throughput (≥1 Tbit/s) asynchronous transfer mode (ATM) switching systems, this memory must be fairly reliable. To evaluate the reliability of the operation, therefore, we measured the clock-frequency and temperature margins and the temperature dependence of the bit-error rate. At 64 K, this memory has a capacity of 32 bits with a clock frequency of 9.89±0.11 GHz. In general, clock frequencies of communication systems are strictly managed so that the margins are less than 10 -6 . Therefore, the frequency margin of this memory (∼2x10 -2 )) is wide enough for use in communication systems. The temperature margin was 71.5±4.3 K at 10 GHz and 33 bits. This memory offered error-free operation (BER -13 ) at 71.5 ±3.5 K. These temperature margins are wide enough to be controlled by a cryocooler. These results show that the memory offers reliability and that it can be applied to high-speed ATM cell-buffer storage. (author)

A Polynomial Estimate of Railway Line Delay

DEFF Research Database (Denmark)

Cerreto, Fabrizio; Harrod, Steven; Nielsen, Otto Anker

2017-01-01

Railway service may be measured by the aggregate delay over a time horizon or due to an event. Timetables for railway service may dampen aggregate delay by addition of additional process time, either supplement time or buffer time. The evaluation of these variables has previously been performed...

Advanced materials for the optical delay line of frequency pulse modulator on the basis of semiconductor laser

International Nuclear Information System (INIS)

Abrarov, S.M.

1999-01-01

In the paper some materials which can be sued as an optical delay line of the pulse frequency modulator are considered. The structure and the principle are described as a modulator consisting of a laser diode with two Fabry Perot resonators and an optical wave guide providing a feedback loop. The optical wave guide fulfills the function of delay line and links the two resonators. The pulse sequence of the radiation of the semiconductor laser arises due to failure and recovery of optical generation. The pulse frequency modulation can be carried out by the action of electrical tension field on the electro optic martial of the wave guide. The selection of three electro-optic crystals for making of the optical wave guide of the considered modulator is justified. (author)

Optical Time Division Switching Using Multiple Stages of Fiber Optic Delay Lines.

Science.gov (United States)

Spanke, Ronald Anthony

Optical Time Slot Interchanges (OTSIs) can be realized by guided wave LiNbO_3 optical switches performing space division switching of optical fiber delay lines. In this dissertation the problems of reducing the total length of fiber required and also of improving the SNR characteristics of this OTSI function are addressed. Several new OTSI architectures are proposed to reduce the total fiber length while still obtaining excellent SNR characteristics. These reduced fiber architectures include the Distributed Input Delay, Distributed Output Delay, the 2-Stage decomposition and the Distributed Input/Output Delay architectures. A Parallel Feedback (PFB) OTSI architecture is proposed that achieves the theoretical minimum number of delay fibers and the theoretical minimum total length of delay fiber for a given OTSI function. Broadcast OTSI architectures are proposed that enable the data in an incoming time slot to be broadcast to one or more outgoing time slots. These broadcast OTSI architectures include the Time-Dup-Time (TDT) system, Passive Splitter/Active Combiner (PS/AC) equivalents of the point -to-point reduced fiber architectures, and the broadcast PFB architecture. For each of the point-to-point and the broadcast OTSI architectures proposed, a detailed characterization of the architecture is performed including an analysis of number of fibers, total fiber length, number of optical switches and drivers, attenuation and SNR characteristics. This dissertation also proposes several new techniques for improving the system SNR and for calibration of the OTSI architectures. A cascaded noise reduction and a differential attenuation compensation technique are used to achieve a significantly higher system SNR at the output of the OTSI. In-situ calibration techniques are discussed to determine the optimum operating voltages for the LiNbO _3 switches when alternating between states every time slot. These techniques attempt to compensate for an output power drift problem

Secured Optical Communications Using Quantum Entangled Two-Photon Transparency Modulation

Science.gov (United States)

Kojima, Jun (Inventor); Nguyen, Quang-Viet (Inventor); Lekki, John (Inventor)

2015-01-01

A system and method is disclosed wherein optical signals are coded in a transmitter by tuning or modulating the interbeam delay time (which modulates the fourth-order coherence) between pairs of entangled photons. The photon pairs are either absorbed or not absorbed (transparent) by an atomic or molecular fluorescer in a receiver, depending on the inter-beam delay that is introduced in the entangled photon pairs. Upon the absorption, corresponding fluorescent optical emissions follow at a certain wavelength, which are then detected by a photon detector. The advantage of the disclosed system is that it eliminates a need of a coincidence counter to realize the entanglement-based secure optical communications because the absorber acts as a coincidence counter for entangled photon pairs.

Femtosecond Photon-Counting Receiver

Science.gov (United States)

Krainak, Michael A.; Rambo, Timothy M.; Yang, Guangning; Lu, Wei; Numata, Kenji

2016-01-01

An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.

ABSORPTION-LINE SPECTROSCOPY OF GRAVITATIONALLY LENSED GALAXIES: FURTHER CONSTRAINTS ON THE ESCAPE FRACTION OF IONIZING PHOTONS AT HIGH REDSHIFT

Energy Technology Data Exchange (ETDEWEB)

Leethochawalit, Nicha; Ellis, Richard S.; Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Jones, Tucker A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Stark, Daniel P. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

2016-11-10

The fraction of ionizing photons escaping from high-redshift star-forming galaxies is a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. We previously proposed using the covering fraction of low-ionization gas, measured via deep absorption-line spectroscopy, as a proxy. We now present a significant update, sampling seven gravitationally lensed sources at 4 < z < 5. We show that the absorbing gas in our sources is spatially inhomogeneous, with a median covering fraction of 66%. Correcting for reddening according to a dust-in-cloud model, this implies an estimated absolute escape fraction of ≃19% ± 6%. With possible biases and uncertainties, collectively we find that the average escape fraction could be reduced to no less than 11%, excluding the effect of spatial variations. For one of our lensed sources, we have sufficient signal-to-noise ratio to demonstrate the presence of such spatial variations and scatter in its dependence on the Ly α equivalent width, consistent with recent simulations. If this source is typical, our lower limit to the escape fraction could be reduced by a further factor ≃2. Across our sample, we find a modest anticorrelation between the inferred escape fraction and the local star formation rate, consistent with a time delay between a burst and leaking Lyman continuum photons. Our analysis demonstrates considerable variations in the escape fraction, consistent with being governed by the small-scale behavior of star-forming regions, whose activities fluctuate over short timescales. This supports the suggestion that the escape fraction may increase toward the reionization era when star formation becomes more energetic and burst-like.

Characterization of a remote optical element with bi-photons

Science.gov (United States)

Puhlmann, D.; Henkel, C.; Heuer, A.; Pieplow, G.; Menzel, R.

2016-02-01

We present a simple setup that exploits the interference of entangled photon pairs. ‘Signal’ photons are sent through a Mach-Zehnder-like interferometer, while ‘idlers’ are detected in a variable polarization state. Two-photon interference (in coincidence detection) is observed with very high contrast and for significant time delays between signal and idler detection events. This is explained by quantum erasure of the polarization tag and a delayed choice protocol involving a non-local virtual polarizer. The phase of the two-photon fringes is scanned by varying the path length in the signal beam or by rotating a birefringent crystal in the idler beam. We exploit this to characterize one beam splitter of the signal photon interferometer (reflection and transmission amplitudes including losses), using only information about coincidences and control parameters in the idler path. This is possible because our bi-photon state saturates the Greenberger-Yelin-Englert inequality between contrast and predictability.

Characterization of a remote optical element with bi-photons

International Nuclear Information System (INIS)

Puhlmann, D; Henkel, C; Heuer, A; Pieplow, G; Menzel, R

2016-01-01

We present a simple setup that exploits the interference of entangled photon pairs. ‘Signal’ photons are sent through a Mach–Zehnder-like interferometer, while ‘idlers’ are detected in a variable polarization state. Two-photon interference (in coincidence detection) is observed with very high contrast and for significant time delays between signal and idler detection events. This is explained by quantum erasure of the polarization tag and a delayed choice protocol involving a non-local virtual polarizer. The phase of the two-photon fringes is scanned by varying the path length in the signal beam or by rotating a birefringent crystal in the idler beam. We exploit this to characterize one beam splitter of the signal photon interferometer (reflection and transmission amplitudes including losses), using only information about coincidences and control parameters in the idler path. This is possible because our bi-photon state saturates the Greenberger–Yelin–Englert inequality between contrast and predictability. (invited comment)

A Neutron Sensitive Microchannel Plate Detector with Cross Delay Line Readout

International Nuclear Information System (INIS)

Berry, Kevin D.; Bilheux, Hassina Z.; Crow, Lowell; Diawara, Yacouba; Feller, W. Bruce; Iverson, Erik B.; Martin, Adrian; Robertson, J. Lee

2012-01-01

Microchannel plates containing neutron absorbing elements such as boron and gadolinium in the bulk glass are used as the sensing element in high spatial resolution, high rate neutron imaging systems. In this paper we describe one such device, using both 10 B and natural Gd, which employs cross delay line signal readout, with time-of-flight capability. This detector has a measured spatial resolution under 40 m FWHM, thermal neutron efficiency of 19%, and has recorded rates in excess of 500 kHz. A physical and functional description is presented, followed by a discussion of measurements of detector performance and a brief survey of some practical applications.

Non-thermal gamma-ray emission from delayed pair breakdown in a magnetized and photon-rich outflow

Energy Technology Data Exchange (ETDEWEB)

Gill, Ramandeep; Thompson, Christopher, E-mail: rgill@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

2014-12-01

We consider delayed, volumetric heating in a magnetized outflow that has broken out of a confining medium and expanded to a high Lorentz factor (Γ ∼ 10{sup 2}-10{sup 3}) and low optical depth to scattering (τ {sub T} ∼ 10{sup –3}-10{sup –2}). The energy flux at breakout is dominated by the magnetic field, with a modest contribution from quasi-thermal gamma rays whose spectrum was calculated in Paper I. We focus on the case of extreme baryon depletion in the magnetized material, but allow for a separate baryonic component that is entrained from a confining medium. Dissipation is driven by relativistic motion between these two components, which develops once the photon compactness drops below 4 × 10{sup 3}(Y{sub e} /0.5){sup –1}. We first calculate the acceleration of the magnetized component following breakout, showing that embedded MHD turbulence provides significant inertia, the neglect of which leads to unrealistically high estimates of flow Lorentz factor. After reheating begins, the pair and photon distributions are evolved self-consistently using a one-zone kinetic code that incorporates an exact treatment of Compton scattering, pair production and annihilation, and Coulomb scattering. Heating leads to a surge in pair creation, and the scattering depth saturates at τ {sub T} ∼ 1-4. The plasma maintains a very low ratio of particle to magnetic pressure, and can support strong anisotropy in the charged particle distribution, with cooling dominated by Compton scattering. High-energy power-law spectra with photon indices in the range observed in gamma-ray bursts (GRBs; –3 < β < –3/2) are obtained by varying the ratio of heat input to the seed energy in quasi-thermal photons. We contrast our results with those for continuous heating across an expanding photosphere, and show that the latter model produces soft-to-hard evolution that is inconsistent with observations of GRBs.

Realization of compact tractor beams using acoustic delay-lines

Science.gov (United States)

Marzo, A.; Ghobrial, A.; Cox, L.; Caleap, M.; Croxford, A.; Drinkwater, B. W.

2017-01-01

A method for generating stable ultrasonic levitation of physical matter in air using single beams (also known as tractor beams) is demonstrated. The method encodes the required phase modulation in passive unit cells into which the ultrasonic sources are mounted. These unit cells use waveguides such as straight and coiled tubes to act as delay-lines. It is shown that a static tractor beam can be generated using a single electrical driving signal, and a tractor beam with one-dimensional movement along the propagation direction can be created with two signals. Acoustic tractor beams capable of holding millimeter-sized polymer particles of density 1.25 g/cm3 and fruit-flies (Drosophila) are demonstrated. Based on these design concepts, we show that portable tractor beams can be constructed with simple components that are readily available and easily assembled, enabling applications in industrial contactless manipulation and biophysics.

Dynamic measurements at THz frequencies with a fast rotary delay line

Science.gov (United States)

Guerboukha, Hichem; Markov, Andrey; Qu, Hang; Skorobogatiy, Maksim

2016-02-01

Fabrication, characterization, and applications of a fast rotary linear optical delay line (FRLODL) for THz time-domain spectroscopy are presented. The FRLODL features two reflective surfaces with spatially separated incoming and outgoing beams. It has been manufactured using CNC machining. A linear dependence of the optical delay on the rotation angle allows a straightforward extraction of the conversion factor between the acquisition time (in ms) and the terahertz pulse time (in ps). The FRLODL has been tested using rotation speeds of up to 48 Hz, corresponding to an acquisition rate of up to 192 Hz with four blades incorporated on the same disk. At high speeds we observe a decrease of the bandwidth due to the limitations of the electronics, in particular, the transimpedance amplifier. An error analysis is performed by experimentally evaluating the signal-to-noise ratio and the dynamic range. With regard to the applications of the FRLODL, we first present observation of the evaporation of liquids, namely water, acetone and methanol. We then demonstrate monitoring of the spray painting process. Finally, detection of fast moving objects at 1 m/s and their thickness characterization are presented.

Theory of attosecond delays in molecular photoionization.

Science.gov (United States)

Baykusheva, Denitsa; Wörner, Hans Jakob

2017-03-28

We present a theoretical formalism for the calculation of attosecond delays in molecular photoionization. It is shown how delays relevant to one-photon-ionization, also known as Eisenbud-Wigner-Smith delays, can be obtained from the complex dipole matrix elements provided by molecular quantum scattering theory. These results are used to derive formulae for the delays measured by two-photon attosecond interferometry based on an attosecond pulse train and a dressing femtosecond infrared pulse. These effective delays are first expressed in the molecular frame where maximal information about the molecular photoionization dynamics is available. The effects of averaging over the emission direction of the electron and the molecular orientation are introduced analytically. We illustrate this general formalism for the case of two polyatomic molecules. N 2 O serves as an example of a polar linear molecule characterized by complex photoionization dynamics resulting from the presence of molecular shape resonances. H 2 O illustrates the case of a non-linear molecule with comparably simple photoionization dynamics resulting from a flat continuum. Our theory establishes the foundation for interpreting measurements of the photoionization dynamics of all molecules by attosecond metrology.

Photonic Low Cost Micro-Sensor for in-Line Wear Particle Detection in Flowing Lube Oils

Directory of Open Access Journals (Sweden)

Jon Mabe

2017-03-01

Full Text Available The presence of microscopic particles in suspension in industrial fluids is often an early warning of latent or imminent failures in the equipment or processes where they are being used. This manuscript describes work undertaken to integrate different photonic principles with a micro- mechanical fluidic structure and an embedded processor to develop a fully autonomous wear debris sensor for in-line monitoring of industrial fluids. Lens-less microscopy, stroboscopic illumination, a CMOS imager and embedded machine vision technologies have been merged to develop a sensor solution that is able to detect and quantify the number and size of micrometric particles suspended in a continuous flow of a fluid. A laboratory test-bench has been arranged for setting up the configuration of the optical components targeting a static oil sample and then a sensor prototype has been developed for migrating the measurement principles to real conditions in terms of operating pressure and flow rate of the oil. Imaging performance is quantified using micro calibrated samples, as well as by measuring real used lubricated oils. Sampling a large fluid volume with a decent 2D spatial resolution, this photonic micro sensor offers a powerful tool at very low cost and compacted size for in-line wear debris monitoring.

Benchmarking state-of-the-art numerical simulation techniques for analyzing large photonic crystal membrane line defect cavities

DEFF Research Database (Denmark)

Gregersen, Niels; de Lasson, Jakob Rosenkrantz; Frandsen, Lars Hagedorn

2018-01-01

In this work, we perform numerical studies of two photonic crystal membrane microcavities, a short line-defect L5 cavity with relatively low quality (Q) factor and a longer L9 cavity with high Q. We compute the cavity Q factor and the resonance wavelength λ of the fundamental M1 mode in the two...

The MEL-X project at the Lawrence Livermore National Laboratory: a mirror-based delay line for x-rays

Science.gov (United States)

Pardini, Tom; Hill, Randy; Decker, Todd; Alameda, Jennifer; Soufli, Regina; Aquila, Andy; Guillet, Serge; Boutet, Sébastien; Hau-Riege, Stefan P.

2015-09-01

At the Lawrence Livermore National Laboratory (LLNL) in collaboration with the Linac Coherent Light Source (LCLS) we are developing a mirror-based delay line for x-rays (MEL-X) to enable x-ray pump/x-ray probe experiments at Free Electron Lasers (XFELs). The goal of this project is the development and deployment of a proof-of-principle delay line featuring coated x-ray optics. The four-mirror design of the MEL-X is motivated by the need for ease of alignment and use. In order to simplify the overlap of the pump and the probe beam after each delay time change, a scheme involving super-polished rails and mirror-to-motor decoupling has been adopted. The MEL-X, used in combination with a bright pulsed source like LCLS, features a capability for a high intensity pump beam. Its Iridium coating allows it to work at hard x-ray energies all the way up to 9 keV, with a probe beam transmission of 35% up to 8keV, and 14% at 9keV. The delay time can be tailored to each particular experiment, with a nominal range of 70 - 350 fs for this prototype. The MEL-X, combined with established techniques such as x-ray diffraction, absorption or emission, could provide new insights on ultra-fast transitions in highly excited states of matter.

Coagulation sensors based on magnetostrictive delay lines for biomedical and chemical engineering applications

International Nuclear Information System (INIS)

Maliaritsi, E.; Zoumpoulakis, L.; Simitzis, J.; Vassiliou, P.; Hristoforou, E.

2006-01-01

Coagulation sensors based on the magnetostrictive delay line technique are presented in this paper. They are based on magnetostrictive ribbons and are used for measuring the coagulation, curing or solidification time of different liquids. Experimental results indicate that the presented sensing elements can determine the blood coagulation with remarkable repeatability, thus allowing their use as blood coagulation sensors. Additionally, results indicate that they can also measure curing time of resins, solidification of fluids and coagulation of chemical substances, therefore allowing their implementation in chemical engineering applications

Bio-Photonic Detection of Various Cellular Cultures

Science.gov (United States)

Hann, Patrick; Garzon, Maria; Pfeiffer, Erik; Lofland, Samuel; Knoesel, Ernst

2008-03-01

Since it is non-invasive, there has been increased research in the field of bio-optics. Many biological systems display an unusual phenomenon, delayed luminescence, produced by what is known as bio-photons. We present an apparatus and procedure for the detection of these ultra-weak photonic emissions using a single photon detection device. The results of bread yeast, saccramyces, and algae will be presented and compared to other reports in the literature

Quantum entanglement and phase transition in a two-dimensional photon-photon pair model

International Nuclear Information System (INIS)

Zhang Jianjun; Yuan Jianhui; Zhang Junpei; Cheng Ze

2013-01-01

We propose a two-dimensional model consisting of photons and photon pairs. In the model, the mixed gas of photons and photon pairs is formally equivalent to a two-dimensional system of massive bosons with non-vanishing chemical potential, which implies the existence of two possible condensate phases. Using the variational method, we discuss the quantum phase transition of the mixed gas and obtain the critical coupling line analytically. Moreover, we also find that the phase transition of the photon gas can be interpreted as enhanced second harmonic generation. We then discuss the entanglement between photons and photon pairs. Additionally, we also illustrate how the entanglement between photons and photon pairs can be associated with the phase transition of the system.

Control of operating parameters of laser ceilometers with the application of fiber optic delay line imitation

Science.gov (United States)

Kim, A. A.; Klochkov, D. V.; Konyaev, M. A.; Mihaylenko, A. S.

2017-11-01

The article considers the problem of control and verification of the laser ceilometers basic performance parameters and describes an alternative method based on the use of multi-length fiber optic delay line, simulating atmospheric track. The results of the described experiment demonstrate the great potential of this method for inspection and verification procedures of laser ceilometers.

Line defects on As2Se3-Chalcogenide photonic crystals for the design of all-optical power splitters and digital logic gates

Science.gov (United States)

Saghaei, Hamed; Zahedi, Abdulhamid; Karimzadeh, Rouhollah; Parandin, Fariborz

2017-10-01

In this paper, a triangular two-dimensional photonic crystal (PhC) of As2Se3-chalcogenide rods in air is presented and its photonic band diagram is calculated by plane wave method. In this structure, an optical waveguide is obtained by creating a line defect (eliminating rods) in diagonal direction of PhC. Numerical simulations based on finite difference time domain method show that when self-collimated beams undergo total internal reflection at the PhC-air interface, a total reflection of 90° occurs for the output beams. We also demonstrate that by decreasing the radius of As2Se3-chalcogenide instead of eliminating a diagonal line, a two-channel optical splitter will be designed. In this case, incoming self-collimated beams can be divided into the reflected and transmitted beams with arbitrary power ratio by adjusting the value of their radii. Based on these results, we propose a four-channel optical splitter using four line defects. The power ratio among output channels can be controlled systematically by varying the radius of rods in the line defects. We also demonstrate that by launching two optical sources with the same intensity and 90° phase difference from both perpendicular faces of the PhC, two logic OR and XOR gates will be achieved at the output channels. These optical devices have some applications in photonic integrated circuits for controlling and steering (managing) the light as desired.

Delayed luminescence to monitor programmed cell death induced by berberine on thyroid cancer cells

Science.gov (United States)

Scordino, Agata; Campisi, Agata; Grasso, Rosaria; Bonfanti, Roberta; Gulino, Marisa; Iauk, Liliana; Parenti, Rosalba; Musumeci, Francesco

2014-11-01

Correlation between apoptosis and UVA-induced ultraweak photon emission delayed luminescence (DL) from tumor thyroid cell lines was investigated. In particular, the effects of berberine, an alkaloid that has been reported to have anticancer activities, on two cancer cell lines were studied. The FTC-133 and 8305C cell lines, as representative of follicular and anaplastic thyroid human cancer, respectively, were chosen. The results show that berberine is able to arrest cell cycle and activate apoptotic pathway as shown in both cell lines by deoxyribonucleic acid fragmentation, caspase-3 cleavage, p53 and p27 protein overexpression. In parallel, changes in DL spectral components after berberine treatment support the hypothesis that DL from human cells originates mainly from mitochondria, since berberine acts especially at the mitochondrial level. The decrease of DL blue component for both cell lines could be related to the decrease of intra-mitochondrial nicotinamide adenine dinucleotide and may be a hallmark of induced apoptosis. In contrast, the response in the red spectral range is different for the two cell lines and may be ascribed to a different iron homeostasis.

Control of coherent information via on-chip photonic-phononic emitter-receivers.

Science.gov (United States)

Shin, Heedeuk; Cox, Jonathan A; Jarecki, Robert; Starbuck, Andrew; Wang, Zheng; Rakich, Peter T

2015-03-05

Rapid progress in integrated photonics has fostered numerous chip-scale sensing, computing and signal processing technologies. However, many crucial filtering and signal delay operations are difficult to perform with all-optical devices. Unlike photons propagating at luminal speeds, GHz-acoustic phonons moving at slower velocities allow information to be stored, filtered and delayed over comparatively smaller length-scales with remarkable fidelity. Hence, controllable and efficient coupling between coherent photons and phonons enables new signal processing technologies that greatly enhance the performance and potential impact of integrated photonics. Here we demonstrate a mechanism for coherent information processing based on travelling-wave photon-phonon transduction, which achieves a phonon emit-and-receive process between distinct nanophotonic waveguides. Using this device, physics--which supports GHz frequencies--we create wavelength-insensitive radiofrequency photonic filters with frequency selectivity, narrow-linewidth and high power-handling in silicon. More generally, this emit-receive concept is the impetus for enabling new signal processing schemes.

Magnon-photon interaction in ferromagnets

International Nuclear Information System (INIS)

Shrivastava, K.N.

1980-01-01

A magnon-photon interaction for the magnetic vector of the electromagnetic wave perpendicular to the direction of magnetization in a ferromagnet is constructed with the use of Bogoliubov transformation. The resulting magnon-photon interaction is found to contain several interesting new radiation effects. The self-energy of the magnon is calculated and life times arising from the radiation scattering are predicted. The magnon frequency shift due to the radiation field is found. One of the terms arising from the one-magnon one-photon scattering gives a line width that is in reasonable agreement with the experimentally measured value of ferromagnetic resonance line width in yttrium iron garnet. (orig.)

Myocardial delayed-enhancement CT: initial experience in children and young adults

Energy Technology Data Exchange (ETDEWEB)

Goo, Hyun Woo [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of)

2017-10-15

Clinical utility of myocardial delayed enhancement CT has not been reported in children and young adults. To describe initial experience of myocardial delayed enhancement CT regarding image quality, radiation dose and identification of myocardial lesions in children and young adults. Between August 2013 and November 2016, 29 consecutive children and young adults (median age 16 months) with suspected coronary artery or myocardial abnormality underwent arterial- and delayed-phase cardiac CT at our institution. We measured CT densities in normal myocardium, left ventricular cavity, and arterial and delayed hypo-enhancing and delayed hyperenhancing myocardial lesions. We then compared the extent of delayed hyperenhancing lesions with delayed-enhancement MRI or thallium single-photon emission CT. Normal myocardium and left ventricular cavity showed significantly higher CT numbers on arterial-phase CT than on delayed-phase CT (t-test, P<0.0001). Contrast-to-noise ratios of the arterial and delayed hypo-enhancing and delayed hyperenhancing lesions on CT were 26.7, 17.6 and 18.7, respectively. Delayed-phase CT findings were equivalent to those of delayed-enhancement MRI in all cases (7/7) and to those of thallium single-photon emission CT in 70% (7/10). Myocardial delayed-enhancement CT can be added to evaluate myocardial lesions in select children and young adults with suspected coronary artery or myocardial abnormality. (orig.)

Myocardial delayed-enhancement CT: initial experience in children and young adults

International Nuclear Information System (INIS)

Goo, Hyun Woo

2017-01-01

Clinical utility of myocardial delayed enhancement CT has not been reported in children and young adults. To describe initial experience of myocardial delayed enhancement CT regarding image quality, radiation dose and identification of myocardial lesions in children and young adults. Between August 2013 and November 2016, 29 consecutive children and young adults (median age 16 months) with suspected coronary artery or myocardial abnormality underwent arterial- and delayed-phase cardiac CT at our institution. We measured CT densities in normal myocardium, left ventricular cavity, and arterial and delayed hypo-enhancing and delayed hyperenhancing myocardial lesions. We then compared the extent of delayed hyperenhancing lesions with delayed-enhancement MRI or thallium single-photon emission CT. Normal myocardium and left ventricular cavity showed significantly higher CT numbers on arterial-phase CT than on delayed-phase CT (t-test, P<0.0001). Contrast-to-noise ratios of the arterial and delayed hypo-enhancing and delayed hyperenhancing lesions on CT were 26.7, 17.6 and 18.7, respectively. Delayed-phase CT findings were equivalent to those of delayed-enhancement MRI in all cases (7/7) and to those of thallium single-photon emission CT in 70% (7/10). Myocardial delayed-enhancement CT can be added to evaluate myocardial lesions in select children and young adults with suspected coronary artery or myocardial abnormality. (orig.)

Compton scattering of photons from electrons in magnetically insulated transmission lines

International Nuclear Information System (INIS)

Brower, K.L.; VanDevender, J.P.

1979-01-01

Self-magnetically insulated transmission lines are used for power transport between the vacuum insulator and the diode in high current particle accelerators. Since the efficiency of the power transport depends on the details of the initial line geometry, i.e., the injector, the dependence of the electron canonical momentum distribution on the injector geometry should reveal the loss mechanism. We propose to study that dependence experimentally through a Compton scattering diagnostic. The spectrum of scattered light reveals the electron velocity distribution perpendicular to the direction of flow. The design of the diagnostic is in progress. Our preliminary analysis is based on the conservation of energy and canonical momentum for a single electron in the anti E and anti B fields determined from 2-D calculations. For the Mite accelerator with power flow along Z, the normalized canonical momentum, μ, is in the range - 0.7 < μ less than or equal to 0. For anti k/sub i/ parallel to circumflex Y, and anti k/sub s/ circumflex X, our analysis indicates that the scattered photons have 1.1 eV less than or equal to h nu/sub s/ < 5.6 eV for ruby laser scattering and can be detected with PM tubes

Bio-Photons of Various Cellular Cultures and Tissues

Science.gov (United States)

Hann, Patrick; Knoesel, Ernst; Garzon, Maria; Lofland, Samuel; Pfieffer, Erik

2008-04-01

Since it is non-invasive, there has been increased research in the field of bio-optics. Many biological systems display an unusual phenomenon, delayed luminescence, produced by what is known as bio-photons. We present an apparatus and procedure for the detection of these ultra-weak photonic emissions using a single photon detection device. The results of bread yeast, saccramyces, and algae will be presented and compared to other reports in the literature.

Search for Long-Lived Neutral Particles in Final states with Delayed Photon and Missing Transverse Energy from Proton-Proton Collisions using the CMS detector

CERN Document Server

AUTHOR|(CDS)2080019; Kubota, Yuichi; Kao, Shih-Chuan; Kubota, Yuichi

2016-12-01

We perform a search for long-lived neutral particles in final state with delayed photons and large missing transverse energy produced in LHC proton-proton collisions at center-of-mass energy, $\\sqrt{s} = 8\\TeV$. Capitalizing on the excellent timing resolution of the CMS Electromagnetic Calorimeter the search uses photon time measurements made by the Electromagnetic Calorimeter as the main search quantity. We found a single event consistent with our background expectations from the Standard Model and set a model-independent upper limit of 4.37 on number of signal events. We also interpret our results in the context of the SPS8 benchmark GMSB model and show that neutralinos with mean lifetime, $\\tau \\leq 45$ns, and mass, $m \\leq 300\\GeV/c^{2}$, or effective Supersymmetry breaking energy scale, $\\Lambda \\leq 220\\TeV$, are ruled out of existence at 95% $CL_{S}$ confidence level. The exclusion limit on the product of the production cross-section and branching ratio of the neutralino to photon and gravitino decay ...

Temporal dynamics of all-optical switching in Photonic Crystal Cavity

DEFF Research Database (Denmark)

Colman, Pierre; Heuck, Mikkel; Yu, Yi

2014-01-01

The temporal dynamics of all-optical switching has been investigated in a Photonic Crystal Cavity with a 150fs-40aJ/pulse resolution. This allowed observing for the first time effects like pulse reshaping, pulse delay and intra-cavity Four-Wave-Mixing.......The temporal dynamics of all-optical switching has been investigated in a Photonic Crystal Cavity with a 150fs-40aJ/pulse resolution. This allowed observing for the first time effects like pulse reshaping, pulse delay and intra-cavity Four-Wave-Mixing....

Delay-Range-Dependent H∞ Control for Automatic Mooring Positioning System with Time-Varying Input Delay

Directory of Open Access Journals (Sweden)

Xiaoyu Su

2014-01-01

Full Text Available Aiming at the economy and security of the positioning system in semi-submersible platform, the paper presents a new scheme based on the mooring line switching strategy. Considering the input delay in switching process, H∞ control with time-varying input delay is designed to calculate the control forces to resist disturbing forces. In order to reduce the conservativeness, the information of the lower bound of delay is taken into account, and a Lyapunov function which contains the range of delay is constructed. Besides, the input constraint is considered to avoid breakage of mooring lines. The sufficient conditions for delay-range-dependent stabilization are derived in terms of LMI, and the controller is also obtained. The effectiveness of the proposed approach is illustrated by a realistic design example.

Insertion device and beam line plans for the Advanced Photon Source: A report and recommendations by the Insertion Device and Beam Line Planning Committee

International Nuclear Information System (INIS)

1988-02-01

In the 7-GeV Advanced Photon Source (APS) Conceptual Design Report (CDR), fifteen complete experimental beam lines were specified in order to establish a representative technical and cost base for the components involved. In order to optimize the composition of the insertion devices and the beam line, these funds are considered a ''Trust Fund.'' The present report evaluates the optimization for the distribution of these funds so that the short- and long-term research programs will be most productive, making the facility more attractive from the user's point of view. It is recommended that part of the ''Trust Fund'' be used for the construction of the insertion devices, the front-end components, and the first-optics, minimizing the cost to potential users of completing a beam line. In addition, the possibility of cost savings resulting from replication and standardization of high multiplicity components (such as IDs, front ends, and first-optics instrumentation) is addressed. 2 refs., 5 tabs

Collision-induced stimulated photon echo generated at transition 0-1 on broad spectral line conditions

Science.gov (United States)

Rubtsova, N. N.; Gol'dort, V. G.; Ishchenko, V. N.; Khvorostov, E. B.; Kochubei, S. A.; Borisov, G. M.; Ledovskikh, D. V.; Reshetov, V. A.

2018-04-01

For the first time, the collision induced stimulated photon echo generated at transition 1S0 → 3 P1 of 174Yb (type 0-1) in the mixture of gases Yb  +  Xe was investigated in the presence of weak longitudinal magnetic field, with experimental parameters corresponding to broad spectral line conditions. Comparison of the experimental echo amplitude versus magnetic field strength dependence with the theoretical curve shows a very good agreement, giving rise to an improved estimate for the difference between alignment and orientation decay rates.

In-line microfluidic refractometer based on C-shaped fiber assisted photonic crystal fiber Sagnac interferometer.

Science.gov (United States)

Wu, Chuang; Tse, Ming-Leung Vincent; Liu, Zhengyong; Guan, Bai-Ou; Lu, Chao; Tam, Hwa-Yaw

2013-09-01

We propose and demonstrate a highly sensitive in-line photonic crystal fiber (PCF) microfluidic refractometer. Ultrathin C-shaped fibers are spliced in-between the PCF and standard single-mode fibers. The C-shaped fibers provide openings for liquid to flow in and out of the PCF. Based on a Sagnac interferometer, the refractive index (RI) response of the device is investigated theoretically and experimentally. A high sensitivity of 6621 nm/RIU for liquid RI from 1.330 to 1.333 is achieved in the experiment, which agrees well with the theoretical analysis.

Liquid Crystal photonic Bandgap Fiber Devices

DEFF Research Database (Denmark)

Wei, Lei

In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure. The prese......In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure...... of each LCPBG fiber. Finally, the applications for LCPBG fiber devices based on the on-chip platform design have been demonstrated in realizing microwave true-time delay and creating an electrically tunable fiber laser. Referatet mailes...

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

DEFF Research Database (Denmark)

Nielsen, Marie Kristina Rue; Chakera, Annette H; Hesse, Birger

2011-01-01

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.......The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients....

gPhoton: THE GALEX PHOTON DATA ARCHIVE

Energy Technology Data Exchange (ETDEWEB)

Million, Chase [Million Concepts LLC, P.O. Box 119, 141 Mary Street, Lemont, PA 16851 (United States); Fleming, Scott W.; Shiao, Bernie; Smith, Myron; Thompson, Randy; White, Richard L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seibert, Mark [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Loyd, Parke [Laboratory for Atmospheric and Space Physics, Boulder, Colorado, 80309 (United States); Tucker, Michael [Dept. of Physics and Astronomy, Appalachian State University, Boone, NC 28608 (United States)

2016-12-20

gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project’s stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope. This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command-line modules serve as a front end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database, and tools, with emphasis on divergence from prior work, as well as challenges created by the large data volume. We summarize the astrometric and photometric performance of gPhoton relative to the original mission pipeline. For a brief example of short time-domain science capabilities enabled by gPhoton, we show new flares from the known M-dwarf flare star CR Draconis. The gPhoton software has permanent object identifiers with the ASCL (ascl:1603.004) and DOI (doi:10.17909/T9CC7G). This paper describes the software as of version v1.27.2.

Femtosecond Pulse Characterization as Applied to One-Dimensional Photonic Band Edge Structures

Science.gov (United States)

Fork, Richard L.; Gamble, Lisa J.; Diffey, William M.

1999-01-01

The ability to control the group velocity and phase of an optical pulse is important to many current active areas of research. Electronically addressable one-dimensional photonic crystals are an attractive candidate to achieve this control. This report details work done toward the characterization of photonic crystals and improvement of the characterization technique. As part of the work, the spectral dependence of the group delay imparted by a GaAs/AlAs photonic crystal was characterized. Also, a first generation an electrically addressable photonic crystal was tested for the ability to electronically control the group delay. The measurement technique, using 100 femtosecond continuum pulses was improved to yield high spectral resolution (1.7 nanometers) and concurrently with high temporal resolution (tens of femtoseconds). Conclusions and recommendations based upon the work done are also presented.

Sensitivity of entangled photon holes to loss and amplification

Energy Technology Data Exchange (ETDEWEB)

Franson, J. D. [Physics Department, University of Maryland, Baltimore County, Baltimore, Maryland 21250 (United States)

2011-10-15

Energy-time entangled photon holes are shown to be relatively insensitive to photon loss due to absorption by atoms whose coherence times are longer than the time delays typically employed in nonlocal interferometry (a fraction of a nanosecond). Roughly speaking, the excited atoms do not retain any significant ''which-path'' information regarding the time at which a photon was absorbed. High-intensity entangled photon holes can also be amplified under similar conditions. Decoherence does occur from losses at beam splitters, and these results show that photon loss cannot always be adequately modeled using a sequence of beam splitters. These properties of entangled photon holes may be useful in quantum communications systems where the range of the system is limited by photon loss.

One-bit photon polarization in two-photon experiments. An information mechanics perspective

International Nuclear Information System (INIS)

Kantor, F.W.

1991-01-01

In this paper is presented a detailed treatment of amount and representation of photon polarization information in the two-photon experiments of Aspect, Grangier, and Roger, seeking to test Einstein, Podolsky, and Rosen's thought experiment. Newton's mechanics, Einstein's relativistic mechanics, and quantum mechanics do not treat as fundamental the amount and representation of information in physical systems. The line of reasoning presented here was reached via Kantor's information mechanics. The information bookkeeping presented here appears to offer a simple, physical insight into what the apparatus and the photons are doing together

Positronium-photon and photon-positronium quantum transitions in strong magnetic fields

International Nuclear Information System (INIS)

Leinson, L.B.; Oraevskii, V.N.; Radio-Wave Propagation, Academy of Sciences of the USSR)

1985-01-01

The wave functions and energy levels of bound electron-positron pairs in a strong magnetic field H>>α 2 H 0 , where H 0 = m 2 0 c 3 /eh = 4.4 x 10 13 G and α = e 2 /hc, are found in the nonrelativistic approximation. The probabilities of one-photon annihilation of positronium and of the inverse transition from a resonance photon to a positronium atom are calculated. It is shown that in a sufficiently strong magnetic field H∼H 0 , when the probability of one-photon annihilation is considerably greater than the probability of two-photon annihilation of positronium, the lifetime of the decay photon with respect to the inverse transformation to a positronium atom is so small that the decay photon cannot propagate freely in the magnetic field. Therefore, the lifetime of the positronium atom in the case H∼H 0 is determined by the two-photon decay. The possibility of the decay γ→γ 1 +γ 2 via intermediate positronium states in a magnetic field with curved field lines is discussed

200-MeV bremsstrahlung tagged photon beams at Sendai

International Nuclear Information System (INIS)

Hirose, K.; Chiba, M.; Inoue, M.; Kanda, H.; Kimura, R.; Kino, K.; Kobayashi, Y.; Konno, O.; Maeda, K.; Miyase, H.; Miyamoto, A.; Ohtsuki, T.; Saito, A.; Suda, T.; Takahashi, K.; Tamae, T.; Terasaki, Y.; Terasawa, T.; Tsubota, H.; Tsuruta, T.; Utoyama, M.; Yuuki, H.; Yamaguchi, Y.; Yamazaki, H.

2006-01-01

A new beam line for photonuclear reaction experiments using tagged photons has been constructed to take advantage of the completion of the 1.2-GeV STretcher Booster (STB) ring at the Laboratory of Nuclear Science (LNS), Tohoku University. A photon tagging system was installed at the end of the new beam line. It provides bremsstrahlung tagged photon beams in an energy range from 0.2E 0 to 0.8E 0 MeV at the incident electron energy E 0 with an energy resolution of ΔE/E∼10 -2 . The tagged photon intensity I= 6 photons/s is available for typical photonuclear reaction experiments. We introduce the basic parameters of the tagged photons by showing the commissioning data

On-chip photonic-phononic emitter-receiver apparatus

Science.gov (United States)

Cox, Jonathan Albert; Jarecki, Jr., Robert L.; Rakich, Peter Thomas; Wang, Zheng; Shin, Heedeuk; Siddiqui, Aleem; Starbuck, Andrew Lea

2017-07-04

A radio-frequency photonic devices employs photon-phonon coupling for information transfer. The device includes a membrane in which a two-dimensionally periodic phononic crystal (PnC) structure is patterned. The device also includes at least a first optical waveguide embedded in the membrane. At least a first line-defect region interrupts the PnC structure. The first optical waveguide is embedded within the line-defect region.

Hybrid Active-Passive Microwave Photonic Filter with High Quality Factor

International Nuclear Information System (INIS)

En-Ming, Xu; Xin-Liang, Zhang; Li-Na, Zhou; Yu, Zhang; De-Xiu, Huang

2009-01-01

A hybrid high quality factor (Q-factor) microwave photonic filter with a cascaded active filter and a passive filter is presented and experimentally demonstrated. The active infinite impulse response filter is realized by a recirculating delay line loop with a semiconductor optical amplifier, and a much narrower 3 dB bandwidth of response peaks can be achieved. A passive finite impulse response filter is realized by an unbalance Mach–Zehnder interferometer, and it is cascaded to select the desired filter frequencies and to suppress the intermediate peaks. Compared with the purely active filter scheme, the free spectrum range and the Q-factor of the hybrid structure can be doubled. Stable operation and a high Q-factor of 362 are experimentally demonstrated

Galactic Shapiro delay to the Crab pulsar and limit on weak equivalence principle violation

Energy Technology Data Exchange (ETDEWEB)

Desai, Shantanu [Indian Institute of Technology, Department of Physics, Hyderabad, Telangana (India); Kahya, Emre [Istanbul Technical University, Department of Physics, Istanbul (Turkey)

2018-02-15

We calculate the total galactic Shapiro delay to the Crab pulsar by including the contributions from the dark matter as well as baryonic matter along the line of sight. The total delay due to dark matter potential is about 3.4 days. For baryonic matter, we included the contributions from both the bulge and the disk, which are approximately 0.12 and 0.32 days respectively. The total delay from all the matter distribution is therefore 3.84 days. We also calculate the limit on violations of Weak equivalence principle by using observations of ''nano-shot'' giant pulses from the Crab pulsar with time-delay < 0.4 ns, as well as using time differences between radio and optical photons observed from this pulsar. Using the former, we obtain a limit on violation of Weak equivalence principle in terms of the PPN parameter Δγ < 2.41 x 10{sup -15}. From the time-difference between simultaneous optical and radio observations, we get Δγ < 1.54 x 10{sup -9}. We also point out differences in our calculation of Shapiro delay and that from two recent papers (Yang and Zhang, Phys Rev D 94(10):101501, 2016; Zhang and Gong, Astrophys J 837:134, 2017), which used the same observations to obtain a corresponding limit on Δγ. (orig.)

Galactic Shapiro delay to the Crab pulsar and limit on weak equivalence principle violation

International Nuclear Information System (INIS)

Desai, Shantanu; Kahya, Emre

2018-01-01

We calculate the total galactic Shapiro delay to the Crab pulsar by including the contributions from the dark matter as well as baryonic matter along the line of sight. The total delay due to dark matter potential is about 3.4 days. For baryonic matter, we included the contributions from both the bulge and the disk, which are approximately 0.12 and 0.32 days respectively. The total delay from all the matter distribution is therefore 3.84 days. We also calculate the limit on violations of Weak equivalence principle by using observations of ''nano-shot'' giant pulses from the Crab pulsar with time-delay < 0.4 ns, as well as using time differences between radio and optical photons observed from this pulsar. Using the former, we obtain a limit on violation of Weak equivalence principle in terms of the PPN parameter Δγ < 2.41 x 10 -15 . From the time-difference between simultaneous optical and radio observations, we get Δγ < 1.54 x 10 -9 . We also point out differences in our calculation of Shapiro delay and that from two recent papers (Yang and Zhang, Phys Rev D 94(10):101501, 2016; Zhang and Gong, Astrophys J 837:134, 2017), which used the same observations to obtain a corresponding limit on Δγ. (orig.)

Photonic single nonlinear-delay dynamical node for information processing

Science.gov (United States)

Ortín, Silvia; San-Martín, Daniel; Pesquera, Luis; Gutiérrez, José Manuel

2012-06-01

An electro-optical system with a delay loop based on semiconductor lasers is investigated for information processing by performing numerical simulations. This system can replace a complex network of many nonlinear elements for the implementation of Reservoir Computing. We show that a single nonlinear-delay dynamical system has the basic properties to perform as reservoir: short-term memory and separation property. The computing performance of this system is evaluated for two prediction tasks: Lorenz chaotic time series and nonlinear auto-regressive moving average (NARMA) model. We sweep the parameters of the system to find the best performance. The results achieved for the Lorenz and the NARMA-10 tasks are comparable to those obtained by other machine learning methods.

Elimination of residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy using an optical fiber delay line.

Science.gov (United States)

Chakraborty, Arup Lal; Ruxton, Keith; Johnstone, Walter; Lengden, Michael; Duffin, Kevin

2009-06-08

A new fiber-optic technique to eliminate residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy is presented. The modulated laser output is split to pass in parallel through the gas measurement cell and an optical fiber delay line, with the modulation frequency / delay chosen to introduce a relative phase shift of pi between them. The two signals are balanced using a variable attenuator and recombined through a fiber coupler. In the absence of gas, the direct laser intensity modulation cancels, thereby eliminating the high background. The presence of gas induces a concentration-dependent imbalance at the coupler's output from which the absolute absorption profile is directly recovered with high accuracy using 1f detection.

Fano resonance in anodic aluminum oxide based photonic crystals.

Science.gov (United States)

Shang, Guo Liang; Fei, Guang Tao; Zhang, Yao; Yan, Peng; Xu, Shao Hui; Ouyang, Hao Miao; Zhang, Li De

2014-01-08

Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.

Using Quasars as Standard Candles for Studying Dark Energy

DEFF Research Database (Denmark)

Denney, Kelly D.; Vestergaard, Marianne; Watson, D.

2012-01-01

, which relies on the technique of reverberation mapping to measure time delays between the quasar continuum and emission line variability signatures. Measuring this time delay effectively measures the radius between the central source and the emission-line gas. The emission line gas is photo-ionized...... by the continuum photons, and the radius to this emission-line region scales tightly with the nuclear luminosity - a consequence of the photoionization physics responsible for regulating the production of line-emitting photons. Hence, measuring the radius of the emission-line gas provides a measure...

Irradiation combined with SU5416: Microvascular changes and growth delay in a human xenograft glioblastoma tumor line

International Nuclear Information System (INIS)

Schuuring, Janneke; Bussink, Johan; Bernsen, Hans; Peeters, Wenny; Kogel, Albert J. van der

2005-01-01

Purpose: The combination of irradiation and the antiangiogenic compound SU5416 was tested and compared with irradiation alone in a human glioblastoma tumor line xenografted in nude mice. The aim of this study was to monitor microenvironmental changes and growth delay. Methods and materials: A human glioblastoma xenograft tumor line was implanted in nude mice. Irradiations consisted of 10 Gy or 20 Gy with and without SU5416. Several microenvironmental parameters (tumor cell hypoxia, tumor blood perfusion, vascular volume, and microvascular density) were analyzed after imunohistochemical staining. Tumor growth delay was monitored for up to 200 days after treatment. Results: SU5416, when combined with irradiation, has an additive effect over treatment with irradiation alone. Analysis of the tumor microenvironment showed a decreased vascular density during treatment with SU5416. In tumors regrowing after reaching only a partial remission, vascular characteristics normalized shortly after cessation of SU5416. However, in tumors regrowing after reaching a complete remission, permanent microenvironmental changes and an increase of tumor necrosis with a subsequent slower tumor regrowth was found. Conclusions: Permanent vascular changes were seen after combined treatment resulting in complete remission. Antiangiogenic treatment with SU5416 when combined with irradiation has an additive effect over treatment with irradiation or antiangiogenic treatment alone

Mass distribution for the two-photon channel

CERN Multimedia

ATLAS, collaboration

2012-01-01

Mass distribution for the two-photon channel. The strongest evidence for this new particle comes from analysis of events containing two photons. The smooth dotted line traces the measured background from known processes. The solid line traces a statistical fit to the signal plus background. The new particle appears as the excess around 126.5 GeV. The full analysis concludes that the probability of such a peak is three chances in a million.

High-Speed Photonic Reservoir Computing Using a Time-Delay-Based Architecture: Million Words per Second Classification

Directory of Open Access Journals (Sweden)

Laurent Larger

2017-02-01

Full Text Available Reservoir computing, originally referred to as an echo state network or a liquid state machine, is a brain-inspired paradigm for processing temporal information. It involves learning a “read-out” interpretation for nonlinear transients developed by high-dimensional dynamics when the latter is excited by the information signal to be processed. This novel computational paradigm is derived from recurrent neural network and machine learning techniques. It has recently been implemented in photonic hardware for a dynamical system, which opens the path to ultrafast brain-inspired computing. We report on a novel implementation involving an electro-optic phase-delay dynamics designed with off-the-shelf optoelectronic telecom devices, thus providing the targeted wide bandwidth. Computational efficiency is demonstrated experimentally with speech-recognition tasks. State-of-the-art speed performances reach one million words per second, with very low word error rate. Additionally, to record speed processing, our investigations have revealed computing-efficiency improvements through yet-unexplored temporal-information-processing techniques, such as simultaneous multisample injection and pitched sampling at the read-out compared to information “write-in”.

Organic membrane photonic integrated circuits (OMPICs).

Science.gov (United States)

Amemiya, Tomohiro; Kanazawa, Toru; Hiratani, Takuo; Inoue, Daisuke; Gu, Zhichen; Yamasaki, Satoshi; Urakami, Tatsuhiro; Arai, Shigehisa

2017-08-07

We propose the concept of organic membrane photonic integrated circuits (OMPICs), which incorporate various functions needed for optical signal processing into a flexible organic membrane. We describe the structure of several devices used within the proposed OMPICs (e.g., transmission lines, I/O couplers, phase shifters, photodetectors, modulators), and theoretically investigate their characteristics. We then present a method of fabricating the photonic devices monolithically in an organic membrane and demonstrate the operation of transmission lines and I/O couplers, the most basic elements of OMPICs.

Energy flow in photonic crystal waveguides

DEFF Research Database (Denmark)

Søndergaard, Thomas; Dridi, Kim

2000-01-01

Theoretical and numerical investigations of energy flow in photonic crystal waveguides made of line defects and branching points are presented. It is shown that vortices of energy flow may occur, and the net energy flow along: the line defect is described via the effective propagation velocity....... Single-mode and multimode operations are studied, and dispersion relations are computed for different waveguide widths. Both strong positive, strong negative, and zero dispersion an possible. It is shown that geometric parameters such as the nature of the lattice, the line defect orientation, the defect...... width, and the branching-point geometry have a significant influence on the electrodynamics. These are important issues for the fabrication of photonic crystal structures....

In-line photonic microcells based on the elliptical microfibers for refractive index sensors applications

Science.gov (United States)

Jin, Wa; Liu, Xuejing; Jin, Wei

2017-10-01

We report the fabrication of in-line photonic microcells (PMCs) by encapsulating tapered elliptical microfibers (MFs) inside glass tubes. The encapsulation does not change the optical property of the MF but protects the elliptical MF from external disturbance and contamination and makes the micro-laboratory robust. Such micro-laboratory can be easily integrated into standard fiber-optic circuits with low loss, making the elliptical MF-based devices more practical for real-world applications. Evanescent field sensing is realized by fabricating micro-channel on the PMC for ingress/egress of sample liquids/gas. Based on the encapsulated elliptical MF PMCs, we demonstrated RI sensitivity of 2024 nm per refractive index unit (nm/RIU) in gaseous environment and 21231 nm/RIU in water.

A Design of First-Order Delay-Line DPLL in 1.2μm CMOS Technology

OpenAIRE

Seki, Ikuo; Nakashi, Kenichi; Ushida, Mitsuhiko; Taniguchi, Kenji

1996-01-01

This paper describes a CMOS 1st-order delay-line DPLL in l.2μm technology for clock regeneration. We have employed a parallel-architecture PC (Phase Comparator) to improve the speed and a DCO (Digitally Controlled Oscillator) without timing hazard. And we have also laid it out in 1.2μm CMOS, and simulated its performance by SPICE as well as logic simulation. Results show that the DPLL operates up to 60MHz, and that lock-in ranges are +5/-5% for regular" 10" input and +5/-5% for 2^13-1 PRBS (P...

Subsurface Scattered Photons: Friend or Foe? Improving visible light laser altimeter elevation estimates, and measuring surface properties using subsurface scattered photons

Science.gov (United States)

Greeley, A.; Kurtz, N. T.; Neumann, T.; Cook, W. B.; Markus, T.

2016-12-01

Photon counting laser altimeters such as MABEL (Multiple Altimeter Beam Experimental Lidar) - a single photon counting simulator for ATLAS (Advanced Topographical Laser Altimeter System) - use individual photons with visible wavelengths to measure their range to target surfaces. ATLAS, the sole instrument on NASA's upcoming ICESat-2 mission, will provide scientists a view of Earth's ice sheets, glaciers, and sea ice with unprecedented detail. Precise calibration of these instruments is needed to understand rapidly changing parameters such as sea ice freeboard, and to measure optical properties of surfaces like snow covered ice sheets using subsurface scattered photons. Photons that travel through snow, ice, or water before scattering back to an altimeter receiving system travel farther than photons taking the shortest path between the observatory and the target of interest. These delayed photons produce a negative elevation bias relative to photons scattered directly off these surfaces. We use laboratory measurements of snow surfaces using a flight-tested laser altimeter (MABEL), and Monte Carlo simulations of backscattered photons from snow to estimate elevation biases from subsurface scattered photons. We also use these techniques to demonstrate the ability to retrieve snow surface properties like snow grain size.

Photon interrogation for bulk measurement of transuranic materials

International Nuclear Information System (INIS)

Nieschmidt, E.B.

1981-01-01

Investigation and assay of high atomic number materials may be accomplished in near real-time through use of photon interrogation. Photon interrogation, as used here, involves the use of high-energy photons to induce fission and then detect neutrons associated with the fission. This technique has the advantage that the interrogating particle and the detected particle are different. The discussion here will include: (1) neutron production; (2) photon production; (3) neutron counting; (4) sensitivity; and (5) problems associated with large containers. In summary, the attributes and limitations of photon interrogation can be stated as: near real-time accountability; interrogating particle different than detected particle; ability to count prompt or delayed neutrons depending on matrix; radiography or therapy accelerators available; cannot distinguish between fission and fertile material; and interrogated material must be well characterized to obtain safeguards quality results

Development of an X-ray delay unit for correlation spectroscopy and pump-probe experiments

Energy Technology Data Exchange (ETDEWEB)

Roseker, Wojciech

2008-07-15

Probing condensed matter on time scales ranging from femtoseconds to nanoseconds will be one of the key topics for future X-ray Free Electron Laser (XFEL) sources. The accessible time windows are, however, compromised by the intrinsic time structure of the sources. One way to overcome this limitation is the usage of a time delay unit. A prototype device capable of splitting an X-ray pulse into two adjustable fractions, delaying one of them with the aim to perform X-ray Photon Correlation Spectroscopy and pump-probe type studies was designed and manufactured. The device utilizes eight perfect crystals in vertical 90 scattering geometry. Its performance has been verified with 8.39 keV and 12.4 keV Xrays at various synchrotron sources. The measured throughput of the device with a Si(333) monochromator at 8.39 keV under ambient conditions is 0.6%. The stability was verified at 12.4 keV and operation without realignment and feedback was possible for more than 30 minutes. Time delays up to 2.95 ns have been achieved. The highest resolution achieved in an experiment was 15.4 ps, a value entirely determined by the diagnostics system. The influence of the delay unit optics on the coherence properties of the beam was investigated by means of Fraunhofer diffraction and static speckle analysis. The obtained high fringe visibility and contrast values larger than 23% indicate the feasibility of performing coherence based experiments with the delay line. (orig.)

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals

DEFF Research Database (Denmark)

Pedersen, Martin Erland Vestergaard; Rishøj, Lars Søgaard; Steffensen, Henrik

2007-01-01

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals is theoretically studied. Using a scattering-matrix approach and the Wigner–Smith delay time concept, we show that optical absorbance benefits both from slow-light phenomena as well as a high filling factor of the energy...... residing in the liquid. Utilizing strongly dispersive photonic crystal structures, we numerically demonstrate how liquid-infiltrated photonic crystals facilitate enhanced light–matter interactions, by potentially up to an order of magnitude. The proposed concept provides strong opportunities for improving...

Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

Energy Technology Data Exchange (ETDEWEB)

Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-08-01

Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers.

Science.gov (United States)

Chin, Sanghoon; Thévenaz, Luc; Sancho, Juan; Sales, Salvador; Capmany, José; Berger, Perrine; Bourderionnet, Jérôme; Dolfi, Daniel

2010-10-11

We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters.

Search for Long-Lived Neutral Particles in Final States with Delayed Photon and Missing Transverse Energy from Proton-Proton Collisions Using the CMS detector

Science.gov (United States)

Tambe Ebai, Norbert

We perform a search for long-lived neutral particles in final state with delayed photons and large missing transverse energy produced in LHC proton-proton collisions at center-of-mass energy, √s = 8 TeV. Capitalizing on the excellent timing resolution of the CMS Electromagnetic Calorimeter the search uses photon time measurements made by the Electromagnetic Calorimeter as the main search quantity. We found a single event consistent with our background expectations from the Standard Model and set a model-independent upper limit of 4.37 on number of signal events. We also interpret our results in the context of the SPS8 benchmark GMSB model and show that neutralinos with mean lifetime, tau PSneutralinoOne ≤ 45 ns, and mass, mPSneutralinoOne ≤ 300 GeV/c2, or effective Supersymmetry breaking energy scale, Lambda ≤ 220TeV, are ruled out of existence at 95% CLS confidence level. The exclusion limit on the product of the production cross-section and branching ratio of the neutralino to photon and gravitino decay channel, sigma(PSneutralinoOne → gamma + G˜) x BR, for different lifetimes and masses is derived. Our results confirm for the first time that the CMS Electromagnetic Calorimeter provides good sensitivity to search for long-lived neutral particles with lifetimes up to 40 ns and masses up to 300 GeV/c2 using only timing measurements.

Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

Science.gov (United States)

Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.

2010-03-01

We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).

Wavelength-stepped, actively mode-locked fiber laser based on wavelength-division-multiplexed optical delay lines

Science.gov (United States)

Lee, Eunjoo; Kim, Byoung Yoon

2017-12-01

We propose a new scheme for an actively mode-locked wavelength-swept fiber laser that produces a train of discretely wavelength-stepped pulses from a short fiber cavity. Pulses with different wavelengths are split and combined by standard wavelength division multiplexers with fiber delay lines. As a proof of concept, we demonstrate a laser using an erbium doped fiber amplifier and commercially available wavelength-division multiplexers with wavelength spacing of 0.8 nm. The results show simultaneous mode-locking at three different wavelengths. Laser output parameters in time domain, optical and radio frequency spectral domain, and the noise characteristics are presented. Suggestions for the improved design are discussed.

Computer simulation of Wheeler's delayed-choice experiment with photons

NARCIS (Netherlands)

Zhao, S.; Yuan, S.; De Raedt, H.; Michielsen, K.

We present a computer simulation model of Wheeler's delayed-choice experiment that is a one-to-one copy of an experiment reported recently (Jacques V. et al., Science, 315 (2007) 966). The model is solely based on experimental facts, satisfies Einstein's criterion of local causality and does not

Vitamin E analogue, D-alpha tocopherol succinate, enhances x-ray induced growth delay of human adenocarcinoma cancer cell line

International Nuclear Information System (INIS)

Jaworska, A.; Ottesen, T.E.

2003-01-01

The purpose of this study was to assess the effects of d-alpha Tocopherol succinate (alpha-TS) in modifying radiation-induced viability reduction and apoptosis occurrence in the model for normal and cancer cells. Our hypothesis was that alpha-TS enhances the growth-inhibitory effect of x-irradiation in cancer cells and that the effect is more pronounced in these cells than in normal cells. Murine NIH 3T3 Swiss albino embryonic cells and HT29 human Caucasian colon adenocarcinoma cells were used in the experiments. Alpha-TS was added to the cultures 1 h prior to irradiation with doses of 2 or 5Gy of x-ray. After irradiation cells were incubated for 73 h. Trypan blue exclusion viability test and estimation of apoptosis and necrosis were made. Apoptotic and necrotic cells were counted in fluorescence microscope using fluorescence dyes: propidium iodide and Hoechst 33342. For experiments with the dose of 5 Gy at least five series of experiments were performed. At lower doses (up to approximately 25μM/ml) treatment with alpha-TS alone enhanced growth of both cell lines. At higher doses treatment with alpha-TS alone delayed the growth of the cell cultures, accompanied by 20-25% necrosis. At the concentrations higher than 25μM/mL alpha-TS alone caused growth delay of both cell cultures, being much more pronounced for the cancer cell line HT29. At the concentrations of 50 μM/mL, responsible for about 30-60% of growth delay, there was observed a synergy effect for x-rays and alpha-TS for both cell lines. The effect was more pronounced for HT29 cells (DMF=0.48 for HT29 versus DMF=0.73 for NIH 3T3). These results may confirm the views of the literature reports suggesting that use of vitamin E together with radiation could be favorable for colon cancer treatment; however, more experiments using more advanced techniques are needed

Two-Dimentional Photonic Crystal Waveguides

DEFF Research Database (Denmark)

Søndergaard, Thomas; Dridi, Kim

1999-01-01

possible a novel class of optical microcavities, whereas line defects make possible a novel class of waveguides. In this paper we will analyze two-dimensional photonic crystal waveguides based on photonic crystals with rods arranged on a triangular and a square lattice using a plane-wave expansion method......In the recent years a new class of periodic high-index contrast dielectric structures, known as photonic bandgap structures, has been discovered. In these structures frequency intervals, known as photonic bandgaps, where propagation of electromagnetic waves is not allowed, exist due to the periodic...... dielectric function. This is analogous to semiconductors, where electronic bandgaps exist due to the periodic arrangement of atoms. As is also the case for semiconductor structures, photonic bandgap structures may become of even greater value when defects are introduced. In particular, point defects make...

Advanced-Retarded Differential Equations in Quantum Photonic Systems

Science.gov (United States)

Alvarez-Rodriguez, Unai; Perez-Leija, Armando; Egusquiza, Iñigo L.; Gräfe, Markus; Sanz, Mikel; Lamata, Lucas; Szameit, Alexander; Solano, Enrique

2017-01-01

We propose the realization of photonic circuits whose dynamics is governed by advanced-retarded differential equations. Beyond their mathematical interest, these photonic configurations enable the implementation of quantum feedback and feedforward without requiring any intermediate measurement. We show how this protocol can be applied to implement interesting delay effects in the quantum regime, as well as in the classical limit. Our results elucidate the potential of the protocol as a promising route towards integrated quantum control systems on a chip. PMID:28230090

Time-dependent Bragg diffraction and short-pulse reflection by one-dimensional photonic crystals

International Nuclear Information System (INIS)

André, Jean-Michel; Jonnard, Philippe

2015-01-01

The time-dependence of the Bragg diffraction by one-dimensional photonic crystals and its influence on the short pulse reflection are studied in the framework of the coupled-wave theory. The indicial response of the photonic crystal is calculated and it appears that it presents a time-delay effect with a transient time conditioned by the extinction length. A numerical simulation is presented for a Bragg mirror in the x-ray domain and a pulse envelope modelled by a sine-squared shape. The potential consequences of the time-delay effect in time-dependent optics of short-pulses are emphasized. (paper)

Experimental investigation of photonic band gap in one-dimensional photonic crystals with metamaterials

International Nuclear Information System (INIS)

Chen, Yihang; Wang, Xinggang; Yong, Zehui; Zhang, Yunjuan; Chen, Zefeng; He, Lianxing; Lee, P.F.; Chan, Helen L.W.; Leung, Chi Wah; Wang, Yu

2012-01-01

Composite right/left-handed transmission lines with lumped element series capacitors and shunt inductors are used to experimentally realize the one-dimensional photonic crystals composed of single-negative metamaterials. The simulated and experimental results show that a special photonic band gap corresponding to zero-effective-phase (zero-φ eff ) may appear in the microwave regime. In contrast to the Bragg gap, by changing the length ratio of the two component materials, the width and depth of the zero-φ eff gap can be conveniently adjusted while keeping the center frequency constant. Furthermore, the zero-φ eff gap vanishes when both the phase-matching and impedance-matching conditions are satisfied simultaneously. These transmission line structures provide a good way for realizing microwave devices based on the zero-φ eff gap. -- Highlights: ► 1D photonic crystals with metamaterials were investigated experimentally. ► Both Bragg gap and zero-φ eff gap were observed in the microwave regime. ► The width and depth of the zero-φ eff gap were experimentally adjusted. ► Zero-φ eff gap was observed to be close when two match conditions were satisfied.

Experimental investigation of photonic band gap in one-dimensional photonic crystals with metamaterials

Energy Technology Data Exchange (ETDEWEB)

Chen, Yihang, E-mail: eon.chen@yahoo.com.cn [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); Wang, Xinggang [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); Yong, Zehui; Zhang, Yunjuan [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Chen, Zefeng [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou (China); He, Lianxing; Lee, P.F.; Chan, Helen L.W.; Leung, Chi Wah [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Wang, Yu, E-mail: apywang@inet.polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China)

2012-03-19

Composite right/left-handed transmission lines with lumped element series capacitors and shunt inductors are used to experimentally realize the one-dimensional photonic crystals composed of single-negative metamaterials. The simulated and experimental results show that a special photonic band gap corresponding to zero-effective-phase (zero-φ{sub eff}) may appear in the microwave regime. In contrast to the Bragg gap, by changing the length ratio of the two component materials, the width and depth of the zero-φ{sub eff} gap can be conveniently adjusted while keeping the center frequency constant. Furthermore, the zero-φ{sub eff} gap vanishes when both the phase-matching and impedance-matching conditions are satisfied simultaneously. These transmission line structures provide a good way for realizing microwave devices based on the zero-φ{sub eff} gap. -- Highlights: ► 1D photonic crystals with metamaterials were investigated experimentally. ► Both Bragg gap and zero-φ{sub eff} gap were observed in the microwave regime. ► The width and depth of the zero-φ{sub eff} gap were experimentally adjusted. ► Zero-φ{sub eff} gap was observed to be close when two match conditions were satisfied.

An FPGA-Integrated Time-to-Digital Converter Based on a Ring Oscillator for Programmable Delay Line Resolution Measurement

Directory of Open Access Journals (Sweden)

Chao Chen

2014-01-01

Full Text Available We describe the architecture of a time-to-digital converter (TDC, specially intended to measure the delay resolution of a programmable delay line (PDL. The configuration, which consists of a ring oscillator, a frequency divider (FD, and a period measurement circuit (PMC, is implemented in a field programmable gate array (FPGA device. The ring oscillator realized in loop containing a PDL and a look-up table (LUT generates periodic oscillatory pulses. The FD amplifies the oscillatory period from nanosecond range to microsecond range. The time-to-digital conversion is based on counting the number of clock cycles between two consecutive pulses of the FD by the PMC. Experiments have been conducted to verify the performance of the TDC. The achieved relative errors for four PDLs are within 0.50%–1.21% and the TDC has an equivalent resolution of about 0.4 ps.

Four-deep charge-time and pulse-width scaling discriminator for delay line MWPC's

International Nuclear Information System (INIS)

Lee, K.L.; Kirsten, F.A.; Grigorian, A.; Guiragossian, Z.G.T.

1976-01-01

A discriminator has been developed for digitizing both intercepted total charge and location of electromagnetic shower and particle trajectories in multi-wire proportional chambers read by delay lines. Determination of shower trajectory is aided by video signal integration followed by centroid-locating discrimination. Calibrated run-down of the signal integrating capacitor gives the charge information above a given threshold level. The discriminator is designed to handle up to four shower-induced video signals per event by incorporating steering circuits within the module. Each video signal is examined for time over an adjustable threshold. Video pulses with separation of less than 20 nsec are treated as a single pulse. Counter-logic circuits indicate the number of video signals digitized. These signal processing circuits provide a first level of data sifting which otherwise must be carried out with additional discriminator channels and added complexity in data recognition

Prehistory analysis using photon activation analysis

International Nuclear Information System (INIS)

Krausova, I.; Chvatil, D.; Tajer, J.

2017-01-01

Instrumental photon activation analysis (IPAA) is a suitable radio-analytical method for non-destructive determination of total nitrogen in various matrices. IPAA determination of nitrogen is based on 14 N (γ, n) 13 N nuclear reaction after high-energy photon irradiation. The analytically usable product of this photo-nuclear reaction is a positron emitter emitting only non-specific annihilation of 511 keV, which can be emitted by other radionuclides present in the sample. Some of them, besides the non-specific 511 keV line, also emit specific lines that allow their contribution to analytical radionuclide 13 N to be subtracted. An efficient source of high-energy photon radiation is the secondary bremsstrahlung generated by the conversion of the electron beam accelerated by a high-frequency circular accelerator - a microtron. The non-destructive IPAA contributed to the clarification of the origins of a precious bracelet originating from a fortified settlement in the area of Karlovy Vary - Drahovice from the late Bronze Age. (authors)

Enhanced Performance & Functionality of Tunable Delay Lines

Science.gov (United States)

2012-08-01

Based Tunable Optical Delays”, Optics Letters, Vol. 33, Issue 13, pp. 1518-1520 (2008). 2. Louis Christen, Irfan Fazal , Omer F. Yilmaz, Xiaoxia Wu...2008. 3. Omer F. Yilmaz, Louis Christen, Xiaoxia Wu, Scott R. Nuccio, Irfan Fazal , and Alan E. Willner, “Time-Slot-Interchange of 40 Gb/s Variable...F. Yilmaz, S. Khaleghi, L. Christen, I. Fazal , and A. E. Willner, “503 ns, Tunable Optical Delay of 40 Gb/s RZ-OOK using Additional λ-Conversion

Temporal compression of quantum-information-carrying photons using a photon-echo quantum memory approach

International Nuclear Information System (INIS)

Moiseev, S. A.; Tittel, W.

2010-01-01

We study quantum compression and decompression of light pulses that carry quantum information using a photon-echo quantum memory technique with controllable inhomogeneous broadening of an isolated atomic absorption line. We investigate media with differently broadened absorption profiles, transverse and longitudinal, finding that the recall efficiency can be as large as unity and that the quantum information encoded into the photonic qubits can remain unperturbed. Our results provide insight into reversible light-atom interaction and are interesting in view of future quantum communication networks, where pulse compression and decompression may play an important role in increasing the qubit rate or in mapping quantum information from photonic carriers with large optical bandwidth into atomic memories with smaller bandwidth.

Atomization efficiency and photon yield in laser-induced breakdown spectroscopy analysis of single nanoparticles in an optical trap

Science.gov (United States)

Purohit, Pablo; Fortes, Francisco J.; Laserna, J. Javier

2017-04-01

Laser-induced breakdown spectroscopy (LIBS) was employed for investigating the influence of particle size on the dissociation efficiency and the absolute production of photons per mass unit of airborne solid graphite spheres under single-particle regime. Particles of average diameter of 400 nm were probed and compared with 2 μm particles. Samples were first catapulted into aerosol form and then secluded in an optical trap set by a 532 nm laser. Trap stability was quantified before subjecting particles to LIBS analysis. Fine alignment of the different lines comprising the optical catapulting-optical trapping-laser-induced breakdown spectroscopy instrument and tuning of excitation parameters conditioning the LIBS signal such as fluence and acquisition delay are described in detail with the ultimate goal of acquiring clear spectroscopic data on masses as low as 75 fg. The atomization efficiency and the photon yield increase as the particle size becomes smaller. Time-resolved plasma imaging studies were conducted to elucidate the mechanisms leading to particle disintegration and excitation.

Tunable Optical True-Time Delay Devices Would Exploit EIT

Science.gov (United States)

Kulikov, Igor; DiDomenico, Leo; Lee, Hwang

2004-01-01

Tunable optical true-time delay devices that would exploit electromagnetically induced transparency (EIT) have been proposed. Relative to prior true-time delay devices (for example, devices based on ferroelectric and ferromagnetic materials) and electronically controlled phase shifters, the proposed devices would offer much greater bandwidths. In a typical envisioned application, an optical pulse would be modulated with an ultra-wideband radio-frequency (RF) signal that would convey the information that one seeks to communicate, and it would be required to couple differently delayed replicas of the RF signal to the radiating elements of a phased-array antenna. One or more of the proposed devices would be used to impose the delays and/or generate the delayed replicas of the RF-modulated optical pulse. The beam radiated or received by the antenna would be steered by use of a microprocessor-based control system that would adjust operational parameters of the devices to tune the delays to the required values. EIT is a nonlinear quantum optical interference effect that enables the propagation of light through an initially opaque medium. A suitable medium must have, among other properties, three quantum states (see Figure 1): an excited state (state 3), an upper ground state (state 2), and a lower ground state (state 1). These three states must form a closed system that exhibits no decays to other states in the presence of either or both of two laser beams: (1) a probe beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 1; and (2) a coupling beam having the wavelength corresponding to the photon energy equal to the energy difference between states 3 and 2. The probe beam is the one that is pulsed and modulated with an RF signal.

Saturated two-photon absorption by atoms in a perturber gas

International Nuclear Information System (INIS)

Nienhuis, G.

1980-01-01

We derive a general expression for the two-photon absorption spectrum of a three-state atom excited by two mono-chromatic radiation fields. Collisional line-broadening effects are incorporated, and the result allows inclusion of profiles with a validity outside the impact limit. Results of previous work are recovered in the appropriate limits. Saturation affects the different lines in the two-photon absorption spectrum in a different fashion. (orig.)

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

Fast pulse discriminator for photon counting at high photon densities

International Nuclear Information System (INIS)

Benoit, R.; Pedrini, A.

1977-03-01

A fast tunnel diode discriminator for photon counting up to 200MHz count frequency is described. The tunnel diode is operated on its apparent I.V. characteristics displayed when the diode is driven into its oscillating region. The pulse shaper-discriminator is completely D.C. coupled in order to avoid base-line shift at high pulse rates

Three-photon-excited luminescence from unsymmetrical cyanostilbene aggregates: morphology tuning and targeted bioimaging.

Science.gov (United States)

Mandal, Amal Kumar; Sreejith, Sivaramapanicker; He, Tingchao; Maji, Swarup Kumar; Wang, Xiao-Jun; Ong, Shi Li; Joseph, James; Sun, Handong; Zhao, Yanli

2015-05-26

We report an experimental observation of aggregation-induced enhanced luminescence upon three-photon excitation in aggregates formed from a class of unsymmetrical cyanostilbene derivatives. Changing side chains (-CH3, -C6H13, -C7H15O3, and folic acid) attached to the cyanostilbene core leads to instantaneous formation of aggregates with sizes ranging from micrometer to nanometer scale in aqueous conditions. The crystal structure of a derivative with a methyl side chain reveals the planarization in the unsymmetrical cyanostilbene core, causing luminescence from corresponding aggregates upon three-photon excitation. Furthermore, folic acid attached cyanostilbene forms well-dispersed spherical nanoaggregates that show a high three-photon cross-section of 6.0 × 10(-80) cm(6) s(2) photon(-2) and high luminescence quantum yield in water. In order to demonstrate the targeted bioimaging capability of the nanoaggregates, three cell lines (HEK293 healthy cell line, MCF7 cancerous cell line, and HeLa cancerous cell line) were employed for the investigations on the basis of their different folate receptor expression level. Two kinds of nanoaggregates with and without the folic acid targeting ligand were chosen for three-photon bioimaging studies. The cell viability of three types of cells incubated with high concentration of nanoaggregates still remained above 70% after 24 h. It was observed that the nanoaggregates without the folic acid unit could not undergo the endocytosis by both healthy and cancerous cell lines. No obvious endocytosis of folic acid attached nanoaggregates was observed from the HEK293 and MCF7 cell lines having a low expression of the folate receptor. Interestingly, a significant amount of endocytosis and internalization of folic acid attached nanoaggregates was observed from HeLa cells with a high expression of the folate receptor under three-photon excitation, indicating targeted bioimaging of folic acid attached nanoaggregates to the cancer cell line

Comment on ‘Time delays in molecular photoionization’

Science.gov (United States)

Baykusheva, Denitsa; Wörner, Hans Jakob

2017-04-01

In a recent article by Hockett et al (2016 J. Phys. B: At. Mol. Opt. Phys. 49 095602), time delays arising in the context of molecular single-photon ionization are investigated from a theoretical point of view. We argue that one of the central equations given in this article is incorrect and present a reformulation that is consistent with the established treatment of angle-dependent scattering delays (Eisenbud 1948 PhD Thesis Princeton University; Wigner 1955 Phys. Rev. 98 145-7 Smith 1960 Phys. Rev. 118 349-6 Nussenzveig 1972 Phys. Rev. D 6 1534-42).

Infrared photon-echo spectroscopy of water : The thermalization effects

NARCIS (Netherlands)

Pshenichnikov, Maxim S.; Yeremenko, Sergey; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

2005-01-01

The larger part of the nonlinear response in IR photon-echo and transient-grating spectroscopy on HDO-D2O mixtures at > 1-ps delays is found to originate from the D2O refractive index modulation due to local volume thermalization.

Delay 25 an ASIC for timing adjustment in LHC

NARCIS (Netherlands)

Furtado, H.; Schrader, J.H.R.; Marchioro, A.; Moreira, P.

A five channel programmable delay line ASIC was designed featuring 4 channels that allow to phase delay periodic or non-periodic digital signals and a master channel that can be used to phase delay a clock signal. The master channel serves as a calibration reference guaranteeing independence from

Optical transmission properties of an anisotropic defect cavity in one-dimensional photonic crystal

Science.gov (United States)

Ouchani, Noama; El Moussaouy, Abdelaziz; Aynaou, Hassan; El Hassouani, Youssef; El Boudouti, El Houssaine; Djafari-Rouhani, Bahram

2018-01-01

We investigate theoretically the possibility to control the optical transmission in the visible and infrared regions by a defective one dimensional photonic crystal formed by a combination of a finite isotropic superlattice and an anisotropic defect layer. The Green's function approach has been used to derive the reflection and the transmission coefficients, as well as the densities of states of the optical modes. We evaluate the delay times of the localized modes and we compare their behavior with the total densities of states. We show that the birefringence of an anisotropic defect layer has a significant impact on the behavior of the optical modes in the electromagnetic forbidden bands of the structure. The amplitudes of the defect modes in the transmission and the delay time spectrum, depend strongly on the position of the cavity layer within the photonic crystal. The anisotropic defect layer induces transmission zeros in one of the two components of the transmission as a consequence of a destructive interference of the two polarized waves within this layer, giving rise to negative delay times for some wavelengths in the visible and infrared light ranges. This property is a typical characteristic of the anisotropic photonic layer and is without analogue in their counterpart isotropic defect layers. This structure offers several possibilities for controlling the frequencies, transmitted intensities and the delay times of the optical modes in the visible and infrared regions. It can be a good candidate for realizing high-precision optical filters.

Invited Article: Electrically tunable silicon-based on-chip microdisk resonator for integrated microwave photonic applications

Directory of Open Access Journals (Sweden)

Weifeng Zhang

2016-11-01

Full Text Available Silicon photonics with advantages of small footprint, compatibility with the mature CMOS fabrication technology, and its potential for seamless integration with electronics is making a significant difference in realizing on-chip integration of photonic systems. A microdisk resonator (MDR with a strong capacity in trapping and storing photons is a versatile element in photonic integrated circuits. Thanks to the large index contrast, a silicon-based MDR with an ultra-compact footprint has a great potential for large-scale and high-density integrations. However, the existence of multiple whispering gallery modes (WGMs and resonance splitting in an MDR imposes inherent limitations on its widespread applications. In addition, the waveguide structure of an MDR is incompatible with that of a lateral PN junction, which leads to the deprivation of its electrical tunability. To circumvent these limitations, in this paper we propose a novel design of a silicon-based MDR by introducing a specifically designed slab waveguide to surround the disk and the lateral sides of the bus waveguide to suppress higher-order WGMs and to support the incorporation of a lateral PN junction for electrical tunability. An MDR based on the proposed design is fabricated and its optical performance is evaluated. The fabricated MDR exhibits single-mode operation with a free spectral range of 28.85 nm. Its electrical tunability is also demonstrated and an electro-optic frequency response with a 3-dB modulation bandwidth of ∼30.5 GHz is measured. The use of the fabricated MDR for the implementation of an electrically tunable optical delay-line and a tunable fractional-order temporal photonic differentiator is demonstrated.

Detection of nuclear material by photon activation inside cargo containers

Science.gov (United States)

Gmar, Mehdi; Berthoumieux, Eric; Boyer, Sébastien; Carrel, Frédérick; Doré, Diane; Giacri, Marie-Laure; Lainé, Frédéric; Poumarède, Bénédicte; Ridikas, Danas; Van Lauwe, Aymeric

2006-05-01

Photons with energies above 6 MeV can be used to detect small amounts of nuclear material inside large cargo containers. The method consists in using an intense beam of high-energy photons (bremsstrahlung radiation) in order to induce reactions of photofission on actinides. The measurement of delayed neutrons and delayed gammas emitted by fission products brings specific information on localization and quantification of the nuclear material. A simultaneous measurement of both of these delayed signals can overcome some important limitations due to matrix effects like heavy shielding and/or the presence of light elements as hydrogen. We have a long experience in the field of nuclear waste package characterization by photon interrogation and we have demonstrated that presently the detection limit can be less than one gram of actinide per ton of package. Recently we tried to extend our knowledge to assess the performance of this method for the detection of special nuclear materials in sea and air freights. This paper presents our first results based on experimental measurements carried out in the SAPHIR facility, which houses a linear electron accelerator with the energy range from 15 MeV to 30 MeV. Our experiments were also modeled using the full scale Monte Carlo techniques. In addition, and in a more general frame, due to the lack of consistent data on photonuclear reactions, we have been working on the development of a new photonuclear activation file (PAF), which includes cross sections for more than 600 isotopes including photofission fragment distributions and delayed neutron tables for actinides. Therefore, this work includes also some experimental results obtained at the ELSA electron accelerator, which is more adapted for precise basic nuclear data measurements.

Two-photon spin generation and detection

International Nuclear Information System (INIS)

Miah, M Idrish

2009-01-01

A time- and polarization-resolved two-photon pump-probe investigation is performed in lightly doped GaAs. We generate spin-polarized electrons in bulk GaAs at various temperatures using right-circularly polarized two-photon excitation and detect them by probing the spin-dependent transmission of the sample. The spin polarization (P) of conduction band electrons, as measured using probe pulses with the same (right) and opposite (left) circular polarization, is measured in dependences of pump-probe delay (Δt), lattice temperature (T L ), doping density (n) as well as of the excess photon energy ΔE 2ω = ℎ2ω - E g , where E g is the band gap energy. P is found to be decayed with Δt and enhanced with the decrease in T L or the increase in n. It is also found that P decreases with the increase in ΔE 2ω and depolarizes rapidly for ΔE 2ω > ΔE SO , where ΔE SO is the spin-orbit splitting energy. The results demonstrate that due to a much longer absorption depth highly polarized spins can be generated optically by two-photon pumping of bulk semiconductors.

Single Photon Sources in Silicon Carbide

International Nuclear Information System (INIS)

Brett Johnson

2014-01-01

Single photon sources in semiconductors are highly sought after as they constitute the building blocks of a diverse range of emerging technologies such as integrated quantum information processing, quantum metrology and quantum photonics. In this presentation, we show the first observation of single photon emission from deep level defects in silicon carbide (SiC). The single photon emission is photo-stable at room temperature and surprisingly bright. This represents an exciting alternative to diamond color centers since SiC possesses well-established growth and device engineering protocols. The defect is assigned to the carbon vacancy-antisite pair which gives rise to the AB photoluminescence lines. We discuss its photo-physical properties and their fabrication via electron irradiation. Preliminary measurements on 3C SiC nano-structures will also be discussed. (author)

Delayed decrease in hemispheric cerebral blood flow during Wada test demonstrated by 99mTc-HMPAO single photon emission computer tomography

International Nuclear Information System (INIS)

Ryding, E.; Sjoeholm, H.; Skeidsvoll, H.; Elmqvist, D.

1989-01-01

We describe how brain regions with a flow (and metabolism) decrease can be visualized after an injection of short-acting barbiturate in one of the internal carotid arteries during a Wada test. An intravenous administration of 99mTc-HMPAO was used to mark the relative flow distribution. The 99mTc-HMPAO distribution in the brain was recorded three-dimensionally about 1 h later, by means of a single photon emission computer tomograph. We show that the timing of the intravenous 99mTc-HMPAO administration during the Wada test is important for the visualization of the low-flow regions. The administration of the tracer substance should be delayed at least 30 s after the first signs of the barbiturate effect. The rCBF decrease in the barbiturate-injected cerebral hemisphere was associated with a simultaneous decrease in the contralateral, pharmacologically not directly affected, cerebellar hemisphere (crossed cerebellar diaschisis). (author)

Data analysis of photon beam position at PLS-II

Energy Technology Data Exchange (ETDEWEB)

Ko, J.; Shin, S., E-mail: tlssh@postech.ac.kr; Huang, Jung-Yun; Kim, D.; Kim, C.; Kim, Ilyou; Lee, T.-Y.; Park, C.-D.; Kim, K. R. [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-834 (Korea, Republic of); Cho, Moohyun [Department of Physics, POSTECH, Pohang, Kyungbuk 790-834 (Korea, Republic of)

2016-07-27

In the third generation light source, photon beam position stability is critical issue on user experiment. Generally photon beam position monitors have been developed for the detection of the real photon beam position and the position is controlled by feedback system in order to keep the reference photon beam position. In the PLS-II, photon beam position stability for front end of particular beam line, in which photon beam position monitor is installed, has been obtained less than rms 1μm for user service period. Nevertheless, detail analysis for photon beam position data in order to demonstrate the performance of photon beam position monitor is necessary, since it can be suffers from various unknown noises. (for instance, a back ground contamination due to upstream or downstream dipole radiation, undulator gap dependence, etc.) In this paper, we will describe the start to end study for photon beam position stability and the Singular Value Decomposition (SVD) analysis to demonstrate the reliability on photon beam position data.

In-core program for on line measurements of neutron, photon and nuclear heating parameters inside Jules Horowitz MTR reactor

International Nuclear Information System (INIS)

Lyoussi, A.; Reynard-Carette, C.

2014-01-01

Accurate on-line measurements of key parameters inside experimental channels of Material Testing Reactor are necessary to dimension the irradiation devices and consequently to conduct smart experiments on fuels and materials under suitable conditions. In particular the quantification of nuclear heating, a relevant parameter to reach adapted thermal conditions, has to be improved. These works focus on an important collaborative program between CEA and Aix-Marseille University called INCORE (Instrumentation for Nuclear radiations and Calorimetry On-line in Reactor) dedicated to the development of a new measurement methodology to quantify both nuclear heating and accurate radiation flux levels (neutrons and photons). The methodology, which is based on experiments carried out under irradiation conditions with a multi-sensor device (ionization chamber, fission chamber, gamma thermometer, calorimeter, SPND, SPGD) as well as works performed out-of nuclear/radiative environment on a reference sensor used to measure nuclear heating (calorimeter), is presented (authors)

Printed polymer photonic devices for optical interconnect systems

Science.gov (United States)

Subbaraman, Harish; Pan, Zeyu; Zhang, Cheng; Li, Qiaochu; Guo, L. J.; Chen, Ray T.

2016-03-01

Polymer photonic device fabrication usually relies on the utilization of clean-room processes, including photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which are expensive and are limited to areas as large as a wafer. Utilizing a novel and a scalable printing process involving ink-jet printing and imprinting, we have fabricated polymer based photonic interconnect components, such as electro-optic polymer based modulators and ring resonator switches, and thermo-optic polymer switch based delay networks and demonstrated their operation. Specifically, a modulator operating at 15MHz and a 2-bit delay network providing up to 35.4ps are presented. In this paper, we also discuss the manufacturing challenges that need to be overcome in order to make roll-to-roll manufacturing practically viable. We discuss a few manufacturing challenges, such as inspection and quality control, registration, and web control, that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. We have overcome these challenges, and currently utilizing our inhouse developed hardware and software tools, <10μm alignment accuracy at a 5m/min is demonstrated. Such a scalable roll-to-roll manufacturing scheme will enable the development of unique optoelectronic devices which can be used in a myriad of different applications, including communication, sensing, medicine, security, imaging, energy, lighting etc.

Parallel processing using an optical delay-based reservoir computer

Science.gov (United States)

Van der Sande, Guy; Nguimdo, Romain Modeste; Verschaffelt, Guy

2016-04-01

Delay systems subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By implementing a neuro-inspired computational scheme relying on the transient response to optical data injection, high processing speeds have been demonstrated. However, reservoir computing systems based on delay dynamics discussed in the literature are designed by coupling many different stand-alone components which lead to bulky, lack of long-term stability, non-monolithic systems. Here we numerically investigate the possibility of implementing reservoir computing schemes based on semiconductor ring lasers. Semiconductor ring lasers are semiconductor lasers where the laser cavity consists of a ring-shaped waveguide. SRLs are highly integrable and scalable, making them ideal candidates for key components in photonic integrated circuits. SRLs can generate light in two counterpropagating directions between which bistability has been demonstrated. We demonstrate that two independent machine learning tasks , even with different nature of inputs with different input data signals can be simultaneously computed using a single photonic nonlinear node relying on the parallelism offered by photonics. We illustrate the performance on simultaneous chaotic time series prediction and a classification of the Nonlinear Channel Equalization. We take advantage of different directional modes to process individual tasks. Each directional mode processes one individual task to mitigate possible crosstalk between the tasks. Our results indicate that prediction/classification with errors comparable to the state-of-the-art performance can be obtained even with noise despite the two tasks being computed simultaneously. We also find that a good performance is obtained for both tasks for a broad range of the parameters. The results are discussed in detail in [Nguimdo et al., IEEE Trans. Neural Netw. Learn. Syst. 26, pp. 3301-3307, 2015

Analytical determination of the bifurcation thresholds in stochastic differential equations with delayed feedback.

Science.gov (United States)

Gaudreault, Mathieu; Drolet, François; Viñals, Jorge

2010-11-01

Analytical expressions for pitchfork and Hopf bifurcation thresholds are given for a nonlinear stochastic differential delay equation with feedback. Our results assume that the delay time τ is small compared to other characteristic time scales, not a significant limitation close to the bifurcation line. A pitchfork bifurcation line is found, the location of which depends on the conditional average , where x(t) is the dynamical variable. This conditional probability incorporates the combined effect of fluctuation correlations and delayed feedback. We also find a Hopf bifurcation line which is obtained by a multiple scale expansion around the oscillatory solution near threshold. We solve the Fokker-Planck equation associated with the slowly varying amplitudes and use it to determine the threshold location. In both cases, the predicted bifurcation lines are in excellent agreement with a direct numerical integration of the governing equations. Contrary to the known case involving no delayed feedback, we show that the stochastic bifurcation lines are shifted relative to the deterministic limit and hence that the interaction between fluctuation correlations and delay affect the stability of the solutions of the model equation studied.

Delay generation methods with reduced memory requirements

DEFF Research Database (Denmark)

Tomov, Borislav Gueorguiev; Jensen, Jørgen Arendt

2003-01-01

Modern diagnostic ultrasound beamformers require delay information for each sample along the image lines. In order to avoid storing large amounts of focusing data, delay generation techniques have to be used. In connection with developing a compact beamformer architecture, recursive algorithms were......) For the best parametric approach, the gate count was 2095, the maximum operation speed was 131.9 MHz, the power consumption at 40 MHz was 10.6 mW, and it requires 4 12-bit words for each image line and channel. 2) For the piecewise-linear approximation, the corresponding numbers are 1125 gates, 184.9 MHz, 7...

Mitochondrial respiratory complex I probed by delayed luminescence spectroscopy

Science.gov (United States)

Baran, Irina; Ionescu, Diana; Privitera, Simona; Scordino, Agata; Mocanu, Maria Magdalena; Musumeci, Francesco; Grasso, Rosaria; Gulino, Marisa; Iftime, Adrian; Tofolean, Ioana Teodora; Garaiman, Alexandru; Goicea, Alexandru; Irimia, Ruxandra; Dimancea, Alexandru; Ganea, Constanta

2013-12-01

The role of mitochondrial complex I in ultraweak photon-induced delayed photon emission [delayed luminescence (DL)] of human leukemia Jurkat T cells was probed by using complex I targeting agents like rotenone, menadione, and quercetin. Rotenone, a complex I-specific inhibitor, dose-dependently increased the mitochondrial level of reduced nicotinamide adenine dinucleotide (NADH), decreased clonogenic survival, and induced apoptosis. A strong correlation was found between the mitochondrial levels of NADH and oxidized flavin mononucleotide (FMNox) in rotenone-, menadione- and quercetin-treated cells. Rotenone enhanced DL dose-dependently, whereas quercetin and menadione inhibited DL as well as NADH or FMNox. Collectively, the data suggest that DL of Jurkat cells originates mainly from mitochondrial complex I, which functions predominantly as a dimer and less frequently as a tetramer. In individual monomers, both pairs of pyridine nucleotide (NADH/reduced nicotinamide adenine dinucleotide phosphate) sites and flavin (FMN-a/FMN-b) sites appear to bind cooperatively their specific ligands. Enhancement of delayed red-light emission by rotenone suggests that the mean time for one-electron reduction of ubiquinone or FMN-a by the terminal Fe/S center (N2) is 20 or 284 μs, respectively. All these findings suggest that DL spectroscopy could be used as a reliable, sensitive, and robust technique to probe electron flow within complex I in situ.

Optical buffer based on monolithic InP phased-array 1×16 switch with silica-PLC pitch converter and ultra-compact coiled fiber delay lines

NARCIS (Netherlands)

Tanemura, T.; Soganci, I. M.; Oyama, T.; Ohyama, T.; Mino, S.; Williams, K. A.; Calabretta, N.; Dorren, H. J S; Nakano, Y.

2010-01-01

We demonstrate large-capacity high-resolution optical buffer, comprising 1×16 InP switch and ultra-compact delay lines based on thin-cladding highly nonlinear fibers. Silica-PLC-based pitch converter is employed to realize uniform coupling from all 16 switch ports simultaneously.

Magnetohydrodynamic waves, electrohydrodynamic waves and photons

International Nuclear Information System (INIS)

Carstoin, J.

1984-01-01

Two new subjects have lately attracted increased attention: the magnetohydrodynamics (m.h.d.) and the theory of lasers. Equally important is the subject of electrohydrodynamics (e.h.d.). Now, clearly, all electromagnetic waves carry photons; it is the merit of Louis de Broglie to have had reconciled the validity of the Maxwell equations with existence of the latter. I have, recently, derived L. de Broglie's equations from the equations C. It seems natural to assume that the m.h.d. waves carry also photons, but how to reconcile the m.h.d axioms with the existence of photons ... a problem which has, so far, escaped the notice of physicists. In the lines which follows, an attempt is made to incorporate the photons in the m.h.d. waves, re e.h.d. waves in a rather simple fashion

Electronics system for transuranic waste assays using a photon interrogation technique

International Nuclear Information System (INIS)

Johnson, L.O.; Lawrence, R.S.

1979-12-01

This report documents the development of electronics for a neutron detection system used in experiments to demonstrate the feasibility of a photon interrogation technique for transuranic (TRU) waste assays. The system consists of the neutron detection and signal conditioning circuits, variable time-gate generators, and a data acquisition system. The data acquisition system is configured using commercially available scalers, timers, teletype, and control components. The remainder of the system, with the exception of the neutron detectors, uses components designed in-house. The neutron detection system consists of 3 He proportional counters installed in a polyethylene moderator assembly. The counters are direct-coupled to a high-count-rate, current-sensitive preamplifier. The preamplifier and an additional two-stage amplifier are also installed in the moderator assembly. Signal conditioning includes baseline restoration and fast discrimination. A variable time-gate generator with logic gates allows for separation of prompt and delayed neutron counts, and generation of prompt and delayed deadtimes. The 3 He proportional counters will detect not only the neutrons from the TRU waste sample, but also the high-energy photons used to induce fission in the sample. The burst of photons (gamma flash) tends to overload and paralyze the electronics. This system has been designed to recover from a worst-case gamma flash overload within 10 microseconds. The system has met all the requirements generated for the photon interrogation experiments

Pulse Compression of Phase-matched High Harmonic Pulses from a Time-Delay Compensated Monochromator

Directory of Open Access Journals (Sweden)

Ito Motohiko

2013-03-01

Full Text Available Pulse compression of single 32.6-eV high harmonic pulses from a time-delay compensated monochromator was demonstrated down to 11±3 fs by compensating the pulse front tilt. The photon flux was intensified up to 5.7×109 photons/s on target by implementing high harmonic generation under a phase matching condition in a hollow fiber used for increasing the interaction length.

Signal integrity analysis on discontinuous microstrip line

International Nuclear Information System (INIS)

Qiao, Qingyang; Dai, Yawen; Chen, Zipeng

2013-01-01

In high speed PCB design, microstirp lines were used to control the impedance, however, the discontinuous microstrip line can cause signal integrity problems. In this paper, we use the transmission line theory to study the characteristics of microstrip lines. Research results indicate that the discontinuity such as truncation, gap and size change result in the problems such as radiation, reflection, delay and ground bounce. We change the discontinuities to distributed parameter circuits, analysed the steady-state response and transient response and the phase delay. The transient response cause radiation and voltage jump.

Modeling of gain saturation effects in active semiconductor photonic crystal waveguides

DEFF Research Database (Denmark)

Chen, Yaohui; Mørk, Jesper

2012-01-01

In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated.......In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated....

In vitro evaluation of photon and raster-scanned carbon ion radiotherapy in combination with gemcitabine in pancreatic cancer cell lines

International Nuclear Information System (INIS)

Shafie, Rami A. El; Habermehl, Daniel; Rieken, Stefan

2013-01-01

Pancreatic cancer is the fourth leading cause of cancer deaths, being responsible for 6% of all cancer-related deaths. Conventional radiotherapy with or without additional chemotherapy has been applied in the past in the context of neoadjuvant or adjuvant therapy concepts with only modest results, however new radiation modalities, such as particle therapy with promising physical and biological characteristics, present an alternative treatment option for patients with pancreatic cancer. Up until now the raster scanning technique employed at our institution for the application of carbon ions has been unique, and no radiobiological data using pancreatic cancer cells has been available yet. The aim of this study was to evaluate cytotoxic effects that can be achieved by treating pancreatic cancer cell lines with combinations of X-rays and gemcitabine, or alternatively with carbon ion irradiation and gemcitabine, respectively. Human pancreatic cancer cell lines AsPC-1, BxPC-3 and Panc-1 were irradiated with photons and carbon ions at various doses and treated with gemcitabine. Photon irradiation was applied with a biological cabin X-ray irradiator, and carbon ion irradiation was applied with an extended Bragg peak (linear energy transfer (LET) 103 keV/μm) using the raster scanning technique at the Heidelberg Ion Therapy Center (HIT). Responsiveness of pancreatic cancer cells to the treatment was measured by clonogenic survival. Clonogenic survival curves were then compared to predicted curves that were calculated employing the local effect model (LEM). Cell survival curves were calculated from the surviving fractions of each combination experiment and compared to a drug control that was only irradiated with X-rays or carbon ions, without application of gemcitabine. In terms of cytotoxicity, additive effects were achieved for the cell lines Panc-1 and BxPC-3, and a slight radiosensitizing effect was observed for AsPC-1. Relative biological effectiveness (RBE) of carbon

Delayed Luminescence and Biophotons from Biological Materials

Science.gov (United States)

Knoesel, Ernst; Hann, Patrick; Garzon, Maria; Pfeiffer, Erik; Lofland, Samuel

2008-03-01

There has recently been increased interest in the field of biophotonics, since it is a non-invasive technique. Many biological systems, such as yeast, bacteria, leaves, seeds, and algae display the unusual phenomenon of a weak, delayed luminescence on the timescale of seconds to minutes after transient illumination. It is also observed that the time decay of the biophotonic emission is not exponential, even after the delay, and that there can be oscillations in intensity with time, which depend on the duration of the illumination. Results from two types of yeast, i.e. bread yeast, and saccharomyces, as well as those from several types of algae are presented. Possible mechanisms for the source of the ultraweak photon emission are discussed.

Small sensitivity to temperature variations of Si-photonic Mach-Zehnder interferometer using Si and SiN waveguides

Science.gov (United States)

Hiraki, Tatsurou; Fukuda, Hiroshi; Yamada, Koji; Yamamoto, Tsuyoshi

2015-03-01

We demonstrated a small sensitivity to temperature variations of delay-line Mach-Zehnder interferometer (DL MZI) on a Si photonics platform. The key technique is to balance a thermo-optic effect in the two arms by using waveguide made of different materials. With silicon and silicon nitride waveguides, the fabricated DL MZI with a free-spectrum range of ~40 GHz showed a wavelength shift of -2.8 pm/K with temperature variations, which is 24 times smaller than that of the conventional Si-waveguide DL MZI. We also demonstrated the decoding of the 40-Gbit/s differential phase-shift keying signals to on-off keying signals with various temperatures. The tolerable temperature variation for the acceptable power penalty was significantly improved due to the small wavelength shifts.

Room-Temperature Single-Photon Emission from Micrometer-Long Air-Suspended Carbon Nanotubes

Science.gov (United States)

Ishii, A.; Uda, T.; Kato, Y. K.

2017-11-01

Statistics of photons emitted by mobile excitons in individual carbon nanotubes are investigated. Photoluminescence spectroscopy is used to identify the chiralities and suspended lengths of air-suspended nanotubes, and photon-correlation measurements are performed at room temperature on telecommunication-wavelength nanotube emission with a Hanbury-Brown-Twiss setup. We obtain zero-delay second-order correlation g(2 )(0 ) less than 0.5, indicating single-photon generation. Excitation power dependence of the photon antibunching characteristics is examined for nanotubes with various chiralities and suspended lengths, where we find that the minimum value of g(2 )(0 ) is obtained at the lowest power. The influence of exciton diffusion and end quenching is studied by Monte Carlo simulations, and we derive an analytical expression for the minimum value of g(2 )(0 ). Our results indicate that mobile excitons in micrometer-long nanotubes can in principle produce high-purity single photons, leading to new design strategies for quantum photon sources.

Photon-photon colliders

International Nuclear Information System (INIS)

Sessler, A.M.

1995-04-01

Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

Two-photon spin generation and detection

Energy Technology Data Exchange (ETDEWEB)

Miah, M Idrish, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)

2009-02-21

A time- and polarization-resolved two-photon pump-probe investigation is performed in lightly doped GaAs. We generate spin-polarized electrons in bulk GaAs at various temperatures using right-circularly polarized two-photon excitation and detect them by probing the spin-dependent transmission of the sample. The spin polarization (P) of conduction band electrons, as measured using probe pulses with the same (right) and opposite (left) circular polarization, is measured in dependences of pump-probe delay ({Delta}t), lattice temperature (T{sub L}), doping density (n) as well as of the excess photon energy {Delta}E{sub 2{omega}}= {h_bar}2{omega} - E{sub g}, where E{sub g} is the band gap energy. P is found to be decayed with {Delta}t and enhanced with the decrease in T{sub L} or the increase in n. It is also found that P decreases with the increase in {Delta}E{sub 2{omega}}and depolarizes rapidly for {Delta}E{sub 2{omega}}> {Delta}E{sub SO}, where {Delta}E{sub SO} is the spin-orbit splitting energy. The results demonstrate that due to a much longer absorption depth highly polarized spins can be generated optically by two-photon pumping of bulk semiconductors.

Photonic Beamformer Model Based on Analog Fiber-Optic Links’ Components

International Nuclear Information System (INIS)

Volkov, V A; Gordeev, D A; Ivanov, S I; Lavrov, A P; Saenko, I I

2016-01-01

The model of photonic beamformer for wideband microwave phased array antenna is investigated. The main features of the photonic beamformer model based on true-time-delay technique, DWDM technology and fiber chromatic dispersion are briefly analyzed. The performance characteristics of the key components of photonic beamformer for phased array antenna in the receive mode are examined. The beamformer model composed of the components available on the market of fiber-optic analog communication links is designed and tentatively investigated. Experimental demonstration of the designed model beamforming features includes actual measurement of 5-element microwave linear array antenna far-field patterns in 6-16 GHz frequency range for antenna pattern steering up to 40°. The results of experimental testing show good accordance with the calculation estimates. (paper)

Seed Nutrition and Quality, Seed Coat Boron and Lignin Are Influenced by Delayed Harvest in Exotically-Derived Soybean Breeding Lines under High Heat.

Science.gov (United States)

Bellaloui, Nacer; Smith, James R; Mengistu, Alemu

2017-01-01

The timing of harvest is a major factor affecting seed quality in soybean, particularly in Midsouthern USA, when rain during harvest period is not uncommon. The objective of this research was to evaluate the effects of time of harvest on soybean seed quality (seed composition, germination, seed coat boron, and lignin) in high germinability (HG) breeding lines (50% exotic) developed under high heat. The hypothesis was that seeds of HG lines possess physiological and genetic traits for a better seed quality at harvest maturity and delayed harvest. A 2-year field experiment was conducted under irrigated conditions. Results showed that, at harvest maturity, the exotic HG lines had higher seed protein, oleic acid, sugars, seed coat boron, and seed coat lignin, but lower seed oil compared with the non-exotic checks (Control), confirming our hypothesis. At 28 days after harvest maturity (delayed harvest), the content of seed protein, oleic acid, sugars, seed coat boron, and seed coat lignin were higher in some of the HG lines compared with the checks, indicating a possible involvement of these seed constituents, especially seed coat boron and seed coat lignin, in maintaining seed coat integrity and protecting seed coat against physical damage. Highly significant positive correlations were found between germination and seed protein, oleic acid, sugars, and seed coat boron and seed coat lignin. Highly significant negative correlation was found between germination and oil, linoleic acid, seed coat wrinkling, shattering, and hard seed. Yields of some HG lines were competitive with checks. This research demonstrated that time of harvesting is an important factor influencing seed protein and oil production. Also, since high oleic acid is desirable for oxidative stability, shelf-life and biodiesel properties, using HG lines could positively influence these important traits. This result should suggest to breeders of some of the advantages of selecting for high seed coat boron and

Photonic integrated circuits unveil crisis-induced intermittency.

Science.gov (United States)

Karsaklian Dal Bosco, Andreas; Akizawa, Yasuhiro; Kanno, Kazutaka; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki

2016-09-19

We experimentally investigate an intermittent route to chaos in a photonic integrated circuit consisting of a semiconductor laser with time-delayed optical feedback from a short external cavity. The transition from a period-doubling dynamics to a fully-developed chaos reveals a stage intermittently exhibiting these two dynamics. We unveil the bifurcation mechanism underlying this route to chaos by using the Lang-Kobayashi model and demonstrate that the process is based on a phenomenon of attractor expansion initiated by a particular distribution of the local Lyapunov exponents. We emphasize on the crucial importance of the distribution of the steady-state solutions introduced by the time-delayed feedback on the existence of this intermittent dynamics.

Heralded wave packet manipulation and storage of a frequency-converted pair photon at telecom wavelength

Science.gov (United States)

Kroh, Tim; Ahlrichs, Andreas; Sprenger, Benjamin; Benson, Oliver

2017-09-01

Future quantum networks require a hybrid platform of dissimilar quantum systems. Within the platform, joint quantum states have to be mediated either by single photons, photon pairs or entangled photon pairs. The photon wavelength has to lie within the telecommunication band to enable long-distance fibre transmission. In addition, the temporal shape of the photons needs to be tailored to efficiently match the involved quantum systems. Altogether, this requires the efficient coherent wavelength-conversion of arbitrarily shaped single-photon wave packets. Here, we demonstrate the heralded temporal filtering of single photons as well as the synchronisation of state manipulation and detection as key elements in a typical experiment, besides of delaying a photon in a long fibre. All three are realised by utilising commercial telecommunication fibre-optical components which will permit the transition of quantum networks from the lab to real-world applications. The combination of these renders a temporally filtering single-photon storage in a fast switchable fibre loop possible.

Optical Properties and Wave Propagation in Semiconductor-Based Two-Dimensional Photonic Crystals

International Nuclear Information System (INIS)

Mario Agio

2002-01-01

This work is a theoretical investigation on the physical properties of semiconductor-based two-dimensional photonic crystals, in particular for what concerns systems embedded in planar dielectric waveguides (GaAs/AlGaAs, GaInAsP/InP heterostructures, and self-standing membranes) or based on macro-porous silicon. The photonic-band structure of photonic crystals and photonic-crystal slabs is numerically computed and the associated light-line problem is discussed, which points to the issue of intrinsic out-of-lane diffraction losses for the photonic bands lying above the light line. The photonic states are then classified by the group theory formalism: each mode is related to an irreducible representation of the corresponding small point group. The optical properties are investigated by means of the scattering matrix method, which numerically implements a variable-angle-reflectance experiment; comparison with experiments is also provided. The analysis of surface reflectance proves the existence of selection rules for coupling an external wave to a certain photonic mode. Such rules can be directly derived from symmetry considerations. Lastly, the control of wave propagation in weak-index contrast photonic-crystal slabs is tackled in view of designing building blocks for photonic integrated circuits. The proposed designs are found to comply with the major requirements of low-loss propagation, high and single-mode transmission. These notions are then collected to model a photonic-crystal combiner for an integrated multi-wavelength-source laser

Optical Properties and Wave Propagation in Semiconductor-Based Two-Dimensional Photonic Crystals

Energy Technology Data Exchange (ETDEWEB)

Agio, Mario [Iowa State Univ., Ames, IA (United States)

2002-12-31

This work is a theoretical investigation on the physical properties of semiconductor-based two-dimensional photonic crystals, in particular for what concerns systems embedded in planar dielectric waveguides (GaAs/AlGaAs, GaInAsP/InP heterostructures, and self-standing membranes) or based on macro-porous silicon. The photonic-band structure of photonic crystals and photonic-crystal slabs is numerically computed and the associated light-line problem is discussed, which points to the issue of intrinsic out-of-lane diffraction losses for the photonic bands lying above the light line. The photonic states are then classified by the group theory formalism: each mode is related to an irreducible representation of the corresponding small point group. The optical properties are investigated by means of the scattering matrix method, which numerically implements a variable-angle-reflectance experiment; comparison with experiments is also provided. The analysis of surface reflectance proves the existence of selection rules for coupling an external wave to a certain photonic mode. Such rules can be directly derived from symmetry considerations. Lastly, the control of wave propagation in weak-index contrast photonic-crystal slabs is tackled in view of designing building blocks for photonic integrated circuits. The proposed designs are found to comply with the major requirements of low-loss propagation, high and single-mode transmission. These notions are then collected to model a photonic-crystal combiner for an integrated multi-wavelength-source laser.

Photon Factory activity report, 1991

International Nuclear Information System (INIS)

1992-01-01

The Photon Factory is a national synchrotron radiation research facility affiliated with the National Laboratory for High Energy Physics located in Tsukuba Science City. The Photon Factory consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV electron/positron storage ring, beam lines and experimental stations. All the facilities for synchrotron radiation research are open to scientists. A part of the accumulation ring of the TRISTAN main ring has been used as a synchrotron radiation source in the energy range from 5.8 to 6.5 GeV. The Photon Factory is composed of three divisions of Injector Linac, Light Source and Instrumentation. The researches of each divisions are reviewed, and the users' short reports are collected. The list of published papers with author index is also included in the publication. (K.I.) 233 refs

Comparison of the effects of photon versus carbon ion irradiation when combined with chemotherapy in vitro

International Nuclear Information System (INIS)

Schlaich, Fabian; Brons, Stephan; Haberer, Thomas; Debus, Jürgen; Combs, Stephanie E; Weber, Klaus-Josef

2013-01-01

Characterization of combination effects of chemotherapy drugs with carbon ions in comparison to photons in vitro. The human colon adenocarcinoma cell line WiDr was tested for combinations with camptothecin, cisplatin, gemcitabine and paclitaxel. In addition three other human tumour cell lines (A549: lung, LN-229: glioblastoma, PANC-1: pancreas) were tested for the combination with camptothecin. Cells were irradiated with photon doses of 2, 4, 6 and 8 Gy or carbon ion doses of 0.5, 1, 2 and 3 Gy. Cell survival was assessed using the clonogenic growth assay. Treatment dependent changes in cell cycle distribution (up to 12 hours post-treatment) were measured by FACS analysis after propidium-iodide staining. Apoptosis was monitored for up to 36 hours post-treatment by Nicoletti-assay (with qualitative verification using DAPI staining). All cell lines exhibited the well-known increase of killing efficacy per unit dose of carbon ion exposure, with relative biological efficiencies at 10% survival (RBE 10 ) ranging from 2.3 to 3.7 for the different cell lines. In combination with chemotherapy additive toxicity was the prevailing effect. Only in combination with gemcitabine or cisplatin (WiDr) or camptothecin (all cell lines) the photon sensitivity was slightly enhanced, whereas purely independent toxicities were found with the carbon ion irradiation, in all cases. Radiation-induced cell cycle changes displayed the generally observed dose-dependent G2-arrest with little effect on S-phase fraction for all cell lines for photons and for carbon ions. Only paclitaxel showed a significant induction of apoptosis in WiDr cell line but independent of the used radiation quality. Combined effects of different chemotherapeutics with photons or with carbon ions do neither display qualitative nor substantial quantitative differences. Small radiosensitizing effects, when observed with photons are decreased with carbon ions. The data support the idea that a radiochemotherapy with common

Thermo-optically induced interactions in photon Bose-Einstein Condensates

Science.gov (United States)

Alaeian, Hadiseh; Bartels, Clara; Weitz, Martin

Bose-Einstein condensation (BEC), a new state of matter, emerges when the de Broglie wavelength of bosons becomes larger than the particle separation, leading to a macroscopic occupation of the system ground state. Followed by the first experimental demonstrations of BEC in cold atomic gases, this phase transition has been observed in other bosonic gases, as polaritons and phonons. The most recent one, photon BEC, is a promising candidate for a new generation of coherent photon sources. Due to their infancy, however, many of their properties are still unknown or only partly explored. In this talk I will present my latest results on the implications of photon interactions in photon BECs. In particular, I will investigate the effect of a thermo-optic non-linearity, leading to spatially non-local and delayed interactions. Starting from the steady state behavior, I will explore the spectrum of elementary excitations as a small perturbation. Moreover, I will discuss the resulting effective photon dispersion, manifesting various properties including possible superfluidity, as well as roton and maxon modes. The implications of physical parameters as absorption, number of photons in the condensate, and cavity trap on the dispersion will be discussed. The results of this study shed new light on the implication of interactions in photonic many-body systems. Hadiseh Alaeian acknowledges the generous support from Alexander von Humboldt Foundation.

Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

Theory of the effect of third-harmonic generation on three-photon resonantly enhanced multiphoton ionization in focused beams

International Nuclear Information System (INIS)

Payne, M.G.; Garrett, W.R.

1983-01-01

Multiphoton ionization in the region near a three-photon resonance is treated for focused, plane-polarized Gaussian beams with diffraction-limited beam divergence. In this situation, a third-harmonic field is generated within the laser beam. At, and very near, three-photon resonance the driving rate for the upper-state probability amplitude due to one-photon absorption of third-harmonic light becomes nearly equal to the corresponding three-photon rate due to the laser field, but these effects are 180 0 out of phase. As a consequence of this cancellation between two pumping terms, the three-photon resonance line essentially disappears at moderate concentrations and the observed ionization has a line shape that is close to the phase-matching curve for third-harmonic generation. The ionization signal, near but not on the resonance, is due almost entirely to absorption of third-harmonic photons plus other laser photons; three-photon resonantly enhanced multiphoton ionization by the laser is much weaker. This is particularly true on the blue side of the three-photon resonance at detunings where phase matching occurs. The problem is treated quite generally with predictions of the full line shape for n-photon ionization and third-harmonic light generation near three-photon resonance, including the rather strong influences of positively dispersive buffer gases. We also show that the cancellation between the one-photon and the three-photon process is partially spoiled in the presence of a counterpropagating beam at the same frequency

Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems.

Science.gov (United States)

Bai, Lihui; Harder, M; Chen, Y P; Fan, X; Xiao, J Q; Hu, C-M

2015-06-05

We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.

A hemispherical photoelectron spectrometer with 2-dimensional delay-line detector and integrated spin-polarization analysis

International Nuclear Information System (INIS)

Plucinski, L.; Oelsner, A.; Matthes, F.; Schneider, C.M.

2010-01-01

Photoelectron spectrometers usually allow detection of either spin-resolved energy-distribution curves (EDCs) at single emission angle, or 2D angle-vs.-energy images without spin-resolution. We have combined the two detection schemes into one spectrometer system which permits simultaneous detection of a 1D spin-resolved EDC and a 2D angular map. A state-of-the-art hemispherical analyzer is used as an energy filter. Its original scintillator detector has been replaced by a delay-line-detector (DLD), and part of the electron beam is allowed to pass through to reach the spin-polarized low energy electron diffraction (SPLEED) spin-detector mounted subsequently. The electron-optics between DLD and SPLEED contains a 90 o deflector to feature simultaneous detection of in-plane and out-of-plane spin components. These electron-optics have been optimized for high transmission to reduce acquisition times in the spin-resolved mode.

Introduction to Focus Issue: Time-delay dynamics

Science.gov (United States)

Erneux, Thomas; Javaloyes, Julien; Wolfrum, Matthias; Yanchuk, Serhiy

2017-11-01

The field of dynamical systems with time delay is an active research area that connects practically all scientific disciplines including mathematics, physics, engineering, biology, neuroscience, physiology, economics, and many others. This Focus Issue brings together contributions from both experimental and theoretical groups and emphasizes a large variety of applications. In particular, lasers and optoelectronic oscillators subject to time-delayed feedbacks have been explored by several authors for their specific dynamical output, but also because they are ideal test-beds for experimental studies of delay induced phenomena. Topics include the control of cavity solitons, as light spots in spatially extended systems, new devices for chaos communication or random number generation, higher order locking phenomena between delay and laser oscillation period, and systematic bifurcation studies of mode-locked laser systems. Moreover, two original theoretical approaches are explored for the so-called Low Frequency Fluctuations, a particular chaotical regime in laser output which has attracted a lot of interest for more than 30 years. Current hot problems such as the synchronization properties of networks of delay-coupled units, novel stabilization techniques, and the large delay limit of a delay differential equation are also addressed in this special issue. In addition, analytical and numerical tools for bifurcation problems with or without noise and two reviews on concrete questions are proposed. The first review deals with the rich dynamics of simple delay climate models for El Nino Southern Oscillations, and the second review concentrates on neuromorphic photonic circuits where optical elements are used to emulate spiking neurons. Finally, two interesting biological problems are considered in this Focus Issue, namely, multi-strain epidemic models and the interaction of glucose and insulin for more effective treatment.

On the impact of fiber-delay-lines (FDL) in an all-optical network (AON) bottleneck without wavelength conversion

Science.gov (United States)

Argibay-Losada, Pablo Jesus; Sahin, Gokhan

2014-08-01

Random access memories (RAM) are fundamental in conventional electronic switches and routers to manage short-term congestion and to decrease data loss probabilities. Switches in all-optical networks (AONs), however, do not have access to optical RAM, and therefore are prone to much higher loss levels than their electronic counterparts. Fiber-delay-lines (FDLs), able to delay an optical data packet a fixed amount of time, have been proposed in the literature as a means to alleviate those high loss levels. However, they are extremely bulky to manage, so their usage introduces a trade-off between practicality and performance in the design and operation of the AON. In this paper we study the influence that FDLs have in the performance of flows crossing an all-optical switch that acts as their bottleneck. We show how extremely low numbers of FDLs (e.g., 1 or 2) can help in reducing losses by several orders of magnitude in several illustrative scenarios with high aggregation levels. Our results therefore suggest that FDLs can be a practical means of dealing with congestion in AONs in the absence of optical RAM buffers or of suitable data interchange protocols specifically designed for AONs.

Sub-megahertz linewidth single photon source

Directory of Open Access Journals (Sweden)

Markus Rambach

2016-12-01

Full Text Available We report 100% duty cycle generation of sub-MHz single photon pairs at the rubidium D1 line using cavity-enhanced spontaneous parametric downconversion. The temporal intensity cross correlation function exhibits a bandwidth of 666±16 kHz for the single photons, an order of magnitude below the natural linewidth of the target transition. A half-wave plate inside our cavity helps to achieve triple resonance between pump, signal, and idler photon, reducing the bandwidth and simplifying the locking scheme. Additionally, stabilisation of the cavity to the pump frequency enables the 100% duty cycle. The quantum nature of the source is confirmed by the idler-triggered second-order autocorrelation function at τ=0 to be gs,s(2(0= 0.016±0.002 for a heralding rate of 5 kHz. The generated photons are well-suited for storage in quantum memory schemes with sub-natural linewidths, such as gradient echo memories.

A 2D Rods-in-Air Square-Lattice Photonic Crystal Optical Switch

Science.gov (United States)

2009-03-01

4] Tao Chu, Hirohito Yamada, Satomi Ishida, Yasuhiko Arakawa, Thermooptic switch based on photonic-crystal line-defect waveguides, IEEE Photon...Ishida, Yasuhiko Arakawa, Hiroyuki Fujita, Hiroshi Toshiyoshi, Design and fabrication on MEMS optical mod- ulators integrated with Phc waveguide, in

Single-photon blockade in a hybrid cavity-optomechanical system via third-order nonlinearity

Science.gov (United States)

Sarma, Bijita; Sarma, Amarendra K.

2018-04-01

Photon statistics in a weakly driven optomechanical cavity, with Kerr-type nonlinearity, are analyzed both analytically and numerically. The single-photon blockade effect is demonstrated via calculations of the zero-time-delay second-order correlation function g (2)(0). The analytical results obtained by solving the Schrödinger equation are in complete conformity with the results obtained through numerical solution of the quantum master equation. A systematic study on the parameter regime for observing photon blockade in the weak coupling regime is reported. The parameter regime where the photon blockade is not realizable due to the combined effect of nonlinearities owing to the optomechanical coupling and the Kerr-effect is demonstrated. The experimental feasibility with state-of-the-art device parameters is discussed and it is observed that photon blockade could be generated at the telecommunication wavelength. An elaborate analysis of the thermal effects on photon antibunching is presented. The system is found to be robust against pure dephasing-induced decoherences and thermal phonon number fluctuations.

Preparing technicians for photonics industries and organizations

Science.gov (United States)

Souders, John; Hull, Dan

2012-10-01

U.S. photonics organizations need about 800 new photonics technicians each year. Thirty-one community and technical colleges have approximately 700 students enrolled in photonics related programs; about 275 of them complete their coursework and enter the workforce each year. A disparity exists between the demand and supply of qualified photonics technicians in the U.S. OP-TEC, the National Center for Optics and Photonics Education is a consortium of seven colleges, under the leadership of the University of Central Florida, and sponsored by NSF. OP-TEC's mission is to increase the quantity and quality of photonics technicians prepared at two-year colleges. OP-TEC maintains the National Photonics Skill Standards for Technicians, provides curriculum models, teaching materials, faculty training/professional development and planning services to strengthen existing college photonics programs and to attract and support new ones. OP-TEC is converting its text materials to E-Books to support students in technical programs. Through OP-TEC's recruitment efforts 84 additional colleges are interested in initiating new photonics programs. The OP-TEC Photonics College Network (OPCN) consists of 28 colleges that are currently providing photonics education. This fall OPCN will lead an additional national effort to further educate employed photonics technicians through on-line courses, complemented by lab experiences at nearby colleges. OP-TEC is expanding its outreach to photonics employers and colleges by regionalizing its approach to offering its services. OP-TEC is also planning to develop new curricula and instructional materials for AAS programs to prepare Precision Optics Technicians. This paper will detail OP-TEC's work with particular emphases on its materials and services.

Corpuscular event-by-event simulation of quantum optics experiments: application to a quantum-controlled delayed-choice experiment

International Nuclear Information System (INIS)

De Raedt, Hans; Delina, M; Jin, Fengping; Michielsen, Kristel

2012-01-01

A corpuscular simulation model of optical phenomena that does not require knowledge of the solution of a wave equation of the whole system and reproduces the results of Maxwell's theory by generating detection events one by one is discussed. The event-based corpuscular model gives a unified description of multiple-beam fringes of a plane parallel plate and a single-photon Mach-Zehnder interferometer, Wheeler's delayed choice, photon tunneling, quantum eraser, two-beam interference, Einstein-Podolsky-Rosen-Bohm and Hanbury Brown-Twiss experiments. The approach is illustrated by applying it to a recent proposal for a quantum-controlled delayed choice experiment, demonstrating that also this thought experiment can be understood in terms of particle processes only.

A Quantized Analog Delay for an ir-UWB Quadrature Downconversion Autocorrelation Receiver

NARCIS (Netherlands)

Bagga, S.; Zhang, L.; Serdijn, W.A.; Long, J.R.; Busking, E.B.

2005-01-01

A quantized analog delay is designed as a requirement for the autocorrelation function in the quadrature downconversion autocorrelation receiver (QDAR). The quantized analog delay is comprised of a quantizer, multiple binary delay lines and an adder circuit. Being the foremost element, the quantizer

Inclusive hard processes in photon-photon and photon-proton interactions

OpenAIRE

Glasman, Claudia

1999-01-01

Measurements of jet, prompt photon, high-pT hadron and heavy quark production in photon-induced processes provide tests of QCD and are sensitive to the photon parton densities. A review of the latest experimental results in photon-photon and photon-proton interactions is presented. Next-to-leading-order QCD calculations for these measurements are discussed.

arXiv Squeezed relic photons beyond the horizon

CERN Document Server

Giovannini, Massimo

2017-11-14

Owing to the analogy with the ordinary photons in the visible range of the electromagnetic spectrum, the Glauber theory is generalized to address the quantum coherence of the gauge field fluctuations parametrically amplified during an inflationary stage of expansion. The first and second degrees of quantum coherence of relic photons are then computed beyond the effective horizon defined by the evolution of the susceptibility. In the zero-delay limit the Hanbury Brown-Twiss correlations exhibit a super-Poissonian statistics which is however different from the conventional results of the single-mode approximation customarily employed, in quantum optics, to classify the coherence properties of visible light. While in the case of large-scale curvature perturbations the degrees of quantum coherence coincide with the naive expectation of the single-mode approximation, the net degree of second-order coherence computed for the relic photons diminishes thanks to the effect of the polarizations. We suggest that the Han...

Frequency-multiplexed bias and readout of a 16-pixel superconducting nanowire single-photon detector array

Science.gov (United States)

Doerner, S.; Kuzmin, A.; Wuensch, S.; Charaev, I.; Boes, F.; Zwick, T.; Siegel, M.

2017-07-01

We demonstrate a 16-pixel array of microwave-current driven superconducting nanowire single-photon detectors with an integrated and scalable frequency-division multiplexing architecture, which reduces the required number of bias and readout lines to a single microwave feed line. The electrical behavior of the photon-sensitive nanowires, embedded in a resonant circuit, as well as the optical performance and timing jitter of the single detectors is discussed. Besides the single pixel measurements, we also demonstrate the operation of a 16-pixel array with a temporal, spatial, and photon-number resolution.

Photon-photon interactions

International Nuclear Information System (INIS)

Gilman, F.J.

1980-01-01

A brief summary of the present status of photon-photon interactions is presented. Stress is placed on the use of two-photon collisions to test present ideas on the quark constituents of hadrons and on the theory of strong interactions

Spontaneous and light-induced photon emission from intact brains of chick embryos

Institute of Scientific and Technical Information of China (English)

张锦珠; 于文斗; 孙彤

1997-01-01

Photon emission (PE) and light-induced photon emission(LPE) of intact brains isolated from chick embryos have been measured by using the single photon counting device. Experimental results showed that the intensi-ty level of photon emission was detected to be higher from intact brain than from the medium in which the brain was immerged during measuring, and the emission intensity was related to the developmental stages, the healthy situation of the measured embryos, and the freshness of isolated brains as well. After white light illumination, a short-life de-layed emission from intact brains was observed, and its relaxation behavior followed a hyperbolic rather than an expo-nential law. According to the hypothesis of biophoton emission originating from a delocalized coherent electromagnetic field and Frohlich’s idea of coherent long-range interactions in biological systems, discussions were made on the signifi-cance of photon emission in studying cell communication, biological regulation, living system’

Efficient non-linear two-photon effects from the Cesium 6D manifold

Science.gov (United States)

Haluska, Nathan D.; Perram, Glen P.; Rice, Christopher A.

2018-02-01

We report several non-linear process that occur when two-photon pumping the cesium 6D states. Cesium vapor possess some of the largest two-photon pump cross sections in nature. Pumping these cross sections leads to strong amplified spontaneous emission that we observe on over 17 lasing lines. These new fields are strong enough to couple with the pump to create additional tunable lines. We use a heat pipe with cesium densities of 1014 to 1016 cm-3 and 0 to 5 Torr of helium buffer gas. The cesium 6D States are interrogated by both high energy pulses and low power CW sources. We observe four-wave mixing, six-wave mixing, potential two-photon lasing, other unknown nonlinear processes, and the persistence of some processes at low thresholds. This system is also uniquely qualified to support two-photon lasing under the proper conditions.

Study and development of a method allowing the identification of actinides inside nuclear waste packages, by active neutron or photon interrogation and delayed gamma-ray spectrometry

International Nuclear Information System (INIS)

Carrel, F.

2007-10-01

An accurate estimation of the alpha-activity of a nuclear waste package is necessary to select the best mode of storage. The main purpose of this work is to develop a non-destructive active method, based on the fission process and allowing the identification of actinides ( 235 U, 238 U, 239 Pu). These three elements are the main alpha emitters contained inside a package. Our technique is based on the detection of delayed gammas emitted by fission products. These latter are created by irradiation with the help of a neutron or photon beam. Performances of this method have been investigated after an Active Photon or Neutron Interrogation (INA or IPA). Three main objectives were fixed in the framework of this thesis. First, we measured many yields of photofission products to compensate the lack of data in the literature. Then, we studied experimental performances of this method to identify a given actinide ( 239 Pu in fission, 235 U in photofission) present in an irradiated mixture. Finally, we assessed the application of this technique on different mock-up packages for both types of interrogation (118 l mock-up package containing EVA in fission, 220 l mock-up package with a wall of concrete in photofission). (author)

Nuclear size and cell division delay

International Nuclear Information System (INIS)

Bird, R.P.

1986-01-01

Radiation-induced division delay has been linked to damage at the nuclear envelope. Further, cells in G 2 phase are drastically arrested by high LET radiation such that single particles traversing cell nuclei may produce measurable division delay. A modest effort was initiated using two related cell lines of different size, near-diploid cells and near-tetraploid cells of Chinese hamster origin, to compare their sensitivity for radiation-induced division delay. If the nuclear surface is the critical target, then a larger nuclear cross-section presented to an alpha-particle beam should exhibit delay induced by a lesser particle fluence. Preliminary estimates of the extent of delay in asynchronous cultures following low doses of gamma-irradiation or of alpha-irradiation were made by in-situ observation of the time of onset of mitosis and by fixation and staining of cultures to determine the mitotic index as a function of time after irradiation. The basic approach to evaluating division delay will be to use Colecemid to accumulate mitotic cells over a period of time

Delay Estimator and Improved Proportionate Multi-Delay Adaptive Filtering Algorithm

Directory of Open Access Journals (Sweden)

E. Verteletskaya

2012-04-01

Full Text Available This paper pertains to speech and acoustic signal processing, and particularly to a determination of echo path delay and operation of echo cancellers. To cancel long echoes, the number of weights in a conventional adaptive filter must be large. The length of the adaptive filter will directly affect both the degree of accuracy and the convergence speed of the adaptation process. We present a new adaptive structure which is capable to deal with multiple dispersive echo paths. An adaptive filter according to the present invention includes means for storing an impulse response in a memory, the impulse response being indicative of the characteristics of a transmission line. It also includes a delay estimator for detecting ranges of samples within the impulse response having relatively large distribution of echo energy. These ranges of samples are being indicative of echoes on the transmission line. An adaptive filter has a plurality of weighted taps, each of the weighted taps having an associated tap weight value. A tap allocation/control circuit establishes the tap weight values in response to said detecting means so that only taps within the regions of relatively large distributions of echo energy are turned on. Thus, the convergence speed and the degree of estimation in the adaptation process can be improved.

Testing Delays Resulting in Increased Identification Accuracy in Line-Ups and Show-Ups.

Science.gov (United States)

Dekle, Dawn J.

1997-01-01

Investigated time delays (immediate, two-three days, one week) between viewing a staged theft and attempting an eyewitness identification. Compared lineups to one-person showups in a laboratory analogue involving 412 subjects. Results show that across all time delays, participants maintained a higher identification accuracy with the showup…

Quantum secure direct communication network with superdense coding and decoy photons

International Nuclear Information System (INIS)

Deng Fuguo; Li Xihan; Li Chunyan; Zhou Ping; Zhou Hongyu

2007-01-01

A quantum secure direct communication network scheme is proposed with quantum superdense coding and decoy photons. The servers on a passive optical network prepare and measure the quantum signal, i.e. a sequence of the d-dimensional Bell states. After confirming the security of the photons received from the receiver, the sender codes his secret message on them directly. For preventing a dishonest server from eavesdropping, some decoy photons prepared by measuring one photon in the Bell states are used to replace some original photons. One of the users on the network can communicate to any other one. This scheme has the advantage of high capacity, and it is more convenient than others as only a sequence of photons is transmitted in quantum line

Photon Mass Limits from Fast Radio Bursts

CERN Document Server

Bonetti, Luca; Mavromatos, Nikolaos E.; Sakharov, Alexander S.; Sarkisyan-Grinbaum, Edward K.G.; Spallicci, Alessandro D.A.M.

2016-06-10

The frequency-dependent time delays in fast radio bursts (FRBs) can be used to constrain the photon mass, if the FRB redshifts are known, but the similarity between the frequency dependences of dispersion due to plasma effects and a photon mass complicates the derivation of a limit on $m_\\gamma$. The redshift of FRB 150418 has been measured to $\\sim 2$% and its dispersion measure (DM) is known to $\\sim 0.1$%, but the strength of the constraint on $m_\\gamma$ is limited by uncertainties in the modelling of the host galaxy and the Milky Way, as well as possible inhomogeneities in the intergalactic medium (IGM). Allowing for these uncertainties, the recent data on FRB 150418 indicate that $m_\\gamma \\lesssim 1.7 \\times 10^{-14}$ eV c$^{-2}$ ($4.6 \\times 10^{-50}$ kg). In the future, the different redshift dependences of the plasma and photon mass contributions to DM can be used to improve the sensitivity to $m_\\gamma$ if more FRB redshifts are measured. For a fixed fractional uncertainty in the extra-galactic cont...

Application of the Monte Carlo method in calculation of energy-time distribution from a pulsed photon source in homogeneous air environment

International Nuclear Information System (INIS)

Ilic, R.D.; Vojvodic, V.I.; Orlic, M.P.

1981-01-01

The stochastic nature of photon interactions with matter and the characteristics of photon transport through real materials, are very well suited for applications of the Monte Carlo method in calculations of the energy-space distribution of photons. Starting from general principles of the Monte Carlo method, physical-mathematical model of photon transport from a pulsed source is given for the homogeneous air environment. Based on that model, a computer program is written which is applied in calculations of scattered photons delay spectra and changes of the photon energy spectrum. Obtained results provide the estimation of the timespace function of the electromagnetic field generated by photon from a pulsed source. (author)

Photoemission and photoionization time delays and rates

Science.gov (United States)

Gallmann, L.; Jordan, I.; Wörner, H. J.; Castiglioni, L.; Hengsberger, M.; Osterwalder, J.; Arrell, C. A.; Chergui, M.; Liberatore, E.; Rothlisberger, U.; Keller, U.

2017-01-01

Ionization and, in particular, ionization through the interaction with light play an important role in fundamental processes in physics, chemistry, and biology. In recent years, we have seen tremendous advances in our ability to measure the dynamics of photo-induced ionization in various systems in the gas, liquid, or solid phase. In this review, we will define the parameters used for quantifying these dynamics. We give a brief overview of some of the most important ionization processes and how to resolve the associated time delays and rates. With regard to time delays, we ask the question: how long does it take to remove an electron from an atom, molecule, or solid? With regard to rates, we ask the question: how many electrons are emitted in a given unit of time? We present state-of-the-art results on ionization and photoemission time delays and rates. Our review starts with the simplest physical systems: the attosecond dynamics of single-photon and tunnel ionization of atoms in the gas phase. We then extend the discussion to molecular gases and ionization of liquid targets. Finally, we present the measurements of ionization delays in femto- and attosecond photoemission from the solid–vacuum interface. PMID:29308414

Photoemission and photoionization time delays and rates

Directory of Open Access Journals (Sweden)

L. Gallmann

2017-11-01

Full Text Available Ionization and, in particular, ionization through the interaction with light play an important role in fundamental processes in physics, chemistry, and biology. In recent years, we have seen tremendous advances in our ability to measure the dynamics of photo-induced ionization in various systems in the gas, liquid, or solid phase. In this review, we will define the parameters used for quantifying these dynamics. We give a brief overview of some of the most important ionization processes and how to resolve the associated time delays and rates. With regard to time delays, we ask the question: how long does it take to remove an electron from an atom, molecule, or solid? With regard to rates, we ask the question: how many electrons are emitted in a given unit of time? We present state-of-the-art results on ionization and photoemission time delays and rates. Our review starts with the simplest physical systems: the attosecond dynamics of single-photon and tunnel ionization of atoms in the gas phase. We then extend the discussion to molecular gases and ionization of liquid targets. Finally, we present the measurements of ionization delays in femto- and attosecond photoemission from the solid–vacuum interface.

Experimental and numerical study of electrical crosstalk in photonic integrated circuits

NARCIS (Netherlands)

Yao, W.; Gilardi, G.; Calabretta, N.; Smit, M.K.; Wale, M.J.

2015-01-01

This paper presents measurement results on electrical crosstalk between interconnect lines and electro-optical phaseshifters in photonic integrated circuits. The results indicate that overall crosstalk originates from radiative and substrate coupling between lines and from shared ground connections.

Gastric emptying measurements: delayed and complex emptying patterns without appropriate correction

Energy Technology Data Exchange (ETDEWEB)

Moore, J.G.; Christian, P.E.; Taylor, A.T.; Alazraki, N.

1985-10-01

Anteriorly acquired and geometric mean corrected gastric emptying curves of solids and liquid isotopic-labeled meals were compared in 37 subjects given 61 meals of three different sizes. Anterior data alone consistently and significantly underestimated solid-phase gastric emptying rates with all meal sizes when compared to geometric mean acquired data. However, with liquids there were only slight differences between anterior and anterior and posterior geometric mean corrected emptying-rates. The difference probably reflects greater attenuation of the 140 kev photon of /sup 99m/Tc compared to the 247 keV photon of In. With anterior data alone, an apparent early delay in emptying of solids was present with all meal sizes and the resultant emptying curves were nonlinear in shape. Geometric mean correction resulted in the linearization of the solid-phase emptying curves and essentially eliminated the apparent delay in emptying or lag phase noted with the anterior data alone. Based on our results, geometric mean correction techniques are necessary for accurate assessment of radioisotopic-labeled solid meals.

CONFERENCE: Photon-photon collisions

International Nuclear Information System (INIS)

Anon.

1983-01-01

Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists

Ogura-CMS in Chinese cabbage (Brassica rapa ssp. pekinensis) causes delayed expression of many nuclear genes.

Science.gov (United States)

Dong, Xiangshu; Kim, Wan Kyu; Lim, Yong-Pyo; Kim, Yeon-Ki; Hur, Yoonkang

2013-02-01

We investigated the mechanism regulating cytoplasmic male sterility (CMS) in Brassica rapa ssp. pekinensis using floral bud transcriptome analyses of Ogura-CMS Chinese cabbage and its maintainer line in B. rapa 300-K oligomeric probe (Br300K) microarrays. Ogura-CMS Chinese cabbage produced few and infertile pollen grains on indehiscent anthers. Compared to the maintainer line, CMS plants had shorter filaments and plant growth, and delayed flowering and pollen development. In microarray analysis, 4646 genes showed different expression, depending on floral bud size, between Ogura-CMS and its maintainer line. We found 108 and 62 genes specifically expressed in Ogura-CMS and its maintainer line, respectively. Ogura-CMS line-specific genes included stress-related, redox-related, and B. rapa novel genes. In the maintainer line, genes related to pollen coat and germination were specifically expressed in floral buds longer than 3mm, suggesting insufficient expression of these genes in Ogura-CMS is directly related to dysfunctional pollen. In addition, many nuclear genes associated with auxin response, ATP synthesis, pollen development and stress response had delayed expression in Ogura-CMS plants compared to the maintainer line, which is consistent with the delay in growth and development of Ogura-CMS plants. Delayed expression may reduce pollen grain production and/or cause sterility, implying that mitochondrial, retrograde signaling delays nuclear gene expression. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Flux qubit to a transmission line

Energy Technology Data Exchange (ETDEWEB)

Haeberlein, Max; Baust, Alexander; Zhong, Ling; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Anderson, Gustav; Wang, Lujun; Eder, Peter; Fischer, Michael; Goetz, Jan; Xie, Edwar; Schwarz, Manuel; Wulschner, Karl Friedrich; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Menzel, Edwin [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)

2015-07-01

Within the last decade, superconducting qubits coupled to microwave resonators have been extensively studied within the framework of quantum electrodynamics. Ultimately, quantum computing seems within reach in such architectures. However, error correction schemes are necessary to achieve the required fidelity in multi-qubit operations, drastically increasing the number of qubits involved. In this work, we couple a flux qubit to a transmission line where it interacts with itinerant microwave photons granting access to all-optical quantum computing. In this approach, travelling photons generate entanglement between two waveguides, containing the qubit information. In this presentation, we show experimental data on flux qubits coupled to transmission lines. Furthermore, we will discuss entanglement generation between two separate paths.

Pulsed single-photon spectrometer by frequency-to-time mapping using chirped fiber Bragg gratings.

Science.gov (United States)

Davis, Alex O C; Saulnier, Paul M; Karpiński, Michał; Smith, Brian J

2017-05-29

A fiber-integrated spectrometer for single-photon pulses outside the telecommunications wavelength range based upon frequency-to-time mapping, implemented by chromatic group delay dispersion (GDD), and precise temporally-resolved single-photon counting, is presented. A chirped fiber Bragg grating provides low-loss GDD, mapping the frequency distribution of an input pulse onto the temporal envelope of the output pulse. Time-resolved detection with fast single-photon-counting modules enables monitoring of a wavelength range from 825 nm to 835 nm with nearly uniform efficiency at 55 pm resolution (24 GHz at 830 nm). To demonstrate the versatility of this technique, spectral interference of heralded single photons and the joint spectral intensity distribution of a photon-pair source are measured. This approach to single-photon-level spectral measurements provides a route to realize applications of time-frequency quantum optics at visible and near-infrared wavelengths, where multiple spectral channels must be simultaneously monitored.

On the origin of gamma rays in Fermi blazars: beyond the broad line region.

Science.gov (United States)

Costamante, L.; Cutini, S.; Tosti, G.; Antolini, E.; Tramacere, A.

2018-05-01

The gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the Broad Line Region (BLR), the so-called BLR External Compton scenario. We test this scenario on the Fermi gamma-ray spectra of 106 broad-line blazars detected with the highest significance or largest BLR, by looking for cut-off signatures at high energies compatible with γ-γ interactions with BLR photons. We do not find evidence for the expected BLR absorption. For 2/3 of the sources, we can exclude any significant absorption (τmax 5). We conclude that for 9 out of 10 objects, the jet does not interact with BLR photons. Gamma-rays seem either produced outside the BLR most of the time, or the BLR is ˜100 × larger than given by reverberation mapping. This means that i) External Compton on BLR photons is disfavoured as the main gamma-ray mechanism, vs IC on IR photons from the torus or synchrotron self-Compton; ii) the Fermi gamma-ray spectrum is mostly intrinsic, determined by the interaction of the particle distribution with the seed-photons spectrum; iii) without suppression by the BLR, broad-line blazars can become copious emitters above 100 GeV, as demonstrated by 3C 454.3. We expect the CTA sky to be much richer of broad-line blazars than previously thought.

On-ground detection of an electron-positron annihilation line from thunderclouds.

Science.gov (United States)

Umemoto, D; Tsuchiya, H; Enoto, T; Yamada, S; Yuasa, T; Kawaharada, M; Kitaguchi, T; Nakazawa, K; Kokubun, M; Kato, H; Okano, M; Tamagawa, T; Makishima, K

2016-02-01

Thunderclouds can produce bremsstrahlung gamma-ray emission, and sometimes even positrons. At 00:27:00 (UT) on 13 January 2012, an intense burst of gamma rays from a thundercloud was detected by the GROWTH experiment, located in Japan, facing the Sea of Japan. The event started with a sharp gamma-ray flash with a duration of gamma-ray emission lasting for ∼60 s. The spectrum of this prolonged emission reached ∼10 MeV, and contained a distinct line emission at 508±3(stat.)±5(sys.) keV, to be identified with an electron-positron annihilation line. The line was narrow within the instrumental energy resolution (∼80keV), and contained 520±50 photons which amounted to ∼10% of the total signal photons of 5340±190 detected over 0.1-10 MeV. As a result, the line equivalent width reached 280±40 keV, which implies a nontrivial result. The result suggests that a downward positron beam produced both the continuum and the line photons.

Two-Color Single-Photon Photoinitiation and Photoinhibition for Subdiffraction Photolithography

Science.gov (United States)

Scott, Timothy F.; Kowalski, Benjamin A.; Sullivan, Amy C.; Bowman, Christopher N.; McLeod, Robert R.

2009-05-01

Controlling and reducing the developed region initiated by photoexposure is one of the fundamental goals of optical lithography. Here, we demonstrate a two-color irradiation scheme whereby initiating species are generated by single-photon absorption at one wavelength while inhibiting species are generated by single-photon absorption at a second, independent wavelength. Co-irradiation at the second wavelength thus reduces the polymerization rate, delaying gelation of the material and facilitating enhanced spatial control over the polymerization. Appropriate overlapping of the two beams produces structures with both feature sizes and monomer conversions otherwise unobtainable with use of single- or two-photon absorption photopolymerization. Additionally, the generated inhibiting species rapidly recombine when irradiation with the second wavelength ceases, allowing for fast sequential exposures not limited by memory effects in the material and thus enabling fabrication of complex two- or three-dimensional structures.

Raman scattering in condensed media placed in photon traps

Science.gov (United States)

Goncharov, A. P.; Gorelik, V. S.; Krawtsow, A. V.

2007-11-01

A new type of resonator cells (photon traps) has been worked out, which ensures the Raman opalescence regime (i.e., the conditions under which the relative Raman scattering intensity at the outlet of the cells increases significantly as compared to the exciting line intensity. The Raman scattering spectra of a number of organic and inorganic compounds placed in photon traps are studied under pulse-periodic excitation by a copper-vapor laser.

Coupled quantum electrodynamics in photonic crystal cavities towards controlled phase gate operations

International Nuclear Information System (INIS)

Xiao, Y-F; Gao, J; McMillan, J F; Yang, X; Wong, C W; Zou, X-B; Chen, Y-L; Han, Z-F; Guo, G-C

2008-01-01

In this paper, a scalable photonic crystal cavity array, in which single embedded quantum dots (QDs) are coherently interacting, is studied theoretically. Firstly, we examine the spectral character and optical delay brought about by the coupled cavities interacting with single QDs, in an optical analogue to electromagnetically induced transparency. Secondly, we then examine the usability of this coupled QD-cavity system for quantum phase gate operation and our numerical examples suggest that a two-qubit system with fidelity above 0.99 and photon loss below 0.04 is possible.

Structural Color Patterns by Electrohydrodynamic Jet Printed Photonic Crystals.

Science.gov (United States)

Ding, Haibo; Zhu, Cun; Tian, Lei; Liu, Cihui; Fu, Guangbin; Shang, Luoran; Gu, Zhongze

2017-04-05

In this work, we demonstrate the fabrication of photonic crystal patterns with controllable morphologies and structural colors utilizing electrohydrodynamic jet (E-jet) printing with colloidal crystal inks. The final shape of photonic crystal units is controlled by the applied voltage signal and wettability of the substrate. Optical properties of the structural color patterns are tuned by the self-assembly of the silica nanoparticle building blocks. Using this direct printing technique, it is feasible to print customized functional patterns composed of photonic crystal dots or photonic crystal lines according to relevant printing mode and predesigned tracks. This is the first report for E-jet printing with colloidal crystal inks. Our results exhibit promising applications in displays, biosensors, and other functional devices.

The strong will of the photon

International Nuclear Information System (INIS)

Schuler, Gerhard

1993-01-01

Among today's elementary particles, the photon, the massless carrier of the electromagnetic force, plays a special role. At high energy, it has a dual character - sometimes pointlike and structureless, elsewhere with a hadronic structure. This is reminiscent of the duality of radiation and matter established at the beginning of the century. But while this wave-particle duality is understood in quantum mechanics, we have no complete description of high energy hadronic interactions. Quantum chromodynamics, the field theory of quarks and gluons, comes nearest, but calculations are not always possible. Physicists have to resort to intuitive pictures and models to supplement formal theory. The hadronic Side of the photon is a rich field, both theoretically and experimentally, studied using a range of reactions at all the major front-line accelerators and storage rings, culminating most recently with first data from the new HERA electron proton collider at DESY, Hamburg. The photon was first regarded as structureless. The first hint of photon structure was probably electronpositron pair creation by photons in an electromagnetic field. In relativistic quantum field theory, a particle contains not only its 'bare' state, but also contributions from all states coupled to it by the interaction. Thus in quantum terms the photon also contains electron-positron pairs, which can materialize in high-energy reactions

Temporal and spatial spectroscopy of the plasma formation in crossed electric and magnetic fields

International Nuclear Information System (INIS)

Miljevic, V.I.; Tosic, D.D.

1980-01-01

The formation of argon plasma in crossed electric and magnetic fields in a cylindrical diode with an incandescent cathode has been studied by means of the delay time of the anode current pulse and photon pulse (corresponding to the optical transitions) and the shape of the voltage collapse. The working conditions were: pressure p=10 -5 --10 -3 Torr, anode voltage U/sub a/=800 V, and maximum magnetic field B/sub max/=1200 Gs. Photoelectrical recording of spectral lines was performed with a monochromator in the wavelength range 3600--6000 A, and the total optical spectrum was recorded simultaneously on a photoplate in a separate spectrograph in the wavelength range 2000--10 000 A. The delay time of the anode current pulse and photon pulse are approximately the same and are in the millisecond range. The delay time of the photon pulse does not depend on the wavelength. Simultaneously the spectral lines of the working gas (A II), residual gas (O II), and tungsten (W I) appear. Tungsten atoms appear at the moment of breakdown as a result of ion bombardment of the cathode. Neutral atomic lines of the working gas (A I) have not been observed. Radial analysis shows that the delay time of the photon pulse does not depend on the radius. Spectroscopic results have been analyzed in terms of excitation and ionization processes during the formation time. The shape of the voltage collapse suggests the streamer breakdown mechanism

Printed low velocity delay lines for cathode readout of proportional chambers

International Nuclear Information System (INIS)

Bosshard, R.; Chase, R.L.; Fischer, J.; Radeka, V.

1974-01-01

A readout which simultaneously insures a correct electric field, a satisfactory induced signal, the delay function itself, and low particle scattering is described for multiwire proportional chambers. (U.S.)

Iodine-131 imaging using 284 keV photons with a small animal CZT-SPECT system dedicated to low-medium-energy photon detection.

Science.gov (United States)

Kojima, Akihiro; Gotoh, Kumiko; Shimamoto, Masako; Hasegawa, Koki; Okada, Seiji

2016-02-01

Iodine-131 is widely used for radionuclide therapy because of its β-particle and for diagnostic imaging employing its principal gamma ray. Since that principal gamma ray has the relatively high energy of 364 keV, small animal single-photon emission computed tomography (SPECT) imaging systems may be required to possess the ability to image such higher energy photons. The aim of this study was to investigate the possibility of imaging I-131 using its 284 keV photons instead of its 364 keV photons in a small animal SPECT imaging system dedicated to the detection of low-medium-energy photons (below 300 keV). The imaging system used was a commercially available preclinical SPECT instrument with CZT detectors that was equipped with multi-pinhole collimators and was accompanied by a CT imager. An energy window for I-131 imaging was set to a photopeak of 284 keV with a low abundance compared with 364 keV photons. Small line sources and two mice, one of each of two types, that were injected with NaI-131 were scanned. Although higher counts occurred at the peripheral region of the reconstructed images due to the collimator penetration by the 364 keV photons, the shape of the small line sources could be well visualized. The measured spatial resolution was relatively poor (~1.9 mm for full width at half maximum and ~3.9 mm for full width at tenth maximum). However, a good linear correlation between SPECT values and the level of I-131 radioactivity was observed. Furthermore, the uptake of NaI-131 to the thyroid gland for the two mice was clearly identified in the 3D-SPECT image fused with the X-ray CT image. We conclude that the use of an energy window set on the photopeak of 284 keV and the multi-pinhole collimator may permit I-131 imaging for a preclinical CZT-SPECT system that does not have the ability to acquire images using the 364 keV photons.

CMS Higgs Search in 2011 and 2012 data: candidate photon-photon event (8 TeV)

CERN Multimedia

McCauley, Thomas

2013-01-01

Event recorded with the CMS detector in 2012 at a proton-proton centre of mass energy of 8 TeV. The event shows characteristics expected from the decay of the SM Higgs boson to a pair of photons (dashed yellow lines and green towers). The event could also be due to known standard model background processes.

Experimental verification of photon: A program for use in x-ray shielding calculations

International Nuclear Information System (INIS)

Brauer, E.; Thomlinson, W.

1987-01-01

At the National Synchrotron Light Source, a computer program named PHOTON has been developed to calculate radiation dose values around a beam line. The output from the program must be an accurate guide to beam line shielding. To test the program, a series of measurements of radiation dose were carried out using existing beam lines; the results were compared to the theoretical calculations of PHOTON. Several different scattering geometries, scattering materials, and sets of walls and shielding materials were studied. Results of the measurements allowed many advances to be made in the program, ultimately resulting in good agreement between the theory and experiment. 3 refs., 6 figs

Proceedings of the 6th symposium on advanced photon research

International Nuclear Information System (INIS)

2005-06-01

The 6th Symposium on Advanced Photon Research was held at JAERI-Kansai in Kyoto on November 4-5, 2004. The symposium has been held once a year since 1999, to promote the advanced photon research through speeches, information exchanges, discussion by researchers on the front line of advanced photon research in Japan and abroad, not only reports of latest research results and plans at Advanced Photon Research Center. The numbers of speeches were 16, including 5 invited speeches, and the numbers of poster presentations were 56, including the report of presentations and cooperative research and joint research performed in FY2003. The 56 of the presented papers are indexed individually. (J.P.N.)

Photon-Photon Collisions -- Past and Future

International Nuclear Information System (INIS)

Brodsky, Stanley J.

2005-01-01

I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy γγ and eγ tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy γγ collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider

Three-level system driven by delayed pulses of finite duration

International Nuclear Information System (INIS)

Ishkhanyan, Artur; Suominen, Kalle-Antti

2002-01-01

We find the exact solution to the three-state problem for a class of intuitive and counterintuitive sequences of delayed pulses of finite duration in terms of the Clausen's generalized hypergeometric function, which reduces to simple analytic expressions, involving elementary functions only, for final occupation probabilities. These analytic results show that the sequence of delayed pulses, independently of the pulse order and applied detunings, can completely remove the population from the initially populated state (thus creating a quantum superposition of two other involved states). This conclusion extends the original result of Vitanov and Stenholm [Phys. Rev. A 55, 648 (1997)], to the case of nonzero two-photon detuning and more general pulse shapes

Where are photons created in parametric down-conversion? On the control of the spatio–temporal properties of biphoton states

International Nuclear Information System (INIS)

Büse, A; Tischler, N; Juan, M L; Molina-Terriza, G

2015-01-01

In spontaneous parametric down-conversion, pairs of photons are known to be created coherently and with equal probability over the entire length of the crystal. Then, there is no particular position in the crystal where a photon pair is created. We make the seemingly contradictory observation that the time delay between the photons in the pair depends on the distance from the crystal to the collection lens, as if the photons were actually collected preferentially from a particular position in the crystal. We resolve this contradiction by showing that the spatio–temporal correlations critically affect the temporal properties of the pair of photons. The theoretical model we present matches all our experimental results. We expect this to have important implications for experiments that require indistinguishable photons. (paper)

Multiple gamma lines from semi-annihilation

International Nuclear Information System (INIS)

D'Eramo, Francesco; McCullough, Matthew; Thaler, Jesse

2013-01-01

Hints in the Fermi data for a 130 GeV gamma line from the galactic center have ignited interest in potential gamma line signatures of dark matter. Explanations of this line based on dark matter annihilation face a parametric tension since they often rely on large enhancements of loop-suppressed cross sections. In this paper, we pursue an alternative possibility that dark matter gamma lines could arise from ''semi-annihilation'' among multiple dark sector states. The semi-annihilation reaction ψ i ψ j → ψ k γ with a single final state photon is typically enhanced relative to ordinary annihilation ψ i ψ-bar i → γγ into photon pairs. Semi-annihilation allows for a wide range of dark matter masses compared to the fixed mass value required by annihilation, opening the possibility to explain potential dark matter signatures at higher energies. The most striking prediction of semi-annihilation is the presence of multiple gamma lines, with as many as order N 3 lines possible for N dark sector states, allowing for dark sector spectroscopy. A smoking gun signature arises in the simplest case of degenerate dark matter, where a strong semi-annihilation line at 130 GeV would be accompanied by a weaker annihilation line at 173 GeV. As a proof of principle, we construct two explicit models of dark matter semi-annihilation, one based on non-Abelian vector dark matter and the other based on retrofitting Rayleigh dark matter

Tutorial on X-ray photon counting detector characterization.

Science.gov (United States)

Ren, Liqiang; Zheng, Bin; Liu, Hong

2018-01-01

Recent advances in photon counting detection technology have led to significant research interest in X-ray imaging. As a tutorial level review, this paper covers a wide range of aspects related to X-ray photon counting detector characterization. The tutorial begins with a detailed description of the working principle and operating modes of a pixelated X-ray photon counting detector with basic architecture and detection mechanism. Currently available methods and techniques for charactering major aspects including energy response, noise floor, energy resolution, count rate performance (detector efficiency), and charge sharing effect of photon counting detectors are comprehensively reviewed. Other characterization aspects such as point spread function (PSF), line spread function (LSF), contrast transfer function (CTF), modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), bias voltage, radiation damage, and polarization effect are also remarked. A cadmium telluride (CdTe) pixelated photon counting detector is employed for part of the characterization demonstration and the results are presented. This review can serve as a tutorial for X-ray imaging researchers and investigators to understand, operate, characterize, and optimize photon counting detectors for a variety of applications.

A MWPC with a cathode coupled delay line read-out as radioactivity detector for DNA repair studies

International Nuclear Information System (INIS)

Bellazzini, R.; Del Guerra, A.; Massai, M.M.; Ragadini, M.; Spandre, G.; Tonelli, G.

1981-01-01

A non selective method for the isolation of DNA repair-deficient mutants in mammalian cells is discussed. The method requires radioactive labelling of the short DNA sequences synthesized during repair of damaged regions. Mutants should be recognized by the absence of radioactive incorporation into their DNA. A multiwire proportional chamber (MWPC) is proposed as a suitable radioactivity detector. The performance of a MWPC prototype with a cathode coupled delay line read-out is described and is shown to be adequate for this application. The main advantages of a MWPC are reviewed with respect to other methods used for β - radioactivity counting of biological samples, such as liquid scintillators or autoradiography: the proposed detection method is non destructive for the cells, which are being kept alive for further biological studies, furthermore many cell clones can be screened within a reasonable time. (orig.)

Photon Collider Physics with Real Photon Beams

International Nuclear Information System (INIS)

Gronberg, J; Asztalos, S

2005-01-01

Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e + e - collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two

Spontaneous emission spectrum from a V-type three-level atom in a double-band photonic crystal

International Nuclear Information System (INIS)

Zhang Han Zhuang; Tang Sing Hai; Dong Po; He Jun

2002-01-01

The spontaneous emission spectrum from a V-type three-level atom embedded in a double-band photonic band gap (PBG) material has been investigated for the first time. Most interestingly it is shown that there is not only a black dark line, but also a narrow spontaneous line near the edges of the double photonic band. The positions of the dark line and narrow spontaneous line are near the transition from an empty upper level to a lower level. The lines stem from destructive and constructive quantum interferences, which induce population transfer between the two upper levels, in the PBG reservoirs. The effects of system parameters on the interference have been discussed in detail

Controllable scattering of photons in a one-dimensional resonator waveguide

Science.gov (United States)

Sun, C. P.; Zhou, L.; Gong, Z. R.; Liu, Y. X.; Nori, F.

2009-03-01

We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. [4pt] L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons in a 1D resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). URL: http://link.aps.org/abstract/PRL/v101/e100501

Stopping single photons in one-dimensional circuit quantum electrodynamics systems

International Nuclear Information System (INIS)

Shen, J.-T.; Povinelli, M. L.; Sandhu, Sunil; Fan Shanhui

2007-01-01

We propose a mechanism to stop and time reverse single photons in one-dimensional circuit quantum electrodynamics systems. As a concrete example, we exploit the large tunability of the superconducting charge quantum bit (charge qubit) to predict one-photon transport properties in multiple-qubit systems with dynamically controlled transition frequencies. In particular, two qubits coupled to a waveguide give rise to a single-photon transmission line shape that is analogous to electromagnetically induced transparency in atomic systems. Furthermore, by cascading double-qubit structures to form an array and dynamically controlling the qubit transition frequencies, a single photon can be stopped, stored, and time reversed. With a properly designed array, two photons can be stopped and stored in the system at the same time. Moreover, the unit cell of the array can be designed to be of deep subwavelength scale, miniaturizing the circuit

First experimental observation of double-photon Compton scattering using single gamma detector

International Nuclear Information System (INIS)

Sandhu, B.S.; Saddi, M.B.; Singh, B.; Ghumman, B.S.

2003-01-01

Full text: The phenomenon of double-photon Compton scattering has been successfully observed using single gamma detector, a technique avoiding the use of complicated slow-fast coincidence set-up used till now for observing this higher order process. Here doubly differentiated collision cross-section integrated over direction of one of the two final photons, the direction of other one being kept fixed, has been measured experimentally for 0.662 MeV incident gamma photons. The energy spectra of the detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The present results are in agreement with theory of this process

Hadron production in photon-photon collisions

International Nuclear Information System (INIS)

Pandita, P.N.; Singh, Y.

1976-01-01

We analyze deep-inelastic photon-photon collisions via the two-photon mechanism in electron-positron (-electron) colliding beams in a form especially suitable for experimental analysis. It is shown that by a helicity analysis similar to that used in electroproduction experiments, we can separate five of the eight structure functions describing the process γ* + γ* → hadrons. The helicity cross sections for this process and for the process with one real photon (inelastic electron-photon scattering) are related to structure functions, and are evaluated using quark light-cone algebra. There are anomalous contributions to the structure functions for the inelastic electron-photon scattering which arise both in parton as well as generalized vector-meson-dominance models. This suggests a connection between these two types of models for photon-photon scattering. Further, we use vector-meson dominance to construct a sum rule for sigma/sub gamma//sub gamma/ /sub arrow-right/ from which it is estimated that roughly 20% of the cross section should be built up from higher-mass vector states. Using a spectral representation for the total transverse cross section, and the ''aligned-jet'' vector-dominance model we achieve a connection, via a ''correspondence principle,'' with the parton model for the hadron multiplicities in photon-photon collisions. We also comment on inclusive pion multiplicities and the approach to scaling for photon-photon processes in the light-cone algebra

Photons, photon jets and dark photons at 750 GeV and beyond

International Nuclear Information System (INIS)

Dasgupta, Basudeb; Kopp, Joachim

2016-03-01

In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to ''photon jets''. For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance S → γγ can be mimicked by a process of the form pp → S → aa → 4γ, where S is a new scalar with a mass of 750 GeV and a is a light pseudoscalar decaying to two collinear photons. Photon jets can be distinguished from isolated photons by exploiting the fact that a large fraction of photons convert to an e + e - pair inside the inner detector. In this note, we quantify this discrimination power, and we study how the sensitivity of future searches differs for photon jets compared to isolated photons. We also investigate how our results depend on the lifetime of the particle(s) decaying to the photon jet. Finally, we discuss the extension to S → A'A' → e + e - e + e - , where there are no photons at all but the dark photon A' decays to e + e - pairs. Our results will be useful in future studies of the putative 750 GeV signal, but also more generally in any new physics search involving hard photons.

Inverse photon-photon processes

International Nuclear Information System (INIS)

Carimalo, C.; Crozon, M.; Kesler, P.; Parisi, J.

1981-12-01

We here consider inverse photon-photon processes, i.e. AB → γγX (where A, B are hadrons, in particular protons or antiprotons), at high energies. As regards the production of a γγ continuum, we show that, under specific conditions the study of such processes might provide some information on the subprocess gg γγ, involving a quark box. It is also suggested to use those processes in order to systematically look for heavy C = + structures (quarkonium states, gluonia, etc.) showing up in the γγ channel. Inverse photon-photon processes might thus become a new and fertile area of investigation in high-energy physics, provided the difficult problem of discriminating between direct photons and indirect ones can be handled in a satisfactory way

All-Optical Switching in Photonic Crystal Cavities

DEFF Research Database (Denmark)

Heuck, Mikkel

All-Optical switching in photonic crystal waveguide-cavity structures is studied predominantly theoretically and numerically, but also from an experimental point of view. We have calculated the first order perturbations to the resonance frequency and decay rate of cavity modes, using a mathematical...... exhibiting Fano resonances. These devices were predicted to be superior to structures with the more well-known Lorentzian line shape in terms of energy consumption and switching contrast. Finally, the mathematical framework of optimal control theory was employed as a general setting, in which the optical...... faster than the photon lifetime by utilizing interference effects....

Photonic crystal Fano lasers and Fano switches

DEFF Research Database (Denmark)

Mørk, Jesper; Yu, Yi; Bekele, Dagmawi Alemayehu

2017-01-01

We show that Fano resonances can be realized in photonic crystal membrane structures by coupling line-defect waveguides and point-defect nanocavities. The Fano resonance can be exploited to realize optical switches with very small switching energy, as well as Fano lasers, that can generate short...

The recommendation of line-balancing improvement on MCM product line 1 using genetics algorithm and moodie young at XYZ Company, Co.

Science.gov (United States)

Sriwana, I. K.; Marie, I. A.; Mangala, D.

2017-12-01

Kencana Gemilang, Co. is one electronics industry engaging in the manufacture sector. This company manufactures and assembles household electronic products, such as rice cooker, fan, iron, blender, etc. The company deals with an issue of underachievement of an established production target on MCM products line 1. This study aimed to calculate line efficiencies, delay times, and initial line smoothness indexes. The research was carried out by means of depicting a precedence diagram and gathering time data of each work element followed by examination and calculation of standard time as well as line balancing using methods of Moodie Young and Generics Algorithm. Based on results of calculation, better line balancing than the existing initial conditions, i.e. improvement in the line efficiency by 18.39%, deterioration in balanced delay by 28.39%, and deterioration of a smoothness index by 23.85% was obtained.

Photon-photon collisions

International Nuclear Information System (INIS)

Burke, D.L.

1982-10-01

Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved

Photon-photon collisions

International Nuclear Information System (INIS)

Haissinski, J.

1986-06-01

The discussions presented in this paper deal with the following points: distinctive features of gamma-gamma collisions; related processes; photon-photon elastic scattering in the continuum and γγ →gg; total cross section; γγ → V 1 V 2 (V=vector meson); radiative width measurements and light meson spectroscopy; exclusive channels at large /t/; jets and inclusive particle distribution in γγ collisions; and, the photon structure function F γ 2

Photon Factory activity report, 1987

International Nuclear Information System (INIS)

1987-01-01

The Photon Factory made great strides in 1987. The low emittance operation of the PF ring was achieved in March, and resulted favorably in the increase of brilliance from 2 to 20 times for all the beam lines with high beam stability. At the same time, the installation of inserted devices was under way for all available straight sections of the ring. A 54-pole wiggler-undulator has been commissioned at BL-16. The devices to be inserted in the near future are a multipole wiggler for BL-13, an undulator for BL-19, and an undulator for circular polarized radiation at BL-28. The construction of beam lines continued, and four new beam lines, BL-6, BL-9, BL-16 and BL-17, are now in operation, BL-13 and BL-19 are under construction, and BL-3, BL-5, BL-18, BL-20 and BL-28 are in the design stage. Since its inauguration with four beam lines in 1982, the Photon Factory has grown rapidly, and approaches the goal of operating the PF ring with positrons in full use of its 24 beam ports and the straight sections for inserted devices. The total operation time was limited to 3,000 hours by the budget for fiscal year 1987, and about 80 % of the operation hours were devoted to the experiments of users. The nearly perfect operation of the 400 m long linac has continued in 1987, and has supplied both electrons and positrons to the TRISTAN collision experiment. The light source of a 2.5 GeV electron storage ring was normally operated. (Kako, I.)

Design and development of radiation absorber for sighting beam line

International Nuclear Information System (INIS)

Sridhar, R.; Shukla, S.K.

2005-01-01

During the commissioning of Indus-2 , it is necessary to view the synchrotron radiation that will be emanating from the dipole exit ports. The 10 0 beam line from dipole 11 was earmarked for sighting beam line. The synchrotron radiation power density would be around 340 watts on the photon absorber inside the radiation absorber module, at the specified beam power of Indus-2. The beam striking on this photon absorber produces x-rays and Bremsstrahlung radiation. These are to be stopped and absorbed by radiation absorber. The photon absorber and the radiation absorber are integrated in a single vacuum chamber and actuated by a pneumatic cylinder connected using a bellow. Radiation absorber was needed to isolate the diagnostic components and to protect them from radiation a well as heat when they were not in use. The paper describes the design, calculation and development of the dynamic photon cum radiation absorber. The ultimate vacuum performance is also described. (author)

Slow-light-enhanced gain in active photonic crystal waveguides

DEFF Research Database (Denmark)

Ek, Sara; Hansen, Per Lunnemann; Chen, Yaohui

2014-01-01

Passive photonic crystals have been shown to exhibit a multitude of interesting phenomena, including slow-light propagation in line-defect waveguides. It was suggested that by incorporating an active material in the waveguide, slow light could be used to enhance the effective gain of the material......, which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experi- mentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic...... crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar...

Slow and fast light effects and their applications to microwave photonics using semiconductor optical amplifiers

DEFF Research Database (Denmark)

Sales, Salvador; Xue, Weiqi; Mørk, Jesper

2010-01-01

We provide a comprehensive review of the application of slow and fast light (SFL) techniques to the field of microwave photonics. Basic principles leading to the implementation of phase shifting and true time delay operations which are instrumental in this field are first considered. We then focus....... Finally, the main results obtained for several microwave photonic applications such as filtering, arbitrary waveform generation and optoelectronic scillators (OEOs)are reviewed, and other directions for future research in the field are discussed....

Ultrabright, narrow-band photon-pair source for atomic quantum memories

Science.gov (United States)

Tsai, Pin-Ju; Chen, Ying-Cheng

2018-06-01

We demonstrate an ultrabright, narrow-band and frequency-tunable photon-pair source based on cavity-enhanced spontaneous parametric down conversion (SPDC) which is compatible with atomic transition of rubidium D 2-line (780 nm) or cesium D 2-line (852 nm). With the pump beam alternating between a high and a low power phase, the output is switching between the optical parametric oscillator (OPO) and photon-pair generation mode. We utilize the OPO output light to lock the cavity length to maintain the double resonances of signal and idler, as well as to lock the signal frequency to cesium atomic transition. With a type-II phase matching and a double-passed pump scheme such that the cluster frequency spacing is larger than the SPDC bandwidth, the photon-pair output is in a nearly single-mode operation as confirmed by a scanning Fabry–Perot interferometer with its output detected by a photomultiplier. The achieved generation and detection rates are 7.24× {10}5 and 6142 s‑1 mW‑1, respectively. The correlation time of the photon pair is 21.6(2.2) ns, corresponding to a bandwidth of 2π × 6.6(6) MHz. The spectral brightness is 1.06× {10}5 s‑1 mW‑1 MHz‑1. This is a relatively high value under a single-mode operation with the cavity-SPDC scheme. The generated single photons can be readily used in experiments related to atomic quantum memories.

Multi-photon transitions and Rabi resonance in continuous wave EPR.

Science.gov (United States)

Saiko, Alexander P; Fedaruk, Ryhor; Markevich, Siarhei A

2015-10-01

The study of microwave-radiofrequency multi-photon transitions in continuous wave (CW) EPR spectroscopy is extended to a Rabi resonance condition, when the radio frequency of the magnetic-field modulation matches the Rabi frequency of a spin system in the microwave field. Using the non-secular perturbation theory based on the Bogoliubov averaging method, the analytical description of the response of the spin system is derived for all modulation frequency harmonics. When the modulation frequency exceeds the EPR linewidth, multi-photon transitions result in sidebands in absorption EPR spectra measured with phase-sensitive detection at any harmonic. The saturation of different-order multi-photon transitions is shown to be significantly different and to be sensitive to the Rabi resonance. The noticeable frequency shifts of sidebands are found to be the signatures of this resonance. The inversion of two-photon lines in some spectral intervals of the out-of-phase first-harmonic signal is predicted under passage through the Rabi resonance. The inversion indicates the transition from absorption to stimulated emission or vice versa, depending on the sideband. The manifestation of the primary and secondary Rabi resonance is also demonstrated in the time evolution of steady-state EPR signals formed by all harmonics of the modulation frequency. Our results provide a theoretical framework for future developments in multi-photon CW EPR spectroscopy, which can be useful for samples with long spin relaxation times and extremely narrow EPR lines. Copyright © 2015 Elsevier Inc. All rights reserved.

Extraordinary wavelength reduction in terahertz graphene-cladded photonic crystal slabs

Science.gov (United States)

Williamson, Ian A. D.; Mousavi, S. Hossein; Wang, Zheng

2016-01-01

Photonic crystal slabs have been widely used in nanophotonics for light confinement, dispersion engineering, nonlinearity enhancement, and other unusual effects arising from their structural periodicity. Sub-micron device sizes and mode volumes are routine for silicon-based photonic crystal slabs, however spectrally they are limited to operate in the near infrared. Here, we show that two single-layer graphene sheets allow silicon photonic crystal slabs with submicron periodicity to operate in the terahertz regime, with an extreme 100× wavelength reduction from graphene’s large kinetic inductance. The atomically thin graphene further leads to excellent out-of-plane confinement, and consequently photonic-crystal-slab band structures that closely resemble those of ideal two-dimensional photonic crystals, with broad band gaps even when the slab thickness approaches zero. The overall photonic band structure not only scales with the graphene Fermi level, but more importantly scales to lower frequencies with reduced slab thickness. Just like ideal 2D photonic crystals, graphene-cladded photonic crystal slabs confine light along line defects, forming waveguides with the propagation lengths on the order of tens of lattice constants. The proposed structure opens up the possibility to dramatically reduce the size of terahertz photonic systems by orders of magnitude. PMID:27143314

Two-dimensional 'photon fluid': effective photon-photon interaction and physical realizations

International Nuclear Information System (INIS)

Chiao, R Y; Hansson, T H; Leinaas, J M; Viefers, S

2004-01-01

We describe a recently developed effective theory for atom-mediated photon-photon interactions in a two-dimensional 'photon fluid' confined to a Fabry-Perot resonator. The photons in the lowest longitudinal cavity mode will appear as massive bosons interacting via a renormalized delta-function potential with a strength determined by physical parameters such as the density of atoms and the detuning of the photons relative to the resonance frequency of the atoms. We discuss novel quantum phenomena for photons, such as Bose-Einstein condensation and bound state formation, as well as possible experimental scenarios based on Rydberg atoms in a microwave cavity, or alkali atoms in an optical cavity

Computations of Photon Orbits Emitted by Flares at the ISCO of Accretion Disks Around Rotating Black Holes

Science.gov (United States)

Kazanas, Demosthenes; Fukumura, K.

2009-01-01

We present detailed computations of photon orbits emitted by flares at the ISCO of accretion disks around rotating black holes. We show that for sufficiently large spin parameter, i.e. $a > 0.94 M$, following a flare at ISCO, a sufficient number of photons arrive at an observer after multiple orbits around the black hole, to produce an "photon echo" of constant lag, i.e. independent of the relative phase between the black hole and the observer, of $\\Delta T \\simeq 14 M$. This constant time delay, then, leads to the presence of a QPO in the source power spectrum at a frequency $\

Jet and hadron production in photon-photon collisions

OpenAIRE

Soldner-Rembold, Stefan

1999-01-01

Di-jet and inclusive charged hadron production cross-sections measured in photon-photon collisions by OPAL are compared to NLO pQCD calculations. Jet shapes measured in photon-photon scattering by OPAL, in deep-inelastic ep scattering by H1 and in photon-proton scattering by ZEUS are shown to be consistent in similar kinematic ranges. New results from TOPAZ on prompt photon production in photon-photon interactions are presented.

Continuing research on the classical spiraling photon model

Science.gov (United States)

Li, Hongrui

2014-11-01

Based no the classical spiraling photon model proposed by Hongrui Li, the laws of reflection, refraction of a single photon can be derived. Moreover, the polarization, total reflection, evanescent wave and Goos-Hanchen shift of a single photon can be elucidated. However, this photon model is still unfinished. Especially, the spiraling diameter of a photon is not definite. In this paper, the continuous research works on this new theory are reported. According to the facts that the diffraction limit of light and the smallest diameter of the focal spot of lenses are all equal to the wavelength λ of the light, we can get that the spiraling diameter of a photon equals to the wavelength λ, so we gain that the angle between the linear velocity of the spiraling photon υ and the component of the linear velocity in the forward direction υb is 45°, and the energy of a classical spiraling photon E = (1/2)mυ2 = (1/2)m2c2 = mc2. This coincides with Einstein's mass-energy relation. While it is obtained that the velocity of the evanescent wave in the vacuum is slower than the velocity of light in glass in straight line. In such a way, the optical fiber can slow the light down. In addition, the force analysis of a single photon in optical tweezers system is discussed. And the reason that the laser beam can capture the particle slightly downstream from the focal point can be explained.

Operation of beam line facilities for real-time x-ray studies at Sector 7 of the advanced photon source. Final Report

International Nuclear Information System (INIS)

Clarke, Roy

2003-01-01

This Final Report documents the research accomplishments achieved in the first phase of operations of a new Advanced Photon Source beam line (7-ID MHATT-CAT) dedicated to real-time x-ray studies. The period covered by this report covers the establishment of a world-class facility for time-dependent x-ray studies of materials. During this period many new and innovative research programs were initiated at Sector 7 with support of this grant, most notably using a combination of ultrafast lasers and pulsed synchrotron radiation. This work initiated a new frontier of materials research: namely, the study of the dynamics of materials under extreme conditions of high intensity impulsive laser irradiation

Multiband Photonic Phased-Array Antenna

Science.gov (United States)

Tang, Suning

2015-01-01

A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

Experimental verification of the line-shape distortion in resonance Auger spectra

International Nuclear Information System (INIS)

Aksela, S.; Kukk, E.; Aksela, H.; Svensson, S.

1995-01-01

When the mean excitation energy and the width of a broad photon band are varied the Kr 3d 5/2 -1 5p→4p -2 5p resonance Auger electron lines show strong asymmetry and their average kinetic energies shift. Even extra peaks appear. Our results demonstrate experimentally, for the first time, that the incident photon energy distribution has very crucial importance on the resonance Auger line shape and thus on the reliable data analysis of complicated Auger spectra

Universal continuous-variable quantum computation: Requirement of optical nonlinearity for photon counting

International Nuclear Information System (INIS)

Bartlett, Stephen D.; Sanders, Barry C.

2002-01-01

Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection, and feed-forward, inclusion of ideal photon-counting measurements overcomes this obstacle. These measurements are sometimes described by arrays of beam splitters to distribute the photons across several modes. We show that such a scheme cannot be used to implement ideal photon counting and that such measurements necessarily involve nonlinear evolution. However, this requirement of nonlinearity can be moved ''off-line,'' thereby permitting universal continuous-variable quantum computation with linear optics

Photons, photon jets, and dark photons at 750 GeV and beyond.

Science.gov (United States)

Dasgupta, Basudeb; Kopp, Joachim; Schwaller, Pedro

2016-01-01

In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to "photon jets". For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance [Formula: see text] can be mimicked by a process of the form [Formula: see text], where S is a new scalar with a mass of 750 GeV and a is a light pseudoscalar decaying to two collinear photons. Photon jets can be distinguished from isolated photons by exploiting the fact that a large fraction of photons convert to an [Formula: see text] pair inside the inner detector. In this note, we quantify this discrimination power, and we study how the sensitivity of future searches differs for photon jets compared to isolated photons. We also investigate how our results depend on the lifetime of the particle(s) decaying to the photon jet. Finally, we discuss the extension to [Formula: see text], where there are no photons at all but the dark photon [Formula: see text] decays to [Formula: see text] pairs. Our results will be useful in future studies of the putative 750 GeV signal, but also more generally in any new physics search involving hard photons.

Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

DEFF Research Database (Denmark)

Senturk, O.S.; Hava, A.M.

2011-01-01

This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k...

Requirements and guidelines for NSLS experimental beam line vacuum systems: Revision A

International Nuclear Information System (INIS)

Foerster, C.; Halama, H.; Thomlinson, W.

1986-10-01

Requirements are provided for NSLS beam line front ends and vacuum interlocks. Guidelines are provided for UHV beam line vacuum systems, including materials, vacuum hardware (pumps, valves, and flanges), acoustic delay lines and beam line fast valves, instrumentation, fabrication and testing, and the NSLS cleaning facility. Also discussed are the design review for experimenters' equipment that would be connected to the NSLS and acceptance tests for any beam line to be connected with the ring vacuum. Also appended are a description of the acoustic delay line as well as the NSLS vacuum standards and NSLS procedures

Particle and photon detection for a neutron radiative decay experiment

Energy Technology Data Exchange (ETDEWEB)

Gentile, T.R. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)], E-mail: thomas.gentile@nist.gov; Dewey, M.S.; Mumm, H.P.; Nico, J.S.; Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48109 (United States); Cooper, R.L. [University of Michigan, Ann Arbor, MI 48109 (United States)], E-mail: cooperrl@umich.edu; Fisher, B.M.; Kremsky, I.; Wietfeldt, F.E. [Tulane University, New Orleans, LA 70118 (United States); Kiriluk, K.G.; Beise, E.J. [University of Maryland, College Park, MD 20742 (United States)

2007-08-21

We present the particle and photon detection methods employed in a program to observe neutron radiative beta-decay. The experiment is located at the NG-6 beam line at the National Institute of Standards and Technology Center for Neutron Research. Electrons and protons are guided by a 4.6 T magnetic field and detected by a silicon surface barrier detector. Photons with energies between 15 and 750 keV are registered by a detector consisting of a bismuth germanate scintillator coupled to a large area avalanche photodiode. The photon detector operates at a temperature near 80 K in the bore of a superconducting magnet. We discuss CsI as an alternative scintillator, and avalanche photodiodes for direct detection of photons in the 0.1-10 keV range.

Hadronic photon-photon interactions at high energies

International Nuclear Information System (INIS)

Engel, R.; Siegen Univ.; Ranft, J.

1996-01-01

Photon-photon collisions are investigated in the framework of the two-component Dual Parton Model. The model contains contributions from direct, resolved soft and resolved hard interactions. All free parameters of the model are determined in fits to hadron-hadron and photon-hadron cross section data. The model is shown to agree well to hadron production data from hadron-hadron and photon-hadron collisions. The multiparticle production in hadron-hadron, photon-hadron and photon-photon collisions as predicted by the model is compared. Strong differences are only found as function of the transverse momentum variable. (author)

An integrated single- and two-photon non-diffracting light-sheet microscope

Science.gov (United States)

Lau, Sze Cheung; Chiu, Hoi Chun; Zhao, Luwei; Zhao, Teng; Loy, M. M. T.; Du, Shengwang

2018-04-01

We describe a fluorescence optical microscope with both single-photon and two-photon non-diffracting light-sheet excitations for large volume imaging. With a special design to accommodate two different wavelength ranges (visible: 400-700 nm and near infrared: 800-1200 nm), we combine the line-Bessel sheet (LBS, for single-photon excitation) and the scanning Bessel beam (SBB, for two-photon excitation) light sheet together in a single microscope setup. For a transparent thin sample where the scattering can be ignored, the LBS single-photon excitation is the optimal imaging solution. When the light scattering becomes significant for a deep-cell or deep-tissue imaging, we use SBB light-sheet two-photon excitation with a longer wavelength. We achieved nearly identical lateral/axial resolution of about 350/270 nm for both imagings. This integrated light-sheet microscope may have a wide application for live-cell and live-tissue three-dimensional high-speed imaging.

Survey and alignment of photon factory storage ring at KEK

International Nuclear Information System (INIS)

Araki, A.; Honjo, I.; Katoh, M.; Kamiya, Y.; Kihara, M.

1987-01-01

The heights of the magnets for both the ring and the beam transport line (BT-line) have been periodically measured at the Photon Factory. The accumulated data showed that the ring was considerably declined due to the construction of the large experimental hall and the tunnel of the TRISTAN project, and that the BT-line also sank several centimeters at some locations. These displacements of the magnets produce a significantly large closed orbit distortion and the vertical dispersion

Photon-photon collisions

International Nuclear Information System (INIS)

Field, J.H.

1984-01-01

The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e + e - storage rings. After a complete presentation of the helicity amplitude formalism for the general process e + e - → Xe + e - , various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

Photon-photon collisions

Energy Technology Data Exchange (ETDEWEB)

Brodsky, S.J.

1985-01-01

The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

Photon-photon collisions

International Nuclear Information System (INIS)

Brodsky, S.J.

1985-01-01

The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references

Non-Markovian dynamics of a qubit due to single-photon scattering in a waveguide

Science.gov (United States)

Fang, Yao-Lung L.; Ciccarello, Francesco; Baranger, Harold U.

2018-04-01

We investigate the open dynamics of a qubit due to scattering of a single photon in an infinite or semi-infinite waveguide. Through an exact solution of the time-dependent multi-photon scattering problem, we find the qubit's dynamical map. Tools of open quantum systems theory allow us then to show the general features of this map, find the corresponding non-Linbladian master equation, and assess in a rigorous way its non-Markovian nature. The qubit dynamics has distinctive features that, in particular, do not occur in emission processes. Two fundamental sources of non-Markovianity are present: the finite width of the photon wavepacket and the time delay for propagation between the qubit and the end of the semi-infinite waveguide.

A tale of tails: Photon rates and flow in ultra-relativistic heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

McLerran, Larry [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Physics Dept., China Central Normal University, Wuhan (China); Schenke, Björn, E-mail: bschenke@quark.phy.bnl.gov [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2016-02-15

We consider the possibility that quark and gluon distributions in the medium created in high energy heavy ion collisions may be modified by a power law tail at energies much higher than the temperature. We parametrize such a tail by Tsallis distributions with an exponent motivated by phenomenology. These distributions are characterized by an effective temperature scale that we assume to evolve in time like the temperature for thermal distributions. We find that including such a tail increases the rates for photon production and significantly delays the emission times for photons of a fixed energy. We argue that these effects should modify photon yields and flow patterns in a way that will help the agreement of theoretical calculations with data from LHC and RHIC experiments.

Attosecond relative delay among xenon 5p, 5s, and 4d photoionization

Science.gov (United States)

Magrakvelidze, Maia; Madjet, Mohamed; Chakraborty, Himadri

2017-04-01

Attosecond Wigner-Smith (WS) time delays of the photoemissions of Xe valence 5p, 5s, and core 4d electrons are investigated in details using the time-dependent local density approximation (TDLDA). Electron correlations determine the energy-dependent structures in ionization phases of the dipole channels and in the resulting WS delays at various shape resonances, induced by the collective motion of 4d electrons, and at various Cooper minima. We find that our calculation closely agrees with the streaking measurement for the delay of 4d relative to 5s, and predicts accelerated emission of 5p with respect to 4d as was experimentally observed at similar photon energies for Xe atoms adsorbed on the tungsten surface. This work was supported by the U.S. National Science Foundation.

X-ray heating and ionization of broad-emission-line regions in QSO's and active galaxies

International Nuclear Information System (INIS)

Weisheit, J.C.; Shields, G.A.; Tarter, C.B.

1980-07-01

Absorption of x-rays deep within the broad-line emitting clouds in QSO's and the nuclei of active galaxies creates extensive zones of warm (T approx. 10 4 K), partially ionized N/sub e//N approx. 0.1) gas. Because Lyman alpha photons are trapped in these regions, the x-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. The HI regions plus the HII regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated Lα/Hα line emission ratios between 1 and 2. Enhanced MgII line emission from the HI regions gives rise to integrated MgII/Hα ratios near 0.5. The OI line lambda 8446 is efficiently pumped by trapped Hα photons and in the x-ray heated zone an intensity ratio I (lambda 8446)/I(Hα) approx. < 0.1 is calculated. All of these computed ratios now are in agreement with observations

Microwave-Controlled Generation of Shaped Single Photons in Circuit Quantum Electrodynamics

Directory of Open Access Journals (Sweden)

M. Pechal

2014-10-01

Full Text Available Large-scale quantum information processors or quantum communication networks will require reliable exchange of information between spatially separated nodes. The links connecting these nodes can be established using traveling photons that need to be absorbed at the receiving node with high efficiency. This is achievable by shaping the temporal profile of the photons and absorbing them at the receiver by time reversing the emission process. Here, we demonstrate a scheme for creating shaped microwave photons using a superconducting transmon-type three-level system coupled to a transmission line resonator. In a second-order process induced by a modulated microwave drive, we controllably transfer a single excitation from the third level of the transmon to the resonator and shape the emitted photon. We reconstruct the density matrices of the created single-photon states and show that the photons are antibunched. We also create multipeaked photons with a controlled amplitude and phase. In contrast to similar existing schemes, the one we present here is based solely on microwave drives, enabling operation with fixed frequency transmons.

The TCD50 and regrowth delay assay in human tumor xenografts: Differences and implications

International Nuclear Information System (INIS)

Budach, W.; Budach, V.; Stuschke, M.; Dinges, S.; Sack, H.

1993-01-01

The response to irradiation of five human xenograft cell lines - a malignant paraganglioma, a neurogenic sarcoma, a malignant histiocytoma, a primary lymphoma of the brain, and a squamous cell carcinoma - were tested in nude mice. All mice underwent 5 Gy whole body irradiation prior to xenotransplantation to minimize the residual immune response. The subcutaneous tumors were irradiated at a tumor volume of 120 mm 3 under acutely hypoxic conditions with single doses between 8 Gy and 80 Gy depending on the expected radiation sensitivity of the tumor line. Endpoints of the study were the tumor control dose 50% (TCD 50 ) and the regrowth delay endpoints growth delay, specific growth delay, and the tumor bed effect corrected specific growth delay. Specific growth delay and corrected specific growth delay at 76% of the TCD 50 was used in order to compare the data to previously published data from spheroids. The lowest TCD 50 was found in the lymphoma with 24.9 Gy, whereas the TCD 50 of the soft tissue sarcomas and the squamous cell carcinoma ranged from 57.8 Gy to 65.6 Gy. The isoeffective dose levels for the induction of 30 days growth delay, a specific growth delay of 3, and a corrected specific growth delay of 3 ranged from 15.5 Gy (ECL1) to 37.1 Gy (FADU), from 7.2 Gy (ENE2) to 45.6 Gy (EPG1) and from 9.2 Gy (ENE2) to 37.6 Gy (EPG1), respectively. The corrected specific growth delay at 76% of the TCD 50 was correlated with the number of tumor rescue units per 100 cells in spheroids, which was available for three tumor lines, and with the tumor doubling time in xenografts (n = 5). The TCD 50 values corresponded better to the clinical experience than the regrowth delay data. There was no correlation between TCD 50 and any of the regrowth delay endpoints. This missing correlation was most likely a result of large differences in the number of tumor rescue units in human xenografts of the same size

The Heavy Photon Search beamline and its performance

Energy Technology Data Exchange (ETDEWEB)

Baltzell, N.; Egiyan, H.; Ehrhart, M.; Field, C.; Freyberger, A.; Girod, F.-X.; Holtrop, M.; Jaros, J.; Kalicy, G.; Maruyama, T.; McKinnon, B.; Moffeit, K.; Nelson, T.; Odian, A.; Oriunno, M.; Paremuzyan, R.; Stepanyan, S.; Tiefenback, M.; Uemura, S.; Ungaro, M.; Vance, H.

2017-04-04

The Heavy Photon Search (HPS) is an experiment to search for a hidden sector photon, aka a heavy photon or dark photon, in fixed target electroproduction at the Thomas Jefferson National Accelerator Facility (JLab). The HPS experiment searches for the e+e- decay of the heavy photon with bump hunt and detached vertex strategies using a compact, large acceptance forward spectrometer, consisting of a silicon microstrip detector (SVT) for tracking and vertexing, and a PbWO₄ electromagnetic calorimeter for energy measurement and fast triggering. To achieve large acceptance and good vertexing resolution, the first layer of silicon detectors is placed just 10 cm downstream of the target with the sensor edges only 500 μm above and below the beam. Placing the SVT in such close proximity to the beam puts stringent requirements on the beam profile and beam position stability. As part of an approved engineering run, HPS took data in 2015 and 2016 at 1.05 GeV and 2.3 GeV beam energies, respectively. This paper describes the beam line and its performance during that data taking.

Photon correlation in single-photon frequency upconversion.

Science.gov (United States)

Gu, Xiaorong; Huang, Kun; Pan, Haifeng; Wu, E; Zeng, Heping

2012-01-30

We experimentally investigated the intensity cross-correlation between the upconverted photons and the unconverted photons in the single-photon frequency upconversion process with multi-longitudinal mode pump and signal sources. In theoretical analysis, with this multi-longitudinal mode of both signal and pump sources system, the properties of the signal photons could also be maintained as in the single-mode frequency upconversion system. Experimentally, based on the conversion efficiency of 80.5%, the joint probability of simultaneously detecting at upconverted and unconverted photons showed an anti-correlation as a function of conversion efficiency which indicated the upconverted photons were one-to-one from the signal photons. While due to the coherent state of the signal photons, the intensity cross-correlation function g(2)(0) was shown to be equal to unity at any conversion efficiency, agreeing with the theoretical prediction. This study will benefit the high-speed wavelength-tunable quantum state translation or photonic quantum interface together with the mature frequency tuning or longitudinal mode selection techniques.

The molecular basis for cell cycle delays following ionizing radiation. A review

International Nuclear Information System (INIS)

Maity, A.; McKenna, W.G.; Muschel, R.J.

1994-01-01

Exposure of a wide variety of cells to ionizing (X- or γ-) irradiation results in a division delay which may have several components including a G 1 block, a G 2 arrest or an S phase delay. The G 1 arrest is absent in many cells lines, and the S phase delay is typically seen following relatively high doses (>5 Gy). In contrast, the G 2 arrest is seen in virtually all eukaryotic cells and occurs following high and low doses, even under 1 Gy. The mechanism underlying the G 2 arrest may involve suppression of cyclin B1 mRNA and/or protein in some cell lines and tyrosine phosphorylation of p34 cdc2 in others. Similar mechanisms are likely to be operative in the G 2 arrest induced by various chemotherapeutic agents including nitrogen mustard and etoposide. The upstream signal transduction pathways involved in the G 2 arrest following ionizing radiation remain obscure in mammalian cells; however, in the budding yeast the rad9 gene and in the fission yeast the chk1/rad27 gene are involved. There is evidence indicating that shortening of the G 2 arrest results in decreased survival which has led to the hypothesis that during this block, cells repair damaged DNA following exposure to genotoxic agents. In cell lines examined to date, wildtype p53 is required for the G 1 arrest following ionizing radiation. The gadd45 gene may also have a role in this arrest. Elimination of the G 1 arrest leads to no change in survival following radiation in some cell lines and increased radioresistance in others. It has been suggested that this induction of radioresistance in certain cell lines is due to loss of the ability to undergo apoptosis. Relatively little is known about the mechanism underlying the S phase delay. This delay is due to a depression in the rate of DNA synthesis and has both a slow and a fast component. In some cells the S phase delay can be abolished by staurosporine, suggesting involvement of a protein kinase. Understanding the molecular mechanisms behind these delays

Use of a multilayer printed circuit board as the position sensing electrode in an MWPC

International Nuclear Information System (INIS)

Barbosa, A.F.

1995-01-01

An X-ray gas position sensitive detector (PSD) is described. The detector makes use of a single electrode, the X and Y cathode, to sense the electric charge induced by the avalanches generated after the absorption of X-ray photons in a multiwire proportional counter (MWPC). Two-dimensional (2D) localization of photons is achieved by associating one delay line to each coordinate. The delay lines are directly coupled to the X and Y cathode, so that the propagation time of electric pulses can be related to the corresponding avalanche position. Since the position encoding does not involve wires, the anode is the only wire electrode present in the detector, used for collecting the avalanche electrons. (orig.)

Spectrum optimization-based chaotification using time-delay feedback control

International Nuclear Information System (INIS)

Zhou Jiaxi; Xu Daolin; Zhang Jing; Liu Chunrong

2012-01-01

Highlights: ► A time-delay feedback controller is designed for chaotification. ► A spectrum optimization method is proposed to determine chaotification parameters. ► Numerical examples verify the spectrum optimization- based chaotification method. ► Engineering application in line spectrum reconfiguration is demonstrated. - Abstract: In this paper, a spectrum optimization method is developed for chaotification in conjunction with an application in line spectrum reconfiguration. A key performance index (the objective function) based on Fourier spectrum is specially devised with the idea of suppressing spectrum spikes and broadening frequency band. Minimization of the index empowered by a genetic algorithm enables to locate favorable parameters of the time-delay feedback controller, by which a line spectrum of harmonic vibration can be transformed into a broad-band continuous spectrum of chaotic motion. Numerical simulations are carried out to verify the feasibility of the method and to demonstrate its effectiveness of chaotifying a 2-DOFs linear mechanical system.

Understanding interference experiments with polarized light through photon trajectories

International Nuclear Information System (INIS)

Sanz, A.S.; Davidovic, M.; Bozic, M.; Miret-Artes, S.

2010-01-01

Bohmian mechanics allows to visualize and understand the quantum-mechanical behavior of massive particles in terms of trajectories. As shown by Bialynicki-Birula, Electromagnetism also admits a hydrodynamical formulation when the existence of a wave function for photons (properly defined) is assumed. This formulation thus provides an alternative interpretation of optical phenomena in terms of photon trajectories, whose flow yields a pictorial view of the evolution of the electromagnetic energy density in configuration space. This trajectory-based theoretical framework is considered here to study and analyze the outcome from Young-type diffraction experiments within the context of the Arago-Fresnel laws. More specifically, photon trajectories in the region behind the two slits are obtained in the case where the slits are illuminated by a polarized monochromatic plane wave. Expressions to determine electromagnetic energy flow lines and photon trajectories within this scenario are provided, as well as a procedure to compute them in the particular case of gratings totally transparent inside the slits and completely absorbing outside them. As is shown, the electromagnetic energy flow lines obtained allow to monitor at each point of space the behavior of the electromagnetic energy flow and, therefore, to evaluate the effects caused on it by the presence (right behind each slit) of polarizers with the same or different polarization axes. This leads to a trajectory-based picture of the Arago-Fresnel laws for the interference of polarized light.

Effect of applied voltage and inter-pulse delay in spark-assisted LIBS

Science.gov (United States)

Robledo-Martinez, A.; Sobral, H.; Garcia-Villarreal, A.

2018-06-01

We report the results obtained in an investigation on the effect of the time delay between the laser and electrical pulses in a spark-assisted laser-induced breakdown spectroscopy (LIBS) experiment. The electrical discharge is produced by the discharge of a charged coaxial cable. This arrangement produces a fast unipolar current pulse (500 ns) that applies high power ( 600 kW) to the laser ablation plasma. The delay between the laser pulse and the electric pulse can be controlled at will in order to find the optimal time in terms of enhancement of the emitted lines. It was found that the application of the high voltage pulse enhances the ionic lines emitted by up to two orders of magnitude. An additional enhancement by a factor of 2-4 can be obtained delaying the application of the electric pulse by a time of 0.6-20 μs. In the tests it was noticed that the ionic lines were found to be clearly responsive to increments in the applied electric energy while the neutral lines did so marginally. Our results show that the intensification of the lines is mainly due to reheating of the ablation plasma as the application of the electrical pulse increments the temperature of the ablation plasma by about 50%. It is demonstrated that the present technique is an efficient way of intensifying the lines emitted without incurring in additional damage to the sample.

First corrections to hyperfine splitting and the Lamb shift induced by diagrams with two external photons and second-order radiative insertions in the electron line

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1994-01-01

Contributions to hyperfine splitting (HFS) and to the Lamb shift on the order of α 2 (Zα) 5 induced by graphs with two radiative photons inserted into the electron line are considered. It is shown that this gauge-invariant set of diagrams, which give corrections of the considered order, consists of nineteen topologically different diagrams. Contributions to both HFS and the Lamb shift induced by graphs containing the one-loop electron self-energy as a subgraph and by the graph containing two one-loop vertices are obtained. 15 refs., 3 figs

Theory of the effect of odd-photon destructive interference on optical shifts in resonantly enhanced multiphoton excitation and ionization

International Nuclear Information System (INIS)

Payne, M.G.; Deng, L.; Garrett, W.R.

1998-01-01

We present a theory for two- and three-photon excitation, optical shifting, and four-wave mixing when a first laser is tuned onto, or near, a two-photon resonance and a second much more intense laser is tuned near or on resonance between the two-photon resonance and a second excited state. When the second excited state has a dipole-allowed transition back to the ground state and the concentration is sufficiently high, a destructive interference is produced between three-photon coupling of the ground state and the second excited state and one-photon coupling between the same states by the internally generated four-wave mixing field. This interference leads to several striking effects. For instance, as the onset of the interference occurs, the optical shifts in the two-photon resonance excitation line shape become smaller in copropagating geometry so that the line shapes for multiphoton ionization enhanced by the two-photon resonance eventually become unaffected by the second laser. In the same range of concentrations the four-wave mixing field evolves to a concentration-independent intensity. With counterpropagating laser beams the line shape exhibits normal optical shifts like those observed for both copropagating and counterpropagating laser beams at very low concentrations. The theoretical work presented here extends our earlier works by including the effect of laser bandwidth and by removing the restriction of having the second laser be tuned far from three-photon resonance. In this way we have now included, as a special case, the effect of both laser bandwidth and interference on laser-induced transparency. Unlike other effects related to odd-photon destructive interference, the effect of a broad bandwidth is to bring about the predicted effects at much lower concentrations. Studies in rubidium show good agreement between theory and experiment for both ionization line shapes and four-wave mixing intensity as a function of concentration. copyright 1998 The

Highly localized distributed Brillouin scattering response in a photonic integrated circuit

Science.gov (United States)

Zarifi, Atiyeh; Stiller, Birgit; Merklein, Moritz; Li, Neuton; Vu, Khu; Choi, Duk-Yong; Ma, Pan; Madden, Stephen J.; Eggleton, Benjamin J.

2018-03-01

The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS) has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

Highly localized distributed Brillouin scattering response in a photonic integrated circuit

Directory of Open Access Journals (Sweden)

Atiyeh Zarifi

2018-03-01

Full Text Available The interaction of optical and acoustic waves via stimulated Brillouin scattering (SBS has recently reached on-chip platforms, which has opened new fields of applications ranging from integrated microwave photonics and on-chip narrow-linewidth lasers, to phonon-based optical delay and signal processing schemes. Since SBS is an effect that scales exponentially with interaction length, on-chip implementation on a short length scale is challenging, requiring carefully designed waveguides with optimized opto-acoustic overlap. In this work, we use the principle of Brillouin optical correlation domain analysis to locally measure the SBS spectrum with high spatial resolution of 800 μm and perform a distributed measurement of the Brillouin spectrum along a spiral waveguide in a photonic integrated circuit. This approach gives access to local opto-acoustic properties of the waveguides, including the Brillouin frequency shift and linewidth, essential information for the further development of high quality photonic-phononic waveguides for SBS applications.

Break-before-make CMOS inverter for power-efficient delay implementation.

Science.gov (United States)

Puhan, Janez; Raič, Dušan; Tuma, Tadej; Bűrmen, Árpád

2014-01-01

A modified static CMOS inverter with two inputs and two outputs is proposed to reduce short-circuit current in order to increment delay and reduce power overhead where slow operation is required. The circuit is based on bidirectional delay element connected in series with the PMOS and NMOS switching transistors. It provides differences in the dynamic response so that the direct-path current in the next stage is reduced. The switching transistors are never ON at the same time. Characteristics of various delay element implementations are presented and verified by circuit simulations. Global optimization procedure is used to obtain the most power-efficient transistor sizing. The performance of the modified CMOS inverter chain is compared to standard implementation for various delays. The energy (charge) per delay is reduced up to 40%. The use of the proposed delay element is demonstrated by implementing a low-power delay line and a leading-edge detector cell.

Beta-delayed neutron decay of $^{33}$Na

CERN Document Server

Radivojevic, Z; Caurier, E; Cederkäll, J; Courtin, S; Dessagne, P; Jokinen, A; Knipper, A; Le Scornet, G; Lyapin, V G; Miehé, C; Nowacki, F; Nummela, S; Oinonen, M; Poirier, E; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

2002-01-01

Beta-delayed neutron decay of /sup 33/Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the /sup 33/Na decay, showing evidence for strong feeding of states at about 4 MeV in /sup 33/Mg. By simultaneous beta - gamma -n counting the delayed neutron emission probabilities P/sub 1n/ = 47(6)% and P /sub 2n/ = 13(3)% were determined. The half-life value for /sup 33 /Na, T/sub 1/2/ = 8.0(3) ms, was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting. (21 refs).

Proceedings of the third users meeting for the Advanced Photon Source

Energy Technology Data Exchange (ETDEWEB)

1990-06-01

The Third Users Meetings for the Advanced Photon Source, held on October 12--13, 1989, at Argonne National Laboratory, brought together scientists and engineers from industry, universities, and national laboratories to review the status of the facility and make plans for its use. The presentations documented in these proceedings include overviews of the project status and the user access policy; updates on several fundamental research efforts that make use of synchrotron radiation; reports on insertion-device R D and beam line design activities; cost and manpower estimates for beam line construction; and a panel discussion on strategies for developing and managing Collaborative Access Teams. The actions taken at the 1989 Business Meeting of the Advanced Photon Source Users Organization are also documented.

Proceedings of the third users meeting for the Advanced Photon Source

International Nuclear Information System (INIS)

1990-06-01

The Third Users Meetings for the Advanced Photon Source, held on October 12--13, 1989, at Argonne National Laboratory, brought together scientists and engineers from industry, universities, and national laboratories to review the status of the facility and make plans for its use. The presentations documented in these proceedings include overviews of the project status and the user access policy; updates on several fundamental research efforts that make use of synchrotron radiation; reports on insertion-device R ampersand D and beam line design activities; cost and manpower estimates for beam line construction; and a panel discussion on strategies for developing and managing Collaborative Access Teams. The actions taken at the 1989 Business Meeting of the Advanced Photon Source Users Organization are also documented

Line broadening by focusing

International Nuclear Information System (INIS)

Brito, A.L. de; Jabs, A.

1983-01-01

It is pointed out that the spectral width of a quasi-monochromatic light beam broadens when the beam is focused. A quantitative formula for this broadening is derived from classical wave theory. The effect is shown to explain some experiments on laser beams done by E. Panarella which that author has explained under the ad-hoc hypothesis that the frequency of the photons changes along with the intensity of the light beam. The line broadening by focusing might also contribute to gas ionization by incident light when the ionization potential is well above the mean photon energy. Some remarks are made on some direct applications of the Heisenberg relations in comparison with our treatment. (Author) [pt

Photon-photon and photon-hadron processes in relativistic heavy ion collisions

International Nuclear Information System (INIS)

Baron, N.C.

1993-11-01

Photon-photon and photon-hadron interactions in relativistic heavy ion collisions are studied in the framework of the impact parameter dependent equivalent photon approximation. Improvements of this method, like formfactor inclusion and geometrical modifications are developed. In disruptive relativistic heavy ion collisions where the heavy ions overlapp during the collision, electromagnetic processes are an important background to other mechanisms. In peripheral (non-disruptive) relativistic heavy ion collisions where the ions pass each other without strong interactions, the electromagnetic processes can be studied in their pure form. The lepton pair production is an important diagnostic tool in relativistic heavy ion collisions. The coherent γγ lepton pair production is therefore extensively studied in disruptive but also in non-disruptive collisions. The effects of strong interactions on the coherent γγ lepton pair production in disruptive collisions are discussed in terms of a simple stopping model. Coherent γγ dielectron production contributes to the dilepton production in high energy hadron-hadron collisions. As an example, the coherent dielectron production in π - p collisions is studied in terms of the equivalent photon approximation. Peripheral ultrarelativistic heavy ion collisions open up new possibilities for γγ physics. Taking into account γA background reactions, typical γγ processes in the relevant invariant mass ranges are discussed. The extreme high energy part of the equivalent photon spectrum leads to hard photon-parton reactions. As a potential tool to investigate the gluon distribution function of nucleons, thee q anti q production via the γg fusion in ultrarelativistic heavy ion collisions is studied. It is the purpose of this work to investigate how photon-photon and photon-hadron reactions in relativistic heavy ion collisions may contribute to the understanding of QCD and the standard model. (orig.) [de

Radiation-Resistant Photon-Counting Detector Package Providing Sub-ps Stability for Laser Time Transfer in Space

Science.gov (United States)

Prochzaka, Ivan; Kodat, Jan; Blazej, Josef; Sun, Xiaoli (Editor)

2015-01-01

We are reporting on a design, construction and performance of photon-counting detector packages based on silicon avalanche photodiodes. These photon-counting devices have been optimized for extremely high stability of their detection delay. The detectors have been designed for future applications in fundamental metrology and optical time transfer in space. The detectors have been qualified for operation in space missions. The exceptional radiation tolerance of the detection chip itself and of all critical components of a detector package has been verified in a series of experiments.

Simulating three-dimensional nonthermal high-energy photon emission in colliding-wind binaries

Energy Technology Data Exchange (ETDEWEB)

Reitberger, K.; Kissmann, R.; Reimer, A.; Reimer, O., E-mail: klaus.reitberger@uibk.ac.at [Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck (Austria)

2014-07-01

Massive stars in binary systems have long been regarded as potential sources of high-energy γ rays. The emission is principally thought to arise in the region where the stellar winds collide and accelerate relativistic particles which subsequently emit γ rays. On the basis of a three-dimensional distribution function of high-energy particles in the wind collision region—as obtained by a numerical hydrodynamics and particle transport model—we present the computation of the three-dimensional nonthermal photon emission for a given line of sight. Anisotropic inverse Compton emission is modeled using the target radiation field of both stars. Photons from relativistic bremsstrahlung and neutral pion decay are computed on the basis of local wind plasma densities. We also consider photon-photon opacity effects due to the dense radiation fields of the stars. Results are shown for different stellar separations of a given binary system comprising of a B star and a Wolf-Rayet star. The influence of orbital orientation with respect to the line of sight is also studied by using different orbital viewing angles. For the chosen electron-proton injection ratio of 10{sup –2}, we present the ensuing photon emission in terms of two-dimensional projections maps, spectral energy distributions, and integrated photon flux values in various energy bands. Here, we find a transition from hadron-dominated to lepton-dominated high-energy emission with increasing stellar separations. In addition, we confirm findings from previous analytic modeling that the spectral energy distribution varies significantly with orbital orientation.

Estimation of line dimensions in 3D direct laser writing lithography

International Nuclear Information System (INIS)

Guney, M G; Fedder, G K

2016-01-01

Two photon polymerization (TPP) based 3D direct laser writing (3D-DLW) finds application in a wide range of research areas ranging from photonic and mechanical metamaterials to micro-devices. Most common structures are either single lines or formed by a set of interconnected lines as in the case of crystals. In order to increase the fidelity of these structures and reach the ultimate resolution, the laser power and scan speed used in the writing process should be chosen carefully. However, the optimization of these writing parameters is an iterative and time consuming process in the absence of a model for the estimation of line dimensions. To this end, we report a semi-empirical analytic model through simulations and fitting, and demonstrate that it can be used for estimating the line dimensions mostly within one standard deviation of the average values over a wide range of laser power and scan speed combinations. The model delimits the trend in onset of micro-explosions in the photoresist due to over-exposure and of low degree of conversion due to under-exposure. The model guides setting of high-fidelity and robust writing parameters of a photonic crystal structure without iteration and in close agreement with the estimated line dimensions. The proposed methodology is generalizable by adapting the model coefficients to any 3D-DLW setup and corresponding photoresist as a means to estimate the line dimensions for tuning the writing parameters. (paper)

Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

Energy Technology Data Exchange (ETDEWEB)

Engel, Robin, E-mail: robin.engel@uni-oldenburg.de [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany); Düsterer, Stefan; Brenner, Günter [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Teubner, Ulrich [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany)

2016-01-01

Considering the second-order spectral correlation function of SASE-FEL radiation allows a real-time observation of the photon pulse duration during spectra acquisition. For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded.

Reflections on hard X-ray photon-in/photon-out spectroscopy for electronic structure studies

Energy Technology Data Exchange (ETDEWEB)

Glatzel, Pieter, E-mail: glatzel@esrf.fr [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France); Weng, Tsu-Chien; Kvashnina, Kristina; Swarbrick, Janine; Sikora, Marcin [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France); Gallo, Erik [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France); Department of Inorganic, Physical and Materials Chemistry, INSTM Reference Center and NIS Centre of Excellence, Università di Torino, Via P. Giuria 7, I-10125 Torino (Italy); Smolentsev, Nikolay [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France); Research Center for Nanoscale Structure of Matter, Southern Federal University, str. Zorge 5, 344090 Rostov-on-Don (Russian Federation); Mori, Roberto Alonso [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France)

2013-06-15

Highlights: ► Overview of some recent developments in hard X-ray RXES/RIXS. ► Evaluation of spectral line broadening in RXES/RIXS. ► Modelling of RXES/RIXS by ground state DFT calculations. ► Discussion on when HERFD provides a good approximation to XAS. -- Abstract: An increasing community of researchers in various fields of natural sciences is combining X-ray absorption with X-ray emission spectroscopy (XAS–XES) to study electronic structure. With the applications becoming more diverse, the objectives and the requirements in photon-in/photon-out spectroscopy are becoming broader. It is desirable to find simple experimental protocols, robust data reduction and theoretical tools that help the experimentalist to understand their data and learn about the electronic structure. This article presents a collection of considerations on non-resonant and resonant XES with the aim to guide the experimentalist to make good use of this technique.

Reprocessing of Soft X-ray Emission Lines in Black Hole Accretion Disks

International Nuclear Information System (INIS)

Mauche, C W; Liedahl, D A; Mathiesen, B F; Jimenez-Garate, M A; Raymond, J C

2003-01-01

By means of a Monte Carlo code that accounts for Compton scattering and photoabsorption followed by recombination, we have investigated the radiation transfer of Lyα, Heα, and recombination continua photons of H- and He-like C, N, O, and Ne produced in the photoionized atmosphere of a relativistic black hole accretion disk. We find that photoelectric opacity causes significant attenuation of photons with energies above the O VIII K-edge; that the conversion efficiencies of these photons into lower-energy lines and recombination continua are high; and that accounting for this reprocessing significantly (by factors of 21% to 105%) increases the flux of the Lyα and Heα emission lines of H- and He-like C and O escaping the disk atmosphere

An Energy-Stabilized Varied-Line-Space-Monochromator Undulator Beam Line for PEEM Illumination and Magnetic Circular Dichroism

International Nuclear Information System (INIS)

Warwick, Tony; McKinney, Wayne; Domning, Ed; Doran, Andrew; Padmore, Howard

2006-01-01

A new undulator beam line has been built and commissioned at the Advanced Light Source for illumination of the PEEM3 microscope. The beam line delivers high flux beams over an energy range from C1s through the transition metals to include the M edges of the magnetic rare earth elements. We present details of the optical design, and data on the performance of the zero-order tracking of the photon energy

THz/Infrared Double Resonance Two-Photon Spectroscopy of HD+ for Determination of Fundamental Constants

Directory of Open Access Journals (Sweden)

Florin Lucian Constantin

2017-10-01

Full Text Available A double resonance two-photon spectroscopy scheme is discussed to probe jointly rotational and rovibrational transitions of ensembles of trapped HD+ ions. The two-photon transition rates and lightshifts are calculated with the two-photon tensor operator formalism. The rotational lines may be observed with sub-Doppler linewidth at the hertz level and good signal-to-noise ratio, improving the resolution in HD+ spectroscopy beyond the 10−12 level. The experimental accuracy, estimated at the 10−12 level, is comparable with the accuracy of theoretical calculations of HD+ energy levels. An adjustment of selected rotational and rovibrational HD+ lines may add clues to the proton radius puzzle, may provide an independent determination of the Rydberg constant, and may improve the values of proton-to-electron and deuteron-to-proton mass ratios beyond the 10−11 level.

Photonic Crystals Towards Nanoscale Photonic Devices

CERN Document Server

Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

2008-01-01

Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

Photonic Crystals Towards Nanoscale Photonic Devices

CERN Document Server

Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

2005-01-01

Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

On-Demand Microwave Generator of Shaped Single Photons

Science.gov (United States)

Forn-Díaz, P.; Warren, C. W.; Chang, C. W. S.; Vadiraj, A. M.; Wilson, C. M.

2017-11-01

We demonstrate the full functionality of a circuit that generates single microwave photons on demand, with a wave packet that can be modulated with a near-arbitrary shape. We achieve such a high tunability by coupling a superconducting qubit near the end of a semi-infinite transmission line. A dc superconducting quantum interference device shunts the line to ground and is employed to modify the spatial dependence of the electromagnetic mode structure in the transmission line. This control allows us to couple and decouple the qubit from the line, shaping its emission rate on fast time scales. Our decoupling scheme is applicable to all types of superconducting qubits and other solid-state systems and can be generalized to multiple qubits as well as to resonators.

Effective photons in weakly absorptive dielectric media and the Beer–Lambert–Bouguer law

International Nuclear Information System (INIS)

Judge, A C; Brownless, J S; Martijn de Sterke, C; Bhat, N A R; Sipe, J E; Steel, M J

2014-01-01

We derive effective photon modes that facilitate an intuitive and convenient picture of photon dynamics in a structured Kramers–Kronig dielectric in the limit of weak absorption. Each mode is associated with a mode field distribution that includes the effects of both material and structural dispersion, and an effective line-width that determines the temporal decay rate of the photon. These results are then applied to obtain an expression for the Beer–Lambert–Bouguer law absorption coefficient for unidirectional propagation in structured media consisting of dispersive, weakly absorptive dielectric materials

[Effects of allitridum on rapidly delayed rectifier potassium current in HEK293 cell line].

Science.gov (United States)

Zhang, Jiancheng; Lin, Kun; Wei, Zhixiong; Chen, Qian; Liu, Li; Zhao, Xiaojing; Zhao, Ying; Xu, Bin; Chen, Xi; Li, Yang

2015-08-01

To study the effect of allitridum on rapidly delayed rectifier potassium current (IKr) in HEK293 cell line. HEK293 cells were transiently transfected with HERG channel cDNA plasmid pcDNA3.1 via Lipofectamine. Allitridum was added to the extracellular solution by partial perfusion after giga seal at the final concentration of 30 µmol/L. Whole-cell patch clamp technique was used to record the HERG currents and gating kinetics before and after allitridum exposure at room temperature. The amplitude and density of IHERG were both suppressed by allitridum in a voltage-dependent manner. In the presence of allitridum, the peak current of IHERG was reduced from 73.5∓4.3 pA/pF to 42.1∓3.6 pA/pF at the test potential of +50 mV (P<0.01). Allitridum also concentration-dependently decreased the density of the IHERG. The IC50 of allitridum was 34.74 µmol/L with a Hill coefficient of 1.01. Allitridum at 30 µmol/L caused a significant positive shift of the steady-state activation curve of IHERG and a markedly negative shift of the steady-state inactivation of IHERG, and significantly shortened the slow time constants of IHERG deactivation. Allitridum can potently block IHERG in HEK293 cells, which might be the electrophysiological basis for its anti-arrhythmic action.

Mittag-Leffler Stability Theorem for Fractional Nonlinear Systems with Delay

Directory of Open Access Journals (Sweden)

S. J. Sadati

2010-01-01

Full Text Available Fractional calculus started to play an important role for analysis of the evolution of the nonlinear dynamical systems which are important in various branches of science and engineering. In this line of taught in this paper we studied the stability of fractional order nonlinear time-delay systems for Caputo's derivative, and we proved two theorems for Mittag-Leffler stability of the fractional nonlinear time delay systems.

Delayed neutrons in liquid metal spallation targets

International Nuclear Information System (INIS)

Ridikas, D.; Bokov, P.; David, J.C.; Dore, D.; Giacri, M.L.; Van Lauwe, A.; Plukiene, R.; Plukis, A.; Ignatiev, S.; Pankratov, D.

2003-01-01

The next generation spallation neutron sources, neutrino factories or RIB production facilities currently being designed and constructed around the world will increase the average proton beam power on target by a few orders of magnitude. Increased proton beam power results in target thermal hydraulic issues leading to new target designs, very often based on flowing liquid metal targets such as Hg, Pb, Pb-Bi. Radioactive nuclides produced in liquid metal targets are transported into hot cells, past electronics, into pumps with radiation sensitive components, etc. Besides the considerable amount of photon activity in the irradiated liquid metal, a significant amount of the delayed neutron precursor activity can be accumulated in the target fluid. The transit time from the front of a liquid metal target into areas, where delayed neutrons may be important, can be as short as a few seconds, well within one half-life of many delayed neutron precursors. Therefore, it is necessary to evaluate the total neutron flux (including delayed neutrons) as a function of time and determine if delayed neutrons contribute significantly to the dose rate. In this study the multi-particle transport code MCNPX combined with the material evolution program CINDER'90 will be used to evaluate the delayed neutron flux and spectra. The following scientific issues will be addressed in this paper: - Modeling of a typical geometry of the liquid metal spallation target; - Predictions of the prompt neutron fluxes, fission fragment and spallation product distributions; - Comparison of the above parameters with existing experimental data; - Time-dependent calculations of delayed neutron precursors; - Neutron flux estimates due to the prompt and delayed neutron emission; - Proposal of an experimental program to measure delayed neutron spectra from high energy spallation-fission reactions. The results of this study should be directly applicable in the design study of the European MegaPie (1 MW

Integration of Single-Photon Sources and Detectors on GaAs

Directory of Open Access Journals (Sweden)

Giulia Enrica Digeronimo

2016-10-01

Full Text Available Quantum photonic integrated circuits (QPICs on a GaAs platform allow the generation, manipulation, routing, and detection of non-classical states of light, which could pave the way for quantum information processing based on photons. In this article, the prototype of a multi-functional QPIC is presented together with our recent achievements in terms of nanofabrication and integration of each component of the circuit. Photons are generated by excited InAs quantum dots (QDs and routed through ridge waveguides towards photonic crystal cavities acting as filters. The filters with a transmission of 20% and free spectral range ≥66 nm are able to select a single excitonic line out of the complex emission spectra of the QDs. The QD luminescence can be measured by on-chip superconducting single photon detectors made of niobium nitride (NbN nanowires patterned on top of a suspended nanobeam, reaching a device quantum efficiency up to 28%. Moreover, two electrically independent detectors are integrated on top of the same nanobeam, resulting in a very compact autocorrelator for on-chip g(2(τ measurements.

Thermal problems on high flux beam lines

International Nuclear Information System (INIS)

Avery, R.T.

1983-09-01

Wiggler and undulator magnets can provide very intense photon flux densities to beam line components. This paper addresses some thermal/materials consequences due to such impingement. The LBL/Exxon/SSRL hybrid-wiggler Beam Line VI now nearing operation will be able to provide up to approx. 7 kW of total photon power at planned SPEAR operating conditions. The first masks are located at 6.5 meters from the source and may receive a peak power density (transverse to the beam) exceeding 20 kW/cm 2 . Significantly, this heat transfer rate exceeds that radiated from the sun's surface (7 kW/cm 2 ) and is comparable to that of welding torches. Clearing, cooling and configuration are of critical importance. Configurations for the first fixed mask, the movable mask, and the pivot mask on this beam line are presented together with considerations of thermal stress fatigue and of heat transfer by conduction to water-cooling circuits. Some preliminary information on heating of crystals and mirrors is also presented

Mode Selection Rule for Three-Delay Systems

Science.gov (United States)

Takahashi, Kin'ya; Kobayashi, Taizo

2017-12-01

We study the mode selection rule for a three-delay system to determine which oscillation mode is first excited by the Hopf bifurcation with increasing control parameter. We use linear stability analysis to detect an oscillating mode excited by the first bifurcation. There are two conditions, relevant and irrelevant conditions, determined by the ratios of three delay times, t1, t2, and tf, where tf is fixed and t1 and t2 are set as 0 < t1 < tf and 0 < t2 < tf. In a neighborhood of the relevant condition defined such that both t1/tf = n1/m1 and t2/tf = n2/m2 are ratios of odd to odd, oscillations nearly equal to the \\tilde{m}th-harmonic mode are excited, where \\tilde{m} is the least common multiple of m1 and m2. In the parameter space (t1,t2), there are irrelevant lines each of which is determined by a rational dependence of t1, t2, and tf, and does not allow any relevant condition. Extremely high order modes are observed along both sides of the irrelevant line. In particular, the line t2 = tf - t1, i.e., a diagonal with a slope of -1, shows the strongest irrelevancy.

Bell-state generation on remote superconducting qubits with dark photons

Science.gov (United States)

Hua, Ming; Tao, Ming-Jie; Alsaedi, Ahmed; Hayat, Tasawar; Wei, Hai-Rui; Deng, Fu-Guo

2018-06-01

We present a scheme to generate the Bell state deterministically on remote transmon qubits coupled to different 1D superconducting resonators connected by a long superconducting transmission line. Using the coherent evolution of the entire system in the all-resonance regime, the transmission line need not to be populated with microwave photons which can robust against the long transmission line loss. This lets the scheme more applicable to the distributed quantum computing on superconducting quantum circuit. Besides, the influence from the small anharmonicity of the energy levels of the transmon qubits can be ignored safely.

Radiosensitivity of mesothelioma cell lines

International Nuclear Information System (INIS)

Haekkinen, A.M.; Laasonen, A.; Linnainmaa, K.; Mattson, K.; Pyrhoenen, S.

1996-01-01

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters α and β of the linear quadratic model (LQ-model) and mean inactivation dose (D MID ) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean α value was 0.26 (range 0.48-0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: Less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The α/β ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h. (orig.)

Radiosensitivity of mesothelioma cell lines

Energy Technology Data Exchange (ETDEWEB)

Haekkinen, A.M. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland); Laasonen, A. [Dept. of Pathology, Central Hospital of Etelae-Pohjanmaa, Seinaejoki (Finland); Linnainmaa, K. [Dept. of Industrial Hygiene and Toxicology, Inst. of Occupational Health, Helsinki (Finland); Mattson, K. [Dept. Pulmonary Medicine, Univ. Central Hospital, Helsinki (Finland); Pyrhoenen, S. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland)

1996-10-01

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters {alpha} and {beta} of the linear quadratic model (LQ-model) and mean inactivation dose (D{sub MID}) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean {alpha} value was 0.26 (range 0.48-0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: Less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The {alpha}/{beta} ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h. (orig.).

Control of spontaneous emission from a microwave-field-driven four-level atom in an anisotropic photonic crystal

Science.gov (United States)

Zhang, Duo; Li, Jiahua; Ding, Chunling; Yang, Xiaoxue

2012-05-01

The spontaneous emission properties of a microwave-field-driven four-level atom embedded in anisotropic double-band photonic crystals (PCs) are investigated. We discuss the influences of the band-edge positions, Rabi frequency and detuning of the microwave field on the emission spectrum. It is found that several interesting features such as spectral-line enhancement, spectral-line suppression, spectral-line overlap, and multi-peak structures can be observed in the spectra. The proposed scheme can be achieved by use of a microwave-coupled field into hyperfine levels in rubidium atom confined in a photonic crystal. These theoretical investigations may provide more degrees of freedom to manipulate the atomic spontaneous emission.

Photonics

CERN Document Server

Andrews, David L

2015-01-01

Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

Semi-continuous on-line uranium ore analyzer

International Nuclear Information System (INIS)

Campbell, P.; Gurdy, E.M.; Hatchowski, L.

1984-01-01

The efficient process control of a uranium mill and its associated mining operation requires a nearly continuous knowledge of the uranium concentration in the ore. Generally, the approach is to use laboratory assays of grab samples from the mill feed belt. In some cases, elaborate and expensive systems have been used to ensure random sampling, but even with these systems, mass-balance discrepancies still exist. There is a requirement for an on-line instrument that can give a prompt, accurate analysis of a large portion of the feed stock. The authors have recently evaluated a laboratory system that achieves these goals using neutron activation and delayed neutron counting. The development of the on-line uranium ore analyzer is a consequence of previous work done at the Whiteshell Nuclear Research Establishment (WNRE) (Campbell et al., 1978 and 1981), and is based on the emission of delayed neutrons after the neutron irradiation of fissionable materials. The mechanism of delayed neutron emission has been described (Keepin, 1965), but briefly is as follows. The fission fragments resulting from irradiation are in an excited state. Certain of these delayed fission products, precursors, decay to a more stable state by the emission of a delayed neutron. The delayed neutrons can be divided into six groups with effective half-lives ranging from 0.2-55 sec. It is important to note that more than 50% of the delayed neutrons are emitted within the first 6 sec after irradiation; this has an influence on the design of the analysis instrument

The Advanced Photon Source injection timing system

International Nuclear Information System (INIS)

Lenkszus, F.R.; Laird, R.

1995-01-01

The Advanced Photon Source consists of five accelerators. The injection timing system provides the signals required to cause a bunch emitted from the electron gun to navigate through intermediate accelerators to a specific bucket (1 out of 1296) within the storage ring. Two linacs and a positron accumulator ring operate at 60Hz while a booster synchrotron ramps and injects into the storage ring at 2Hz. The distributed, modular VME/VXI-based injection timing system is controlled by two EPICS-based input/output controllers (IOCs). Over 40 VME/VXI cards have been developed to implement the system. Card types range from 352MHz VXI timing modules to VME-based fiber optic fanouts and logic translators/drivers. All timing is distributed with fiber optics. Timing references are derived directly from machine low-level rf of 9.77MHz and 352MHz. The timing references provide triggers to programmable delay generators. Three grades of timing are provided. Precision timing is derived from commercial digital delay generators, intermediate precision timing is obtained from VXI 8-channel digital delay generators which provide timing with 25ns peak-to-peak jitter, and modest precision timing is provided by the APS event system. The timing system is fully integrated into the APS EPICS-based control system

Relationships between processing delay and microbial load of broiler neck skin samples.

Science.gov (United States)

Lucianez, A; Holmes, M A; Tucker, A W

2010-01-01

The measurable microbial load on poultry carcasses during processing is determined by a number of factors including farm or origin, processing hygiene, and external temperature. This study investigated associations between carcass microbial load and progressive delays to processing. A total of 30 carcasses were delayed immediately after defeathering and before evisceration in a commercial abattoir in groups of five, and were held at ambient temperature for 1, 2, 3, 4, 6, and 8 h. Delayed carcasses were reintroduced to the processing line, and quantitative assessment of total viable count, coliforms, Staphylococcus aureus, and Pseudomonas spp. was undertaken on neck skin flap samples collected after carcass chilling and then pooled for each group. Sampling was repeated on 5 separate days, and the data were combined. Significant increases in total viable count (P = 0.001) and coliforms (P = 0.004), but not for S. aureus or Pseudomonas loads, were observed across the 8-h period of delay. In line with previous studies, there was significant variation in microbiological data according to sampling day. In conclusion, there is a significant and measurable decline in microbiological status of uneviscerated but defeathered poultry carcasses after an 8-h delay, but the variability of sampling results, reflecting the wide range of factors that impact microbial load, means that it is not possible to determine maximum or minimum acceptable periods of processing delay based on this criterion alone.

High-energy diffraction microscopy at the advanced photon source

DEFF Research Database (Denmark)

Lienert, U.; Li, S. F.; Hefferan, C. M.

2011-01-01

The status of the High Energy Diffraction Microscopy (HEDM) program at the 1-ID beam line of the Advanced Photon Source is reported. HEDM applies high energy synchrotron radiation for the grain and sub-grain scale structural and mechanical characterization of polycrystalline bulk materials in situ...

Tomography of photon-added and photon-subtracted states

NARCIS (Netherlands)

Bazrafkan, MR; Man'ko, [No Value

The purpose of this paper is to introduce symplectic and optical tomograms of photon-added and photon-subtracted quantum states. Explicit relations for the tomograms of photon-added and photon-subtracted squeezed coherent states and squeezed number states are obtained. Generating functions for the

Photonics

CERN Document Server

Andrews, David L

2015-01-01

Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

Photonics

CERN Document Server

Andrews, David L

2015-01-01

Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

Electromagnetically induced transparency and reduced speeds for single photons in a fully quantized model

International Nuclear Information System (INIS)

Purdy, Thomas; Ligare, Martin

2003-01-01

We introduce a simple model for electromagnetically induced transparency in which all fields are treated quantum mechanically. We study a system of three separated atoms at fixed positions in a one-dimensional multimode optical cavity. The first atom serves as the source for a single spontaneously emitted photon; the photon scatters from a three-level 'Λ'-configuration atom which interacts with an additional single-mode field coupling two of the atomic levels; the third atom serves as a detector of the total transmitted field. We find an analytical solution for the quantum dynamics. From the quantum amplitude describing the excitation of the detector atom we extract information that provides exact single-photon analogues to wave delays predicted by semi-classical theories. We also find complementary information in the expectation value of the electric field intensity operator

Gamma ray lines from a universal extra dimension

Energy Technology Data Exchange (ETDEWEB)

Bertone, Gianfranco; Jackson, C. B.; Shaughnessy, Gabe; Tait, Tim M.P.; Vallinotto, Alberto

2012-03-01

Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza--Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into \\gamma \\gamma, but we extend these results to include \\gamma Z and \\gamma H final states. We find that these spectral lines are subdominant compared to the predicted \\gamma \\gamma signal, but they would be important as follow-up signals in the event of the observation of the \\gamma \\gamma line, in order to distinguish the 5d UED model from other theoretical scenarios.

A self contained Linux based data acquisition system for 2D detectors with delay line readout

International Nuclear Information System (INIS)

Beltran, D.; Toledo, J.; Klora, A.C.; Ramos-Lerate, I.; Martinez, J.C.

2007-01-01

This article describes a fast and self-contained data acquisition system for 2D gas-filled detectors with delay line readout. It allows the realization of time resolved experiments in the millisecond scale. The acquisition system comprises of an industrial PC running Linux, a commercial time-to-digital converter and an in-house developed histogramming PCI card. The PC provides a mass storage for images and a graphical user interface for system monitoring and control. The histogramming card builds images with a maximum count rate of 5 MHz limited by the time-to-digital converter. Histograms are transferred to the PC at 85 MB/s. This card also includes a time frame generator, a calibration channel unit and eight digital outputs for experiment control. The control software was developed for easy integration into a beamline, including scans. The system is fully operational at the Spanish beamline BM16 at the ESRF in France, the neutron beamlines Adam and Eva at the ILL in France, the Max Plank Institute in Stuttgart in Germany, the University of Copenhagen in Denmark and at the future ALBA synchrotron in Spain. Some representative collected images from synchrotron and neutron beamlines are presented

An In-Line Photonic Biosensor for Monitoring of Glucose Concentrations

Directory of Open Access Journals (Sweden)

Ala'aldeen Al-Halhouli

2014-08-01

Full Text Available This paper presents two PDMS photonic biosensor designs that can be used for continuous monitoring of glucose concentrations. The first design, the internally immobilized sensor, consists of a reactor chamber, micro-lenses and self-alignment structures for fiber optics positioning. This sensor design allows optical detection of glucose concentrations under continuous glucose flow conditions of 33 µL/h based on internal co-immobilization of glucose oxidase (GOX and horseradish peroxidase (HRP on the internal PDMS surface of the reactor chamber. For this design, two co-immobilization methods, the simple adsorption and the covalent binding (PEG methods were tested. Experiments showed successful results when using the covalent binding (PEG method, where glucose concentrations up to 5 mM with a coefficient of determination (R2 of 0.99 and a limit of detection of 0.26 mM are detectable. The second design is a modified version of the internally immobilized sensor, where a microbead chamber and a beads filling channel are integrated into the sensor. This modification enabled external co-immobilization of enzymes covalently onto functionalized silica microbeads and allows binding a huge amount of HRP and GOX enzymes on the microbeads surfaces which increases the interaction area between immobilized enzymes and the analyte. This has a positive effect on the amount and rate of chemical reactions taking place inside the chamber. The sensor was tested under continuous glucose flow conditions and was found to be able to detect glucose concentrations up to 10 mM with R2 of 0.98 and a limit of detection of 0.7 mM. Such results are very promising for the application in photonic LOC systems used for online analysis.

Heavy quark pair production in polarized photon-photon collisions

International Nuclear Information System (INIS)

Jikia, G.; Tkabladze, A.

2000-04-01

We present the cross sections of the heavy quark-antiquark pair production in polarized photon photon collision for the general case of photon polarizations. The numerical results for top-antitop production cross sections together with production asymmetries are obtained for linearly polarized photon-photon collisions, including QCD radiative corrections. (orig.)

Neutron interrogation of actinides with a 17 MeV electron accelerator and first results from photon and neutron interrogation non-simultaneous measurements combination

Energy Technology Data Exchange (ETDEWEB)

Sari, A., E-mail: adrien.sari@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Carrel, F.; Lainé, F. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Lyoussi, A. [CEA, DEN, 13108 Saint-Paul-Lez-Durance Cedex (France)

2013-10-01

In this article, we demonstrate the feasibility of neutron interrogation using the conversion target of a 17 MeV linear electron accelerator as a neutron generator. Signals from prompt neutrons, delayed neutrons, and delayed gamma-rays, emitted by both uranium and plutonium samples were analyzed. First results from photon and neutron interrogation non-simultaneous measurements combination are also reported in this paper. Feasibility of this technique is shown in the frame of the measurement of uranium enrichment. The latter was carried out by combining detection of prompt neutrons from thermal fission and delayed neutrons from photofission, and by combining delayed gamma-rays from thermal fission and delayed gamma-rays from photofission.

Photon-photon collisions and photon structure functions at LEP

CERN Document Server

Patt, J

2000-01-01

The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers recent results on QED structure functions and on the hadronic structure function F/sub 2//sup gamma /. (13 refs).

CMOS-compatible photonic devices for single-photon generation

Directory of Open Access Journals (Sweden)

Xiong Chunle

2016-09-01

Full Text Available Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal–oxide–semiconductor (CMOS-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

Enhancing the detection of edges and non-differentiable points in an NMR spectrum using delayed-acquisition

Science.gov (United States)

Gong, Zhaoyuan; Walls, Jamie D.

2018-02-01

Delayed-acquisition, which is a common technique for improving spectral resolution in Fourier transform based spectroscopies, typically relies upon differences in T2 relaxation rates that are often due to underlying differences in dynamics and/or complexities of the spin systems being studied. After an acquisition delay, the broad signals from fast T2 -relaxing species are more suppressed relative to the sharp signals from slow T2 -relaxing species. In this paper, an alternative source of differential "dephasing" under delayed-acquisition is demonstrated that is based solely upon the mathematical properties of the line shape and is independent of the underlying spin dynamics and/or complexity. Signals associated with frequencies where the line shape either changes sharply and/or is non-differentiable at some finite order dephase at a much slower rate than those signals associated with frequencies where the line shape is smooth. Experiments employing delayed-acquisition to study interfaces in biphasic samples, to measure spatially-dependent longitudinal relaxation, and to highlight sharp features in NMR spectra are presented.

Photonics

CERN Document Server

Andrews, David L

2015-01-01

This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

Electrically Driven Photonic Crystal Nanocavity Devices

Science.gov (United States)

2012-01-01

material, here gallium arsenide and indium arsenide self- assembled quantum dots (QDs). QDs are preferred for the gain medium because they can have...blue points ) and 150 K (green points ). The black lines are linear fits to the above threshold output power of the lasers, which are used to find the...SHAMBAT et al.: ELECTRICALLY DRIVEN PHOTONIC CRYSTAL NANOCAVITY DEVICES 1707 Fig. 13. (a) Tilted SEM picture of a fabricated triple cavity device. The in

Development and construction of the low-energy photon tagger NEPTUN

Energy Technology Data Exchange (ETDEWEB)

Lindenberg, K.

2007-07-15

Within the scope of this thesis a photon tagging system was designed and constructed at the superconducting Darmstadt electron linear accelerator (S-DALINAC). The set-up consists of a deflecting magnet, an array of focal plane detectors, the data acquisition system and new beam-line components. The system provides tagged photons in an energy range from 6 MeV to 20 MeV with the emphasis on best possible resolution and intensity. The absolute energy resolution of photons at 10 MeV is better than 25 keV. With the current focal-plane detectors a maximum rate of tagged photons of 10{sup 4}/(keV.s) can be achieved. An upgrade to more than 10{sup 5}/(keV.s) with an alternative detector array is under investigation. The design values mentioned above are the requirements for planned experiments in the fields of nuclear astrophysics and nuclear structure. The most important constraints which have to be considered arise from the special demands of ({gamma},n) reactions above but close to the particle threshold which generates slow neutrons with energies of a few hundreds of keV. The unambiguous assignment of slow neutrons to prompt electrons is done on-line in special buffered time-to-digital converters. With a design of the data acquisition for this scenario one also covers the requirements for experiments with prompt detection of the ejectiles such as in nuclear resonance fluorescence and ({gamma},n) far above the threshold. This photon tagging system enables to measure ({gamma},x) cross sections as a function of excitation energy and decay patterns after particle evaporation. It is an important extension to the high-flux activation experiments and the nuclear resonance fluorescence experiments below the threshold with untagged bremsstrahlung. (orig.)

Development and construction of the low-energy photon tagger NEPTUN

International Nuclear Information System (INIS)

Lindenberg, K.

2007-07-01

Within the scope of this thesis a photon tagging system was designed and constructed at the superconducting Darmstadt electron linear accelerator (S-DALINAC). The set-up consists of a deflecting magnet, an array of focal plane detectors, the data acquisition system and new beam-line components. The system provides tagged photons in an energy range from 6 MeV to 20 MeV with the emphasis on best possible resolution and intensity. The absolute energy resolution of photons at 10 MeV is better than 25 keV. With the current focal-plane detectors a maximum rate of tagged photons of 10 4 /(keV.s) can be achieved. An upgrade to more than 10 5 /(keV.s) with an alternative detector array is under investigation. The design values mentioned above are the requirements for planned experiments in the fields of nuclear astrophysics and nuclear structure. The most important constraints which have to be considered arise from the special demands of (γ,n) reactions above but close to the particle threshold which generates slow neutrons with energies of a few hundreds of keV. The unambiguous assignment of slow neutrons to prompt electrons is done on-line in special buffered time-to-digital converters. With a design of the data acquisition for this scenario one also covers the requirements for experiments with prompt detection of the ejectiles such as in nuclear resonance fluorescence and (γ,n) far above the threshold. This photon tagging system enables to measure (γ,x) cross sections as a function of excitation energy and decay patterns after particle evaporation. It is an important extension to the high-flux activation experiments and the nuclear resonance fluorescence experiments below the threshold with untagged bremsstrahlung. (orig.)

Two-photon double ionization of the helium atom by ultrashort pulses

International Nuclear Information System (INIS)

Palacios, Alicia; Horner, Daniel A.; Rescigno, Thomas N.; McCurdy, C. William

2010-01-01

Two-photon double ionization of the helium atom was the subject of early experiments at FLASH and will be the subject of future benchmark measurements of the associated electron angular and energy distributions. As the photon energy of a single femtosecond pulse is raised from the threshold for two-photon double ionization at 39.5 eV to beyond the sequential ionization threshold at 54.4 eV, the electron ejection dynamics change from the highly correlated motion associated with nonsequential absorption to the much less correlated sequential ionization process. The signatures of both processes have been predicted in accurate ab initio calculations of the joint angular and energy distributions of the electrons, and those predictions contain some surprises. The dominant terms that contribute to sequential ionization make their presence apparent several eV below that threshold. In two-color pump probe experiments with short pulses whose central frequencies require that the sequential ionization process necessarily dominates, a two-electron interference pattern emerges that depends on the pulse delay and the spin state of the atom.

CONCEPTS OF IMPROVING CURRENT PROTECTION OF POWER-GRID LINES

Directory of Open Access Journals (Sweden)

F. A. Romaniuk

2015-01-01

Full Text Available The  6–35  kV  power-grid  current  protection  serves  to  protect  the  transmission  lines against phase-to-phase short-circuits. The major disadvantage of it lies in the relatively large time delays of the last stages especially in the main sections of the grid owing to the stepped relay characteristics as well as a large number of the steps. A full-fledged protection of the 6–35 kV lines against inter-phase short circuits can be provided by the two-stage current protection: the first stage being the current cutoff without any time delay and the second stage – the maximum current protection where the time delay is linear contingent on the distance between the protection placement and the fault-point location. The article introduces the rating formulae for the time delays of the second-stage and their exemplary graphic presentation. The authors offer a variant for solving the problem with computation of the second-stage time delays in those instances where several feeders diverge from the bus bars of the substation located in the end of the protected line.Improving current protections for the 6–35 kV transmission lines with one-end power supply against interphase short-circuits can be based on the collective application of the following principles: accounting for the type and location of the short-circuit which provides for the high-performance cutoff zone instantaneous expansion and its independence on the mode of failure and the grid operation mode. It also allows increase of the last stage sensitiveness towards asymmetrical short-circuits; detection of the short-circuit location only on the results of fault currents measurement which simplifies the protection implementation; realization of the last (second protection stage with linear-dependent time delay which ensures potentiality of its operation speed increase.

Multi-photon absorption limits to heralded single photon sources

Science.gov (United States)

Husko, Chad A.; Clark, Alex S.; Collins, Matthew J.; De Rossi, Alfredo; Combrié, Sylvain; Lehoucq, Gaëlle; Rey, Isabella H.; Krauss, Thomas F.; Xiong, Chunle; Eggleton, Benjamin J.

2013-01-01

Single photons are of paramount importance to future quantum technologies, including quantum communication and computation. Nonlinear photonic devices using parametric processes offer a straightforward route to generating photons, however additional nonlinear processes may come into play and interfere with these sources. Here we analyse spontaneous four-wave mixing (SFWM) sources in the presence of multi-photon processes. We conduct experiments in silicon and gallium indium phosphide photonic crystal waveguides which display inherently different nonlinear absorption processes, namely two-photon (TPA) and three-photon absorption (ThPA), respectively. We develop a novel model capturing these diverse effects which is in excellent quantitative agreement with measurements of brightness, coincidence-to-accidental ratio (CAR) and second-order correlation function g(2)(0), showing that TPA imposes an intrinsic limit on heralded single photon sources. We build on these observations to devise a new metric, the quantum utility (QMU), enabling further optimisation of single photon sources. PMID:24186400

Non-Poissonian photon statistics from macroscopic photon cutting materials.

Science.gov (United States)

de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

2017-05-24

In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

Deterministically swapping frequency-bin entanglement from photon-photon to atom-photon hybrid systems

Science.gov (United States)

Ou, Bao-Quan; Liu, Chang; Sun, Yuan; Chen, Ping-Xing

2018-02-01

Inspired by the recent developments of the research on the atom-photon quantum interface and energy-time entanglement between single-photon pulses, we are motivated to study the deterministic protocol for the frequency-bin entanglement of the atom-photon hybrid system, which is analogous to the frequency-bin entanglement between single-photon pulses. We show that such entanglement arises naturally in considering the interaction between a frequency-bin entangled single-photon pulse pair and a single atom coupled to an optical cavity, via straightforward atom-photon phase gate operations. Its anticipated properties and preliminary examples of its potential application in quantum networking are also demonstrated. Moreover, we construct a specific quantum entanglement witness tool to detect such extended frequency-bin entanglement from a reasonably general set of separable states, and prove its capability theoretically. We focus on the energy-time considerations throughout the analysis.

Neuromorphic photonic networks using silicon photonic weight banks.

Science.gov (United States)

Tait, Alexander N; de Lima, Thomas Ferreira; Zhou, Ellen; Wu, Allie X; Nahmias, Mitchell A; Shastri, Bhavin J; Prucnal, Paul R

2017-08-07

Photonic systems for high-performance information processing have attracted renewed interest. Neuromorphic silicon photonics has the potential to integrate processing functions that vastly exceed the capabilities of electronics. We report first observations of a recurrent silicon photonic neural network, in which connections are configured by microring weight banks. A mathematical isomorphism between the silicon photonic circuit and a continuous neural network model is demonstrated through dynamical bifurcation analysis. Exploiting this isomorphism, a simulated 24-node silicon photonic neural network is programmed using "neural compiler" to solve a differential system emulation task. A 294-fold acceleration against a conventional benchmark is predicted. We also propose and derive power consumption analysis for modulator-class neurons that, as opposed to laser-class neurons, are compatible with silicon photonic platforms. At increased scale, Neuromorphic silicon photonics could access new regimes of ultrafast information processing for radio, control, and scientific computing.

Simulation of loss electron in vacuum magnetically insulated transmission lines

International Nuclear Information System (INIS)

Zhang Pengfei; Li Yongdong; Liu Chunliang; Wang Hongguang; Guo Fan; Yang Hailiang; Qiu Aici; Su Zhaofeng; Sun Jianfeng; Sun Jiang; Gao Yi

2011-01-01

In the beginning of magnetic insulated period, loss electron in coaxial vacuum magnetically insulated transmission line (MITL) strikes anode and the bremsstrahlung photons are generated in the mean time. Based on the self-limited flow model, velocity in direction of energy transport, energy spectrum and angular distribution of loss electron are simulated by PIC code, energy spectrum of bremsstrahlung photons as well calculated though Monte Carlo method. Computational results show that the velocity of loss electron is less than 2.998 x 108 m/s, the angular excursion of electron is not much in a board extent of energy spectrum. These results show an indirect diagnosis of vacuum insulted transmission line working status based on loss electron bremsstrahlung. (authors)

Silicon Photonics towards Disaggregation of Resources in Data Centers

Directory of Open Access Journals (Sweden)

Miltiadis Moralis-Pegios

2018-01-01

Full Text Available In this paper, we demonstrate two subsystems based on Silicon Photonics, towards meeting the network requirements imposed by disaggregation of resources in Data Centers. The first one utilizes a 4 × 4 Silicon photonics switching matrix, employing Mach Zehnder Interferometers (MZIs with Electro-Optical phase shifters, directly controlled by a high speed Field Programmable Gate Array (FPGA board for the successful implementation of a Bloom-Filter (BF-label forwarding scheme. The FPGA is responsible for extracting the BF-label from the incoming optical packets, carrying out the BF-based forwarding function, determining the appropriate switching state and generating the corresponding control signals towards conveying incoming packets to the desired output port of the matrix. The BF-label based packet forwarding scheme allows rapid reconfiguration of the optical switch, while at the same time reduces the memory requirements of the node’s lookup table. Successful operation for 10 Gb/s data packets is reported for a 1 × 4 routing layout. The second subsystem utilizes three integrated spiral waveguides, with record-high 2.6 ns/mm2, delay versus footprint efficiency, along with two Semiconductor Optical Amplifier Mach-Zehnder Interferometer (SOA-MZI wavelength converters, to construct a variable optical buffer and a Time Slot Interchange module. Error-free on-chip variable delay buffering from 6.5 ns up to 17.2 ns and successful timeslot interchanging for 10 Gb/s optical packets are presented.

Microwave background constraints on mixing of photons with hidden photons

International Nuclear Information System (INIS)

Mirizzi, Alessandro; Redondo, Javier; Sigl, Guenter

2008-12-01

Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle χ 0 -7 - 10 -5 for hidden photon masses between 10 -14 eV and 10 -7 eV. This low-mass and low-mixing region of the hidden photon parameter space was previously unconstrained. (orig.)

Plasma core electron density and temperature measurements using CVI line emissions in TCABR Tokamak

Energy Technology Data Exchange (ETDEWEB)

Nascimento, F. do, E-mail: fellypen@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Componentes Semicondutores; Machida, M. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Severo, J.H.F.; Sanada, E.; Ronchi, G. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

2015-08-15

In this work, we present results of electron temperature (T{sub e} ) and density (n {sub e} ) measurements obtained in Tokamak Chauffage Alfven Bresilien (TCABR) tokamak using visible spectroscopy from CVI line emissions which occurs mainly near the center of the plasma column. The presented method is based on a well-known relationship between the particle flux (Γ {sub ion}) and the photon flux (ø {sub ion}) emitted by an ion species combined with ionizations per photon atomic data provided by the atomic data and analysis structure (ADAS) database. In the experiment, we measured the photon fluxes of three different CVI spectral line emissions, 4685.2, 5290.5, and 6200.6 Å (one line per shot). Using this method it was possible to find out the temporal evolution of T{sub e} and n{sub e} in the plasma. The results achieved are in good agreement with T{sub e} and n{sub e} measurements made using other diagnostic tools. (author)

Photon-photon inclusive scattering and perturbative QCD

International Nuclear Information System (INIS)

Maor, U.

1988-01-01

Perturbative QCD expectations and problems associated with the study of the photon structure function data are reviewed. An assessment is given for the viability and sensitivity of photon-photon scattering as a decisive tool for the determination of the QCD scale. Particular attention is given to the theoretical problems of singularity cancellations at x = 0 and threshold-associated difficulties at x = 1 and their implications on the actual data analysis. It is concluded that the experimental results, while not providing a decisive verification of QCD at small distances, do add to other independent experiments which are all consistent with the theory and suggest a reasonably well defined QCD scale parameter. The importance of the small Q 2 limit to photon-photon analysis is discussed and the data are examined in an attempt to identify and isolate the contributions of the hadronic and point-like sectors of the target photon. 21 refs., 7 figs. (author)

Microwave background constraints on mixing of photons with hidden photons

Energy Technology Data Exchange (ETDEWEB)

Mirizzi, Alessandro [Max-Planck-Institut fuer Physik, Muenchen (Germany); Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sigl, Guenter [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

2008-12-15

Various extensions of the Standard Model predict the existence of hidden photons kinetically mixing with the ordinary photon. This mixing leads to oscillations between photons and hidden photons, analogous to the observed oscillations between different neutrino flavors. In this context, we derive new bounds on the photon-hidden photon mixing parameters using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of the Cosmic Background Explorer. Requiring the distortions of the CMB induced by the photon-hidden photon mixing to be smaller than experimental upper limits, this leads to a bound on the mixing angle {chi}{sub 0}

Intensity-modulated photon arc therapy for treatment of pleural mesothelioma

International Nuclear Information System (INIS)

Tobler, Matt; Watson, Gordon; Leavitt, Dennis

2002-01-01

Radiotherapy plays a key role in the definitive or adjuvant management of patients with mesothelioma of the pleural surface. Many patients are referred for radiation with intact lung following biopsy or subtotal pleurectomy. Delivery of efficacious doses of radiation to the pleural lining while avoiding lung parenchyma toxicity has been a difficult technical challenge. Using opposed photon fields produce doses in lung that result in moderate-to-severe pulmonary toxicity in 100% of patients treated. Combined photon-electron beam treatment, at total doses of 4250 cGy to the pleural surface, results in two-thirds of the lung volume receiving over 2100 cGy. We have developed a technique using intensity-modulated photon arc therapy (IMRT) that significantly improves the dose distribution to the pleural surface with concomitant decrease in dose to lung parenchyma compared to traditional techniques. IMRT treatment of the pleural lining consists of segments of photon arcs that can be intensity modulated with varying beam weights and multileaf positions to produce a more uniform distribution to the pleural surface, while at the same time reducing the overall dose to the lung itself. Computed tomography (CT) simulation is critical for precise identification of target volumes as well as critical normal structures (lung and heart). Rotational arc trajectories and individual leaf positions and weightings are then defined for each CT plane within the patient. This paper will describe the proposed rotational IMRT technique and, using simulated isodose distributions, show the improved potential for sparing of dose to the critical structures of the lung, heart, and spinal cord

The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

DEFF Research Database (Denmark)

Grier, C.J.; Peterson, B.M.; Pogge, R.W.

2013-01-01

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velo...

Cycles of self-pulsations in a photonic integrated circuit.

Science.gov (United States)

Karsaklian Dal Bosco, Andreas; Kanno, Kazutaka; Uchida, Atsushi; Sciamanna, Marc; Harayama, Takahisa; Yoshimura, Kazuyuki

2015-12-01

We report experimentally on the bifurcation cascade leading to the appearance of self-pulsation in a photonic integrated circuit in which a laser diode is subjected to delayed optical feedback. We study the evolution of the self-pulsing frequency with the increase of both the feedback strength and the injection current. Experimental observations show good qualitative accordance with numerical results carried out with the Lang-Kobayashi rate equation model. We explain the mechanism underlying the self-pulsations by a phenomenon of beating between successive pairs of external cavity modes and antimodes.

Room-temperature-deposited dielectrics and superconductors for integrated photonics.

Science.gov (United States)

Shainline, Jeffrey M; Buckley, Sonia M; Nader, Nima; Gentry, Cale M; Cossel, Kevin C; Cleary, Justin W; Popović, Miloš; Newbury, Nathan R; Nam, Sae Woo; Mirin, Richard P

2017-05-01

We present an approach to fabrication and packaging of integrated photonic devices that utilizes waveguide and detector layers deposited at near-ambient temperature. All lithography is performed with a 365 nm i-line stepper, facilitating low cost and high scalability. We have shown low-loss SiN waveguides, high-Q ring resonators, critically coupled ring resonators, 50/50 beam splitters, Mach-Zehnder interferometers (MZIs) and a process-agnostic fiber packaging scheme. We have further explored the utility of this process for applications in nonlinear optics and quantum photonics. We demonstrate spectral tailoring and octave-spanning supercontinuum generation as well as the integration of superconducting nanowire single photon detectors with MZIs and channel-dropping filters. The packaging approach is suitable for operation up to 160 °C as well as below 1 K. The process is well suited for augmentation of existing foundry capabilities or as a stand-alone process.

Neutron and photon dose assessment in Indus accelerator complex

International Nuclear Information System (INIS)

Verma, Dimple; Haridas Nair, G.; Bandopadhyay, Tapas; Tripathy, R.M.; Pal, Rupali; Bakshi, A.K.; Palani Selvam, T.; Datta, D.

2016-02-01

Indus Accelerator Complex (IAC) consists of 20 MeV Microtron, 450/550 MeV Booster, 450 MeV Indus-1 and 2.5 GeV Indus-2 storage rings. The radiation environment in Indus Accelerator Complex comprises of bremsstrahlung photons, electrons, positrons, photo neutrons and muons, out of which, bremsstrahlung photons are the major constituent of the prompt radiation. Major problem faced for on-line detection of neutrons is their severely pulsed nature. In the present study, measurement of neutron and photon dose rates in Indus Accelerator Complex was carried out using passive dosimeters such as CR-39 solid state nuclear track detector (SSNTD) and CaSO 4 :Dy Teflon disc, 6 LiF:Mg,Ti (TLD 600) and 7 LiF:Mg,Ti (TLD 700) based thermo luminescent (TL) detectors. The report describes the details of the measurement and discusses the results. (author)

Radiation response of mouse lymphoid and myeloid cell lines. Pt. 3

International Nuclear Information System (INIS)

Radford, I.R.; Murphy, T.K.

1994-01-01

The authors have examined the timing of γ-irradiation-induced death in relation to cell cycle progression using a panel of mouse lymphoid or myeloid cell lines. Death was found to occur immediately after irradiation ('rapid interphase' death), or after arrest in G 2 phase ('delayed interphase' death), or following one or more mitoses ('mitotic/delayed mitotic' death). In part II of this series of papers the authors demonstrated the occurrence of radiation-induced apoptosis in all these cell lines. Several of the cell lines showed different timing of death dependent upon the radiation dose used. These differences in the timing of radiation-induced death are shown to be useful indicators of the relative radiosensitivity of haematopoietic cell lines. (author)

Frequency splitter based on the directional emission from surface modes in dielectric photonic crystal structures.

Science.gov (United States)

Tasolamprou, Anna C; Zhang, Lei; Kafesaki, Maria; Koschny, Thomas; Soukoulis, Costas M

2015-06-01

We demonstrate the numerical design and the experimental validation of frequency dependent directional emission from a dielectric photonic crystal structure. The wave propagates through a photonic crystal line-defect waveguide, while a surface layer at the termination of the photonic crystal enables the excitation of surface modes and a subsequent grating layer transforms the surface energy into outgoing propagating waves of the form of a directional beam. The angle of the beam is controlled by the frequency and the structure operates as a frequency splitter in the intermediate and far field region.

Fabrication of Three Dimensional Cu Metallic Photonic Crystal by Electroless Plating

International Nuclear Information System (INIS)

Wu, S-C; Hou, F-J; Jian, P-C Jang-; Tsai, M-S; Chen, M-C; Li, L-S; Huang, J-Y; Lin, S-Y

2007-01-01

A 3D copper (Cu) metallic photonic crystal (MPC) with 180nm line width was fabricated by electroless plating. The mold of 3D MPC for Cu replacement is poly-Si. It has been verified as an enhancing thermal photovoltaic effect while the mold was transferred into tungsten MPC by chemical vapor deposition method. The 5 layers structure of Cu MPC was clear observed with scanning electron microscopy. The photonic band-gap ranged from 1.5 to 13 μm was measured by Fourier transform infrared spectroscopy (FTIR) instrument

Dicke coherent narrowing in two-photon and Raman spectroscopy of thin vapor cells

International Nuclear Information System (INIS)

Dutier, Gabriel; Todorov, Petko; Hamdi, Ismahene; Maurin, Isabelle; Saltiel, Solomon; Bloch, Daniel; Ducloy, Martial

2005-01-01

The principle of coherent Dicke narrowing in a thin vapor cell, in which sub-Doppler spectral line shapes are observed under a normal irradiation for a λ/2 thickness, is generalized to two-photon spectroscopy. Only the sum of the two wave vectors must be normal to the cell, making the two-photon scheme highly versatile. A comparison is provided between the Dicke narrowing with copropagating fields, and the residual Doppler broadening occurring with counterpropagating geometries. The experimental feasibility is discussed on the basis of a first observation of a two-photon resonance in a 300-nm-thick Cs cell. Extension to the Raman situation is finally considered

X-Ray Lines from Dark Matter Annihilation at the keV Scale.

Science.gov (United States)

Brdar, Vedran; Kopp, Joachim; Liu, Jia; Wang, Xiao-Ping

2018-02-09

In 2014, several groups reported hints for a yet unidentified line in astrophysical x-ray signals from galaxies and galaxy clusters at an energy of 3.5 keV. While it is not unlikely that this line is simply a reflection of imperfectly modeled atomic transitions, it has renewed the community's interest in models of keV-scale dark matter, whose decay would lead to such a line. The alternative possibility of dark matter annihilation into monochromatic photons is far less explored, a lapse that we strive to amend in this Letter. More precisely, we introduce a novel model of fermionic dark matter χ with O(keV) mass, annihilating to a scalar state ϕ which in turn decays to photons, for instance via loops of heavy vectorlike fermions. The resulting photon spectrum is box shaped, but if χ and ϕ are nearly degenerate in mass, it can also resemble a narrow line. We discuss dark matter production via two different mechanisms-misalignment and freeze-in-which both turn out to be viable in vast regions of parameter space. We constrain the model using astrophysical x-ray data, and we demonstrate that, thanks to the velocity dependence of the annihilation cross section, it has the potential to reconcile the various observations of the 3.5 keV line. We finally argue that the model can easily avoid structure formation constraints on keV-scale dark matter.

Delayed coherent quantum feedback from a scattering theory and a matrix product state perspective

Science.gov (United States)

Guimond, P.-O.; Pletyukhov, M.; Pichler, H.; Zoller, P.

2017-12-01

We study the scattering of photons propagating in a semi-infinite waveguide terminated by a mirror and interacting with a quantum emitter. This paradigm constitutes an example of coherent quantum feedback, where light emitted towards the mirror gets redirected back to the emitter. We derive an analytical solution for the scattering of two-photon states, which is based on an exact resummation of the perturbative expansion of the scattering matrix, in a regime where the time delay of the coherent feedback is comparable to the timescale of the quantum emitter’s dynamics. We compare the results with numerical simulations based on matrix product state techniques simulating the full dynamics of the system, and extend the study to the scattering of coherent states beyond the low-power limit.

Measurement of isolated photon production in deep-inelastic scattering at HERA

International Nuclear Information System (INIS)

Aaron, F.D.; Alexa, C.

2007-10-01

The production of isolated photons in deep-inelastic scattering ep → eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4 2 2 and a mass of the hadronic system W X >50 GeV. The analysis is based on a total integrated luminosity of 227 pb -1 . The production cross section of isolated photons with a transverse energy in the range 3 γ T γ γ T , η γ and Q 2 . Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections. (orig.)

Measurement of isolated photon production in deep-inelastic scattering at HERA

Science.gov (United States)

Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2008-04-01

The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 450 GeV. The analysis is based on a total integrated luminosity of 227 pb-1. The production cross section of isolated photons with a transverse energy in the range 3photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.

On the validity of the equivalent-photon approximation for virtual photon-photon collisions

International Nuclear Information System (INIS)

Carimalo, C.; Kessler, P.; Parisi, J.

1979-05-01

For virtual photon-photon collisions in electron storage rings, one derive the equivalent-photon approximation from a helicity treatment, and present it in two forms, involving respectively (i) polarized transverse photons ('transverse-photon approximation') and (ii) unpolarized ones ('Williams-Weizsaecker approximation'). One first postulates the conditions of validity of the approximation on the basis of analytic considerations, and then check them numerically in the case of the process e e → e e μ + μ - . For this check, we consider the completely differentiated cross section as far as approximation (i) is concerned; and in the case of approximation (ii), the cross section differentiated with respect to all variables except the azimuthal angles. The results are given in the form of Tables showing the lower and higher limit of the error involved in the approximation for a large variety of kinematic configurations (i. e., energy losses and scattering angles of both electrons). Those Tables are discussed in detail, and conclusions are drawn as to the applicability of the equivalent-photon approximation to future experiments to be performed with high-energy electron storage rings

Photon Counting Using Edge-Detection Algorithm

Science.gov (United States)

Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

2010-01-01

-bit comparator, which digitizes the input referenced to an adjustable threshold value. This results in four independent serial sample streams of binary 1s and 0s, which are ORed together at rates up to 10 GHz. This single serial stream is then deserialized by a factor of 16 to create 16 signal lines at a rate of 622.5 MHz or lower for input to a high-speed digital processor assembly. The new design and corresponding hardware can be employed with a quad-photon counting detector capable of handling photon rates on the order of multi-gigaphotons per second, whereas prior art was only capable of handling a single input at 1/4 the flux rate. Additionally, the hardware edge-detection algorithm has provided the ability to process 3-10 higher photon flux rates than previously possible by removing the limitation that photoncounting detector output pulses on multiple channels being ORed not overlap. Now, only the leading edges of the pulses are required to not overlap. This new photon counting digitizer hardware architecture supports a universal front end for an optical communications receiver operating at data rates from kilobits to over one gigabit per second to meet increased mission data volume requirements.

Photon-Photon Luminosities in Relativistic Heavy Ion Collisions at LHC Energies

OpenAIRE

Hencken, Kai; Trautmann, Dirk; Baur, Gerhard

1994-01-01

Effective photon-photon luminosities are calculated for various realistic hadron collider scenarios. The main characteristics of photon-photon processes at relativistic heavy-ion colliders are established and compared to the corresponding photon-photon luminosities at electron-positron and future Photon Linear Colliders (PLC). Higher order corrections as well as inelastic processes are discussed. It is concluded that feasible high luminosity Ca-Ca collisions at the Large Hadron Collider (LHC)...

A successful experimental observation of double-photon Compton scattering of γ rays using a single γ detector

International Nuclear Information System (INIS)

Saddi, M.B.; Sandhu, B.S.; Singh, B.

2006-01-01

The phenomenon of double-photon Compton scattering has been successfully observed using a single γ detector, a technique avoiding the use of the complicated slow-fast coincidence set-up used till now for observing this higher-order process. Here doubly differential collision cross-sections integrated over the directions of one of the two final photons, the direction of other one being kept fixed, are measured experimentally for 0.662 MeV incident γ photons. The energy spectra of the detected photons are observed as a long tail to the single-photon Compton line on the lower side of the full energy peak in the recorded scattered energy spectrum. The present results are in agreement with theory of this process

Generation of polarization-entangled photon pairs in a cascade of two type-I crystals pumped by femtosecond pulses

International Nuclear Information System (INIS)

Nambu, Yoshihiro; Usami, Koji; Tsuda, Yoshiyuki; Matsumoto, Keiji; Nakamura, Kazuo

2002-01-01

We report the generation of polarization-entangled photons by femtosecond-pulse-pumped spontaneous parametric down-conversion in a cascade of two type-I crystals. Highly entangled pulsed states were obtained by introducing a temporal delay between the two orthogonal polarization components of the pump field. They exhibited high-visibility quantum interference and a large concurrence value, without the need of postselection using narrow-bandwidth spectral filters. The results are well explained by the theory which incorporates the space-time dependence of interfering two-photon amplitudes if dispersion and birefringence in the crystals are appropriately taken into account. Such a pulsed entangled photon well localized in time domain is useful for various quantum communication experiments, such as quantum cryptography and quantum teleportation

Study of Compton broadening due to electron-photon scattering

Directory of Open Access Journals (Sweden)

Srinivasa Rao M.

2010-01-01

Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radia­tion field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation. The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons. It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle. We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

Study of Compton Broadening Due to Electron-Photon Scattering

Directory of Open Access Journals (Sweden)

Srinivasa Rao, M.

2010-06-01

Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

Radiation cell survival and growth delay studies in multicellular spheroids of small-cell lung carcinoma

International Nuclear Information System (INIS)

Duchesne, G.M.; Peacock, J.H.

1987-01-01

The radiation sensitivity of two small-cell lung carcinoma cell lines growing as multicellular spheroids in static culture was determined using clonogenic cell survival and growth delay as endpoints. Growth delay determination suggested that clonogenic cell kill was less than was obtained by direct assay of cell survival. Recovery from potentially lethal damage was assayed in one line (HC12) but was not demonstrable, and clonogenic cell survival decreased with time in treated spheroids with diameters greater than 300 μm which contained a hypoxic cell population. Microscopic examination of the treated spheroids showed the emergence of an abnormal giant-cell population, and the progressive clonogenic cell loss that occurred after treatment was thought to be due to oxygen and nutrient deprivation of the remaining viable cells by this doomed cell population. Correction of the growth delay measurements for changes in cell size and clonogenic cell population allowed correlation of the growth delay and cell survival data. (author)

Acoustic Wave Propagation in Pressure Sense Lines

Science.gov (United States)

Vitarius, Patrick; Gregory, Don A.; Wiley, John; Korman, Valentin

2003-01-01

Sense lines are used in pressure measurements to passively transmit information from hostile environments to areas where transducers can be used. The transfer function of a sense line can be used to obtain information about the measured environment from the protected sensor. Several properties of this transfer function are examined, including frequency dependence, Helmholtz resonance, and time of flight delay.

Performance of highly connected photonic switching lossless metro-access optical networks

Science.gov (United States)

Martins, Indayara Bertoldi; Martins, Yara; Barbosa, Felipe Rudge

2018-03-01

The present work analyzes the performance of photonic switching networks, optical packet switching (OPS) and optical burst switching (OBS), in mesh topology of different sizes and configurations. The "lossless" photonic switching node is based on a semiconductor optical amplifier, demonstrated and validated with experimental results on optical power gain, noise figure, and spectral range. The network performance was evaluated through computer simulations based on parameters such as average number of hops, optical packet loss fraction, and optical transport delay (Am). The combination of these elements leads to a consistent account of performance, in terms of network traffic and packet delivery for OPS and OBS metropolitan networks. Results show that a combination of highly connected mesh topologies having an ingress e-buffer present high efficiency and throughput, with very low packet loss and low latency, ensuring fast data delivery to the final receiver.

Bandgap characteristics of 2D plasma photonic crystal with oblique incidence: TM case

International Nuclear Information System (INIS)

Xie Ying-Tao; Yang Li-Xia

2011-01-01

A novel periodic boundary condition (PBC), that is the constant transverse wavenumber (CTW) method, is introduced to solve the time delay in the transverse plane with oblique incidence. Based on the novel PBC, the FDTD/PBC algorithm is proposed to study periodic structure consisting of plasma and vacuum. Then the reflection coefficient for the plasma slab from the FDTD/PBC algorithm is compared with the analytic results to show the validity of our technique. Finally, the reflection coefficients for the plasma photonic crystals are calculated using the FDTD/PBC algorithm to study the variation of bandgap characteristics with the incident angle and the plasma parameters. Thus it has provided the guiding sense for the actual manufacturing plasma photonic crystal. (general)

Photon and spin dependence of the resonance line shape in the strong coupling regime

NARCIS (Netherlands)

Miyashita, Seiji; Shirai, Tatsuhiko; Mori, Takashi; De Raedt, Hans; Bertaina, Sylvain; Chiorescu, Irinel

2012-01-01

We study the quantum dynamics of a spin ensemble coupled to cavity photons. Recently, related experimental results have been reported, showing the existence of the strong coupling regime in such systems. We study the eigenenergy distribution of the multi-spin system (following the Tavis-Cummings

Photon technology. Laser process technology; Photon technology. Laser process gijutsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

For developing laser process technology by interaction between substance and photon, the present state, system, R and D issues and proposal of such technology were summarized. Development of the photon technology aims at the modification of bonding conditions of substances by quantum energy of photon, and the new process technology for generating ultra- high temperature and pressure fields by concentrating photon on a minute region. Photon technology contributes to not only the conventional mechanical and thermal forming and removal machining but also function added machining (photon machining) in quantum level and new machining technology ranging from macro- to micro-machining, creating a new industrial field. This technology extends various fields from the basis of physics and chemistry to new bonding technology. Development of a compact high-quality high-power high-efficiency photon source, and advanced photon transmission technology are necessary. The basic explication of an unsolved physicochemical phenomenon related to photon and substance, and development of related application technologies are essential. 328 refs., 147 figs., 13 tabs.

On-chip steering of entangled photons in nonlinear photonic crystals.

Science.gov (United States)

Leng, H Y; Yu, X Q; Gong, Y X; Xu, P; Xie, Z D; Jin, H; Zhang, C; Zhu, S N

2011-08-16

One promising technique for working toward practical photonic quantum technologies is to implement multiple operations on a monolithic chip, thereby improving stability, scalability and miniaturization. The on-chip spatial control of entangled photons will certainly benefit numerous applications, including quantum imaging, quantum lithography, quantum metrology and quantum computation. However, external optical elements are usually required to spatially control the entangled photons. Here we present the first experimental demonstration of on-chip spatial control of entangled photons, based on a domain-engineered nonlinear photonic crystal. We manipulate the entangled photons using the inherent properties of the crystal during the parametric downconversion, demonstrating two-photon focusing and beam-splitting from a periodically poled lithium tantalate crystal with a parabolic phase profile. These experimental results indicate that versatile and precise spatial control of entangled photons is achievable. Because they may be operated independent of any bulk optical elements, domain-engineered nonlinear photonic crystals may prove to be a valuable ingredient in on-chip integrated quantum optics.

QCD measurements in photon-photon collisions at LEP

OpenAIRE

Csilling, Akos

2001-01-01

An overview of the latest results of the LEP collaborations on QCD measurements in photon-photon collisions is presented, including measurements of the total hadronic cross-section, the production of heavy quarks and dijets and the structure functions of real and virtual photons.

Comparison of multi-pole shaping and delay line clipping pre-amplifiers for position sensitive NaI(Tl) detectors

International Nuclear Information System (INIS)

Freifelder, R.; Karp, J.S.; Wear, J.A.; Lockyer, N.S.; Newcomer, F.M.; Surti, S.; Berg, R. van

1998-01-01

NaI(Tl) position sensitive detectors have been used in medical imaging for many years. For PET applications without collimators, the high counting rates place severe demands on such large area detectors. The NaI(Tl) detectors in the PENN-PET scanners are read-out via photomultiplier tubes and preamplifiers. Those preamplifiers use a delay-line clipping technique to shorten the characteristic 240 ns fall time of the NaI(Tl) signal. As an alternative, the authors have investigated a pole-zero network to shorten the signal followed by a multi-pole shaper to produce a symmetric signal suitable for high counting rates. This has been compared to the current design by measuring the energy and spatial resolution of a single detector as a function of different preamplifier designs. Data were taken over a range of ADC integration times and countrates. The new design shows improved energy resolution with short integration times. Effects on spatial resolution and deadtime are reported for large position sensitive detectors at different countrates

Delayed luminescence in a multiparameter approach to evaluation and reduction of radiobiological risks

Science.gov (United States)

Grasso, Rosaria; Cammarata, Francesco Paolo; Minafra, Luigi; Marchese, Valentina; Russo, Giorgio; Manti, Lorenzo; Musumeci, Francesco; Scordino, Agata

2017-07-01

In the framework of the research project ETHICS "Pre-clinical experimental and theoretical studies to improve treatment and protection by charged particles" funded by the National Nuclear Physics Institute, Italy, we studied the phenomenon called delayed luminescence emitted by non-tumorigenic breast epithelial MCF10A cell line after proton irradiation at different doses (0.5, 2, 6, 9 Gy). The aim is to found possible correlations between delayed luminescence and in vitro damaging induced by ion irradiation. The first results of this research show that the delayed luminescence kinetics is proton dose dependent. An interesting correlation between delayed luminescence and clonogenic potential was observed.

Photonic time crystals.

Science.gov (United States)

Zeng, Lunwu; Xu, Jin; Wang, Chengen; Zhang, Jianhua; Zhao, Yuting; Zeng, Jing; Song, Runxia

2017-12-07

When space (time) translation symmetry is spontaneously broken, the space crystal (time crystal) forms; when permittivity and permeability periodically vary with space (time), the photonic crystal (photonic time crystal) forms. We proposed the concept of photonic time crystal and rewritten the Maxwell's equations. Utilizing Finite Difference Time Domain (FDTD) method, we simulated electromagnetic wave propagation in photonic time crystal and photonic space-time crystal, the simulation results show that more intensive scatter fields can obtained in photonic time crystal and photonic space-time crystal.

Photonic band structures solved by a plane-wave-based transfer-matrix method.

Science.gov (United States)

Li, Zhi-Yuan; Lin, Lan-Lan

2003-04-01

Transfer-matrix methods adopting a plane-wave basis have been routinely used to calculate the scattering of electromagnetic waves by general multilayer gratings and photonic crystal slabs. In this paper we show that this technique, when combined with Bloch's theorem, can be extended to solve the photonic band structure for 2D and 3D photonic crystal structures. Three different eigensolution schemes to solve the traditional band diagrams along high-symmetry lines in the first Brillouin zone of the crystal are discussed. Optimal rules for the Fourier expansion over the dielectric function and electromagnetic fields with discontinuities occurring at the boundary of different material domains have been employed to accelerate the convergence of numerical computation. Application of this method to an important class of 3D layer-by-layer photonic crystals reveals the superior convergency of this different approach over the conventional plane-wave expansion method.

Photonic band structures solved by a plane-wave-based transfer-matrix method

International Nuclear Information System (INIS)

Li Zhiyuan; Lin Lanlan

2003-01-01

Transfer-matrix methods adopting a plane-wave basis have been routinely used to calculate the scattering of electromagnetic waves by general multilayer gratings and photonic crystal slabs. In this paper we show that this technique, when combined with Bloch's theorem, can be extended to solve the photonic band structure for 2D and 3D photonic crystal structures. Three different eigensolution schemes to solve the traditional band diagrams along high-symmetry lines in the first Brillouin zone of the crystal are discussed. Optimal rules for the Fourier expansion over the dielectric function and electromagnetic fields with discontinuities occurring at the boundary of different material domains have been employed to accelerate the convergence of numerical computation. Application of this method to an important class of 3D layer-by-layer photonic crystals reveals the superior convergency of this different approach over the conventional plane-wave expansion method

Carry-chain propagation delay impacts on resolution of FPGA-based TDC

International Nuclear Information System (INIS)