**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**44

# Search results for: 6MV Photon

##### 44 Simulation of Superconducting Nanowire Single-Photon Detector with Circuit Modeling

**Authors:**
Seyed Ali Sedigh Zyabari,
A. Zarifkar

**Abstract:**

**Keywords:**
NbN,
nanowire meander,
superconducting single
photon detector,
kinetic inductance.

##### 43 Two-Photon Fluorescence in N-Doped Graphene Quantum Dots

**Authors:**
Chi Man Luk,
Ming Kiu Tsang,
Chi Fan Chan,
Shu Ping Lau

**Abstract:**

Nitrogen-doped graphene quantum dots (N-GQDs) were fabricated by microwave-assisted hydrothermal technique. The optical properties of the N-GQDs were studied. The luminescence of the N-GQDs can be tuned by varying the excitation wavelength. Furthermore, two-photon luminescence of the N-GQDs excited by near-infrared laser can be obtained. It is shown that N-doping play a key role on two-photon luminescence. The N-GQDs are expected to find application in biological applications including bioimaging and sensing.

**Keywords:**
Graphene quantum dots,
nitrogen doping,
photoluminescence,
two-photon fluorescence.

##### 42 Photon Localization inside a Waveguide Modeled by Uncertainty Principle

**Authors:**
Shilpa N. Kulkarni,
Sujata R. Patrikar

**Abstract:**

**Keywords:**
photon localization in waveguide,
photon tunneling,
quantum confinement of light,
Schrödinger wave equation,
uncertainty principle.

##### 41 Absolute Cross Sections of Multi-Photon Ionization of Xenon by the Comparison with Process of its Electron-Impact Ionization

**Authors:**
A. A. Mityureva,
A. A. Pastor,
P. Yu. Serdobintsev,
N. A. Timofeev

**Abstract:**

Comparison of electron- and photon-impact processes as a method for determination of photo-ionization cross sections is described, discussed and shown to have many attractive features.

**Keywords:**
Transition probability,
cross section,
photo-ionization,
electron-ionization,
multi-photon process.

##### 40 Two-Photon Ionization of Silver Clusters

**Authors:**
V. Paployan,
K. Madoyan,
A. Melikyan,
H. Minassian

**Abstract:**

In this paper, we calculate the two-photon ionization (TPI) cross-section for pump-probe scheme in Ag neutral cluster. The pump photon energy is assumed to be close to the surface plasmon (SP) energy of cluster in dielectric media. Due to this choice, the pump wave excites collective oscillations of electrons-SP and the probe wave causes ionization of the cluster. Since the interband transition energy in Ag exceeds the SP resonance energy, the main contribution into the TPI comes from the latter. The advantage of Ag clusters as compared to the other noble metals is that the SP resonance in silver cluster is much sharper because of peculiarities of its dielectric function. The calculations are performed by separating the coordinates of electrons corresponding to the collective oscillations and the individual motion that allows taking into account the resonance contribution of excited SP oscillations. It is shown that the ionization cross section increases by two orders of magnitude if the energy of the pump photon matches the surface plasmon energy in the cluster.

**Keywords:**
Resonance enhancement,
silver clusters,
surface
plasmon,
two-photon ionization.

##### 39 Highly Efficient Silicon Photomultiplier for Positron Emission Tomography Application

**Authors:**
Fei Sun,
Ning Duan,
Guo-Qiang Lo

**Abstract:**

A silicon photomultiplier (SiPM) was designed, fabricated and characterized. The SiPM was based on SACM (Separation of Absorption, Charge and Multiplication) structure, which was optimized for blue light detection in application of positron emission tomography (PET). The achieved SiPM array has a high geometric fill factor of 64% and a low breakdown voltage of about 22V, while the temperature dependence of breakdown voltage is only 17mV/°C. The gain and photon detection efficiency of the device achieved were also measured under illumination of light at 405nm and 460nm wavelengths. The gain of the device is in the order of 10^{6}. The photon detection efficiency up to 60% has been observed under 1.8V overvoltage.

**Keywords:**
Photon Detection Efficiency,
Positron Emission Tomography,
Silicon Photomultiplier.

##### 38 Intrinsic Electromagnetic Fields and Atom-Field Coupling in Living Cells

**Authors:**
Masroor H. S. Bukhari,
Z. H. Shah

**Abstract:**

**Keywords:**
bioelectromagnetism,
cell membrane,
evanescentwaves,
photon tunnelling,
resonance

##### 37 Application of Strong Optical Feedback to Enhance the Modulation Bandwidth of Semiconductor Lasers to the Millimeter-Wave Band

**Authors:**
Moustafa Ahmed,
Ahmed Bakry,
Fumio Koyama

**Abstract:**

We report on the use of strong external optical feedback to enhance the modulation response of semiconductor lasers over a frequency passband around modulation frequencies higher than 60 GHz. We show that this modulation enhancement is a type of photon-photon resonance (PPR) of oscillating modes in the external cavity formed between the laser and the external reflector. The study is based on a time-delay rate equation model that takes into account both the strong feedback and multiple reflections in the external cavity. We examine the harmonic and intermodulation distortions associated with single and two-tone modulations in the mm-wave band of the resonant modulation. We show that compared with solitary lasers modulated around the carrier-photon resonance frequency, the present mm-wave modulated signal has lower distortions.

**Keywords:**
Distortion,
intensity modulation,
optical feedback,
semiconductor laser.

##### 36 Decoy-pulse Protocol for Frequency-coded Quantum Key Distribution

**Authors:**
Sudeshna Bhattacharya,
Pratyush Pandey,
Pradeep Kumar K

**Abstract:**

We propose a decoy-pulse protocol for frequency-coded implementation of B92 quantum key distribution protocol. A direct extension of decoy-pulse method to frequency-coding scheme results in security loss as an eavesdropper can distinguish between signal and decoy pulses by measuring the carrier photon number without affecting other statistics. We overcome this problem by optimizing the ratio of carrier photon number of decoy-to-signal pulse to be as close to unity as possible. In our method the switching between signal and decoy pulses is achieved by changing the amplitude of RF signal as opposed to modulating the intensity of optical signal thus reducing system cost. We find an improvement by a factor of 100 approximately in the key generation rate using decoy-state protocol. We also study the effect of source fluctuation on key rate. Our simulation results show a key generation rate of 1.5×10-4/pulse for link lengths up to 70km. Finally, we discuss the optimum value of average photon number of signal pulse for a given key rate while also optimizing the carrier ratio.

**Keywords:**
B92,
decoy-pulse,
frequency-coding,
quantum key distribution.

##### 35 Plug and Play Interferometer Configuration using Single Modulator Technique

**Authors:**
Norshamsuri Ali,
Hafizulfika,
Salim Ali Al-Kathiri,
Abdulla Al-Attas,
Suhairi Saharudin,
Mohamed Ridza Wahiddin

**Abstract:**

**Keywords:**
single photon,
interferometer,
quantum key distribution.

##### 34 Optical Limiting Characteristics of Core-Shell Nanoparticles

**Authors:**
G.Vinitha,
A.Ramalingam

**Abstract:**

**Keywords:**
hydrothermal method,
optical limiting devicesseeded polymerization technique,
three-photon type absorption

##### 33 Purity Monitor Studies in Medium Liquid Argon TPC

**Authors:**
I. Badhrees

**Abstract:**

This paper is an attempt to describe some of the results that had been found through a journey of study in the field of particle physics. This study consists of two parts, one about the measurement of the cross section of the decay of the Z particle in two electrons, and the other deals with the measurement of the cross section of the multi-photon absorption process using a beam of Laser in the Liquid Argon Time Projection Chamber.

The first part of the paper concerns the results based on the analysis of a data sample containing 8120 ee candidates to reconstruct the mass of the Z particle for each event where each event has an ee pair with PT_{(e)} > 20GeV, and η_{(e)} < 2.5. Monte Carlo templates of the reconstructed Z particle were produced as a function of the Z mass scale. The distribution of the reconstructed Z mass in the data was compared to the Monte Carlo templates, where the total cross section is calculated to be equal to 1432pb.

The second part concerns the Liquid Argon Time Projection Chamber, LAr TPC, the results of the interaction of the UV Laser, Nd-YAG with λ= 266mm, with LAr and through the study of the multi-photon ionization process as a part of the R&D at Bern University. The main result of this study was the cross section of the process of the multi-photon ionization process of the LAr, σ_{e} = 1.24±0.10stat±0.30sys.10 -56cm^{4}.

**Keywords:**
ATLAS,
CERN,
KACST,
LArTPC,
Particle Physics.

##### 32 Proton Radius Calculation for Muonic Hydrogen 2S-2P Transition Experiment

**Authors:**
Jing-Gang Xie

**Abstract:**

_{p}–n

_{µ}), which interacts resonantly with the incoming photon of energy 206.2949(32) meV. A similar calculation is also made for muonic deuterium 2S-2P transition experiment with an accuracy of 1% from the experimental observation. The paper has also explored the theoretical as well as experimentation advancements that have led towards the development of results with lesser deviations.

**Keywords:**
2s-2p transition,
muonic hydrogen,
proton radius,
scattering experiment,
photon,
quantum,
Lamb shift.

##### 31 Spectral Broadening in an InGaAsP Optical Waveguide with χ(3) Nonlinearity Including Two Photon Absorption

**Authors:**
Keigo Matsuura,
Isao Tomita

**Abstract:**

We have studied a method to widen the spectrum of optical pulses that pass through an InGaAsP waveguide for application to broadband optical communication. In particular, we have investigated the competitive effect between spectral broadening arising from nonlinear refraction (optical Kerr effect) and shrinking due to two photon absorption in the InGaAsP waveguide with χ(3) nonlinearity. The shrunk spectrum recovers broadening by the enhancement effect of the nonlinear refractive index near the bandgap of InGaAsP with a bandgap wavelength of 1490 nm. The broadened spectral width at around 1525 nm (196.7 THz) becomes 10.7 times wider than that at around 1560 nm (192.3 THz) without the enhancement effect, where amplified optical pulses with a pulse width of ∼ 2 ps and a peak power of 10 W propagate through a 1-cm-long InGaAsP waveguide with a cross-section of 4 (μm)2.

**Keywords:**
InGaAsP Waveguide,
χ(3) Nonlinearity,
Spectral Broadening.

##### 30 A Model for the Characterization and Selection of Beeswaxes for use as base Substitute Tissue in Photon Teletherapy

**Authors:**
R.M.V. Silva,
D.N. Souza

**Abstract:**

**Keywords:**
Beeswaxes,
characterization,
model,
radiotherapy

##### 29 Profile Calculation in Water Phantom of Symmetric and Asymmetric Photon Beam

**Authors:**
N. Chegeni,
M. J. Tahmasebi Birgani

**Abstract:**

Nowadays, in most radiotherapy departments, the commercial treatment planning systems (TPS) used to calculate dose distributions needs to be verified; therefore, quick, easy-to-use and low cost dose distribution algorithms are desirable to test and verify the performance of the TPS. In this paper, we put forth an analytical method to calculate the phantom scatter contribution and depth dose on the central axis based on the equivalent square concept. Then, this method was generalized to calculate the profiles at any depth and for several field shapes regular or irregular fields under symmetry and asymmetry photon beam conditions. Varian 2100 C/D and Siemens Primus Plus Linacs with 6 and 18 MV photon beam were used for irradiations. Percentage depth doses (PDDs) were measured for a large number of square fields for both energies, and for 45^{º} wedges which were employed to obtain the profiles in any depth. To assess the accuracy of the calculated profiles, several profile measurements were carried out for some treatment fields. The calculated and measured profiles were compared by gamma-index calculation. All γ–index calculations were based on a 3% dose criterion and a 3 mm dose-to-agreement (DTA) acceptance criterion. The γ values were less than 1 at most points. However, the maximum γ observed was about 1.10 in the penumbra region in most fields and in the central area for the asymmetric fields. This analytical approach provides a generally quick and fairly accurate algorithm to calculate dose distribution for some treatment fields in conventional radiotherapy.

**Keywords:**
Dose distribution,
equivalent field,
asymmetric field,
irregular field.

##### 28 The Photon-Drag Effect in Cylindrical Quantum Wire with a Parabolic Potential

**Authors:**
Hoang Van Ngoc,
Nguyen Thu Huong,
Nguyen Quang Bau

**Abstract:**

Using the quantum kinetic equation for electrons interacting with acoustic phonon, the density of the constant current associated with the drag of charge carriers in cylindrical quantum wire by a linearly polarized electromagnetic wave, a DC electric field and a laser radiation field is calculated. The density of the constant current is studied as a function of the frequency of electromagnetic wave, as well as the frequency of laser field and the basic elements of quantum wire with a parabolic potential. The analytic expression of the constant current density is numerically evaluated and plotted for a specific quantum wires GaAs/AlGaAs to show the dependence of the constant current density on above parameters. All these results of quantum wire compared with bulk semiconductors and superlattices to show the difference.

**Keywords:**
Photon-drag effect,
constant current density,
quantum wire,
parabolic potential.

##### 27 Equivalent Field Calculation to Irregular Symmetric and Asymmetric Photon Fields

**Authors:**
N. Chegeni,
M. J. Tahmasebi Birgani

**Abstract:**

Equivalent fields are frequently used for central axis depth-dose calculations of rectangular and irregular shaped photon beam. Since most of the proposed models to calculate the equivalent square field, are dosimetry-based, a simple physical-based method to calculate the equivalent square field size was used as the basis of this study. The table of the sides of the equivalent square for rectangular fields was constructed and then compared with the well-known tables of BJR and Venselaar with the average relative error percentage of 2.5±2.5 % and 1.5±1.5 % respectively. To evaluate the accuracy of this method, the PDDs were measured for some special irregular symmetric and asymmetric treatment fields and their equivalent squares for Siemens Primus Plus linear accelerator for both energies 6 and 18MV. The mean relative differences of PDDs measurement for these fields and their equivalent square was approximately 1% or less. As a result, this method can be employed to calculate equivalent field not only for rectangular fields but also for any irregular symmetric or asymmetric field.

**Keywords:**
Equivalent field,
asymmetric field,
irregular field,
multi leaf collimators.

##### 26 Nonlinear Absorption and Scattering in Wide Band Gap Silver Sulfide Nanoparticles Colloid and Their Effects on the Optical Limiting

**Authors:**
Hoda Aleali,
Nastaran Mansour,
Maryam Mirzaie

**Abstract:**

**Keywords:**
Nanoscale materials,
Silver sulfide nanoparticles,
Nonlinear absorption,
Nonlinear scattering,
Optical limiting.

##### 25 The Mass Attenuation Coefficients, Effective Atomic Cross Sections, Effective Atomic Numbers and Electron Densities of Some Halides

**Authors:**
Shivalinge Gowda

**Abstract:**

_{2}, CdI

_{2}and HgI

_{2}were determined at photon energies 279.2, 320.07, 514.0, 661.6, 1115.5, 1173.2 and 1332.5 keV in a well-collimated narrow beam good geometry set-up using a high resolution, hyper pure germanium detector. The mass attenuation coefficients and the effective atomic cross sections are found to be in good agreement with the XCOM values. From these mass attenuation coefficients, the effective atomic cross sections s

_{a,}of the compounds were determined. These effective atomic cross section s

_{a}data so obtained are then used to compute the effective atomic numbers Z

_{eff}. For this, the interpolation of total attenuation cross-sections of photons of energy E in elements of atomic number Z was performed by using the logarithmic regression analysis of the data measured by the authors and reported earlier for the above said energies along with XCOM data for standard energies. The best-fit coefficients in the photon energy range of 250 to 350 keV, 350 to 500 keV, 500 to 700 keV, 700 to 1000 keV and 1000 to 1500 keV by a piecewise interpolation method were then used to find the Z

_{eff}of the compounds with respect to the effective atomic cross section s

_{a}from the relation obtained by piece wise interpolation method. Using these Z

_{eff}values, the electron densities N

_{el}of halides were also determined. The present Z

_{eff}and N

_{el}values of halides are found to be in good agreement with the values calculated from XCOM data and other available published values.

**Keywords:**
Mass attenuation coefficient,
atomic cross-section,
effective atomic number,
electron density.

##### 24 De Broglie Wavelength Defined by the Rest Energy E0 and Its Velocity

**Authors:**
K. Orozović,
B. Balon

**Abstract:**

In this paper, we take a different approach to de Broglie wavelength, as we relate it to relativistic physics. The quantum energy of the photon radiated by a body with de Broglie wavelength, as it moves with velocity v, can be defined within relativistic physics by rest energy E₀. In this way, we can show the connection between the quantum of radiation energy of the body and the rest of energy E₀ and thus combine what has been incompatible so far, namely relativistic and quantum physics. So, here we discuss the unification of relativistic and quantum physics by introducing the factor k that is analog to the Lorentz factor in Einstein's theory of relativity.

**Keywords:**
de Brogli wavelength,
relativistic physics,
rest energy,
quantum physics.

##### 23 Development of Rotational Smart Lighting Control System for Plant Factory

**Authors:**
Won-Sub Lee,
Sung-Gaun Kim

**Abstract:**

**Keywords:**
Plant Factory,
Lighting Control System,
Rotational
Lighting System,
Lighting Equipment

##### 22 Relaxation Dynamics of Quantum Emitters Resonantly Coupled to a Localized Surface Plasmon

**Authors:**
Khachatur V. Nerkararyan,
Sergey I. Bozhevolnyi

**Abstract:**

We investigate relaxation dynamics of a quantum dipole emitter (QDE), e.g., a molecule or quantum dot, located near a metal nanoparticle (MNP) exhibiting a dipolar localized surface plasmon (LSP) resonance at the frequency of the QDE radiative transition. It is shown that under the condition of the QDE-MNP characteristic relaxation time being much shorter than that of the QDE in free-space but much longer than the LSP lifetime. It is also shown that energy dissipation in the QDE-MNP system is relatively weak with the probability of the photon emission being about 0.75, a number which, rather surprisingly, does not explicitly depend on the metal absorption characteristics. The degree of entanglement measured by the concurrency takes the maximum value, while the distances between the QDEs and metal ball approximately are equal.

**Keywords:**
Metal nanoparticle,
Localized surface plasmon,
Quantum dipole emitter,
Relaxation dynamics.

##### 21 Researches Concerning Photons as Corpuscles with Mass and Negative Electrostatic Charge

**Authors:**
Ioan Rusu

**Abstract:**

**Keywords:**
Electrostatic,
electron,
proton,
photon,
radiation.

##### 20 Procedure to Use Quantitative Bone-Specific SPECT/CT in North Karelia Central Hospital

**Authors:**
L. Korpinen,
P. Taskinen,
P. Rautio

**Abstract:**

This study aimed to describe procedures that we developed to use in the quantitative, bone-specific SPECT/CT at our hospital. Our procedures included the following questions for choosing imaging protocols, which were based on a clinical doctor's referral: (1) Is she/he a cancer patient or not? (2) Are there any indications of inflammatory rheumatoid arthritis? We performed about 1,106 skeletal scintigraphies over two years. About 394 patients were studied with quantitative bone-specific single-photon emission computed tomography/computerized tomography (SPECT/CT) (i.e., about 36% of all bone scintigraphies). Approximately 64% of the patients were studied using the conventional Anterior-Posterior/Posterior-Anterior imaging. Our procedure has improved efficiency and decreased cycle times.

**Keywords:**
Skeletal scintigraphy,
SPECT/CT,
imaging.

##### 19 Electron Filling Factor and Sunlight Concentration Effects on the Efficiency of Intermediate Band Solar Cell

**Authors:**
Nima Es'haghi Gorji,
Hossein Movla,
Foozieh Sohrabi,
Alireza Mottaghizadeh,
Mohammad Houshmand,
Hassan Babaei,
Arash Nikniazi

**Abstract:**

For a determined intermediate band position, the effects of electron filling factor and sunlight concentration on the active region thickness and efficiency of the quantum-dot intermediate band solar cell are calculated. For each value of electron filling factor, the maximum point of efficiency obtained and resulted in the optimum thickness of the cell under three different sunlight concentrations. We show the importance of filling factor as a parameter to be more considered. The photon recycling effect eliminated in all calculations.

**Keywords:**
Intermediate band,
Sunlight concentration,
Efficiency limits,
Electron filling factor

##### 18 A Novel Single-Wavelength All-Optical Flip-Flop Employing Single SOA-MZI

**Authors:**
H. Kaatuzian,
M. Sedghi,
S. Khatami

**Abstract:**

**Keywords:**
All Optical,
Flip-Flop,
Mach-Zehnder Interferometer
(MZI),
Semiconductor Optical Amplifier (SOA).

##### 17 Evolution of Cord Absorbed Dose during of Larynx Cancer Radiotherapy, with 3D Treatment Planning and Tissue Equivalent Phantom

**Authors:**
Mohammad Hassan Heidari,
Amir Hossein Goodarzi,
Majid Azarniush

**Abstract:**

Radiation doses to tissues and organs were measured using the anthropomorphic phantom as an equivalent to the human body. When high-energy X-rays are externally applied to treat laryngeal cancer, the absorbed dose at the laryngeal lumen is lower than given dose because of air space, which it should pass through, before reaching the lesion. Specially, in case of high-energy X-rays, the loss of dose is considerable. Three-dimensional absorbed dose distributions have been computed for high-energy photon radiation therapy of laryngeal and hypopharyngeal cancers, using a coaxial pair of opposing lateral beams in fixed positions. Treatment plans obtained under various conditions of irradiation.

**Keywords:**
3D Treatment Planning,
anthropomorphic phantom,
larynx cancer,
radiotherapy.

##### 16 Collective Oscillations in a Magnetized Plasma Subjected to a Radiation Field

**Authors:**
Daniel Santos,
Bruno Ribeiro,
Marco Amato,
Antonio Fonseca

**Abstract:**

In this paper we discuss the behaviour of the longitudinal modes of a magnetized non collisional plasma subjected to an external electromagnetic field. We apply a semiclassical formalism, with the electrons being studied in a quantum mechanical viewpoint whereas the electromagnetic field in the classical context. We calculate the dielectric function in order to obtains the modes and found that, unlike the Bernstein modes, the presence of radiation induces oscillations around the cyclotron harmonics, which are smoothed as the energy stored in the radiation field becomes small compared to the thermal energy of the electrons. We analyze the influence of the number of photon involved in the electronic transitions between the Landau levels and how the parameters such as the external fields strength, plasma density and temperature affect the dispersion relation

**Keywords:**
Collective oscillations,
External fields,
Dispersion relation.

##### 15 Size Dependence of 1D Superconductivity in NbN Nanowires on Suspended Carbon Nanotubes

**Authors:**
T. Hashimoto,
N. Miki,
H. Maki

**Abstract:**

We report the size dependence of 1D superconductivity in ultrathin (10-130 nm) nanowires produced by coating suspended carbon nanotubes with a superconducting NbN thin film. The resistance-temperature characteristic curves for samples with ≧25 nm wire width show the superconducting transition. On the other hand, for the samples with 10-nm width, the superconducting transition is not exhibited owing to the quantum size effect. The differential resistance vs. current density characteristic curves show some peak, indicating that Josephson junctions are formed in nanowires. The presence of the Josephson junctions is well explained by the measurement of the magnetic field dependence of the critical current. These understanding allow for the further expansion of the potential application of NbN, which is utilized for single photon detectors and so on.

**Keywords:**
NbN nanowire,
carbon nanotube,
quantum size effect,
Josephson junction