Effects of passage of 200 MeV Ag9+ ions in indium phosphide at different depths

Indium phosphide sample was irradiated with 200?MeV Ag⁹⁺ ions for the fluence of 2?×?10¹³?ions?cm^?2. The sample was chemically etched down up to 240?nm depth to investigate the distribution of defects at different regions. Raman scattering and glancing incidence X-ray diffraction spectra were recorded at different depths. The stress estimated from Raman shift was found to increase with depth up to 160?nm and thereafter it decreased and at a depth of 224?nm sample did not show any stress. Phonon coherence length estimated from the Phonon Confinement Model was found to vary between 43 and 18?nm with respect to depth. Glancing incidence X-ray diffraction results revealed the decrease in crystallite size from 16.12 to 1.00?nm in different depth regions.     

Effect of ion beam irradiation on palladium (II) acetyl acetonate dispersed in polymer matrix

Composites, containing different concentrations of palladium (II) acetylacetonate in polymethyl methacrylate (PMMA) matrix were prepared by vigorous mixing. PMMA was prepared by solution polymerization technique. The composites were irradiated with a 120 MeV Ni¹⁰⁺ beam at two different fluences of 1×10¹¹ and 5×10¹² ions/cm² to study ion-induced effects on their dielectric, structural properties and surface morphology. AC electrical properties of these samples were studied in the frequency range 100 Hz to 10 MHz. The dielectric permittivity/loss shows frequency dependent behavior and it obeys the universal law of dielectric (i.e. ?α f ^n?1) for pristine and irradiated samples at high frequency. The crystalline size and crystallinity of the composites were studied by X-ray diffraction analysis. Decrease in peak intensity after irradiation signifies the amorphization which is also responsible for decrease in T _g as obtained by means of differential scanning calorimetry measurement. Fourier transform infrared spectra also support this result. Surface roughness increases upon irradiation as observed from scanning electron microscopy.     

Search for <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript> → µµ<Emphasis Type="Italic">γ</Emphasis> at large hadron collider

The branching ratio for B _s → ℓ⁺ℓ⁻ γ mode is of the same order as B _s → ℓ⁺ℓ⁻, since there is no helicity suppression in the 3-body decay mode. New Physics beyond Standard Model may affect these rates favourably for experimental observation at LHC and simultaneous measurements of the modes B _s → μ⁺μ⁻ and B _s → μ⁺μ⁻ γ at LHC experiment will indicate the basic nature of the interaction at play. A simulation study has been performed to evaluate the potential of CMS detector to observe the more difficult mode of B _s → μ⁺μ⁻γ. An upper limit of 2.08 × 10⁻⁷ on the branching ratio is expected to be achieved corresponding to an integrated luminosity of 10 fb⁻¹.     

Fourier Transform 13C NMR Analysis of Some Methaqualone Metabolites

The natural abundance carbon-13 nuclear magnetic resonance spectra of some methaqualone metabolites were recorded using the pulse fourier transform technique. The chemical shift of various carbon resonances have been assigned on the basis of the chemical shift theory, multiplicities observed in SFORD spectrum and comparison with the chemical shifts of the corresponding carbons of methaqualone.     

A new search for the atomic EDM of 129Xe at FRM-II

Permanent electric dipole moments (EDMs) arise due to the breaking of time-reversal or, equivalently, CP-symmetry. Although EDM searches have so far only set upper limits, which are many orders of magnitude larger than Standard Model (SM) predictions, the motivation for more sensitive searches is stronger than ever. A new effort at FRM-II incorporating ¹²⁹Xe and ³He as a co-magnetometer can potentially improve the current limit. The noble gas mixture of ¹²⁹Xe and ³He is simultanously polarized by spin-exchange optical pumping and then transferred into a high-performance magnetically shielded room. Inside, both species can freely precess in the presence of applied magnetic and electric fields. The precession signals are detected by LTc SQUID sensors. In EDM cells with silicon electrodes we observed spin lifetimes in excess of 2500 s without and with high-voltage applied. This meets one requirement to achieve our goal of improving the EDM limit on ¹²⁹Xe by several orders of magnitude.     

Screening effect of impurities in metals: a possible explanation of the process of cold nuclear fusion

Summary The screening length of the deuterium ion by surrounding electrons in a palladium metal lattice, as estimated using two approaches—viz. the Thomas-Fermi screening theory and the Debye screening theory for plasmas in metal—is found to be less than the interatomic separation of ordinary hydrogen molecules. This has important implications for the possibility of cold nuclear fusion at room temperature, since slight fluctuations in equilibrium conditions may drive the deuterons to fuse together. The relative magnitudes of screening length for the cold nuclear fusion regime and classical hot nuclear regimes (inertial and magnetic confinement) reveal that in the former a comparatively smaller amount of energy is needed to overcome the repulsive Coulomb barrier between two deuterium ions.     

Simulative analysis of co-existing 2.5 G/10 G asymmetric XG-PON system using RZ and NRZ data formats

In this paper, a fiber optic communication system has been employed using co-existing 10 G/2.5 G asymmetric gigabit passive optical network (XG-PON) architecture. In this system, bidirectional optical fiber has been used for upstream and downstream data transmission. The system performance has been investigated for non-return-to-zero (NRZ) and return-to-zero (RZ) data formats operating at varying bit rates by varying the length of the fiber for analyzing the feasibility of this co-existence. The results have been compared for NRZ and RZ formats for upstream and downstream data in terms of Q value and eye opening. It is observed that RZ modulation format is superior as compared to conventional NRZ format and the faithful transmission of signal has been carried up to 90 km at 1577 nm for downstream and 140 km at 1270 nm for upstream.