Some aspects of measurements with a 127° cylindrical analyzer

In the case of a 127° cylindrical deflector without optics on the entrance side, a non-zero transmission for a beam of charged particles with an angle of incidence appreciably different from the normal one is possible. This may cause a remarkable error in the energy analysis of particles; the error rises with the angle and the particle energy. The existence of a maximum in a plot of energy vs angle of incidence (which is symmetric) occurring at normal incidence makes it possible to exclude this error.     

Performance analysis of a novel architecture for contention resolution of OPS

Optical packet switching (OPS) technology can rapidly deliver the enormous network bandwidth and offer high-speed data rate and format transparency. In this paper we propose a novel architecture using all-optical tunable wavelength converters (TWCs) and fiber delay-lines (FDLs) to address the contention problem for OPS in wavelength and time domains. This architecture improves packet switching speed but significantly decreases the number of optical switches comparing with existing architectures. A simulation is also conducted to evaluate the performance of the architecture. The simulation results show that the packet loss probability of this architecture is lower than general architectures.     

Status of an experiment aimed at laboratory searches for the electron-antineutrino magnetic moment at a level of μ ν ≤3±10− μ B

An experiment aimed at directly detecting antineutrino-electron scattering by using a 40-MCi tritium β-active source will make it possible to lower the present-day laboratory limit on the neutrino magnetic moment by two orders of magnitude. The experiment brings together novel unique technologies in studying rare processes of neutrino-electron scattering: (i) an artificial source of antineutrinos from tritium decay of 40-MCi activity with the antineutrino flux density of about 6×10¹⁴ cm^?2 s^?1 and (ii) new types of detectors capable of detecting electrons of energy down to about 10 eV, namely, a silicon cryogenic detector based on the ionization-into-heat conversion effect and a high-pure germanium detector with an internal signal amplification in the electric field. A compact installation located at a specially equipped underground laboratory (≤100 mwe) will provide favorable background conditions for running the experiment. With a background level of about 0.1 event/(kg keV d) and detector assembly masses of 3 and 5 kg for the silicon and germanium ones, respectively, a limit of μ _ν ≤3±10^? μ _B on the electron-antineutrino magnetic moment will be obtained within 1 to 2 years of data acquisition. The status of the experiment and the state of the art are presented.     

Bhabha versus Møller scattering as a contact-interaction analyzer at a polarized Linear Collider

We discuss electron-electron contact-interaction searches in the processes and at planned Linear Colliders run in the e ⁺ e ^- and e ^- e ^- modes with both beams longitudinally polarized. Our analysis is based on the measurement, for the two processes, of polarized differential cross sections, and allows one to simultaneously take into account the general set of electron contact-interaction couplings as independent, non-zero, parameters thus avoiding the simplifying choice of a model. We evaluate the corresponding model-independent constraints on the contact coupling constants, emphasizing the role of the available beam polarization and the complementarity, as far as the chirality of the constants is concerned, of the two processes in giving the best constraints. Received: 15 October 2002, Revised: 28 April 2003, Published online: 18 June 2003     

Study of D_s~±→μ~±V_μ at Belle

We present a preliminary measurement of the B(D_s→μν_μ)with the Belle experiment at the KEKB collider.We select D~s→μV_μdecays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction.The results are based on a data sample of 550 fb~(-1)and are compared to similar measurements by other experiments as well as to the predictions of LQCD.We conclude with short prospects for improvements in the accuracy of the measurement.     

Study of D±s→μ±vμ at Belle

We present a preliminary measurement of the B(Ds→μvμ) with the Belle experiment at the KEKB collider. We select Ds→μvμ decays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction. The results are based on a data sample of 550 fb-1 and are compared to similar measurements by other experiments as well as to the predictions of LQCD. We conclude with short prospects for improvements in the accuracy of the measurement.     

Antenna measurements of open-structure Schottky mixers and determination of optical elements for a heterodyne system at 184, 214 and 287 μm

Antenna patterns of open structure Schottky mixers were measured at 184, 214 and 287 μm. For use in a heterodyne detector system the antenna pattern must be matched to the signal beam, for example the astronomical signal of a telescope, and the optically coupled local oscillator beam. The procedure of determining a lens system is described and the successful application in astronomical observations with the Kuiper Airborne Observatory (KAO) is shown.     

Measurements of the mid-rapidity parity violating spin asymmetries for W ± bosons at PHENIX

The parity violating W ^± single spin asymmetry, in longitudinally polarized p + p collisions, can give us a clean way to access the $\Delta \bar u$ and $\Delta \bar d$ polarized parton distribution functions. The current status of the analysis of the 2011 data set and future prospects will be presented.     

Design of resolution testing facility for ultraviolet imager

We present a resolution testing system of ultraviolet (UV) imager.In this system,an UV Czerny-Turner monochromator with a small f-number is designed to get more energy as an UV radiation source,and its stray light is rejected effectively by light traps.And UV diffuser is employed in order to get uniform light distribution on the resolving power test target.We also design a novel UV collimator which makes infinite UV testing targets.It can reduce the difficulty of optical design and the machining cost,and utilize UV energy at maximum extent.This facility has been applied in the imaging quality evaluation of the UV instrument,and the results accord with the theoretical analysis.     

Alternate intensity modulation of a dual-wavelength He−Ne laser for differential absorption measurements

A simple method is demonstrated for internal intensity modulation of the 3.391 and 3.392-m emissions of a He–Ne laser with equal amplitudes and 180° out of phase to each other. A modulation amplitude of 0.7 mW peak-to-peak at 1kHz for the individual emissions has been obtained from a laser plasma tube 50 cm long while maintaining the total-intensity modulation as low as 0.25 W for a signal averaging time of 1 s. This laser source can greatly simplify the setup and improve the sensitivity of differential absorption measurements for the methane remote sensing.     

Methane analyzer based on TDL’s for measurements in the lower stratosphere: design and laboratory tests

This paper describes a tunable diode laser spectrometer for the in situ measurement of methane by high-resolution absorption spectroscopy of roto-vibrational lines, using a distributed feedback laser emitting in the near infrared (1.65 μm) and a multi-pass cell, with a two-tone detection scheme. The instrument was designed to be installed on the high-altitude aircraft M55 Geophysica, for high-sensitivity and high-temporal-resolution measurement of CH₄, both as a greenhouse gas and as a tracer of air-mass motion. The instrument-design criteria to achieve the compactness, low weight, and ruggedness necessary for automatic operation on an unpressurized high-altitude aircraft are reported. Results of the laboratory testing are also shown and discussed. Received: 1 April 2002 / Revised version: 28 May 2002 / Published online: 12 September 2002 RID="*" ID="*"Corresponding author. Fax: +39-050/313-7597, E-mail: damato@scintec.it     

Study of K ± → e ± νπ 0 decays at the KMN setup

K ^± → e ^± νπ ⁰ decays have been studied using the KMN setup at the Institute for High Energy Physics (Protvino). The experiment has been performed in the 36-GeV/c hadron beams of the IHEP accelerator. The accumulated data allow us to select ～1.08M candidates for K _e3 decays. Analyzing the Dalitz plot of these events, we estimate the linear slope of the charge form factor to be λ ₊ = [30.44 ± 0.83(stat.) ± 0.74(syst.)] × 10^?3.     

On the possibility for precision measurements of differential cross sections for elastic proton–proton scattering at the Protvino accelerator

Elastic-scattering data were analyzed, and it was concluded on the basis of this analysis that precisionmeasurements of differential cross sections for elastic proton–proton scattering at the accelerator of the Institute for High Energy Physics (IHEP, Protvino, Russia) over a broad momentum-transfer range are of importance and topical interest. The layout of the respective experimental facility detecting the scattered particle and recoil proton and possessing a high momentum-transfer resolution was examined along with the equipment constituting this facility. The facility in question is able to record up to a billion events of elastic proton–proton scattering per IHEP accelerator run (20 days). Other lines of physics research with this facility are briefly discussed.     

Characterization of a Chelyabinsk LL5 meteorite fragment using Mössbauer spectroscopy with a high velocity resolution

The first study of a Chelyabinsk LL5 ordinary chondrite fragment was carried out using Mössbauer spectroscopy with a high velocity resolution at 295 and 90 K. The Mössbauer parameters of the measured spectra were evaluated and room temperature data were compared with previously obtained results of the study of ordinary chondrites using Mössbauer spectroscopy with a high velocity resolution.     

New interpretation of C–V measurements for determining the concentration profile in a semiconductor

The well-known C–V technique for determining the doping profile in a semiconductor is re-examined. Based on an analysis of the Poisson equation, a modification of the conventional procedure for evaluating the space-charge density distribution within the depletion layer of a semiconductor is presented. This procedure involves a developed integral-capacitance technique, which proves to be generally valid and gives the correct basis for determining the space-charge density near the edge of the depletion layer rather than the real doping profile. The relationship between the proposed method and the conventional differential-capacitance technique is revealed and a comparison of the effectiveness of both of them is also made. The method proves to be useful if shallow diffusion profiles within low-doped substrates are analyzed, when the conventional C–V profiling technique is not applicable. Experimental results obtained with an n⁺/n epitaxial layer are given and discussed as an illustration of the represented study. Received: 18 September 2000 / Accepted: 4 December 2000 / Published online: 3 May 2001