We present an ultra-small all-silica high temperature sensor based on a reflective Fabry-Perot modal interferometer (FPMI). Our FPMI is made of a micro-cavity (approximately 4.4 microm) directly fabricated into a fiber taper probe less than 10 mum in diameter. Its sensing head is a miniaturized single mode-multimode fiber configuration without splicing. The sensing mechanism of FPMI is the interference among reflected fundamental mode and excited high-order modes at the end-faces. Its temperature sensitivity is approximately 20 pm/degrees C near the wavelength of 1550 nm. This kind of sensor can work in harsh environments with ultra-large temperature gradient, but takes up little space because of its unique geometry and small size.

The Jefferson Lab Q weak experiment determined the weak charge of the proton by measuring the parityviolating elastic scattering asymmetry of longitudinally polarized electrons from an unpolarized liquid hydrogen target at small momentum transfer. A custom apparatus was designed for this experiment to meet the technical challenges presented by the smallest and most precise ep asymmetry ever measured. Technical milestones were achieved at Jefferson Lab in target power, beam current, beam helicity reversal rate, polarimetry, detected rates, and control of helicity-correlated beam properties. The experiment employed 180 µA of 89% longitudinally polarized electrons whose helicity was reversed 960 times per second. The electrons were accelerated to 1.16 GeV and directed to a beamline with extensive instrumentation to measure helicitycorrelated beam properties that can induce false asymmetries. Møller and Compton polarimetry were used to measure the electron beam polarization to better than 1%. The electron beam was incident on a 34.4 cm liquid hydrogen target. After passing through a triple collimator system, scattered electrons between 5.8• and 11.6• were bent in the toroidal magnetic field of a resistive copper-coil magnet. The electrons inside this acceptance were focused onto eight fused silicaČerenkov detectors arrayed symmetrically around the beam axis. A total scattered electron rate of about 7 GHz was incident on the detector array. The detectors were read out in integrating mode by custom-built low-noise pre-amplifiers and 18-bit sampling ADC modules. The momentum transfer Q 2 = 0.025 GeV 2 was determined using dedicated low-current (∼100 pA) measurements with a set of drift chambers before (and a set of drift chambers and trigger scintillation counters after) the toroidal magnet.

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To improve light yield and energy resolution in large-volume neutrino detectors, light concentrators are often mounted on photomultiplier tubes to increase the detection efficiency of optical photons from scintillation or Cherenkov light induced by charged particles. We propose a method to optimize previous light concentrators design in order to attain a field of view of 90 degrees and a geometrical collection efficiency above 98%. This improvement could be crucial to Jinping and other future neutrino experiments whichever it is applicable.Comment: 7 pages, 11 figures, and 1 tabl

PANDA (anti-proton annihiliation at Darmstadt) is planned to be one of the four main experiments at the future international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is going to address fundamental questions of hadron physics and quantum chromodynamics using cooled antiproton beams with a high intensity and and momenta between 1.5 and 15 GeV/c. PANDA is designed to reach a maximum luminosity of 2 × 1032 cm−2 s. Most of the physics programs require an excellent particle identification (PID). The PID of hadronic states at the forward endcap of the target spectrometer will be done by a fast and compact Cherenkov detector that uses the detection of internally reflected Cherenkov light (DIRC) principle. It is designed to cover the polar angle range from 5° to 22° and to provide a separation power for the separation of charged pions and kaons up to 3 standard deviations (s.d.) for particle momenta up to 4 GeV/c in order to cover the important particle phase space. This document describes the technical design and the expected performance of the novel PANDA disc DIRC detector that has not been used in any other high energy physics experiment before. The performance has been studied with Monte-Carlo simulations and various beam tests at DESY and CERN. The final design meets all PANDA requirements and guarantees sufficient safety margins.

A research on the conductivity of the InP-SiO, interface reveals a localization effect related to long-range fluctuations of the surface potential. The investigation of the negative magnetoresistance effect shows that the inelastic scattering interactions of electron-electron and electron-polar optic phonon play an important role in the I n P interface and obviously affect the negative magnetoresistance. Interaction between electrons is decisively important in activated localization conductance and Mott's mobility edge model is the limit of the model obtained by neglecting the interaction.Die Untersuchung der Leitfahigkeit der InP-Si0,-Grenzflache ergibt einen Lokalisierungseffekt, der mit weitreichenden Fluktuationen des OberflachenpotentiaIs verknupft ist. Die Untersuchung des negativen Magnetowiderstands zeigt, daI3 die inelastischen Elektronen-Elektronen-und Elektronen-polare optische Phononen-Streuwechselwirkungen eine wesentliche Rolle in der InP-Grenzflache spielen und offensichtlich den negativen Magnetowiderstand beeinflussen. Die Wechselwirkung zwischen den Elektronen ist fur die aktivierte Lokalisierungsleitfahigkeit bedeutungsvoll und das Modell der Mottschen Beweglichkeitskante ist der GrenzfaIl des Modells, der durch Vernachlassigung der Wechselwirkung erhdten wird. -1) 866 Chang Hing Road, 200050 Shanghai, The People's Republic of China.

The negative magnetoresistance effect of the InP-SiO, interface is investigated. The results indicate that the inelastic interaction of electrons with polar optical phonons plays an important role in the inelastic scattering process of the system. Es wird der negative Magnetowiderstandseffekt an der InP-Si0,-Grenzflache untersucht. Die Ergebnisse zeigen, daB die inelastische Wechselwirkung der Elektronen mit polaren optischen Phononen eine wesentliche Rolle im inelastischen Streuprozel3 des Systems spielt.

Based on practical engineering, the problem of interference between underground well well in ground source heat pump is studied. The distance between the ground source heat pump wells is optimized, and the interference rule between wells in the heating period is analyzed and summarized. The results show that the closer the distance between the heating well and the monitoring well, the stronger the interference between the wells, and the smaller the interference intensity as the distance between the wells is increasing. At the same time, according to the results of the analysis of the influence of the strength coefficient, through the intensity coefficient more intuitive understanding of the interference between wells, but also more conducive to improving the development and utilization of heat pump wells. The research results are instructive for the determination of reasonable well distance of ground source heat pump. 1