PEP-II B-factory operates at a record high circulating current currently ~2.5 A in the positron ring. Electron cloud effects became apparent [1] when the positron ring current reached ~ 0.7 A with a bunch current ~1.5 mA. Initially, electron cloud induced beam instabilities significantly limited collider luminosity [2]. However, suppression of the electron cloud related beam instabilities have ...

Ultra-thin metallic anodic and cathodic wires are frequently employed in low-mass gaseous detectors for precision experiments, where the amount of material crossed by charged particles must be minimised. We present here results an analysis mechanical stress chemical corrosion effects observed $40$ $50~{\rm{\mu m}}$ diameter silver plated aluminum mounted within volume MEG\,II drift chamber, whi...

In the MEG II detector, measurement of momentum charged particle is performed by a high transparency single volume, full stereo cylindrical Drift Chamber (CDCH). It composed 9 concentric layers, each consisting 192 drift cells. The cell approximately squared, with 20 μm gold plate tungsten sense wire surrounded 40 μm/50 silver plated aluminum field wires in ratio 5:1. During construction first ...

The fluorination of Yttria (Y2O3) coatings in the inner chamber wall a plasma-etching equipment causes process drift. In this paper, we investigate relationship between microstructure and fluoride layer Y2O3 prepared by aerosol deposition (AD) method compared with atmospheric plasma spraying (APS) ion plating (IP). corrosion AD-coating, which has highly dense without any pores, proceeded homoge...

The work presented focuses on the measurement of Ja e plots and determination of ion recombination factors for plane parallel ionisation chambers used in pulsed electron beams. The ability to measure the Ja e plots accurately is useful when commisioning a new chamber and the ion recombination correction factor needs to be known when the chamber is calibrated in a beam quality di erent from the ...

Measurements are presented of ion energy distributions produced within a prototype NSTAR discharge chamber as a function of its operational parameters. The goal of this effort is to document the ion energy distribution characteristics and determine features that could cause rapid sputter erosion of discharge chamber components. Ion energy distributions were measured with a Comstock model AC-901...

introduction: wind erosion is one of the most important factors in desert environments. prevailing winds can shift sand dunes and affect their accumulation and morphology. also, wind regime determines the direction of sand dune mobility in different ways. therefore, the wind regime, frequency, direction and velocity are supposed to be the most important factors to form the morphology of sand du...

A new setup for measuring partial photoion-yields was developed and build at the Synchrotron Radiation Center. The chamber, which accomodates an ion Time-of-Flight (TOF) spectrometer, a metal vapor oven, and a cooling trap, consists mainly of a standard conflat 6" 6-way cross and a 6" tee. The base pressure of the chamber is in the 10 mbar region and rises into the 10 mbar region when the oven ...