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SUMMARY:The new Cylindrical GEM Inner Tracker of the BESIII experiment: te
 st beam results of two prototypes.
DTSTART;VALUE=DATE-TIME:20170302T020000Z
DTEND;VALUE=DATE-TIME:20170302T022000Z
DTSTAMP;VALUE=DATE-TIME:20260510T105410Z
UID:indico-contribution-1764@indico.inp.nsk.su
DESCRIPTION:Speakers: Lia Lavezzi (INFN and IHEP)\nA cylindrical GEM detec
 tor is under development\, to serve as an upgraded inner tracker at the BE
 SIII spectrometer. It will consist of three layers of cylindrically-shaped
  triple GEMs surrounding the interaction point. The experiment is taking d
 ata at the e$^{+}$e$^{-}$ collider BEPCII in Beijing (China) and the GEM t
 racker will be installed in 2018. \nTests on the performances of triple GE
 Ms in strong magnetic field have been run by means of the muon beam availa
 ble in the H4 line of SPS (CERN) with both planar chambers and the first c
 ylindrical prototype. Efficiencies and resolutions have been evaluated usi
 ng different gains\, gas mixtures\, with and without magnetic field.\nThe 
 obtained efficiency is larger than 95%\, in many operational arrangements.
   \nThe spatial resolution for planar GEMs has been evaluated with two dif
 ferent algorithms for the position determination: the charge centroid and 
 the micro time projection chamber (TPC) methods. The two modes are complem
 entary and are able to cope with the asymmetry of the electron avalanche w
 hen running in magnetic field\, and with non-orthogonal incident tracks. \
 nWith the charge centroid\, a resolution lower than 100 microns has been r
 eached without magnetic field and lower than 200 microns with a magnetic f
 ield up to 1 T. The micro TPC mode showed to be able to improve those resu
 lts. \nIn the first beam test with the cylindrical prototype\, the detecto
 r had a very good stability under different voltage configurations and par
 ticle intensities. The resolution evaluation is in progress.\n\nhttps://in
 dico.inp.nsk.su/event/8/contributions/1764/
LOCATION:
URL:https://indico.inp.nsk.su/event/8/contributions/1764/
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