Nucl.Instrum.Meth.A540:295-304,2005 A small drift chamber was read out by means of a MediPix2 readout chip as
direct anode. A Micromegas foil was placed 50 $\mu$m above the chip, and
electron ...multiplication occurred in the gap. With a He/Isobutane 80/20 mixture,
gas multiplication factors up to tens of thousands were achieved, resulting in
an efficiency for detecting single electrons of better than 90% . We recorded
many frames containing 2D images with tracks from cosmic muons. Along these
tracks, electron clusters were observed, as well as delta-rays.
New results from GridPix detectors Bilevych, Y.; Blanco Carballo, V.M.; Chefdeville, M. ...
2008 IEEE Nuclear Science Symposium Conference Record,
2008-Oct.
Conference Proceeding
Odprti dostop
GridPix detector prototypes have been made using a TimePix pixel chip and a PSI 46 pixel chip. A system of discharge protection has been successfully tested. GridPix detectors have been tested using ...cosmic rays, a 90 Sr source and the T9 test beam facility at CERN. GridPix detectors perform well for 3D track reconstruction, dE/dx measurements and transition radiation detection.
A small drift chamber was read out by means of a MediPix2 readout chip as direct anode. A Micromegas foil was placed 50 \(\mu\)m above the chip, and electron multiplication occurred in the gap. With ...a He/Isobutane 80/20 mixture, gas multiplication factors up to tens of thousands were achieved, resulting in an efficiency for detecting single electrons of better than 90% . We recorded many frames containing 2D images with tracks from cosmic muons. Along these tracks, electron clusters were observed, as well as delta-rays.
During the years 1994–1997, the emulsion target of the CHORUS detector was exposed to the Wide Band Neutrino Beam from the CERN-SPS. About 170000 neutrino interactions were successfully located in ...the emulsion. Improvements in the automatic emulsion scanning systems and application of different criteria allowed the sample of located events to be used for studies of charm production. We present a measurement of the production rate of D0 mesons based on a sample of 25693 located νμ charged-current (CC) interactions analysed so far. After reconstruction of the event topology in the vertex region, 283 D0 decays were observed with an estimated background of 9.2 K0 and Λ decays. The ratio of cross-section of D0 production and νμ CC interactions is found to be (1.99±0.13(stat.)±0.17(syst.))×10−2 at 27 GeV average νμ energy.
A first analysis of the complete set of data collected by CHORUS in the years 1994–1997 is presented. The search for
ν
τ
charged current events has been performed for both leptonic and hadronic ...decays of the
τ lepton. No
τ candidate has been found. A
ν
μ
→
ν
τ
mixing is excluded down to sin
22
θ
μτ
=6.8×10
−4 for large
Δm
2 (90% C.L.).
We report on the first direct observation of a neutrino induced charged-current interaction with two subsequent decays of short-lived particles close to the interaction vertex. This rare double-kink ...signature in the CHORUS emulsion target is interpreted as a
D
s
∗+
production followed by the decay chain
D
s
∗+→D
s
+γ,D
s
+→τ
+ν
τ,
τ
+→μ
+ν
μ
ν
τ
̄
. The event is characterised by small
Q
2 and small four-momentum transfer squared
t to the target nucleon, which indicates a diffractive production mechanism. A complete analysis of the event is presented.
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