TPG, test results Ableev, V.; Ambrosino, F.; Apollonio, M. ...
IEEE transactions on nuclear science,
12/2005, Letnik:
52, Številka:
6
Journal Article
Recenzirano
TPG is the acronym for Time Projection Chamber with GEM amplification, high-granularity hexaboard read-out and FADC electronics. We have constructed a TPG read-out module, called TPG-head, with three ...GEM foils and a multilayer board, called hexaboard, covered with 710 000 hexagonal pads of 300 mum size. The total active area of this module is a disk of 30 cm diameter. The 710 000 pads are read by three sets of 576 strips dephased by 120 degrees. Each strip is read by a FADC channel with 100 ns sampling time. The module is mounted in a test-bed formed by a cylindrical field cage of 80 cm diameter and 150 cm length inside a solenoidal magnet that operates with a magnetic field up to B=0.7 Tesla. Tests with X-ray sources show an intrinsic spatial resolution of the order of 40 mum. The threshold for transverse momentum measurement of low energy tracks is below 0.1 MeV/c with a magnetic field of 0.07 Tesla. At 0.7 Tesla the intrinsic space point resolution of the chamber is such that the error on the measurement of the transverse momentum is DeltaP t sime0.1 MeV/c in absence of distortions from the drift region
The OBELIX spectrometer, studying at the Low Energy Antiproton Ring (LEAR) of CERN the
N̄N annihilation, has collected annihilation data with very low momentum
p̄(≈ 50
MeV/c). The results of the ...spin-parity analysis on the
p̄p annihilation into four and five pions are briefly described.
TPG construction Ableev, V.; Ambrosino, F.; Apollonio, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
535, Številka:
1
Journal Article
Recenzirano
TPG is the acronym for a 3D imaging gas chamber with GEM amplification, hexaboard read-out and FADC electronics. We have constructed a TPG-head with three GEM foils (30
cm diameter) and a read-out ...board (30
cm diameter active surface) covered with 710,000 hexagonal pads of
300
μ
m
size. Aligned pads are connected in parallel to one strip out of three sets of 576 parallel strips (
500
μ
m
pitch). The three sets of strips run at
120
∘
from each other and at three different depths inside the hexaboard multilayer structure. Each strip is read out by FADC electronics. The TPG-head is under initial test in a small container with a drift volume 33
mm long and of 30
cm diameter. A 150
cm long drift volume inside a 0.7
T solenoidal magnetic field has been prepared by using HARP-TPC instrumentation as test bed.
TPG development Ableev, V.; Ambrosino, F.; Apollonio, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
1
Journal Article
Recenzirano
TPG is the acronym for Time Projection chamber with GEM amplification, hexaboard read-out and FADC electronics. We are constructing a TPG read-out module with three GEM foils (30
cm diameter) and a ...read-out board (30
cm diameter active surface) covered with hexagonal pads of 300
μm size. Aligned pads are connected in parallel to one strip out of three sets of parallel strips. Each strip is read by FADC electronics. The test bench for the TPG head will be the HARP-TPC field cage. TPG characteristics, design and expected performances are discussed.
The annihilation fractions and cross sections for the
n
̄
p
annihilation reaction in flight (∼50–400 MeV/
c) into
ηπ
+ and
η′
π
+ final states have been measured. The first ones follow the trend ...expected for P wave annihilations. From the ratios of the yields an evaluation of the pseudoscalar mixing angle in the standard form is possible. The value found shows that for pseudoscalar meson production from P wave the Quark Line Rule is not grossly violated.
We report the study of light baryon production in two-prong annihilation reactions due to antiprotons stopping in gaseous deuterium and detected by the OBELIX spectrometer (LEAR, CERN). A clear ...signal of the
Δ(1232) production in binary reactions was found in both annihilation channels:
p
̄
d→π
−Δ
+(Δ
+→π
0p)
and
p
̄
d→π
0Δ
0(Δ
0→π
−p)
. The annihilation probabilities for these reactions turned out to be
Y=(1.01±0.08)×10
−5 and
Y=(1.12±0.20)×10
−5, respectively. In addition, the annihilation probability for the prototype Pontecorvo reaction
p
̄
d→π
−p
was measured with the best world statistics:
Y=(1.46±0.08)×10
−5.
The results of a study of the annihilation reactions
np → θπ
+
and
np → ωπ
+
are reported; the data were collected by the OBELIX apparatus, with antineutrons annihilating in flight (momenta from ∼ 50 ...MeV/
c to 405 MeV/
c). Annihilation frequencies and annihilation cross sections have been deduced, for both channels, as a function of antineutron momentum. From the cross section ratio, a substantial deviation from OZI rule expectations is observed. An
ss
quark content in the nucleon offers a fairly plausible explanation for such an effect.
PDF
![Study of [formula omitted] ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0375-9474/small "Study of [formula omitted] and [formula omitted] annihilation reactions in flight")