1,173 research outputs found
The HERA-B Ring Imaging Cherenkov Counter
The HERA-B RICH uses a radiation path length of 2.8 m in C_4F_10 gas and a
large 24 square meters spherical mirror for imaging Cherenkov rings. The photon
detector consists of 2240 Hamamatsu multi-anode photomultipliers with about
27000 channels. A 2:1 reducing two-lens telescope in front of each PMT
increases the sensitive area at the expense of increased pixel size, resulting
in a contribution to the resolution which roughly matches that of dispersion.
The counter was completed in January of 1999, and its performance has been
steady and reliable over the years it has been in operation. The design
performance of the RICH was fully reached: the average number of detected
photons in the RICH for a beta=1 particle was found to be 33 with a single hit
resolution of 0.7 mrad and 1 mrad in the fine and coarse granularity regions,
respectively.Comment: 29 pages, 23 figure
The effect of soil conditioner on the spatial variability of soil environment
ArticleThe aim of the study was to assess and evaluate the effect of soil conditioner on the
spatial variability of soil environment. Activator PRP-SOL conditioning soil properties was
selected as a field of study. Assessment of soil environment was done through the evaluation of
selected soil properties, namely, tensile resistance of the soil and soil infiltration ability. Two
dose of PRP-SOL application was done twice in year 2015 (Autumn and Spring) and once in
2016 (Spring) with application rates 150 kg ha-1
and 140 kg ha-1
, respectively. The area was
divided into blocks where stimulators were applied and none treated as a control. The evaluation
of recorded values showed that treatability and tillage itself was significantly better on the area
which was treated by application of PRP-SOL activators. In addition, tensile resistance was
decreased by 5.71% in comparison with non-treated area of experimental field. Since the
infiltration ability is among the very important soil properties which have an effect on soil
moisture regime as well as surface runoff and therefore soil erosion. The evaluation of recorded
values has revealed the effect of treatment by PRP-SOL activators on soil infiltration ability and
therefore it results in increases infiltration of precipitation as well. Overall increase of infiltration
was recorded at value 2 mm h
-1
. It can be concluded that application of soil activators may
increase the soil conditions and therefore not only conserve soil fertility but even increase it from
the long term perspective
LAPPD operation using ToFPETv2 PETSYS ASIC
Single photon sensitive detectors used in high energy physics are, in some
applications, required to cover very large areas, and more specifically in very
strong demand with an ever finer imaging and timing capability for Cherenkov
Ring Imaging Detector (RICH) configurations. We are evaluating the Large Area
Picosecond Photo-detector (LAPPD) produced by INCOM company, as a possible
candidate for future RICH detector upgrades. In this work we perform tests on
the first generation device, which is capacitively coupled to a custom designed
anode back plane, consisting of various pixels and strips varying in size, that
allows for connecting various readout systems such as standard laboratory
equipment, as well as the TOFPET2 ASIC from PETsys company [2]. Our aim is to
evaluate what can be achieved by merging currently available technology, in
order to find directions for future developments adapted for specific uses.Comment: Twepp 2022 workshop proceeding
A novel type of proximity focusing RICH counter with multiple refractive index aerogel radiator
A proximity focusing ring imaging Cherenkov detector, with the radiator
consisting of two or more aerogel layers of different refractive indices, has
been tested in 1-4 GeV/c pion beams at KEK. Essentially, a multiple refractive
index aerogel radiator allows for an increase in Cherenkov photon yield on
account of the increase in overall radiator thickness, while avoiding the
simultaneous degradation in single photon angular resolution associated with
the increased uncertainty of the emission point. With the refractive index of
consecutive layers suitably increasing in the downstream direction, one may
achieve overlapping of the Cherenkov rings from a single charged particle. In
the opposite case of decreasing refractive index, one may obtain well separated
rings. In the former combination an approximately 40% increase in photon yield
is accompanied with just a minor degradation in single photon angular
resolution. The impact of this improvement on the pion/kaon separation at the
upgraded Belle detector is discussed.Comment: submitted to Nucl. Instr. Meth.
Readout ASICs and Electronics for the 144-channel HAPDs for the Aerogel RICH at Belle II
AbstractThe particle identification (PID) device in the endcap of the Belle detector will be upgraded to a ring imaging Cherenkov counter (RICH) using aerogel as a radiator at the Belle II experiment. We develop the electronics to read out the 70,000 channels of hit information from the 144-channel hybrid avalanche photodetectors (HAPD), of the aerogel RICH detector. A readout ASIC is developed to digitize the HAPD signals, and was used in a beam test with the prototype detector. The performance and plan of the ASIC is reported in this study. We have also designed the readout electronics for the aerogel RICH, which consist of front-end boards with the ASICs merger boards to collect data from the front-end boards. A front-end board that fits in the actual available space for the aerogel RICH electronics was produced
Observation of Bs->Ds(*)+Ds(*)- using e+e- collisions and a determination of the Bs-Bsbar width difference \Delta\Gamma_s
We have made the first observation of Bs->Ds(*)+Ds(*)- decays using 23.6 fb-1
of data recorded by the Belle experiment running on the Upsilon(5S) resonance.
The branching fractions are measured to be B(B^0_s\ra D^+_s D^-_s) =
(1.0\,^{+0.4}_{-0.3}\,^{+0.3}_{-0.2})%, B(B^0_s\ra D^{*\pm}_s D^{\mp}_s) =
(2.8\,^{+0.8}_{-0.7}\,\pm 0.7)%, and B(B^0_s\ra D^{*+}_s D^{*-}_s) =
(3.1\,^{+1.2}_{-1.0}\,\pm 0.8)%; the sum is B(B^0_s\ra D^{(*)+}_s D^{(*)-}_s) =
(6.9\,^{+1.5}_{-1.3}\,\pm 1.9)%. Assuming Bs->Ds(*)+Ds(*)- saturates decays to
CP-even final states, the branching fraction determines the ratio
\Delta\Gamma_s/cos(\phi), where \Delta\Gamma_s is the difference in widths
between the two Bs-Bsbar mass eigenstates, and \phi is a CP-violating weak
phase. Taking CP violation to be negligibly small, we obtain
\Delta\Gamma_s/\Gamma_s =
0.147^{+0.036}_{-0.030}(stat.)^{+0.044}_{-0.042}(syst.), where \Gamma_s is the
mean decay width.Comment: 13 pages, 2 figures, 2 tables. v2: text added for clarification,
version published in Phys. Rev. Letter
Search for CP violation in the decays and
We have searched for CP violation in the charmed meson decays and using 673 fb of data
collected with the Belle detector at the KEKB asymmetric-energy
collider. No evidence for CP violation is observed. We report the most
sensitive CP asymmetry measurements to date for these decays: , , , and , where the first uncertainties are statistical and
the second are systematic
Measurement of CP violating asymmetries in B^0 -> K^+K^- K^0_S decays with a time-dependent Dalitz approach
We report a measurement of violating asymmetries in decays with a time-dependent Dalitz approach. This analysis
is based on a data sample of pairs accumulated
at the resonance with the Belle detector at the KEKB
asymmetric-energy collider. As the result of an unbinned maximum
likelihood fit to the selected candidates, the mixing-induced and direct
violation parameters, and are obtained for
, and other decays. We find four solutions that describe the data. There are
\{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm
2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm
8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = &
(27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to
\phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The
values for the violating phase in are similar
but other properties of the Dalitz plot are quite different for the four
solutions. These four solutions have consistent values for
all three meson decay channels and none of them deviates significantly from
the values measured in decays with the currently
available statistics. In addition, we find no significant direct
violation.Comment: submitted to PR
Measurement of via initial state radiation at Belle
The process (=1, 2) is studied via initial
state radiation using 980 fb of data at and around the
(=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB
asymmetric-energy collider. No significant signal is observed except
from decays. Upper limits on the cross sections between
and are determined at the 90% credibility
level, which range from few pb to a few tens of pb. We also set upper limits on
the decay rate of the vector charmonium [), , and
] and charmoniumlike [, , and ] states
to .Comment: Accepted by PR
Measurement of the CP-violation Parameter sin2 with a New Tagging Method at the Resonance
We report a measurement of the CP-violation parameter sin2 at the
resonance using a new tagging method, called "-
tagging." In decays containing a neutral meson, a charged
, and a charged pion, the neutral is reconstructed in the
CP-eigenstate decay channel. The initial flavor of the neutral meson at the
moment of the decay is opposite to that of the charged and
may thus be inferred from the charge of the pion without reconstructing the
charged . From the asymmetry between - and - tagged
yields, we determine sin2 = 0.57 0.58(stat)
0.06(syst). The results are based on 121 fb of data recorded by the
Belle detector at the KEKB collider.Comment: 6 pages, 3 figures (submitted to PRL
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