The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design we proposed for a revolutionary photon detector. The main idea is to replace the classical dynode chain of a PMT with a SiPM ...(G-APD), the latter acting as an electron detector and amplifier. The aim is to match the large sensitive area of a photocathode with the performance of the SiPM technology. The VSiPMT has many attractive features. In particular, a low power consumption and an excellent photon counting capability. To prove the feasibility of the idea we first tested the performance of a special non-windowed SiPM by Hamamatsu (MPPC) as electron detector and current amplifier. Thanks to this result Hamamatsu realized two VSiPMT industrial prototypes. In this work, we present the results of a full characterization of the VSiPMT prototype.
The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a revolutionary hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists ...in replacing the classical dynode chain with a SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and great stability are among the most attractive features of the VSiPMT. In order to realize such a device we first studied the feasibility of this detector both from theoretical and experimental point of view, by implementing a Geant4-based simulation and studying the response of a special non-windowed MPPC by Hamamatsu with an electron beam. Thanks to this result Hamamatsu realized two VSiPMT industrial prototypes with a photocathode of 3mm diameter. We present the progress on the realization of a 1-inch prototype and the preliminary tests we are performing on it.
Abstract Introduction Impaired wound healing represents a common operative complication after kidney transplantation. This problem seems to be affected by factors related to surgical technique, ...drugs, and patient/graft peculiarities. Patients and Methods From January 2000 to December 2007, 350 consecutive kidney transplantations were performed in a population of nondiabetic patients. We evaluated the influence of various factors on impaired wound healing. Results Among 350 kidney transplantation patients, we observed 54 cases (15.43%) of impaired healing of the surgical incision: 36 (10.29%) with first level and 18 (5.14%) with second level wound complications. Factors related to complications were overweight and delayed graft function. Cyclosporine and tacrolimus had similar effects. However, all patients developing second level complications showed more risk factors. In our experience, postoperative lymphocele did not occur as an unique factor but became a significant risk factor when associated with another one. Patients who did not have reconstruction of the muscle layers showed a greater incidence of incisional complications. Conclusion Impaired healing of the surgical incision more or less seriously influenced outcomes of transplanted patients. This complication was common and usually related to the presence of more than one risk factor.
The experimental results on the ratios of branching fractions R(D)=B(Bover ¯→Dτ^{-}νover ¯_{τ})/B(Bover ¯→Dℓ^{-}νover ¯_{ℓ}) and R(D^{*})=B(Bover ¯→D^{*}τ^{-}νover ¯_{τ})/B(Bover ¯→D^{*}ℓ^{-}νover ...¯_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6} BBover ¯ events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.
A
bstract
Using a data sample of 980 fb
−
1
collected with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider, we study the processes of
Ξ
c
0
→
Λ
K
¯
∗
0
,
Ξ
c
0
→
Σ
0
K
¯
∗
0
, and
Ξ
...c
0
→
Σ
+
K
∗
−
for the first time. The relative branching ratios to the normalization mode of
Ξ
c
0
→
Ξ
−
π
+
are measured to be
B
Ξ
c
0
→
Λ
K
¯
∗
0
/
B
Ξ
c
0
→
Ξ
−
π
+
=
0.18
±
0.02
stat
.
±
0.01
syst
.
,
B
Ξ
c
0
→
Σ
0
K
¯
∗
0
/
B
Ξ
c
0
→
Ξ
−
π
+
=
0.69
±
0.03
stat
.
±
0.03
syst
.
,
B
Ξ
c
0
→
Σ
+
K
∗
−
/
B
Ξ
c
0
→
Ξ
−
π
+
=
0.34
±
0.06
stat
.
±
0.02
syst
.
,
where the uncertainties are statistical and systematic, respectively. We obtain
B
Ξ
c
0
→
Λ
K
¯
∗
0
=
3.3
±
0.3
stat
.
±
0.2
syst
.
±
1.0
ref
.
×
10
−
3
,
B
Ξ
c
0
→
Σ
0
K
¯
∗
0
=
12.4
±
0.5
stat
.
±
0.5
syst
.
±
3.6
ref
.
×
10
−
3
,
B
Ξ
c
0
→
Σ
+
K
∗
0
=
6.1
±
1.0
stat
.
±
0.4
syst
.
±
1.8
ref
.
×
10
−
3
,
where the uncertainties are statistical, systematic, and from
B
Ξ
c
0
→
Ξ
−
π
+
, respectively. The asymmetry parameters
α
Ξ
c
0
→
Λ
K
¯
∗
0
and
α
Ξ
c
0
→
Σ
+
K
∗
−
are 0
.
15 ± 0
.
22(stat
.
) ± 0
.
04(syst
.
) and
−
0
.
52 ± 0
.
30(stat
.
) ± 0
.
02(syst
.
), respectively, where the uncertainties are statistical followed by systematic.
A
bstract
We report the first measurement of the exclusive cross sections
e
+
e
−
→
B
B
¯
,
e
+
e
−
→
B
B
¯
∗
, and
e
+
e
−
→
B
∗
B
¯
∗
in the energy range from 10
.
63 GeV to 11
.
02 GeV. The
B
...mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy
e
+
e
−
collider.
VSiPMT a new photon detector Di Capua, F.; Barbarino, G.; Barbato, F.C.T. ...
EPJ Web of Conferences,
01/2016, Letnik:
116
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Photon detection is a key factor to study many physical processes in several areas of fundamental physics research. Focusing the attention on photodetectors for particle astrophysics, the future ...experiments aimed at the study of very high-energy or extremely rare phenomena (e.g. dark matter, proton decay, neutrinos from astrophysical sources) will require additional improvements in linearity, gain, quantum efficiency and single photon counting capability. To meet the requirements of these class of experiments, we propose a new design for a modern hybrid photodetector: the VSiPMT (Vacuum Silicon PhotoMultiplier Tube). The idea is to replace the classical dynode chain of a PMT with a SiPM, which therefore acts as an electron detector and amplifier. The aim is to match the large sensitive area of a photocathode with the performances of the SiPM technology.
Letter of intent for KM3NeT 2.0 Adrián-Martínez, S; Aharonian, F; Aiello, S ...
Journal of physics. G, Nuclear and particle physics,
08/2016, Letnik:
43, Številka:
8
Journal Article
Recenzirano
Odprti dostop
The main objectives of the KM3NeT Collaboration are (i) the discovery and subsequent observation of high-energy neutrino sources in the Universe and (ii) the determination of the mass hierarchy of ...neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: (1) the high-energy astrophysical neutrino signal reported by IceCube and (2) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure consisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the synergistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon (France), Capo Passero (Sicily, Italy) and Pylos (Peloponnese, Greece). The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three-dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely configured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary field of view, including the galactic plane. One building block will be densely configured to precisely measure atmospheric neutrino oscillations.
A
bstract
We present measurements of the branching fractions for the decays
B
→
Kμ
+
μ
−
and
B
→
Ke
+
e
−
, and their ratio (
R
K
), using a data sample of 711 fb
−
1
that contains 772 × 10
6
B
B
¯
...events. The data were collected at the ϒ(4
S
) resonance with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider. The ratio
R
K
is measured in five bins of dilepton invariant-mass-squared (
q
2
):
q
2
∈ (0
.
1
,
4
.
0)
,
(4
.
00
,
8
.
12)
,
(1
.
0
,
6
.
0), (10
.
2
,
12
.
8) and (
>
14
.
18) GeV
2
/c
4
, along with the whole
q
2
region. The
R
K
value for
q
2
∈ (1
.
0
,
6
.
0) GeV
2
/c
4
is
1.03
−
0.24
+
0.28
± 0
.
01. The first and second uncertainties listed are statistical and systematic, respectively. All results for
R
K
are consistent with Standard Model predictions. We also measure
CP
-averaged isospin asymmetries in the same
q
2
bins. The results are consistent with a null asymmetry, with the largest difference of 2.6 standard deviations occurring for the
q
2
∈ (1
.
0
,
6
.
0) GeV
2
/c
4
bin in the mode with muon final states. The measured differential branching fractions,
d
ℬ
/dq
2
, are consistent with theoretical predictions for charged
B
decays, while the corresponding values are below the expectations for neutral
B
decays. We have also searched for lepton-flavor-violating
B
→
Kμ
±
e
∓
decays and set 90% confidence-level upper limits on the branching fraction in the range of 10
−
8
for
B
+
→
K
+
μ
±
e
∓
, and
B
0
→
K
0
μ
±
e
∓
modes.
We present a measurement of R_{K^{*}}, the branching fraction ratio B(B→K^{*}μ^{+}μ^{-})/B(B→K^{*}e^{+}e^{-}), for both charged and neutral B mesons. The ratio for the charged case R_{K^{*+}} is the ...first measurement ever performed. In addition, we report absolute branching fractions for the individual modes in bins of the squared dilepton invariant mass q^{2}. The analysis is based on a data sample of 711 fb^{-1}, containing 772×10^{6} BBover ¯ events, recorded at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The obtained results are consistent with standard model expectations.
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