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[show abstract]
[hide abstract]
ABSTRACT: With the newly gained interest in the time of flight method for positron
emission tomography (TOF-PET), many options for pushing the time resolution to
its borders have been investigated. As one of these options the exploitation of
the Cherenkov effect has been proposed, since it allows to bypass the
scintillation process and therefore provides almost instantaneous response to
incident 511keV annihilation photons. Our simulation studies on the yield of
Cherenkov photons, their arrival rate at the photon detector and their angular
distribution reveal a significant influence by Cherenkov photons on the rise
time of inorganic scintillators - a key-parameter for TOF in PET. A measurement
shows the feasibility to detect Cherenkov photons in this low energy range.
05/2013;
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[show abstract]
[hide abstract]
ABSTRACT: Several types of Silicon Photomultipliers were exposed to short pulsed (~ 30
ps) laser light with its intensity varying from single photon to well above the
number of microcells of the device. We observed a significant deviation of the
output of SiPMs from the expected behaviour although such response curve is
considered to be rather trivial. We also noticed that the output exceeds the
maximum pulse height, i.e. single photon pulse height times the total number of
pixels. At the highest light intensity (~ 500 times the number of pixels) that
we tested, the signal output reached up to twice the maximum pulse height, and
still did not fully saturate.
04/2013;
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E. Widmann,
M. Diermaier,
B. Juhasz,
C. Malbrunot,
O. Massiczek,
C. Sauerzopf, K. Suzuki,
B. Wünschek,
J. Zmeskal,
S. Federmann,
N. Kuroda,
S. Ulmer,
Y. Yamazaki
[show abstract]
[hide abstract]
ABSTRACT: A measurement of the hyperfine structure of antihydrogen promises one of the
best tests of CPT symmetry. We describe an experiment planned at the Antiproton
Decelerator of CERN to measure this quantity in a beam of slow antihydrogen
atoms.
Hyperfine Interactions 01/2013; · 0.21 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The production of double-strangeness by antiproton annihilation in nuclei will be an exciting way to investigate whether the
formation of deeply bound antikaonic nuclear clusters occurs. The existence of deeply bound antikaonic nuclear clusters is
a lively debated problem in hadron physics today, which can be solved only experimentally. At CERN with the Antiproton Decelerator
(AD) and in future with the new FAIR facility at Darmstadt low energy antiprotons are available to perform this type of experiments.
The use of antiprotons for the production of double-strangeness was recently discussed by Weise and Kienle and indeed, it
would be very challenging to produce and study such “double-strange nuclei” in the view of the prediction of Akaishi and Yamazaki
that double-antikaon bound nuclear systems with strangeness (S = − 2) will be formed with binding energies up to 200–300MeV. Such binding energies might result in an increase of the average
density to more than 3 times the average nuclear density. If such dense systems are created, conditions in the phase diagram
might be reached where phase transition to kaon condensation or colour superconductivity will occur at low temperature.
Hyperfine Interactions 04/2012; 194(1):249-254. · 0.21 Impact Factor
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K. Suzuki,
P. Bühler,
L. Fabbietti,
N. Herrmann,
P. Kienle,
M. Kis,
Y. Leifels,
J. Marton,
E. Widmann,
T. Yamazaki,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: We search for the most fundamental kaonic nuclear state, K
−
pp by employing the reaction p + p→K
+ + X at 3.0 GeV incident beam energy. The experiment makes use of the SIS-18 synchrotron and the ~4π acceptance FOPI apparatus in the cave-B at the GSI, Darmstadt, Germany and aims to collect full kinematics information of
the reaction. We look for a signature of the X ( ≡ K
−
pp) in both missing mass spectrum by measuring K
+ , and invariant mass spectrum by measuring decay particles; X → Λ + p. The experiment is planned to take place in 2009.
Hyperfine Interactions 04/2012; 193(1):189-194. · 0.21 Impact Factor
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T. Yamazaki,
P. Kienle, K. Suzuki,
M. Maggiora,
on behalf of DISTO Collaboration,
M. Alexeev,
F. Balestra,
Y. Bedfer,
R. Bertini,
L. C. Bland, [......],
D. Panzieri,
H. -W. Pfaff,
G. Pontecorvo,
A. Popov,
J. Ritman,
P. Salabura,
V. Tchalyshev,
F. Tosello,
S. E. Vigdor,
G. Zosi
[show abstract]
[hide abstract]
ABSTRACT: We have analyzed data of the DISTO experiment on the exclusive pp → K
+ Λp process at T
p
= 2.85GeV to search for a K
−
pp ( ≡ X) nuclear bound state to be formed in the pp → K
+ + X reaction. The deviation spectra of the K
+ missing-mass ΔM (K
+ ) and Λp invariant-mass M(Λp) with selection of large-angle proton emission revealed a structure with M
X
= 2265 ±2MeV/c
2 and Γ
X
= 118 ±8MeV.
Hyperfine Interactions 04/2012; 193(1):181-187. · 0.21 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: A prototype of a position sensitive photo-detector with 5.6 x 5.6 cm2
detection area readout with 64 Hamamatsu MPPCs (S10931-100P) with 3 x 3 mm2
active area each has been built and tested. The photo-sensors are arranged in a
8 x 8 array with a quadratic mirror light guide on top. The module is currently
readout by in-house developed preamplifier boards but employing existing ASIC
chips optimized for SiPM readout is also planned. Such a device is one of the
candidates to be used for photon detection in the PANDA DIRC detectors.
11/2011;
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K Asahi,
T Furukawa,
T Inoue,
A Yoshimi,
T Nanao,
M Chikamori, K Suzuki,
M Tsuchiya,
H Hayashi,
M Uchida,
H Ueno,
Y Matsuo,
T Fukuyama
[show abstract]
[hide abstract]
ABSTRACT: Development of a nuclear spin oscillator intended for the experimental search for an electric dipole moment in 129Xe atom is reported. The spin oscillation is brought about by polarizing 129Xe nuclear spins by spin exchange with optically polarized Rb atoms, detecting the spin precession through the transmission of a circularly polarized laser light, and applying a feedback field according to the detected spins. Until present, a frequency precision, in a measurement time of T = 45,000 s, of δν = 5.2 nHz has been achieved.
Journal of Physics Conference Series 07/2011; 302(1):012039.
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C. Schwarz,
G. Ahmed,
A. Britting,
P. Bühler,
E. Cowie,
V. Kh. Dodokhov,
M. Düren,
D. Dutta,
W. Eyrich,
K. Föhl, [......],
G. Schepers,
L. Schmitt,
J. Schwiening,
B. Seitz,
C. Sfienti, K. Suzuki,
F. Uhlig,
A. S. Vodopianov,
D. P. Watts,
W. Yu
[show abstract]
[hide abstract]
ABSTRACT: Cooled antiproton beams of unprecedented intensities in the momentum
range of 1.5-15 GeV/c will be used for the P¯ANDA experiment
at FAIR to perform high precision experiments in the charmed quark
sector. The proposed P¯ANDA detector is a 4π internal target
spectrometer at the HESR allowing the detection and identification of
neutral and charged particles generated within the total energy range of
the antiproton annihilation products. The detector is divided in a
forward spectrometer and a target spectrometer. The charged particle
identification in the latter is performed by ring imaging Cherenkov
counters employing the DIRC principle.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 04/2011; 639:169-172. · 1.21 Impact Factor
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P. Kienle,
M. Maggiora, K. Suzuki,
T. Yamazaki,
M. Alexeev,
F. Balestra,
Y. Bedfer,
R. Bertini,
L. C. Bland,
A. Brenschede, [......],
D. Panzieri,
H. -W. Pfaff,
G. Pontecorvo,
A. Popov,
J. Ritman,
P. Salabura,
V. Tchalyshev,
F. Tosello,
S. E. Vigdor,
G. Zosi
[show abstract]
[hide abstract]
ABSTRACT: Analyzing DISTO data of $pp -> p Lambda K^+$ at $T_p = 2.50$ and 2.85 GeV to
populate a previously reported X(2265) resonance with $M_X = 2267$ MeV/$c^2$
and $Gamma_X = 118$ MeV at 2.85 GeV, we found that the production of X(2265) at
2.50 GeV is much less than that at 2.85 GeV (less than 10%), though it is
expected from a kinematical consideration to be produced as much as 33% of that
at 2.85 GeV. The small population of X(2265) at 2.50 GeV is consistent with the
very weak production of Lambda (1405) at the same incident energy toward its
production threshold, thus indicating that Lambda (1405) plays an important
role as a doorway state for the formation of X(2265).
02/2011;
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L. Fabbietti,
H. Angerer,
R. Beck,
M. Berger,
F. Böhmer,
K. -T. Brinkmann,
P. Bühler,
M. Danner,
S. D\orheim,
C. Funke, [......],
M. Vandenbroucke,
B. Voss,
D. Walter,
Q. Weitzel,
E. Widmann,
A. Winnebeck,
L. Wörner,
H. -G. Zaunick,
X Zhang,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: We report on the development of a GEM-based TPC prototype for the PANDA experiment. The design and requirements of this device will be illustrated, with particular emphasis on the properties of the recently tested GEM-detector, the characterization of the read-out electronics and the development of the tracking software that allows to evaluate the GEM-TPC data. Comment: submitted to NIMA 4 pages, 6 pictures
04/2010;
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[show abstract]
[hide abstract]
ABSTRACT: Silicon photomultipliers are very versatile photo detectors due to their high photon detection efficiency, fast response, single photon counting capability, high amplification, and their insensitivity to magnetic fields. At our institute we are studying the performance of these photo detectors at various operating conditions. On the basis of the experience in the laboratory we built a prototype of a timing Cherenkov detector consisting of a quartz radiator with two $3\times 3$ mm$^2$ MPPCs S10362-33-100C from Hamamatsu Photonics as photodetectors. The MPPC sensors were operated with Peltier cooling to minimize thermal noise and to avoid gain drifts. The test measurements at the DA$\Phi$NE Beam-Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) with pulsed 490 MeV electrons and the results on timing performance with Cherenkov photons are presented. Comment: Conference proceedings of 12th Vienna Conference on Instrumentation 2010
04/2010;
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T Yamazaki,
M Maggiora,
P Kienle, K Suzuki,
A Amoroso,
M Alexeev,
F Balestra,
Y Bedfer,
R Bertini,
L C Bland, [......],
A Maggiora,
D Panzieri,
H-W Pfaff,
G Pontecorvo,
A Popov,
J Ritman,
P Salabura,
S Sosio,
V Tchalyshev,
S E Vigdor
[show abstract]
[hide abstract]
ABSTRACT: We have analyzed data of the DISTO experiment on the exclusive pp --> pLambdaK+ reaction at 2.85 GeV to search for a strongly bound compact K- pp(approximately = X) state to be formed in the pp --> K+ + X reaction. The observed spectra of the K+ missing mass and the pLambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak of 26-sigma confidence with a mass M(X)=2267+/-3(stat)+/-5(syst) MeV/c2 and a width Gamma(X)=118+/-8(stat)+/-10(syst) MeV. The enormously large cross section indicates formation of a compact K- pp with a large binding energy of B(K)=103 MeV, which can be a possible gateway toward cold and dense kaonic nuclear matter.
Physical Review Letters 04/2010; 104(13):132502. · 7.37 Impact Factor
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T Yamazaki,
M Maggiora,
P. Kienle, K Suzuki,
A Amoroso,
M. Alexeev,
F Balestra,
Y Bedfer,
R Bertini,
L. C. Bland, [......],
A Maggiora,
D Panzieri,
H. -W. Pfaff,
G Pontecorvo,
A. Popov,
J. Ritman,
P. Salabura,
S Sosio,
V. Tchalyshev,
S. E. Vigdor
[show abstract]
[hide abstract]
ABSTRACT: We have analyzed data of the DISTO experiment on the exclusive pp -> p Lambda K+ reaction at 2.85 GeV to search for a strongly bound compact K-pp (= X) state to be formed in the pp -> K+ + X reaction. The observed spectra of the K+ missing-mass and the p Lambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak with a mass M_X = 2265 +- 2 (stat) +- 5 (syst) MeV/c2 and a width Gamma_X = 118 +- 8 (stat) +- 10 (syst) MeV. Comment: 4 pages, 4 figures
02/2010;
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Vazquez Doce O,
J. Zmeskal,
M. Bazzi,
M. Bragadireanu,
P. Buhler,
M. Cargnelli,
C. Curceanu,
F. Ghio,
C Guaraldo,
M. Iliescu, [......],
S Okada,
D. Pietreanu,
Poli Lener M,
A. Rizzo,
Romero Vidal A,
A. Scordo,
D. Sirghi,
A. d’Ufizzi,
E. Widmann,
B. Wunschek
[show abstract]
[hide abstract]
ABSTRACT: A preliminar study of these kind of hadronic interactions is being done by the AMADEUS collaboration by analyzing the existent KLOE data.
EPJ Web of Conferences. 01/2010;
-
S. Ajimura,
G Beer,
H. Bhang,
M. Bragadireanu,
P. Buehler,
L Busso,
M. Cargnelli,
S Choi,
C. Curceanu,
S Enomoto, [......],
T Suzuki,
H. Tatsuno,
M Tokuda,
D. Tomono,
A Toyoda,
K Tsukada,
E. Widmann,
T Yamazaki,
H Yim,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K− pp, by the in-flight 3He(K−,n) reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron and the invariant mass via the expected decay, K− pp → Λp → pπ− p. In this report, an overview of the experiment and the preparation status are presented.
EPJ Web of Conferences. 01/2010;
-
M Maggiora,
P. Kienle, K Suzuki,
T Yamazaki,
DISTO Collaboration: M. Alexeev,
A Amoroso,
F Balestra,
Y Bedfer,
R Bertini,
L. C. Bland, [......],
A Maggiora,
D Panzieri,
S Sosio,
H. -W. Pfaff,
G Pontecorvo,
A. Popov,
J. Ritman,
P. Salabura,
V. Tchalyshev,
S. E. Vigdor
[show abstract]
[hide abstract]
ABSTRACT: The data from the DISTO Collaboration on the exclusive pp -> p K+ Lambda production acquired at T_p = 2.85 GeV have been re-analysed in order to search for a deeply bound K- pp (= X) state, to be formed in the binary process pp -> K+ X. The preliminary spectra of the DeltaM_{K+} missing-mass and of the M_{p Lambda} invariant-mass show, for large transverse-momenta of protons and kaons, a distinct broad peak with a mass M_X = 2265 +- 2 MeV/c^2 and a width Gamma_X = 118 +- 8 MeV/c^2. Comment: 8 pages, 4 figures. Talk presented at the "10th International Conference on Hypernuclear and Strange Particle Physics" (HYP-X), Tokai, Ibaraki, Japan, September 14th-18th, 2009. To appear in the proceedings
12/2009;
-
[show abstract]
[hide abstract]
ABSTRACT: At the Stefan Meyer Institute/Vienna (SMI) studies are performed on the application of new matrix avalanche photo-detectors (SiPMs) operating in the Geiger-mode. Possible applications are the photo detection in scintillating fiber detectors and Cherenkov detectors. We tested the newest generation of SiPMs concerning static properties as well as specific properties like timing performance. We evaluated several kinds of SiPMs from different manufacturers with different sizes of cells, sensitive area and with different photo sensitivity. The operating temperature of the SiPM sensors could be lowered below 0 oC by using Peltier cooling. A fast pulsed blue laser system was used to evaluate the timing performance of the devices. The timing resolution was tested at various (low) light levels. This work concentrates on the effect of temperature-dependent dark current and noise as well as the timing performance as a function of the light intensity. Tests of SiPMs with high photon detection efficiency manufactured by Hamamatsu were performed in order to find optimum sensors for applications in Cherenkov detectors. Results on dark current as a function of temperature, dark count rate and timing performance obtained so far will be given.
Journal of Instrumentation 09/2009; 4(09):P09004. · 1.87 Impact Factor
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M L Benabderrahmane,
N Herrmann,
K Wiśniewski,
J Kecskemeti,
A Andronic,
V Barret,
Z Basrak,
N Bastid,
P Buehler,
M Cargnelli, [......],
Z Tymiński,
E Widmann,
Z G Xiao,
T Yamazaki,
I Yushmanov,
X Y Zhang,
A Zhilin,
J Zmeskal,
E Bratkovskaya,
W Cassing
[show abstract]
[hide abstract]
ABSTRACT: The K0 meson production by pi(-) mesons of 1.15 GeV/c momentum on C, Al, Cu, Sn, and Pb nuclear targets was measured with the FOPI spectrometer at the Schwer-Ionen-Synchrotron accelerator of GSI. Inclusive production cross sections and the momentum distributions of K0 mesons are compared to scaled elementary production cross sections and to predictions of theoretical models describing the in-medium production of kaons. The data represent a new reference for those models, which are widely used for interpretation of the strangeness production in heavy-ion collisions. The presented results demonstrate the sensitivity of the kaon production to the reaction amplitudes inside nuclei and point to the existence of a repulsive KN potential of 20+/-5 MeV at normal nuclear matter density.
Physical Review Letters 06/2009; 102(18):182501. · 7.37 Impact Factor
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Medical Physics - MED PHYS. 01/2009; 36(6).
