The ATHENA antihydrogen apparatus Amoretti, M.; Amsler, C.; Bonomi, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The ATHENA apparatus that recently produced and detected the first cold antihydrogen atoms is described. Its main features, which are described herein, are: an external positron accumulator, making ...it possible to accumulate large numbers of positrons; a separate antiproton catching trap, optimizing the catching, cooling and handling of antiprotons; a unique high resolution antihydrogen annihilation detector, allowing an clear determination that antihydrogen has been produced; an open, modular design making variations in the experimental approach possible and a “nested” Penning trap situated in a cryogenic, 3T magnetic field environment used for the mixing of the antiprotons and positrons.
The Pauli exclusion principle (PEP) has been tested for nucleons (n,p) in \({}^{12}{\rm C}\) and \({}^{16}{\rm O}\) nuclei, using the results of background measurements with the prototype of the ...Borexino detector, the Counting Test Facility (CTF). The approach consisted of a search for \(\gamma\), n, p and/or \(\alpha\)’s emitted in a non-Paulian transition of 1P- shell nucleons to the filled 1S1/2 shell in nuclei. Similarly, the Pauli-forbidden \(\beta^{\pm}\) decay processes were searched for. Due to the extremely low background and the large mass (4.2 tons) of the CTF detector, the following most stringent up-to-date experimental bounds on PEP violating transitions of nucleons have been established: \(\tau({}^{12}{\rm C} \rightarrow {}^{12}{\rm\widetilde C} + \gamma) > 2.1\cdot10^{27} \mathrm y\), \(\tau({}^{12}{\rm C} \rightarrow {}^{11}{\rm\widetilde B} + p) > 5.0\cdot10^{26} {\mathrm{y}}\), \(\tau({}^{12}{\rm C} ({}^{16}{\rm O}) \rightarrow {}^{11}{\rm\widetilde C} ({}^{15}{\rm\widetilde O} ) + n) > 3.7 \cdot 10^{26} {\mathrm{y}}\), \(\tau({}^{12}{\rm C} \rightarrow {}^{8}{\rm\widetilde{Be}} + \alpha) > 6.1 \cdot 10^{23} \mathrm y\), \(\tau({}^{12}{\rm C} \rightarrow {}^{12}{\rm\widetilde N} + e^- + \widetilde{\nu_e}) > 7.6 \cdot 10^{27} \mathrm y\) and \(\tau({}^{12}{\rm C} \rightarrow {}^{12}{\rm\widetilde B} + e^ + + \nu_e) > 7.7 \cdot 10^{27} \mathrm y\), all at \(90 \%\) C.L.
The Borexino detector at the Laboratori Nazionali del Gran Sasso Back, H.; Balata, M.; de Bellefon, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2009, Letnik:
600, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the ...real-time measurement of sub-MeV solar neutrinos, and particularly of the monoenergetic (862
keV)
7Be electron capture neutrinos, via neutrino–electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography).
The results of background measurements with the second version of the BOREXINO Counting Test Facility (CTF-II), installed in the Gran Sasso Underground Laboratory, were used to obtain limits on the ...instability of nucleons, bounded in nuclei, for decays into invisible channels (inv): disappearance, decays to neutrinos, etc. The approach consisted of a search for decays of unstable nuclides resulting from N and NN decays of parent 12C, 13C and 16O nuclei in the liquid scintillator and the water shield of the CTF. Due to the extremely low background and the large mass (4.2 t) of the CTF detector, the most stringent (or competitive) up-to-date experimental bounds have been established: τ(n→inv)>1.8×1025 yr, τ(p→inv)>1.1×1026 yr, τ(nn→inv)>4.9×1025 yr and τ(pp→inv)>5.0×1025 yr, all at 90% C.L.
We report the direct measurement of the {sup 7}Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV ...{sup 7}Be neutrinos is 49{+-}3{sub stat}{+-}4{sub syst} counts/(day{center_dot}100 ton). The hypothesis of no oscillation for {sup 7}Be solar neutrinos is inconsistent with our measurement at the 4{sigma} C.L. Our result is the first direct measurement of the survival probability for solar {nu}{sub e} in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of {sup 7}Be, pp, and CNO solar {nu}{sub e}, and the limit on the effective neutrino magnetic moment using solar neutrinos.
Uterine cancer is today the upcoming neoplasia in gynaecological oncology. In Western countries endometrial cancer is mostly diagnosed after menopause and often becomes apparent with atypical uterine ...bleeding. Because of the great importance of such disease a series of accurate diagnostic analyses which require an adequate expenditure by hospital structures become necessary. Transvaginal sonography (TVS) remains the first choice to diagnose atypical bleeding because it is less invasive and highly bearable by the patients. TVS exam allows the selection of all patients who have an endometrial thickness more than 5 mm and/or with an inhomogeneous endometrial line thickness, who would then undergo further analyses. To achieve the diagnosis, office hysteroscopy carried out in an outpatient departments, is the most useful exam. Such exam allows a complete overview of the uterine cavity with possible detection of smaller lesions and a specific sampling of histological material. Hysteroscopy is today an indispensable aid in last resort diagnosis of endometrial cancer and is highly tolerated by patients.
We report the direct measurement of the 7Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7Be ...neutrinos is 49+/-3stat+/-4syst counts/(day.100 ton). The hypothesis of no oscillation for 7Be solar neutrinos is inconsistent with our measurement at the 4sigma C.L. Our result is the first direct measurement of the survival probability for solar nu(e) in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7Be, pp, and CNO solar nu(e), and the limit on the effective neutrino magnetic moment using solar neutrinos.
The results of background measurements with the prototype of the Borexino detector (CTF) have been used to obtain an upper bound on the neutrino magnetic moment, μν. The new upper limit for μν from ...pp and 7Be solar neutrinos is (5.5×10−10)μB (90% c.l.) in the Standard Solar Model scenario. This is the first limit on μν obtained using sub-MeV neutrinos. The sensitivity of the prototype to the neutrino charge radius and the neutrino radiative decay are also presented.
We report the direct measurement of the 7Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7Be ...neutrinos is 49±3stat±4syst counts/(day·100 ton). The hypothesis of no oscillation for 7Be solar neutrinos is inconsistent with our measurement at the 4σ C.L. Our result is the first direct measurement of the survival probability for solar νe in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7Be, pp, and CNO solar νe, and the limit on the effective neutrino magnetic moment using solar neutrinos.
The liquid handling systems for the Borexino solar neutrino detector Alimonti, G.; Avanzini, M.B.; Back, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2009, Letnik:
609, Številka:
1
Journal Article
Recenzirano
The successful deployment of the Borexino solar neutrino detector required assorted physical and chemical operations to produce exceptional pure fluids and fill multiple detector zones. The ...composition and flow rates of high purity gases and liquids had to be precisely controlled to maintain liquid levels and pressures. The system was required to meet exceptional requirements for cleanliness and leak-tightness. A large scale modular system connecting fluid receiving, purification and fluid delivery processes was developed for Borexino. At the core is a flow control system that delivers scintillator components to plants for purification, and then fills the Borexino detector volumes with ultrahigh purity buffer or ultrahigh purity scintillator. The liquid handling system maintains precise control over the liquid levels and differential pressures between the different volumes of the detectors that are separated by flexible nylon vessels. The preparation, commissioning and operation of the system for filling the Borexino detector with scintillator is described.
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