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Author |
Esposito, R. et al; Domingo-Pardo, C. |
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Title  |
Design of the third-generation lead-based neutron spallation target for the neutron time-of-flight facility at CERN |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review Accelerators and Beams |
Abbreviated Journal |
Phys. Rev. Accel. Beams |
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Volume |
24 |
Issue |
9 |
Pages |
093001 - 17pp |
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Abstract |
The neutron time-of-flight (n_TOF) facility at the European Laboratory for Particle Physics (CERN) is a pulsed white-spectrum neutron spallation source producing neutrons for two experimental areas: the Experimental Area 1 (EAR1), located 185 m horizontally from the target, and the Experimental Area 2 (EAR2), located 20 m above the target. The target, based on pure lead, is impacted by a high-intensity 20-GeV/c pulsed proton beam. The facility was conceived to study neutron-nucleus interactions for neutron kinetic energies between a few meV to several GeV, with applications of interest for nuclear astrophysics, nuclear technology, and medical research. After the second-generation target reached the end of its lifetime, the facility underwent a major upgrade during CERN's Long Shutdown 2 (LS2, 2019-2021), which included the installation of the new third-generation neutron target. The first- and second-generation targets were based on water-cooled massive lead blocks and were designed focusing on EAR1, since EAR2 was built later. The new target is cooled by nitrogen gas to avoid erosion-corrosion and contamination of cooling water with radioactive lead spallation products. Moreover, the new design is optimized also for the vertical flight path and EAR2. This paper presents an overview of the target design focused on both physics and thermomechanical performance, and includes a description of the nitrogen cooling circuit and radiation protection studies. |
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Address |
[Esposito, R.; Calviani, M.; Aberle, O.; Barbagallo, M.; Coiffet, T.; Dragoni, F.; Ximenes, R. Franqueira; Giordanino, L.; Grenier, D.; Kershaw, K.; Maire, V.; Moyret, P.; Fontenla, A. Perez; Perillo-Marcone, A.; Pozzi, F.; Sgobba, S.; Timmins, M.; Vlachoudis, V.] European Lab Particle Phys CERN, CH-1211 Geneva 23, Switzerland, Email: raffaele.esposito@cern.ch; |
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Amer Physical Soc |
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English |
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WOS:000696029700001 |
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no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4963 |
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Author |
Gomis, P.; Perez, A. |
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Title |
Decoherence effects in the Stern-Gerlach experiment using matrix Wigner functions |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review A |
Abbreviated Journal |
Phys. Rev. A |
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Volume |
94 |
Issue |
1 |
Pages |
012103 - 11pp |
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Abstract |
We analyze the Stern-Gerlach experiment in phase space with the help of the matrix Wigner function, which includes the spin degree of freedom. Such analysis allows for an intuitive visualization of the quantum dynamics of the device. We include the interaction with the environment, as described by the Caldeira-Leggett model. The diagonal terms of the matrix provide us with information about the two components of the state that arise from interaction with the magnetic field gradient. In particular, from the marginals of these components, we obtain an analytical formula for the position and momentum probability distributions in the presence of decoherence that shows a diffusive behavior for large values of the decoherence parameter. These features limit the dynamics of the present model. We also observe the decay of the nondiagonal terms with time and use this fact to quantify the amount of decoherence from the norm of those terms in phase space. From here, we can define a decoherence time scale, which differs from previous results that make use of the same model. We analyze a typical experiment and show that, for that setup, the decoherence time is much smaller than the characteristic time scale for the separation of the two beams, implying that they can be described as an incoherent mixture of atoms traveling in the up and down directions with opposite values of the spin projection. Therefore, entanglement is quickly destroyed in the setup we analyzed. |
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Address |
[Gomis, P.] Univ Valencia, CSIC, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Spain, Email: Pablo.Gomis@uv.es; |
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Amer Physical Soc |
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English |
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ISSN |
2469-9926 |
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Notes |
WOS:000378909000003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2739 |
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Author |
Degiovanni, A.; Wuensch, W.; Giner Navarro, J. |
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Title |
Comparison of the conditioning of high gradient accelerating structures |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review Accelerators and Beams |
Abbreviated Journal |
Phys. Rev. Accel. Beams |
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Volume |
19 |
Issue |
3 |
Pages |
032001 - 6pp |
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Abstract |
Accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved in numerous prototype CLIC accelerating structures. The conditioning and operational histories of several structures, tested at KEK and CERN, have been compared and there is clear evidence that the conditioning progresses with the number of rf pulses and not with the number of breakdowns. This observation opens the possibility that the optimum conditioning strategy, which minimizes the total number of breakdowns the structure is subject to without increasing conditioning time, may be to never exceed the breakdown rate target for operation. The result is also likely to have a strong impact on efforts to understand the physical mechanism underlying conditioning and may lead to preparation procedures which reduce conditioning time. |
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Address |
[Degiovanni, Alberto; Wuensch, Walter] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland, Email: walter.wuensch@cern.ch |
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Amer Physical Soc |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9888 |
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Conference |
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Notes |
WOS:000400274700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3090 |
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Author |
Hinarejos, M.; Di Franco, C.; Romanelli, A.; Perez, A. |
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Title |
Chirality asymptotic behavior and non-Markovianity in quantum walks on a line |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review A |
Abbreviated Journal |
Phys. Rev. A |
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Volume |
89 |
Issue |
5 |
Pages |
052330 - 7pp |
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Abstract |
We investigate the time evolution of the chirality reduced density matrix for a discrete-time quantum walk on a one-dimensional lattice. The matrix is obtained by tracing out the spatial degree of freedom. We analyze the standard case, without decoherence, and the situation in which decoherence appears in the form of broken links in the lattice. By examining the trace distance for possible pairs of initial states as a function of time, we conclude that the evolution of the reduced density matrix is non-Markovian, in the sense defined by Breuer, Laine, and Piilo [Phys. Rev. Lett. 103, 210401 (2009)]. As the level of noise increases, the dynamics approaches a Markovian process. The highest non-Markovianity corresponds to the case without decoherence. The reduced density matrix tends always to a well-defined limit that we calculate, but only in the decoherence-free case is this limit nontrivial. |
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Address |
[Hinarejos, Margarida; Perez, Armando] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1050-2947 |
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Notes |
WOS:000336751300003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1807 |
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Author |
Senes, E.; Argyropoulos, T.; Tecker, F.; Wuensch, W. |
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Title |
Beam-loading effect on breakdown rate in high-gradient accelerating cavities: An experiment at the Compact Linear Collider Test Facility at CERN |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physical Review Accelerators and Beams |
Abbreviated Journal |
Phys. Rev. Accel. Beams |
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Volume |
21 |
Issue |
10 |
Pages |
102001 - 8pp |
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Keywords |
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Abstract |
Radio frequency breakdown rate is a crucial performance parameter that ensures that the design luminosity is achieved in the CLIC linear collider. The required low breakdown rate for CLIC, of the order of 10(-7) breakdown pulse(-1) m(-1), has been demonstrated in a number of 12 GHz CLIC prototype structures at gradients in excess of the design 100 MV/m accelerating gradient, however without the presence of the accelerated beam and associated beam loading. The beam loading induced by the approximately 1 A CLIC main beam significantly modifies the field distribution inside the structures, and the effect on breakdown rate is potentially significant so needs to be determined. A dedicated experiment has been carried out in the CLIC Test Facility CTF3 to measure this effect, and the results are presented. |
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Address |
[Senes, Eugenio] John Adams Inst, Denys Wilkinson Bldg,Keble Rd, Oxford OX1 3RH, England, Email: eugenio.senes@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9888 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000447731900003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3768 |
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