Friction stir welding (FSW) has produced a great impact in several industries due to the advantages that this process presents. In particular, the automotive industry has developed a variant of the ...original process, called Friction Stir Spot Welding (FSSW), which has a strong interest related to the welding of aluminum alloys and dissimilar materials in thin sheets. Aluminum-steel welding is an actual challenge, being FSSW an alternative to produce these joints. However, the information available related to the influence of process parameters on the characteristics of aluminum-steel joints is scarce. The aim of this work was to study the effect of the pin length of the welding tool and its penetration depth, during friction stir spot welding (FSSW) of overlaps joints of AA6063 with galvanized low carbon steel. FSSW was done by changing the pins length between 0.65 and 1.5mm, and also by modifying the tool penetration depth in the welded joints. On the welded spots macro and microstructural characterization was performed, Vickers microhardness profiles were determined and Peel and Cross Tension Tests were also done. The maximum loads increased when the tool penetration depth goes up and the pin length decreased. The fracture mode was, at first, interfacial meanwhile it changed to a circumferential mode when the tool penetration depth increased and the pins length was reduced.
Commissioning and performance of the NA62 RICH detector Anzivino, G.; Aisa, D.; Barbanera, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2017, Letnik:
876
Journal Article
Recenzirano
NA62 is the last generation kaon experiment at CERN SPS aiming to study the decay K+→π+νν¯. The goal of the experiment is to measure the decay branching ratio, O(10−10), with 10% precision collecting ...about 100 K+→π+νν¯ events in three years of data taking and assuming a 10% signal acceptance. The weak signal and the huge background make the experiment very challenging. The NA62 detector must be able to reject background events from decay channels with branching ratios up to 10 orders of magnitude higher than the signal one and with similar experimental signature. In order to achieve the designed goal, good Particle Identification (PID), kinematic rejection and precise timing are required. The key element of the PID in NA62 is the Ring Imaging Cherenkov detector (RICH) to identify pions and muons and to measure the particle arrival time. After a pilot run in 2014, installation and commissioning of the detector were completed in 2015, when also the first physics run took place. Results on the detector performance will be presented together with preliminary results from the 2015 and 2016 physics runs.
Pion–Muon separation with a RICH prototype for the NA62 experiment Angelucci, B.; Anzivino, G.; Avanzini, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2010, Letnik:
621, Številka:
1
Journal Article
Recenzirano
The NA62 experiment at CERN, aimed to measure
K
+
→
π
+
ν
ν
¯
branching fraction (O(10
−10)), relies on a Neon based RICH detector for
π
/
μ
separation, time measurement and level 0 trigger. The ...experimental requirements for this detector are: a muon contamination in pion samples lower than 5×10
−3 in the momentum range 15–35
GeV/
c and a time resolution on the charged track better than 100
ps. A prototype of such a detector was built and tested in 2009; it consists of a full length (
≈
18
m
) Ne filled vessel equipped with a spherical mirror and 414 PMs on its focal plane, located about 17
m upstream of the mirror. This prototype was tested at CERN SPS on a positive hadron beam, in the required momentum range, to measure the
π
/
μ
separation and to confirm the time resolution obtained with a previous prototype; the
μ
misidentification probability is about 0.7% and the time resolution is better than 100
ps in the whole momentum range.
Construction and test of a RICH prototype for the NA62 experiment Anzivino, G.; Biino, C.; Bizzeti, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2008, Letnik:
593, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A RICH prototype has been constructed and tested. The detector was cylindrical, 17
m long and 60
cm diameter, filled with neon gas at atmospheric pressure. A spherical mirror with 17
m focal length ...was used and 96 photomultipliers were placed in the mirror focal plane. The prototype was exposed to a
200
GeV
/
c
momentum negative beam derived from the CERN SPS in the 2007 fall. The performances of the detector in terms of Cherenkov angle resolution, number of photoelectrons and time resolution are presented.
The first part of this paper will review the new results in the radiative decays of charged kaons available from the NA48/2 experiment at CERN: the first measurement of the DE and INT contribution to ...the decay K± → π±π0γ in the Tπ* region 0 < Tπ* 80 MeV and the first observation of K± → π±e+e−γ decay. Then in the second part of the paper new results on radiative hyperons decays, concerning the measurement of Ξ0 → Λγ decay asymmetry and the first observation of the Ξ0 → Λe+e− decay from NA48/I, will be reported.
The ring imaging Cherenkov detector of the NA62 experiment at CERN Cenci, P.; Anzivino, G.; Bucci, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
732
Journal Article
Recenzirano
A Ring Imaging Cherenkov (RICH) detector is the key element for particle identification in the NA62 experiment at CERN. Its purposes are to distinguish pions from muons in the momentum range from ...15GeV/c to 35GeV/c with a muon suppression factor at the 0.5% level, to measure the particle arrival time with better than 100ps resolution and to provide the reference time and a fast signal for the trigger system. This paper describes the updated detector design, the present status of the construction, the final results of a prototype beam test and a possible application of Graphics Processing Units in the NA62 trigger system based on RICH information.
•The updated design and the construction status of the NA62 RICH are described.•As NA62 requires, the RICH can distinguish μ from p at the 0.5% level.•The time resolution is below 100ps and the Cherenkov angle one is below 80μrad.•The RICH is a fundamental element of the new three-level NA62 trigger system.•GPUs can successfully manage RICH information both at L0 and L1 trigger levels.
En los últimos años, dentro de a la industria automotriz, se busca introducir partes de aluminio en reemplazo de componentes de acero para la disminución en peso de los vehículos. Estas piezas deben ...ser unidas entre sí, por ejemplo, mediante soldadura. El proceso de soldadura más utilizado dentro de la industria automotriz es la soldadura de punto por resistencia (RSW). Sin embargo, la soldadura RSW de aleaciones de aluminio presenta desventajas importantes. Dentro de este contexto se ha desarrollado una variante del proceso de soldadura por Fricción Agitación denominado Soldadura de Punto por Fricción Agitación (FSSW), el cual presenta un fuerte interés en relación a la soldadura de aleaciones de aluminio y de materiales disímiles en chapas finas. Los parámetros de soldadura afectan a las características de las juntas obtenidas. Sin embargo, es escasa la información disponible sobre la influencia de estos sobre las características de la unión, en particular para juntas disimilares y en chapa fina. El objetivo de este trabajo fue estudiar el efecto de la velocidad de rotación y la profundidad de indentación de la herramienta sobre las características de uniones disimilares soldadas por FSSW. Uniones soldadas sin defectos pudieron obtenerse con propiedades mecánicas superiores a lo que se reporta hasta el momento. La carga de rotura máxima fue de 5800 N. La longitud efectiva de unión aumentó con la indentación de la herramienta, mientras que la carga de rotura aumenta y luego disminuye. Finalmente, al soldar con 1200 RPM las propiedades mecánicas de las uniones disminuyeron, respecto a lo obtenido con 680 y 903 RPM.
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