We introduce selective area grown hybrid InAs/Al nanowires based on molecular beam epitaxy, allowing arbitrary semiconductor-superconductor networks containing loops and branches. Transport reveals a ...hard induced gap and unpoisoned 2e-periodic Coulomb blockade, with temperature dependent 1e features in agreement with theory. Coulomb peak spacing in parallel magnetic field displays overshoot, indicating an oscillating discrete near-zero subgap state consistent with device length. Finally, we investigate a loop network, finding strong spin-orbit coupling and a coherence length of several microns. These results demonstrate the potential of this platform for scalable topological networks among other applications.
The planned upgrade of the A Large Ion Collider Experiment (ALICE) inner tracking system (ITS) aims at improving the ALICE performance in terms of spatial resolution and data rate readout. The new ...ITS will be a low-material-budget, high-granularity detector. It comprises seven concentric layers of monolithic active pixel sensors (MAPS), called ALPIDE, which are based on the TowerJazz 180-nm CMOS technology. In this article, we report on detection performance and radiation hardness studies of ALPIDE sensors. We show that these sensors keep having high detection efficiency for minimum ionizing particles (MIPs) (>99%) and low fake-hit rate while being radiation hard to some <inline-formula> <tex-math notation="LaTeX">{ 1.7} \times { 10}^{ 13}\,\,1 </tex-math></inline-formula> MeV <inline-formula> <tex-math notation="LaTeX">\text{n}_{\text {eq}} </tex-math></inline-formula> cm −2 of nonionizing energy loss (NIEL) and 2.7 Mrad of total ionization dose (TID), which exceeds the expected radiation load during the detector lifetime ten times. ALPIDE sensors thus completely fulfill the design requirements. In addition, we show that measured cluster shape frequencies obtained at different operating points (thresholds, bias voltages) are well described with the state-of-the-art ALICE Monte Carlo simulation.
This paper presents the design of a front-end circuit for monolithic active pixel sensors. The circuit operates with a sensor featuring a small, low-capacitance (< 2 fF) collection electrode and is ...integrated in the DPTS chip, a proof-of-principle prototype of 1.5 mm × 1.5 mm including a matrix of 32 × 32 pixels with a pitch of 15 μm. The chip is implemented in the 65 nm imaging technology from the Tower Partners Semiconductor Co. foundry and was developed in the framework of the EP-R&D program at CERN to explore this technology for particle detection. The front-end circuit has an area of 42 μm 2 and can operate with a power consumption as low as 12 nW. Measurements on the prototype relevant to the front-end will be shown to support its design.
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The HADES data from p + Nb collisions at a center-of-mass energy of
GeV are analyzed employing a statistical hadronization model. The model can successfully describe the production yields of the ...identified hadrons
,
,
,
K
0
s
,
with parameters
MeV and
MeV, which fit well into the chemical freeze-out systematics found in heavy-ion collisions. In addition, we reanalyze our previous HADES data from Ar + KCl collisions at
GeV with an updated version of the model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit as a function of colliding energy and system size. Despite its success, the model fails to describe the observed
yields in both, p + Nb and Ar + KCl . Special emphasis is put on feed-down contributions from higher-lying resonance states as a possible explanation for the observed excess.
Results on the production of the double strange cascade hyperon Ξ^{-} are reported for collisions of p(3.5 GeV)+Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI ...Helmholtzzentrum for Heavy-Ion Research, Darmstadt. For the first time, subthreshold Ξ^{-} production is observed in proton-nucleus interactions. Assuming a Ξ^{-} phase-space distribution similar to that of Λ hyperons, the production probability amounts to P_{Ξ^{-}}=2.0±0.4(stat)±0.3(norm)±0.6(syst)×10^{-4} resulting in a Ξ^{-}/(Λ+Σ^{0}) ratio of P_{Ξ^{-}}/P_{Λ+Σ^{0}}=1.2±0.3(stat)±0.4(syst)×10^{-2}. Available model predictions are significantly lower than the measured Ξ^{-} yield.
We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n+p ...reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e−>0.15 GeV/c2 is about an order of magnitude larger in n+p reactions as compared to p+p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C+C reactions are compatible with a superposition of elementary n+p and p+p collisions, leaving little room for additional electron pair sources in such light collision systems.
We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics ...measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e− invariant mass spectra to elementary p+p data, we observe for e+e− momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.
We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al ...heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature T^{*} is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, T^{*} is also tuned by a magnetic flux.
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