The Mu2e experiment at Fermilab aims at measuring the neutrinoless conversion of a negative muon into an electron and reach a single event sensitivity of 2.5x10^{-17} after three years of data ...taking. The monoenergetic electron produced in the final state, is detected by a high precision tracker and a crystal calorimeter, all embedded in a large superconducting solenoid (SD) surrounded by a cosmic ray veto system. The calorimeter is complementary to the tracker, allowing an independent trigger and powerful particle identification, while seeding the track reconstruction and contributing to remove background tracks mimicking the signal. In order to match these requirements, the calorimeter should have an energy resolution of O(5)% and a time resolution better than 500 ps at 100 MeV. The baseline solution is a calorimeter composed of two disks of BaF2 crystals read by UV extended, solar blind, Avalanche Photodiode (APDs), which are under development from a JPL, Caltech, RMD consortium. In this paper, the calorimeter design, the R&D studies carried out so far and the status of engineering are described. A backup alternative setup consisting of a pure CsI crystal matrix read by UV extended Hamamatsu MPPC's is also presented.
In this paper we present the time resolution measurements of the Lutetium-Yttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The measurements have been performed using the ...\(e^-\) beam of the Beam Test Facility (BTF) in Frascati, Italy in the energy range from 100 to 400 MeV. The calorimeter prototype consisted of twenty five 30x30x130 mm\(^3\), LYSO crystals read out by 10x10 mm\(^2\) Hamamatsu Avalanche Photodiodes (APDs). The energy dependence of the measured time resolution can be parametrized as \(\sigma_{t}(E)=a/\sqrt{E/\mathrm{GeV}} \oplus b\), with the stochastic and constant terms \(a=(51\pm1)\) ps and \(b=(10\pm4)\) ps, respectively. This corresponds to the time resolution of (\(162\pm4\)) ps at 100 MeV.
Abstract
We present a tunable metal ion beam that delivers
controllable ion currents in the picoamp range for testing of
dry-phase ion sensors. Ion beams are formed by sequential atomic
evaporation ...and single or multiple electron impact ionization,
followed by acceleration into a sensing region. Controllability of
the ionic charge state is achieved through tuning of electrode
potentials that influence the retention time in the ionization
region. Barium, lead, and cadmium samples have been used to test the
system, with ion currents identified and quantified using a
quadrupole mass analyzer. Realization of a clean Ba
2+
ion beam within a bench-top system represents an important technical
advance toward the development and characterization of barium
tagging systems for neutrinoless double beta decay searches in xenon
gas. This system also provides a testbed for investigation of novel
ion sensing methodologies for environmental assay applications, with
dication beams of Pb
2+
and Cd
2+
also demonstrated for this
purpose.
The search for neutrinoless double beta decay (\(0\nu\beta\beta\)) remains one of the most compelling experimental avenues for the discovery in the neutrino sector. Electroluminescent gas-phase time ...projection chambers are well suited to \(0\nu\beta\beta\) searches due to their intrinsically precise energy resolution and topological event identification capabilities. Scalability to ton- and multi-ton masses requires readout of large-area electroluminescent regions with fine spatial resolution, low radiogenic backgrounds, and a scalable data acquisition system. This paper presents a detector prototype that records event topology in an electroluminescent xenon gas TPC via VUV image-intensified cameras. This enables an extendable readout of large tracking planes with commercial devices that reside almost entirely outside of the active medium.Following further development in intermediate scale demonstrators, this technique may represent a novel and enlargeable method for topological event imaging in \(0\nu\beta\beta\).
Despite the relatively frequent involvement of the basal ganglia and subthalamic nucleus by multiple sclerosis (MS) plaques, movement disorders (MD), other than tremor secondary to cerebellar or ...brainstem lesions, are uncommon clinical manifestations of MS. MD were present in 12 of 733 patients with MS (1.6%): three patients had parkinsonism, two blepharospasm, five hemifacial spasm, one hemidystonia, and one tourettism. MD in patients with MS are often secondary to demyelinating disease. Also in cases without response to steroid treatment and demyelinating lesions in critical regions, it is not possible to exclude that MD and MS are causally related.
The metabolic syndrome (MetS) is characterized by the association of several disorders that increase the risk of developing cardiovascular diseases and insulin resistance. In addition to the ...development of type II diabetes, insulin resistance can also lead to many complications such as atherosclerosis, dyslipidemia and high blood pressure. Extracellular vesicles (EVs), including microvesicles (MVs) and exosomes can be considered as new biomarkers of different pathologies, and can be involved in intercellular communication.
We hypothesize that EVs could be implicated in MetS-associated insulin resistance in human endothelial cells and hepatocytes.
MVs and exosomes were isolated from plasma of non-MetS and MetS patients by serial centrifugation. Then, human aortic endothelial cells (HAoECs) and human hepatocytes (HepG2) were treated with EVs or palmitic acid for 24 hours, before stimulation with 100nM insulin for 5 minutes. Finally, we studied insulin signaling pathway by analyzing specific phosphorylated proteins: IRS1 at Tyr612, AKT at Ser473 and GSK3β at Ser9.
Neither MVs nor exosomes from nMetS and MetS patients significantly modified the capacity of insulin to induce activation of AKT pathway. Also, no effect was observed when HepG2 were treated with MVs. In contrast, exosomes from MetS, but not those from nMetS patients, were able to decrease significantly the insulin-induced phosphorylation of AKT and GSK3β, in HepG2 cells without affecting IRS1 phosphorylation.
These results provide evidence:
– of the specificity of the effects of exosomes regarding the hepatocytes but not the endothelial cells and;
– that exosomes, but not MVs, from MetS patients may contribute to the insulin resistance in hepatocytes, by impairing the AKT- GSK3β pathway in response to insulin.
Metabolic syndrome (MetS) is characterized by a cluster of interconnected risk factors – hyperglycemia, dyslipidemia, hypertension and obesity – leading to an increased risk of cardiovascular events. ...Small extracellular vesicles (sEVs) can be considered as new biomarkers of different pathologies, and they are involved in intercellular communication.
We hypothesize that sEVs are implicated in MetS-associated endothelial dysfunction.
Circulating sEVs of non-MetS (nMetS) subjects and MetS patients were isolated from plasma and characterized. Thereafter, sEV effects on endothelial function were analyzed by measuring nitric oxide (NO) and reactive oxygen species (ROS) production, and mitochondrial dynamic proteins on human endothelial aortic cells (HAoECs).
Circulating levels of sEVs positively correlated with anthropometric and biochemical parameters including visceral obesity, glycaemia, insulinemia, and dyslipidemia. Treatment of HAoECs with sEVs from MetS patients decreased NO production through the inhibition of the endothelial NO-synthase activity. Injection of MetS-sEVs into mice impaired endothelium-dependent relaxation induced by acetylcholine. Furthermore, MetS-sEVs increased DHE and MitoSox-associated fluorescence in HAoECs, reflecting enhanced cytosolic and mitochondrial ROS production which was not associated with mitochondrial biogenesis or dynamic changes. MetS patients displayed elevated circulating levels of LPS in plasma, and, at least in part, it was associated to circulating sEVs. Pharmacological inhibition and down-regulation of TLR4, as well as sEV-carried LPS neutralization, results in a substantial decrease of ROS production induced by MetS-sEVs.
These results evidence sEVs from MetS patients as potential new biomarkers for this syndrome, and TLR4 pathway activation by sEVs provides a link between the endothelial dysfunction and metabolic disturbances described in MetS.
This longitudinal and prospective study aimed at investigating the influence of some parameters,including nasal cytology and clinical findings (such as asthma, atopy, acetylsalicylic acid (ASA) ...sensitivity, ASA associated with asthma), as risk factor of post-surgical relapse of nasal-sinus polyps. One hundred sixty-one consecutive patients (92 males and 69 females, mean age 47 years), affected by bilateral nasal polyposis and who had undergone surgical nasal polypectomy (endoscopic FESS), were examined post-surgically at least every 6 months for a period of 10 years. Endoscopic exam and nasal cytology exam were carried out on all patients and their case histories were carefully examined. The association eosinophilic-mast cell cellularity and the contemporary presence of asthma + ASA sensitivity showed the highest level of relapse (OR 4.5). In conclusion, cytological data in association with certain clinical parameters can predict a high risk prognosis of relapse.
The Mu2e experiment at Fermilab will search for charged lepton flavor violation via the coherent conversion process mu- N --> e- N with a sensitivity approximately four orders of magnitude better ...than the current world's best limits for this process. The experiment's sensitivity offers discovery potential over a wide array of new physics models and probes mass scales well beyond the reach of the LHC. We describe herein the preliminary design of the proposed Mu2e experiment. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2 approval.
The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, ...separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe<6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe<7×10−13 at 90% CL set by the SINDRUM II experiment.
PDF
