Mu2e Solenoid Field Mapping System Design Feher, Sandor; DeLurgio, Patrick; Elementi, Luciano ...
IEEE transactions on applied superconductivity,
04/2018, Letnik:
28, Številka:
3
Journal Article
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The Mu2e experiment at Fermilab plans to search for charged-lepton flavor violations by looking for neutrino-less muon to electron conversions in the field of the nucleus. A complex solenoid system ...and precise knowledge of its magnetic field play a major role in the experimental approach Mu2e has chosen. It is essential to map the solenoid field up to 10 -4 accuracy. This article describes the design of the Field Mapping System Mu2e will use to measure the magnetic field. Two different mechanical mapper systems, a survey-based position determination of the in-house calibrated three-dimensional Hall probes, a motion control system, and a data acquisition and readout system are presented.
Highly efficient neutron detectors are critical in many sectors, including national security, medicine, crystallography and astronomy. The main neutron detection technologies currently used involve ...3He-gas-filled proportional counters6 and light scintillators for thermalized neutrons. Semiconductors could provide the next generation of neutron detectors because their advantages could make them competitive with or superior to existing detectors. In particular, solids with a high concentration of high-neutron-capture nuclides (such as6Li,10B) could be used to develop smaller detectors with high intrinsic efficiencies. However, no promising materials have been reported so far for the construction of direct-conversion semiconductor detectors. Here we report on the semiconductor LiInP2Se6 and demonstrate its potential as a candidate material for the direct detection of thermal neutrons at room temperature. This compound has a good thermal-neutron-capture cross-section, a suitable bandgap (2.06 electronvolts) and a favourable electronic band structure for efficient electron charge transport. We used a particles from an241Am source as a proxy for the neutron-capture reaction and determined that the compact two-dimensional (2D) LilnP2Se6 detectors resolved the full-energy peak with an energy resolution of 13.9 per cent. Direct neutron detection from a moderated PuBe source was achieved using6Li-enriched (95 per cent) LilnP2Se6 detectors with fullpeak resolution. We anticipate that these results will spark interest in this field and enable the replacement of3He counters by semiconductor-based neutron detectors.
At Argonne National Laboratory the High Energy Physics and Center for Nanoscale Materials Divisions are working on a project to develop a new generation of detector readout using high speed data ...transfer optical devices that can be implemented in particle physics or for long distances. Free-space communications devices offer the potential for reductions in mass, power, and cost of data paths for on-board trigger and readout of tracking detectors. The project involves three areas of study: light modulation, the design and construction of MEMS optical devices, and the control systems for maintaining precise laser light positioning. We demonstrate an optical link in air over one meter and with low error rate at 1 Gb/s. We demonstrate steering of an optical beam over a meter with a precision of 5 micrometers utilizing a MEMS mirror and reflected light in the feedback loop. For early testing, light modulation tests with a fiber link using Li-Niobate modulators and a data generation and error checking chip are done at 1Gb/s. Many companies and universities are developing modulators which will be incorporated into CMOS chips. We are doing radiation hardness studies for one of the materials involved. Laser light will need to be steered on to and kept centered on the detector in the presence of thermal or mechanical motion, etc. This steering will be controlled by MEMS mirrors. Polycrystalline and crystalline silicon based mirror designs are being studied. We review the current status of the project and outline plans for the future development of the system.
The multi-pixel photon counter (MPPC), also known as the silicon photo-multiplier (SiPM), is a novel, solid-state photodetector that contains an array of Geiger-mode photodiodes (called microcells ...below) to a gain in range of 10 5 -10 6 when operating at a low voltage of 40-70 V. The device also has relatively high photon detection efficiency (PDE) and fast timing response. It is also compact and insensitive to magnetic fields. These properties of the MPPC has recently created substantial interest in using the device for PET imaging. In this paper, we evaluate and compare the performance properties of three designs of 1times1 mm 2 MPPC offered by Hamamatsu for use in PET. We examine the gains of devices, and also their energy and timing resolutions when coupled to LYSO.
Objectives We sought to investigate the association between new-onset atrial fibrillation after coronary artery bypass graft (CABG) (post-operative atrial fibrillation POAF) and long-term mortality ...in patients with no history of atrial fibrillation. Background POAF predicts longer hospital stay and greater post-operative mortality. Methods A total of 16,169 consecutive patients with no history of AF who underwent isolated CABG at our institution between January 1, 1996, and December 31, 2007, were included in the study. All-cause mortality data were obtained from Social Security Administration death records. A multivariable Cox proportional hazards regression model was constructed to determine the independent impact of new-onset POAF on long-term survival after adjusting for several covariates. The covariates included age, sex, race, pre-operative risk factors (ejection fraction, New York Heart Association functional class, history of myocardial infarction, index myocardial infarction, stroke, chronic obstructive pulmonary disease, peripheral arterial disease, smoking, diabetes, renal failure, hypertension, dyslipidemia, creatinine level, dialysis, redo surgery, elective versus emergent CABG, any valvular disorder) and post-operative adverse events (stroke, myocardial infarction, acute respiratory distress syndrome, and renal failure), and discharge cardiac medications known to affect survival in patients with coronary disease. Results New-onset AF occurred in 2,985 (18.5%) patients undergoing CABG. POAF independently predicted long-term mortality (hazard ratio: 1.21; 95% confidence interval: 1.12 to 1.32) during a mean follow-up of 6 years (range 0 to 12.5 years). This association remained true after excluding from the analysis those patients who died in-hospital after surgery (hazard ratio: 1.21; 95% confidence interval: 1.11 to 1.32). Patients with POAF discharged on warfarin experienced reduced mortality during follow-up. Conclusions In this large cohort of patients, POAF predicted long-term mortality. Warfarin anticoagulation may improve survival in POAF.
Introduction
Early and safe ambulation can facilitate same‐day discharge (SDD) following catheter ablation, which can reduce resource utilization and healthcare costs and improve patient ...satisfaction. This study evaluated procedure success and safety of the VASCADE MVP venous vascular closure system in patients with atrial fibrillation (AF).
Methods
The AMBULATE SDD Registry is a two‐stage series of postmarket studies in patients with paroxysmal or persistent AF undergoing catheter ablation followed by femoral venous access‐site closure with VASCADE MVP. Efficacy endpoints included SDD success, defined as the proportion of patients discharged the same day who did not require next‐day hospital intervention for procedure/access site–related complications, and access site sustained success within 15 days of the procedure.
Results
Overall, 354 patients were included in the pooled study population, 151 (42.7%) treated for paroxysmal AF and 203 (57.3%) for persistent AF. SDD was achieved in 323 patients (91.2%) and, of these, 320 (99.1%) did not require subsequent hospital intervention based on all study performance outcomes. Nearly all patients (350 of 354; 98.9%) achieved total study success, with no subsequent hospital intervention required. No major access‐site complications were recorded. Patients who had SDD were more likely to report procedure satisfaction than patients who stayed overnight.
Conclusion
In this study, 99.7% of patients achieving SDD required no additional hospital intervention for access site–related complications during follow‐up. SDD appears feasible and safe for eligible patients after catheter ablation for paroxysmal or persistent AF in which the VASCADE MVP is used for venous access‐site closure.
This study sought to investigate the prevalence, predictors, and outcomes of patients with post-operative ventricular arrhythmia (POVA) in a large cohort of patients.
New-onset POVA after cardiac ...surgery (CS) is uncommon and has controversial prognostic value.
A total of 14,720 consecutive patients undergoing CS at Emory University between January 2004 and July 2010 were included in the study. Data on all-cause mortality were obtained from Social Security Administration death records. Multivariable regression models were constructed to determine the risk factors for POVA and to estimate the independent impact of POVA on long-term survival after adjusting for 40 different covariates.
POVA occurred in 248 patients (1.7%). Patients with POVA were older (63.5 vs. 61.6 years), had lower left ventricular ejection fraction (EF) (43.7 vs. 51.3), and had greater comorbidities (Society of Thoracic Surgeons mortality risk score of 7.2% vs. 3.1%, p < 0.001). Multivariable analysis showed that older age (odds ratio OR: 1.018 per 1-year increase, p < 0.001), emergent surgery (OR: 1.77, p = 0.019), and the presence of PVD (OR: 1.41, p = 0.049) were associated with a higher incidence of POVA, whereas higher left ventricular EF (OR: 0.97 per 1% increase, p < 0.001), mild chronic obstructive pulmonary disease (OR: 0.37, p < 0.001), and off-pump surgery (OR: O.41, p < 0.001) were associated with a lower incidence of POVA. POVA was associated with substantially increased adjusted long-term mortality (hazard rate: 2.53, p < 0.001) over 3.5 years of follow-up.
POVA is associated with increased long-term mortality after CS. Older age, PVD, lower EF, and emergent surgery are associated with a higher risk of POVA, whereas off-pump surgery seems to be protective.
Ventricular Arrhythmia After Cardiac Surgery El-Chami, Mikhael F., MD; Sawaya, Fadi J., MD; Kilgo, Patrick, MS ...
Journal of the American College of Cardiology,
12/2012, Letnik:
60, Številka:
25
Journal Article
Recenzirano
Odprti dostop
Objectives This study sought to investigate the prevalence, predictors, and outcomes of patients with post-operative ventricular arrhythmia (POVA) in a large cohort of patients. Background New-onset ...POVA after cardiac surgery (CS) is uncommon and has controversial prognostic value. Methods A total of 14,720 consecutive patients undergoing CS at Emory University between January 2004 and July 2010 were included in the study. Data on all-cause mortality were obtained from Social Security Administration death records. Multivariable regression models were constructed to determine the risk factors for POVA and to estimate the independent impact of POVA on long-term survival after adjusting for 40 different covariates. Results POVA occurred in 248 patients (1.7%). Patients with POVA were older (63.5 vs. 61.6 years), had lower left ventricular ejection fraction (EF) (43.7 vs. 51.3), and had greater comorbidities (Society of Thoracic Surgeons mortality risk score of 7.2% vs. 3.1%, p < 0.001). Multivariable analysis showed that older age (odds ratio OR: 1.018 per 1-year increase, p < 0.001), emergent surgery (OR: 1.77, p = 0.019), and the presence of PVD (OR: 1.41, p = 0.049) were associated with a higher incidence of POVA, whereas higher left ventricular EF (OR: 0.97 per 1% increase, p < 0.001), mild chronic obstructive pulmonary disease (OR: 0.37, p < 0.001), and off-pump surgery (OR: O.41, p < 0.001) were associated with a lower incidence of POVA. POVA was associated with substantially increased adjusted long-term mortality (hazard rate: 2.53, p < 0.001) over 3.5 years of follow-up. Conclusions POVA is associated with increased long-term mortality after CS. Older age, PVD, lower EF, and emergent surgery are associated with a higher risk of POVA, whereas off-pump surgery seems to be protective.
Multivariable regression models were constructed to determine the risk factors for POVA and to estimate the independent impact of POVA on long-term survival after adjusting for 46 different ...covariates.
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