Search results for "detector"
showing 10 items of 3491 documents
Mapping of the magnetic field to correct systematic effects in a neutron electric dipole moment experiment
2021
Experiments dedicated to the measurement of the electric dipole moment of the neutron require outstanding control of the magnetic-field uniformity. The neutron electric dipole moment (nEDM) experiment at the Paul Scherrer Institute uses a Hg199 co-magnetometer to precisely monitor temporal magnetic-field variations. This co-magnetometer, in the presence of field nonuniformity, is, however, responsible for the largest systematic effect of this measurement. To evaluate and correct that effect, offline measurements of the field nonuniformity were performed during mapping campaigns in 2013, 2014, and 2017. We present the results of these campaigns, and the improvement the correction of this eff…
STATUS OF STRANGENESS ELECTRO-PRODUCTION AT MAMI
2009
At the Institut für Kernphysik in Mainz, Germany, the microtron MAMI has been upgraded to 1.5 GeV electron beam energy and can now be used to study strange hadronic systems. The magnetic spectrometer KAOS from GSI was dismantled and re-installed in the spectrometer facility operated by the A1 collaboration. The spectrometer's primary purpose is to study strangeness electro-production. Its compact design and its capability to detect negative and positive charged particles simultaneously under forward scattering angles complements the existing spectrometers. In 2008, an important milestone has been reached by the successful measurement of kaon production off a liquid hydrogen target. The ide…
Triacylglycerol Analysis in Human Milk and Other Mammalian Species: Small-Scale Sample Preparation, Characterization, and Statistical Classification …
2015
In this work, a method for the separation of triacylglycerols (TAGs) present in human milk and from other mammalian species by reversed-phase high-performance liquid chromatography using a core–shell particle packed column with UV and evaporative light-scattering detectors is described. Under optimal conditions, a mobile phase containing acetonitrile/n-pentanol at 10 °C gave an excellent resolution among more than 50 TAG peaks. A small-scale method for fat extraction in these milks (particularly of interest for human milk samples) using minimal amounts of sample and reagents was also developed. The proposed extraction protocol and the traditional method were compared, giving similar results…
Direct mass measurements on neutron-deficient xenon isotopes with the ISOLTRAP mass spectrometer
2002
The masses of Xe isotopes with 124 A 114 have been measured using the ISOLTRAP spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of 500000 was chosen resulting in an accuracy of m 12 keV for all isotopes investigated. Con icts with existing mass data of several standard deviations were found. peerReviewed
Status and development of the MARA low-energy branch
2018
The MARA Low-Energy Branch is under development at the Accelerator Laboratory of the University of Jyvaskylä. The facility will be employed for laser ionisation and spectroscopy studies and for mass measurements of nuclei close to the proton drip line. This article presents an updated status of the ongoing development of the different parts of this facility, including the buffer gas cell, the ion transport system, the laser system and the detector stations. peerReviewed
SPI/INTEGRAL in-flight performance
2003
The SPI instrument has been launched on-board the INTEGRAL observatory on October 17, 2002. SPI is a spectrometer devoted to the sky observation in the 20 keV-8 MeV energy range using 19 germanium detectors. The performance of the cryogenic system is nominal and allows to cool the 19 kg of germanium down to 85 K with a comfortable margin. The energy resolution of the whole camera is 2.5 keV at 1.1 MeV. This resolution degrades with time due to particle irradiation in space. We show that the annealing process allows the recovery of the initial performance. The anticoincidence shield works as expected, with a low threshold at 75 keV, reducing the GeD background by a factor of 20. The digital …
Multidetector Computed Tomography Angiography (MD-CTA) of Coronary Artery Bypass Grafts – Update 2017
2017
Coronary artery bypass grafting (CABG) is still an important therapeutic approach in the treatment especially of advanced coronary artery disease. In this study, we elucidate the current role of multidetector computed tomography angiography (MD-CTA) in imaging patients after CABG surgery.This study is based on recent reports in the literature (2007 - 2016) on imaging of CABG using 64-slice MD-CT scanners and beyond. We included 13 reports that compared ECG-gated MD-CTA with conventional invasive coronary angiography (ICA) as the reference standard for the assessment of graft patency and for the detection of 50 % stenoses. These studies had to provide absolute values for true-positive, true-…
A rare case of a coronary artery anomaly detected on multidetector computed tomography
2013
An anomalous aortic origin of the coronary artery arising from the opposite sinus with an interarterial course is a rare condition that is associated with a high risk of sudden cardiac death during or after strenuous exertion. We herein report the case of a 47-year-old woman presenting with chest pain, syncope and palpitations who presented with a rare coronary artery anomaly on multidetector computed tomography coronary artery (MDCT-CA) with prospective electrocardiogram (ECG) gating.
Determination of chromophore distribution in skin by spectral imaging
2012
Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.
New Trends in Detectors for Medical Imaging
2010
The improvement of medical imaging instrumentation is based both on the enhancement of the performance of the detectors employed in their construction and on the development of novel techniques and methods that allow full exploitation of the advantages of the new instrumentation.