Uncovering the kiloparsec-scale stellar ring of NGC5128

We reveal the stellar light emerging from the kiloparsec-scale, ring-like structure of the NGC5128 (Centaurus A) galaxy in unprecedented detail. We use arcsecond-scale resolution near infrared images to create a "dust-free" view of the central region of the galaxy, which we then use to quantify the shape of the revealed structure. At the resolution of the data, the structure contains several hundreds of discreet, point-like or slightly elongated sources. Typical extinction corrected surface brightness of the structure is K_S = 16.5 mag/arcsec^2, and we estimate the total near infrared luminosity of the structure to be M = -21 mag. We use diffraction limited (FWHM resolution of ~ 0.1", or 1.6 pc) near infrared data taken with the NACO instrument on VLT to show that the structure decomposes into thousands of separate, mostly point-like sources. According to the tentative photometry, the most luminous sources have M_K = -12 mag, naming them red supergiants or relatively low-mass star clusters. We also discuss the large-scale geometry implied by the reddening signatures of dust in our near infrared images.Comment: 5 pages, 4 figures, accepted for publication in A&A Letters. A version with high resolution images can be downloaded from http://www.helsinki.fi/~jtkainul/CenALette

High Resolution RPC's for Large TOF Systems

Here we report on a particular type of RPC that presents up to 99% efficiency for minimum ionizing particles and a very sharp time resolution, below 50 ps sigma in the most optimized conditions. Our 9 cm2 cells, made with glass and metal electrodes that form accurately spaced gaps of a few hundred micrometers, are operated at atmospheric pressure in non-flammable gases and can be economically produced in large quantities, opening perspectives for the construction of large area time of flight systems.Comment: 10 pages, 8 figure

A large area timing RPC prototype for ion collisions in the HADES spectrometer

We present a resistive plate chamber (RPC) prototype for time-of-flight measurements over large areas and at high occupancies, minimizing the inter-channel cross-talk.http://www.sciencedirect.com/science/article/B6TJM-4D75GPD-9/1/a6fe40c114a867a0f98e2fec0f13350

A four gap glass RPC time-of-flight array with 90 ps time resolution

In this work we describe the performance of a prototype developped in the context of the ALICE team-of-flight R&D system. The detector module consists of a 32-channel array of 3 x 3 cm2 glass-RPC cells, each of which has four accurately spaced gaps of 0.3. mm thickness arranged as a pair of double-gap resistive plate chambers. Operated with a non-flammable gas mixture at atmospheric pressure, the system achieved a time resolution of 90 ps at 90% efficiency with good uniformity and moderate crosstalk. This result shows the feasibility of large-area, high resolution time-of-flight systems based on RPCs at affordable cost

Mechanical construction and installation of the ATLAS tile calorimeter

This paper summarises the mechanical construction andinstallation of the Tile Calorimeter for the ATLASexperiment at the Large Hadron Collider in CERN, Switzerland. The TileCalorimeter is a sampling calorimeter using scintillator as the sensitivedetector and steel as the absorber and covers the central region of the ATLASexperiment up to pseudorapidities ±1.7. The mechanical construction ofthe Tile Calorimeter occurred over a periodof about 10 years beginning in 1995 with the completionof the Technical Design Report and ending in 2006 with the installationof the final module in the ATLAS cavern. Duringthis period approximately 2600 metric tons of steel were transformedinto a laminated structure to form the absorber of the sampling calorimeter.Following instrumentation and testing, which is described elsewhere, themodules were installed in the ATLAS cavern with a remarkable accuracy fora structure of this size and weight.Peer Reviewe

A novel route to optimize placement equipment kinematics by coupling capacitive accelerometers

Machine end-effector kinematic analysis is critical to optimizing transporting components where inertial forces are the main loads. While displacements may be measured with relatively high accuracy in transportation equipment motors, the inertial forces in the transported components are seldom optimized. This is especially relevant in electronic component placement systems, where the components have a wide range of configurations (i.e., geometry and mass) and the deployment dimensional/geometric tolerances are remarkably good. The optimization of these systems requires the monitoring of the real position of the accelerometers relative to the measurement point of interest with sufficient accuracy that allows the assembly position to be predicted instantaneously. This study shows a novel method to calibrate this equipment using triaxial accelerometers on a surface mount machine to measure the end-effector accelerations and velocities in its planar motion. The dynamic equations of the system and the method for integration are presented to address the uncertainty on the exact position of the accelerometer sensors relative to the measuring point of interest exist and allow the position correction to optimize response and accuracy.European Structural and Investment Funds in the FEDER component through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project no. 39479; Funding Reference: POCI-01-0247-FEDER-39479]

Paediatric phantom dose study using digital radiography with variation of exposure parameters and filtration

Paediatric digital radiography remains a challenge for many radiographers. The subsequent need for focused paediatric care is outlined by ‘The Image Gently Campaign’, which reports a lack of both expertise and educational resources surrounding this area. This requirement is reinforced by The International Commission on Radiological Protection (ICRP), which identifies a need for both optimisation and consistency in digital paediatric imaging. Although a considerable proportion of recent research surrounds paediatric diagnostic imaging, Jones et. al highlights an absence of literature regarding optimisation in paediatric extremity imaging.This is of particular importance when considering paediatric patients who, due to their additional life expectancy and increased tissue radio-sensitivity, are considerably more sensitive to the detrimental effects of ionising radiation. Although the radiation dose received for diagnostic purposes is low, it is pertinent that each exposure be minimised due to the cumulative nature of radiation. The question to be addressed through our study is as follows; using a paediatric phantom with multiple bone fractures, could the variation of exposure parameters and filtration in digital radiography achieve a reduction in dose without substantially affecting image quality? This study aims to evaluate the variation of exposure parameters and filtration in image quality and dose in a paediatric phantom study using a digital radiography (DR) wireless detector.info:eu-repo/semantics/publishedVersio