A Two-Step Inverse Procedure for Outer Surface Defects Characterization from Ultrasonic BScan Images

In service inspections of French nuclear pressure water reactor (PWR) vessels are carried out automatically in complete immersion from the inside by means of ultrasonic focused probes working in the pulse-echo mode. Concern has been expressed about the capabilities of performing non destructive evaluation of Outer Surface Defects (OSD’s), i.e., defects located in the vicinity of the outer surface, in nuclear PWR vessels. The OSD’s are insonified by both a “direct” field that passes through the inner surface of the inspected component containing the defect and a “secondary” field reflected from its outer surface. Consequently, Bscan images containing the signature of such defects are complicated and their interpretation is a difficult task

An Inverse Method for Cracks Characterization from Ultrasonic Bscan Images

Concern has been expressed about the capabilities of performing non destructive evaluation (NDE) of flaws located near to the outer surface in nuclear pressurized water reactor (PWR) vessels. The ultrasonic examination of PWR is accomplished from the inside with ultrasonic focused transducers working in the pulse echo mode. By recording the echoes as a function of time, the Ascan representation may be obtained. Many ultrasonic flaw detectors used for NDE are based on the simple Ascan concept involving measuring a time interval called “time of flight”. By combining the Ascan concept with synchronized transducer scanning, one can produce Bscan images that are two dimensional descriptions of the flaw interaction with the ultrasonic field

A Two-Step Inverse Procedure for Outer Surface Defects Characterization from Ultrasonic BScan Images

In service inspections of French nuclear pressure water reactor (PWR) vessels are carried out automatically in complete immersion from the inside by means of ultrasonic focused probes working in the pulse-echo mode. Concern has been expressed about the capabilities of performing non destructive evaluation of Outer Surface Defects (OSD’s), i.e., defects located in the vicinity of the outer surface, in nuclear PWR vessels. The OSD’s are insonified by both a “direct” field that passes through the inner surface of the inspected component containing the defect and a “secondary” field reflected from its outer surface. Consequently, Bscan images containing the signature of such defects are complicated and their interpretation is a difficult task.</p

An Inverse Method for Cracks Characterization from Ultrasonic Bscan Images

Concern has been expressed about the capabilities of performing non destructive evaluation (NDE) of flaws located near to the outer surface in nuclear pressurized water reactor (PWR) vessels. The ultrasonic examination of PWR is accomplished from the inside with ultrasonic focused transducers working in the pulse echo mode. By recording the echoes as a function of time, the Ascan representation may be obtained. Many ultrasonic flaw detectors used for NDE are based on the simple Ascan concept involving measuring a time interval called “time of flight”. By combining the Ascan concept with synchronized transducer scanning, one can produce Bscan images that are two dimensional descriptions of the flaw interaction with the ultrasonic field.</p

Design and electronics commissioning of the physics prototype of a Si-W electromagnetic calorimeter for the International Linear Collider

The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the electromagnetic calorimeter, the current baseline choice is a high granularity sampling calorimeter with tungsten as absorber and silicon detectors as sensitive material. A ``physics prototype'' has been constructed, consisting of thirty sensitive layers. Each layer has an active area of 18 × 18 cm2 and a pad size of 1 × 1 cm2. The absorber thickness totals 24 radiation lengths. It has been exposed in 2006 and 2007 to electron and hadron beams at the DESY and CERN beam test facilities, using a wide range of beam energies and incidence angles. In this paper, the prototype and the data acquisition chain are described and a summary of the data taken in the 2006 beam tests is presented. The methods used to subtract the pedestals and calibrate the detector are detailed. The signal-over-noise ratio has been measured at 7.63±0.01. Some electronics features have been observed; these lead to coherent noise and crosstalk between pads, and also crosstalk between sensitive and passive areas. The performance achieved in terms of uniformity and stability is presented

CALICE Report to the Calorimeter R&D Review Panel

The report describes the status of the calorimeter R&D for ILC detector performed in the CALICE collaboration. This status has been presented to the review panel at the LCWS07 workshop at DESY in June 2007