Electromagnetic showers in a strong magnetic field

We present the results concerning the main shower characteristics in a strong magnetic field obtained through shower simulation. The processes of magnetic bremsstrahlung and pair production were taken into account for values of the parameter $\chi \gg 1$. We compare our simulation results with a recently developed cascade theory in a strong magnetic field.Comment: 11 pages, 9 eps figures, LaTex2e, Iopart.cls, Iopart12.clo, Iopams.st

Muon Track Matching

For most physical processes the tracks observed in the muon stations must be matched with the corresponding tracks in the inner tracker, the external muon system providing muon identification and triggering but the tracker points giving the precise momentum measurement at lower momenta. For high momenta the momentum resolution is much improved by the interconnection of inner and outer measurements. The matching of outer and inner measurements is more delicate in case of muons embedded in jets. A study of the matching procedure was carried out using samples of (b, anti b) jets at high Pt, requiring (b, anti b) -> mu decays.For most physical processes the tracks observed in the muon stations must be matched with the corresponding tracks in the inner tracker, the external muon system providing muon identification and triggering but the tracker points giving the precise momentum measurement at lower momenta. For high momenta the momentum resolution is much improved by the interconnection of inner and outer measurements. The matching of outer and inner measurements is more delicate in case of muons embedded in jets. A study of the matching procedure was carried out using samples of (b, anti b) jets at high Pt, requiring (b, anti b) -> mu decays

The nature of the highest energy cosmic rays

Ultra high energy gamma rays produce electron--positron pairs in interactions on the geomagnetic field. The pair electrons suffer magnetic bremsstrahlung and the energy of the primary gamma ray is shared by a bunch of lower energy secondaries. These processes reflect the structure of the geomagnetic field and cause experimentally observable effects. The study of these effects with future giant air shower arrays can identify the nature of the highest energy cosmic rays as either gamma-rays or nuclei.Comment: 15 pages of RevTeX plus 6 postscript figures, tarred, gzipped and uuencoded. Subm. to Physical Review

Inspection of riveted connections by free oscillation technique.Inspection of riveted connections for “riveted wheel blades” at the production stage

© 2016, International Journal of Pharmacy and Technology. All rights reserved.The article presents the results of the production testing of the diagnostic system for quality instrumentation inspection for riveted connections with free oscillations technique. The test program consisted of four stages. In the first stage we selected guide cases which were new and spent a part of their resource having characteristic defects of riveted connections. In the second stage we formed reference spectra of inspected connections. At the third stage we established the relation between the numerical value of the Spearman correlation coefficient and the shear force of a blade. In the fourth stage, all tested connections were sent to additional riveting. Following the inspection with the free oscillations technique and on shear force, we have determined that shear force momentis constant and defective riveted connections were absent upon established rejectable quality levelis 0.75 of Spearman correlation coefficient. According to the tests results it is recommended to set the rejectable quality limit with regard to evaluation of Spearman correlation coefficient at 0.75that corresponds to 10 N m shear force moment of a blade. The developed inspection technique allows grading of riveted connection as “defected” and “fit” without unproductive manual inspection. Application of the technique allows quickly and with a high degree of certainty to reveal defective riveted connections in GTE guide cases what increases engine reliability and allows saving time and costs to determine the technical condition of gas turbine plants. The instrumental technique is implemented in the non-destructive inspection complex where the positioning of the inspected product, recording, analysis of vibro-acoustic signal and making conclusion on the conditions of a product is performed automatically, without operator intervention, that eliminates subjectivity in the decision-making

Testing method for riveted connections using the free oscillation technique. Numerical simulation

© 2016, International Journal of Pharmacy and Technology. All rights reserved.The article presents the results of studies on the development of methods and diagnostic system for instrumental quality control of riveted connections using the automated free oscillation technique. Based on the analysis of the known non-destructive testing methods of a riveted connection, it has been concluded that application of the free oscillation technique is very promising for quality control in the manufacture and repair of the gas turbine engine’s stators in order to identify different types of defects. The free oscillation technique (FOT) relies on excitation of freely damped elastic oscillations in a test object or part thereof and analysis of parameters of these oscillations. The FOT informative parameter is the change in the spectrum of free elastic oscillations of test objects. In order to accelerate the development of certain testing methods, the numerical experiments were carried out to determine the natural frequencies of suitable and defective riveted connections. Following the numerical simulation results, the optimal method of attaching a test disc to blades and informative frequency ranges were determined; they indicate that some defects of riveted connections are available

Control for riveted connections by free oscillation technique. Hardware and software system. Evaluation of measurement error

© 2016, International Journal of Pharmacy and Technology. All rights reserved.The paper presents the results of studies on the development of techniques and diagnostic suite for instrumentation control for quality of riveted joints by the free oscillation technique in automatic mode. The suite consists of a recording system and a signal processing system. The registration system includes a device for positioning the inspected articles. Excitation of oscillations in an inspected article is carried out with a calibrated strike. Signal processing system is composed of a hexadecimal analog-to-digit converter and a digital computer. Acoustic signals of vane vibrations are recorded on the hard disk, and their processing is performed with a software package. The description of DetectFault software created in LabVIEW environment. The software controls the movement of a guide wheel and a striker bar, ensures registration and transformation of signals from analog to digital form with the set number of samples and sampling interval value. The control algorithm is described. Acceptance or rejection of a riveted connection is made depending on the results of comparison of a reference and the current spectrum for the Spearman correlation coefficient and the rejectable level (higher - passed, below - rejected). To classify a riveted connection as “fit” or “defective”, an approach should be used that is specific to procedures on rejection of anomalies by a confidence interval. A robust weighting algorithm is used when forming the reference spectrum. The error estimation of the measurement results was carried out. The results of reproducibility of the data during the monitoring of riveted joints

Resistive Plate Chambers with Gd-coated electrodes as thermal neutron detectors

Abstract Resistive Plate Chambers (RPCs) are wide spread, cheap, easy-to-build and large size detectors, used mainly to reveal ionising particles in high-energy physics experiments. Here a technique, consisting in coating the inner surface of the bakelite electrodes with a mixture of linseed oil and Gd 2 O 3 is reported. This allows to make RPCs sensitive also to thermal neutrons, making them suitable to be employed for industrial, medical or de-mining applications. Thermal neutron-sensitive RPCs can be operated at atmospheric pressure, are lightweighted, have low γ -ray sensitivity and are easy to handle even when large areas have to be covered. This paper reports the results of the first test of this detector, performed at the Geel Linear Accelerator (GELINA) in Belgium