Estudo Geralhttps://estudogeral.sib.uc.ptThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sat, 30 May 2020 07:00:50 GMT2020-05-30T07:00:50Z5021Transient behaviour and rate effects in resistive detectorshttp://hdl.handle.net/10316/4561Title: Transient behaviour and rate effects in resistive detectors
Authors: Fraga, M. M.; Marques, R. Ferreira; Ivaniouchenkov, Y.; Lima, E. P. de; Neves, F.; Policarpo, A. J. P. L.; C. Bueno, Carmen; Gonçalves, Josemary A. C.; Santos, M. Damy de S.; Costa, L.; Mendiratta, S.; Monteiro, J. H.
Abstract: The dependence of the detection efficiency (or charge gain) of a resistive detector on the counting rate has been considered by several authors. The influence of the resistivity of the electrodes, the counter geometry and the gas mixture composition have also been studied. Most of those measurements assume a stationary regime. In the present work we report on studies of the transient behaviour of detectors with a resistive cathode for various counting rates, charge gains and detector geometries. We show that in some cases the time-decay curves can be fitted by a single exponential plus a constant term, while in others (higher charge gains or higher counting rates) a sum of two or even three exponentials plus the constant term is needed to fit the experimental data. A study of the electric properties of the dielectrics used is also presented and a comparison is made between these results and the data obtained under irradiation conditions.
Thu, 01 Jan 1998 00:00:00 GMThttp://hdl.handle.net/10316/45611998-01-01T00:00:00ZRate effects in a proportional counter with resistive cathodehttp://hdl.handle.net/10316/4568Title: Rate effects in a proportional counter with resistive cathode
Authors: Bueno, Carmen C.; Fraga, M. M.; Gonçalves, Josemary A. C.; Marques, R. Ferreira; Policarpo, A. J. P. L.; Santos, M. Damy de S.
Abstract: In this work, the rate effects associated with the gain of detectors with resistive electrodes are considered. To study these effects it was decided to use the classical proportional counter geometry, with a cylindrical glass tube as the cathode, rather than parallel plate devices. Indeed, the generality of the information obtained is not affected and the cylindrical proportional counter geometry has several advantages to gather detailed experimental data and to compare it with simple electric field calculations. A self-consistent set of data is presented for the effects of counting rate from a few tens of Hz up to several hundreds of Hz, using several gas mixtures, different anode wires, cathode radii and thickness of the resistive electrodes. Although a few sources of systematic errors can be identified, all the observed experimental data can be quantitatively explained. Indeed, the measured gas amplification, from a few tens up to ~5×104 and for the range of counting rates quoted above, depends only on the local electric field as it should be expected. These results are directly relevant to approach the problem of counting efficiency in resistive plate chambers.
Thu, 01 Jan 1998 00:00:00 GMThttp://hdl.handle.net/10316/45681998-01-01T00:00:00Z