A method is presented for restoring the performance of gas discharge detectors wherein a spontaneous self-sustaining current, i.e., Malter effect, occurs. A successful practical implementation of the ...method is demonstrated by the example of recovery of operability for multiwire proportional chambers used in the muon detector of the LHCb experiment carried out at the Large Hadron Collider. Four proportional chambers wherein Malter currents regularly occur during the experiment were subjected to high-voltage discharge training in the working gas mixture of 40% Ar + 55% CO
2
+ 5% CF
4
with 2% of oxygen added. It is shown that, with addition of oxygen, the recovery of the proportional chambers occurs tens of times faster in compare to the training in the working gas mixture. The reconstructed chambers were installed in the LHCb muon detector and have been working in a collider beam experiment for more than two years already.
The new results of cathode surface degradation in muon proportional chambers of CMS after a long-term irradiation with a
90
Sr β-source are presented. The data of the complex analysis of the copper ...foil samples from the cathode are shown. The AFM method revealed the general radiation damage of the copper surface and the dynamics of its change. It is clearly demonstrated that the revealed development of the radiation erosion on the cathode is a result of electron irradiation. Moreover, the nature of erosion and level of the destruction of copper are associated with irradiation intensity. The study of the elemental and phase composition together with the data of structural analysis allowed us to single out the stages of the radiation aging of the copper surface on the cathodes and consider the processes which are at the basis of them.
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A two-dimensional thermal-neutron detector developed for a small-angle diffractometer by the Petersburg Nuclear Physics Institute is described. The detector, with a sensitive area of 600 × 600 mm
2
..., is based on a multiwire proportional chamber. A gas mixture containing
3
He is the neutron converter. A new technology for manufacturing electrodes has been developed and used to increase both the gas purity and the lifetime of the detector without refilling its working volume under the experimental conditions. Data acquisition is carried out by the readout system based on the method of cathode-strip data readout to an
LC
delay line, which is located inside the detector. The detector is operable in a vacuum owing to its design.
A method of noninvasive recovery of gas-discharge detectors degraded due to operation in intense radiation fields is described. The plasma-chemical reactions are the basis of the presented ...techniques; these reactions take place during the detector training in a gas discharge of special recovering gas mixtures. The results of recovery of operating parameters for proportional chambers and counters are presented.
