In a previous work it bas been pointed out that a CCD readout systcrn associated to a microstructure based gaseous detector (microstrip, microgap, GEM, ctc.) can be used for non destructive testing OS these detectors. The choicc of the gas mixture is an important issue, in so far as its emission spectrum should overlap efficiently the scnsitivity region of the CCD (400-1100 nm). In the present work we repott on a systematic study for several gas mixtures which includes mcasuremenls of the total light yields as a function of the electric field and of the spectrometric distribution of the light emitted, in the wavelength region between 250 and 930 nm. Results are presented for pure argon and argon and xenon based gas mixtures. A comparison is made between the results obtained with the CCD coupled to a GEM detector and with a gaseous scintillation proportional counter.
a b s t r a c tThe presence of secondary processes in electron multiplication under high uniform electric fields at atmospheric pressure in pure isobutane was investigated. The experimental setup consists of a Resistive Plate Chamber-like cell with the anode made of a high resistivity glass (2 Â 10 12 O cm) and a metallic cathode, on which photoelectrons are produced by the incidence of a pulsed laser beam. In particular, the dependence of the first Townsend coefficient (a) on the repetition rate and the intensity of the UV laser pulses was studied. The E=N range considered spanned from % 145 to % 200 Td. The a coefficient was determined by measuring both the primary ionization and the avalanche currents with the help of an electrometer, directly connected to the cathode. Of all the investigated secondary effects, only the ohmic drop across the resistive glass has been found to be non-negligible in the present experimental conditions and has been corrected for. The obtained values are compared with Magboltz simulation results and presented in tabular form.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.