Abstract The propagation of light flashes in pipes is experimentally studied by light emitting di... more Abstract The propagation of light flashes in pipes is experimentally studied by light emitting diodes and by the NE 104 plastic scintillator. A theoretical model based on geometrical optics is proposed. The experimental scintillation flash-shapes obtained by the single-photon technique are compared with those theoretically calculated.
The propagation of a LED light pulse entering a rectangular light pipe under different angles is ... more The propagation of a LED light pulse entering a rectangular light pipe under different angles is studied by the single-photon counting technique. A comparison with the theoretical predictions based on geometrical optics is reported.
The energy resolution of a surface-barrier detector, thermoelectrically ; cooled, has been measur... more The energy resolution of a surface-barrier detector, thermoelectrically ; cooled, has been measured from 20 deg C to --30 deg C. Different thermic screens ; have been used in order to evidence the effect of thermic gradients inside the ; detector. (auth);
ABSTRACT It has been shown that cavitation zone generated by the high intensity focused ultrasoun... more ABSTRACT It has been shown that cavitation zone generated by the high intensity focused ultrasound (HIFU) passes through different stages of evolution with either increasing pulse duration, decreasing pulse period or increasing driving voltage of pulsed ultrasound. In the first stage sonoluminescence (SL) is absent. Here sound absorption is weak in the cavitation zone and the hydrophone output is nearly constant if the transducer voltage is constant. The second stage corresponds to the onset of sonoluminescence and the smooth increase of its intensity. In the third stage, the sonoluminescence intensity increases in a sudden manner, accompanied by a synchronous rise of the ultrasound absorption in the cavitation zone. The sonoluminescence intensity reaches a maximum value and then decreases while ultrasound absorption increases smoothly upon further cavitation zone evolution. Two cavitation thresholds separate these stages: first is related to the SL appearance and the second-to the sudden increase of the SL intensity.
The propagation of hght pulses in sclntdlators and light p~pes has been theoretically simulated T... more The propagation of hght pulses in sclntdlators and light p~pes has been theoretically simulated The t~mlng and locahzatlon errors due to a non-constant effective pulse propagation-velocity are evaluated
... The amplitude A ,(0,t) of light diffracted at the angle 0 from the nth grating slit, placed i... more ... The amplitude A ,(0,t) of light diffracted at the angle 0 from the nth grating slit, placed in the positive x direction, is10 np+ja A n(0,t) = AO exp[ju(Lpo-ct)] J nP-1a exp(julx) Xexp{j _ vi sin[i(kx-Wj1)] i=1 ... 1np+1a A n(0,1) =A o exp~j11(L)UO-c1) J np-11 exp(julx) ...
... Horrocks, Applications f liquid scintillation counting (Academic Press, New York and London, ... more ... Horrocks, Applications f liquid scintillation counting (Academic Press, New York and London, 1974) 3) WF Libby, Phil Trans Roy Soc Lond A269 (1970a) 1 4) WF Libby, Radiocarbon variation and absolute chronology (Ed IU Olsson, Almqvist and Wiksell, Stockholm, 1970b) p ...
We present some unpublished experimental results concerning the absorption of negative pions on 4... more We present some unpublished experimental results concerning the absorption of negative pions on 4He, 6Li, 9Be and 12C; reactions of the type (π-,np) and (π-,nd) are investigated for 6Li, 9Be and 12C while on 4He the three reactions, π + 4He = t + n, π- + 4He = p 3n are analyzed by the study of the energy spectra of the neutrons, protons and deutrons. The energy of the correlated and uncorrelated neutrons was determined by a time-of-flight technique; the energy and the discrimination of protons and deuterons was done by a combined time-of-flight and range telescope method.
The timing properties of plastic scintillators and photomultipliers are investigated, in view of ... more The timing properties of plastic scintillators and photomultipliers are investigated, in view of the more recent technology and electronics available at present. The intrinsic limits of the techniques are discussed.
The cavitation thresholds of subharmonic emission and of sonoluminescence in water have been meas... more The cavitation thresholds of subharmonic emission and of sonoluminescence in water have been measured in a focused ultrasound beam by two different methods: (1) by increasing the transducer voltage at different rates; (2) by keeping a chosen constant transducer voltage and waiting for the appearance of the subharmonic or of the sonoluminescence. The thresholds increase with increasing the rate of voltage increase. The waiting time diminishes with the increase of the chosen threshold voltage.
... 2g 2g 2z v,=~ ,-L~' u=~-, b=~--, and introduce the expression of F(x, t) in (1), A(O... more ... 2g 2g 2z v,=~ ,-L~' u=~-, b=~--, and introduce the expression of F(x, t) in (1), A(O, t) is given by (3) A(O, t) = a exp [ju(I'~ -- et) xp [julx] [I exp [iv, sin [i(bx-- wJ)]]dx. i=l ... (4) A(O, *) -- a exp [ju(L~ -- et)]- +~ fe += 9 xp [julx] ~J,,(vl)J,,(v=) ... exp [j(r~ + 2r2 + ...)bx--oJ,O]dx-Txrl. .. =- ...
Abstract The propagation of light flashes in pipes is experimentally studied by light emitting di... more Abstract The propagation of light flashes in pipes is experimentally studied by light emitting diodes and by the NE 104 plastic scintillator. A theoretical model based on geometrical optics is proposed. The experimental scintillation flash-shapes obtained by the single-photon technique are compared with those theoretically calculated.
The propagation of a LED light pulse entering a rectangular light pipe under different angles is ... more The propagation of a LED light pulse entering a rectangular light pipe under different angles is studied by the single-photon counting technique. A comparison with the theoretical predictions based on geometrical optics is reported.
The energy resolution of a surface-barrier detector, thermoelectrically ; cooled, has been measur... more The energy resolution of a surface-barrier detector, thermoelectrically ; cooled, has been measured from 20 deg C to --30 deg C. Different thermic screens ; have been used in order to evidence the effect of thermic gradients inside the ; detector. (auth);
ABSTRACT It has been shown that cavitation zone generated by the high intensity focused ultrasoun... more ABSTRACT It has been shown that cavitation zone generated by the high intensity focused ultrasound (HIFU) passes through different stages of evolution with either increasing pulse duration, decreasing pulse period or increasing driving voltage of pulsed ultrasound. In the first stage sonoluminescence (SL) is absent. Here sound absorption is weak in the cavitation zone and the hydrophone output is nearly constant if the transducer voltage is constant. The second stage corresponds to the onset of sonoluminescence and the smooth increase of its intensity. In the third stage, the sonoluminescence intensity increases in a sudden manner, accompanied by a synchronous rise of the ultrasound absorption in the cavitation zone. The sonoluminescence intensity reaches a maximum value and then decreases while ultrasound absorption increases smoothly upon further cavitation zone evolution. Two cavitation thresholds separate these stages: first is related to the SL appearance and the second-to the sudden increase of the SL intensity.
The propagation of hght pulses in sclntdlators and light p~pes has been theoretically simulated T... more The propagation of hght pulses in sclntdlators and light p~pes has been theoretically simulated The t~mlng and locahzatlon errors due to a non-constant effective pulse propagation-velocity are evaluated
... The amplitude A ,(0,t) of light diffracted at the angle 0 from the nth grating slit, placed i... more ... The amplitude A ,(0,t) of light diffracted at the angle 0 from the nth grating slit, placed in the positive x direction, is10 np+ja A n(0,t) = AO exp[ju(Lpo-ct)] J nP-1a exp(julx) Xexp{j _ vi sin[i(kx-Wj1)] i=1 ... 1np+1a A n(0,1) =A o exp~j11(L)UO-c1) J np-11 exp(julx) ...
... Horrocks, Applications f liquid scintillation counting (Academic Press, New York and London, ... more ... Horrocks, Applications f liquid scintillation counting (Academic Press, New York and London, 1974) 3) WF Libby, Phil Trans Roy Soc Lond A269 (1970a) 1 4) WF Libby, Radiocarbon variation and absolute chronology (Ed IU Olsson, Almqvist and Wiksell, Stockholm, 1970b) p ...
We present some unpublished experimental results concerning the absorption of negative pions on 4... more We present some unpublished experimental results concerning the absorption of negative pions on 4He, 6Li, 9Be and 12C; reactions of the type (π-,np) and (π-,nd) are investigated for 6Li, 9Be and 12C while on 4He the three reactions, π + 4He = t + n, π- + 4He = p 3n are analyzed by the study of the energy spectra of the neutrons, protons and deutrons. The energy of the correlated and uncorrelated neutrons was determined by a time-of-flight technique; the energy and the discrimination of protons and deuterons was done by a combined time-of-flight and range telescope method.
The timing properties of plastic scintillators and photomultipliers are investigated, in view of ... more The timing properties of plastic scintillators and photomultipliers are investigated, in view of the more recent technology and electronics available at present. The intrinsic limits of the techniques are discussed.
The cavitation thresholds of subharmonic emission and of sonoluminescence in water have been meas... more The cavitation thresholds of subharmonic emission and of sonoluminescence in water have been measured in a focused ultrasound beam by two different methods: (1) by increasing the transducer voltage at different rates; (2) by keeping a chosen constant transducer voltage and waiting for the appearance of the subharmonic or of the sonoluminescence. The thresholds increase with increasing the rate of voltage increase. The waiting time diminishes with the increase of the chosen threshold voltage.
... 2g 2g 2z v,=~ ,-L~' u=~-, b=~--, and introduce the expression of F(x, t) in (1), A(O... more ... 2g 2g 2z v,=~ ,-L~' u=~-, b=~--, and introduce the expression of F(x, t) in (1), A(O, t) is given by (3) A(O, t) = a exp [ju(I'~ -- et) xp [julx] [I exp [iv, sin [i(bx-- wJ)]]dx. i=l ... (4) A(O, *) -- a exp [ju(L~ -- et)]- +~ fe += 9 xp [julx] ~J,,(vl)J,,(v=) ... exp [j(r~ + 2r2 + ...)bx--oJ,O]dx-Txrl. .. =- ...
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