The 207Bi PHS (the distribution of the events as a function of their pulse height Q T ) measured with CNS. The Compton edges of the 207Bi γ rays and the LED peak have been fitted for assessing the performance of the BC501A liquid scintillating detector of the CNS.
(a) The CNS installed at AUG in front of the 2-m long neutron collimator obtained in the concrete wall. (b) Schematics of the CNS line of sight from above. The CNS is viewing the plasma radially in the tokamak equatorial plane at a distance of about 11 m from the plasma center through a pre-collimator and a collimator.
Count rates as a function of the DPSD acquisition time for the total, neutron and γ events measured by the CNS in AUG discharge 230 56. On the top, the evolution of the average LED pulse area during the discharge is shown.
Same as in Fig. 3 but for AUG discharge 230 69. The average LED pulse area follows exactly the count rate variation since the magnetic effects on the PMT are suppressed by the external μ-metal shielding.
Examples of pulse shapes recorded in discharge 241 51 with their corresponding number as recorded in the data set. Information is given on the DPSD acquisition trigger threshold at 10 mV. For pulse 583 818, the regions of interests for n-γ discrimination, namely, pre-trigger and gates S, L, and T (i.e., the pulse length) are shown.
Frequency distributions of the uncertainties Uo associated with the offset value calculated considering a number of pre-trigger samples No = [3, 6]. No* = 5 samples is the optimal number of samples for the offset reduction of the data because of its lowest average uncertainty value of 5 a.u..
Examples of normalized Q S/Q L distributions relative to different S-L gate combinations. The peak on the left-hand side corresponds to neutron events while the one on the right to γ’s. The maximum FOM value of 1.38 corresponds to S = 4 samples and L = 15 samples.
Contour plot of the radiation events recorded in AUG discharge 241 51. The pulse shapes were offset reduced and LED corrected and analyzed using the optimal gates S = 4 samples and L = 15 samples.
PHS Q T of total, neutron, γ and LED events. The LED events are peaked about the reference LED pulse area after the PHS has been corrected.
Comparison of count rates measured by the CNS with respect to the 100 ms time averaged AUG neutron yield (divided by 109) during AUG discharge 24151.
Main parameters of discharge 241 51 at AUG.
Summary of the results the CNS obtained during AUG discharge 24151 in terms of events and count rates for each type of event (see Fig. 10 ).
Article metrics loading...
Full text loading...