Fusion Programme - ENEA - Fusione

Fusion Programmennα6 LIF6 LIF9 BeIntrinsic CVDB-doped CVDαIntrinsic CVDB-doped CVDTFig. 1.19 - Schematic of CVDdetector for detecting thermaland 14–MeV neutronsHPHTHPHT1.51.3R 2 =4.47×10 -2Ratio1.10.90.7Fig. 1.20 - Counting ratiobetween SCD and fissionchambers vs JET neutronyield/shot0.5Neutron yield5×10 14 1.05×10 16 2.05×10 16 3.05×10 16n + 6 Li → T + α + 4.8 MeVE T = 2.73 MeV; E α = 2.06 MeV .[1.63] M. Pillon et.al., Fusion Eng. Des. 82, 1174 (2007)Both detectors were tested (see also [1.63,1.64]) and a good correlation was found between the p-CVDand SCD measurements and those of the fission chambers. The ratio of the SCD/fission chambermeasurement vs the neutron yield showed good stability, i.e., over two orders of magnitude of variation inneutron yield (fig. 1.20).Since the goal of the SCD detector was to demonstrate its capability to simultaneously detect total and14–MeV neutrons, figure 1.21 reports the correlation between the SCD detector and one of the 14-MeVsilicon diode monitors used at JET (KM–7 diagnostic). Despite the poor statistics of the SCD due to itsthinness, the correlation is surprisingly good, well within the experimental error.Another important aspect is to compare the time-dependent behaviour with that recorded by the silicondiode. The example given in figure 1.22 was obtained by summing two shots. The capability of the SCDto measure simultaneously the DD and 14–MeV neutrons is clear in the figure.2007 Progress ReportArtificial diamonds for UV light detection. UV radiation coming from the plasma is measured at JETby using mult micro-channel plates with a 1D photodiode array. These types of monitors are suitable forJET plasma as the other radiation background (due to neutrons and gamma-rays) is not strong enough todowngrade their detection performance. It is very important to test a CVD diamond as a UV detector atJET because the monitors (especially themicro–channel plates) used at present are very28