5.2 Data on anisotropy measurements of neutron emission using PF-6 device in the presence of the simulator of a section of a toroidal chamber of a mainstream fusion facility (the PF-1000U chamber)

The process of measurements of neutron fluxes in different directions is about the same as above for the case of the empty hall with a bit different distances from the neutron source to the Faraday cages No. 1 and No. 2 (they were recalculated). Results of these measurements and their treatment including construction of an anisotropy graph are depicted in Table 7 (together with the "clean-room" data for comparison) and in Figure 21 presented here for demonstrativeness. This picture is a polar chart analogous to that of Figure 20. It presents quite perceptibly both data on anisotropy obtained in a "clean" room conditions (shown by green color) and in a hall with a simulator of a tokamak chamber section (red color). This large-scale object is represented here by a discharge chamber of the PF-1000U installation (see Figure 14). In particular, one may clearly see a strong influence of the PF-6 chamber supplement (Figure 16) and PF-1000U chamber electrodes (Figure 14) produced upon the neutron flux densities under the measurements. Indeed, it becomes apparent in the position V: here between the SAC-2 and the source, the flat part of the supplement (2 cm of stainless steel) is situated; it is even more evident for the locations VI and VII where the SAC-2 records the neutron flux passing through the supplement's protrusion (here we have 4 cm of SS) and through the PF-1000U chamber electrodes. At the same time, just contrary—in the locations of the SAC-2 numbers III, II, I, and IV, the data obtained in this experiment feebly differ from the readings attained in the empty room (positions 1, 2, 3, 4, 5 of the SAC-2).

For the position III, which is close to the location 2 in the empty-room conditions, the same peculiarity (a small dip) in the neutron flux density is observed. It is a consequence of the presence of the same object as in the above-presented


#### Table 7.

Data on anisotropy of the neutron yield in the hall with the simulator.

Taxonomy of Big Nuclear Fusion Chambers Provided by Means of Nanosecond Neutron Pulses DOI: http://dx.doi.org/10.5772/intechopen.89364

#### Figure 21.

Polar diagram of neutron yield measured for the PF-6 device in the conditions with a simulator of a section of a tokamak chamber by means of the discharge chamber of the PF-1000U facility; it is shown by red color (the green color diagram refers to the "empty-room" condition).

"clean-room" conditions (an influence upon the neutron radiation produced by the cables bundle). A noticeable influence of the PF-1000U chamber may be seen in the location V (in this very direction the scatterers/absorbers obstacles are cables of the PF-1000U facility—see Figure 14). In the locations VI and VII where the SAC-2 is blocked by a thick SS supplement of the PF-6 chamber itself and by the central part of the chamber of PF-1000U device (electrodes), the SAC-2 readings were dramatically decreased.

This chart is again an image projection of a polar diagram presenting both data on anisotropy obtained in a "clean" room conditions (shown by green color) and with a simulator (red color) in the plane of SACs that are 70 cm higher than the level with Z axes of PF-6 and PF-1000U facilities and the detectors PMT + Ss. This is a vertical projection of the neutron flux angular distribution to the horizontal plane containing Z axes of both devices as it is shown in Figures 13 and 14. After this session, we came to processing of data obtained with fast probes (PMT + Ss).
