Калибровка нейтронных счетчиков токамака Глобус-М2

The paper discusses the results of the calibration of two corona neutron counters used to measure the total neutron yield from the plasma of the Globus-M2 tokamak. The calibration was carried out in the experimental hall of the Globus-M2 facility using an AmBe source. During the calibration, the source moved uniformly around the central solenoid in the equatorial plane of the vacuum chamber, and one of the detectors was gradually moved away from the tokamak along a line with a constant toroidal angle. The values of the calibration coefficient obtained depending on the distance of the detector from the tokamak axis are presented. The calibration technique made it possible to separate in the detector signal the contributions from the direct neutron flux emitted by the plasma and from the flux of neutrons scattered on the elements of the experimental hall.

Robustness study of bandpass NGD behavior of ring-stub microstrip circuit under temperature variation

This paper explores an original study of bandpass (BP) negative group delay (NGD) robustness applied to the ring-stub passive circuit. The proof of concept (PoC) circuit is constituted by a ring associated with the open-end stub implemented in microstrip technology. An innovative experimental setup of a temperature room containing the NGD PoC connected to a vector network analyzer is described. Then, the electrothermal data of S-parameters are measured by varying the ambient or room temperature range from 20 to 60°C, i.e. 40°C maximal variation. The empirical results of the group delay (GD), transmission and reflection coefficient mappings versus the couple (temperature, frequency) highlight how the temperature affects the BP NGD responses. An innovative electrothermal calibration technique by taking into account the interconnection cable influence is developed. The electrothermal robustness analysis is carried out by variations of the NGD center frequency, cut-off frequencies and value in function of the temperature.

Applied TRL Calibration Technique Using ABCD Matrices for Bended Access Ports

Calibrating network analyzer is still an issue for bended access port devices (devices with access). Bended accesses can give additional errors which are taken into account by using a new design standards of Vector Network Analyzer (VNA) calibration. This Thru-Reflect-Line calibration technique is computed from ABCD parameters that easily allow to remove the bended port effects. This approach is based on the assumption that the Vector Network Analyzer error boxes can be considered as passive system. Furthermore, the method can be applied for de-embedding devices with bended accesses. This calibration and de-embedding technique could be applied, for example, to a coplanar circulator or a power divider measurement which have access lines at 120° from each other.

Camera Calibration Using Catenary

In this work, we introduce a novel calibration technique based on a hanging chain curve replacing the checkerboard-based methods. It is a known physical phenomenon that a hanging chain or a flexible rope under gravity can be modeled by a special curve called catenary. Therefore, instead of the commonly-used planar calibrator, we propose using multiple shots of a catenary-shaped chain for calibration. This approach can solve the out-of-focus problem which is faced in checkerboard calibration methods when the size of the board is not large enough. Although enlarging a planar calibrator increases the manufacturing time and cost, a simple label chain can create large planar areas as precise as a rigid checkerboard, is easily foldable and transportable. We compare the results of our proposed approach against the widely used checkerboardbased calibration as well as the state-of-the-art calibration methods and show that catenary-based calibration is much more accurate than checkerboard-based calibration by a very large margin and is also very competitive among the other approaches.<br>