High-voltage power supply with improved thermostability for Xenon gamma-ray spectrometer

In this article the high voltage power supply for xenon spectrometer is described. Result of time simulation for output voltage at different temperatures was shown. The experimental data is confirming results of the time simulations. The experimental data showed breadboard model provides a stability of voltage better than 1% of the generated voltage at different temperatures


Introduction
The development of a gamma spectrometer "Signal", based on the Xenon gamma ray spectrometer (HPXe spectrometer) is carrying out as part of the experiment "Interheliozond". Since the experiment will be carried out in hard environment it is required to increase the reliability and stability of the HPXe spectrometer [1]. To increase thermostability of HPXe spectrometer is necessary first of all to develop high voltage heat-stable power supply unit. We assume that the stability of 1.5% is sufficient.

The original high voltage supply module
The HPXe spectrometer is a pulse ionization chamber, so one of its features is a need to apply the high voltage to the grid and the cathode. The typical high voltage, which has to be applied to these electrodes are 15kV and 20kV. The high voltage supply based on push-pull converter.

The development of optimal
During search of the optimal scheme of investigated, but in this article we will limit ourselves to a description of the final version of thermo stable high voltage supply module The stabilization of the curren feedback using a bipolar transistor. flowing through the transformer. oltage spikes on midpoint of transformer after the stack of control pulses and igure 3).

2.
Circuit of high voltage power supply model.
oltage spikes on midpoint of transformer after the stack of he development of optimal circuit of the high voltage supply module the optimal scheme of high voltage power supply module different variants but in this article we will limit ourselves to a description of the final version of thermo high voltage supply module (see figure 4).
stabilization of the current is provided directly at the FET in the final circuit. feedback using a bipolar transistor. Thus resistors R48 and R49 determine the maximum current midpoint of transformer after the stack of control pulses and s on midpoint of transformer after the stack of different variants were but in this article we will limit ourselves to a description of the final version of thermoat the FET in the final circuit. Each FET has a esistors R48 and R49 determine the maximum current  The optimum waveform observed when the time constant τ of the RC-circuit R42C10 (R44C11) and the period of the control signals are the same. The shape of the input transformer signals will be in case of equality of these values (see figure 5). This waveform is the most preferred for high voltage supply module than rectangular, because it provides a much lower level of interference to nearby electronic components.
Result of time simulation for input voltage. The circuit R42C10 (R44C11) The shape of the input transformer signals will be his waveform is the most preferred for than rectangular, because it provides a much lower level of The voltage level was simulated for different temperatures. According to a simulation (see figure 5) developed circuit provides a change of voltage less than 30V when the temperature was increase from -50°C to 50°C, which is 1.5% of the generated voltage.

Experimental results
The developed model was verified with the breadboard. Figure 7 shows the experimental data confirming results of the time simulations. The experimental waveform has a shape close to an optimum waveform (sine wave).  According to an experimental data (see figure 8) developed circuit provides a stability of voltage better than 1% of the generated voltage when the temperature was increase from 23°C to 100°C. These results confirm the simulation.

Conclusion
The circuit of thermo-stable high voltage supply unit for spectrometer "Signal" was developed using OrCAD software. It is experimentally shown that the breadboard of the new high voltage supply unit provides the expected performance.