Latitudinal effect on the position of Regener-Pfotzer maximum investigated by balloon flight HEMERA 2019 in Sweden and balloon flights FIK in Czechia.

When primary space radiation particles enter into the atmosphere of the Earth, they generate showers of secondary radiation. The intensity of secondary radiation reaches its maximum, called the Regener-Pfotzer maximum; its exact position depends on the geomagnetic effective vertical cut-off rigidity, the phase of the solar cycle and also on the type of detected particles. In this paper, several balloon flight experiments are described focusing on the study of the latitudinal effect on the position of the Regener-Pfotzer maximum. Altitude profile of ionization in the atmosphere was measured using radiation detectors flown during several flights at locations with different effective vertical cut-off rigidities (flight HEMERA over Sweden and flights FIK-5 and FIK-6 over Czech Republic). The measured results are supplemented also with simulations using EXPACS 4.11 and the variation of obtained positions of Regener-Pfotzer maximum is discussed.

MEASUREMENT OF THE REGENER-PFOTZER MAXIMUM USING DIFFERENT TYPES OF IONISING RADIATION DETECTORS AND A NEW TELEMETRY SYSTEM TF-ATMON.

Stratospheric balloons are a useful tool for the investigation of cosmic radiation at high altitudes and the tests of new detectors of cosmic radiation. Due to necessary data processing, the balloon gondola needs to carry, together with radiation detectors, additional supplementary sensors measuring humidity, temperature, location and orientation, altitude, atmospheric pressure, acceleration, etc. A newly developed universal system TF-ATMON, based on using already existing tools of the PX4 open-source project, enables apart from data recording and monitoring, also the possibility to trace the balloon gondola after the flight. The application was demonstrated on stratospheric balloon flight FIK-6. This flight was unique because three different types of radiation detectors were used at one flight. It enabled us to compare the altitude of the Regener-Pfotzer maximum measured with different types of sensors sensitive to a different type of secondary cosmic radiation generated in the atmosphere.