M. Bardet

In-flight measurements of energetic radiation from lightning and thunderclouds

In the certification procedure aircraft builders carry out so-called icing tests flights, where the zero degree Celsius altitude is deliberately sought and crossed in or under thunderstorms. Airbus also used these flights to test ILDAS, a system aimed to determine lightning severity and attachment points during flight from high speed data on the electric and magnetic field at the aircraft surface. We used this unique opportunity to enhance the ILDAS systems with two x-ray detectors coupled to high speed data recorders in an attempt to determine the x-rays produced by lightning in-situ, with synchronous determination of the lightning current distribution and electric field at the aircraft. Such data are of interest in a study of lightning physics. In addition, the data may provide clues to the x-ray dose for personnel and equipment during flights. The icing campaign ran in April 2014; in six flights we collected data of 61 lightning strikes on an Airbus test aircraft. In this communication we briefly describe ILDAS and present selected results on three strikes, two aircraft initiated and one intercepted. Most of the x-rays have been observed synchronous with initiating negative leader steps, and as bursts immediately preceding the current of the recoil process. Those processes include the return stroke. The bursts last one to four micro-second and attain x-ray energies up to 10 MeV. Intensity and spectral distribution of the x-rays and the association with the current distribution are discussed. ILDAS also continuously records x-rays at low resolution in time and amplitude.

Active CO2 two-phase loops for the AMS-02 tracker

The Alpha Magnetic Spectrometer AMS-02 [1]-[4] is an astro particle physics experiment running on the International Space Station (ISS; see Figure 1) since May 19, 2011. Its missions include the search for antimatter and the identification of the nature of dark matter. The AMS silicon tracker is the only subdetector inside the AMS permanent magnet that can detect the charge of a moving particle to distinguish an anti-particle from particle (see Table 1 for nomenclature).

The control electronics of the silicon tracker cooling system of the AMS-02 experiment

AMS-02 is a space experiment that will perform cosmic ray observations on board of the International Space Station starting from July 2009. This presentation describes the control electronics for the silicon tracker cooling system in the AMS-02 apparatus. It also contains a brief description of the tracker detector and its cooling system necessary for the description of the electronics. The tracker cooling system includes a set of various sensors and actuators which are necessary for bringing the tracker detector to a uniform temperature at which it can operate correctly. The sensors include: Pt1000 thermistors, semiconductor thermal sensors, differential and absolute pressure sensors, and pump rotational speed sensors. The actuators are: resistive heaters, peltier heat pumps, and liquid pumps. The electronics process the sensor signals, control the actuators, and perform automatic safeguard actions so that the system is capable of operating in a stand-alone mode, i.e. without operator intervention. The electronic system also sends relevant operational data to ground. This paper will describe the design, construction and space qualification of these control electronics.

Window sensor for the A350 and A380 aircraft

When lightning strikes an aircraft, the current distribution and the attachment points are of interest. Simple window sensors mounted in different windows along the fuselage provide signals over the local magnetic field due to lightning current, its orientation and time behavior.

In‐Flight Observation of Positron Annihilation by ILDAS

Abstract We report a 511‐keV photon flux enhancement that was observed inside a thundercloud and is a result of positron annihilation. The observation was made with the In‐flight Lightning Damage Assessment System (ILDAS) on board of an A340 test aircraft. The aircraft was intentionally flying through a thunderstorm at 12‐km altitude over Northern Australia in January 2016. Two gamma ray detectors showed a significant count rate increase synchronously with fast electromagnetic field variations registered by an on‐board antenna. A sequence of 10 gamma ray enhancements was detected, each lasted for about 1 s. Their spectrum mainly consists of 511‐keV photons and their Compton component. The local electric activity during the emission was identified as a series of static discharges of the aircraft. A full‐scale Geant4 model of the aircraft was created to estimate the emission area. Monte Carlo simulation indicated that the positrons annihilated in direct vicinity or in the aircraft body.

In‐Flight Observation of Gamma Ray Glows by ILDAS

Abstract An Airbus A340 aircraft flew over Northern Australia with the In‐Flight Lightning Damage Assessment System (ILDAS) installed onboard. A long‐duration gamma ray emission was detected. The most intense emission was observed at 12 km altitude and lasted for 20 s. Its intensity was 20 times the background counts, and it was abruptly terminated by a distant lightning flash. In this work we reconstruct the aircraft path and event timeline. The glow‐terminating flash triggered a discharge from the aircraft wing that was recorded by a video camera operating onboard. Another count rate increase was observed 6 min later and lasted for 30 s. The lightning activity as reported by ground networks in this region was analyzed. The measured spectra characteristics of the emission were estimated.

The electronic ground support equipment for the silicon tracker cooling system of the AMS-02 experiment

AMS-02 is a space experiment that will perform cosmic ray studies on board of the international space station starting from July 2009. This paper describes the design and production of electronic ground support equipment (EGSE) that emulates the silicon tracker cooling system in the AMS-02 apparatus. This emulator is needed in order to test the control electronics of the cooling system without the cooling system itself. The cooling system will be assembled and integrated separately and with a different schedule. Using the EGSE, with a proper emulation software, it will also be possible to simulate the behavior of the cooling system in space. The tracker cooling system includes a set of different sensors and actuators which are necessary for bringing the tracker detector to a uniform temperature at which it can operate properly. The sensors include: Pt1000 thermistors, semiconductor thermal sensors, differential and absolute pressure sensors, and pump rotational speed sensors. The actuators are: resistive heaters, Peltier heat pumps and liquid pumps. The EGSE should simulate the behavior of all these sensors and actuators. This means that it must generate the same signals from the electrical point of view but also its global behavior, namely the response to any internal and external condition change should be the same as the actual tracker cooling system. In order to achieve this performance appropriate software that includes the simulated response of the tracker cooling system will be developed. The EGSE has been developed in three phases: in phase 1 we emulated the electrical behavior of each sensor or actuator as a single unit, in phase 2 we integrated those sensors in a single unit and we added a USB computer interface and basic control software. In phase 3 we will develop software emulating the behaviour of the entire tracker cooling system.