Radiation Physics

BX33 – TOTORO (Test Observations Of Transient Objects and RadiO)

Warsaw University of Technology

Launch Date: 21 September 2023

The TOTORO project aims to design, build and launch a stratospheric zero-pressure balloon experiment dedicated to the registration of the natural emissions in Earth’s atmosphere. Main area of interest is registration of Auroral Kilometric Radiation and their analysis. The signals (low-frequency radio emissions) are picked up by two different antennas – electrical and magnetic. Signals from both antennas are processed by two independent Software-Defined Radios. Obtained data is saved in the form of continuous radio spectrums, to be processed on ground (spectral analysis etc.). It will be analysed in search of traces of desired natural phenomena, as well as additional information (signal-to-noise ratio at low frequencies, field strength intensities of terrestrial longwave stations etc.). The data will be used as an aid in analysis of similar signals recorded on orbital altitudes. The project shall also allow the students to gain important experience in space project management, international cooperation and achieving a scientific goal using engineering skills.

RX32 – PR4 (Payload for Radiation measurement and Radio-interferometry on Rockets Revisited)

Radboud University, Utrecht University and Eindhoven University of Technology

Launch Date: March 2024

The Payload for Radiation measurement and Radio-interferometry in Rockets Revisited (PR4) project aims to develop a two-part payload on the REXUS 31/32 rocket. The first experiment uses radio-interferometry for live location and orientation tracking of the sounding rocket during flight. The second experiment performs astrophysical measurements by characterizing the flux and arrival direction of cosmic rays using a detector built to CubeSat specifications.

The radio-interferometry tracking system has an expected centimetre-scale accuracy, with an update rate of 1 kHz. Three radio antennas are mounted on the outside of the rocket module, transmitting carrier signals at three distinct wavelengths close to 70 cm. These signals are received by several ground stations placed around the Esrange launch site. Each ground station performs multi-antenna phase-difference measurements to constrain signal arrival direction. The phase-difference data is sent over wired and wireless connections to a central server where all data is combined to reconstruct the rocket position. The three independent solutions that can be calculated using the three different signals allow for estimation of the rocket attitude and the accuracy of the system.

The cosmic-ray detection will be done by a multi-layer detector built with 2U CubeSat dimensions. The arrival direction of the cosmic-ray particles is characterized by studying the energy deposited in the different detector layers. This experiment provides a unique opportunity to study cosmic rays in the domain between ground-based detectors and space-based detectors. Additionally, it serves as a pathfinder for a future CubeSat project to investigate the correlation between cosmic-rays and atmospheric cloud formation. This experiment is complemented by the radio-interferometry experiment, since the arrival of the cosmic rays can be estimated more accurately using the location and orientation data acquired by the tracking experiment.

BX29 – IROCS (Influence of radiation on charged spheres)

University of Duisburg-Essen, Germany

Launch Date: 23 October 2019

When insulating grains collide, they charge electrically. Identical particles charge and, being overall neutral, they can form large aggregates. This is important in the context of planet formation. Charging can be seen on ground and first steps of aggregation can be seen in drop tower experiments. However, in recent experiments on the ISS collisional charging was strongly reduced. Being identical to drop tower experiments in all parameters usually discussed for charging (temperature, humidity, pressure, material), the influence of cosmic radiation is left as parameter of unknown importance. Radiation can ionize the gaseous environment, increasing the conductivity, and potentially causing neutralization of the charges.
To test this hypothesis and quantify the effect especially with natural distribution of cosmic radiation, we build an experiment for BEXUS which is able to measure charges on single collisionally charged glass spheres during the flight. While the experiment’s atmosphere is kept constant by a pressure vessel, cosmic radiation will increase and reduce the measured number of
charges. Two reservoirs of spheres will rotate, leading to collisions and charging. They are linked by a narrow copper ring. Depending on the orientation, individual spheres pass through the ring by gravity and a mirror charge is induced in the copper. A highly sensitive charge detector measures
this induction depending on the height.

BX29 – TANOS (Thermal atmospheric neutron observation system)

Kiel University, Germany

Launch Date: 23 October 2019

The main objective of TANOS is to measure the flux of thermal neutrons in the stratosphere, as there are only few existing measurements.
Due to galactic cosmic rays interacting with atmospheric particles, secondary neutrons are generated. Those are moderated to thermal energies through elastic scattering. These resulting neutrons are very slow, with an energy of 0.025 eV. The flux of secondary particles is the largest at a height of about 20 km, the so called Pfotzer maximum.
In order to measure these low energy neutrons we developed an instrument consisting of a silicon detector stack and two layers of gadolinium foil between two detectors. The cross section of gadolinium is very high for thermal neutrons, around 49000 barn, thus this material is particularly suitable for the experiment.

BX24 – NEMESYS (Neutron Effects on Memory SYStems)

University of Rome Tor Vergata, Italy

Launch Date: 18 October 2017

NEMESYS’s (Neutron Effects on MEmory SYStems) aim is to study the effects of particles impact on a memory board as function of the environment. Electromagnetic Field, Lightning Events, altitude and coordinates will be monitored during the whole experiment; trying to obtain a correlation between environment factors and soft errors.

The experimental setup will consist of several boards with processors, each one managing different sensors and activities: such hardware redundancy is chosen to allow parallel working groups, to achieve modularity, and to make the system more reliable. One board will manage environmental sensors (altitude, pressure, temperature, lightning events detector); another will manage a GPS module to acquire data regarding the position of the whole system; another board will manage the memory arrays that are used as “bit-flip” detectors; the last processor will be in charge of managing a camera (used to detect and measure the flux of particles), communication through Ethernet link, saving data on SD memory card.

RX17 – REM-RED (GM Sounding Rocket Experiment to Measure the Cosmic Radiation and Estimate its Dose Contribution)

Budapest University of Technology and Economics, Hungary

Launch Date: 17 March 2015

The REM-RED experiment aims to design and develop a GM counter system for sounding rockets and to quantify the cosmic radiation up to the maximum altitude of the REXUS rocket. The teams will measure the direction dependence of the cosmic radiation, the altitude dependence of the count rates and thus estimate the dose rate altitude dependence based on the GM calibrations.

BX18 – AFIS-P (Antiproton Flux In Space – Prototype)

Technische Universität München, Germany

Launch Date: 10 October 2014

AFIS-P’s primary scientific objective is to measure the flux of charged particles (mainly protons, but also light ions) at very low energies in the stratosphere. These particles originate either directly from the galactic cosmic ray (CR) spectrum, or are of secondary origin, being produced in interactions of CR radiation with Earth’s atmosphere. The novel working principle of AFIS-P’s particle detector will be used in active research for the first time. It is sensitive for charged particles with energies between 20 and 100 MeV-per-nucleon and is the first full-scale prototype of the AFIS detector to be constructed. AFIS-P is a precursor to the actual Antiproton Flux in Space (AFIS) mission, whose goal is to measure the flux of antiprotons trapped in Earth’s magnetic field. AFIS-P will address both the physics as well as the engineering challenges that have to be met for such a mission. Besides physics research there are two main technical goals for AFIS-P: First, the development of the hardware and electronics necessary for an experiment on a satellite mission within all constraints given by the space environment and satellite specifications. Second, to collect a large enough data sample that can be analyzed to determine whether the detection principle of the AFIS detector works and can implemented on a satellite mission.

BX19 – ADAM (Angular Distribution of charged particles, Atmosphere Measurement)

Christian-Albrechts-Universität zu Kiel, Germany

Launch Date: 8 October 2014

Due to the interaction of cosmic rays with atmospheric molecules, a particle shower consisting of a large number of various particles is induced in the atmosphere. The objective of team ADAM is to measure the angular dependency in respect to the zenith-angel of these charged particles in the atmosphere at a height of 25km. This is above the “Pfotzer-Maximum” at which the particle flux hits the maximum. The detection of the particles will be realised by a sensor head composed out of several silicon semiconductor-detectors (SSDs) in such a geometrical order, that conclusions about the arrival angle of incoming particles can be drawn by coincidence measurement. To optimise the sensor head we are simulating the geometric arrangement of the SSDs before the flight. As a second mission objective we plan to compare the measured data with data from planet Mars’ surface which has similar atmospheric conditions as earth in 25km height.

RX14 – Gekko (Measurement of the variation in electric conductivity with altitude)

Budapest University of Technology and Economics, Hungary

Launch Date: 7 May 2013

The scientific objective of the Gekko experiment is to study the ionisation of the atmosphere at varying altitudes. Direct measurements are to be taken of the variations in electrical conductivity with altitude, by recording the mobility spectrum of positive and negative ions. The measurements will be performed using Gerdien Condensers. Such Investigations are particularly interesting at higher latitudes, where galactic cosmic rays have a greater impact on the ionisation processes. This means that not only particles of greater penetrating depth, due to the lower ionosphere, but also greater fluxes due to the decrease in magnetic rigidity should also be considered. The polar region, in which the measurements will be conducted, is also of interest from the point of view of ionisation processes caused jointly by the direct connection to the tail of the magnetosphere, and from interplanetary space. Therefore it is suitable from time to time, to monitor the state of the atmosphere not only at greater altitudes, but higher latitudes also.

Gekko Conference Paper

Gekko Final SED

BX14 – MONSTA (Measurement Of Neutrons with Scintillators in The Atmosphere)

Christian-Albrechts University in Kiel, Germany

Launch Date: 24 September 2012

The intensity of galactic cosmic rays is altered by the modulation in the heliosphere and the transport in the magnetosphere before they interact with the molecules and atoms of the atmosphere. The radiation environment in the atmosphere is therefore determined by the generation of secondary charged and neutral particles i.e. electrons, muons and protons as well as neutrons and gamma rays. These particles undergo the same interactions as the primary cosmic rays leading to a particle flux maximum at a height of about 20 km (Pfotzer-Maximum). In order to measure the radiation dose it is necessary to measure the altitude dependent flux of the neutral particles i.e. neutrons, gamma rays and charged particles simultaneously. To gain the scientific objective, we are planning to use a Phoswich detector. After the balloon flight, it could be possible to distinguish between neutrons and gamma rays using a statistical method. Furthermore count rates, dose rates and pulse height spectra can be calculated after the flight.

MONSTA Conference Paper

BX14 – TECHDOSE (Development of a Complex Balloon Technology Platform for Advanced Cosmic Radiation and Dosimetric Measurements)

Budapest University of Technology and Economics, Hungary

Launch Date: 24 September 2012

The altitudes at which commercial aircraft operate and the frequency of manned spaceflights have increased dramatically over the past several decades. These facts justify the importance of cosmic radiation and dosimetric measurements, through the use of advanced instruments and techniques. Many measurements have been taken of the cosmic radiation field from the surface of the Earth, up to the operational ceiling of research aircraft (which is the lower limit of the stratosphere). However, the cosmic radiation environment is not well known between the altitude ranges of 15 – 30 km. The primary scientific goal of the TECHDOSE experiment is to give a comprehensive assessment of the cosmic radiation field at the operating altitude of the BEXUS balloon; and the main technical goal is to develop a balloon technology platform for advanced cosmic radiation and dosimetric measurements. To fulfill the objectives of this experiment, several different dosimeter systems will be utilised, including: an advanced version of TriTel silicon detector telescope, Geiger-Müller (GM) counters, Pille and PorTL thermo-luminescent passive dosimeters (with portable readout), Solid State Nuclear Track Detectors (SSNTDs) and a Solid State TL Dosimetry system (with conventional TL reader). The SSNTD will determine the contribution of thermal neutrons to the radiation field, whilst the Solid State TL will quantify the effects of particles of low and high (mixed) linear energy transfer. The evaluated deposited energy spectra measured by the improved TriTel instrument will be compared against the count-rates of the GM counters, in order to calibrate them for dose rates in the cosmic radiation field. These results will be compared against those obtained from the BX12 CoCoRAD experiment, and data provided by the Hungarian Heliophysical Observatory to detect any possible changes in solar activity.

TECHDOSE Conference Paper

BX12 – CoCoRAD (Combined TriTel/Pille Cosmic RADiation Dosimetric Measurements)

Budapest University of Technology and Economics, Hungary

Launch Date: 25 September 2011

The objective of the CoCoRAD experiment is to measure the effects of cosmic radiation at lower altitudes, where measurements from orbiting spacecraft are not possible due to atmospheric drag. Due to significant spatial and temporal changes in the Earths cosmic radiation field, it is vital that continuous radiation measurements are taken using dosimetric instruments on-board spacecraft, aircraft and stratospheric balloons. CoCoRAD aims to use two separate dosimetric devices to make a comparison of the measured doses. This represents the first time that LET spectra from a TriTel 3D silicon detector telescope has been used for corrections during data evaluation of a Pille thermo-luminescent dosimeter. By evaluating the deposited energy spectra recorded by TriTel and the glow curve obtained from ground-based read-outs of the retrieved Pille dosimeter; the LET spectrum, the average quality factor of the cosmic radiation as well as the absorbed dose and the dose equivalent can be determined. The results of the two measurements will be compared and used to make an estimation of the dosages that might be expected during the launch of manned space flights or even commercial air flights.

CoCoRAD Conference Paper

BX13 – RETA (Radiation Exposure in The Atmosphere)

Christian-Albrechts University in Kiel, Germany

Launch Date: 26 September 2011

The aim of the RETA experiment is to investigate radiation dose rate’s dependence on altitude, at solar minimum in high latitudes. The Earth is permanently exposed to energetic particle radiation from cosmic rays. This cosmic particle radiation yields, together with its terrestrially produced secondary particles, a natural radiation field inside the atmosphere. This complex radiation field is composed of charged and neutral particles. The charged particles are mainly protons, alpha-particles, electrons, muons and some heavy nuclei. The neutral particles are neutrons and gamma-rays. The radiation exposure is dependent on the altitude and the geomagnetic latitude, because the radiation field is modulated by the Earth’s magnetic field. For this investigation a particle telescope consisting of four segmented silicon semiconductor detectors was developed. Due to the arrangement of the detectors, it is possible to separate neutral and charged particles and the calculated dose rates can be converted into a dose equivalent rate, which is the unit for radiation protection. Because of the relatively slow rate of climb of the balloon, the dose rate dependence on the altitude up to 35 km can be measured in one flight, and therefore above and below the Pfotzer maximum.

BX11 – PERDaix (Proton Electron Radiation Detector – Aix-La-Chapelle)

Aachen University, Germany

Launch Date: 23 November 2010

The goal of the PERDaix experiment was to flight test a prototype balloon-borne experiment platform, designed to detect charged particles within the upper atmosphere. The experiment was designed to measure charged cosmic rays in the energy region between 0.5 GeV and 5 GeV and to identify the effects of solar modulation by measuring the individual fluxes of helium, protons, electrons and positrons. By focusing on the ratio of positrons to electrons, as well as the absolute fluxes of the different particle types, PERDaix could measure the current solar modulation and test different models for cosmic ray transportation in the heliosphere and the properties of the interplanetary magnetic field. The experiment consisted of a magnet spectrometer with a permanent magnet and a scintillating fibre tracking detector, a transition radiation detector and a time-of-flight system which recorded the trajectory and charge flux of the charged particles. This information was then stored for post-flight analysis. The PERDaix experiment aimed to collect valuable information for the production and operation of a much larger balloon-borne detector for charged cosmic rays.

PERDaix Conference Paper

BX11 – Laertes (Characterisation of radiative environment by neutron flux measurement)

University of Montpellier 2, France

Launch Date: 23 November 2010

The Laertes experiment aimed to characterise atmospheric neutron flux at high altitudes (>20 km), and compare the results against those obtained from theoretical studies. Incoming cosmic rays can cause major problems to ground and air based electronic equipment, especially those utilising integrated devices. This naturally occurring source of radiation is mainly composed of neutrons whose flux is known to rapidly increase with elevation. To map the atmospheric neutron flux a large Silicon Diode system was used, which was able to detect nuclear reactions in the diode, thereby determining the energy released by each nuclear reaction. A large diode was necessary as the probability of a neutron interacting with the diode, and hence being detected is proportional to its volume. Physically, these nuclear reactions produce secondary ions in the diode which create electron-hole pairs. The charges were then collected using an electrical field. All collected results were to be compared against simulated neutron flux models, in order to verify the validity of the existing theory.

BX09 – CRIndIons (Cosmic Ray Induced Ionisation)

Lulea University of Technology, Sweden, Charles University, Prague, Czech Technical University, Czech Republic

Launch Date: 11 October 2009

The main focus of the CRIndIons experiment was to conduct high-precision, in situ measurements of atmospheric Cosmic Ray Induced Ionisation (CRII), with particular attention paid to its rate and associated ambient ion concentration according to induced flux theories. At present there is still a high level of ambiguity regarding specific ionisation processes, and their effect on magnetospheric and atmospheric physics. This can further impact global atmospheric currents and meteorological conditions. While CRII is generally known to occur between the altitudes of 3-35 km, and the relevant cosmic ray fluxes are well documented, more specific data on its ionisation yields is still required. This is heavily dependent on particle types and their associated energies. These parameters were measured using Timepix and Medipix-2 hybrid pixel detectors, which identify and separate different types of particles by their distinctive track patterns. The detectors were used in tracking mode allowing them to operate as an “active nuclear emulsion”. Extensive datasets of different types of cosmic ray tracks were acquired in the stratospheric radiation environment, sorted and analysed. The detectors performance was then evaluated for further design implications of proposed usage on satellites.

CRIndIons Conference Paper

BX07 – TimePiX@Space (Radiation Profiles)

Lulea University of Technology, Sweden, Charles University, Prague, Czech Technical University, Czech Republic

Launch Date: 8 October 2008

The primary goal of the TimePiX experiment was to record height dependant, atmospheric radiation profiles using Medipix2/Timepix type, hybrid pixel detectors. These detectors operate by transforming energy, deposited from charged particle collisions in the active material of the detector, into charge which is collected by pixel electronic read-outs. The pixel detector can count individual quanta of radiation, and as multiple electrons are collected, a counter is increased. The detector responds differently for individual types of radiation, by producing a distinct track pattern, therefore allowing a complete radiation profile to be produced. During the BEXUS flight, the TimePiX experiment collected the radiation deposits and classified them into categories based on their track patterns. From each category, certain features were identified to determine the radiation type. The energy deposited in the detectors was estimated by using calibration measurements with different types of radiation, and varying discrimination thresholds. From this a complete view of the radiation conditions along the balloon flight path was obtained. All results were analysed on a statistical basis, and any unidentified particles were estimated using existing measurements from radioactive sources or MC simulations.