PERDaix
Encyclopedia
PERDaix is a novel,small and light weight magnet spectrometer to measure the charge and mass dependent solar modulation periodically for deeper understanding of cosmic rays.
For a better understanding of sources and acceleration of cosmic particles direct measurements of cosmic rays are necessary. Also for a better understanding of the solar modulation which is expected to follow the 22-year solar cycle
, time dependent measurements are needed.
PERDaix is a newly designed detector which is constructed by the Department of Physics 1b, RWTH Aachen
University. Being proposed to the German Space Agency in November 2009 for a participation in the BEXUS
Program (Rocket and Balloon Experiments for University Students) after a first canceled flight attempt in October 2010 the actual flight took place as a post-BEXUS-campaign flight opportunity in November 2010.
The detector is able to measure charged particles in the energy range of 0.5 GeV to 5 GeV. PERDaix uses a time of flight system, a scintillating fiber tracker with SiPM
readout, and a transition radiation detector in combination with a permanent magnet to measure particle fluxes.
The BEXUS balloons
are launched at Esrange Space Center
near Kiruna
, Sweden
. In November 2010 PERDaix reached a top altitude of 33.3 km at which it kept floating for 1.5 hours.
(TOF) is the upper- and lowermost layer of the detector. It consists of scintillators with an SiPM readout. It is used as a trigger signal and to discriminate against particles entering the detector from below. With a design time resolution of approximately 300 ps it can be used to distinguish between positrons and electrons in the momentum range below 1 GeV. Protons can be distinguished from positrons for momenta below 1 GeV if their velocity is lower than β = 1.
fiber tracking detector made up from 250 µm thin scintillating polystyrene fibers that emit light when traversed by a charged particle. The scintillating fibers are read out by silicon photomultiplier (SiPM) arrays which are structured semi-conductor photon detectors that offer high photon efficiencies of 50%, a high gain of 10^6 electrons / photon and that are very compact in size. One silicon photomultiplier array is 1.1mm by 8.0mm in size and has 32 channels. Twenty 32mm wide and 300mm long fiber modules are arranged in four layers around a hollow cylindrical permanent magnet array.
and weighs 8 kg and produces a very high magnetic field of ~0.26T inside of a 80mm high and 213mm diameter magnet cylinder while producing only a negligible magnetic field outside of the cylinder.
detector (TRD) is installed. The TRD detects transition radiation of relativistic particles with a lorentz factor γ exceeding ≈ 1000.
Particles crossing the interface of two media with different dielectric constant produce transition radiation. The energy loss at a boundary is proportional to the relativistic gamma factor. A significant amount of t.r. Is produced for a gamma greater than 1000. The gamma factor of protons is, up to a momentum of 5GeV still in the order of 10, whereas the positron's gamma is greater than 1000 starting at 0.5GeV momentum.
It is made up of 256 6mm thick straw tubes out of a 72 um thin multilayer aluminum-capton foil, filled with an 80/20 Xe/CO2 mixture it is used to measure the x-ray transition radiation produced by electrons in eight 20mm thick layers of an irregular fleece radiator.
This leads to more than 100 material interfaces per radiator layer.
) and Esrange
a second flight opportunity was provided in late November 2010. On the 23rd of November a 100 000 m³ helium balloon has been launched from Esrange carrying a payload of 334 kg containing the BEXUS student experiments including the PERDaix detector.
For a better understanding of sources and acceleration of cosmic particles direct measurements of cosmic rays are necessary. Also for a better understanding of the solar modulation which is expected to follow the 22-year solar cycle
Solar cycle
The solar cycle, or the solar magnetic activity cycle, is a periodic change in the amount of irradiation from the Sun that is experienced on Earth. It has a period of about 11 years, and is one component of solar variation, the other being aperiodic fluctuations. Solar variation causes changes in...
, time dependent measurements are needed.
PERDaix is a newly designed detector which is constructed by the Department of Physics 1b, RWTH Aachen
RWTH Aachen
RWTH Aachen University is a research university located in Aachen, North Rhine-Westphalia, Germany with roughly 33,000 students enrolled in 101 study programs....
University. Being proposed to the German Space Agency in November 2009 for a participation in the BEXUS
Rexus and Bexus
REXUS/BEXUS is a European programme for student experiments on rockets and balloons...
Program (Rocket and Balloon Experiments for University Students) after a first canceled flight attempt in October 2010 the actual flight took place as a post-BEXUS-campaign flight opportunity in November 2010.
The detector is able to measure charged particles in the energy range of 0.5 GeV to 5 GeV. PERDaix uses a time of flight system, a scintillating fiber tracker with SiPM
Silicon photomultiplier
Silicon photomultipliers, often called "SiPM" in the literature, are Silicon single photon sensitive devices built from an avalanche photodiode array on common Si substrate. The idea behind this device is the detection of single photon events in sequentially connected Si APDs...
readout, and a transition radiation detector in combination with a permanent magnet to measure particle fluxes.
The BEXUS balloons
High altitude balloon
High-altitude balloons are unmanned balloons, usually filled with helium or hydrogen that are released into the stratosphere, generally reaching between ....
are launched at Esrange Space Center
Esrange
Esrange Space Center is a rocket range and research centre located outside the town of Kiruna in northern Sweden. It is a base for scientific research with high altitude balloons, investigation of the aurora borealis, sounding rocket launches, and satellite tracking, among other things...
near Kiruna
Kiruna
Kiruna is the northernmost city in Sweden, situated in Lapland province, with 18,154 inhabitants in 2005. It is the seat of Kiruna Municipality Kiruna (Northern Sami: Giron, Finnish: Kiiruna) is the northernmost city in Sweden, situated in Lapland province, with 18,154 inhabitants in 2005. It is...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. In November 2010 PERDaix reached a top altitude of 33.3 km at which it kept floating for 1.5 hours.
Time of Flight System
The time of flight systemTime-of-flight
Time of flight describes a variety of methods that measure the time that it takes for an object, particle or acoustic, electromagnetic or other wave to travel a distance through a medium...
(TOF) is the upper- and lowermost layer of the detector. It consists of scintillators with an SiPM readout. It is used as a trigger signal and to discriminate against particles entering the detector from below. With a design time resolution of approximately 300 ps it can be used to distinguish between positrons and electrons in the momentum range below 1 GeV. Protons can be distinguished from positrons for momenta below 1 GeV if their velocity is lower than β = 1.
Tracker
Perdaix will make use of a scintillatingScintillation (physics)
Scintillation is a flash of light produced in a transparent material by an ionization event. See scintillator and scintillation counter for practical applications.-Overview:...
fiber tracking detector made up from 250 µm thin scintillating polystyrene fibers that emit light when traversed by a charged particle. The scintillating fibers are read out by silicon photomultiplier (SiPM) arrays which are structured semi-conductor photon detectors that offer high photon efficiencies of 50%, a high gain of 10^6 electrons / photon and that are very compact in size. One silicon photomultiplier array is 1.1mm by 8.0mm in size and has 32 channels. Twenty 32mm wide and 300mm long fiber modules are arranged in four layers around a hollow cylindrical permanent magnet array.
Magnet
The permanent magnet array is constructed as a Halbach-RingHalbach array
A Halbach array is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side...
and weighs 8 kg and produces a very high magnetic field of ~0.26T inside of a 80mm high and 213mm diameter magnet cylinder while producing only a negligible magnetic field outside of the cylinder.
Transition Radiation Detector
Underneath the lowest tracker layer a transition radiationTransition radiation
Optical Transition radiation is produced by relativistic charged particles when they cross the interface of two media of different dielectric constants. The emitted radiation is the homogeneous difference between the two inhomogeneous solutions of Maxwell's equations of the electric and magnetic...
detector (TRD) is installed. The TRD detects transition radiation of relativistic particles with a lorentz factor γ exceeding ≈ 1000.
Particles crossing the interface of two media with different dielectric constant produce transition radiation. The energy loss at a boundary is proportional to the relativistic gamma factor. A significant amount of t.r. Is produced for a gamma greater than 1000. The gamma factor of protons is, up to a momentum of 5GeV still in the order of 10, whereas the positron's gamma is greater than 1000 starting at 0.5GeV momentum.
It is made up of 256 6mm thick straw tubes out of a 72 um thin multilayer aluminum-capton foil, filled with an 80/20 Xe/CO2 mixture it is used to measure the x-ray transition radiation produced by electrons in eight 20mm thick layers of an irregular fleece radiator.
This leads to more than 100 material interfaces per radiator layer.
Launch in November 2010
Due to strong winds the launch campaign in October had to be canceled without a BEXUS-11 flight at first. Thanks to the support of German Space Agency (DLRGerman Aerospace Center
The German Aerospace Center is the national centre for aerospace, energy and transportation research of the Federal Republic of Germany. It has multiple locations throughout Germany. Its headquarters are located in Cologne. It is engaged in a wide range of research and development projects in...
) and Esrange
Esrange
Esrange Space Center is a rocket range and research centre located outside the town of Kiruna in northern Sweden. It is a base for scientific research with high altitude balloons, investigation of the aurora borealis, sounding rocket launches, and satellite tracking, among other things...
a second flight opportunity was provided in late November 2010. On the 23rd of November a 100 000 m³ helium balloon has been launched from Esrange carrying a payload of 334 kg containing the BEXUS student experiments including the PERDaix detector.