THE AUGER ENGINEERING RADIO ARRAY

The Auger Engineering Radio Array currently measures MHz radio emission from extensive air showers induced by high energy cosmic rays with 24 self-triggered radio detector stations. Its unique site, embedded into the baseline detectors and extensions of the Pierre Auger Observatory, allows to study air showers in great detail and to calibrate the radio emission. In its final stage AERA will expand to an area of approximately 20km2 to explore the feasibility of the radio-detection technique for future cosmic-ray detectors. The concept and hardware design of AERA as well as strategies to enable self-triggered radio detection are presented. Radio emission mechanisms are discussed based on polarization analysis of the first AERA data

Экономическая оценка энергосберегающих проектов

В пособии рассмотрены понятия инвестиций проектов и проектного анализа, анализа финансовой деятельности предприятия. Представлены методы оценки экономической эффективности внедрения энергосберегающих проектов, сравнительного анализа их с альтернативными вариантами. Рассмотрены различные схемы финансирования энергосберегающих проектов, включая варианты использования патентов, лицензий. Предназначено для студентов энергетических и экономических специальностей

Highly Accurate Radar Cross Section and Transfer Function Measurement of a Digital Calibration Transponder without Known Reference - Part I: Measurement & Results

Active Radar Calibrators (ARC), also called calibration transponders, are often used as reference targets for absolute radiometric calibration of radar systems due to their large achievable Radar Cross Section (RCS). But before using a transponder as a reference target, the hardware has to be calibrated itself. A novel method, called three-transponder-method, was proposed some years ago and allows for RCS calibration of digital transponders without using any RCS target as reference. In this paper, this technique is further refined and applied to a setup utilizing only one digital transponder. The accurate measurement design is described and a novel, elaborated data processing scheme is developed to minimize remaining noise and clutter effects in the data. A comprehensive error analysis will be presented in the second part of this paper

Absolute Radiometric Calibration of Broadband X-Band Transponders

Spaceborne synthetic aperture radar (SAR) systems are often used for earth observation capable for acquiring accurate high-resolution data. In order to ensure the quality of these SAR data, the SAR system has to be calibrated first. For this purpose active targets with well-known backscatter properties, called transponders, serve as an external reference. The enhancement of the operational bandwidth up to 1.2 GHz of future civil SAR systems requires the development of appropriate broadband transponders and their accurate calibration. In order to be well prepared for these missions, DLR has been developed a broadband X-Band transponder and an innovative technique for the frequency-dependent determination of the transponder’s radar cross section (RCS) which promises an accurate measurement over the full transponder bandwidth. In this paper the calibration of a broadband transponder according to this new approach is described including the analysis of corresponding measurements. The derived results are verified with a second independent calibration method and finally evaluated

A field study of data analysis exercises in a bachelor physics course using the internet platform VISPA

Bachelor physics lectures on particle physics and astrophysics were complemented by exercises related to data analysis and data interpretation at the RWTH Aachen University recently. The students performed these exercises using the internet platform VISPA, which provides a development environment for physics data analyses. We describe the platform and its application within the physics course, and present the results of a student survey. The students acceptance of the learning project was positive. The level of acceptance was related to their individual preference for learning with a computer. Furthermore, students with good programming skills favor working individually, while students who attribute themselves having low programming abilities favor working in teams. The students appreciated approaching actual research through the data analysis tasks.Comment: 21 pages, 8 figures, 1 table, for the internet platform VISPA see http://vispa.physik.rwth-aachen.d

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO