ABSTRACT
We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16} eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17} eV.
ABSTRACT
We report the observation of a steepening in the cosmic ray energy spectrum of heavy primary particles at about 8×10(16) eV. This structure is also seen in the all-particle energy spectrum, but is less significant. Whereas the "knee" of the cosmic ray spectrum at 3-5×10(15) eV was assigned to light primary masses by the KASCADE experiment, the new structure found by the KASCADE-Grande experiment is caused by heavy primaries. The result is obtained by independent measurements of the charged particle and muon components of the secondary particles of extensive air showers in the primary energy range of 10(16) to 10(18) eV. The data are analyzed on a single-event basis taking into account also the correlation of the two observables.
ABSTRACT
BACKGROUND: The so-called "supraclavicular" region bears the confluence of deep jugular, upper mediastinal and axillary lymph node groups and therefore it is often part of the target volume in common malignancies like lung cancer, breast cancer and head and neck cancer. For treating this area, several authors recommend an anterior portal with the dose prescribed to a tissue depth of 3 cm, which does not fit our institution's experience. PATIENTS AND METHODS: In 119 consecutive patients a computed tomography for planning purposes was performed. We used the subclavian blood vessels between clavicula and first rib as an estimate of the confluence of the mentioned lymph node regions and determined their tissue depth (which does not describe the deepest part of the lymph vessels). RESULTS: Mean and median of the tissue depth were 5 cm in a range from 2 to 9 cm. Only in less than 20% of the measurements we found the vessels located 3 cm or less under the surface which would correspond to a depth of the lymph node target volume 4 to 5 cm. Increasing body mass resulted in deeper location of the vessels. The position of the patient's arms influenced the tissue depth even more. Arms risen above the head resulted in 55% of the measurements in tissue depths of 6 cm or deeper compared to 6% in patients treated with arms beside the body. CONCLUSION: Standardized treatment prescriptions do not cope adequately with individual anatomy. Treatment position especially of the arms influences location of the "supraclavicular" lymph node region in thoracic treatment. Target volume delineation by computed tomography seems the most accurate solution, although it is the most expensive one. Patient immobilization is crucial for accuracy of treatment delivery.