Abstract: The main objective of the Advanced GAmma Tracking Array (AGATA) is the investigation of the structure of exotic nuclei at the new generation of RIB facilities. As part of the preparatory phase for FAIR-NUSTAR, AGATA is going to be installed at the FRS fragmentation facility of the GSI centre for an experimental campaign to be performed in 2012 and 2013. Owing to its gamma-ray tracking capabilities and the envisaged enhancement in resolving power, a series of in-flight gamma-ray spectroscopy experiments are being planned. The present work describes the conceptual design of this first implementation of AGATA at GSI-FRS, and provides information about the expected performance figures. According to the characteristics of each particular experiment, it is foreseen that the target-array distance is adjusted in order to achieve the optimum compromise between detection efficiency and energy resolution, or to cover an specific angular range of the emitted electromagnetic radiation. Thus, a comprehensive Monte Carlo study of the detection sensitivity in terms of photopeak efficiency, resolution and peak-to-total ratio, as a function of the target-array distance is presented. Several configurations have been investigated, and MC-calculations indicate that a remarkable enhancement in resolving power can be achieved when double-cluster AGATA detectors are developed and implemented. Several experimental effects are also investigated. This concerns the impact of passive materials between the target and the array, the angular distribution of the detection efficiency and the influence of target thickness effects and transition lifetimes in the attainable detection sensitivity. A short overview on half-life measurements via lineshape effects utilizing AGATA is also presented. (C) 2012 Elsevier B.V. All rights reserved.

Abstract: The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected gamma-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted gamma-ray. The gamma-ray tracking was used to determine the full energy of the gamma-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of <1 mm in the FVVHM of the interaction position resolution for the gamma-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a (30)5i beam at 64 MeV on a thin C-12 target. Pulse-shape analysis of the digitized detector waveforms and gamma-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the gamma-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FVVHM of the interaction position resolution varies roughly linearly as a function of gamma-ray energy from 8.5 mm at 250 key to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the gamma-ray energy range from 1.5 to 4 MeV.

Abstract: Purpose: This work aims to create and validate a comprehensive set of test cases and 3D reference dosimetric datasets for model-based dose calculation algorithms (MBDCAs) in permanent implant prostate brachytherapy. These test cases address the limits of the standard TG-43 formalism towards improving dose evaluations in prostate cancer treatment, in accordance with the recommendations of the joint Task Group 186 of the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG). Acquisition and Validation Methods: Six test scenarios using the I-125 OncoSeed 6711 were simulated with three Monte Carlo codes: EGSnrc application egsbrachy with ebgui, MCNP with BrachyGuide, and PenRed. The test cases range from basic, e.g., single seed in water, to more complex configurations, e.g., 58 seeds in a virtual patient model for prostate treatment. The virtual model was developed from anonymized CT-based images, representing a real patient with and without calcifications. Dose comparisons were performed using both local and global metrics, with eb_gui as the reference for validation. For all test cases, the local agreement of Monte Carlo codes was within similar to 3.0% and the global agreement was 0.01%. Data Format and Usage Notes: The dataset, including Monte Carlo input files and other required information, is available online at https://doi.org/10.5281/zenodo.15282647. Potential Applications: The developed test cases provide an essential resource for the development, validation, and commissioning of MBDCAs. They have the potential to improve dosimetric accuracy in complex prostate implants while also providing a platform for future brachytherapy research.