A software package for modeling segmented High-Purity Segmented Germanium detectors, AGATAGeFEM, is presented. The choices made for geometry implementation and the calculations of the electric and ...weighting fields are discussed and models used for charge-carrier velocities are described. Numerical integration of the charge-carrier transport equation is explained. The impact of noise and crosstalk on the achieved position resolution in AGATA detectors is investigated. The results suggest that crosstalk, as seen in the AGATA detectors, is of minor importance for the position resolution. The sensitivity of the pulse shapes to the parameters in the pulse-shape calculations is determined as a function of position in the detectors. Finally, AGATAGeFEM has been used to produce pulse-shape data bases for pulse-shape analyses of experimental data. The results with the new data base indicate improvement with respect to those with the standard AGATA data base. The AGATAGeFEM package sets itself apart with its high precision of the detector geometry description. This lends itself to numerical studies of the impact of segmentation lines and charge diffusion in the next step of code development.
γ
-ray spectroscopy of fission fragments is a powerful method for studies of nuclear structure properties. Recent results on the spectroscopy of fission fragments, using the combination of the AGATA
...γ
-ray tracking array and the VAMOS++ large acceptance magnetic spectrometer at GANIL, are reported. A comparison of the performance of the large germanium detector arrays EXOGAM and AGATA illustrates the advances in
γ
-ray spectroscopy of fission fragments. Selected results are highlighted for prompt
γ
-ray spectroscopy studies, measurements of short lifetimes of excited states with the Recoil Distance Doppler-Shift method, using both AGATA and VAMOS++ and prompt-delayed
γ
-ray spectroscopy studies using AGATA, VAMOS++ and EXOGAM.
AGATA is a modern
γ
-ray spectrometer for in-beam nuclear structure studies, based on
γ
-ray tracking. Since more than a decade, it has been operated performing experimental physics campaigns in ...different international laboratories (LNL, GSI, GANIL). This paper reviews the obtained results concerning the performances of
γ
-ray tracking in AGATA and associated algorithms. We discuss
γ
-ray tracking and algorithms developed for AGATA. Then, we present performance results in terms of efficiency and peak-to-total for AGATA. The importance of the high effective angular resolution of
γ
-ray tracking arrays is emphasised, e.g. with respect to Doppler correction. Finally, we briefly touch upon the subject of
γ
-ray imaging and its connection to
γ
-ray tracking.
The unprecedented capabilities of state-of-the-art segmented germanium-detector arrays, such as AGATA and GRETA, derive from the possibility of performing pulse-shape analysis. The comparison of the ...net- and transient-charge signals with databases via grid-search methods allows the identification of the
γ
-ray interaction points within the segment volume. Their precise determination is crucial for the subsequent reconstruction of the
γ
-ray paths within the array via tracking algorithms, and hence the performance of the spectrometer. In this paper the position uncertainty of the deduced interaction point is investigated using the bootstrapping technique applied to
60
Co radioactive-source data. General features of the extracted position uncertainty are discussed as well as its dependence on various quantities, e.g. the deposited energy, the number of firing segments and the segment geometry.
The design study of the AGATA array began with the development of the AGATA simulation code using GEANT4. The latter played a key part in the final design of the array and provided a cost effective ...solution for the early development of the tracking algorithm. The code has since been maintained and developed by the collaboration to provide more realistic simulations, with reaction chambers, ancillary detectors and surrounding mechanical structures completing the entire setup.
Agata characterisation and pulse shape analysis Boston, A. J.; Crespi, F. C. L.; Duchêne, G. ...
European physical journal. A, Hadrons and nuclei,
09/2023, Letnik:
59, Številka:
9
Journal Article
Recenzirano
Odprti dostop
The AGATA and GRETA spectrometers are large arrays of highly segmented HPGe detectors that use the technique of gamma ray tracking to reconstruct the scattering path of gamma rays interacting within ...the active material. A basic requirement is a precise reconstruction of the individual interaction locations within the detectors. This is possible through the use of pulse shape analysis which has to be conducted in real time due to the high data rates generated by the spectrometer. The methodologies that have been evaluated to perform this for AGATA are discussed along with the approaches used to calculate the pulse shape databases required by these algorithms. Finally, the performance and limitations of the existing approaches are reviewed.
The AGATA tracking detector array represents a significant improvement over previous Compton suppressed arrays. The construction of AGATA led to numerous technological breakthroughs in order to meet ...the requirements and the challenges of building a mobile detector across Europe. This paper focuses on the design and implementation of the data acquisition system responsible of the readout and control of the germanium detectors of AGATA. Our system is highly versatile, capable of instrumenting AGATA and seamlessly adapting it to various configurations with a wide range of ancillary detectors and/or spectrometers. It consists of three main components: an autonomous and independent infrastructure, a dedicated application core ensuring overall consistency, and a high-performance software package providing a fully integrated data flow management including the setting-up, the supervision and the slow control of the instrument. In this paper, we present a comprehensive analysis of the system’s design and performance, particularly under high-counting rate conditions.
Lifetimes of states in the ground-state bands of (70)Se and (72)Se were measured using the recoil-distance Doppler shift method. The results deviate significantly from earlier measurements, requiring ...a revision of the conclusions drawn from a recent Coulomb excitation experiment concerning the shape of (70)Se. The new results lead to a coherent picture of shape coexistence in the neutron-deficient selenium and krypton isotopes. The coexistence and evolution of oblate and prolate shapes in this mass region is for the first time consistently described by new Hartree-Fock-Bogolyubov-based configuration-mixing calculations which were performed using the Gogny D1S interaction.
The lifetimes of the first excited 2{sup +} states in {sup 62}Fe and {sup 64}Fe have been measured for the first time using the recoil-distance Doppler shift method after multinucleon transfer ...reactions in inverse kinematics. A sudden increase of collectivity from {sup 62}Fe to {sup 64}Fe is observed. The experimental results are compared with new large-scale shell-model calculations and Hartree-Fock-Bogolyubov-based configuration-mixing calculations using the Gogny D1S interaction. The results give a deeper understanding of the mechanism leading to an onset of collectivity near {sup 68}Ni, which is compared with the situation in the so-called island of inversion around {sup 32}Mg.
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