Electron spectrometry with Silicon drift detectors: a GEANT4 based method for detector response reconstruction

Abstract

Precision electron spectrometry in the keV range has always been considered a challenging task. The reconstruction of the original electron energy from the detected signal is not trivial because multiple effects modify the kinetic energy of the electron along its path. If not correctly accounted for, these effects can spoil and bias the reconstructed energy with a dramatic reduction of accuracy and precision. In this paper we address one of the most critical aspects of electron spectrometry: the generally unknown effect of the detector entrance window. We show that, with a MonteCarlo-based approach, we are able to build a model of the entrance window accurate enough to reduce the negative effects due to its existence. We adopt for this purpose Silicon Drift Detectors that, thought primarily used for X-ray spectrometry, appear a promising device for electron spectrometry. The technique we discuss exploits characterization and validation measurements performed with electron beams from a Scanning Electron Microscope, later reconstructed with a GEANT4 MonteCarlo simulation.

KATRIN: Status and Prospects for the Neutrino Mass and Beyond

“…Here, we present first characterization measurements of a 7 −pixel prototype SDD with monoenergetic electrons at room temperature [142,144,145]. A scanning electron microscope was used as a calibration source.…”

“…More details on the electron characterization measurements can be found in Ref. [142,144,145], including an estimation of the entrance-window thickness, as well as the impact of the detector response on the sterile neutrino sensitivity.…”

“…To test the general performance of the novel detector system, several measurements were performed with 1-, 7-and 47-pixel prototype detectors in dedicated setups [142][143][144][145]. In particular, we investigated the energy resolution, linearity, and electronic noise of the system.…”

KATRIN: status and prospects for the neutrino mass and beyond

“…To test the general performance of the novel detector system, several measurements were performed with 1-, 7-and 47-pixel prototype detectors in dedicated setups [144][145][146][147]. In particular, we investigated the energy resolution, linearity, and electronic noise of the system.…”

Development of cryogenic calorimeters to measure the spectral shape of In-115 beta decay

“…The same issues affect also the most advanced tool for electron spectroscopy, i.e. Silicon Drift Detector [11], even if recent results demonstrate the possibility to include these effects in the Monte Carlo simulations [12]. On the other hand, cryogenic macro-calorimeters have recently been used for the first time to study the spectral shape of the two-neutrino double-beta decay [13,14,15],demonstrating their potential for this application.…”