Project Details
Projekt
Background Analysis and Background Control
Applicant
Professor Dr. Josef Jochum
Subject Area
Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
Term
from 2015 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 254114301
In the upcoming phase of the ECHo experiment, ECHo-100k, we aspire to reach a sensitivity below 2 eV on the mass of the neutrino. To achieve this sensitivity, a background index of less than 10-6 events/d/det/eV around the region of interest around QEC = 2.833 keV is required, only one tenth of the background allowed in the ECHo-1k phase. This demands an improved knowledge and control of the background. The radiopurity of the materials used in the ECHo experiment is determined with Hp-Ge detectors. The impact of the identified sources on the spectrum seen in the detectors is then investigated by Monte Carlo simulations of the experimental setup and the resulting background spectra are used to predict the expected background. An additional source of background are cosmogenic muons which produce secondary particles which may deposit energy in the detectors. This background is suppressed with an active muon veto. The efficiency of the muon veto and the spectrum of the unvetoed events are investigated with Monte Carlo simulations. The specific challenge for ECHo-100k is given by the very low energy of the region of interest (<3 keV), the tiny size of the detector elements and the large number of single pixels. These features require a thorough validation and improvement of the simulation framework used. From the experience of other low background experiments, it is expected to encounter additional background from physical processes which are currently not considered in the background model. Working group 4 has four objectives in the upcoming ECHo-100k phase:(I) The validation and improvement of the background model for the ECHo-100k phase. This encompasses the analysis of the observed background from the ECHo-1k phase, the modification of the background model to account for the lessons learnt and the re-simulation of the background with the new ECHo-100k geometry and the improved physics models. At the end, a prediction of the background in the upcoming phase of the ECHo experiment is made. (II) The improvement and modification of the used Monte Carlo simulation suite for the requirements of the ECHo-100k phase. This is necessary to implement improved physics processes and to efficiently implement the large scale detector setup. (III) The operation and upgrade of the muon veto. It is planned to change the read out electronics of the muon veto panels to a micro-controller based design to harden it against RF-noise and allow for a more streamlined DAQ and control of the muon veto panels. Furthermore, a compact, cryogenic veto system is going to be developed to reduce background from cosmogenics and from possible contaminations of the experimental environment of the cryostat decisively. (IV) An extended screening campaign of the materials and parts used in the experiment with the HP-Ge detector at the UGL in Tübingen in order to collect the data on the radio-contamination of the ECHo-100k setup and use the obtained data in the background model.
DFG Programme
Research Units
