Neutron Veto Inefficiency Studies with FLUKA for the LDMX Hadronic Calorimeter
(2023) FYSK03 20231Particle and nuclear physics
Department of Physics
- Abstract
- Dark matter accounts for about 85% of all matter in the Universe, yet its particle nature remains unknown. The Light Dark Matter eXperiment (LDMX) is a proposed fixed-target missing-momentum experiment that intends to probe the predominantly experimentally uncharted MeV-GeV mass range for "light dark matter". A significant challenge for LDMX is to efficiently veto rare photo-nuclear background events resulting in high energy (∼3 GeV) neutral hadrons. The preliminary design of the sampling hadronic calorimeter (HCal), which is responsible for detecting neutral hadrons and consists of alternating layers of steel absorber plates and polystyrene scintillator bars, has been developed using GEANT4 simulations to realise the required veto... (More)
- Dark matter accounts for about 85% of all matter in the Universe, yet its particle nature remains unknown. The Light Dark Matter eXperiment (LDMX) is a proposed fixed-target missing-momentum experiment that intends to probe the predominantly experimentally uncharted MeV-GeV mass range for "light dark matter". A significant challenge for LDMX is to efficiently veto rare photo-nuclear background events resulting in high energy (∼3 GeV) neutral hadrons. The preliminary design of the sampling hadronic calorimeter (HCal), which is responsible for detecting neutral hadrons and consists of alternating layers of steel absorber plates and polystyrene scintillator bars, has been developed using GEANT4 simulations to realise the required veto inefficiency. To validate the GEANT4 results, it was thus of interest and the aim of this project to perform a comparative study of neutron veto inefficiency between GEANT4 and other Monte Carlo codes, in this case FLUKA. By modelling a simplified LDMX HCal geometry using the FLUKA Advanced InteRface (FLAIR) the neutron veto inefficiency as a function of HCal depth was found. This was done for 0.1 GeV, 0.5 GeV, 1.0 GeV and 3.0 GeV incident neutrons with a threshold of 1 MeV and 10 MeV. Results indicate that FLUKA and GEANT4 are comparatively similar and independent of the thresholds. This indicates that the current design of the HCal with a depth of ∼3 m, is sufficient so as to ensure the veto performance for the relevant photo-nuclear backgrounds. (Less)
- Popular Abstract
- All matter we know and see only accounts for a mere 15% of all matter in the Universe. The remaining 85% is known as "dark" matter since it does not interact electromagnetically and is thus invisible. Only indirect evidence for dark matter exists in the form of gravitational interactions with visible matter. By finding out what constitutes dark matter, insight into the fundamental structure and evolution of the Universe may be revealed.
One proposed experiment is the Light Dark Matter eXperiment (LDMX) that intends to probe for dark matter particles with low mass. The LDMX aims to do this by directing high energy electrons on a fixed tungsten target, resulting in the electrons scattering off the target and in a rare process could... (More) - All matter we know and see only accounts for a mere 15% of all matter in the Universe. The remaining 85% is known as "dark" matter since it does not interact electromagnetically and is thus invisible. Only indirect evidence for dark matter exists in the form of gravitational interactions with visible matter. By finding out what constitutes dark matter, insight into the fundamental structure and evolution of the Universe may be revealed.
One proposed experiment is the Light Dark Matter eXperiment (LDMX) that intends to probe for dark matter particles with low mass. The LDMX aims to do this by directing high energy electrons on a fixed tungsten target, resulting in the electrons scattering off the target and in a rare process could produce dark matter particles. Since dark matter particles escape detection they are hence only quantifiable by the missing energy and momentum. However, it is more likely that Standard Model processes occur instead. It is therefore crucial for the LDMX to differentiate between processes that actually result in dark matter versus those that do not. Processes that do not result in dark matter then need to be efficiently vetoed by the detector. A key challenge for LDMX is to efficiently veto the process that results in single high energy neutrons.
Using simulations, the design of the sub-detector responsible for identifying neutrons has been optimised to a high degree of efficiency in order to veto single high energy neutrons. To ensure that the results acquired from previous simulations are accurate, it was of interest and the aim of this project to perform a comparative study using a competing simulation tool known as FLUKA.
This project found that there was little difference between the two simulation tools, and concludes that current LDMX sub-detector design considerations are likely to provide sufficient sensitivity and efficiency to veto single high energy neutrons. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9121371
- author
- Raffelsberger, Jaida
- supervisor
- organization
- course
- FYSK03 20231
- year
- 2023
- type
- M2 - Bachelor Degree
- subject
- language
- English
- id
- 9121371
- date added to LUP
- 2023-06-08 17:02:31
- date last changed
- 2023-06-09 16:07:20
@misc{9121371,
abstract = {{Dark matter accounts for about 85% of all matter in the Universe, yet its particle nature remains unknown. The Light Dark Matter eXperiment (LDMX) is a proposed fixed-target missing-momentum experiment that intends to probe the predominantly experimentally uncharted MeV-GeV mass range for "light dark matter". A significant challenge for LDMX is to efficiently veto rare photo-nuclear background events resulting in high energy (∼3 GeV) neutral hadrons. The preliminary design of the sampling hadronic calorimeter (HCal), which is responsible for detecting neutral hadrons and consists of alternating layers of steel absorber plates and polystyrene scintillator bars, has been developed using GEANT4 simulations to realise the required veto inefficiency. To validate the GEANT4 results, it was thus of interest and the aim of this project to perform a comparative study of neutron veto inefficiency between GEANT4 and other Monte Carlo codes, in this case FLUKA. By modelling a simplified LDMX HCal geometry using the FLUKA Advanced InteRface (FLAIR) the neutron veto inefficiency as a function of HCal depth was found. This was done for 0.1 GeV, 0.5 GeV, 1.0 GeV and 3.0 GeV incident neutrons with a threshold of 1 MeV and 10 MeV. Results indicate that FLUKA and GEANT4 are comparatively similar and independent of the thresholds. This indicates that the current design of the HCal with a depth of ∼3 m, is sufficient so as to ensure the veto performance for the relevant photo-nuclear backgrounds.}},
author = {{Raffelsberger, Jaida}},
language = {{eng}},
note = {{Student Paper}},
title = {{Neutron Veto Inefficiency Studies with FLUKA for the LDMX Hadronic Calorimeter}},
year = {{2023}},
}