This paper provides an overview of the problems, challenges, and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERNs Large Hadron Collider and ...its future upgrade to the High-Luminosity Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates conducted via other tools such as ActiWiz and SESAME, used within the HSE-RP group.
The CERN-MEDICIS (MEDical Isotopes Collected from ISolde) facility has delivered its first radioactive ion beam at CERN (Switzerland) in December 2017 to support the research and development in ...nuclear medicine using non-conventional radionuclides. Since then, fourteen institutes, including CERN, have joined the collaboration to drive the scientific program of this unique installation and evaluate the needs of the community to improve the research in imaging, diagnostics, radiation therapy and personalized medicine. The facility has been built as an extension of the ISOLDE (Isotope Separator On Line DEvice) facility at CERN. Handling of open radioisotope sources is made possible thanks to its Radiological Controlled Area and laboratory. Targets are being irradiated by the 1.4 GeV proton beam delivered by the CERN Proton Synchrotron Booster (PSB) on a station placed between the High Resolution Separator (HRS) ISOLDE target station and its beam dump. Irradiated target materials are also received from external institutes to undergo mass separation at CERN-MEDICIS. All targets are handled via a remote handling system and exploited on a dedicated isotope separator beamline. To allow for the release and collection of a specific radionuclide of medical interest, each target is heated to temperatures of up to 2,300°C. The created ions are extracted and accelerated to an energy up to 60 kV, and the beam steered through an off-line sector field magnet mass separator. This is followed by the extraction of the radionuclide of interest through mass separation and its subsequent implantation into a collection foil. In addition, the MELISSA (MEDICIS Laser Ion Source Setup At CERN) laser laboratory, in service since April 2019, helps to increase the separation efficiency and the selectivity. After collection, the implanted radionuclides are dispatched to the biomedical research centers, participating in the CERN-MEDICIS collaboration, for Research & Development in imaging or treatment. Since its commissioning, the CERN-MEDICIS facility has provided its partner institutes with non-conventional medical radionuclides such as Tb-149, Tb-152, Tb-155, Sm-153, Tm-165, Tm-167, Er-169, Yb-175, and Ac-225 with a high specific activity. This article provides a review of the achievements and milestones of CERN-MEDICIS since it has produced its first radioactive isotope in December 2017, with a special focus on its most recent operation in 2020.
FLUKA is a general purpose Monte Carlo code capable of handling all radiation components from thermal energies (for neutrons) or 1
keV (for all other particles) to cosmic ray energies and can be ...applied in many different fields. Presently the code is maintained on Linux. The validity of the physical models implemented in FLUKA has been benchmarked against a variety of experimental data over a wide energy range, from accelerator data to cosmic ray showers in the Earth atmosphere. FLUKA is widely used for studies related both to basic research and to applications in particle accelerators, radiation protection and dosimetry, including the specific issue of radiation damage in space missions, radiobiology (including radiotherapy) and cosmic ray calculations.
After a short description of the main features that make FLUKA valuable for these topics, the present paper summarizes some of the recent applications of the FLUKA Monte Carlo code in the nuclear as well high energy physics. In particular it addresses such topics as accelerator related applications.
A comprehensive study of the radiological CNGS (CERN Neutrinos to Gran Sasso Experiment) environment characterization is presented. It comprises the evaluation of the residual dose rates of the most ...relevant standalone beam line equipment, such as the target and horn, as well as overall dose levels in the cavern before and after dismantling. Furthermore, the radionuclide inventories of the main objects to be dismantled were calculated by the Monte Carlo FLUKA code and ActiWiz. The latter is particularly important for transport and waste management. Moreover, we present benchmarking measurements of residual dose rates in the experimental cavern, staying in good agreement with simulation predictions. Additional measurements, as well as FLUKA and ActiWiz studies, allowed for assessing the concrete composition of the cavern's walls and floor and the shielding blocks. The resulting refined composition allowed for evaluating more precisely the radionuclide inventories and residual dose rates expected before and after the dismantling in the CNGS target area. This was particularly important for the evaluation of the dismantling cost and the substantial savings due to the reusage of the majority of the concrete blocks. Finally, contamination measurements in the accessible parts of the area also are included. All the results discussed are crucial for determining the requirements, planning, and costs of the CNGS dismantling.
Abstract
In the context of the so-called Long Shutdown 3 (2026–2028), the Large Hadron Collider will be upgraded to the High-Luminosity Large Hadron Collider, allowing for approximately five more ...instantaneous collisions. The upgrade, maintenance and decommissioning of equipment will be mainly performed in the experimental insertions of Points 1 and 5, requiring to perform multiple interventions in high-residual radiation environment. This poses complex radiological challenges that the CERN Radiation Protection group is called to address. Radiation protection studies are performed to plan and optimise (ALARA) these future interventions using the advanced Monte Carlo techniques and tools such as FLUKA, ActiWiz, SESAME and the FCC method. This paper aims to provide an overview of the studies conducted to estimate the residual radiation field in the experimental insertions, the activation levels in terms of multiple of the Swiss clearance limits/specific activity and to provide preliminary considerations on the upgrade/decommissioning of key equipment.
The paper provides an overview of the radiation protection challenges and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERN, particularly with ...regard to the Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates obtained via several tools, used within the CERN Radiation Protection group, such as ActiWiz, SESAME, and the Fluence Conversion Coefficients (FCC) method which extend the built-in FLUKA capabilities. The paper covers the general Radiation Protection principles and rules in force at CERN, the simulation tools/techniques used to fulfill operational tasks and predictive studies, and a set of case studies covering relevant applications at the Large Hadron Collider machine and experiments.
•Advanced and reliable simulation tools are essential in modern Radiation Protection.•FLUKA is widely used at CERN for radiation protection studies at the LHC complex.•Simulation tools such as SESAME, FCC and ActiWiz extend FLUKA built-in capabilities.•RP studies of the upgrade of the LHC are mainly based on advanced simulation tools.•Real-case applications and examples are provided in the paper.
A
bstract
Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, ...generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate.
The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between
O
(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL’s benchmark models and provide a way to calculate the SHiP’s sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.
Maintenance activities and operations of high-energy particle accelerators can lead to the collection of radioactive equipment as well as waste materials. In order to ensure their proper ...classification as radioactive or non-radioactive, one has to quantify the activities of radionuclides produced. According to the regulatory requirements in Switzerland, these activities need to be compared with nuclide-specific clearance limits. In particular, a new set of clearance limits was introduced by the Swiss authorities in January 2018, leading to more conservative values for a number of relevant radionuclides. We describe in this paper a new methodology based on dose-rate measurements to classify potentially radioactive objects at the exit of the CERN accelerator complex. This methodology concerns the specific material compositions typically found at CERN and takes into account the latest clearance limits introduced by the Swiss authorities.
•Classification of radiological objects with dose-rate measurement.•New methodology for clearance of radiological objects.•Classification of radiological objects at the exit of accelerators using calculation codes.
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