Activation experiment at the H4IRRAD facility: A comparison between experimental data, FLUKA and ActiWiz predictions after 15 days of cooling time

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Abstract

An experiment was carried out in June 2011 at the H4IRRAD facility, which allows to reproduce the radiation fields commonly encountered in the CERN Large Hadron Collider. The purpose of this study was to create a set of experimental activation data that can be used to benchmark Monte Carlo codes and now the analytical ActiWiz software package, both extensively used by CERN’s Radiation Protection Group. The choice of actual specimens that have been used for the construction of the Large Hadron Collider (LHC) and the LHC experiments has been made specifically in view of future upgrades or dismantling of CERN’s accelerators and experimental areas. Six samples of materials commonly used at CERN were irradiated by the secondary particles generated from the impact of a 280 GeV/c hadron beam on a 100 cm long copper target with the samples having been placed few centimetres below. This paper discusses first the experimental results obtained by γ-spectrometry measurements after 15 days of cooling time. Then, it discusses the FLUKA simulations performed in order to obtain the radionuclide inventories as well as the mixed particle fluence spectra in the samples. Third, it discusses the predictions by the ActiWiz software and compares them with the FLUKA results for the sake of a code comparison. Finally, the experimental and computational results are compared and discussed altogether.

Section snippets

Introduction and motivation

In June 2011 an activation experiment was carried out at the H4IRRAD facility at CERN by irradiating a set of material samples commonly used at CERN accelerators. The aim was to create a set of experimental activation data that can be used to benchmark Monte Carlo codes and now the analytical ActiWiz software package, both extensively used by CERN’s Radiation Protection Group, with actual specimens that have been used for the construction of the Large Hadron Collider (LHC) and the LHC

Experimental set-up and irradiation

The experiment took place at CERN at the H4IRRAD facility, located in the H4 beam line in the CERN’s North Experimental Area. H4IRRAD is an irradiation area which has been built to test the radiation effects on LHC electronic equipment and allows for a reproduction of the radiation field present in the LHC tunnel and its shielded areas [1]. It uses a secondary 280 GeV/c positive hadron beam originating from the impact of the 400 GeV/c primary proton beam of the Super Proton Synchrotron (SPS) on

Tools and goals

Using the FLUKA code (version 2011.2x.0) [20], [21], [22] the geometry of the experimental set-up within the H4IRRAD facility was fully implemented. Simulating the interaction of the secondary 280 GeV/c mixed particle beam with the copper target allowed, on one hand, for directly obtaining the radionuclide inventories for specified irradiation and cooling periods as well as the particle fluence within each sample material. The latter serves as an input for ActiWiz Creator (version 3.4) [23] in

Conclusions

In 2011, an activation experiment was carried out in the H4IRRAD facility, located in the H4 secondary beam line, North Experimental Area, of the CERN Super Proton Synchrotron. The aim of this study was to benchmark the nuclide inventory predicted by the FLUKA Monte Carlo code against measurements on different material samples. These samples were exposed to the stray radiation field generated by a mixed hadron beam of 280 GeV/c impinging on a 100 cm long copper target. The samples were chosen

CRediT authorship contribution statement

Charlotte Duchemin: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Writing - original draft, Writing - review & editing, Visualization. Francesco La Torre: Conceptualization, Methodology, Investigation, Writing - review & editing. Matteo Magistris: Supervision, Writing - review & editing. Marco Silari: Supervision, Project administration, Writing - review & editing.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors would like to thank the EN department for providing beam time at the H4IRRAD facility and all people who contributed to the success of the experiment. The authors would like to express their gratitude towards every person within the RP group involved in the dose rate measurements, arranging transportation towardsthe CERN RP γ-spectrometry laboratory and performing the γ-spectrometry measurements. We would like to thank C. Theis and H. Vincke for providing information and advice on

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