Analysis of the Photoneutron Field Near the THz Dump of the CLEAR Accelerator at CERN With SEU Measurements and Simulations

Giuseppe Lerner,Antonio Gilardi,Daniel Prelipcean,Roberto Corsini,Andrea Coronetti,Wilfrid Farabolini,Ruben Garcia Alia,Jean Mael Kempf,Francesco Cerutti,Matteo Cecchetto

doi:10.1109/tns.2022.3157404

Abstract

We study the radiation environment near the terahertz (THz) dump of the CERN Linear Electron Accelerator for Research (CLEAR) electron accelerator at CERN, using FLUktuierende KAskade in German (FLUKA) simulations and single-event upset (SEU) measurements taken with 32-Mbit Integrated Silicon Solution Inc. (ISSI) static random access memories (SRAMs). The main focus is on the characterization of the neutron field to evaluate its suitability for radiation tests of electronics in comparison with other irradiation facilities. Neutrons at CLEAR are produced via photonuclear reactions, mostly initiated by photons from the electromagnetic cascades that occur when the beam is absorbed by the dump structure. Good agreement is generally found between the measured single-event upset (SEU) rates and the expected values obtained from FLUKA simulations and the known SEU response of the ISSI SRAMs to neutrons, while one position is found to be potentially affected by photon-driven SEUs.

Highlights

The CERN Linear Electron Accelerator for Research (CLEAR) [1] provides electron beams with energies in the 55-220 MeV range, allowing access from both CERN and external users for many applications
The main highlight of this work is the experimental confirmation of the presence of a significant neutron field near the CLEAR THz dump, suitable for Single Event Upsets (SEUs) measurements with Static Random Access Memories (SRAMs)
The neutron energy spectrum extends from thermal to high energies with a peak around 1 MeV, such that the High Energy Hadron (HEH)-eq flux is dominated by intermediateenergy neutrons, implying that the SEU rates are affected

Summary

Introduction

The CERN Linear Electron Accelerator for Research (CLEAR) [1] provides electron beams with energies in the 55-220 MeV range, allowing access from both CERN and external users for many applications. In the context of radiation effects to electronics (R2E), direct in-beam irradiations at CLEAR have been used to show that high-energy electrons can induce Single Event Upsets (SEUs) [2], latchups [3] and stuck bits [4] in memories. The goal of the study, which uses Monte Carlo simulations and SEU measurements with Static Random Access Memories (SRAMs) [6], is to examine the neutron field properties (flux, energy spectrum) verifying its suitability for radiation testing of devices to be used in present and future CERN accelerators [7, 8] and beyond (e.g. medical applications [9]). While obviously the CLEAR radiation field is expected to differ from the one of CHARM, where a 24-GeV proton beam is used, the CLEAR facility presents a number of advantages, linked in particular to the ease of accessing it (CLEAR is a standalone machine, unlike CHARM which is part of the CERN accelerator complex and is bound to its operation) and to the flexibility that it offers in terms of beam properties and parameters (e.g. energy, intensity, time structure)

Methods

Results

Conclusion