Unique particle beams and energies at CERN applied to radiation testing of

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Unique particle beams and energies at CERN applied to radiation testing of

electronics

PhD Thesis

Vanessa Wyrwoll

Department of Physics University of Oslo

April 2022

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Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission.

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Declaration on own contribution

I hereby declare that the work presented in this thesis has not been submitted for any other degree or professional qualification, and that it is the result of my own independent work. In the following I describe my own contribution to the included Papers:

Paper 1: Heavy ion nuclear reaction impact on SEE testing: From standard to Ultra-high energies

Paper 2: Longitudinal Direct Ionization Impact of Heavy Ions on SEE Testing for Ultra-high Energies

Paper 3: On-line beam monitoring and dose profile measurements of a ²⁰⁸Pb beam of 150 GeV/n with a liquid-filled ionization chamber array

Paper 4: Pulsed Electron Beam induced SEU Effects in a SRAM memory Simulations

The Monte Carlo simulation tool FLUKA2011 Version 2x.6 Mar-19 has been used by me for all simulations included in this thesis. I have performed all FLUKA simulations in Paper 1, 2 and 3. To do this, I have built the needed input files and geometries, run them on the cluster and performed the analysis of the data. In section 3.4 the use of FLUKA in this work is further described.

Experiments

The data points presented in Paper 1 include experimental data from various test campaigns at UCL and PSI. This data has been retrieved by the R2E group at CERN, before I started my PhD in 2017. Moreover, two data points have been collected in experiments at CHARM (CERN) during the heavy ion runs in the LHC using a 40 GeV/n xenon beam in 2017 and using a 150 GeV/n lead beam in 2018, where I participated in as part of the R2E working group.

These Ultra-high Energy (UHE) heavy ion beams have not only been delivered to CHARM, but also to the Super Proton Synchrotron (SPS) experimental North Area (NA). There, the experimental data I used in Paper 2 has been collected 2018 by Carlo Cazzaniga, using the 150 GeV/n lead beam. I helped organizing and managing the test campaign as part of the R2E team.

All experiments included in Paper 3 and 4 have been planned, organized and performed by me.

In section 3.5, these experiments are described in more detail for all four Papers.

Data Post Processing

The general post processing of all the retrieved data, both via simulation and experiment in all four Papers, has been carried out by me. For this purpose, depending on the analytical needs, I have written Matlab and Python scripts or made use of Excel. With this processed data, I have written the manuscripts that led to the included Papers.

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Preface

This thesis is submitted in partial fulfilment of the requirements for the degree of Philosophiae Doctor at the University of Oslo. The research presented here was conducted at the University of Oslo and at CERN, under the supervision of Ketil Røed, Co- supervisor Rubén García Alía, Arto Javanainen, Frédéric Wrobel and Björn Poppe. This work has been done in the frame of the Marie Curie Network project RADSAGA and was supported by the European Union’s Horizon 2020 Research Innovation Program under the Grant Agreement no. 721624. The thesis is a collection of four Papers, presented in chronological order of writing. The Papers are preceded by an introductory chapter that relates them together and provides background information and motivation for the work.

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Abstract

The radiation environment in space poses unique challenges to the successful operation of electronic components exposed to it. Hence, it is important to test the devices sufficiently before integrating them in space missions. Even better to do so already during their design phase. Likewise, radiation effects on electronics also represent reliability and availability threats for high-energy accelerator applications.

The work performed in the frame of this thesis focuses on the investigation of beams mimicking space and accelerator environments. Radiation such as Ultra-High Energy (UHE) heavy ions and Very High Energy (VHE) electrons play an important role in this context. Since UHE heavy ions are mostly present in the Galactic Cosmic Radiation (GCR) environment and electrons are mostly trapped around planets such as the Earth and Jupiter, their interaction with matter and the resulting radiation effects are of special interest.

Aspects such as nuclear fragmentation and energy deposition mechanisms are relevant when estimating the possible impact on electronic components of radiation present in space or on the ground. Hence, tests have been performed to study this response to the radiation exposure particle types in dedicated test facilities. During such experiments, the dosimetry and beam parameters must be in full control.

UHE heavy ion test campaigns and experiments with VHE electrons at CERN have served as an excellent opportunity to investigate the interaction with matter of various particle species and energies similar to the GCR and electron-rich environments in space, such as around Jupiter. Due to their high penetration depth, one of the advantages of UHE heavy ion beams at CERN is to test without decapsulation. Moreover, these beams offer the opportunity to work with particles of identical Linear Energy Transfer (LET) and energies to the ones in space. That is interesting, because on the contrary it is a well- established standard to perform radiation tests for space applications with low energy heavy ions.

With regards to high-energy electrons, the implications of an exponential increase in Single Event Effects (SEEs) connected to testing at a high instantaneous electron flux [1]

and the resulting nuclear electron processes [2] need to be considered. These observations deserve to be characterised and understood, even if they might represent an experimental artefact.

For these reasons, the central research questions in this work are:

- Is testing with particles of the same LET, but different energy compared to the space environment representative enough?

- How can electron beams at CERN be used to test electronics for future space missions, which will be exposed to electron-rich environments? Are there non- linear effects related to high instantaneous intensities of electron fluxes by changing the charge density per pulse?

This work has contributed to the understanding of physical phenomena occurring in electronics caused by radiation present in space and in accelerators environments, such as fusion and nuclear fragmentation processes and energy deposition in different materials and volumes. Ground level experimental work in related particle beams, as well as Monte Carlo simulations tools like FLUKA have served for the investigations presented in this PhD thesis.

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List of Publications

Papers included in this work:

Paper 1:

Wyrwoll V, García Alía R, Røed K, Fernández-Martínez P, Kastriotou M, Cecchetto M, Kerboub N, Tali M, Cerutti F. Heavy ion nuclear reaction impact on SEE testing: From standard to Ultra-high energies.

IEEE Transactions on Nuclear Science. 2020 Feb 12; 67 (7):1590-8.

Paper 2:

Wyrwoll V, García Alía R, Røed K, Cazzaniga C, Kastriotou M, Fernández-Martínez P, Coronetti A, Cerutti F. Longitudinal Direct Ionization Impact of Heavy Ions on SEE Testing for Ultra-high Energies.

IEEE Transactions on Nuclear Science. 2020 May 14; 67 (7):1530-9.

Paper 3:

Wyrwoll V, Delfs B, Lapp M, Poppinga D, Martinéz PF, Kastriotou M, García Alía R, Røed K, Gerbershagen A, Looe HK, Poppe B. On-line beam monitoring and dose profile measurements of a 208Pb beam of 150 GeV/n with a liquid-filled ionization chamber array. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment; 987:164831.

Paper 4:

Wyrwoll V, Røed K, García Alía R, Delfs B, Coronetti A, Farabolini W, Gilardi A, Corsini R. Pulsed Electron Beam induced SEU Effects in a SRAM memory. Conference Proceeding RADECS 2021

Papers not included but relevant to this work:

Poppinga D, Kranzer R, Farabolini W, Gilardi A, Corsini R, Wyrwoll V, Looe HK, Delfs B, Gabrisch L, Poppe B. VHEE beam dosimetry at CERN Linear Electron Accelerator for Research under ultra-high dose rate conditions. Biomedical Physics & Engineering Express. 2020 Nov 16.

Kastriotou M, Fernandez-Martinez P, García Alía R, Cazzaniga C, Cecchetto M, Coronetti A, Lerner G, Tali M, Kerboub N, Wyrwoll V, Bernhard J. Single Event Effect Testing with Ultra-high Energy Heavy Ion Beams. IEEE Transactions on Nuclear Science. 2019 Dec 23; 67 (1): 63-70.

Fernández-Martínez P, García Alía R, Cecchetto M, Kastriotou M, Kerboub N, Tali M, Wyrwoll V, Brugger M, Cangialosi C, Cerutti F, Danzeca S. SEE tests with ultra-energetic Xe ion beam in the CHARM facility at CERN. IEEE Transactions on Nuclear Science. 2019 Mar 25; 66 (7): 1523-31.

García Alía R, Fernández-Martínez P, Kastriotou M, Brugger M, Bernhard J, Cecchetto M, Cerutti F, Charitonidis N, Danzeca S, Gatignon L, Gerbershagen A. Ultra-energetic heavy-ion beams in the CERN accelerator complex for radiation effects testing. IEEE Transactions on Nuclear Science. 2018 Nov 28; 66 (1): 458-65.

García Alía R, Tali M, Brugger M, Cecchetto M, Cerutti F, Cononetti A, Danzeca S, Esposito L, Fernández- Martínez P, Gilardoni S, Infantino A. Direct Ionization Impact on Accelerator Mixed field Soft-Error Rate.

IEEE Transactions on Nuclear Science. 2019 Nov 4; 67 (1): 345-52.

Cazzaniga C, Kastriotou M, Alía RG, Fernandez-Martinez P, Wyrwoll V, Minniti T, Frost CD.

Measurements of ultra-high energy lead ions using silicon and diamond detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment; 985:164671.

Furano G, Tavoularis A, Santos L, Ferlet-Cavrois V, Boatella C, Alia R G, Martinez P F, Kastriotou M, Wyrwoll V, Danzeca S, Tali M. FPGA see test with ultra-high energy heavy ions. In 2018 IEEE International Symposium on Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT) 2018 Oct 8 (pp. 1-4). IEEE.

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Acknowledgements

The work done in the frame of this PhD thesis was supported by the RADiation and reliability challenges for electronics used in Space, Avionics, on the Ground and at Accelerators (RADSAGA) funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant 721624.

I would like to thank everyone who helped me during my PhD. There have been so many people, who have shared this path with me. I cannot find words for my appreciation to every one of you. All my colleagues, at CERN, in Oldenburg, in Oslo, within the RADSAGA project and my co-authors and beyond that. You have all contributed not only on a professional level, but also socially to this PhD project being finished successfully.

A special thanks to my main supervisors, Rubén García Alía and Ketil Røed. You have been my mentors not only professionally, but also personally. The concept of my PhD was, to be in both places, Oslo and CERN. This, I could manage due to your support. I always knew, your door or your post box, is open for every question I had. Even if we have had tough conversations and the stress level was high, due to deadlines, experiments or a full schedule, you have never let me down.

Moreover, to my co-supervisors Arto Javaneinen and Frédéric Wrobel, thank you for all the valuable input and discussions during this time.

To Carlo Cazzaniga and Wilfrid Farabloni. Your expertise has greatly contributed to the success of my experiments. Your competence is outstanding.

To my colleagues and friends, Ygor Aguiar and Sascha Lüdeke. For being there during our RADSAGA time. With you, every summer school, workshop or conference has been a memorable event.

To my former working group in Oldenburg, especially Hui Khee Looe and professor Björn Poppe. For all the fruitful discussions and work, even after I left the group to join RADSAGA. I am so thankful for that.

To my colleagues at CERN, the FLUKA development team and the R2E group. Thanks to the work we have performed together, my learning curve has been exponential during my time at CERN.

To my office mates at CERN, Andrea Coronetti and Nourdine Kerboub. I will never forget how Nourdine, from the South of France and me, from North of Germany, have tried to find a consent about the window opening time or room temperature. Or the moment you talked to me in French and I answered in German, without realizing, due to a lot of work and a tough dead line at that time. Andrea, with whom I had a lot of conversations and laughs during experiments and office hours. Thank you two for all the moments we have shared.

To my family and friends at home, you have always had my back.

Lastly, I would like to thank Björn. The whole time, you have been my anchor.

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List of Figures

Fig. 1. Cross-section of the SEU monitor versus heavy ion LET at the facilities RADiation Effects Facility (RADEF) with 9.3 MeV/u, Texas A&M University (TAMU) with 25 MeV/u, Gesellschaft für

Schwerionenforschung (GSI) with 100 to 1000 MeV/u. For RADEF and TAMU, the full and open symbols correspond to normal incidence and tilted angles (45 and 60 degrees). The results around 1.8

MeVcm²/mg are emphasized using a rectangle. Picture taken from [11]. ... 18

Fig. 2. Correlation between radiation sources in space and the effects on electronic components. Picture taken from [15]. ... 20

Fig. 3. Van-Allen radiation belts of the Earth and the fluence rates of the protons and electrons in cm-2 s- 1 taken from [13]... 21 Fig. 4. Illustration of particle composition in space. Data taken from [14]. ... 22

Fig. 5. The energy spectrum of hydrogen, helium, oxygen, and iron of the GCR environment during a minimum and maximum of a solar cycle. Picture from [14]. ... 23 Fig. 6. Effective LET illustration. ... 26

Fig. 7. Unrestricted (lines) and volume equivalent LET (crosses). The solid lines are calculated by Stopping and Range of Ions in Matter (SRIM), the dashed lines via FLUKA. Picture taken from [33]. ... 27

Fig. 8. Experimentally retrieved deposited energy distribution of 150 GeV/n lead in a 140 µm silicon detector during the test campaign 2018 in the North Area (NA) at CERN. Picture taken from Paper 2. ... 28

Fig. 9. Illustration of simulated xy-planes. Showing the track segments of delta-ray electrons simulated with RITRACKS for different ions and different energies (MeV/u). Picture taken from [37]. ... 29 Fig. 10. Illustration of indirect ionization processes. ... 30

Fig. 11. Illustration of the TID process caused by incident radiation (red arrows) on a component and the created electron-hole pairs within the target material. ... 31

Fig. 12. Illustration of the DD origin process, when an incident projectile (red) hits an atom within the target atom grid and causes it to leave its place in the material. ... 32

Fig. 13. Example of a FLUKA input of used beam parameters in Paper 1, 2 and 3 and the needed beam definition. Screenshot taken from FLAIR [47]. ... 36

Fig. 14. Example of a FLUKA input used for body definition purposes in Paper 3. Screenshot taken from FLAIR [47]. ... 37

Fig. 15. Example of a FLUKA input used for region definition purposes in Paper 3. Screenshot taken from FLAIR [47]. ... 37

Fig. 16. Example of a FLUKA input used for assignment definition purposes in Paper 3. Screenshot taken from FLAIR [47]. ... 37 Fig. 17. Exemplary FLUKA input of SEL RPP modelling. Screenshot taken from FLAIR [47]. ... 38 Fig. 18. Schematic sketch of the cross-section concept. Picture taken from [53]. ... 38

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Fig. 19. This card is used to define a RPP (rectangular parallel piped) volume named CV1 with dimensions extending from Xmin to Xmax, Ymin to Ymax, and Zmin to Zmax, where the beam direction is along the z axis. Units are in cm in FLUKA. This geometry was used in Paper 1. Screenshot taken from FLAIR [47]. .. 39

Fig. 20. Cut in the xz plane of the 2 mm × 2 mm × 140 µm silicon RPP model used in the fusion, fission, nuclear interaction investigations and simulations of LET and deposited energy in Paper 1 and Paper 2.

The blue arrow shows the beam position on the left side along the z axis. Screenshot taken from FLAIR [47]. ... 39

Fig. 21. Cut in the xz plane of the RPP model used in the SEL simulation of Paper 1 including the lid. This device has 160 silicon CVs with a size of 1.6·10^-6 µm³. The lid (dimensions: ∆y = 0.035 cm, ∆x = 0. 215 cm,

∆z= 0.003) is filled with vacuum, in orange the target (dimensions: ∆y = 0.035 cm, ∆x = 0. 215 cm, ∆z = 0.0005 cm) can be seen and is made of silicon, this target area is divided by an area filled with tungsten and behind that tungsten layer are the CVs located (green). The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 39

Fig. 22. Cut in the yz plane of the used RPP model in Paper 2. Here a 0.2 cm × 0.2 cm × 140 µm silicon target (orange) is placed behind an aluminium layer (grey) of 0.2 cm × 0.2 cm × 0.5 cm. The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 40

Fig. 23. Cut in the yz plane of the used RPP model in Paper 2. Here a 0.2 cm × 0.2 cm × 140 µm silicon target (orange) is placed behind an air layer (light blue) of 0.2 cm ×0.2 cm ×0.5 cm and an aluminium layer (grey) of 0.2 cm × 0.2 cm × 0.5 cm. The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 40

Fig. 24. 18 Cut in the xz plane of one of the used RPP models in Paper 2. Here a 0.2 cm × 0.2 cm × 140 µm silicon target (orange) is placed behind an aluminium layer (grey) of 1 mm × 1 mm × 1 mm. The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 41

Fig. 25. Cut in the yz plane of one of the used RPP models in Paper 2 to simulate SEUs. Here the SEU detector is simulated with 100 SV of 1 μm³. The target material (orange) and CVs (dark green) are made of silicon. The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 42

Fig. 26. Cut in the yz plane of the simulated Octavius 1000SRS. In green, the Isooctane layer is visible in the zoom. The beam comes from the left side along the z axis, as marked with the blue arrow. Screenshot taken from FLAIR [47]. ... 43 Fig. 27. Exemplary DELTARAY threshold FLUKA input card. Screenshot taken from FLAIR [47]. ... 44

Fig. 28. FLUKA simulation of the energy deposition spectra in a 140 μm silicon detector for 150 GeV/n lead. ... 44 Fig. 29. Exemplary THRESHOLD card input in FLUKA. Screenshot taken from FLAIR [47]. ... 45

Fig. 30. FLUKA simulation of the energy deposition spectra in a 140 μm silicon detector for 150 GeV/n

208Pb comparison between simulation including inelastic interaction and excluding them. ... 45

Fig. 31. Z distribution of 9.3 MeV/n 20 neon, 9.3 MeV/n argon and 200 MeV protons on a 140 µm silicon target taken from Paper 1. ... 47 Fig. 32. LET distribution of 9.3 MeV/n neon on a 140 µm silicon target taken from Paper 1. ... 47

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Fig. 33 Kinetic energy distribution of the fragments with 12.5 < Z < 16.5 generated by 200 MeV protons, 9.3 MeV/n neon, 9.3 MeV/n argon and 150 GeV/n lead ions, impinging on a 140 µm-thick silicon target.

Discussed and taken from Paper 1. ... 48

Fig. 34. Kinetic energy distribution of 9.3 MeV/n neon and 9.3 MeV/n argon on a 140 µm silicon target.

Simulated using FLUKA. ... 49

Fig. 35. Event-by-event energy deposition scoring work flow in. Input cards (blue) and user routines (red).

Picture taken from [22]. ... 51

Fig. 36. Simulated sub-LET SEL cross-section of neon for a SRAM memory (dashed blue) up to 150 GeV/n compared to a simulation after removing all tungsten (red). Taken from Paper 1... 52

Fig. 37. Simulated energy deposition curve of 4 MeV/n neon in silicon normalized to the number of incident beam particles. ... 53 Fig. 38. Integrated simulated energy spectrum of 4 MeV/n neon in silicon. ... 54

Fig. 39. Simplified schematic overview of the CERN accelerator complex highlighting the SPS-North Area, where the experiments in this work have been performed. Picture taken from Paper 3. ... 56 Fig. 40. Schematic overview of the North Area at CERN. Picture taken from Paper 3. ... 57

Fig. 41. CHARMs geometry implemented and used in FLUKA by Fernández-Martínez et al. in [59], representing the experimental hall. The experiments included in this work have been done using a direct beam, hence without a target or shielding inserted. Picture taken from [59]. ... 57

Fig. 42. Calibration curve of all three colour channels for the EBT3 films obtained with 21 MeV electrons.

... 59

Fig. 43. Silicon diode setup during the CNA low energy protons RADSAGA campaign in Centro Nacional de Aceleradores (CNA) in Seville (Spain) [65]. ... 60

Fig. 44. ESA monitor mounted on a plexiglass in front of an Octavius 1000SRS and next to Gafchromic films during the tests at VESPER at CERN. Visible on the right side in detail. Picture taken during the experiments for Paper 4. ... 61

Fig. 45. Readout interface and distribution of SEUs in the ESA monitor, showing that the beam was concentrated on die 1. Snapshot software during the performed experiment in VESPER. Picture taken from Paper 4. ... 61

Fig. 46. Experimental setup using the Samsung SEL memory at CHARM. Data retrieved with this device has been used in Paper 1. ... 62 Fig. 47. Illustration of the chamber arrangement in the 1000SRS, taken from Paper 3. ... 62 Fig. 48. Schematic sketch of an ionization chamber. ... 63

Fig. 49. Octavius 1000SRS liquid ionization chamber array test setup on a tripod. Experiment performed for Paper 3. ... 64

Fig. 50. LET distribution of 9.3 MeV/n 40 Ar fragmentation in a 140 µm silicon target, as obtained from FLUKA Monte Carlo simulations. Picture taken from Paper 1. ... 66 Fig. 51. FLUKA simulated sub-LET for heavy ions and proton SEL cross-section as a function of ion energy for a SRAM memory up to 150 GeV/n compared to experimental data. Picture taken from Paper 1. ... 66

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Fig. 52. FLUKA simulation of the energy deposition spectra in a 140 μm silicon detector for 150 GeV/n lead and increasing aluminium and air thicknesses in front of the SV. ... 68

Fig. 53. Linearity of the integral 1000SRS signals against the corresponding scintillator counts. Picture calculated and taken from Paper 3. ... 69

Fig. 54. 2D illustration of the measurement with the film attached in front of the array (right) and recorded by the array (left). Picture taken from Paper 3. ... 70

Fig. 55. 2D illustration of the measurement with the film attached behind the array (right) and recorded by the array (left). Picture taken from Paper 3. ... 70 Fig. 56. Cross-section for 200 MeV and 56 MeV electrons on an ESA SEU monitor in relation to the charge per train delivered on the device. Picture calculated and taken from Paper 4. ... 71

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List of Tables

Table 1 Short overview of used FLUKA user routines in the frame of an event-by-event energy deposition approach as described in this section. ... 51 Table 2 Overview of performed experiments, which contributed to this thesis. ... 55 Table 3. The main beam parameters for low and high intensity configuration and 5 Hz [60]. ... 58

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List of Abbreviations

CAN Centro Nacional de Aceleradores

CERN Conseil Européen pour la Recherche Nucléaire CHARM CERN High-energy AcceleratoR Mixed field

CLEAR CERN Linear Electron Accelerator for Research facility.

CMOS Complementary Metal Oxide Semiconductor CRAND Cosmic Ray Albedo Neutron Decay

DD Displacement Damage

DUT Device Under Test

ESA European Space Agency

FLUKA Fluktuierende Kaskade

GCR Galactic Cosmic Radiation

Gy Gray

GSI Gesellschaft für Schwerionenforschung

IEEE Institute of Electrical and Electronics Engineers ISS International Space Station

LEO Low-Earth Orbits

LET Linear Energy Transfer LHC Large Hadron Collider MPU Multiple-Cell Upsets

NA North Area

NIEL Non Ionizing Energy Loss

PCB Printed circuit boards

PIF PSI’s Proton Irradiation Facility

PS Proton Synchrotron

PSI Paul Scherrer Institute

PTW Physikalisch-Techn. Werkstätten Dr. Pychlau GmbH

QA Quality Assurance

RADEF RADiation Effects Facility

RADSAGA RADiation and reliability challenges for electronics used in Space, Avionics, on the Ground and at Accelerators

RITRACKS relativistic ion tracks RNG random number generator RPP rectangle parallelepiped

SEB Single Event Burnouts

SEDR Single Event Dielectric Ruptures SEE Single Event Effect

SEFI Single Event Functional Interrupt SEGR Single Event Gate Ruptures SEHE Single Event Hard Error SEL Single Event Latchups

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SET Single Event Transients

SEU Single Event Upset

SPE solar proton events SPS Super Proton Synchrotron SRAM Static Random-Access Memory SRIM Stopping and Range of Ions in Matter

SV sensitive volume

TAMU Texas A&M University

THz Terahertz

TID Total Ionizing Dose

UCL Université Catholique de Louvain UHE ultra-high energy

VESPER Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments

VHE Very High Energy

VHEE Very High Energy Electron

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Chapter 1: Introduction

Modern state of the art technology is implemented in cars, airplanes, or in medical devices.

These electronic components are continuously and very quickly becoming more advanced and complicated. However, this fast development brings not only better performance and higher quality. It might also cause an increased sensitivity to radiation [3, 4]. Due to lowering the circuit size, capacitance, and resulting lower supply voltage needs, modern circuits are more prone to errors. This is caused by charge disturbing the device and leading to a soft error by flipping a logic level. The minimum level of charge inducing this process is called critical charge (Qcrit) and defines the sensitivity of a device [5].

Devices used in terrestrial applications are mostly protected from charged particles by the magnetic field and the atmosphere of the Earth. Neutrons and muons stemming from galactic cosmic radiation represent an exception from this. Additionally, there are man made radiation sources such as radiation facilities for electronic testing and research purposes. Electronic components installed within such facilities have to handle enormous radiation exposure, depending on the beam parameters and surrounding materials [6, 7]. The aerospace industry is another area where radiation may pose a risk to the reliability of airplanes [8]. Although not as harsh as in space or in accelerator environments, the radiation levels at flight altitudes are significantly higher than at the surface of the Earth. Lastly, looking at manned space missions, the crew is totally dependent on the functionality of the equipment. Both the people and the electronics on the spacecraft are not protected anymore by the Earth’s magnetic field and atmosphere. Hence, they are fully exposed to the radiation environment in space [9].

Therefore, the response of electronics components in different radiation environments need to be investigated and understood to ensure their functionality. For this reason, this work has been devoted to addressing some of the questions that contribute to improve the knowledge and understanding in this field. It has led to some fundamental insights of the physical processes within material while exposed to a particle and energy composition comparable to the galactic cosmic radiation (GCR) environment: from energy deposition mechanisms to nuclear fragmentation processes and general behaviour of ultra-high energy (UHE) beams. UHE heavy ion beams at CERN (Switzerland) have been used for the experiments presented in this PhD thesis. This is relevant, because the current standard way of testing electronic components for space applications uses heavy ion beams of a Linear Energy Transfer (LET) similar to the LET of the heavy ions present in space [10]. For these tests, the accelerator should be able to provide ions with a range of at least 40 µm in silicon with variable flux ranging from a few 10 ions/cm²/s to at least 10⁵ ions/cm²/s on the device under test [9]. This approach assumes that similar LET values, independent of the particle energy, will induce the same effects in electronic components. This is due to the facts, that the LET is used in general to describe the energy deposited by a particle while travelling through material.

Within a device, the single event effects response to radiation is defined by its sensitivity and can be described by the concept of its cross-section. Following the hypothesis made above, the cross-section should be nearly identical for ions of same LET, independent of the ion type or energy. This seems to be the case for a LET above approximately 5 MeV cm²/mg, as can be seen in Fig. 1, where the cross-section of a Single Event Upset (SEU) sensitive device is given as a function of LET for different ions and ion energies [11]. However, for the lower sub-LET region, this concept does not apply. Here the beams of different energies result in different cross-sections despite having the same LET. The sub-LET region represents the area below a

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threshold in which the energy deposition takes place through indirect rather than direct ionization.

Fig. 1. Cross-section of the SEU monitor versus heavy ion LET at the facilities RADiation Effects Facility (RADEF) with 9.3 MeV/u, Texas A&M University (TAMU) with 25 MeV/u, Gesellschaft für

Schwerionenforschung (GSI) with 100 to 1000 MeV/u. For RADEF and TAMU, the full and open symbols correspond to normal incidence and tilted angles (45 and 60 degrees). The results around

1.8 MeVcm²/mg are emphasized using a rectangle. Picture taken from [11].

By using UHE beams it is possible to perform beam tests of many components or test setups installed in the beam line at the same time. This can be done, due to the high penetration depth, without suffering a significant energy loss of UHE heavy ion beams. Hence these beams provide a constant Linear Energy Transfer (LET) over large penetration depths, albeit with a loss of beam intensity due to fragmentation. Also, this beam characteristic might enable testing under relaxed test conditions (no vacuum or component opening needed), but it might lead to other difficulties. Due to its novelty, the possible resulting effects in matter are not well investigated at the moment. Leading to the question, is the way of testing with particles of the same LET, but different energy compared to the space environment, representative enough?

To answer this, three of my publications have focused on this aspect through simulations concentrated on the energy deposition mechanisms of UHE heavy ion beams in matter.

Paper 1 has been dedicated to the differences between standard space application test energies and particles in direct comparison to UHE heavy ions. Then, Paper 2 and 3 have targeted the energy deposition and behaviour of an UHE lead beam in more detail.

Specifically, Paper 2 focused on LET investigations and energy deposition within a silicon diode, and was followed by Paper 3, where a well-established medical physics detector array and Gafchromic films have been used to study the beam dosimetry of an UHE lead beam. Both studies have shown that the physical phenomena occurring in these beams are not trivial and deserve further investigations. Also, the importance of an accurate beam dosimetry and knowledge about beam parameters have been proven to be critical.

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The GCR environment dominates the space radiation environment in deep space. Additionally, to this radiation source, there are trapped radiation fields created by the magnetic fields of planets. As the magnetic field of our Earth protects us from incoming particles, every planet with such a magnetic field is influencing the radiation around itself. One of them is Jupiter.

Since there are space missions, which are crossing the radiation fields surrounding Jupiter, the electronics on the spacecraft need to be designed to survive this exposure.

Some questions might arise from this knowledge. How can high-energy electron beams such as those available at CERN be used to test electronics for future space missions, which will be exposed to electron-rich environments as around Jupiter? Are there non-linear effects related to high instantaneous intensities of electron fluxes by changing the amount of charge per pulse?

Related to these questions, Paper 4 presents results from experiments performed in the Very High Energy Electron (VHEE) beam at the CERN Linear Electron Accelerator for Research (CLEAR) facility. These experiments have served to investigate possible non-linear effects while testing in an electron-rich radiation environment with high energies. Such energies are comparable to existing radiation environments, such as can be found around Jupiter [12]. Earlier studies have shown that the response of devices might show a non-linear effect when exposed to high energy electrons. This threshold is relevant to know and might impact how the testing should be performed [1].

This dissertation is built in the way that the reader can see the connection points of the individual publications and the overall outcome. Starting with a theory background in chapter 2, followed by chapter 3 describing the simulations and experiments necessary to understand and perform the work presented in the published Papers. In chapter 4 a summary of the four included Papers can be found. Moreover, chapter 5 presents a discussion of the achieved results and chapter 6 the resulting conclusion. At the end of this thesis, the included Papers can be found in their published form. Paper 4 is included as the accepted conference Paper.

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Chapter 2: Theoretical Background

2.1 Introduction

To estimate the Single Event Effect (SEE) cross-section and response of the electronic components in space, it is crucial to understand the effect of the relevant radiation environment on the installed components. For this reason, radiation facilities offer a variety of particle species and energies all over the world. Radiation facilities related to this work are introduced in this chapter. These facilities provide the possibility for SEE testing and SEE cross-section estimation of a certain Device Under Test (DUT). This is a meaningful parameter and often decides whether a component will be used on a space mission.

This work is dedicated to the investigations related to radiation environments present in space and in special accelerator types available at CERN. Hence, this chapter gives an overview of the relevant radiation environments as well as the involved physical processes and effects in electronics.

Furthermore, a good understanding and control of the beam during the experiments is of high importance. Therefore, beam dosimetry methods have been applied for the performed measurements of this work. Basic knowledge about this can also be found in this chapter.

2.2 Radiation environment in space

The radiation environment in space or more specifically within the solar system is a mixture of many different particle species and energies. Various high-energy charged particles such as protons up to heavy ions like iron (or heavier), photons, electrons, neutrons and other reaction products can be found in space [13]. These particles either originate from solar energetic particles, trapped inside the magnetic field of a planet or enter the heliosphere from outside as galactic cosmic rays with energies up to several GeV/n [14]. The following sections will describe these sources since they are relevant for the studies presented in this work. However, this PhD is mainly focused on the GCR environment.

An overview of the radiation present in space and the effect it has on electronic devices can be seen in Fig. 2.

Fig. 2. Correlation between radiation sources in space and the effects on electronic components.

Picture taken from [15].

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2.2.1 Solar particles and Earth’s magnetosphere

Charged particles are continuously emitted by the Sun as solar wind. Due to the low energy, even at times of high solar activity, the solar wind does not represent a serious issue for radiation protection of humans or electronics on board of a spacecraft. The emitted particles can easily be shielded by a thin protection layer [14]. In addition to the steady solar wind, the sun has events, where many energetic particles are emitted. This occurs during a solar eruption and ejects mainly protons and electrons, but also a small amount of helium and heavy ions can be present as well. These phenomena are called solar particle events or solar proton events (SPE) and when an extreme high amount of material is ejected into space, this event is classified as a coronal-mass ejection [14].

All these particles can be trapped by the interplanetary magnetic field of a planet. This leads to a radiation field surrounding the planet like a dipole magnet. As a consequence, this planetary magnet field interacts with the solar wind in a way that creates a cavity filled with low-density hot plasma of particles originating from the solar wind or the planet itself [17].

These trapped particles are called radiation belts and represent a serious source of radiation damage for space missions and applications crossing them. The belts of the Earth are called

“Van-Allen belts”. The electrons in the outer belt reach up to 7 MeV and the protons of the inner belt up to 600 MeV, the few heavy ions there have energies below 50 MeV/n [14]. Due to their low-energy the heavy ions trapped in the belt are assumed to have a small penetration depth and therefore are no risk factor for space applications [14]. Some of the protons in the inner belt have an energy of 10-100 MeV and are stemming from Cosmic Ray Albedo Neutron Decay (CRAND) [16]. Especially the inner proton belt, is of high importance for missions operating in the region of the Low-Earth Orbits (LEO), such as on the International Space Station (ISS) or Earth-observation in general [14]. An illustration of the Van-Allen belts can be found in Fig. 3 [13].

Fig. 3. Van-Allen radiation belts of the Earth and the fluence rates of the protons and electrons in cm-2 s-1 taken from [13].

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Other planets like Jupiter, Saturn, Uranus, and Neptune are also inducing a strong magnetic field around them and hence are surrounded by radiation belts. Mercury has only a weak magnetosphere and therefore only transient radiation belts [10].

2.2.2 Jovian magnetosphere

As described in the subsection before, the magnetosphere of the Earth is mainly solar wind driven. This means that the energy and plasma stems from caught solar particles. Different to this is the magnetic field around Jupiter. The Jovian magnetosphere derives its energy from Jupiter’s fast rotation and equatorial dynamo, which creates a very strong magnetic field of an intensity of approximately 4 Gauss [17]. Together with the fast rotation (rotation period ~9 h 55 min) the generated Jovian magnetosphere is very strong and has a large size. It derives most of its plasma from one of its satellites, Jupiter’s moon Io [17]. Jupiter’s magnetosphere is divided into different regions and is in its mechanisms very complex.

For this work the Jovian radiation environment is of interest, due to the different space missions crossing Jupiter and future ones [18, 19]. On these missions, electronics are installed and need to be radiation robust against the specific exposure around Jupiter. High energy electrons up to 100 MeV are present in the Jovian magnetosphere [12].

This work has therefore explored the use of high-energy electron beams at CERN for testing of electronics in a comparable energy range [20].

2.2.3 Galactic cosmic rays

On the Earth the galactic cosmic radiation shows an isotropic distribution due to the particle origin located outside of the solar system. The processes involved in the creation of these rays are unknown. So is the source direction, because the particles are deflected through irregular interstellar magnetic fields before they reach the Earth. This radiation type can reach up to 10²⁰ eV and stems therefore most likely from physical events where very high energies are involved such as supernovae, neutron stars or pulsars [14].

In terms of composition, the GCRs can be characterised as 98% baryons, of which 85% are protons, 14% alpha particles and 1% heavy ions (Fig. 4). The remaining 2% are electrons [14].

Looking at the low percentage of heavy ions and hence their impact on space missions, this appears to be not significant.

Fig. 4. Illustration of particle composition in space. Data taken from [14].

98%

2%

GCR PARTICLE COMPOSITION

Baryons Electrons

85%

14% 1%

98% BARYONS CONSIST OF:

Protons Alpha Particles Heavy Ions

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However, these ions are highly energetic and their contribution to the GCR dose is relevant due to the squared relation between the absorbed dose and the incident particle charge (Z) [2].

Another part of the GCR environment is called the anomalous component. During the process of entering the heliosphere, these once neutral particles coming from interstellar gas have been singly ionized by the solar radiation. This radiation type shows energies around 20 MeV/n and is only able to induce radiation effects if the shielding is thin [2].

Cosmic radiation is modulated through the 11-year cycle of the Sun in a way, that when the solar activity is high, the GCR flux is low and vice versa during low solar activity. The pressure changes produced by the solar wind, which is a continuous stream of high ionized plasma emitted from the Sun, pushes incoming particles away from the solar system during maximum solar activity. Hence, during a maximum of the Sun cycle, the GCR flux within the solar system is at its minimum. This behaviour can be seen in Fig. 5, where the spectral radiance is given for hydrogen, helium, oxygen, and iron over their particle energy and related to the solar cycle maximum and minimum [5].

Fig. 5. The energy spectrum of hydrogen, helium, oxygen, and iron of the GCR environment during a minimum and maximum of a solar cycle. Picture from [14].

2.3 Single Event Effects test facilities

To perform standard SEE radiation tests for future space applications it is necessary to reproduce the radiation environment in space as closely as possible. Due to this, radiation facilities offer a broad variety of particle types and energies. For space applications, which are exposed to a variety of radiation types, the tests are usually carried out using low energy heavy ion (around 10 MeV/n). This approach relies on the assumption that the occurring effects are similar to the heavy ions in space due to an identical LET. However, in space, ions with higher energies are present as well. Whether testing at low energies is the most appropriate way should

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therefore be discussed. Also, high energy protons are present in large quantities in space and have therefore a serious impact on exposed electronics. For this reason, testing with high energy protons is also highly relevant.

The following sections focus on the test facilities relevant for this PhD thesis. An overview of the test facilities in Europe and the standards can be seen in [15]. Of course, there are more facilities all over the world, where one can test electronics with different beams.

2.3.1 High energy protons

The Paul Scherrer Institute (PSI) in Switzerland and more specifically the PSI’s Proton Irradiation Facility (PIF) are part of the European Space Agency (ESA) and CERN standard test facilities for electronic components. The PSI institute itself hosts a broad variety of research projects in the field of engineering and natural science. Additionally, it also consists of different test facilities of which the PIF is accelerating protons in air currently up to approximately 230 MeV [21]. This energy can be degraded by copper plates with different thicknesses according to the desired resulting proton energy and is delivered to the experimental area of the PIF facility [22, 23]. This proton beam is designed to reproduce any proton spectra present at orbits used for space missions and therefore represents an excellent opportunity to perform ground level testing for the space community [21].

Another facility, the RADiation Effects Facility (RADEF) is part of the accelerator laboratory of the department of physics in Jyväskylä (Finland). This facility is also one of the ESA standard test facilities and offers dedicated beam lines especially for SEE testing. There provided protons can range from 0.5 MeV to 55 MeV. High energy protons can be delivered in air and low energy protons in vacuum [24].

As mentioned above, high energy protons represent a major part of the radiation environment in space. Therefore, they are part of every radiation test procedure for new spacecraft electronics. To compare the differences and similarities in the fragmentation processes with UHE heavy ions, experimental high proton data as well as Monte Carlo simulations focusing on fragmentation and energy deposition are included in Paper 1.

2.3.2 Low energy/standard energy heavy ions (<10 MeV/n)

The importance of low energy heavy ions (~10 MeV/n) in the context of this work is why in Paper 1 experimental data of low energy, also referred to as standard energy heavy ions, have been included. Furthermore, Monte Carlo simulations have been performed and presented in Paper 1 to investigate the effects occurring in these beams on a nuclear interaction.

One of the available facilities offering a test possibility with low energy heavy ions is RADEF.

This beamline can provide a heavy ion cocktail up to 22 MeV/u in air or vacuum. Within this cocktail, the heavy ion species can be chosen. Consisting of different ion species with the same mass to charge ratio, this so-called cocktail allows a fast change in delivered ion species by swapping between them [24].

Another facility in Europe to test with low energy heavy ions is the Université Catholique de Louvain (UCL) in Belgium. UCL, like RADEF, provides the ions by using a heavy ion cocktail in which different ions can be chosen. Moreover, the beam flux can be modified, depending on the user’s needs [25].

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2.3.3 Ultra-high energy heavy ions (5-150 GeV/n)

The radiation fields present in modern particle accelerators are comparable to the one in space in manifold aspects, especially at high-energy particle accelerators such as available at CERN via the Large Hadron Collider (LHC). The exposure to radiation is responsible for most of the failures experienced by electronics installed within the beam lines. More specifically, the continuous exposure to mixed particle and energy radiation fields lead to radiation damage.

This has a significant impact on the lifetime of an electronic component. However, the components need to be as radiation hard as possible. Furthermore, since some of these instruments have the purpose of performing dosimetric tasks, the loss of efficiency needs to be counted in when the results given by these instruments are analysed. In other words, the physical effects of particles present in these beam lines need to be understood and known.

At CERN, other facilities are supplied by the LHC with UHE particles. Usually these particles are protons, but during the heavy ion runs 2017 and 2018, UHE xenon and UHE lead have been available. Like this experiments could be performed in the North Area and at the CERN High- energy AcceleratoR Mixed field (CHARM). Using this beam from the LHC, CHARM can provide a mixed field radiation environment [26]. In addition to this mixed field and indirect UHE proton testing, a direct beam can also be achieved at CHARM [27].

The beam provided by the LHC is also used by fixed-target experiments, installed directly within the LHC. In this manner, these experiments have been able to use the accelerated heavy ions directly on the spot [28].

For this work, the experiments included in Paper 1, 2 and 3 have been performed in the Super Proton Synchrotron (SPS) North Area and CHARM in 2017 and 2018. Again, Monte Carlo simulations have been performed and compared to the experimental results in all three Papers.

2.3.4 High-energy electrons at CERN

UHE heavy ions and protons are not the only particles available at CERN, very high-energy electrons can also be delivered at the CERN Linear Electron Accelerator for Research (CLEAR). This linear accelerator beamline is based on two klystrons and can provide electrons in the energy range between 55 and 220 MeV. There, radiation tests on electronic components can be carried out at two test stations: The Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments (VESPER) and Terahertz (THz). Both test areas are located in the same irradiation hall. The electrons can be generated via dark current of the electron gun, if a low electron flux is requested or through laser excitation to achieve very high electron fluxes [29, 30].

2.4 Interaction with matter

As soon as a particle interacts with matter, it will lose some of its initial energy. This can happen either through direct ionization processes or nuclear interactions. Furthermore, projectile excitation and ionization, electron capture, recoil loss, electromagnetic radiation or chemical processes can lead to an energy loss of the travelling particle. The energy loss of the incident particle during the process of traversing through a material per unit distance is defined and referred to as the stopping power [31].

2.4.1 Linear energy transfer

The LET or mass stopping force defines the energy deposited by an incoming particle within the penetrated material. This might seem similar and it is for many, but not for all cases. If a

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particle is energetic enough and reacts with the atoms of the material it is travelling through by creating delta electrons, which are electrons of very high energy escaping the target volume, this energy is lost by the primary particle yet to be deposited in the matter. This would be one case, where the stopping power and the LET are not the same.

In general, the LET can be described by:

𝐿𝐸𝑇 = −1 𝜌

𝑑𝐸 𝑑𝑥

where dE is the deposited energy by an incident particle, dx represents its travelled distance within the penetrated material and 𝜌 is the material density [32]. The LET serves as a measure to describe heavy ion induced SEEs in electronics [4]. In the ultra-high energy regime, the energy loss and hence the LET is minimal and is considered to be constant for a particle travelling through matter.

2.4.1.1 Effective LET

The effective energy deposited by an ion in a layer of material depends on the incident angle between the incoming particle and the target. Hence, the effective LET can be written as:

𝐿𝐸𝑇_𝑒𝑓𝑓 = 𝐿𝐸𝑇₀ 𝑐𝑜𝑠 (𝜃)

LET0 is the LET of an incoming particle orthogonal to the target surface, whereas 𝜃 describes an angle of incidence as can be seen in Fig. 6 where the red arrow marks the impinging particle, the green area is the angle of incidence in relation to the normal angle and the blue square represents the target volume.

Fig. 6. Effective LET illustration.

The concept of effective LET is not universally applicable. For target volumes where the lateral dimensions are not significantly larger than its thickness, the idea of the effective LET cannot be applied. This is due to the ion trajectory within the target material, which does not obey the

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1

𝑐𝑜𝑠 law anymore if the lateral size is comparably small to the thickness. This is often the case in modern technology, where the lateral dimensions are commonly smaller than the sensitive volume thickness, or if an ion range is shorter than the material it is travelling through. In this case, the particle deposits a significant amount, if not all, of its energy within the target [4].

Hence, the LET needs to be calculated in relation to the given test parameters.

2.4.1.2 Volume equivalent LET

Since modern technology geometries are getting smaller and the effective LET concept becomes less relevant, the concept of volume equivalent LET can be used instead to calculate the LET of a particle travelling through matter. However, only if the ion does not lose a significant amount of energy during its passage through the target volume. This can be the case, for very energetic incident particles, or if the target thickness is small enough. However, for standard ground level testing (around 10 MeV/n), the volume equivalent LET is typically similar to the unrestricted LET value, which represents the inclusion of all emitted delta electrons regardless of their range [13], as shown by Alía et al. in [33]. This is illustrated in Fig.

7, where a discrepancy between the unrestricted (plotted as lines) and the volume equivalent LET (shown as crosses) can be seen for energies above 1 GeV/n for xenon (green), lead (blue) and uranium (red). Marked in grey is a LET value above 15 MeV·cm2/mg, which is high enough to exclude SEEs in silicon induced by heavy ions in a high-energy accelerator mixed- field. This is relevant, since the volume equivalent LET is the used measure for electronics testing and is clearly below the unrestricted value for higher energies, where the unrestricted LET reaches the threshold value of 15 MeV·cm2/mg for lead and uranium [33].

Fig. 7. Unrestricted (lines) and volume equivalent LET (crosses). The solid lines are calculated by Stopping and Range of Ions in Matter (SRIM), the dashed lines via FLUKA. Picture taken from [33].

The volume equivalent LET can be determined by integrating the energy deposited, 𝐸_𝑑𝑒𝑝, in the whole target volume and dividing it by the volume thickness and density 𝜌:

𝐿𝐸𝑇𝑣𝑜𝑙𝑢𝑚𝑒 𝑒𝑞𝑢. = ∬ 𝐸_𝑑𝑒𝑝𝑑𝑥𝑑𝑦 𝑣𝑜𝑙𝑢𝑚𝑒 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 ∙ 𝜌

Another way to calculate this LET value can be done by determining the direct ionization peak in a deposited energy distribution as shown in [34]. Such an energy distribution can either be

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simulated or experimentally obtained (as it is the case in Fig. 8). In Fig. 8, the counts per spill are shown as a function of the particle energy in MeV for a 150 GeV/n lead beam in 140 µm silicon.

Fig. 8. Experimentally retrieved deposited energy distribution of 150 GeV/n lead in a 140 µm silicon detector during the test campaign 2018 in the North Area (NA) at CERN. Picture taken from Paper

2.

The peak occurs at 255 MeV deposited energy [34], by applying the formula above, a volume equivalent LET of 7.85 MeV/𝑚𝑔 ∙ 𝑐𝑚² can be calculated as follows:

𝐿𝐸𝑇𝑣𝑜𝑙𝑢𝑚𝑒 𝑒𝑞𝑢. = 255 [𝑀𝑒𝑉]

0.014 [𝑐𝑚] ∙ 2.32 ∙ 10³[𝑚𝑔

𝑐𝑚³] = 7.85 [ 𝑀𝑒𝑉 𝑚𝑔 ∙ 𝑐𝑚²]

2.4.2 Direct ionization and energy deposition

Direct ionization describes an occurring physical process, when an energetic particle penetrates material and deposits its energy through electromagnetic interactions. Along the trajectory of the projectile, electron-hole pairs are created. This means that the incident particle interacts with the valence electrons of the target atoms.

These interactions between the electromagnetic field of the incident particle and the electrons surrounding the target volume atoms lead to an energy loss of the projectile, which slows it down as a result. The slower the primary particle becomes, the more increases its energy loss per unit length or LET and can be described by the Bethe-Bloch formula [35]:

𝑑𝐸

𝑑𝑥 = −𝑘𝜌 (𝑍 𝐴)

𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙

(𝑍 𝐴)

𝑝𝑟𝑜𝑗𝑒𝑐𝑡𝑖𝑙𝑒 2

[𝑙𝑜𝑔 𝑙𝑜𝑔 ( 2𝑚_𝑒𝛽²

𝐼(1 − 𝛽²)) − 𝛽²]

Here, dx represents the distance a particle travels through matter, dE is the energy loss over the distance dx, A is the mass number of the incident ion, Z its atomic number, k is a constant, β

0 50 100 150 200 250 300

Energy [MeV]

10^-2 10^-1 10⁰ 10¹

counts/spill

experimental data

Unique particle beams and energies at CERN applied to radiation testing of