Salvatore Danzeca

CHARM: A Mixed Field Facility at CERN for Radiation Tests in Ground, Atmospheric, Space and Accelerator Representative Environments

Depending on the application, electronic systems and devices can be subjected to different radiation environments. According to the type of radiation encountered during operation, electronic components are simultaneously vulnerable to cumulative and single event effects. In addition, inelastic interactions of highly energetic particles with high-Z materials generate highly ionizing products. This can lead to catastrophic failures and therefore can have a significant impact on the reliability of electronic devices. For this reason, it is necessary to test electronic devices/systems in representative environments. For this purpose, a mixed field radiation test facility called CHARM has been established at CERN. Its radiation environment is not only representative of particle accelerators, but also of atmospheric, ground level and space applications.

A New RadMon Version for the LHC and its Injection Lines

A system to monitor the radiation levels is required in the Large Hadron Collider (LHC) and its injection lines in order to quantify the radiation effects on electronics. Thus, the RadMons were installed in critical areas where equipment is or will be placed. The first years of operation, successive test campaigns and new requirements, raised the need for a new design of the monitor. The architecture of the new RadMon, the radiation reliability and the design strategy adopted for the sensors, used for monitoring the mixed radiation field of the LHC accelerator, are described highlighting the achieved improvements in terms of radiation robustness and measurement accuracy of a device which is of interest for many other research institutes.

Mixed Particle Field Influence on RadFET Responses Using Co-60 Calibration

RadFET sensors are used for Total Ionizing Dose (TID) monitoring inside CERN accelerators. While RadFET sensors are typically well characterized with a Co-60 gamma source, their radiation response can be affected when they are used in high-energy mixed particle fields. This paper presents experimental results and corresponding discussions on the effect of CERN accelerator-like environments on the dose measured by 100 nm, 400 nm and 1000 nm thick oxide RadFETs. Simulations of the radiation environment at the CERN test areas have also been performed to investigate the contribution of each particle type to the deposited dose and are used as a tool to understand the observed effects.

SEL Hardness Assurance in a Mixed Radiation Field

This paper explores the relationship between monoenergetic and mixed-field Single Event Latchup (SEL) cross sections, concluding that for components with a very strong energy dependence and highly-energetic environments, test results from monoenergetic or soft mixed-field spectra can significantly underestimate the operational failure rate. We introduce a semi-empirical approach that can be used to evaluate the SEL rate for such environments based on monoenergetic measurements and information or assumptions on the respective sensitive volume and materials surrounding it. We show that the presence of high-Z materials such as tungsten is particularly important in determining the hadron cross section energy dependence for components with relatively large LET thresholds.

Energy Dependence of Tungsten-Dominated SEL Cross Sections

The energy dependence of proton-induced Single Event Latchup (SEL) failures is investigated for different Static Random Access Memories (SRAMs) and an Analog-to-Digital Converter (ADC) through experimental measurements in the 30-230 MeV range. It is observed that for several of them, the measurements are not compatible with a saturation below the maximum energy tested. A Monte Carlo based model is proposed that explains the observed cross section increase through the presence of tungsten near the sensitive region and is used to extrapolate the SEL cross section to larger energies. The significant cross section increases expected by the model up to 3 GeV are quantified and discussed, potentially having a strong impact on the failure rate for energetic environments such as high-energy accelerators or the avionics contexts.

SEE Measurements and Simulations Using Mono-Energetic GeV-Energy Hadron Beams

Single Event Upset (SEU) measurements were performed on the ESA SEU Monitor using mono-energetic GeV-energy hadron beams available in the North Experimental Area at CERN. A 400 GeV proton beam in the H4IRRAD test area and a 120 GeV mixed pion and proton beam at the CERN-EU high Energy Reference Field facility (CERF) were used for this purpose. The resulting cross section values are presented and discussed as well as compared to the several hundred MeV case (typical for standard test facilities) from a physical interaction perspective with the intention of providing a more general understanding of the behavior. Moreover, the implications of the cross section dependence with energy above the several hundred MeV range are analyzed for different environments. In addition, analogous measurements are proposed for Single Event Latchup (SEL), motivated by discussed simulation results. Finally, a brief introduction of the future CHARM (CERN High-energy AcceleratoR Mixed facility) test installation is included.

SEL Cross Section Energy Dependence Impact on the High Energy Accelerator Failure Rate

We use a single event latchup (SEL) model calibrated to heavy ion (HI) and proton data below 230 MeV to extrapolate the proton cross section to larger energies and evaluate the impact of the potential cross section increase with energy on the SEL rate in different environments. We show that in the case of devices with a large LET onset for HI and a certain amount of tungsten near the sensitive volume (SV), the calculated failure rates for energetic environments based on monoenergetic test data can significantly underestimate the real value. In addition, we show through measurements using a 480 MeV beam and an inspection of the devices architecture that the model was successful in estimating the SEL cross section and tungsten volume per cell.

Characterization and Modeling of a Floating Gate Dosimeter with Gamma and Protons at Various Energies

In this work a prototype of a floating gate sensor FGDOS has been characterized with a 60Co source and with protons. The dependency of the sensor sensitivity on the dose rate and accumulated Total Ionizing Dose (TID) are investigated. The proton test permits to measure the sensitivity of the sensor at different incoming particles energies. An analytical model of the sensor is presented in the paper and the theoretical sensitivity for the prototype of FGDOS is evaluated. Finally, the model allows to accurately measuring the charge yield for different particle types and different energies.

Qualification and Characterization of SRAM Memories Used as Radiation Sensors in the LHC

An 8 Mbit 90-nm memory is proposed as a new high energy hadron fluence sensor. The obtained cross sections for protons (30 MeV up to 480 MeV) and thermal neutrons as well as their dependency on the TID together with the control circuitry is presented. Burst events were recorded during irradiation and an analysis on the causes has been performed proposing an algorithm to mitigate and correct the burst multiple events. Finally, the effects of the energy dependency on the measurements in the LHC mixed radiation field are discussed.

A Mixed Field Facility at CERN for Radiation Test: CHARM

A new mixed-field radiation test facility called CHARM is available at CERN since end of 2014. Its radiation environment is not only representative for accelerators, but also for atmospheric, ground level and space applications.