Markus Brugger

FLUKA Simulations for SEE Studies of Critical LHC Underground Areas

FLUKA Monte Carlo simulations have been performed to identify particle energy spectra and fluences relevant for evaluating the risk of single event effects in electronics installed in critical LHC underground areas. Since these simulations are associated with significant uncertainties, the results will compared with an online monitoring system installed to evaluate radiation levels at the location of the electronics. This comparison approach have been benchmarked in a mixed field reference facility and for a preliminary LHC monitoring case study.

LHC RadMon SRAM Detectors Used at Different Voltages to Determine the Thermal Neutron to High Energy Hadron Fluence Ratio

The thermal neutron SEU cross-section of the Toshiba SRAM memory used in the LHC RadMon system was measured at different voltages. A method using the difference in its response compared to mixed particle energy field is proposed to be used as a discriminator between thermal neutron and high-energy hadron fluences. For test purposes, the proposed method was used at the CNGS and CERF facilities to estimate the field composition by counting SEUs at two different voltages and the results were compared to simulations.

SEU Measurements and Simulations in a Mixed Field Environment

Single Event Upset (SEU) measurements were performed using the European Space Agencys (ESA) Standard SEU Monitor in the H4 Irradiation mixed-field test area at CERN. The results, tightly correlated with the radiation environment, are compared with those obtained with the CERN Radiation Monitors (RadMons) as well as with the Monte Carlo simulation of the experimental setup using the FLUKA Monte Carlo transport code. In addition, the SEU cross section of the device for particles and energies not available in standard testing (such as charged pions or GeV-energy hadrons) are simulated and discussed, showing an increase of over a factor 2 for nucleons in the 200 MeV-3 GeV range. A monoenergetic SEU cross section measurement at 120 GeV is included in the analysis.

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.

The LHC Radiation Monitoring System - RadMon

Julien Mekki, Sergio Batuca, Markus Brugger, Marco Calviani, Alfredo Ferrari, Daniel Kramer, Roberto Losito, Alessandro Masi, Anna Nyul, Paul Peronnard, Christian Pignard, Ketil Roeed, Thijs Wijnands CERN CERN CH-1211, Geneve 23, Switzerland E-mail:; Julien.Mekki@cern.ch; Sergio.batuca@cern.ch; Markus.Brugger@cern.ch; Marco.Calviani@cern.ch, Alfredo.Ferrari@cern.ch; Daniel.kramer@cern.ch; Roberto.Losito@cern.ch; Alessandro.Masi@cern.ch; Ana.Nyul@cern.ch; Paul.Peronnard@cern.ch; Christian.Pignard@cern.ch; Ketil.Roeed@cern.ch; Thijs.Wijnands@cern.ch

Method for measuring mixed field radiation levels relevant for SEEs at the LHC

At the LHC installed electronics will be exposed to a radiation field of mixed particles over a wide range of energies. While Monte Carlo transport codes can be used for calculations and predictions of radiation levels, the complex operation and layout of the LHC accelerator give rise to significant uncertainties. Dedicated radiation monitors are therefore installed in locations of the electronics to provide an on line measurement of the radiation levels. This paper addresses the method that has been applied to calibrate these radiation monitors for their use in mixed radiation fields. New irradiation tests to determine the sensitivity to neutrons from a few MeV to 20 MeV will be presented along with additional irradiation tests with high energy protons.

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.

Prospects of high energy density physics research using the CERN super proton synchrotron (SPS)

The Super Proton Synchrotron (SPS) will serve as an injector to the Large Hadron Collider (LHC) at CERN as well as it is used to accelerate and extract proton beams for fixed target experiments. In either case, safety of operation is a very important issue that needs to be carefully addressed. This paper presents detailed numerical simulations of the thermodynamic and hydrodynamic response of solid targets made of copper and tungsten that experience impact of a full SPS beam comprized of 288 bunches of 450 GeV/c protons. These simulations have shown that the material will be seriously damaged if such an accident happens. An interesting outcome of this work is that the SPS can be used to carry out dedicated experiments to study High Energy Density (HED) states in matter.

Raman Distributed Temperature Sensing at CERN

A field trial has been performed at the CERN high-energy accelerator-mixed (CHARM) field facility, newly developed for testing devices within accelerator representative radiation environments, to validate the use of Raman-based optical fiber sensors for distributed temperature measurements in highly radiative environments. Experimental results demonstrate that Raman distributed temperature sensors, operating in loop configuration on radiation-tolerant optical fibers, are able to compensate for wavelength-dependent losses and are, therefore, robust to harsh environments, in which a mixed-field radiation, including protons, neutrons, photons, and other particles, is potentially altering the fiber material properties. The temperature profile measured on commercial radiation-tolerant optical fibers shows that a temperature resolution <;1 °C, 0.5-m spatial resolution, is highly reliable and sets the first step toward a distributed measurement system able to monitor the temperature at the CERNs large hadron collider for safety purposes. Such a system will also be helpful in correcting the radiation-induced attenuation temperature dependence in distributed radiation sensing systems based on radiation-sensitive optical fibers.