The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, dening a circular eld of view of 30 0 diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A lter wheel carrying three kinds of X-ray transparent light blocking lter, a fully closed, and a fully open position, is tted to each EPIC instrument. The CCDs are cooled passively and are under full closed loop thermal control. A radio-active source is tted for internal calibration. Data are processed on-board to save telemetry by removing cosmic ray tracks, and generating X-ray event les; a variety of dierent instrument modes are available to increase the dynamic range of the instrument and to enable fast timing. The instruments were calibrated using laboratory X-ray beams, and synchrotron generated monochromatic X-ray beams before launch; in-orbit calibration makes use of a variety of celestial X-ray targets. The current calibration is better than 10% over the entire energy range of 0.2 to 10 keV. All three instruments survived launch and are performing nominally in orbit. In particular full eld-of-view coverage is available, all electronic modes work, and the energy resolution is close to pre-launch values. Radiation damage is well within pre-launch predictions and does not yet impact on the energy resolution. The scientic results from EPIC amply full pre-launch expectations.

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The European Photon Imaging Camera on XMM-Newton: The MOS cameras

Physical mechanisms responsible for nondestructive single-event effects in digital microelectronics are reviewed, concentrating on silicon MOS devices and integrated circuits. A brief historical overview of single-event effects in space and terrestrial systems is given, and upset mechanisms in dynamic random access memories, static random access memories, and combinational logic are detailed. Techniques for mitigating single-event upset are described, as well as methods for predicting device and circuit single-event response using computer simulations. The impact of technology trends on single-event susceptibility and future areas of concern are explored.

Basic mechanisms and modeling of single-event upset in digital microelectronics

Ground level upsets have been observed in computer systems containing large amounts of random access memory (RAM). Atmospheric neutrons are most likely the major cause of the upsets based on measured data using the Weapons Neutron Research (WNR) neutron beam.

Single event upset at ground level

Radiation-induced single event upsets (SEUs) pose a major challenge for the design of memories and logic circuits in high-performance microprocessors in technologies beyond 90nm. Historically, we have considered power-performance-area trade offs. There is a need to include the soft error rate (SER) as another design parameter. In this paper, we present radiation particle interactions with silicon, charge collection effects, soft errors, and their effect on VLSI circuits. We also discuss the impact of SEUs on system reliability. We describe an accelerated measurement of SERs using a high-intensity neutron beam, the characterization of SERs in sequential logic cells, and technology scaling trends. Finally, some directions for future research are given.

Characterization of soft errors caused by single event upsets in CMOS processes

Trends in terrestrial neutron-induced soft-error in SRAMs from a 250 nm to a 22 nm process are reviewed and predicted using the Monte-Carlo simulator CORIMS, which is validated to have less than 20% variations from experimental soft-error data on 180-130 nm SRAMs in a wide variety of neutron fields like field tests at low and high altitudes and accelerator tests in LANSCE, TSL, and CYRIC. The following results are obtained: 1) Soft-error rates per device in SRAMs will increase x6-7 from 130 nm to 22 nm process; 2) As SRAM is scaled down to a smaller size, soft-error rate is dominated more significantly by low-energy neutrons (<; 10 MeV); and 3) The area affected by one nuclear reaction spreads over 1 M bits and bit multiplicity of multi-cell upset become as high as 100 bits and more.

Impact of Scaling on Neutron-Induced Soft Error in SRAMs From a 250 nm to a 22 nm Design Rule

A 3-D entire SRAM cell, based on a 0.35-/spl mu/m current CMOS technology, is simulated in this work with a DEVICE simulator. The transient current, resulting from a heavy ion strike in the most sensitive region of the cell, is studied as a function of the LET value, the cell layout and the ion penetration depth. A definition of the critical charge is proposed and two new methods are presented to compute this basic amount of charge only using SPICE simulations. Numerical applications are performed with two different generations of submicron CMOS technologies, including the determination of the sensitive thicknesses.

Determination of key parameters for SEU occurrence using 3-D full cell SRAM simulations

This paper investigates an approach to study the effects of upsets on the operation of microprocessor-based digital architectures. The method is based on the injection of bit-flips, randomly in time and location by using the capabilities of typical application boards. Experimental results, obtained on programs running on two different digital boards, built around an 80C51 microcontroller and a 320C50 Digital Signal Processor, illustrate the potentialities of this new strategy.

Predicting error rate for microprocessor-based digital architectures through C.E.U. (Code Emulating Upsets) injection

In this paper, the Multi-Scales Single Event Phenomena Predictive Platform (MUSCA SEP3) is presented. This platform is dedicated to predicting SEE cross sections or rates and evaluated thanks to on-board operational results on memories from the ICARE experiment (SAC-C mission). It allows for investigating the single and multiple events thus, MUSCA SEP3 helps at estimating sensitivity trend for nano-metric technology and more particularly investigating the emerging effect related to the direct proton ionization. It is a critical problematic which concerns both the space and atmospheric environments.

Operational SER Calculations on the SAC-C Orbit Using the Multi-Scales Single Event Phenomena Predictive Platform (MUSCA ${\rm SEP}^{3}$ )

This paper presents an empirical model for proton induced Single Event Upset (SEU). This model is based on heavy ion data, and will improve the previous 'two parameters' Bendel model. Application to various parts is presented.

An empirical model for predicting proton induced upset

Two new CMOS memory cells, called HIT cells, designed to be SEU-immune are presented. Compared to previously reported design hardened solutions, the HIT cells feature better electrical performances and consume less silicon area. SEU tests performed on a prototype chip prove the efficiency of the approach. >

Robert Ecoffet

Papers

Determination of key parameters for SEU occurrence using 3-D full cell SRAM simulations

Predicting error rate for microprocessor-based digital architectures through C.E.U. (Code Emulating Upsets) injection

Operational SER Calculations on the SAC-C Orbit Using the Multi-Scales Single Event Phenomena Predictive Platform (MUSCA ${\rm SEP}^{3}$ )

An empirical model for predicting proton induced upset

Two CMOS memory cells suitable for the design of SEU-tolerant VLSI circuits