Comparison between Californian and cyclotron SEU tests

Experimental equipment for performing heavy-ion testing on programmable integrated circuits is presented. The equipment was used along with two different types of heavy-ion simulator to perform SEU (single-event-upset) tests on representative circuits: a dedicated Cf/sup 252/ fission decay source and an 88-in cyclotron. The observed discrepancies between the two results obtained cast doubt on the validity of using californium sources to simulate high-LET (linear-energy-transfer) particles

Preliminary flight data from the Materials Exposure and Degredation Experiment (MEDET)

The Materials Exposure and Degradation Experiment (MEDET) was recently launched to the ISS on Space Shuttle Flight IE, as part of the EuTEF payload on the external payload facility of ESA's Columbus module. The experiment will operate in-orbit for at least 1.5 years, and has the overall objectives of evaluating the effects of the complex low Earth orbit space environment on material properties, investigating material degradation due to contamination, characterising the local ISS environment and measuring the local micro-particle flux. This paper gives a brief overview of the experiment function and the material samples which are being exposed, before presenting some of the early flight data. In this phase of the mission, all of the instruments are operating successfully, and continuously acquiring data. The preliminary results mainly concern the environmental sensors, which are operating at relatively high acquisition rates (e.g. one reading every few seconds). It has been shown that the docking of the Space Shuttle to the ISS has a significant effect on the local pressure environment. The more complex degradation experiments are acquiring at much slower rates (e.g. one reading per day) and several more months of space exposure will be required before sufficient data is generated to reach conclusions about the behaviour of the materials. However, preliminary data is presented. ©2009 American Institute of Physic