Database on Silicon Nuclei Fragmentation
Complete Nuclear Database Evaluation of Si Fragmentation for Microelectronics
Tech Area / Field
- PHY-ANU/Atomic and Nuclear Physics/Physics
8 Project completed
Senior Project Manager
Zalouzhny A A
Khlopin Radium Institute, Russia, St Petersburg
- IBM Microelectronics, USA, New York\nUniversity of Uppsala / Svedberg Laboratory, Sweden, Uppsala\nUniversity of Uppsala / Department of Neutron Research, Sweden, Uppsala\nUniversity of Lund, Sweden, Lund\nCNRS / IN2P3 / SUBATECH, France, La Chantrerie
Project summaryThe Project focuses on the experimental semi-exclusive study of fragmentation of the 100÷450 MeV/nucleon Si ions in the interactions with the internal targets of hydrogen and deuterium. The experiment is proposed to be carried out at the storage ring of the The Svedberg Laboratory, Uppsala with the final goal of the evaluation of the complete nuclear database on the Si fragmentation reactions induced by the intermediate energy protons and neutrons for microelectronic industries, but which could be also useful for development of transmutation technologies and nuclear medicine as well.
Experimental part of the Project deals with the manufacturing of the multichannel detector of the projectile fragments, the experiment itself, and , finally, the analysis of the experimental data. A hundred channel phoswich detector of the plastic-CsI(Tl) type will be build for the identification of the reaction products within the technological scheme previously developed and tested at the V.G.Khlopin Radium Institute. Complete international cross-comparison of the prescriptions from the exiting theoretical models of the Si fragmentation by the intermediate protons, and by neutrons in particular, will be followed by detailed analysis of the obtained experimental data. Together, this will provide the grounds for the fundamental theoretical understanding of the nuclear processes responsible for the single event upsets of microelectronic devices. Complete nuclear database of the silicon nuclei fragmentation for microelectronic industry will be evaluated as the final result of the Project, which, however, could be used for the development of the transmutation technologies and for nuclear medicine as well.
The current urgency for the nuclear data evaluation on the fragmentation of silicon nuclei induced by the intermediate energy neutrons is justified by sufficient amount of registered events of upsets of microelectronic devices in avionics and public transportation systems even at the sea level. Though there doesn’t exist full understanding of the causes of all observed upsets there are reasons to think that the nuclear fragmentation of the silicon wafer of the device induced by the neutron component of the cosmic rays is the real source of these kind of seldom but potentially dangerous events. Today, microelectronic industry develops new devices with less susceptibility to the near-terrestrial radiation to increase the reliability of the circuits built of new devices. On the other hand, consumers of the devices are interested in reliable predictions for the rates of the upsets of the existing and emerging devices. To satisfy both demands, Monte Carlo simulations are carried out within the realistic geometrical layouts of the devices. Prediction power of such models depends essentially on the quality of the nuclear database on Si fragmentation by intermediate energy neutrons and protons which acts as the input of the used codes. At present time our knowledge of the nuclear reactions induced by the intermediate energy hadrons in Si is far from being full. Emerging systematic errors in simulations of response of devices to the impact of the atmospheric radiation caused by the incompleteness the nuclear data on nuclear reactions in silicon are likely to diminish the efforts of the developers of the new devices. That is why the additional experimental and theoretical study of fragmentation of Si nuclei induced by the intermediate energy neutrons and protons is the urgent problem of today.
Three aspects build up the novelty of our approach to the problem. Firstly, it is the experimental scheme in which reactions are investigated in the inverse kinematics which greatly reduces the costs of the Project. Secondly, it is the usage of the existing internal targets of hydrogen of high luminosity which allow extraction of information on the fragmentation induced by a weakly bounded neutron of the deuteron eventually acting as a “neutron beam”. Finally, it is the usage of unique possibility of operating the storage ring in a slow ramping mode during which the incident energy varies with great accuracy. This opportunity seems to be very attractive since a priori it is not clear which part of the broad energy spectra of the cosmic rays dominates in generation of upsets of the microelectronic devices.
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