Safety aspects for the design and operation of new accelerator facilities 1
a) During the acceleration cycle in the synchrotron, a small fraction of the partially stripped ions will loose electrons due to interaction with the rest gas. These ions leave the orbit and hit the beam tubes, thus inducing radiation. The vacuum specifications for SIS100/200 are such that these beam losses are tolerable. The radiation has also to be kept to a low level in order to avoid the quenching of the superconducting magnets. Nevertheless, the required shielding is quite substantial what made the choice of an underground installation for the SIS100/200, also motivated by ecological considerations, rather obvious.
RADIATION PROBLEMS IN THE DESIGN OF THE LARGE ELECTRON - POSITRON COLLIDER (LEP)
This is a comprehensive review of the radiation problems taken into account in the design studies for the Large Electron-Positron collider (LEP) now under construction at CERN. It provides estimates and calculations of the magnitude of the most important hazards, including those from non-ionizing radiations and magnetic fields as well as from ionizing radiation, and describes the measures to be taken in the design, construction, and operation to limit them. Damage to components is considered as well as the risk to people. More general explanations are given of the physical processes and technical parameters that influence the production and effects of radiation, and a comprehensive bibliography provides access to the basic theories and other discussions of the subject. The report effectively summarizes the findings of the Working Group on LEP radiation problems and parallels the results of analogous studies made for the previous large accelerator. The concluding chapters describe the LEP radiation protection system, which is foreseen to reduce doses far below the legal limits for all those working with the machine or living nearby, and summarize the environmental impact. Costs are also briefly considered.
A comparison of the radiation damage of electronic components irradiated in different radiation fields
Abstract Resistors, capacitors, silicon diodes and transistors, TTL integrated circuits, and operational amplifiers have been irradiated in three different radiation environments: in a research reactor with up to 1015 n/cm2 (E>1 MeV), near a proton beam of the CERN Intersecting Storage Rings with up to 5 × 105 Rad, and with a 30 kCi 60Co gamma source with up to 1 × 107 Rad. Representative parameters, such as resistance, capacitance, forward voltage, reverse current, toggle frequencies, have been measured before and after irradiation. It was found that, in comparison with nuclear-reactor irradiations, the effect of 60Co gamma rays can be smaller by a factor of 100 or more, whereas high-dose-rate accelerator irradiation can be up to 5 times more damaging for the same nominal amount of irradiation. It is concluded that care has to be exercised when interpreting the results of radiation damage tests on electronic components in different radiation environments.