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Delivery of Beams with the FEBIAD Ion Source
With the addition of the FEBIAD to the pool of available ion sources, ISAC Operations needs to be especially careful as to which species are transported upstairs to the experimental areas.
TRI-ION-07-nn
Date: Dec 20, 2007
Written by Mike Trinczek
Background Information:
For the last several years, ISAC has been operating primarily with ion sources (e.g. surface, RILIS) which are limited in which elements they are capable of ionizing. With the addition of the FEBIAD ion source, the range of species which can be ionized, and hence transported to the experimental areas, increases dramatically. This may have a significant impact on the tuning and delivery of both stable and radioactive ion beams to ISAC experiments.
As an example, tuning in the low-mass range is typically done with stable 7Li. With the FEBIAD, tuning at A/q = 7 could also bring up long-lived (t½ = 53 days) 7Be. In addition, the FEBIAD can ionize molecules and produce a variety of species in multiple-charge states. At A/q = 8, it is possible to simultaneously extract 8Li, 8He, and 16O2+, making tuning more difficult. At higher mass settings, the possible combinations become more numerous.
Implementation:
As with all target/ion source combinations, ISAC Operations needs to pay very close attention to the Forbidden Species list on the Beam Properties Request (BPR) form submitted for each experiment. Safe use of an isotope or mass setting in the past is not sufficient reason to assume it is safe to use with future target/ion source combinations.
Once a tune has been established by the Beam Delivery group, ISAC Operations will be informed of any precautions necessary to ensure the safe delivery of beam with that target/ion source combination. Using their discretion and judgment, operators should not hesitate to contact the Beam Delivery group for assistance.
For example, if it is unclear at any time exactly which species is being tuned, the Beam Delivery group should be contacted either for confirmation or to bring the beam to the Yield Station for identification. Once the beam in question has been identified with certainty, it can then be sent to the experimental area. If an isotope is requested (say, by an experimenter), that is not explicitly approved on the BPR or Safety Approval forms, an expert from the Beam Delivery group must be consulted. In this manner, ISAC Operations can ensure the safe tuning and delivery of ion beams to experiments.
