Draft: Rules concerning Superconducting Magnets and Dilution Refrigerator Experiments

Experiments involving superconducting magnets and/or dilution refrigerators are labor-intensive for the sample environment staff and imply a quite high risk of problems, especially at the beginning of an experiment. We therefore suggest to implement rules for this type of experiments.

Restrictions concerning magnets and/or dilution refrigerator experiments

• On weekends or holidays, is not possible to start magnet or dilution refrigerator experiments
• Support during weekend or in the evening may not be provided (there is no sample environment stand-by). If problems occur, it should be tried to contact the sample environment staff, but not during the night (10 p.m. - 8 a.m.). In the case that the contact can not be established, the experiment might have to be suspended until the next working day.
• Aligning the sample with neutrons must be done before the starting day.

Restrictions concerning dilution refrigerator experiments

• On weekends or holidays, sample changes are not possible
• Experiments starting on Fridays (or at a day before a holiday) are only allowed at the beginning of a beam block, i.e. when the refrigerator can already be mounted on the instrument the day before.
• The sample must be ready a workday before starting the experiment, except for the case where the stick is already used immediately before. In this case the rules for sample changes apply.
• Sample changes take a full working day, i.e. the warming up of the old sample must start before 8 a.m. Be aware that a delay of a working day may occur after a sample change.

Dilution Scheduling Policy

Since we have 2 dilution sticks, the number of experiments with this type of equipment has raised severely. We suggest to implement a limit for dilution experiments: The total number of dilution days plus 3 times the number of experiments should not exceed 120 % of the available SINQ beam days.

The following table shows the situation for the last and for the next cycle. With such a high number of experiments, it is unavoidable to have periods, where 2 dilution refrigerators run at the same time. This is an highly undesirable situation.

As the schedule for the next period is already done, we try to handle the large number of experiments as well as possible. But for the next cycle (Sept-Dec 2007) we want to agree about a scheduling policy. This should ideally be done before the proposal deadline in May.