MICE Target - Risk Lara Howlett University of Sheffield

Overview A first detailed Risk Assessment has been produced This is necessary from both the MICE perspective and the ISIS perspective  We need to convince ISIS that the risks to ISIS are extremely low in order to get permission to put the target in  Any failure causing damage to ISIS obviously has serious repercussions for MICE This talk will discuss risks identified and further work to be done to understand the level of risk and reduce the level of risk

Risks – Mechanical Breaking of mechanical components  Shaft  Detachment of comb  Magnets  Ceramic Bearings  Ceramic tube  Glass window It is not clear how the likelihood of these risks can be quantified Clearly all components will be tested before being installed, so the outstanding issue will be that of fatigue over time.

Risks - Mechanical Failure of jacking mechanism Failure of indium seals Leak in water cooling Target Melts Failure of gate valve

Risks - Electrical The most significant problem will be excessive heating if an electrical failure causes high currents to be put through the coils for too long Possible problems caused by heating  Damage to coils  Demagnetisation of magnets  Outgassing at high temperatures  Overheating of ceramic causes failure in indium seals It is anticipated that in the long term both hardware and software interlocks to prevent this occurring will be in place. These may not be ready for November.

Risks Electrical Failure of the Hex bridge due to a Mosfet failure is likely to occur at some point (likely timescale should be examined but is expected to be ~ few years)  ISIS will be tripped off and the target will need to be jacked out of the beam  Further operation will not be possible until the Hex bridge is replaced A computational error from electronics causing incorrect target insertion/dropping of target is also possible  Probability needs to be tested but is currently quite high  More work is needed to give electronics the stability to make this an unlikely event

Risks Optics Slow misalignment of the optics  Misalignment of the optics will cause errors in position reading  If these errors are significant the target will not be able to actuate As much long term testing as time allows will be carried out

Risks Radiation Risks from radiation damage are  Failure of glue holding magnets together  Damage of optic fibres  Failure of magnets  Failure of potting material An initial assessment of the radiation levels to be expected in a years running have been done using FLUKA Further work needs to be done on the implications, but it seems likely that the magnets will need replacing every year

Risks Schedule There is also a risk from some component not being ready in time for tests/installation  Stator not ready  Shuttle/shaft not ready  Optics not ready  Power electronics  Control electronics Highest risks for July tests are the shaft and the optics Highest risk for Sept tests is the electronics Risks for going into ISIS in November will need to be judged on the basis of the acceptance criteria

Risks to meeting specs There is also a risk that we will not be able to meet the specs  Inability to pulse at 1 Hz due to heating of the coils This is of concern and needs to be investigated further  Inability to achieve the accelerations required We will have a better idea once we have the full power driver electronics but current results mean we are optimistic

Conclusions Significant progress has been made in identifying the risks for target operation More work needs to be done to understand the likelihood of many of these risks Careful consideration of what procedures can be put in place to mitigate risks is also required