Practical Cyclotron Problems

Dear SirI'm servicing cyclotrons for the medical industry and lately I had a severe incident.The cyclotron has an electromagnet powered by a Magnet Power Supply MPS.Water cooling on the magnet was running only when I was running the cyclotron.The ramp-up speed of the electromagnet was set to 3 Amperes/sec to a final value of 450 Amperes.Two months ago I replaced the MPS and the water cooling to new versions. Now water cooling runs 24/7 on the magnet and the ramp-up speed is 9 Amperes/sec.I have now found out, that I need to run my electromagnet higher, i.e 460 Amperes to achieve my target.Measured the voltage difference on the two coils and found smaller voltage on one of the two coils, which means that I got shorted turns on the coil. Which means smaller resistance and thus higher current.I believe that the colder magnet (since the water cooling is running 24/7) and the much higher ramp-up speed are related to this coil failure.I would really appreciate your thought or opinion on this magnet behavior.Do you think that lower coil temperature and higher ramp-up speed could affect the coil ???? or it is just a coincidence ????Kyprianidis TheofilosCyclotrons Engineer
- Theofilos Kyprianidis (age 48)
Athens, Greece

My first guess is that the continuous water cooling is not a problem. The high ramp up speed may have created quickly changing stresses that broke some insulation and created a little short.

I'll try to find a better magnet expert to run these questions past for further thoughts.

Mike W.

(published on 10/22/2017)