CEC-ICMC 2015 - Timetable, Abstracts and Presentations

Comparison of coil cooling techniques for a 25 MeV compact superconducting cyclotron

Not scheduled

15m

JW Marriott Starr Pass Resort

Contributed Oral Presentation CEC-06 - Superconducting Magnet Systems

Speaker

Mr Sundeep Ghosh (Variable Energy Cyclotron Centre)

Description

A compact superconducting cyclotron is being designed at Variable Energy Cyclotron Centre, Kolkata, India. This cyclotron shall be dedicated for medical applications specifically in the field of nuclear medicine and therapy. The cyclotron magnet will be made of NbTi superconducting coils wound on an Aluminium former. The coils will be segregated in two halves on either sides of the median plane. Each half will consist of four solenoid coils of different diameters and lengths. In addition, there will be four sectors each comprising of three sector coils of different sizes. These sector coils will provide the azimuthally varying component of magnetic field. This cyclotron is unique in its composition since it does not contain any iron. The average magnetic field calculated is 1.74 T and the maximum extraction energy will be 25 MeV which is sufficient for production of 99mTc from Mo. The set of coils will be supported with glass-epoxy links attached to the former to reduce conduction heat load to the coils. Two different methods of cooling have been proposed for the cyclotron. In the first method, the superconducting coils will be conduction cooled with the help of breaded Copper strips directly connecting the coil former walls with the cold head of cryocoolers. The second one is buoyancy induced recondensation cooling method. In this case liquid helium will pass through channels attached to the former surface to take the heat away from magnet and will get recondensed back in cryocoolers placed outside the cryostat. This paper presents the detailed design methodologies of both the cooling techniques and a comparison has been drawn in terms of temperature distribution in coils and rate of heat transfer achieved at steady state.