1. NPL accelerator facility
Saturday, 10 November 2018
NPL accelerator facility
Steven Judge
National Physical Laboratory

2. NPL 3.5 MV Van de Graaff accelerator
Graphite pile provides thermal neutron field for instrument characterisation, particularly reactor instruments
Low scatter facility enables provision of mono-energetic neutron fields for instrument characterisation

3. Current technical specification
Saturday, 10 November 2018
Current technical specification
3.5 MV Van de Graaff generator
Protons and deuterons, low energy limit = 1 MeV
Beam current 1-80 μA
Monoenergetic neutron fields from 8 keV to 16.5 MeV
Thermal pile: 3x107 neutrons s-1cm-2 in the centre, stability better than 0.25%. Used for instrument calibration and for radionuclide production eg 56Mn
Low scatter hall

4. Additional requirements for new facility
Saturday, 10 November 2018
Additional requirements for new facility
Lower energy beams – down to 150 keV to produce 14 MeV neutrons for fusion related research
Higher energy beams – to produce monoenergetic neutrons in the range 2.5 MeV to 5 MeV
Nanosecond pulse mode
Higher beam current – up to 200 μA desirable
Improved availability – 24 hour operation

5. Saturday, 10 November 2018
Next steps
NPL’s initial proposal is to replace the Van de Graaff generator with a broadly equivalent accelerator.
Involvement of academic and industrial partners in establishing and running a new facility is essential.
How we go about this – to be decided…