Fast neutron beams. Andy Buffler and Ricky Smit. in support of the Radioactive-Ion Beam project at ithemba LABS

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1 in support of the Radioactive-Ion Beam project at ithemba LABS Fast neutron beams Andy Buffler and Ricky Smit Dept of Physics University of Cape Town ithemba LABS

2 Use of fast neutron beams in four broad areas (inter related) Metrology Biological work Space science Neutron physics Longstanding collaboration between UCT, itl and the PTB Physikalisch Technische Bundesanstalt, Germany

3 Fast neutron beam facility (D line) ns pulsed proton beams of high current and reliable pulse selection unique multi angle fan collimator and long flight paths (up to 10 m)

4 Quasi monoenergetic neutrons are obtained either: (a) by selecting the TOF peak (if t < few ns); or (b) by using the (0 and 16 ) difference method. Neutron spectra (measured by TOF), from 100 MeV protons on a nat Li target: Spectral neutron fluence, normalised to the same number of protons Φ E / N mon (arb. scale) nat Li(p,n): E n / MeV Φ E / N mon (arb. scale) nat Li(p,n): difference beam E n / MeV 4

5 Neutron Metrology in the energy range 40 to 200 MeV itl D line is now a recognized reference field by the European Radiation Dosimetry group with increasing demand for usage. Uppsala becoming a medical facility only Only other fast neutron facility in Japan but only really offers beams in the range 200 to 400 MeV.

6 Secondary neutron spectra in space and flight altitudes Galactic Cosmic Radiation Dose rate at 10 km: 5 µsv/h µ (5%), n(45%), γ+e(35%), p(15%)

7 EURADOS run in 3 weeks time Users from 10 institutions (itl, UCT, PTB, DLR/CAU, NPI, UAB, ISRN, POLIMI, HPA and PSI) with 17 instruments (πdos, NAVIDOS 3, AMIRA, Phoswitch IRAS, MSL RAD, N.N., Liulin, HAWK, NPI CR39, SEU Device, PADC Phar, ISRN CR39, POLIMI CR39, HPA PADC, PSI CR39)

8 Radiation Assessment Detector Launch Window: Nov Dec Mars mission (NASA) Tested with itl neutron beams.

9 South African space work Sumbandila satellite launched in 2009 used mainly for high resolution imaging Government interest in SunSpace SunSpace/US and UNM want electronic testing for space use Will give local space effort international competitiveness East London - SA

10 Biological work Studies into neutron damage to chromosomes in blood Count dicentrics and ring formations after neutron irradiation New method sensitive to 40 millisv All measurements done with the same person s blood

11 Fast neutron beam use at ithemba LABS Now supported by dedicated detectors, electronics, data acquisition systems (both analogue and digital), and increased numbers of students. Reminder of why more beam required Neutron beams are secondary beams Neutron detection not as efficient as it requires interaction with nucleus Neutron detectors usually also sensitive to gammas as well therefore backgrounds can be high

12 Possible future second neutron beam vault False floor Open geometry Beam stop below Vault symmetric Lower background

13 Positron Emission Particle Tracking Andy Buffler and Indresan Govender Department of Physics, University of Cape Town CENTRE FOR MINERALS RESEARCH Dept of Physics The Minerals to Metals Initiative Department of Chemical Engineering

14 Positron Emission Particle Tracking (PEPT) PEPT is a technique which tracks the trajectory (x, y, z, t) of a tracer particle which has been labelled with a radionuclide that decays via positron emission. y tracer particles range in size from a few millimetres to below 0.1 mm and may be moving within a very aggressive environment tumbling mill, flotation cell, gaseous flow system, z x PEPT allows the visualization of the path line of the particle, measured within the field of view of a PET camera.

15 The EXACT3D PET scanner at PEPT Cape Town has over detector elements.

16 A wide and diverse research programme (mainly minerals-related) at PEPT Cape Town Experiments completed within the areas of Comminution tumbling mills and IsaMills Jigging Flotation Packed beds and developments in Tracer manufacture and labelling Data analysis Dynamic PET imaging

17 Comminution: motion within tumbling mills Tumbling mill (300 mm inner diam., length 270 mm) 40% filled with 3 mm glass beads and rotating at 20% of critical speed average velocity field CENTRE FOR MINERALS RESEARCH

18 Flotation: Tracking particles in flotation froths Trajectory of a 190 μm particle in a cylindrical flotation vessel

19 Tracer research for PEPT Nick van der Meulen Etienne Vermeulen Michael van Heerden Cong Lui Dept of Physics The Minerals to Metals Initiative Department of Chemical Engineering critical feature of PEPT is that realistic tracers may be labelled minerals, tough resins, glass beads, wide ranging research programme into tracer manufacture and labelling any expansion of the radioisotope production capability at ithemba LABS will be of benefit to this work.

20 PEPT users in 2010/2011 (students in red) Dept of Physics Indresan Govender Andy Buffler Steve Peterson Angus Morrison Matthew Bickell Michael Malahe Marius Hromnik Sherry Bremner CENTRE FOR MINERALS RESEARCH The Minerals to Metals Initiative Department of Chemical Engineering Aubrey Mainza J-P Franzidis André vd Westhuizen Sue Harrison Lawrence Bbosa Daramy Kallon Angus Morrison Hartmut Brodner Marc Brighton David Parker Jan Cilliers Katie Cole Barry Shean Malcolm Powell Jan van Schoor Bongi Ntsoelengoe Michael van Heerden Cong Lui Nick van der Meulen Etienne Vermeulen Clive Naidoo Richard Newman Kobus Slabbert Katie Barns Hans de Waal Bruce Spottiswoode Natasia Naude Wynand Roux Neil Jarvis