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1 ITPA St Petersburg 20-24 April 2009G.Gorini JET results on the determination of thermal/non-thermal fusion yield from neutron emission spectroscopy.

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Presentation on theme: "1 ITPA St Petersburg 20-24 April 2009G.Gorini JET results on the determination of thermal/non-thermal fusion yield from neutron emission spectroscopy."— Presentation transcript:

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2 1 ITPA St Petersburg 20-24 April 2009G.Gorini JET results on the determination of thermal/non-thermal fusion yield from neutron emission spectroscopy Uppsala University Istituto di Fisica del Plasma “Piero Caldirola”,CNR & Milano-Bicocca University, Milano, Italy EFDA JET Collaborators Giuseppe Gorini on behalf of

3 2 ITPA St Petersburg 20-24 April 2009G.Gorini Issue: Thermal and non-thermal neutron yield (Q value) used nowadays for physics analysis of fusion plasmas (e.g. JET). Not measured. Qnth/Qth desirable measurement on ITER. Can Neutron Emission Spectroscopy determine the thermal and non-thermal neutron yield and their ratio? Here: JET results from selected D discharges with NBI heating.

4 3 ITPA St Petersburg 20-24 April 2009G.Gorini TOFOR neutron spectromer neutrons TOFOR is a new 2.5 MeV Time-Of-Flight neutron spectrometer Optimized for high Rate operation (>200 kHz range)

5 4 ITPA St Petersburg 20-24 April 2009G.Gorini TOFOR neutron spectra Main features in the measured TOF spectrum: Broad component (e.g. due to NBI deuterons) Low energy tail due to neutron scattering Higher energy neutrons: missing in the absence of RF heating #69242, D plasma, NB heating, single injector tof[ns]

6 5 ITPA St Petersburg 20-24 April 2009G.Gorini TOFOR neutron spectra (linear scale) #69242, D plasma, NB heating, single injector

7 6 ITPA St Petersburg 20-24 April 2009G.Gorini NBI in JET Full model in TRANSP

8 7 ITPA St Petersburg 20-24 April 2009G.Gorini TRANSP Input experimental data Simulation of: –Equilibrium –Trasport –Fast ion dynamics –Radiation emission etc (e.g. for diagnostic comparison) NUBEAM

9 8 ITPA St Petersburg 20-24 April 2009G.Gorini NUBEAM Motion of particles Neutral deposition Ionizzation Orbits Collisions and thermalization

10 9 ITPA St Petersburg 20-24 April 2009G.Gorini Control Room Control Room is a MonteCarlo code first developed in 1994. The original system consisted on a C++ library and a few applications whose purpose was the calculation of slowing-down ion distributions and the resulting neutron emission in thermonuclear plasmas. Now it is possible to use the library from within the Python programming language. In fact, one could say the library was designed for being used as a Python module. This gives the user a number of advantages. On the one hand, this allows one to test-drive the library through the interactive Python interpreter and makes it easier to experiment with its features. On the other hand, this enables the user to write simple scripts.

11 10 ITPA St Petersburg 20-24 April 2009G.Gorini Example of spectrum #69625 t = 58 s.

12 11 ITPA St Petersburg 20-24 April 2009G.Gorini TOFOR data Pulse: 69652 P NBI = 13 MW I p = 2.6 MA B T = 2.2 T T= 1.7 keV Chi 2 = 0.98

13 12 ITPA St Petersburg 20-24 April 2009G.Gorini Pulse

14 13 ITPA St Petersburg 20-24 April 2009G.Gorini Missing Neutrons

15 14 ITPA St Petersburg 20-24 April 2009G.Gorini Missing Neutrons

16 15 ITPA St Petersburg 20-24 April 2009G.Gorini Y th /Y nth

17 16 ITPA St Petersburg 20-24 April 2009G.Gorini Role of sight line To what extent is the plasma volume seen by TOFOR representative of the TOTAL volume? Equation: y = a*(x-b) R 2 = 0.98364 a = 1.216 ± 0.02391 b= 0.00269 ± 0.00369

18 17 ITPA St Petersburg 20-24 April 2009G.Gorini Conclusions TRANSP-based accurate simulation of neutron emission spectra with thermal and non-thermal components. Separation of thermal/non-thermal components possible. Accuracy depends on shape difference. On ITER shape will be very different => separation easier.


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