1. ITPA-Moscow 060410 Role of neutron emission spectrometry on ITER and instrumental requirements Göran Ericsson E.Andersson Sundén, A.Combo 2), S.Conroy, N.Cruz 2), M.Gatu Johnson, L.Giacomelli, W.Glasser, G.Gorini 1), C.Hellesen, A.Hjalmarsson, J.Källne, R.Pereira 2), E.Ronchi, H.Sjöstrand, J.Sousa 2), M.Tardocchi 1), and M.Weiszflog Uppsala University [EURATOM-VR], Uppsala Sweden 1) Univ. of Milano-Bicocca and Istituto di Fisica del Plasma [EURATOM-ENEA/CNR], Milan, Italy 2) Instituto Superior Técnico [EURATOM-IST ], Lisboa, Portugal. 1 CONTENTS OF PRESENTATION 1 Introduction 2 ITER parameters from n spectrometry 3 Examples of n spectrometry results 4 NES capabilities (single sight-line) 5 LOS and interface considerations 6 Conclusion

2. ITPA-Moscow 060410 1Neutron diagnostic systems and functions Neutron diagnostics based on measurement of: Neutron inclusive flux:  n Neutron collimated flux: F n - cameras for neutron emission tomography - neutron emission spectrometry Direct (d) and in-direct (s, scattered) neutron flux components at detector  n =  d +  s and F n = F d + F s Neutron diagnostic systems – multi-parameter measurements: Fission chambers + activation foils Cameras: RNC + VNC Cameras + spectrometer Systems of spectrometers Recent progress spectrometers - Europe: Two new n spectrometers operating at JET – TOFOR, MPRu (UU/VR) Unfolding techniques and detailed calibration of NE213 (ENEA, PTB) JET-EP2 – programs on compacts and digital electronics (ENEA, IST) “Study of Neutron Spectrometers for ITER”, J.Källne (UU/VR) 2

3. ITPA-Moscow 060410 2.Potential information in high power DT : neutron emission spectroscopy + camera _____________________________________________________________________________________ A. Fuel ion kinetics (a) Thermal (T) population (1) reaction rate (R t ) (2) density product n d n t (3) temperature T T * (b) Population with significant supra-thermal (ST) velocity components; as above but (1) up to 4 ST reaction rate components (R ST ) besides R T (2) relative densities of ST velocity components (3) T T and T ST temperatures (if Maxwellian, otherwise slowing down) B. Confined  -particles (1) amplitude of slowing down distribution* (2) pressure C. Collective motion of fuel ion populations (1) toroidal rotation* D. Fusion parameters (1) power P f *; will provide values for dd and dt reactions separately (2) division of P f into thermal and supra-thermal components (3) fuel ion densities in the core (n d, n t and n d /n t *) +) E. Other information (1) the extended spectrum of direct and scattered neutrons from the plasma _____________________________________________________________________________________ * Denotes diagnostic functions listed as essential for measurement on ITER +) Requires simultaneous measurement of 2.5-MeV neutrons from dd and 14-MeV from dt.

4. ITPA-Moscow 060410 3Some selected NES results from JET (MPR) Ohmic phase – thermal T i extracted RF phase – isotropic, anisotropic HE components LE component due to scattered n

5. ITPA-Moscow 060410 Peak (energy) shift shown in pulses with different phasing of RF antenna Alpha knock-on neutrons Count rate  power Spectral components  thermal fraction

6. ITPA-Moscow 060410 Count rate  power Spectral components  thermal fraction

7. ITPA-Moscow 060410 Alpha knock-on neutrons

8. ITPA-Moscow 060410 Peak (energy) shift shown in pulses with different phasing of RF antenna Alpha knock-on neutrons Count rate  power Spectral components  thermal fraction

9. ITPA-Moscow 060410 4NES capabilities (single sight-line) Energy calibration: Independent and absolutecalibration station For toroidal rotation  v tor < 10km/s  E < 3 keV Energy resolution (instrumental, derived, …) For temperatureT i = 4 keV dE/E = 2.5% Sensitivity (S:B) For AKN, RF, TBNS:B > 10000 Time resolution in derived quantities (C cap, LOS,  ) For T i (t)  t < 10 ms For Q th /Q tot  t < 200 ms Separate direct and scattered flux E range, low-E n sensitivitybenchmarking of n transp. calc.

10. ITPA-Moscow 060410 Magnetic proton recoil System in operation at JET Classic nuclear physics instr. Separate tasks: passive n-to-p, passive E det., active p counting f(E n ) from f(x p ) Near-Gaussian response function Abs. calibration in E and  Flexibility, 1 < E n < 18 MeV Separate F d and F s, E bite 20% dE/E = 2.5%,  E < 2 keV (10 -4 ) S:B > 10000 C cap > MHz  t < 5 ms (for T i ) @ 1 MHz Size (>m 3 ), magnetic, efficiency (0.5.10 -4 cm 2 )

11. ITPA-Moscow 060410 MPR instrumental response function (2.5% FWHM @ 14MeV)

12. ITPA-Moscow 060410 Magnetic proton recoil System in operation at JET Classic nuclear physics instr. Separate tasks: passive n-to-p, passive E det., active p counting f(E n ) from f(x p ) Near-Gaussian response function Abs. calibration in E and  Flexibility, 1 < E n < 18 MeV Separate F d and F s, E bite 20% dE/E = 2.5%,  E < 2 keV (10 -4 ) S:B > 10000 C cap > MHz  t < 5 ms (for T i ) @ 1 MHz Size (>m 3 ), magnetic, efficiency (0.5.10 -4 cm 2 )

13. ITPA-Moscow 060410 Neutron detector test and calibration station: MPRw: A w-detector can be developed to improve the time resolution and dynamic range of the diagnostic in, e.g., yield measurements. MPRx: A test/calibration facility for flux detectors in well-characterized F n (E n ) MPR MPRw/x

14. ITPA-Moscow 060410 5LOS considerations Ideal case: 3 spectrometer system co-, counter (NBI) tangential, radial Next best:co-tangential and radial Single instr:TBD Present ITER design: radial LOS? Previous studies: NBI – counter-tangential best, co- OK ICRH – radial best, tangential OK AKN – co-tangential viewing best, radial OK Q th /Q tot – dual LOS best, radial OK Yield – tangential LOS best, radial OK

15. ITPA-Moscow 060410 MPR needs 10 10 n/cm 2 on foil for full performance (n camera?)

16. ITPA-Moscow 060410 6Summary and conclusions High-performance n spectrometer of MPR type: State of the fuel ions: T i, ST comp., AKN, v rot, … Absolute, independent yield determination, Q th /Q tot Absolutely calibrated (E,  ) n detector test station Scattered n flux for n transport calc. benchmarking Interface issues, magnetics THANK YOU !

17. ITPA-Moscow 060410 Summary prel. capabilities and requirements @ 14 MeV MPRTOF14NDDNE213 ”Required” Designed system Conceptual design Best achieved C cap >MHz50 kHz> MHz250 kHz N/A dE/E2.5% 2%1-2%* <2.5%  (cm 2 ) 0.5.10 -4 1.10 -2 1.10 -4 0.1 N/A EE < 2keV ? ? ? <3 keV S:B>10000100 ? 50 >10000  t (T i ) 5 ms100 ms 5 ms?250 ms <100 ms E range1-18 MeV>10 MeV?>13 MeV1-18 MeV § 1-18 MeV Separation dir. – scatt. YesYes?No? Yes * Derived from unfolding, not instumental as for others § Single peaks, prob. not weak (%) LE components

18. ITPA-Moscow 060410 TOF-14 Coincidence measurement, n double scattering Near-Gaussian resp. fcn f(E n ) from f(t n’ ) Calibration with gammas, muons, sources High efficiency, 0.01 cm 2 ? (14 MeV) @ dE/E = 2.5% C cap = 50 kHz (14 MeV) ? Signal:accidentals = 100 (sensitivity)  t < 100 ms (for T i ) Size (>m 3 ), performance, complicated (100’s detectors)

19. ITPA-Moscow 060410 Diamonds (NDD, CVD) Detector in n ”beam” Full E n deposited: 12 C(n,  ) 9 Be Radiation hard, high T oper. dE/E > 2% C cap = MHz Complicated resp fcn - 9 Be*, 12 C(n,n), (n,3  n’) f(E n ) from f(Q) Individual detector calibration Small size, low efficiency Limited experience base Resp.fcn, bandwidth, availability/cost, charge trapping n NDD

20. ITPA-Moscow 060410 Scintillator ”compacts” (NE213) Detector in n “beam” n/  separation (PSD) Complicated resp fcn – H(n,p) single and multiple, 12 C(n,n), inelastic channels Each detector calibrated at accelerator f(E n ) from unfolding Stability monitoring (C n, T, t) P.h. resolution 5-8% dE/E = 1-2% (unfolded) ? Sensitivity 2% (unfolded) ? C cap > 200 kHz ?  t < 250 ms (for T i ) ? Calibration, stability, performance n NE213 n’