Pellet Charge Exchange Measurement in LHD & ITER ITPA Tohoku Univ. Tetsuo Ozaki, P.Goncharov, E.Veschev 1), N.Tamura, K.Sato, D.Kalinina and S.Sudo National Institute for Fusion Science 1)Graduate Univ. for Advanced Studies

● Direct measurement of energetic particles in plasma （ proton, alpha etc. ） ● Background neutral for charge exchange is required in passive measurement Difficult to obtain central information due to low back ground neutral around the plasma center. Double charge exchange is necessary to measure  -particle Line integration →Pellet Charge Exchange (PCX) by combination of TESPEL & CNPA PCX has been tried in TFTR for  -particle measurement New results can be obtained even in non-DT plasma device →Diagnostic development (1) Establishment of the PCX technique for proton (1/4 mass of  ) (2)Try helium ion measurement by using PCX (3) PCX in ITER Pellet Charge Exchange Measurement

Diagnostic Principle of PCX d l = D t i ･ v pel (Typically 100μ s ) By measuring the charge exchange particle just behind the pellet trajectory, the time trace of the particle emission can be translated to the spatial distribution. v pel =500m/s→ 5cm Corresponding to the ablation diameter

Experimental Apparatus CNPA Viewing Cone Pellet Injection Axis Compact NPA ＣＮＰＡ（ Compact Neutral Particle Analyzer ） Channel 40 Energy resolution Typically several ％ Energy range 0.8 ～ 168 keV Time resolution 100μs

Experimental Setup SD-NPA CNPA&NDD ＳＤ－ＮＰＡ ２５ ～４ ００ keV ２０４８ ch Pitch Ang. ４５～９０ deg 6 cords NBI 4 CNPA TESPEL NDD(Natual Diamond)

Typical CNPA results in ICH plasma ICH+NBI#1 （ ●○ ）、 ICH+NBI#1+#4 （ ■□ ） 、 ICH+NBI#4 （ ▲ △） Closed marks （ ●■▲ ） mean the standard heating, open marks （ ○□ △） mean the central heating of ICH. The difference of both cases is remarkable in the ICH+NBI#1. Particles from NBI#4 is also obviously observed. NBI#1 ICH#5 NBI#4 NBI#1 ICH#5 NBI#4 Standard heating Central heating

Difference of the resonance positions in PCX Rax=3.6,Bt=-1.25TRax=3.6,Bt=-1.375T ICH 2 nd harmonics T Standard heating -1.25T Central heating In T, the flux increase at  =0. ５. However in T, no enhancement of the flax appears. ←Time trace of the charge exchange particle flux during TESPEL injection. Here the time means the pellet penetration depth. The pellet reaches  =0.1. Vertical axis shows the particle energy.

Difference of the resonance positions in PCX(cont.) In the standard heating 、 the flux increases at  =0.5. In the central heating, the flux increase can not be found because the the pellet trajectory is not cross the resonance surface. ICH 2 nd harmonics Standard heating ICH 2 nd harmonics Central heating Standard Central

Difference of the ICH power ICH 2 nd harmonics Standard heating Flux increase is depended on the ICH power. 1.1MW0.74MW 0.6MW0.29MW

NBI#4 Calculation by T.Watanabe NBI#4 Only

SD-NPA scan during ICH long discharge (Vertical sight lines) Case1: Similar pitch angles Flux increase at the resonance surface can be observed in SD- NPA vertical scan. Vertical Energy Time （ =Position ） Vertical

helium detection in CNPA Z Detector

Spot on Detector

Energy loss in Cloud (by Sergeev)

He(ρ) Pellet velocity 440m/s At plasma edge(ρ=1), the helium/hydrogen ratio of is measure by visible spectrometer. We assume that the ratio is at the energy of 11keV （ minimum energy) H He →Scattering of the hydrogen atom

He 3 minority heating experiment He-3 minority experiment had been tried in LHD 9th experimental campaign. He4 was used as the majority target gas. Small increase of the temperature could be obtained because the hydrogen still remained. We have plan to measure the He-3 spectrum/profile in the next experimental campaign. ＩＣＨ ＴiＴi

Problem of PCX in ITER TECPEL Fisher,RSI Large pellet with high velocity is required.  plasma perturbation Small charge exchange cross section of D,T  TECPEL (Tracer EnCapsulated PELlet) low perturbation good spatial resolution no special equipment Li, BeD,T (fuel) Fisher,RSI ITER n e =1x10 20 (m -3 ) Te=Ti=19.7(1-(r/a) 2 )+0.3 (keV)

Neutron and Gamma ray shielding Shield requirement TFTR: 2×10 16 /s Detector position 10m 8x10 8 /cm 2 s Neutron flux in ITER: 10 4 of TFTR 6-inchs (polyethylene)+4-inchs (lead ） neutron reduction 1/100 (TFTR) →45cm(polyethylene)+30 cm(lead ） Medley,RSI(TFTR) ITER Neutron, gamma /cm 2 s on the wall ITER neutron spectrum TFTR neutron shielding

Neutral Particle Analyzer for ITER Scintillator material (prefer thin film in order to reduce the radiation noise) ZnS(Ag) low Ｘ -ray detection efficiency long decay time (70  s) →CsI(Tl) Deliquescence, but to be resolved by aluminum coating for light protection short decay time E||B Detector saturation due to the strong n,  -ray, high detection efficiency TOF(Frascati) Time-of-flight for particle species selection, Low detection efficiency GEMMA(Ioffe) Exchange to light, intermediate detection efficiency Optical fiber Other improvement Reference detector for noise reduction Detector is far from the scintillator by using optical fiber →Shielding 、 reduce the magnetic effect for the photo- multiplier, reduce the radiation noise GEMMA

Summary ● The preliminary demonstration of the alpha particle diagnostics using PCX and SD-NPA has been done. ● The high-energy particle flux enhancement around the resonance surface of ICH can be observed in the standard heating mode of ICH 2 nd harmonics. ● The helium profile measurement has been tried by using PCX. ● PCX in ITER has been presented.