jet neutron, gamma & particle diagnostics · 2013-05-30 · jet neutron, gamma & particle...

D. B. Syme et al, EIROForum May 2013

JET Neutron, Gamma & Particle JET Neutron, Gamma & Particle

DiagnosticsDiagnostics

Brian SymeBrian Syme

EIROForumEIROForum 2013, May 20132013, May 2013


AcknowledgementsAcknowledgements

JET Neutron, Gamma & Particle DiagnosticsJET Neutron, Gamma & Particle Diagnostics

D.B. Syme1, S. Popovichev1, V. Kiptily1, L. Giacomelli2, S. Conroy3, P. Beaumont1,

M. Santala4, G. Ericsson3, M. Weiszflog3, A. Hjalmarsson3, C. Hellesen3,

H. Henriksson3, G. Gorini2, M. Tardocchi2, R. Pereira5, A Fernandez5, M. Riva6, F. Belli6

and JET EFDA contributors*

[email protected], [email protected], Culham Science Centre, Abingdon, OX14 3DB, UK

1EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB, UK2 EURATOM-CNR Fusion Association, Istituto di Fisica del Plasma "Piero Caldirola“, CNR, Milano, Italy

3 EURATOM-VR Fusion Association , Department of Physics and Astronomy, Uppsala, Sweden4 EURATOM-Tekes Fusion Association, VTT Technical Research Centre, P.O. Box 1000, FI-02044 VTT, Finland

5 EURATOM-IST Fusion Association, Instituto de Plasmas e Fusão Nuclear / IST

Av. Rovisco Pais, 1049-001 Lisboa Portugal6 Associazione EURATOM-ENEA sulla Fusione, C.P. 65, Frascati I-00044, Roma (Italy)

* See the Appendix of F. Romanelli et al, Proceedings of the 24th IAEA Fusion Energy

Conference 2012, San Diego, USA.


Fusion energy researchFusion energy research

-- Ions, neutrons and fusion productsIons, neutrons and fusion products

Fusion powerFusion power has the potential to provide energy in the futurehas the potential to provide energy in the future

in a sustainable way in a sustainable way –– reactions between hydrogen ionsreactions between hydrogen ions

–– 22D + D + 22D D ��33He (0.82 He (0.82 MeVMeV) + ) + n n ((2.452.45 MeVMeV)) 50%50%

–– �� 33T (1.11 T (1.11 MeVMeV) + p (3.02 ) + p (3.02 MeVMeV) 50%) 50%

–– 22D + D + 33T T ��44He (3.5 He (3.5 MeVMeV) + ) + nn ((14.114.1 MeVMeV))–– 22D + D + 33HeHe ��44He (3.6 He (3.6 MeVMeV) + p (14.7 ) + p (14.7 MeVMeV))

–– 33T + T + 33T T ��4He + 4He + 2n2n <11.3 <11.3 MeVMeV>>

DD--T is favouredT is favoured: : -- Best yield at lowest temperature (ion energy)Best yield at lowest temperature (ion energy)

Need Need containmentcontainment at high temperature and densityat high temperature and density

In the SunIn the Sun –– Gravitational containmentGravitational containment

On Earth On Earth –– Magnetic containment Magnetic containment

–– ‘‘TokamaksTokamaks’ like JET are now favoured’ like JET are now favoured

–– Maximise Fusion Product = Maximise Fusion Product = ni.Tini.Ti..ττee

Arising points for DiagnosticsArising points for Diagnostics–– Neutrons measure the fusion yield Neutrons measure the fusion yield –– directlydirectly

–– Same number of p, Same number of p, 33T ions as T ions as nn in a D,D plasma in a D,D plasma

–– There are There are 33TT ions + 14 ions + 14 MeVMeV neutrons, even in D,D plasmasneutrons, even in D,D plasmas

From Triton From Triton ‘‘burnupburnup’’

And tritium adsorbed in the wallsAnd tritium adsorbed in the walls

. 1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1 10 100 1000

kT (keV)

cro

ss s

ectio

n (

ba

rn)

D-D D-TD-3HeT-T

10

1

10 -1

10 -2

10 -3

10 -4

MASTMAST


The present world leading machine is The present world leading machine is

JETJET ((JJoint oint EEuropean uropean TTorusorus), A European project, operated ), A European project, operated by by EuratomEuratom

16 MW peak D16 MW peak D--T fusion power and closest approach to T fusion power and closest approach to breakbreak--even (Q~1) [1997]even (Q~1) [1997]

Flexible machine with 25 years operation, Flexible machine with 25 years operation,

JET machine parameters and & plasma conditions are JET machine parameters and & plasma conditions are nearest to those of the next step = ITERnearest to those of the next step = ITER (now in build)(now in build)

<NBI, ICRH & LH heating types, Be, Tritium facilities ><NBI, ICRH & LH heating types, Be, Tritium facilities >

Fusion energy researchFusion energy research

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 2 4 6 8 10

radial distance from toroidal axis (m)

vertical distance from m

idplane (m

)

T-3MASTJETITER


–– At a laboratory scale: neutrons are a diagnostic tool At a laboratory scale: neutrons are a diagnostic tool

used for used for measurement of plasma parametersmeasurement of plasma parameters

Neutron DiagnosticsNeutron Diagnostics

Reactions in DReactions in D--D and DD and D--T research and power devices produce neutrons:T research and power devices produce neutrons:

2D + 2D � 3He + n 3.27 MeV

[� 3T + p 4.03 MeV ]

2D + 3T � 4He + n 17.6 MeV

YYnn yield yield (t)Fission chambers, Fission chambers,

diodes, diamondsdiodes, diamonds

YYnn YieldYield

N spectrumN spectrum

Elemental foils Elemental foils

irradiation probesirradiation probesActivationActivation

YYnn yield yield (t)

nnionion profileprofileScintillatorsScintillators

Neutron (rate) Neutron (rate)

monitoringmonitoring

N spectrum (t)N spectrum (t)

TTionion (t)(t)

egeg TimeTime--ofof--flight,flight,

Magnetic proton Magnetic proton

recoil & CNS typesrecoil & CNS typesSpectrometrySpectrometry

MeasurementMeasurementApparatusApparatusTechniqueTechnique


Neutron Diagnostics measurements:

• Time resolved neutron yield• Time integrated absolute neutron yield• Radial profile of the neutron emission• Neutron energy spectra.

+ recently a range of Fast Ion Diagnostics• Fast ion loss detectors (FILD)• Fusion gamma diagnostics• Alfven Eigenmodes Antennas • Neutral Particle Analyserseutral Particle Analysers

Measurement ChallengesMeasurement Challenges•• 10 s pulses/20 10 s pulses/20 minsmins, N, N--yield range: 10yield range: 108 -- 10102020

•• Extended N source (Extended N source (ToroidalToroidal, R~3m, H~1, R~3m, H~1--2m)2m)

•• Magnetic Fields, EM interference, Mechanical Magnetic Fields, EM interference, Mechanical

Vibrations Vibrations

•• High N, X & GammaHigh N, X & Gamma--ray backgroundsray backgrounds

•• Radiation Damage levels, Restricted accessRadiation Damage levels, Restricted access

•• [D,T equipment to be remotely handled][D,T equipment to be remotely handled]

Complementary TechniquesComplementary Techniques are always required are always required

[Different views, shielding, responses, sensitivities, +/[Different views, shielding, responses, sensitivities, +/––’’s]s]

JET Neutron Diagnostics JET Neutron Diagnostics -- Measurements & ChallengesMeasurements & Challenges

From its beginning (1983), JET has had an extensive set of Neutron Diagnostics

Fields of View


TimeTime--resolved Total Neutron Yield Monitor resolved Total Neutron Yield Monitor

(2.45 (2.45 MeVMeV plus 14 plus 14 MeVMeV both included)both included)

3 pairs of fission chambers - U235 & U238

� Located around JET (on the limbs in Oct. 2, 8 and 6).� Wide Range of neutron yields: 1010 to 1020 n/s� Electronics: (All analogue)

HV, preamps, log amps, high linearity� Absolutely calibrated to <10%, periodic verification

JET Time-Resolved Neutron Yield Monitors

• Threshold (n,p) and (n,a) reactions in SiSi diodesdiodes & Diamonds• Range: 1013 - 1018 n/s

Time-resolved 14 MeVNeutron Yield Monitor


JET Neutron Yield Monitors - Locations

Oct 8Oct 6

Oct 3

Oct 2

Oct 8

FC- D1FC-D3

FC- D2

Oct 1

Irradiation End 3 Upper

Fission Chamber - FCOct 7

Oct 5

Oct 4

Oct 6 Oct 8Oct 6

Oct 3

Oct 2

Oct 8

FC- D1FC-D3

FC- D2

Oct 1

Irradiation End 3 Upper

Fission Chamber - FCOct 7

Oct 5

Oct 4

Oct 6


•• 88 Irradiation ends located in 5 octants :

• Capsules containing sample foils are delivered and retrieved pneumatically

•• CConventional gamma-radiation measurementsRange: 1014 to >1020 n/s

most widely used reactions at JET:DD - 115In(n,n’)115mIn, DT - 28Si (n,p)28AL, 63Cu(n,2n)62Cu, 56Fe(n,p)56Mndetectors : 3 NaI, HpGe (absolutely calibrated)

•• CCounting of delayed neutrons - Range 1014 to >1020 n/s

After N,fission reactions in (235U,238U,232Th) foilsGives DD neutron yield, when Y(DD)>> Y(DT)detector system: 2 stations with six 3He counters

• Accuracy typically ~ 8-10%for both DD and DT neutron yields delayed neutron measurements can give 7%

JET Neutron Yield Monitors - Activation

JET Activation System

(Octant 3 Upper) Irradiation End – I.E

JET Mechanical Support Structure

Vaccum Vessel (Double-walled)

Iter-Like Wall (Plasma-facing)

JET Octant 3 Cross-section


Calibration of Fission Chamber vsActivation system

Typical time dependence of 7 sec pulse

JET Neutron Yield per dayJET Neutron Yield per day

(1984(1984--2010)2010)

Blue = Total Yield,Blue = Total Yield,

Red= D,T YieldRed= D,T Yield

Neutron Yield Monitors - Data

J E T D a i ly N e u t ro n Y ie ld s 1 9 8 4 -2 0 0 9

1 .0 E + 1 2

1 .0 E + 1 3

1 .0 E + 1 4

1 .0 E + 1 5

1 .0 E + 1 6

1 .0 E + 1 7

1 .0 E + 1 8

1 .0 E + 1 9

1 .0 E + 2 0

198

4

19

85

198

6

19

87

198

8

19

89

19

90

199

1

19

92

199

3

19

94

199

5

19

96

19

97

199

8

19

99

200

0

20

01

200

2

20

03

20

04

200

5

20

06

200

7

20

08

200

9

D a te

Neu

tro

ns

/ d

ay

D D -n e u t r o n s

D T n e u t r o n s


JET Neutron Yield JET Neutron Yield -- CalibrationCalibration

Need absolute measure of fusion rateNeed absolute measure of fusion rate

Need Absolute Calibration of Neutron EmissionNeed Absolute Calibration of Neutron Emission

versus a calibrated neutron source in the versus a calibrated neutron source in the torustorus, , egeg 252252--CfCf

Last done in 1985Last done in 1985--9, for the Fission Chambers only, 9, for the Fission Chambers only,

<All<All--metal JET. No metal JET. No DivertorDivertor, Plasma Centre was lower by 30 cm.>, Plasma Centre was lower by 30 cm.>

Calibration extended by a succession of calculations, since thenCalibration extended by a succession of calculations, since then

How it has been set up in 1985/9

1985/9 Method:

Pull a strong calibrated

neutron source round

the torus in a tube.

Observe response from

external Fission

Chambers per source

neutron => calibration


March 2010 - During ShutdownJET 1985

The JET Experiment The JET Experiment -- Changing since 1983Changing since 1983

JET 1991

Inside JET 1985 2011 JET ITER-Like WallInside JET 1994


Auxiliary Shield

In ISO container

Oct5 Boom Tent

Transport Flask

In Loading BayTCTF Tent Operational Shield

Mascot

11 m Port to Port

Contingency Provisions Normal Operations

Source loading & deploymentSafe source storage

R-H Deployment Environment


JET JET NNeutroneutron SSourceource Calibration Calibration -- 20132013

a) 40 steps round vessel in plasma centre locations

b) 1 set of radial & vertical scans at a port

c) Scan under Irradiation End – First direct calibration

d) Basket scan: 40 steps x 5 rings round vessel - with +/- 50 cm in Z, R

e) Direct Comparison of Activation and Fission Chamber methods for 252Cf

Improves old JET calibration

Precursor to JET D,T Calibrations

Addresses many questions relevant to ITER Calibrations

eg Corrections for –

Non symmetric sources

Scattering effects, eg source holder & support structure

Point vs 3D calibrations

Torus practicalities

Direct calibration of JET neutron monitors, versus a standard 252Cf source in-torus

Deployment plan on right


Progressive reduction of Raw FC neutrons observed per JET neutroProgressive reduction of Raw FC neutrons observed per JET neutronn

as JET ports regions became congested and Limiters were addedas JET ports regions became congested and Limiters were added

Note: No information from this on the effect of recent torus inner wall changes,

as there was no neutron calibration in the earlier ‘carbon wall’ period

Reduction in FC rate

per JET neutron

X 2 in 29 years

FC Oct 6: Raw Counts: Historical Comparison to 1984 data

(for the same Cf Neutron Rate)

Note: this is not a

calibration coefficient


M. Adams et al., NIM, A 329 (1993)

Two cameras:Two cameras:

Vertical: 9 linesVertical: 9 lines--ofof--sightsight

Horizontal: 10 linesHorizontal: 10 lines--ofof--sightsight

FanFan--shaped array of shaped array of remotely adjustable remotely adjustable collimators collimators with two apertures.with two apertures.

Space resolution: Space resolution: ~8 ~8 (or ~15)cm(or ~15)cm (in the centre(in the centre

Detectors:Detectors:

-- NE213 liquid NE213 liquid scintillatorsscintillators (2.5 and 14 (2.5 and 14 MeVMeV)) + PSD; + PSD;

-- Plastic Bicron418 Plastic Bicron418 scintillatorsscintillators (14 (14 MeVMeV))

--CsI(TlCsI(Tl) photodiodes) photodiodes (Hard X rays and g emission (Hard X rays and g emission 0.2<0.2<EgEg<6 <6 MeVMeV).).

DAQ: Recently converted from analog to digital

Plasma coverage allows 2D pseudo Plasma coverage allows 2D pseudo -- tomographytomography

CoversCovers both DD and DT regimes of operationboth DD and DT regimes of operation

JET Neutron Profile Monitor & Gamma Camera

Neutron detectors are absolutely calibratedNeutron detectors are absolutely calibrated


KN3 Basic Data –

Neutron Yield Profile as Line Emission Profiles

See variations in position and peaking of the

neutron emission (profile of fusion ‘burn’)

JET Neutron Profile Monitor JET Neutron Profile Monitor -- DataData

Data can be -

• Used as: plasma N emission profile vs time

• Compared with: models of plasma emissivity, fast ion distributions, etc.

• Converted to: pseudo-tomographic images14 MeV Bicron Detectors in TTE

S. Popovichev et al., 31st EPS Conf. on Plasma Physics, London, UK (2004).

Vertical cameraVertical camera

has demonstrated has demonstrated

asymmetries in the asymmetries in the

neutron emission neutron emission

profiles for some profiles for some

experimentsexperiments

–– large orbit large orbit

trapped ions can trapped ions can

produce neutronsproduce neutrons


Profile Monitor Profile Monitor -- Recent Results Recent Results -- Digital DAQDigital DAQ

#82723 (NBI = 21 MW), KN3N#82723 (NBI = 21 MW), KN3N

Raw Data, not yet corrected for variations in detector efficiency, etcDigital DAQ by ENEA association

Vertical

Camera

Horizontal

Camera


Spectrometry Principles for Neutrons

Measurement of neutron energy - by transfer of momentum/energy from neutron to recoil proton

a) Measurement of recoil proton momentum in dispersive magnetic spectrometer (MPR)

b) Timing of recoil neutron (TOF) from scattering detector to 2nd

detector (TOFOR)

b’) Direct measurement of recoil proton energy from thin foil - in SSD detector (not shown)

c) Proton absorption by scintillator -proportional conversion to light, then to an electronic signal, amplification & DAQ processes -‘compact neutron spectrometer’ Fig. Giacommeli et al, Nucl. Fusion 45 (2005)


D,D Neutrons - Time of Flight Spectrometer - <TOFOR>

Vertical Line of sight

Sited in Roof Laboratory above Oct 8

Range: 1014-1017 n/s

Neutron Spectrometers & Lines of SightNeutron Spectrometers & Lines of Sight

Diagnostics by VR association (Sweden)



D,T (D,D) neutrons - Magnetic Proton Recoil spectrometer <MPRu>

Plasma self-heated thermal peak (top)

- Peak width – ion temperature

ICRF-Heated D,T Plasma (bottom)

- Broadened Thermal peak - Ion Temperature

- and High Energy Neutrons

Horizontal - Tangential LoS,

Looking from Oct 4 to Oct 7

Sited in a Separate Shield in the Torus Hall

Diagnostics by VR association (Sweden)



Compact Neutron Spectrometer - <CNS>

For D,D & D,T Neutrons

Horizontal - Tangential LoS,

Looking from Oct 7 to Oct 2

Sited in Bunker Outside Torus Hall

CNS

Range: 1014-1017 n/s


NE213 CNS Spectrometer Data and Digital DAQ

Ne213 Spectrometer (left) and StilbeneScintillators, sharing an annular neutron field in a JET bunker

The NE213 response function was measured at PTB, in an ENEA project

NE213 scintillator detector (BC501A) with a 207Bi γ source for long term stability monitoring & LED for short-time PM gain corrections.Digital DAQ for PSD, Pulse Height analysis, and event time stamping

Pulse-height

Spectrum

PSD

data


Unfolded broad NBI-induced

neutron energy spectrum

(D,D)

Simultaneous Energy Spectra

(ex Pulse Height Distributions)

From 2.5 MeV Neutrons (D,D)

And 14 MeV neutrons (D,T)

NE213 CNS Spectrometer Data


SystemsSystems JET JET

DetectionDetectionCapabilitiesCapabilities Neutron Neutron

range range

10101414 to >10to >102020

n/sn/s

Liquid Liquid scintillatorsscintillators NE213 NE213

Plastic Plastic scintillatorsscintillators BC418BC418

CsICsI ScintillatorsScintillators for for

GammaGamma--CameraCamera

Time-resolved

total emission

(rate)

Time-integrated

emission

N Profile Monitor

(2D-cameras)

Spectrometers

All En: fission counters

14 MeV: Si diodes,

CVD

dYn/dt: Wide range,

fast response,

Redundancy

MHD, T Burnup, nD/nE

Foil activation &

count

Gamma or neutron

Absolute N yields,

Yield Calibration in

D,D & D,T

TOFOR (VR)

NE213 (and Stilbene)

Magnetic proton recoil (VR)

Neutron emission Spectra,

Ion Temperature (Ohmic), NBI -

Thermal & Beam-plasma yields,

Hot ions in ICRH heating,

nD/nE in D,D - or nnfuelfuel/n/nee in D,Tin D,T

dYn/dt(R, Z), Total N yield,

N Emission Tomography,

nD/nE, T Burnup,Fast particle confinement

1010 to 1020 n/s

1014 to >1017 n/s

1015 to >1017 n/s

Summary: Current JET Neutron Diagnostics Systems


Fast ions occur in the plasma from -

fusion products: p (3 & 15 MeV), T (1 MeV), 3He(0.8 MeV), αα ((3.5 MeV3.5 MeV))

ICRH-accelerated [Fuel and product][Fuel and product] ions: H, D, T, 3He, 44HeHe

γ-ray emission is produced by fast ion nuclear reactionswith bulk ions and impurities in the plasma (mainly C, Be)

GammaGamma--ray ray ‘‘fingerprintfingerprint’’ identifies fast ions > key energies, identifies fast ions > key energies, egeg

α-particle diagnosis at JET is based on the 9Be(α,nγ)12C reaction

Fast deuteron detection in the old JET was based on the12C(d,pγ)13C reaction - now Be

reactions, mainly Be(d,nγ) and Be(d,pγ)

NaI & BGO detectors previously used, (plus CsI in the profile monitor)

Recent additions: LaBr3 & HpGe

JET Gamma Spectroscopy - (Confined Fast Ions)


γγγγγγγγ--ray ray spectrometersspectrometers - Lines of SightLines of Sight

BGO

Original Capabilities: (Original Capabilities: (AnalogAnalog DAQ)DAQ)

NaI(TlNaI(Tl):): energy resolution, ∆E/E ≈ 8%

Slow: decay time ~ 250 ns

Recent RF DAQ system allows up to 1

MHz Pulse Height Analysis

•• LaBrLaBr33 (or BrilLanCe): ∆E/E ≈ 3%,

Decay times - < 20 ns

DAQ allows up to 2 MHz PHA

•• QuasiQuasi--tangential BGOtangential BGO--spectrometer:spectrometer:front and rear collimators to improve S/B ratio

BGO, NaI(Tl), LaBr3, HpGe

Recent Upgrades: Recent Upgrades: CNR & IST ledCNR & IST led

BGO: energy resolution, ∆E/E ≈ 12%

Best detection efficiency!Slow: decay time ~ 300 ns ⇒ 1MHz PHA

a link to

results

with

carbon

wall

•• HpGeHpGe:: ∆E/E ≈ 0.1%, DAQ to1 MHz

Neutron Sensitive specific tasks

•• Gamma Camera:Gamma Camera: 19 LoS indicated: Energy Windows, now Spectrometers

•• DAQ: Upgraded from DAQ: Upgraded from AnalogAnalog -- DigitalDigital


GammaGamma--Ray Spectrometers Ray Spectrometers -- Vertical Vertical LoSLoS

Neutronattenuators

Sliders

LaBr3

NaI(Tl)

HpGe

(a)

Concrete

shielding

Precollimator

TOFOR

Coils Horizontal

diagnostic

port

Upper vertical

diagnostic port

Support structure

and radiation shielding

Divertor region

Roof

laboratoryJG09.419-3a

3 Detectors and 2 neutron filters on sliders - Choose 1 & switch into the N/G beam

BGO or LaBr3 above 6LiH Filter in 2nd vertical path (not shown)

G Specs


JET Gamma Spectroscopy & Gamma Emission Profiles

Kiptily V.G. Kiptily V.G. et al et al 2002 2002 NuclNucl. Fusion . Fusion 42 42 999999 Alpha Diagnostics Alpha Diagnostics Kiptily V.G. Kiptily V.G. et al et al Nuclear Fusion 45 (2005) L21Nuclear Fusion 45 (2005) L21

3rd IC harmonic 4He-beam ion acceleration experiments


0 2 4 6 8 10 12 14 16 18 200

50

100

150

200

250

verticalhorizontal

Co

un

ts

Channel number

#81852

0 2 4 6 8 10 12 14 16 18 20

0

100

200

300

400

500

600

700

Coun

ts

Channel number

Gamma-ray background count rates

during NBI heating phase

in ## 81852,81853, 81855 & 81857

γγ--rayray emission profile from Gamma Cameraemission profile from Gamma Camera

Be-profile is needed to obtain the spatial distribution of energetic ions

NBI phase ICRH phase

Digital DAQ by IST Association

(From spectroscopic data obtained with the(From spectroscopic data obtained with the new digital DAQ)new digital DAQ)


200 400 600 800 1000 1200 1400 1600 1800 2000

0

50

100

150

200

250

300

350

400

12C(d,pγ)

13C

9Be(α,nγ)

12C

3.089 MeV

4.439 MeV

dN

/ d

n

channel number

1700 1750 1800 1850

20

40

609Be(α,nγ)

12C

4.439 MeV

dN

/ d

n

Channel number

Kiptily et al NF 50 (2010) 084001

4He-beam ions was accelerated

by ICRF in the 4He-plasma

The Doppler broadening due to

nuclear reactions between 4He

and Be impurity has been

measured for assessment of

effective “temperature” <T4He>:

∆Eγ ≈ Eγ0(VR/c) cos θ

VR – recoil velocity which is

depend on the 4He-ion

velocity

γγ--ray ray spectrum from HpGespectrum from HpGe--detector: detector: Doppler broadeningDoppler broadening

44HeHe--acceleration experimentsacceleration experiments


γγγγγγγγ--ray ray spectrum from spectrum from HpGeHpGe--detectordetector : fast a-particle beam

32

E* = 6 MeV

Shape does change with E*

Limited by statistics

Eα = 3 MeV

R

4MeV α

LOS ICRH

2MeV α

Spectrometer

M. Tardocchi et al, proceeding of EPS conference, Dublin, June 2010

M. Nocente et al, Nuclear Fusion 52 (2012)022001

kp in agreement with values found from

analysis of peaks from 12C(d,pγγγγ)13C


Faraday

Cups

Darrow et al. RSI 77 (2006) 10E701

Fast Ion Loss Detectors (1) Faraday Cups

MultilfoilMultilfoil

Faraday Cups Faraday Cups

with energy with energy

resolution for resolution for

lost alphas lost alphas

at 5 poloidal at 5 poloidal

positionspositions

(promising 4He (promising 4He

results)results)

USA (PPPL, USA (PPPL,

CSM), CSM), JOCJOC


Faraday Cups array provides good poloidal and time resolution

• Time resolution: 1 kHz

• Multiple poloidal positions (5)

• Multiple radial locations (max 3)

• BUT, no pitch angle resolution

Also

• Detector composed of multiple thin metal foils separated by mica foils

• Ion energy determines deposition depth

• Ion current measured for each foil individually

• Current vs depth gives energy distribution (∆E~30–50%)

Moderate Energy Resolution (max 8 bins)

Fast Ion loss Detectors (1) Faraday Cups


Scintillator Probe

Location: Octant 4 lower limiter guide tube

Fast Ion Loss Detectors (2) Scintillator Probe

USA (PPPL, CSM), JOC


- energy range selection

- pitch-angle range selection

Particle energy is linked to

gyroradius of fast ions :

Observation of lost ions:

- particles hit surface of the scintillating material

- light emission allows - to use fast CCD and

PMT detectors- 20 kHz camera, 5 kHz P.M.

Ion selection is defined by slit-geometry and field

Entrance aperture: 1-µ Au foil stops

low energy ions

H, D < 150 keV; He < 250 keV

ZBmErT

/⊥∝

Scintillator probe provides 2D lost-ion images (pitch-angle & gyroradius)

Scintillator Probe (1) - Features


Scintillator Probe (2) – Main project activities


Scintillator Probe (3) – Data Visualisation


Neutral Particle Analyser (Radial) Neutral Particle Analyser (Radial)

DD00 and Tand T00 distributionsdistributions

Z = 0.28 m A

B

C

D

Low-energy NPA measures simultaneously the energy distribution function of

neutral H, D and T in the energy range 5 – 740 keV.

• D / T ratio measurements in the plasma core

• ICRH heating efficiency

NPA


R = 3.07 m

A

B

C

D

High-Energy NPA measures the energy distribution function of neutral H, D, T, 3He and 4He in the energy range 0.3 – 4 MeV.

Si-detectors now installed for better distinguishing D and α’s!

NPA

Neutral Particle Analyser (Vertical)Neutral Particle Analyser (Vertical)

Vertical LoS


How NPA worksHow NPA works

Neutralisation in plasmaNeutralisation in plasma

Ionisation by carbon foil Ionisation by carbon foil

(~30 nm)(~30 nm)

Acceleration (horizontal)Acceleration (horizontal)

MomentumMomentum--energy energy

separation (B, E)separation (B, E)

Detection (in 2D array of Detection (in 2D array of

CsI or Si)CsI or Si)

Data acquisitionData acquisition

+HV

B

EC foil

Atoms

CsI(Tl) scintillator+ PMT detectors

JET

E deflection is used to select the particle


Overview of recent NPA upgradeOverview of recent NPA upgrade

Detectors

UHV

Flange

Preamplifiers 16 pair

cable

thinthick

J P F

After

pulse

P P F

Chain1

J1T

CO

DA

S

1.5 GB


Raw Data from the NPA Si detectorsRaw Data from the NPA Si detectors

n only n+ions ions only

Vertical: Energy, Horizontal: Time through JET pulse (3 conditions)

Bottom 2 Plots are Power in the pulse (NBI & ICRH) and Neutron output


Summary: Current JET Fast Ion Diagnostics Systems

SystemsSystems JET DetectorJET Detector CapabilitiesCapabilities

Lost Ions:

Time-resolved charged

particle analysers

Faraday cupsMultifoils, 5 Poloidal angles

Fast Ion losses: fast

response, low E resn,>300/850 keV, H,D/He

Scintillator ProbeTG-Green, CCD & PM arrays

Confined Ions:

Gamma Emission

Profile Monitor

(2D-cameras)

Gamma Camera:CsI Scintillators

Fast Ion spatial

distributions via:

Gamma Emission Profiles & Tomography, EG 0.6-6 MeV

Confined Ions:

Gamma Spectrometers

Horizontal View: BGO

Vertical View:NaI, LaBr3, HpGe

Fast ion energy distribution

(NBI and ICRH heating)

By Gamma Emission Spectra>50/900/1700 keV for H,D/3He/4He

Fast Ion losses: vs E

range & pitch angle >300/850 keV, H,D/He

Horizontal* & Vertical

NPAs: C, ExB, CsI

Fluxes of neutrals by:Energy, Species

Neutral Particles:

Time-resolved neutral

particle analysers


The EndThe End

JET Neutron, Gamma & Particle DiagnosticsJET Neutron, Gamma & Particle Diagnostics

jet neutron, gamma & particle diagnostics · 2013-05-30 · jet neutron, gamma & particle...

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