current needs and developments in sanjeev varshney x-ray ... · 26.03.2015 · s. varshney, r....

© ITER-India, IPR (India)© ITER-India IPR (India)

Current needs and developments in X-Ray Crystal Spectroscopy for ITER

Sanjeev VarshneyITER-India, IPR, Gandhinagar (Gujrat)

ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015 © ITER-India, IPR (India)

The IO/DA Team

ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015 2

Sanjeev VarshneySapna MishraSiddharth KumarSubhash PuthenveetilShivakant JhaVinay Kumar

Robin BarnsleyGunter Bertschinger (FZ, Germany)Martin O’ Mullane (JET, UK)Philippe BernascolleMichael Walsh,and many more IO/DA contributors

Domestic Agency

© ITER-India, IPR (India)

Introduction ITER measurement requirementsOverview of ITER XRCS systems

- XRCS-Survey spectrometer - XRCS-Edge spectrometer

Summary

Outline

3ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015 © ITER-India, IPR (India)

Introduction

4

The objectives of X-Ray Crystal Spectroscopy onITER are to,

Monitor plasma impurities in 0.1 - 10 nm range forthe Machine protection and Basic control

Measure vertical profiles of important plasmaparameters for Advance control and Physics study.

ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015


The XRCS Package

5

ITER-India has signed procurement arrangements to deliver ‘two’ X-ray Crystal Spectrometers to ITER:

1) XRCS-Edge “imaging10% of the outer plasma”

- Ion temperature profile- Plasma rotation profile

2) XRCS-Survey “core plasma emission in broad band”

- Impurity identification- Concentration, in-flux

UP-09

EP-11

ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015 © ITER-India, IPR (India)© ITER-India, IPR (India)

ITER Parameters

66ICTP – IAEA Workshop on Plasma Spectroscopy, 26th March 2015


Functional requirements

7

MEASUREMENT PARAMETER CONDITION RANGE orCOVERAGE RESOLUTION ACCURACY

10. Plasma Rotation Profile

VTOR 1-200 km/s 10 ms a/30 30 %VPOL r/a > 0.9 2-5-50 km/s 10 ms a/100 10 %

12. Impurity Species Monitoring

Be, C rel. conc. 1x10-4-5x10-2 10 ms Integral 10 % (rel.)Be, C influx 4x1016-2x1019 /s 10 ms Integral 10 % (rel.)Cu rel. conc. 1x10-5-5x10-3 10 ms Integral 10 % (rel.)Cu influx 4x1015-2x1018 /s 10 ms Integral 10 % (rel.)W rel. conc. 1x10-6-5x10-4 10 ms Integral 10 % (rel.)W influx 4x1014-2x1017 /s 10 ms Integral 10 % (rel.)Extrinsic (Ne, Ar, Kr) rel. conc. 1x10-4-2x10-2 10 ms Integral 10 % (rel.)

Extrinsic (Ne, Ar, Kr) influx 4x1016-8x1018 /s 10 ms Integral 10 % (rel.)

28. Ion Temperature Profile

Core Ti r/a < 0.85 0.5 – 40 keV 100 ms a/10 10 %

Edge Ti r/a > 0.9 0.5 - 10 keV 100 ms 20 mm 10 %

32. Impurity Density Profile

Fractional content, Z<=10

r/a < 0.85 0.5 - 20 % 100 ms a/10 20 %r/a > 0.85 0.5 - 20 % 100 ms 50 mm 20 %

Fractional content, Z>10

r/a < 0.85 0.01 - 0.3 % 100 ms a/10 20 %r/a > 0.85 0.01 - 0.3 % 100 ms 50 mm 20 %


Impurity Line Doppler effects

8

High resolution imaging enables Doppler broadening and Line shiftsfrom the region of interest in plasma



Optical Layout for High Resolution

9

Crystal(spherical)

window

Sagital focus (ideal),plasma to crytal~ 7.5 m

Ref ΘB~480

crystal to LOS ~1.0 meter

Focus in the plasma for Bragg angle ~48o but for greater angles the sagittal focus is between the meridional focus and the plasma, and the rays will be diverging

Width in plasma depends on crystal height and Bragg angle

Concept tested on many tokamaks: ALCATOR, TEXTOR, KSTAR etc.


XRCS-Edge spectrometer

10

Design option with ‘three’ crystals: - shutters to select the appropriate lines - no high precision moving parts !

Three crystals for covering a range of plasma parameters:

540 ArXVII Kα (3.1219) Quartz 11-20550 ArXVIII Lyα (3.3206) Quartz 10-1253.60 FeXXV Kα (6.6685) Ge 422

(twice the energy of Ar XVIII Lyα)

Crystals are stacked one above the other

Simultaneous recording of H-like Ar and He-like Fe with energy discriminating advance detector under development



XRCS-Edge spectrometer


N- Flux with & without Shielding

12

Without shield in interspace With B4C shield in interspace

4.4E7 n/cm2/s 2.9E5 n/cm2/s

Relative error Relative error

Total n-flux (n/cm2/s) Total n-flux (n/cm2/s)

2.1E6 n/cm2/s 5.14E5 n/cm2/s



Thermal analysis with shield around


Estimation of Temperature profile on the sight tube of Edge spectrometer during Port Plug baking


Line-of-sight Signals

14

Results of ADAS and SANCO modeling:

W 40+ to 50+ relevant for the outer plasma

Chord integral profiles, Ar, Fe, W

Main W lines are around 4 – 6 Å

LOS intensity for 1% concentration



Performance simulation

15

For rotation measurements at time resolution 10 ms about 106 count/s are needed,For temperature measurements, in 100 ms about 100,000 counts/s are sufficient

The measurement requirements are met below 3.5 m for rotation and below 3.55 m for ion temperature.


Impurity Survey

16

The Primary role of X-ray Survey system is to monitor, in real time, the impurity content in the ITER plasmas.

Elements which may be abundant in the ITER plasma are:

Wall materials: Be (FW), W (Divertor)Fusion product: HeStructural materials: Cr, Fe, Ni,…Other in-vessel materials: Li, O, Mg, Al, Si, Ca, Zr, Mo, Rh,…Seeded impurities: N (for ELMs control)

Ne, Ar (for Radiative Divertor)

In the worst case, most or all of these species could be abundant in the ITER plasmas and radiate simultaneously (tens of MW).



XRCS-Survey spectrometer

17

Vacuum piping

Shielding

S. Varshney, R. Barnsley et al., Rev. Sci. Instrum. 83 (2012)

Integrated in EPP-11


Optical layout for Survey


slit

crystal

detector

O

u ≈ 10 m

hx = 10 cm

ws ≤ 1 cm, Hs ≤ 10 cm

Rx ≈ 20 cm

450

detector

1 2 3

λ1λ2λ3

nλ = 2d.sin(θBragg)

• Crystals are curved in 2-D (but not focusing)


Shadow-XOP Ray-tracing

19

Perpendicular bending of the crystal produces a vertical focusing of the slit image:

2 Pilatus detectors end-to-end (16 cm x 3.5 cm) receives at least 3 spectral channels

Line width is ~ 50 μm, equivalent to spectral resolution > 1:1000Typical x-ray detector pixels are 50 – 175 μm

0.36

15.0Silicon [111] crystal at central Bragg angle ~ 450

resolving lines of 2.8 ±0.7 keV

Rx [cm] 25.0

Ry [cm] 23.2


Crystals, Sensitivity and Resolution

20

Ch # Crystal hkl 2d (A)

Measurement range

(A)

Ch-1 Ge 422 2.31 0.98 – 2.09

Ch-2 Ge 220 4.0 1.60 – 3.63

Ch-3 Ge 111 6.532 3.28 – 5.92

Ch-4 ADP 101 10.64 5.32 – 9.99

Ch-5 TAP 001 25.763 10.89 – 23.35

Ch-6a MLM 44.0 18.59 – 39.88

Ch-6b MLM 110.0 46.49 – 99.69

• All crystals lower and upper cut-offs at the allowed Bragg angles 25–65 deg.

• Overlapping sensitivity coverage between channels

• RP: linear summation (solid) and quadratic summation (dashed)



Impurity Spectra

CDAMOP-2015, Delhi University 21

ADAS and SANCO impurity transport modeling (central chord) for H-mode plasmas̶ database of ~ 5000 spectral lines from

potential impurities in plasmas̶ H- and He-like lines in 1 – 100 Å


Predicted Performance

22

Low-z

Mid-z

High-z

• Survey signal analysis based onmodelling data of potentialimpurity lines in H-mode ITERreference scenario

the measurement requirementsare largely satisfied



MCNP neutronics analysis

23

MCNP neutronics analysis (Improved)

SS + B4C (Diameter ~ 35 cm) (50% + 50% )Homogeneous

Shut Down Dose Rate (SDDR in μSv/Hr) calculated at 1 m from closure plate in the PP interspace found low but still higher thenits allocated value

15 μSv/hr

17 μSv/hr11 μSv/hr

1.5 μSv/hr0.5 μSv/hr

Neutron shield


In ITER, intrinsic or extrinsic impurity emissions to perform HR and Survey crystal spectroscopy

(No problem of light reflections!)

Detailed design, analysis, and integration with port-plugs ongoing for both XRCS-Survey and XRCS-Edge systems Predicted performances have shown design compliance to the measurement requirements

OutlookX-ray lab sources, components development for prototype R&D, also for environmental testing

Summary



Current schedule


Thanks For Your Attention !

CDAMOP-2015, Delhi University 26

Steady State Superconducting Tokamak at IPR, Gandhinagar

current needs and developments in sanjeev varshney x-ray ... · 26.03.2015 · s. varshney, r....

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