D retention in bulk Be and D co-deposited in Be layers
studied by 3 different thermal desorption techniques
and their modelling by CRDS

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19 th June 2019 I Miro Zlobinski*, D. Matveev, M. Eichler, T. Dittmar, G. De Temmerman, C. Porosnicu,
B. Unterberg, G. Sergienko, S. Brezinsek, D. Nicolai, A. Terra, M. Rasinski, B. Spilker, M. Freisinger, S. Möller,
Ch. Linsmeier, C. P. Lungu, P. Dinca

Jülich, Germany

St Paul Lez Durance Cedex, France

Bucharest, Romania

This work has been carried out within the framework of the EUROfusion Consortium and has received funding fromthe Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053.
The views and opinions expressed herein do not necessarily reflect those of the European Commission or of the ITER Organization.
Work performed under EUROfusion WP PFC and ITER SC IO/16/RFQ/13369/IDS.

Outline• Be/D layer production on W (HiPIMS)----------------------------------------------------------------------------------------------------------------------- - - - - - • new Analysis device (FREDIS)• LID (Laser-Induced Desorption) in FREDIS• TDS in FREDIS• Modelling__________________________________________________________________________________________• Bulk Be: D implantation & TDS (ARTOSS)• Modelling• Summary & Outlook____________________________________________________• Good news: GO for new Hot Cells in Jülich
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Be Layer Deposition in Bucharest
small samples (W):
5 mm x 5 mm
x 5 mmbig samples (W):
36 mm x 36 mm
x 5 mmMethod: High Power Impulse Magnetron Sputtering (HiPIMS)
in D atmosphere by INFLPR• pulsed magnetron plasma: several MW/m2 during 3 µs
• Be layer thickness: 1 µm and 10 µm, new: 20 µm

witness samples (Si)element
Be (EDX)
D (NRA)H (LID)
O (EDX)C (EDX)
N (EDX)

small
sample
at%
70-72
25-27
1.1
1.0
1.80.4

bigsample
at%
67-69
28-30
1.1
1.9
0.60.4• D content: 1-30 at% (measured by NRA)
• substrate: 5 mm polished W (IGP) by Plansee with grains
elongated perpendicular to the surface• <3E-6 hPa base pressure, 2E-2 hPa after gas inlet• sample temperature ≈ 340 K, RT
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Microstructure of co-deposited Be/D layer

HiPIMS layers

1.2-1.8 at% D
10 µm

tokamak layer

27-30 at% D
1 µm

layer from JET

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Analysis Device in Jülich: FREDIS(Fuel Retention Diagnostic Setup)
LID
TDS
fibre-optic cable from laser

glove boxes
for safe
handlingof Be

camerax/y/zstagepyrometerhi-res.
QMS(MKS)
0-6 u/etritium trap
(under construction)
overview
QMS(Pfeiffer)
0-100 u/e
filterdistancemeasurement
laser beamgas washingbottles

CuO
catalyst

filterlaser head

GV

FREDIS features:
beryllium compatible
soon: tritium compatible
located in radiation
controlled area

air lock(open)
TPTDS
sampleTPTDS oven(open)

tritium
detector

LID
sampleexhaustTP

Ref: M. Zlobinski et al.,Fus. Eng. Des. (2019) in press,
doi:10.1016/j.fusengdes.2019.02.035

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3.0

laser pulse duration
2.5 1 ms 2.5 ms 5 ms 10 ms 20 ms

120%
100%

2.080%

1.5 beryllium melting temperature60%

1.0

40%

0.5

20%0.0500

700

900

1100

1300

1500

1700

1900

2100

2300

0%
2500

desorbed fraction

desorbed D / 1022/m²

LID desorption efficiency on 10 µm Be layer with 1.6 at% D

below Be melting:up to 50% D desorption
with a single laser pulse
with Be melting:>99% D desorption
with a single laser pulse

max. temperature (pyrometer) / K
NRA in laser spot centre
shows that up to 99%of D is desorbed

for 1 µm Be layer with 30 at% D:>99% D desorbed
by one laser pulse
without meltingµNRA 3He++ (4.15 MeV)O-9page 6/23

1E22
1E212

12 K/min
24 K/min (after LID)
24 K/min

2

1E20
1E194

1E184

1E17
1E16400500

600

700

temperature / K

800

900vs10 µm, 1 at.% D
desorption flux (mass 4) / D/s/m2

desorption flux (mass 4) / D/s/m2

TDS spectra: 1 µm, 25-30 at.% D

1E2003 K/min
12 K/min

1E19

1E18

1E17

1E16400

600

800

1000

1200

temperature / K

high temperature TDS peak could be thereason for the lower LID efficiency
below melting
ultra-sharp TDS jump: instantaneous (within 0.4 s), by factor ~30
only in thick layers (fast heating of 10 µm, all 20 µm)
reason: layer detachment ???

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TDS spectra: at least 6 TDS peaks observed
Be/D layer on W

narrow Low Temperature (LT) peak:consists of 2-3 peaks
small peak 4
broad High Temperature (HT) peaks:
often several peaks

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TDS spectra: general observations
Be/D layer on Wrun

14 at% Dµm

1 at% D
1 µm  10 µm

4 at% D

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Coupled Reaction-Diffusion Systems (CRDS)The code is similar to TMAP-7, TESSIM, MIMPS and others diffusion-trapping
codes
Modes of operation:

Basic equations:(1) Equivalent to TMAP-7 with either
immediate desorption (𝑐 𝑥=0 = 0)or with molecular desorption flux
Γ = 𝜅 𝑐 𝑥=0 2(2) Accounting for actual surface coveragewith saturation effects: 0 ≤ 𝜎 ≤ 𝜎𝑚𝑎𝑥

Further features:- multiple-occupancy of traps- trap mobility[D. Matveev]

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Modelling of D release from Be/D co-deposited layers
Sharp low temperature releaseHigh temperature releases(t)=(1-erf[(t-t0) ⁄ t]) ⁄ 2 switch off re-trapping (e.g. trap annealing)collective de-trapping, e.g. release from gas bubbles by their openingor percolation through a porous network at threshold temperature t0[D. Matveev]

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Ramp & Hold experiment: nature of low-temperature peaks

release is not governed by de-trapping;permanent supply of hydrogen [Baldwin et. al: “hydrides”]
alternatively: strongly surface limited releaseO-9

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Material Change• INFLPR/FREDIS: sputtered Be layers in D gas atmosphere  co-deposited D layers on W
Material change: Still Be but …
• ARTOSS: Bulk Be (Be SC, Be polycrystal) with implanted D

ARTOSS (name could mean… “All Relevant Techniques Of Surface Science”)• Mass & energy separated ion source 0.1-20 kV• Sputter cleaning ion source, 1-5 kV• Thermal atomic H source• Electron beam evaporator• Accelerator beam: NRA, RBS, …
• QMS mass spectrometer for TPD, TDS• TDS heating by e- beam
• XPS: X-ray source and electrostatic analyser• Base pressure < 5 · 1011 mbar

• Beryllium compatible[T. Dittmar, M. Eichler]

Beryllium single crystal fluence scan

Mass 4 (D2)

implantation: D3+ (1 keV/D), 1E18 /m2/s
TDS heating rate: 0.01 K/s• High-temperature peak shifting• Multitrapping in single vacancies?
• Depth effect?

• Low-temperature peak splitting• LT-peak consists of min. 2 sharp peaks• Cannot be explained with Arrhenius release• Pre-LT-Peak• Release of solute Deuterium[T. Dittmar, M. Eichler]

Ref: M. Eichler,
Nuc. Mat. En. 19 (2019) 440–444,
doi:/10.1016/j.nme.2019.03.018

Beryllium polycrystal fluence scan
Mass 4 (D2)

implantation: D3+ (1 keV/D), 1E18 /m2/s
TDS heating rate: 0.01 K/s• High-temperature peak shifting• Similar behaviour as single crystal• Low-temperature peak splitting• LT-peak consists of min. 3 sharp peaks(0.43 eV, 0.67 eV and 0.82 eV)• Forms single dominant peak at high fluence• Pre-LT-Peak• Visible as „shoulder“

Compare [Baldwin et. al: “only 1 LT peak”][T. Dittmar, M. Eichler]

Ref: M. Eichler,
Nuc. Mat. En. 19 (2019) 440–444,
doi:/10.1016/j.nme.2019.03.018

Modelling of D retention in crystalline Be
Modelling of new ARTOSS data (ongoing)
Defect evolution during implantation is taking into account directly in simulations
Slow down of defect creation (net) and defect saturation are reproduced

CRDS[D. Matveev]

Experimental dataARTOSS

Ref: M. Eichler,
Nuc. Mat. En. 19 (2019) 440–444,
doi:/10.1016/j.nme.2019.03.018

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Modelling of D retention in crystalline Be
Qualitative agreement- high temperature peak shift (effect of re-trapping) and shoulder (multiple-trapping)- low temperature peak threshold (surface occupation after bulk saturation)

CRDS[D. Matveev]

Experimental data: M. Reinelt, NJP 2009

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Reason for LT peak splitting in ARTOSS

Hypothesis:

different adsorption surfaces for De.g. blisters

Be polycrystal after implantation of D3+ at
2 keV/D. Blisters are formed on the surface,which are partially cracked open on
the top while others are peeled off or in theprocess of flaking[T. Dittmar, M. Eichler]SummaryLID (Laser-Induced Desorption within ms):
• for 1 µm HiPIMS Be/D layer with 30 at% D: complete D desorption (i.e. >99%) possible by a single laser pulse
without melting• for 10 µm HiPIMS Be/D layer with 1.6 at% D: up to 50% desorption until melting,nearly complete D desorption (ca. 99%) possible with melting
key for understanding probably in TDS spectra
TDS (slow Thermal Desorption Spectrometry):• Be: 1st time observation of up to 3 LT subpeaks• LT peak contribution increases with D concentration/implantation flux
• LT peak very narrow  cannot be simulated by standard diffusion-trapping modelneed to introduce: collective de-trapping, switch off re-trapping, …
• HT peak (multipeak) widens with D layer thickness/D depth• qualitatively similar TDS spectra for bulk Be (single crystal, polycrystal) and sputtered Be layers• ultra-sharp peak  ???

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Outlook• Is the laser desorption temperature determined or diffusion dominated?
 analysis of increasing heating by LID on same position• modelling of TDS and LID ongoing to transfer the results• dominant effects• sensitivity of desorption on binding energy, diffusion activation energy, …
• new TDS setup: i-TDS (inductive TDS): ca. 2000 K in ca. 1 min; between LID and classical TDS• LID and TDS of our 1st JET samples with thick Be co-deposited layers in FREDIS• tokamak layers behaviour compared to HiPIMS layers (are they reactor relevant?)• differences between T and D desorption?
• future application and modelling of LID in JET and ITER

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Jülich-HML (High temperature Material Laboratory)

few weeks ago:
funding granted for buildingof new hot cellsfor:• linear plasma device:
JULE-PSI• high heat flux test device:
JUDITH-3• analysis labs, …
to handle activated material
and beryllium
Thanks for your attention
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