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Hydrogen-rich solid thin layersHydrogen-rich solid thin layers
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
A. Stolarz1, G. Sibbens2, A. Dean2, M. Józwik3, Y. Aregbe2
1 Heavy Ion Laboratory, University of Warsaw, Poland2 Institute for Reference Materials and Measurements, Geel, Belgium
3 Institute of Micromechanics and Photonics, Warsaw University of Technology, Warsaw, Poland
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
- as proton radiator at a recoil proton telescope (RPT) that are used for neutron flux measurements
- for determination of the cross section ratio of 235U(n,f) / H (n,n) reactions
octoconasol: C28H58O
polyethylene: C2H2
tristearin: C57H110O6
what for?
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
what was required?
thickness range 0.05 – 0.5 mg/cm2 (0.58 – 5.8 µm)
homomogeneity
stability over long period (special concern: humidity)
and
for RPT well defined geometry so it should be on a ridged backing
for cross-section ratio micro homogeneity
vacuum evaporation
melting point: 68 – 73 ºC (but could be as low as 55 ºC)
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Tristearin deposit on 2 mm Si wafer, depo rate 5-6 Å/s.
80xTa boat with hollow ~2.5 cm
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
0.5-1.5 Å/s
rate
20-35 Å/s
35-100 Å/s
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Si: 50 µg/cm2; 2.2 - 2.5 Å/s
quartz
Ta: 50 µg/cm2; 2.5 – 3 Å/sTa disc 0.1 mm thick
500 µg/cm2; 30-100 Å/s
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Ta: 50 µg/cm2; 2.5 – 3 Å/s
Ta: 100 µg/cm2; 5.5 - 6 Å/s
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
trist - ~50 µg/cm2
polyimide foil - ~30 µg/cm2
rate: 1.3 -1.5 Å/s
(100x)
from AFM focusing microscope
500x
tris on PI
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Trist ~40 µg/cm2
deposited on polyimide foil ~ 30 µg/cm2 backed by 2.5 mm Cu rate: 1.5-1.7 Å/s (100x)
tris on PI+Cu
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010 tris on PI+Cu
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
depo quality strongly depends on the heat trasfer
q = k A dt/s
k -thermal conductivity coeff.
dt -temp. grandient across the material
A -area
s -thickness
q ≈ k/s
s Si = 2 mm k = 150 W/(m×K)
s Ta = 0.1 mm k = 57 W/(m×K)
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
thickness determination:- by quartz balance: needed acoustic impedance
value for tristearin estimated as 1.15 x105 g cm-2 s-1, based on weighing the known area (approach via values found for fat and paraffin)
- mass/area: samples prepared on 5 µm aluminium foil and on Ta 0.1 mm thick discs
- AFM and optical profilometry
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
thickness and its homogeneity
?0.600.56 - 7Ta 3
?1.231.15.5Ta 2
?0.640.52.3 - 2.7Ta 1
9582
92.4 %77 %
1.040.86
0.69-0.720.53-0.62
-1.121.12
25 – 302 - 7
Si 161
89 -9083
91%73.2 %
0.500.40
0.32-0.370.25-0.3
-0.550.55
25 – 302.5 - 3.0
Si 49
83 %4.563.1-5.5 30 -110Si 4747103 %0.380.19-0.37 0.5-0.7Si 44
homogenity
%
% of quartz indic.
OP corrected ntris=1.47
OP [ µm ]
weighing[µm]
quartz [µm]
rate [Å/s]
sample
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Soft, low melting point deposits as tristearin should be prepared onbackings assuring good heat transfer as grain size, layer homogeneity is dependent on heat dissipation from backing.
Taking into account demand of ‘rigid’ geometry for proton telescopes may be thin Si wafer (instead of Ta) should be taken into consideration as backing as Si has much better heat conductivity.
Hydrogen content in the samples as for the moment is defined by weighing and molecular stoichiometry.
UNIVERSITY OF WARSAWUNIVERSITY OF WARSAW Heavy Ion LaboratoryHeavy Ion Laboratory
25th INTDS Conference, Vancouver, Canada 2010
Acknowledgement:
Work was partly supported by FP6 EFNUDAT project.
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