NanoSIMS 50 & 50L Instrumentation - Intercovamex

NanoSIMS 50/ 50L
Secondary Ion Mass Spectrometer
for trace element and isotope analysis
at sub-micron resolution
INTRODUCTION TO THE INSTRUMENTATION
NanoSIMS 50

Key components
Duoplasmatron source: O -
Optical
microscope
NEG
Normal Electron
flood Gun (option)
Wien mass filter for the duo
Retractable Cesium source: Cs +
X-Y sample
stage motors
Motorized slits (option)
Magnetic sector mass analyzer
Ion pump
for intermediate
chamber
Ion pump + Ti sublimator
for Analysis chamber
Multi-collection:
5 EM plus 1-2 FC (NS50),
7 EM-FC (NS50L)
Geo Faraday
low noise FC
preamp option
Motorized
Exit slit option
Co-axial primary and secondary ion beams
Parallel detection of five (NS50) or seven (NS50L) ionic species
High transmission at High Mass Resolution
UHV technology, dry primary pump, turbomolecular pumps,
ion pumps and titanium getter
NanoSIMS 50

Sample introduction
Vacuum controller
Intermediate/ Analysis
Isolation Valve
Transfer Rod
Intermediate/ Analysis
Intermediate
chamber
Transfer Rod
Load-lock/ Intermediate
Load-lock
Heating lamp, turbo-pump
Load-lock/ Intermediate
Isolation Valve
Selection of sample
holder on Carrousel
(8 parking positions)
Standard 2-inch load-lock with turbo pumping, heating lamp for
sample degasing, mechanical transfer rod to the storage chamber.
8-position intermediate storage chamber with ion pumping,
transfer rod to the analysis chamber.
Vacuum automation with independant processor
NanoSIMS 50

Ultra fine feature
SIMS analysis requirements
1) FUNDAMENTAL LIMITATION: SIMS sensitivity gets poorer as lateral
resolution gets better (SIMS is destructive)
There are typically 1.25M atoms in a volume of 50 x 50 nm x 10 nm. With an ionisation of 0.005
and a transmission of 1, one can detect around 6000 atomic ions, meaning a detection limit of
roughly 0.1at. % level from a single pixel volume.
For comparaison, using a CAMECA IMS instrument with larger beam current over a larger area
(50 x 50 µm x 10 nm), one will sputter 1.25E12 atoms and be able to reach ppb level from the
whole area. This illustrates the compromise between lateral resolution and sensitivity,
exacerbated in a destructive technique (one can not only accumulate longer, as sample is
sputtered away).
2) HIGH LATERAL RESOLUTION together with HIGH BEAM DENSITY:
==> short working distance, normal incidence, high brightness ion sources
3) HIGH IONIZATION YIELD OF SPUTTERED PARTICLES (small and
limited volumes available, SIMS is destructive):
The use of reactive primary ions (Oxygen and Cesium) is mandatory in order to enhance atomic
secondary ions, in dynamic SIMS mode (sputtering of at least a few nm for trace element
analysis). Gallium gives 100-1000x less elemental signal in general.
No LMIS Gold or Bismuth as used on TOF-SIMS: enhancing molecular ion yield for static SIMS
mode is of no use for element or isotope analysis in dynamic SIMS.
4) HIGH TRANSMISSION MASS SPECTROMETER and PARALLEL
DETECTION
Small volumes available + perfect image or isotope registration ==> TOF or MAG. No
quadrupole (low transmission and monocollection).
High transmission together with high lateral resolution ==> Microprobe mode (ion microscope
mode not usable for sub-micron resolution: low transmission)
5) HIGH MASS RESOLUTION together with SMALL SPOT:
==> MAGNETIC SECTOR (no TOF analyzer: small spot OR high mass resolution , no
quadrupole analyzer: Low Mass Resolution)
6) REASONABLE ACQUISITION TIME:
==> MAGNETIC SECTOR (no TOF: much too low duty cycle & data rate:
200-1000 longer acquisition time for same element or isotope signal)
NanoSIMS 50

NanoSIMS 50 synopsis
Two reactive ion sources:
O - , Cs +
Normal, co-axial
primaries &
secondaries
Parallel detection
of five ionic i species
(NS50) or seven (NS50L)
NanoSIMS 50

Conventional and co-axial
probe forming systems
Any design of a SIMS instrument must accommodate two conflicting needs: the objective lens of the primary ion
column must be as close as possible to the sample in order to optimize its optical properties, leading to small
and intense ion beam.
On the other hand, secondary ions are emitted in a half-space, with a large energy spectrum (~ 0-200eV). In
order to collect as a large fraction of these ions as possible, the extraction optics should also be placed as close
as possible to the sample. As the extraction and objective optics have their own physical size, a compromize
must be found leading to large sample/optics distances. The NanoSIMS design has escaped from this dilemna
by switching to a totally new co-linear optics capable of simultaneously focusing the primary ions with high
quality, and collecting most of the secondary ions.
Primary beam
Secondary beam
Primary beam
Secondary beam
Probe
forming
optics
Extraction
optics
Deflection
plates
Extraction
and probe
forming
optics
Sample
Conventional
SIMS
Sample
Co-axial
NanoSIMS
Advantages of co-axial configuration :
• Short working distance of the probe forming lens/ extraction
1) smaller spot size for a given beam current
2) higher collection efficiency and dramatical reduction of the broadening of the secondary ion beam
due to the initial angular and energy distribution.
This will favour transmission of the analyzer at high mass resolution.
• Minimization of shadowing effects for non flat surfaces; hole or trench bottom analysis capability
• Obtention of deep craters of small size
• Reduction of the beam and raster distorsion
Constraints due to co-axial configuration :
• Primary and secondary ions must be of opposite polarity and equal energy (Cs + / negative ions, O - / positive
ions). This excludes MCs + technique and the use of O2+ ions for electropositive elements.
• Oxygen flooding can not be used
NanoSIMS 50

Lateral resolution with cesium
The use of cesium primary ions is mandatory in SIMS for the analysis of electro-negative elements (H, C, O, N, F, Cl, P,
Ge, Se, As, Br, Te, I, Au…). It enhances the ionization yield (= sensitivity) by several orders of magnitude compared to
non-reactive primary species (Ar, Ga, Au, Bi…).
The NanoSIMS is equipped with the patented CAMECA Microbeam cesium ion source, guaranteeing the highest
brightness available among commercial cesium ion sources. The source brightness (in mA/sr/cm 2 ) measures the ion
current available within a given solid angle from a given source area. It is an invariant in optics: a perfect (= without
optical aberration) primary ion column could at maximum re-obtain this brightness in the final spot size. The high
brightness of the ion source, the short final objective working distance, its reduced aberration coefficients, and the
normal incidence guarantee the best performance available from a SIMS microprobe for electronegative secondary ion
microanalysis.
Beam spot size (= lateral resolution) is determined by extracting the 16%-84% intensity line-scan from a SIMS image of
a TiCN sample giving sharp grain boundaries without artifact. Condition: 16 keV Cs + , negative secondaries.
12
C 2
12
C 14 N
300nm
Field: 4 X 4 µm, 512X512 pixels, Acq time: 30min.
300nm
12
C 2
12
C 14 N
Measured lateral
resolution: 25nm
200nm
Field: 2.5 X 2.5 µm, 256X256 pixels, Acq time: 22min.
200nm
Conservative spot size specification (16-84%) for Cs + :
50nm/0.3pA, 100nm/2pA.
NanoSIMS 50
Sample by courtesy of LAM, Luxemburg

Lateral resolution with oxygen
The NanoSIMS is equipped with the high brightness CAMECA duoplasmatron ion source. Although it can
generate positive ions (0 2+ ), it is mainly used in the NanoSIMS to generate 0 - ions. Due to the opposite
polarity scheme, one can benefit from the strong ionization enhancement of electropositive elements with
oxygen implantation. Additionally, the use of primary negative ions offers the well-known advantage of much
lower sample charging problems compared with positive primary ions (the sample always tends to charge
positively due to the secondary electron eec emission).
sso The beam spot size is determined by extracting the 16%-84% intensity line-scan from a 27 Al + SIMS image
recorded here on a sample containing Al grains.
27Al +
100%
Intensity (A.U)
84%
16%
O - : 0.3pA,
16-84% < 170 nm
0.0 1.0
2.0
Distance (microns)
Field: 7.5 µm x 7.5 µm, 16-84% spot size: 170 nm, O-: 0.3pA
27Al +
100%
Intensity (A.U)
84%
16%
O - : 2pA,
16-84% < 340 nm
0%
0.0 1.0
2.0
Distance (microns)
Field: 10 µm x 10 µm, 16-84% spot size: 340 nm, O-: 2pA
Conservative spot size specification (16-84%) in O - :
200nm/0.3pA, 400nm/2pA.
NanoSIMS 50
O 2- current specs typically four time lower than O - .

Analyzer Transmission
versus Mass Resolution
MRP T (%)
3500 100
5910 68
6120 65
6770 56
7120 51
7390 45
7885 39.9
9470 29
9615 24.5
Without any slit, mass
resolution is 3500 and
transmission is taken as
100%. Other transmissions
are referred to this one.
Transmission
e transmission
relative Relative T
100
90
80
70
60
50
40
30
20
10
0
100% Other transmissions 2000 3000 4000 5000 6000 7000 8000 9000 10000
mass resolving power
Mass Revolving Power
Mass resolution is taken as M/dM = R/4 * L 10-90 , where R is trajectory radius
and L 10-90 is line width corresponding to 80 % of intensity
Optimized for lateral resolution and sensitivity, the NanoSIMS is a pure ion Microprobe (scanned
focused ion beam) and has no ion microscope mode (transport of a stigmatic, magnified mass
filtered ion image) as on the CAMECA IMS analyzers.
One of the characteristics of the NanoSIMS is to work in high mass resolution: by design, there is
no low mass resolution mode on the NanoSIMS, even when removing all apertures.
In addition, the analyzer transmission is maintained very high (see plot above), even en when
increasing the Mass Resolution. This is the result of:
- a very high, normal extraction field allowing a very early secondary ion focusing,
- a limited field of view together with a dynamic emittance matching,
- a careful transport and rectangular shaping of the secondary beam resulting in
the use of small slit compared to the magnet size, reducing aberrations,
- the correction of the second order mass spectrometer optical aberrations.
NanoSIMS 50

NanoSIMS 50 main options
NEG. Normal incidence Electron flood Gun for the analysis of strong electrical insulators in Cs + with negative
secondary ions, when gold coating method is not sufficient, at high beam current.
SED. Secondary Electron Detector. Works only in negative secondary polarity with cesium primary ions. Can
give nicely contrasted topographical images for illustration and sample visualization.
Full-MDA. Motor Driven Apertures. Automation of diaphragms, apertures and hexapole for an easier
operation, a better reproducibility and a higher throughput.
Z-motor. Automation of the sample stage Z-axis. Allows to re-adjust the sample Z position for sub-permil
isotopic ratio reproducibility in geochemistry, in automated or chain acquisition mode.
Geo-Faraday. Low-noise FC electrometer for geological applications in single FC-EMs mode.
Dual-Faraday. Special trolleys #1 & #2 derived from NS50L design, equipped with both E.M. and F.C.,
allowing FC-EM or FC-FC acquisition modes. Includes thermostated FC preamplifier chamber with
intercalibration. Keeps the standard FC attached to the the lower mass side of trolley #1.
NMR H/D. Additional NMR probe to ensure the best long term stability for hydrogen-deuterium measurements
(the B field is too low for the standard NMR probe to improve the stability compared to the standard Hall probe
regulation mode).
NanoSIMS 50
Note: all options are field-retrofittable

NanoSIMS 50L
The Multicollection analyzer of the NanoSIMS 50 can measure five masses with two key characteristics:
1) Mass Dispersion (M max /M min in a parallel acquisition)
= 13.2 (or 14.4 with LD option).
For ex, one can follow 12C on trolley #1 and get mass 12 x 13 =
156amu on the fixed detector #5 at large radius.
2) Due to the finite width of the detectors and their
angle relative to the focal plane, the minimum Mass
Interval between two adjacent detectors is Mmax/30.
Ex: 27, 28, 29, 30amu can be analyzed simultaneously but 57,
58, 59, 60amu require two acquisitions: 57 & 59 then 58 & 60.
8mm
NS50
The NanoSIMS 50L receives a larger Multicollection analyzer improving several specifications:
-with the introduction of exit cylindrical sectors, the Mass Separation between een adjacent detectors is Mmax/58.
- the magnet size is enlarged in order to reach a Mass Dispersion M max /M min = 21.
- seven masses can be measured in parallel (five on the NS50)
- in standard: one FC and seven EMs. In option, each trolley can be equipped with E.M. and FC.
M max /58
NS50L
M max /M min = 21
Side view of four trolleys of the
NS50L multicollection
7 masses in parallel (ex: all O and Si isotopes in parallel, or 50-52-53-54Cr + 51V +48Ti + 55Mn)
Up to 58Fe in multicollection and single mass separation (Ti, Cr, Mn, Fe isotopes accessible)
Seven Faraday Cup option.
NanoSIMS 50

NanoSIMS 50/50L
The NanoSIMS 50L mainly differs from the NS50 by its larger multicollection and associated larger turbo-pump. Some
other, minor differences: the Z-motor, optional on the NS50, is standard in the NS50L, and the LD large detector option
of the NS50 is not available on the NS50L.
The general size of the instrument is not changed dramatically as can be seen from photos below:
Standard NS50
NS50L
NanoSIMS 50
NS50L

Full-MDA option (NS50/50L),
Seven-Faraday (NS50L) and Dual Faraday (NS50)
1) Full-MDA: the NanoSIMS 50 and 50L can both be equipped or
retrofitted with the automation of D0 and D1 diaphragms, entrance, aperture
and energy slits, hexapole centering, and individual trolley exit slit exchange.
The benefits are an easier operation (important specially for multi-user
operation), a better reproducibility for high precision isotopic ratios (subpermil
level) and a higher throughput (faster tuning checks or pre-sputter at
high current followed by analysis at high resolution in a chain analysis, etc…).
Automated D0
primary diaphragm
Energy Slit
Entrance & Aperture
Slits
Z-axis of the sample
stage
D1 co-axial lens
diaphragm
Automated exit slit exchange
2) Seven-Faraday: each trolley of the NanoSIMS 50L is equipped simultaneously with one E.M and one F.C.
This allows to achieve deep sub-permil isotope ratio reproducibility using primary currents of a few nA. Each FC has
its own preamplifier inside the thermostated FC preamp. chamber. The EM/FC selection is done multicollection
opened at atmospheric pressure by mechanically sliding the detector behind the exit slit. There is no more FC
attached on the smaller radius side of the trolley #1.
FC
EM
Thermostated low-noise Seven FC
preamplifier chamber allowing
intercalibration of the FC signals.
Synoptic of NS50L Seven-Faraday option
NS50L detector trolley showing scanning
plates, exit slit mechanism, cylindrical
sector and detectors (EM and FC)
3) Dual-Faraday is a standard NanoSIMS 50 option. The two lowest radius trolleys #1 and #2 are equipped
simultaneously with one E.M and one F.C. Each FC has its own preamplifier inside the thermostated FC preamp.
chamber. The EM/FC selection is done multicollection opened at atmospheric pressure by mechanically sliding the
detector behind the exit slit. Note that contrary to the 7FC option of the NS50L, this option keeps the (third) FC
attached on the lower side of trolley #1 of the NS50.
NanoSIMS 50

NanoSIMS sample mounting 1/2
The standard NanoSIMS holder is 50mm in diameter. The front plate can be customized depending on the user needs. Sample
thickness can be up to 9mm. The sample surface must be flat. The Z movement of the sample stage can be used to keep
sample/extraction distance at 400µm +/- 50µm. Due to the small sample-lens distance, the sample must not degas too much in
order to avoid risks of arcing. Typical working condition is in the E-9/ E-10 torr range. We thus recommend to minimize, if any, the
embedding material volume. Gold coating of the sample is generally used in order to reduce sample charging problems.
Below is a schematic of a NanoSIMS sample holder with 10mm holes (different hole sizes are available), with parts giving an idea of
some possible mountings. For an easier viewing, the schematics are not at scale.
PARTS
SOME SAMPLE MOUNTINGS
0.1mm
Attention! If rectangular sample, check
its diagonal to be less than 10.4mm !
Ø9mm
Ø10.4mm
+0, -0.05
Gold
Part of the sample holder.
Material: ARCAP AP4
Ø10mm
+0, -0.1
Intermediate
variable
Ø10mm
+0, -0.1
ring.
Material: ARCAP AP4
Thin flat sample glued or fixed with non-degasing
(< 1E-9 Torr) conductive double-side sticky tape
4mm
film
Thicker flat sample glued or fixed with non-degasing
(< 1E-9 Torr) conductive, double-side sticky tape
Metallic cylinder.
Material: ARCAP AP4
Part #: 45620693
0.1mm
Ø10mm
+0, -0.1
4mm
Ø10mm
+0, -0.1
Four
Ø9mm
Thin plate with holes.
Four holes of diam. 3mm.
Material: Z2-CN18-10,
Part #: 45620694
Small particles pressed into a gold foil
Embedding ring.
Material: ARCAP AP4, Part #: 45620692
Attention! If rectangular sample to be embedded,
check its diagonal to be less than 9mm !
EOS
Amagnetic Spring
Small sample(s) analyzed through the
holes of the thin top « grid » or « plate »
EOP
03mm 0.3mm
Metal
cylinder
EOW
Sample
holder
same
potential
Coaxial optics showing the short working distance
Embedding in high vacuum resin or metal in metallic cylinder,
then polished (or not if it is flat) and gold coated if needed.
Ex: Korapox 439 epoxy (www.koemmerling-chemie.de),
Varian Torr Seal Low Vapor Pressure Resin (www.varianinc.com).
Also used: Wood metal (In-Bi alloy melting at 78°C)
NanoSIMS 50

NanoSIMS sample mounting 2/2
50mm/ 2-inch diameter
«WU-MPI» sample holder
with one 1-inch , two halfinch
and two 10mm holes.
Ref #: 45620643
25mm/ 1-inch diameter
«Standard» sample holder
with four 10mm holes.
Ref #: 45620641
50mm/ 2-inch diameter
«Biology» sample holder
with eight 10mm holes.
Ref #: 45620642
Shuttle
Ref # : 45621551
Reverse view of the « Biology» sample holder, unscrewed
from its shuttle. One can see the springs pushing the
sample cylinders in their hole against their lips.
It is possible to simultaneously load two shuttles on the
NanoSIMS sample stage : two 1-inch sample holders, or
one 1-inch and one 2-inch sample holder. Note that the
second 1-inch sample holder can be brought in SIMS
position but not in the optical microscope position. It is
generally used to store standard samples.
The NanoSIMS is delivered with eight shuttles and eight
sample holders: one “standard” and seven to be chosen
within the different models available (not all displayed in
this page, ask for a complete list).
Ex. of wrong mounting ! Must be
remounted with front reference.
Thin samples (ex: biological sections)
must be deposited on the POLISHED
side of the metallic cylinder !
Biological thin cross-section
deposited on 7.3x7.3mm silicon
square (diagonal=10 10.3mm).
Sample under 4-
hole thin plate
Embedded
sample
10mm diam.
embedding ring
Ref #: 45620692
10mm metallic cylinder
Ref #: 45620693
4-hole thin plate
Ref #: 45620694
Embedded
sample
Finger contacting the front
electrode of the objective lens.
NanoSIMS 50

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NanoSIMS 50