Specac Gateway ATR User manual

Gateway™ ATR
6 Reflection Horizontal
ATR Accessory Kit
User Manual
2I-11165-5

Gateway™ ATR
6 Reflection Horizontal
ATR Accessory Kit
User Manual
2I-11165-5

User Manual
2
Gateway™ ATR Accessory Kit P/N GS11165
GATEWAY™ 6 REFLECTION HORIZONTAL ATR ACCESSORY KIT
USER MANUAL
1. INTRODUCTION .................................................................................4
2. SAFETY CONSIDERATIONS ................................................................6
3. CHECKLIST AND CONTENTS...............................................................7
4. PREPARING THE GATEWAY™ATR ACCESSORY ................................9
THE CLAMP ASSEMBLY (GS11171) ..................................................9
FIXING THE CLAMP ASSEMBLY TO THE OPTICAL UNIT .......................10
FITTING THE TROUGH OR FLAT TOP PLATE ASSEMBLY .....................13
TROUGH (3) AND FLAT (4) GATEWAY™ATR TOP PLATE .................14
THE TROUGH TOP PLATE ASSEMBLY...............................................14
CRYSTAL REMOVAL FROM THE TROUGH TOP PLATE ASSEMBLY........16
CHANGING THE ISOLAST GASKET OF THE TROUGH TOP PLATE .........17
RE-ASSEMBLY OF THE TROUGH TOP PLATE ASSEMBLY ....................18
THE FLAT TOP PLATE ASSEMBLY.....................................................21
THE PTFE PAD..............................................................................22
5. INSTALLATION OF THE GATEWAY™ATR ACCESSORY USING THE
BENCHMARK™BASEPLATE.............................................................23
6. ALIGNMENT OF THE GATEWAY™ATR ACCESSORY..........................24
FRONT COVER PLATE REMOVAL .....................................................25
ALIGNMENT PROCEDURE ................................................................26
7. FEATURES ON THE GATEWAY™OPTICAL UNIT.................................29
PURGING THE OPTICAL UNIT...........................................................29
FITTING THE PURGE BELLOWS (GS10707)......................................30
FITTING A POLARIZER .....................................................................32
8. SAMPLING USING THE GATEWAY™ATR ACCESSORY......................33
IMPORTANT NOTE FOR USAGE ........................................................33
PREPARING THE GATEWAY™ATR FOR ANALYSIS ...........................34
SPECTRAL COLLECTION USING THE GATEWAY™ACCESSORY..........35
COLLECTING A BACKGROUND SPECTRUM........................................35
COLLECTING ATR SPECTRA OF POWDER SAMPLES .........................35

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COLLECTING ATR SPECTRA OF FLAT SOLID SAMPLES.....................37
COLLECTING ATR SPECTRA OF LIQUIDS AND PASTE SAMPLES.........38
NOTES ON CLEANING .....................................................................40
DATASHEET FOR ZINC SELENIDE.....................................................42
DATASHEET FOR GERMANIUM.........................................................43
DATASHEET FOR SILICON................................................................44
9. GATEWAY™ATR ACCESSORY "BUBBLE NUMBERS"PART
IDENTIFICATION LIST.......................................................................45
10.GATEWAY™ATR ACCESSORIES PARTS LIST ................................46
11.GATEWAY™ATR TECHNICAL SPECIFICATION................................47
12. GATEWAY™ATR SERIAL NUMBERS .............................................48
© April 2016 Specac Ltd. All rights reserved.
Brilliant Spectroscopy is a trademark of Specac Ltd.
Other product names mentioned herein may be trademarks
of their respective owners.

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1. Introduction
Thank you for purchasing a Specac Product.
The Gateway™ ATR Accessory Kit P/N GS11165 is a 6 reflection
horizontal ATR system consisting of an optical unit (P/N GS11170), a
trough top plate assembly with a 45° angle zinc selenide (ZnSe) crystal
(P/N GS11166), a flat top plate assembly with a 45° angle ZnSe crystal
(P/N GS11133) and a clamp assembly (P/N GS11171). The trough top
plate is to be used on the optical unit for the analysis of liquids and
pastes and the flat top plate and clamp assembly are used on the
optical unit for the analysis of solids and powders. The trough top plate
assembly design allows for the easy removal and change of the ATR
crystal from ZnSe to germanium (Ge) or silicon (Si) crystal options.
The ATR ZnSe crystal is bonded into the flat top plate assembly using
an epoxy resin and is not removable, so for any of the crystal options
of a flat top plate assembly it is supplied as a complete assembly from
Specac.
The Gateway™ ATR Accessory is simple to install and operate within
a wide range of FTIR spectrometer systems via use of the Specac
Benchmark™ baseplate mounting assembly. Different Benchmark™
baseplates are available for specific fit into a particular make and
model of spectrometer system. The Gateway ™ optical unit attaches to
the Benchmark ™ baseplate by a single thumbscrew fixing for correct
optical beam passage and positioning of the Accessory when installed
into the sample compartment of the spectrometer system.
The Gateway™ ATR Accessory offers a relatively high optical light
throughput as the result of its unique optical design and the optical unit
offers the capability for fitting and use of a polarizer, if required, for
specific ATR studies. There is a wide range of interchangeable trough
type top plates available that can be used on the optical unit providing
for further sampling versatility. These static and flow through and
trough top plates allow for different temperatures (up to 200°C for the
electrically heated top plate), to be applied for liquid sample
measurements and the design of these top plates incorporates
removable crystals for ease of cleaning and simple replacement. All
top plates are fitted as standard with a 6 reflection ZnSe ATR crystal

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with a 45° angle of incidence. The Ge and Si crystal options are
available on request for use in these top plates. The ZnSe and Ge
crystals have an antireflection coating on their angled faces to help
improve the light energy throughput for these high refractive index
crystal materials (2.4 and 4.0 respectively).
The range of Gateway ATR top plates that can be used on the optical
unit are:-
P/N GS11133 Gateway™ ATR Flat top plate with 45° ZnSe crystal.
P/N GS11134 Gateway™ ATR Flat top plate with 45° Si crystal.
P/N GS11135 Gateway™ ATR Flat top plate with 45° Ge crystal.
P/N GS11166 Gateway™ ATR Trough top plate with 45° ZnSe crystal.
P/N GS11116 Gateway™ ATR Flow Through top plate (550um
volume) with 45° ZnSe crystal.
P/N GS11118 Gateway™ ATR Thermostabilised Flow Through top
plate (550um volume) with 45° ZnSe crystal.
P/N GS11139 Gateway™ ATR Water Heated Trough top plate with
45° ZnSe crystal.
P/N GS11155 Gateway™ ATR Electrically Heated Trough top plate
with 45° ZnSe crystal.
The Gateway™ ATR accessory can be configured for the analysis of
all types of samples (for example: solids, films, pastes, liquids, static or
flow conditions and heating applications up to 200°C) over a wide
spectroscopic range of frequencies using the different top plates and
crystal options. As supplied, the Gateway™ ATR Accessory has been
factory aligned and will only need minor adjustment after installation for
optimization of light throughput and performance in your spectrometer.
Fig 1. The Gateway™ 6 Reflection ATR Accessory Kit

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2. Safety Considerations
With use of any spectroscopic accessory that involves the study of a
wide range of chemical samples, the associated risk in handling may
mostly be attributed to the specific sample type to be handled itself. As
far as it possible you should follow a procedure for safe handling and
containment of the type of sample to be used.
With respect to safety of use specifically to the Gateway™ ATR
Accessory, this uses different crystal materials for the ATR crystal
Trough, Flat and Flow Through Top Plate assemblies where a sample
is bought into contact for analytical spectroscopic study. As standard,
Zinc Selenide (ZnSe), germanium (Ge) and Silicon (Si) are the three
crystal materials of choice that can be used.
Caution: Out of these three different crystal types, ZnSe is
the most potentially hazardous material with respect to
toxicity risk in use and handling.
Both Ge and Si crystal materials can be considered relatively safe to
use, although Ge may be harmful to the body if it is ingested in
significant quantity. The general rule when working with any crystal
material (and sample) is to always wear gloves and safety gear (e.g.
safety spectacles) when handling to obviate the risk of contact with the
skin.
Provided with each ATR crystal version of top plate assembly is a
window material safety data sheet for the crystal material itself that can
be consulted for safe handling. A copy of each of these datasheets can
also be found in this Gateway™ ATR instruction manual in the Notes
on Cleaning Section found on pages 42, 43 and 44.

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3. Checklist and Contents
The Gateway™ ATR Kit as P/N GS11165 is packed in protective
wrappings within its container box. The box contains the following:
•1 Gateway™ ATR incompartment
optical unit –GS11170.
•1 Trough top plate assembly with
45ZnSe crystal –GS11166.
•1 Flat top plate assembly with
45ZnSe crystal –GS11133.
•1 Clamp assembly –GS11171.

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•1 Pair of flexible purge
bellow tubes –GS10707.
•1 PTFE pad (used with
trough plate and clamp).
•1 Spatula (for spreading pastes or powders)
•1 Allen key - 2.0 mm A/F.
•1 Allen key - 2.5 mm A/F.
•1 Allen key –3.0 mm A/F.
•1 User instruction manual for the Gateway™ ATR Kit.
Note: An appropriate Benchmark™ baseplate for installation of the
optical unit into the spectrometer is supplied separately outside
the box of the Gateway™ Kit. A Benchmark™ Baseplate
installation guide is also provided to follow for fitting of the
appropriately supplied baseplate into the spectrometer.
Carefully remove the items from their packaging and prepare the
Gateway™ ATR Accessory for installation, alignment and use.

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4. Preparing the Gateway™ ATR Accessory
Before the Gateway™ ATR Accessory is to be installed and optimized
for its optical alignment within a particular spectrometer system to be
used, it is necessary to fit the clamp assembly (1) to the optical unit (2)
and also to fit either the trough (3) or flat (4) top plate crystal assembly
to the optical unit (2).
The Clamp Assembly (GS11171)
The clamp assembly (1) is supplied separately to the Gateway™
optical unit (2). Please use the following instructions to fit the clamp
assembly (1) to the Gateway™ optical unit (2).
Note: To avoid any accidental damage to certain parts, the clamp
assembly (1) should be fitted onto the Gateway™ optical unit
(2) without the trough (3) or flat (4) top plate crystal assembly in
position on the optical unit (2). Also, be careful when fitting the
clamp assembly (1) that the mirrors (movable - 5) and (fixed - 6)
on the optical unit (2) are not touched or scratched.
Fig 2. Gateway™ ATR Clamp Assembly
12
10
11
9
8
7
14
13

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The complete Gateway™ ATR clamp assembly (1) consists of a
movable (up and down) arm mechanism (7) which is locked into its
down position when the top T-bar handle (8) is pushed fully down and
closed. (As shown in Fig 2.) The arm mechanism (7), that is raised by
pulling up on the T-bar handle (8) or lowered by pressing down on the
T-bar handle (8), is connected to a pressure plate and pad assembly
(9) with use of an adjustable screw (10) for tensioning of a spring bar
(11). The pressure plate and pad assembly (9) provides the force
against a solid sample (in either solid, powder or film forms) to bring its
sampling surface into sufficient contact against the ATR crystal in a flat
top plate assembly (4) in order to obtain an ATR spectrum for the
sample. The screw (10) is turned in a clockwise direction by the rubber
knob piece (12) to exert more force on the spring bar (11) and
anticlockwise to reduce the force for tensioning of the spring bar (11),
which in turn adjusts accordingly for a sample force contact to the ATR
crystal.
The complete clamp assembly (1) is fitted to the optical unit (2) via a
black coloured clamp support block (13) and four M4 x 20mm cap
head screws (14).
Note: It is important that the clamp support block (13) is fitted the
correct way around on the optical unit (2) for correct positioning
of the clamp assembly (1) for its force application and clearance
of any fitted trough (3) or flat (4) top plate assembly. (See Fig 4).
Fixing the Clamp Assembly to the Optical Unit
1) Take the clamp assembly (1) and push down on the clamp T-bar
handle (8) to lower the pressure plate and pad (9) for a closed
position. This allows for clear access in fixing of the clamp
assembly (1) through the screw (14) holes via the support block
(13) to the optical unit (2).
2) Align the four clamp assembly fixing screws (14) with the four holes
in clamp assembly arm mechanism (7) to pass through these holes
first before passage through the screw holes in the support block
(13) and finally into the corresponding threaded fixing holes on the
top surface plate (15) of the optical unit (2). (See Fig 3.)

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Fig 3. Fixing the Clamp Assembly to the Optical Unit
Note: The support block (13) is orientated correctly as shown in Fig 3.
when the two screw holes of the four that are closest to the
edge of the support block (13) are facing towards the pressure
plate and pad assembly (9) for fitting. (Also see Fig 4.)
Fig 4. Orientation for Fitting of Support Block (13)
Threaded Screw Holes for Clamp Assembly Fixing
15
7
14
13
9
13
This Edge of the Support
Block (13) to be Facing
Forward and Towards the
Pressure Plate and Pad
Assembly (9)
12

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3) Using the larger 3mm A/F Allen key supplied, secure the clamp
assembly (1) to the Gateway optical unit (2) by clockwise rotation
for tightening of the four fixing screws (14) through the aligned
holes of the clamp assembly (1) and support block (13).
(Do not over tighten).
Fig 5. shows the clamp assembly (1) in its fully closed position with
some partial force being applied to the spring bar (11) from the
tensioning screw (10), as correctly fitted to the optical unit (2).
Fig 5. Gateway™ ATR Clamp Assembly Fitted to the Optical Unit
2
1
10
11
16
16

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Fitting the Trough or Flat Top Plate Assembly
When the clamp assembly (1) has been fitted to the optical unit (2), the
trough (3) or flat (4) top plate assembly can also be fitted to the optical
unit (2) prior to installation and alignment of the Gateway™ ATR
Accessory.
Note: The trough (3) or flat (4) top plate assembly can be fitted to and
removed from the optical unit (2) when it has been installed on
to its Benchmark™ baseplate within the spectrometer sample
compartment, but either top plate assembly must be fitted for a
necessary optimum alignment of the Gateway ATR accessory
to be made.
On either side of the top surface plate (15) of the optical unit (2) there
are two location pins (16). (See Fig 5.) At each end of the trough (3)
and flat (4) top plate assemblies there is a round hole and a slot hole
that passes all the way through the metalwork of these top plate
assemblies. The top plate assemblies are fitted into correct position
onto the top surface (15) of the optical unit (2) from alignment of the
round and slot holes of the plates (3) and (4) with these location pins
(16). (See Fig 6.)
Fig 6. Flat Top Plate and Clamp Assembly Employed as Fitted
to the Gateway™ ATR Optical Unit
Round Hole
Over Location
Pin (16)
Slot Hole
Over Location
Pin (16)

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In fitting of either top plate assembly into position over the location pins
(16), the pressure plate and pad assembly (9) of the clamp assembly
(1) must be lifted up and away to allow for the clearance in fit. When
the trough top plate assembly (3) is fitted, the clamp assembly (1) for
any sample force contact is normally not needed for any liquid
sampling so can be kept raised. If the flat top plate assembly (4) is
being used, once it has been fitted correctly and after any solid sample
type has been placed over and to cover the entire ATR crystal surface
area, the clamping mechanism is employed to force the sample into
suitable contact for an ATR spectral measurement to be made.
Trough (3) and Flat (4) Gateway ATR Top Plates
The trough (3) and flat (4) top plate assemblies provided with the
Gateway™ ATR Accessory have ZnSe ATR crystals (17) (P/N
GS11145) supplied in place for use. There are further crystal options of
Ge (P/N GS11147) and Si (P/N GS11146) available for use in both
trough (3) and flat (4) top plate assemblies. The crystals (17) have
been sealed into position by epoxy resin gluing for any flat (4) top plate
assembly, but in any trough (3) or flow through top plate assembly
the crystal (17) type options are removable. They are sealed for
sample containment over the ATR crystal (17) surface within these top
plate assemblies from use of specific gaskets made of Isolast or Kalrez
material.
The Trough Top Plate Assembly
The ATR crystal (17) in the trough (3) top plate assembly is held in
place within the surrounding plate metalwork (18) from a pressure bar
(19) that pushes against the underside of the crystal (17) via a lead
pad (20) and seals the crystals (17) top surface against an Isolast
gasket (21). A central M4 x 5mm grub screw (22) within a base support
plate (23) is tightened to provide the force to the pressure bar (19) for
sealing of the whole assembly of parts. The base support plate (23) is
held in place by four M3 x 12mm cap head screws (24). This design for
a trough (3) top plate assembly allows for removal of the crystal (17)
for cleaning or for a change of crystal (17) completely if damage has
been sustained or for use of an optional ATR crystal (17) material.
(See Fig 7. –Underside View.).

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Fig 7. Gateway™ ATR Accessory Trough Top Plate Assembly,
Top, Side (Cross Section) and Underside Views
17
21
18
23
21
17
20
22
23
19
17
18
24

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Crystal Removal from the Trough Top Plate Assembly
If the ATR crystal (17) from the trough (3) top plate assembly needs to
be removed for thorough cleaning or has become damaged and needs
replacing by a new crystal material of the same type or an alternative
crystal material, please use the following procedure.
1) Lay the complete trough (3) top plate assembly upside down on a
clean flat surface covered with soft tissue. Using the 2mm A/F
Allen key supplied, turn anticlockwise to loosen the central M4 x
5mm grub screw (22) that pressurizes the crystal assembly of
parts, but do not remove it from the base support plate (23).
2) Using the 2.5mm A/F Allen key supplied unscrew the four M3 x
12mm cap head screws (24) that secure the base support plate (23)
to the trough top plate metal work (18) and remove the support plate
(23) that is still holding the grub screw (22). Access can now be
gained to remove the pressure bar (19) and the lead pad (20) that is
in contact with the underside of the crystal (17).
3) Carefully remove the pressure bar (19) and lead pad (20) away
from the crystal (17).
Important: Take care not to damage the thin lead sheet of the pad
(20) between the pressure bar (19) and the crystal (17),
as it will need to be re-used for correct installation of a new
crystal (17).
4) Turn the trough (3) top plate assembly, still holding the crystal (17),
the correct way up to gently remove the crystal (17) out of its
retaining cavity. Be careful that the crystal (17) is not being loosely
held in place by the top Isolast gasket (21) seal and could fall out
accidently when the trough (3) top plate assembly is turned the
correct way up. Usually though, it may be necessary to loosen the
crystal (17) from the Isolast gasket (21) seal by exerting a small
pressure on either ends of the crystal from inside the trough area
of the top plate metal work (18) and pushing down from above.
Do not press too hard in case the crystal (17) breaks. (ZnSe, in
particular, is a hard, but brittle crystal material.)

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Tip: Using gloves and with the fore fingers of both hands covered with
soft lens tissue to prevent any scratching to the crystal (17)
surface, exert light even pressure on both ends of the crystal (17)
simultaneously from inside the trough.
With the crystal safely removed, if it needs cleaning please refer to the
Notes on Cleaning pages 40 and 41.
Changing the Isolast Gasket of the Trough Top Plate
Assembly
The Isolast gasket (21) seals around the top of the ATR crystal (17)
surface and between the trough area of the trough top plate metalwork
(18). It may be necessary to change the Isolast gasket (21) seal if
there is leakage of liquid sample away from the crystal surface area,
even after tightening of the pressure bar (19), or if the gasket (21) has
become contaminated and/or degraded from use. However, with any
removal of the ATR crystal (17), it is necessary to check the condition
of the Isolast gasket (21) before any crystal (17) replacement, so the
Isolast gasket (21) could be changed at this stage if desired.
Note: The Isolast gasket (21) seal usually only needs changing very
occasionally if careful use of the trough (3) top plate assembly is
observed. An Isolast gasket (21) replacement from P/N
GS11167 will be required.
To replace the Isolast gasket (21) in a trough (3) top plate assembly
please use the following procedure.
1) Carefully remove the ATR crystal (17) as described in the
procedure on pages 16 and 17.
2) Remove the Kalrez gasket (21) seal from the recess of the trough
top plate metal work (18). (See Fig 8.) Depending on its condition it
may come away in one piece or in fragments, but ensure that all
parts of the old Isolast gasket (21) are removed from the area.
3) Using a solvent such as acetone to moisten a soft, lint free cloth,
thoroughly clean the areas of the trough top plate metalwork (18)
where the Isolast gasket (21) had made contact.

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Fig 8. Isolast Gasket in the Trough Top Plate Assembly
4) Place a new Isolast gasket (21) seal (from P/N GS11167) in place
of the original seal, centrally in the recessed back face of the trough
top plate metal work (18). (See Fig 8.)Ensure that the gasket (21)
lays flat within and tight to the edges of the recess.
The trough (3) top plate assembly is now ready to accept a new
replacement or cleaned ATR crystal (17) for re-assembly to a working
and usable condition.
Re-assembly of the Trough Top Plate Assembly
After an ATR crystal (17) has been removed from the trough top plate
assembly and the Isolast gasket (21) (new replacement or the cleaned
original) has been positioned correctly in the trough top plate
metalwork (18), re-assembly of the trough (3) top plate can commence.
21
18