Specac Gateway ATR User manual

Gateway™ ATR Water Heated
Trough Top Plate
User Manual
2I-11139 Issue 5

Gateway™ ATR Water Heated
Trough Top Plate
User Manual
2I-11139 Issue 5

User Manual
2
Gateway™ ATR Water Heated Trough Top
Plate P/N GS11139
CONTENTS
1. INTRODUCTION .................................................................................3
2. SAFETY CONSIDERATIONS ................................................................5
3. UNPACKING AND CHECKLIST .............................................................6
4. ALIGNMENT OF THE GATEWAY™ATR HEATED TROUGH TOP PLATE ..7
FITTING THE GATEWAY™ATR HEATED TROUGH TOP PLATE.............8
5. ANALYSING LIQUID SAMPLE TYPES..................................................10
THERMOCIRCULATING PORTS (5)AND (6)CONNECTION ...................10
LIQUID SAMPLING...........................................................................12
PASTE SAMPLES ............................................................................13
6. ATR CRYSTAL REMOVAL AND REPLACEMENT ..................................15
CRYSTAL REMOVAL FROM THE HEATED TROUGH TOP PLATE ............15
CHANGING THE KALREZ GASKET.....................................................17
REPLACING THE CRYSTAL IN THE TOP PLATE ASSEMBLY ..................18
CLEANING THE GATEWAY™ATR HEATED TROUGH TOP
PLATE INTACT................................................................................20
NOTES ON CLEANING......................................................................20
DATA SHEET FOR ZINC SELENIDE....................................................23
DATA SHEET FOR GERMANIUM........................................................24
DATA SHEET FOR SILICON ..............................................................25
7. GATEWAY™ATR HEATED TROUGH TOP PLATE "BUBBLE NUMBER"
PART IDENTIFICATION.....................................................................26
8. GATEWAY™ATR HEATED TROUGH TOP PLATE SPARE PARTS ........26
9. GATEWAY™ATR TECHNICAL SPECIFICATION…...............................27
10.GATEWAY™ATR HEATED TROUGH TOP PLATE SERIAL NUMBER...28
© 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.

Gateway™ ATR Water Heated Trough Top Plate
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1. Introduction
Thank you for purchasing a Specac Product.
This user instruction manual for the Gateway™ ATR Water Heated
Trough Top Plate P/N GS11139 is to be used in conjunction with the
user instruction manual provided for the Gateway™ 6 Reflection ATR
Accessory against P/N GS11165 (2I-11165-4). Understanding of the
Gateway™ ATR Accessory itself helps in usage of any alternative ATR
Top Plates that are compatible with this ATR system.
The Gateway™ ATR Water Heated Trough Top Plate P/N GS11139 is
an alternative Top Plate that can be used on the optical unit (P/N
GS11170) of the Gateway™ ATR Accessory. The Gateway™ ATR
Accessory supplied as standard for a kit of parts under P/N GS11165,
provides for an optical unit (GS11170), a trough top plate assembly
fitted with a 45° ZnSe crystal (GS11166), a flat top plate assembly
fitted with a 45° ZnSe crystal (GS11133) and a clamp assembly
(GS11171). (See user instruction manual 2I-11165-4).
Note: Any Gateway™ ATR Top Plate assembly can also be used on
older Benchmark™ ATR optical units, P/N’s GS11160, GS11110
and GS11180.
Using the Gateway™ ATR Water Heated Trough Top Plate in
conjunction with any of the above optical unit systems, a liquid sample
can be held static over a 6 Reflection event ATR crystal to be studied
from ambient up to 130°C temperatures in operation. The temperature
maximum is determined from the type of heated fluid (water or oil)
provided via a thermocirculating system such as that offered by
Specac P/N GS11127. Chemical interactions for the mixing of sample
species at varying temperatures may also be monitored. (e.g. a solid
sample can be deposited onto the ATR crystal and a fluid can be
placed over the sample to observe any changes spectroscopically.)
The Gateway™ ATR Water Heated Trough Top Plate has been
designed with the capability to remove the ATR crystal for thorough
cleaning or using a replacement ATR crystal material in the Top Plate

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if desired. Any of the crystal materials usable with the Gateway™ATR
system –ZnSe, germanium or silicon –can be placed into the
Gateway™ ATR Flow Through Top Plate, although germanium loses
its spectral IR transmission capability with a progressive rise in
temperature, becoming completely opaque at temperatures of circa
100°C and above.
As a standard offering for P/N GS11155, a 45° angle ZnSe crystal (P/N
GS11145) is fitted. The ATR crystal options are:
P/N GS11145 - Gateway™ ZnSe crystal, 45° angle.
P/N GS11146 - Gateway™ Silicon crystal, 45° angle.
P/N GS11147 - Gateway™ Germanium crystal, 45° angle.
Fig 1. Gateway™ ATR Water Heated Trough Top Plate

Gateway™ ATR Water Heated Trough Top Plate
5
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 the Gateway™ ATR instruction manual (2I-11165-4) in
the Notes on Cleaning Section found on pages 42, 43 and 44.

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3. Unpacking and Checklist
The Gateway™ ATR Water Heated Trough Top Plate is supplied
packed in a black plastic carry case.
The carry case contains the following:
•Water Heated Trough Top Plate with
Zinc Selenide crystal (or as specified
from germanium and silicon options).
•ATR spectrum of the crystal as fitted to the Top Plate assembly to
show its background throughput.
•Clear silicone tubing for Thermostabilised fluid flow connectivity
1/4” O.D, 1/8” I.D.
•Plastic spatula.
•Allen Key (2.5mm A/F)
Remove the items carefully from their packaging in preparation for
installation and use.

Gateway™ ATR Water Heated Trough Top Plate
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4. Alignment of the Gateway™ ATR Water
Heated Trough Top Plate
The Gateway™ ATR Water Heated Trough Top Plate is to be installed
onto the optical unit (GS11170) of the Gateway™ ATR Accessory for
operation in the study of static liquids or paste samples over the
temperature conditions from ambient to 130°C. This Trough Top Plate
should be optimised for its energy light throughput from a particular
alignment of the mirrors on the optical when installed for use.
If the Gateway™ ATR Accessory (as the Kit GS11165) is available for
use, please follow the instruction manual supplied (2I-11165-4) for the
alignment procedure to optimize the liqht energy throughput of the ATR
system on your particular spectrometer using either the Trough Top
Plate (GS11166) or Flat Top Plate (GS11133) assembly as supplied.
The input and output mirror settings for their rotation and tilt angles will
be established on the optical unit (GS11170) from the alignment
procedure using either of these two Top Plates.
When subsequently placing the Water Heated Trough Top Plate onto
the optical unit as a replacement for either the Trough (GS11166) or
Flat (GS11133) Top Plate assembly, a signal throughput will be
registered, but it is possible the mirrors in the optical unit may require
slight re-adjustment for an optimum throughput to be established in
use of this alternative Trough Top Plate. Therefore, follow the
alignment procedure with the Water Heated Trough Top Plate in
position to obtain the best throughput energy signal for the
spectrometers system.
Note: If just the Gateway™ optical unit (GS11170) and a Water
Heated Trough Top Plate are available to use, unless the optical
unit has been pre-aligned to register some energy throughput
with a Top Plate in position, then it may be difficult to gain an
optimum alignment using the FTIR spectrometer systems energy
source and detection system. A rough pre-alignment is to be
established with the optical unit and Water Heated Trough Top
Plate in position using a visible light source such as the Laser
Alignment Accessory (P/N GS24500).

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Fitting the Gateway™ ATR Water Heated Trough Top Plate
The Gateway™ ATR Water Heated Trough Top Plate fits onto the top
of the Gateway optical unit via alignment of the round hole (1) and slot
hole (2) on the underside of the Top Plate over the two fixing location
pins (3) on the optical unit. (See Fig 2 and Fig 3.)
Fig 2. Round and Slot Location Holes on Underside of
Gateway™ ATR Water Heated Trough Top Plate
The Gateway™ ATR Water Heated Trough Top Plate is fitted and
positioned the correct way around on the optical unit when the round
hole (1) is placed over the right side location pin (3R) and the slot hole
(2) is placed over the left side location pin (3L) as viewed from the
front of the optical unit. The main body plate (4) of the Top Plate
should be sitting flush and even all the way around its edge onto the
top surface of the optical unit when properly located.
Note: To maintain a correct optical alignment for consistency of optical
throughput energy of the Gateway™ ATR Water Heated Trough
Top Plate, it should always be placed onto the optical unit the
same way around after removal for cleaning or crystal
replacement etc, with the round (1) and slot (2) holes fitting over
their correct and respective fixing location pins (3R) and (3L).
2
1
4

Gateway™ ATR Water Heated Trough Top Plate
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Fig 3. Fitting of Gateway™ ATR Water Heated Trough
Top Plate to the Gateway™ Optical Unit
1
2
4
3L
3R
R

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5. Analysing Liquid Sample Types
When the Gateway™ ATR Water Heated Trough Top Plate has been
correctly installed onto the optical unit and aligned, then operation for
collection of a background spectrum and then a sample spectrum can
begin. (Please see Spectral Collection Using the Gateway™ ATR
Accessory from the instruction manual 2I-11165-4).
In operation for collection of a background spectrum and then a
sample spectrum, ideally the temperature conditions for both spectral
acquisitions should be the same. When using a thermocirculating
system to provide heat to the Top Plate assembly care must be
exercised that the temperature rate rise being provided by the
thermocirculating system does not exceed 10°C per minute. Any
higher rate rise risks introducing thermal shock to the ATR crystal (7) in
the Top Plate assembly and causing damage.
When using the Gateway™ ATR Water Heated Trough Top Plate for
liquid sampling it is essential that all the tubing connections are well
secured to the thermocirculating fluid connection ports (5) and (6) of
the Top Plate assembly.
Important: All tubing connected to the ports (5) and (6) on the Top
Plate should be tested initially for liquid flow away from
installation on to the optical unit. This avoids any
accidental spillage of fluid onto the optical unit should the
flow tubes not happen to be well secured.
Thermocirculating Ports (5) and (6) Connection
To establish different temperatures of operation for measurement of a
sample fluid when in contact with the ATR crystal (7) of the Water
Heated Trough Top Plate, a thermocirculating fluid (water or oil) is
flowed entirely around the ATR crystal (7) held within the Top Plate
assembly. There are two flow connection ports (5) attached to the main
body plate (4) at its rear when the Top Plate assembly is fitted to the
optical unit and two flow connection ports (6) attached to the lower
thermocirculating plate (8). (See Fig 4.)

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Fig 4. Thermocirculating Connection Ports on Gateway™ ATR
Water Heated Trough Top Plate
Either of the two flow connection ports at (5) and (6) can be used as
the inlet or outlet port for a thermocirculating fluid to flow around the
main body plate (4) and lower thermocirculating plate (8) respectively,
but to provide for a flow of thermocirculating fluid around the entire Top
Plate assembly, the outlet port (6) of the lower thermocirculating
plate (8) MUST be connected to the inlet port (5) of the main body
plate (4).
Note: Connection of a thermocirculating fluid flow from the lower level
plate (8) to the upper level plate (4) helps to remove any air
pockets that may be trapped in the flow system. In addition,
appropriate connections to either the main body (4) or lower (8)
thermocirculating sections, mean they could be heated
independently of each other if desired.
The clear silicone tubing supplied has dimensions of 1/4" O.D. and 1/8”
I.D. and is pushed over the barbed hose type connectors on the inlet
and outlet thermocirculating flow ports (5) and (6). Tie wraps can be
placed around the tubing at the flow port (6) and (7) connections to
6
4
8
5
5

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prevent the tubing from separating under a thermocirculating liquid
sample flow. Connect the other ends of the clear silicone tubing that
has been attached to the inlet port (6) and outlet port (5) to a
thermocirculating pump delivery system and follow the instructions for
operation of the system being used for the thermocirculating fluid flow.
(An example of such a system supplied by Specac for use is the
Thermostatic Bath P/N GS11127).
In operation when running at elevated temperatures for any spectral
measurements, establish a flow of thermocirculating fluid around the
Top Plate and tubing system and then slowly raise the temperature of
the thermocirculating fluid to the desired operating conditions. A
gradual increase of temperature to a static liquid sample held in the
trough area reduces the risk of thermal shock to the ATR crystal (7).
Liquid Sampling
Liquids can be poured onto the crystal (7) of the Gateway™ ATR
Water Heated Trough Top Plate or introduced by the use of a pasteur
pipette. (See Fig 5.)
Fig 5. Sampling Area of Gateway™ ATR Water Heated
Trough Top Plate
4
7

Gateway™ ATR Water Heated Trough Top Plate
13
The liquid should cover the entire ATR crystal (7) surface where the
sample is being heated. It is important that a sufficient volume of
sample is applied so that the crystal (7) is not left exposed during any
spectral measurement, if there is any vaporization of the sample
because of an elevation in the temperature above ambient conditions.
As much of a liquid sample should be removed from the crystal (7)
area with a pasteur pipette when the Water Heated Trough Top Plate
assembly is cool to touch if any elevated temperature measurements
have been taken. It is recommended that the Water Heated Trough
Top Plate is also removed away from the optical unit to a safe area for
cleaning before introducing the next sample or after use. This prevents
potential accidental contamination of the optical unit parts and the
sample compartment area of the spectrometer.
If the liquid sample solidifies against the ATR crystal (7) when the Top
Plate assembly cools from an elevated temperature measurement, it
may be easier to remove most of the sample when hot, by very
carefully using the pipette and wiping the remainder of any sample
away from the ATR crystal (7) with a soft lens cleaning tissues while
cooling. Remove the last traces of the sample when the Top Plate
assembly has cooled sufficiently to handle by using fresh tissues
soaked in a suitable solvent.
Warning: Do not remove the Water Heated Trough Top
Plate for cleaning when hot as it can cause serious burns.
Paste Samples
Apply the paste lightly to cover the ATR crystal (7) surface completely
using the plastic spatula as supplied.
Similar to liquid sample handling, remove the sample by wiping clean
using a soft lens cleaning tissues when the top plate has cooled
sufficiently. Remove the last traces of the sample by using fresh
tissues soaked in a suitable solvent.

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If the paste sample solidifies against the ATR crystal (7) when the Top
Plate assembly cools from an elevated temperature measurement, it
may be easier to remove most of the sample when hot, by very
carefully using soft lens cleaning tissues to wipe the sample clear of
the crystal (6) while cooling. Remove the last traces of the sample
when the Top Plate assembly has cooled sufficiently to handle by
using fresh tissues soaked in a suitable solvent.
Warning: Do not remove the Heated Trough Top Plate for
cleaning when hot as it can cause serious burns.

Gateway™ ATR Water Heated Trough Top Plate
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6. ATR Crystal Removal and Replacement
The design of the Gateway™ ATR Water Heated Trough Top Plate
allows for the ATR crystal (7) to be removable for easier cleaning or if
damage occurs and the crystal needs to be replaced.
Crystal Removal from the Water Heated Trough Top Plate
If it is necessary to remove the crystal (7) for thorough cleaning of the
Top Plate assembly of parts or to replace any damaged parts etc, the
following procedure should be adopted.
Note:It is normally easier to work on the Top Plate assembly having
disconnected the silicone flow tubing from the thermocirculating
fluid flow ports (5) and (6).
Important: For safety precautions wear gloves when carrying out
the following procedure.
1) Lay the Top Plate assembly on to a clean workspace area and
proceed to remove the four M3 x 10mm cap head screws (9) from
the lower thermocirculating plate (8) using the 2.5mm A/F Allen key
supplied. Turn the screws (9) anticlockwise to remove. (See Fig 6.)
Fig 6. Underside of Water Heated Trough Top Plate Assembly
9
4
8
9

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Note: The lower thermocirculating plate (8) also acts as a pressure
clamp plate to force the internal ATR crystal (7), lead pad (10)
and Kalrez gasket (11) components assembly together for leak
tight sealing of the Top Plate.
2) Between the underside of the lower thermocirculating plate (8) and
the ATR crystal (7) there is a protective lead pad (10). Carefully
remove the lower thermocirculating plate (8) away to gain access to
the lead pad (10). (See Fig 7.) The lead pad (10) may be stuck
close to the underside of the crystal (7) and so it needs to be
removed very carefully away from the crystal.
Note: The lead pad (10) will be needed in any re-assembly after
cleaning of parts or if replacing with a new crystal (7).
Fig 7. Lead Pad on Underside of ATR Crystal with Removal of
Lower Thermocirculating Plate Assembly
3) If the lead pad (10) has adhered to the crystal (7), then it may be
easier to remove it carefully away from the crystal when the crystal
(7) itself has been removed from its centralised position in its
recess of the main body plate (4). Therefore, support the crystal (7)
4
10
7

Gateway™ ATR Water Heated Trough Top Plate
17
and the lead pad (10), with one hand and turn over the Top Plate
assembly so that the crystal (7) can fall out to drop into the palm of
your hand. If the crystal (7) is also stuck in the main body plate (4)
because of good sealing to the Kalrez gasket (11) on the top
(sampling) surface of the crystal (7), then put a soft pad or tissue on
the work bench area and lay the Top Plate assembly onto it the
same way up as it would be used when fitted to the optical unit.
Try to loosen the crystal (7) away from the Kalrez gasket (11) seal
by exerting a small pressure on either ends of the top of the crystal
(7) from inside the trough area and pushing down from above. Do
not press too hard in case the crystal (7) breaks. (ZnSe, in
particular, is a hard, but brittle crystal material.) If the crystal is
stubborn to movement try to lubricate the internal trough and Kalrez
gasket (11) area by use of some solvent (e.g. methanol) covering
the top surface of the crystal (7) whilst exerting the gentle pressure.
When the crystal (7) and the lead pad (10) have been removed, it may
now be easier to separate the lead pad (10) from the crystal. If the
crystals (7) top sampling surface looks OK and can be cleaned
carefully, then it may not be necessary to remove the lead pad (10)
away for further cleaning prior to re-assembly and use. However, if the
lead pad (10) is to be removed, it may be necessary to immerse the
whole crystal (7) and lead pad (10) assembly in a beaker of water or
methanol solvent and apply a gentle “sonication cleaning”of the items.
The action of the sonic agitation of the solvent may help to loosen the
lead pad (10) away from the crystal such that when the items are
removed from the solvent they can be easily and safely separated
without any damage to the lead pad (12) or crystal (7) parts.
Clean the ATR crystal (7) by following the Notes on Cleaning
instructions on page 20.
Changing the Kalrez Gasket Seal
When the ATR crystal (7) has been removed from the Top Plate
assembly, access can be gained to the Kalrez gasket seal (11) for
cleaning or replacement with new if necessary. (See Fig 8.)

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Fig 8. Kalrez Gasket Seal in the Gateway™ ATR
Water Heated Trough Top Plate
The Kalrez gasket seal (11) is supplied already pre-cut to fit and is
purchased against P/N GS11153. Should the Kalrez gasket (11) be
worn or damaged after inspection then replace with a new example. If
changing for a new gasket (11), ensure that all parts of the old gasket
are removed from the surface of the main body plate (4) to provide a
good surface for resealing. It does not matter which surface side of the
Kalrez gasket (11) is placed into contact with either the underside of
the trough area of the main body plate (4) or the top surface of the
crystal (7).
Replacing the Crystal in the Top Plate Assembly
1) Having cleaned all of the parts sufficiently and whether installing a
new crystal (7) and/or new Kalrez gasket (11), re-assemble the
Gateway™ ATR Water Heated Trough Top Plate first by aligning
correctly and centrally the Kalrez gasket seal (11) into the underside
channel recess of the main body plate (4). (See as Fig 8.)
2) Insert the ATR crystal (7) into the recess channel of the main body
plate (4) with the longer top surface of the crystal pressing against
11
4