COOLSTAGE
SPECIMEN COOLING UNIT
MK3 FOR ZEISS
OPERATION MANUAL LT3.09
TENSILE TESTING
E-BEAM INSTRUMENTATION
DIGITAL IMAGING
© Deben UK Ltd. 2014
Deben UK Ltd.
Brickfields Business Park, Old Stowmarket Road
Woolpit, Bury St. Edmunds, Suffolk IP30 9QS. UK
Tel: +44 (0) 1359 244 870, Fax: +44 (0) 1359 244 879
Web: www.deben.co.uk E-mail: info@deben.co.uk
Registered in England and Wales No. 3208255
Registered Office: Unit 19 Charlwoods Road, East Grinstead,
West Sussex, RH19 2HL, UK
3005-0012
Specimen Cooling Unit, STANDARD MK3 LT3.09
Contents
Function
Page
Introduction
1
Operation
2
Setting temperature
3
Photo mode
4
Sample exchange
4
Command Summary
5
Appendix -A (storage)
7
Appendix -B (Water pipe connection)
8
Appendix -C (Refilling waterbox)
9
Appendix -D (Specimen Mounting)
10
Appendix -E (Troubleshooting)
11
EC declarations
12
Important notes
1. This manual relates to MK3 Coolstage units fitted to the following
Carl Zeiss SEMs, EVO, LEO and SUPRA.
2. The Peltier cold head is fragile and care should be taken when
handling. If dropped the performance may be degraded.
3. Never touch a surface which is below freezing with bare skin or a
cryogenic burn could occur.
Specimen Cooling Unit, STANDARD MK3 LT3.09
Introduction
The Deben Specimen Cooling Unit (SCU) consists of microprocessor
controlled solid state chiller unit with water circulation pump, a
compact keypad controller and a head unit assembly.
The head unit is fitted to the SEM stage via a vacuum flange which
carries the water and electrical connections. The specimen is cooled
with a single stage heat pump (Peltier), the hot side of the Peltier is
cooled by re-circulating water. Temperature of the specimen and the
cooling water is monitored simultaneously and set by PID loop from
the microprocessor.
The specimen holder has been designed to minimise image drift due
to temperature change, giving a stable image at high magnification.
Water level is monitored by a level sensor in the water reservoir,
when water level is low a message is displayed on the keypad display
and a warning LED is illuminated on the chiller unit. Water can be
easily refilled by removing the panel on the top of the chiller unit. For
full instructions see Appendix C.
An integrated RS-232 or USB interface allows the system to be fully
controlled externally from a computer.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Operation
The chiller unit should be switched on for about 30 minutes before
use, this allows the cooling water to reach operating temperature.
Failure to do this may result in the system not reaching the desired
temperature.
All functions of the SCU are controlled from the small keypad
controller, current status is displayed on the vacuum fluorescent
display along with the current and target temperature.
When using the system we recommend that ambient (room)
temperature is between 20ºC and 25ºC, care should be taken to
ensure that the chiller unit has good airflow around it and is not
positioned directly next to a heating vent or the SEM power supply.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Setting Temperature
After the system has been switched on for about 30 minutes the
cooling water will be chilled to about 8ºC below ambient temperature.
This in turn will cool the specimen and the temperature will be shown
on the display.
To set the specimen holder temperature press auto, required
temperature is then adjusted using the up/down arrow keys. As an
alternative the goto key allows the target temperature to be entered
from the keypad (using the numeral keys).
Maximum cooling rate is 30°C/min and maximum heating rate is
20ºC/min. At the upper and lower end of the temperature range
cooling/heating rate will be lower.
Temperatures may be set in the range of -30ºC to +50ºC or -10ºF to
+120ºF.
At any time after heating or cooling the off button may be pressed
which will switch off the specimen peltier device and the specimen
holder will slowly reach 8ºC below ambient temperature.
Minimum temperature (-30ºC) will only be obtainable when operating
under vacuum of at least 50pa, at 300pa we guarantee at least -25ºC.
Normally only approximately -20ºC will be possible at atmospheric
pressure (and then only with ambient of 15ºC or below).
When using the SCU to look at wet samples you should start to cool
the specimen holder just before pumping the chamber, the exact time
will depend on the sample, the microscope and environmental
conditions (ambient temperature). An initial amount of experimentation
will be necessary to determine the exact timing required.
IMPORTANT NOTE
The Coolstage chassis should be switched on for around 30
minutes before use, to allow the cooling water to reach the
correct temperature.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Photo Mode
The photo button is for use when taking a photo on the SEM to ensure
that no image shift is seen on the resultant image.
To use, select the required temperature and when the temperature
has been reached press the photo button and the current through the
Peltier device will be fixed.
You will see a slight change in temperature of approximately 0.1º per
minute - (this is normal). After taking the photo press the auto button
and the SCU will switch back to controlling the temperature as normal.
IMPORTANT NOTE:
Do not press photo while the temperature is still increasing or
decreasing, otherwise the Peltier current will be fixed at this level
and will not stop at the desired level but continue rising or falling.
Sample Exchange
When exchanging the sample or bringing the vacuum chamber up to
atmosphere pressure after using the SCU at temperatures below
ambient, you should first increase the specimen holder temperature to
ensure that condensation does not form on the specimen/specimen
holder.
The exch button will automatically take the specimen holder
temperature to a programmable temperature from between 5ºC to
20ºC.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Command Summary
off
- Switches Peltier device off (cooling or heating). Sample will
slowly reach ambient temperature.
auto
- Sets the controller to control the sample temperature. The
required temperature is set using the up/down keys on the
controller. Normally the increment is 0.5ºC.
goto
- Temperature can be entered from the keypad. The delete
key acts as the minus key. Acceptable values lie in the range
of -25ºC to +50ºC or -10ºF to +120ºF.
step
- Toggles the increment for temperature setting, 0.5ºC is the
default but it can be toggled to 0.1ºC.
up/down - Increases or decreases the set temperature.
cal
-Setup and display routines:
1 - displays the Peltier device current.
2 - hides the Peltier device current (default).
3 - displays the heatsink temperature (typically 20-30ºC).
4 - sets the sample exchange temperature (5-20ºC).
7 - sets the temperature control loop gain (default = 5).
8 -sets manual mode (only operates if Peltier device is
switched off first).
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Specimen Cooling Unit, STANDARD MK3 LT3.09
photo - Switches off the closed loop temperature control. The Peltier
device current will remain constant, although the temperature
may change slightly.
exch
- Sets the sample temperature to the pre-programmed
exchange temperature.
ºC/ºF
- Changes the temperature display from degrees Centigrade
to Fahrenheit.
del
- Cancel or minus key.
enter
- Accept.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Appendix - A - storage of SCU
When the SCU is not fitted to the Microscope it should be fitted to the
supplied mounting block to ensure safe keeping. The flange will fit into
a slot, a hole is provided for the specimen holder. If required, the
releasable tie-wraps (supplied) can be used to secure the parts in
place as shown below.
WARNING
The Peltier cold head is fragile and care should be taken when
handling. If dropped the performance may be degraded.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Appendix - B – Connecting and disconnecting water pipes and
cables
The unit is fitted with quick release connections for the cool head
water pipes and power cable.
To connect up the water pipes simply push them on and the
connectors should lock into place. It does not matter which pipe is
connected to which outlet. To connect up the cool head power cable;
line up the slot on the plug to the location pin at the top of the socket
(mounted on the front of the chassis) and then simply push the plug in
and it should lock into place.
To disconnect the cool head water pipes and cable simply pull on the
quick release latches and the connectors should easily come off. Do
not remove connections when system is on. The valves will
automatically shut off if the water pipes are disconnected when the
system is on. However, a small amount of water may be lost due to
the time taken for the valves to close fully. For this reason it is
important that the system is switched off before removing any
connectors.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Appendix - C – Refilling waterbox
Over time there may be some water lost in the cooling unit though
evaporation and the removal of the water pipe connections. Because
of this the chiller unit has been fitted with a water level sensor. When
the water needs to be refilled the water level LED (located on the front
of the chiller unit) will illuminate and the pump will automatically switch
off, at the same time a warning message will be displayed on the
controller display, while the unit is in this state cooling and heating of
samples will not be possible. The water will need to be filled before the
unit will function again.
To refill the water remove the cover located on top of the chiller unit.
Undo the yellow screw cap to expose the water reservoir. Refill
waterbox (use de-ionised water only) as shown below.
Do not over fill the waterbox, fill only up to the top of the brass edges
seen in the waterbox.
Replace yellow waterbox screw cap and water refill cover.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Appendix - D – Specimen Mounting
Flat stubs using Cryo-Gel Embedding Medium
Cryo-Gel Embedding Medium is available from Agar Scientific (Part
number L4383) and is ideal for mounting wet organic specimens with
uneven surfaces.
1. Mount flat stub onto Coolstage.
2.
Place a 2-3mm diameter drop of Cryo-Gel onto the top surface of the
stub.
3. Using tweezers, place the sample directly onto the Cryo-Gel if
possible push the specimen down into the gel, the Gel will act as a
thermal transfer medium and hold the specimen in place while
imaging.
Flat stubs using Double sided Carbon Tabs
Carbon tabs are available from most consumable companies and are
ideal for mounting dry specimens and powders.
1. Mount flat stub onto Coolstage.
2. Remove adhesive from one side of the carbon tab and place on
Coolstage stub.
3. Pull the stub off the adhesive sheet to expose the other side of the
adhesive pad.
4. Place the sample on top of the exposed adhesive; ensure the
sample is firmly attached.
Dished stubs
Dished stubs are designed to hold a small amount of liquid with the
specimen suspended within the liquid
1. Mount dished stub onto Coolstage.
2. Place a drop of water or other liquid into the dished stub, place the
specimen onto or into the drop of liquid.
3. Set the temperature to around 0°C to freeze the specimen onto
the stub.
Once the specimen is mounted we recommend that you start cooling
immediately and wait until the temperature display reaches 0°C before
pressing “Pump” on the microscope.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
Appendix E – Coolstage Troubleshooting
Problem:
Solution:
Interference when saving an image.
Make sure “Photo” button is pressed prior to
saving image.
Problem:
Solution:
-25°C is not reached.
a. Ensure chiller has been switched on
for 30 minutes
b. Ensure that room temperature is less than
25°C
c. Ensure sample is not too large; maximum size
is 10mm diameter x 5mm high.
Problem:
Solution:
Alarm sounds.
Refill water reservoir (Appendix C)
Problem:
Solution:
Pump in chiller makes noises.
Switch system on and off three times to try and
remove trapped air. Wait 10 seconds between
switching.
Problem:
Solution:
Frosting of the coolhead.
Bring specimen to room temperature before
venting SEM chamber. Press “Exchange” on the
Coolstage keypad and wait for the frost to thaw.
Ensure that you wipe up any water that remains
following thawing.
Problem:
Solution:
Over temperature alarm is activated.
Switch system on and off three times to try and
remove trapped air. Wait 10 seconds between
switching.
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Specimen Cooling Unit, STANDARD MK3 LT3.09
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Specimen Cooling Unit, STANDARD MK3 LT3.09
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Specimen Cooling Unit, STANDARD MK3 LT3.09
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Deben UK Ltd.
Brickfields Business Park, Old Stowmarket Road
Woolpit, Bury St. Edmunds, Suffolk IP30 9QS. UK
Tel: +44 (0) 1359 244 870, Fax: +44 (0) 1359 244 879
Web: www.deben.co.uk E-mail: info@deben.co.uk