The OptistatTMDry TLEX model provides a temperature controlled sample-in-exchange-gas environment, making it the most versatile Cryofree® or cryogen free top loading cryostat, optimised for different spectroscopy experiments.

The OptistatDry Cryofree® family of cryostats for spectroscopy cool samples to helium temperatures without the need for liquid cryogens. It comprises a range of compact cryostats with optical access cooled by a closed cycle refrigerator. They provide significant benefits in terms of ease of use and running costs. The systems enable optical and electrical measurements to be carried out on your samples. These are part of our high performance Optistat family.

Exchange gas environment

The OptistatDry - TLEX model is ideal for samples that have low thermal conductivity, including powder or are in liquid form. Samples for biological, life science or chemistry experiments often can not go into a vacuum environment. The OptistatDry with its sample-in-exchange-gas environment provides all the cooling you need for samples that are not suited for a vacuum environment.

Top loading capability

The OptistatDry - TLEX model is also perfect, regardless of what type of samples you have, if you need to minimise the time between experiments and maximise sample throughput. Removing the sample rod whilst the cryostat is kept cold enables you to swap from one sample to the next in just a few minutes. You can leave the cryostat in situ on the optical bench during sample change, eliminating the need for time-consuming re-alignment of your optical set-up.

OptistatDry - TLEX model featuresOptistatDry TLEX top loader windows

  • Wide sample temperature range from <4 to 300 K
  • Quick sample change in less than 5 minutes via top loading probe
  • A wide range of different sample holders, windows and wiring options enable you to upgrade your system as your experimental needs develop
  • No liquid cryogens are required
  • Optimised optical access with f1 and a clear view of 15 mm diameter
  • Water and air-cooled compressor options available

Main benefits overview

The OptistatDry TLEX model is designed to be:


  • Ideal for a wide range of spectroscopy applications including Raman, FTIR, Photoluminescence, etc.
  • Designed to interface with all types of optical benches; the feet match both Imperial (1 inch spacing) and metric (25 mm spacing)


  • Designed with a modular philosophy that allows the cryostat to evolve with your experiment, allowing you to start with a basic system and as experimental needs change, upgrade to additional functionality at a later date, for example, add extra wiring, different sample holders and windows
  • A wide range of different sample holders, windows and wiring options enable you to upgrade your system as your experimental needs develop

Optical excellence

  • The cryostat comes with f1 and large clear optical access as standard
  • A wide range of different window materials are available to suit different wavelengths; wedged windows and anti-reflection coatings are also available

Simple to use

  • No liquid cryogens are required
  • Air or water-cooled compressors are available; single phase electrical power means the system is easy to install in all standard laboratory environments


Sample temperature range < 4 K to 300 K
Measured temperature stability ± 0.1 K
Cooling power ~ 0.2 W at 5 K
Sample space size 20 mm diameter
Sample cool down to 10 K with cryostat cold ~ 45 minutes
Cryostat cool down to 10 K ~ 360 minutes
Optical access - f number f1
Optical access - clear view 15 mm diameter


Here are some of the applications the OptistatDry - TLEX model is ideally suited for:

UV/Visible spectroscopy Experiments at low temperatures reveal the interaction between the electronic energy levels and vibrational modes in solids
Infrared spectroscopy Low temperature IR spectroscopy is used to measure changes in interatomic vibrational modes as well as other phenomena, such as the energy gap in a superconductor below its transition temperature
Raman spectroscopy Lower temperatures result in narrower lines associated with the observed Raman excitations
Photoluminescence At low temperatures, spectral features are sharper and more intense, thereby increasing the amount of information available
Electrical properties Optical and electrical measurements including I-V curves


OptistatDry TLEX model - sample holders and wiring options

Sample holders and wiring options

The OptistatDry TLEX model comes complete with its own built-in diagnostic wiring, heater and sensor, which are wired to a 15 way micro D-type connector mounted on the room temperature connector flange of the cryostat.

Sample holder options  

Standard sample holder for optical measurements

These sample holders are ideal for optical measurements. They are made from nickel plated copper. The SH1 is best suited to reflection measurements. It provides a flat surface 19 mm x 19 mm to mount your sample. The SH3 is best suited to transmission measurements. It provides a 15 mm clear diameter hole and a clamp plate to secure your sample.

Wiring options:

Experimental wiring can also be chosen as an option with the standard sample holders. A wide range of experimental wiring options is available including DC, RF and sample probe heater/sensor options.

Standard sample holder for liquid samples

The SH7 sample holder and CV cuvette are ideal for liquid or powder samples.

SH7 sample holder and CV cuvette - ideal for liquid or powder samples


OptistatDry TLEX model - accessories

MercuryiTC temperature controller

The MercuryiTC temperature controller is ideally suited to monitor and control the OptistatDry. It has one PID loop to read the sensor and control the heater mounted on the cryostat. It is very easy to operate from the touch screen user interface. You can connect to the MercuryiTC via multiple interfaces: Ethernet, USB or GPIB (optional).  For details , click here.

Window options

We offer a wide range of window options to suit your experimental needs, covering wavelengths from UV all the way to the extreme IR.

For further details about the available window options, click here.



Vacuum pump options

The OptistatDry needs to be pumped to a pressure of 10-4 mbar before it is cooled down. It needs to be re-pumped every time the sample is changed. A dry turbo pump is recommended for this, the H4-600 and H4-601 are both ideal for the OptistatDry. The H4-601 comes with a vacuum gauge making it easier to know when the cryostat has been pumped down sufficiently to start cooling.







OptistatDry spares kit

The spares kit includes all the tools needed to install and maintain your system including tools for fitting the helium compressor lines; screw drivers for the screws used on the system; replacement o-rings; and screws for the regularly accessed parts.


OptistatDry TLEX model - principle of operation

The Optistat™Dry is based on a Gifford-McMahon (GM) Cryocooler. The major components in the cooling system are the cold head (Sumitomo RDK-101D), the compressor (either water or air-cooled) and high pressure lines. They form the basis of a sealed circuit containing helium gas which is used as the cooling medium. The cold head is where the Gifford-McMahon refrigeration cycle takes place. It is connected to a compressor by two gas lines and an electrical power cable. One of the gas lines supplies high pressure helium gas to the cold head, the other gas line returns low pressure helium gas to the compressor. The compressor provides the necessary helium gas flow rate at the high and low pressure for the cold head to convert into the desired cooling power at the first and second stages of the cold head.


OptistatDry TLEX model - why go Cryofree?

OptistatDry TLEX model - the new optical cryostat for spectroscopy

An ever growing number of institutes are choosing cryogen free optical cryostats such as the OptistatDry. These decisions are driven by a number of important factors. Use the following online cost calculator to find out the annual saving you can have, simply by switching over to a Cryofree OptistatDry:

Just answer the following question to discover how much you could save by making the switch today:

1. What is your current cost per litre of liquid cryogen?

2. Typically, how many hours of experimentation per week?  HOURS

3. How many weeks in the year will your experiment be running for?  WEEKS


Important factors to consider

Cost of liquid cryogens


The cost of liquid cryogens continues to rise placing an increasing financial burden on institutes. The OptistatDry uses no liquid cryogen at all, and this could save you a substantial amount of money compared to using a wet cryostat. The calculator above can show you the saving you can have.

Availability of liquid cryogens


Scheduling experiments is difficult but having to factor in when you will have liquid cryogen makes it even harder. When the rate at which you can publish papers is limited by the availability of liquid cryogens, it is time to consider a cryogen free OptistatDry. As long as you have electrical power you can run cryogenic experiments 24 hours a day, 365 days a year, dramatically increasing the number of experiments you run and the amount of data you collect.

Increase your efficiency and publish more papers with an OptistatDry. 

Hazards of liquid cryogens

 The hazards of using liquid cryogens are well known and include:

  • Asphyxiation due to the displacement of air
  • Fire risk due to condensation of liquid oxygen
  • Risk of explosion due to blockage of outlets from cryogenic containers
  • Cold burns due to touching cold metal or direct contact with the liquid

These hazards can have fatal consequences, so it is important that all users of liquid cryogens make themselves aware of their local safety regulations. The OptistatDry does not use any liquid cryogens, so the hazards above do not apply to this product.

Costs of providing the facilities and safety training for liquid cryogens

The costs of running large liquefaction plant to provide an institute with liquid cryogens are high. These include the costs of running and maintaining the liquefier, and the costs of the fully trained staff to operate it.  

Less well documented are the costs and inconvenience of using liquid cryogens. Liquid cryogen storage dewars take up a large amount of floor space in the laboratory reducing the amount of space for experiments. Personal protection equipment and oxygen monitors are expensive and can be cumbersome. Ensuring everyone in the lab is trained and aware of all the relevant safety procedures can take up valuable time and limit the number of people who are able to work on these experiments. 

The OptistatDry does not use liquid cryogens so all of these costs and constraints no longer apply.

OptistatDry TLEX model - brochure and other downloads

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