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LT3-WMX-1

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LT3-WMX-1SS System
LT3-WMX-1SS Disassembled

The LT3-WMX-1SS offers a wide range of flexibility at a reasonable cost.

Click here to download the LT3-WMX-1SS data sheet (PDF).

This high performance system offers an all stainless steel constructed vacuum shroud along with a welded stainless steel instrumentation skirt. This system is capable of achieving vacuum levels of 10-7 Torr with an appropriate vacuum system. The nickel plated copper radiation shield provides low emissivity which is ideal for low temperature experiments.

Click here to see more Advanced Research Systems cryostats for Mössbauer Spectroscopy.

Applications
  • Optical- UV, VIS, IR
  • Raman
  • FTIR
  • Photoluminescense
  • Deep level transient spectroscopy (DLTS)
  • Photoinduced current transient spectroscopy (PICTS)
  • Electro-optical
  • Magneto-optical
  • Resistivity
  • Hall experiments
  • Diamond anvil cell
  • Dual inline package (DIP)
  • Liquid samples
  • Non-optical
  • Thermal
  • Electrical and magnetic susceptibility
  • Matrix isolation
  • Mossbauer
  • Low vibration
Features
  • Liquid helium flow
  • Welded stainless steel construction
  • Large, clear view optical windows (1.25 in.)
  • Large sample viewing angle for optical collection (F/0.8)
  • Matrix heat exchanger
  • Co-axial shield flow
  • 4 K liquid helium operation (1.7 K with pumping)
  • 0.7 LL/hr liquid helium consumption at 4.2 K
  • Liquid nitrogen compatible (77 K operation)
  • Precision flow control
  • Fully customizable
Typical Configuration
  • Cold head (LT3-WMX-1)
  • Co-axial shield flow liquid helium transfer line
  • Stainless steel instrumentation skirt
  • Dewar adapter
  • Flow meter panel for helium flow control and optimization
  • Welded stainless steel vacuum shroud for optical and electrical experiments (WMX-1SS)
  • Nickel plated OFHC copper radiation shield
  • 2 high purity quartz windows
  • Instrumentation for temperature measurement and control:
    • 10 pin hermetic feedthrough
    • 36 ohm thermofoil heater
    • Silicon diode sensor curve matched to (± 0.5 K) for control
    • Calibrated silicon diode sensor (±12 mK) with 4 in. free length for accurate sample measurement
  • Wiring for electrical experiments:
    • 10 pin hermetic feedthrough
    • 4 copper wires
  • Sample holder for optical and electrical experiments
  • Temperature controller
Options and Upgrades
  • High flow transfer line
  • 450 K high temperature interface
  • 800 K high temperature interface
  • Custom temperature sensor configuration (please contact our sales staff)
  • Custom wiring configurations (please contact our sales staff)
  • Sample holder upgrades (custom sample holders available)
  • Window material upgrades (custom materials available)

The ARS Advantage

Matrix Heat Exchanger
The Matrix Heat Exchanger is Imbedded in the Cold Tip of the Helitran Flow Cryostat

The Helitran® incorporates an extended surface tip heat exchanger (Matrix Heat Exchanger)  which provides efficient heat transfer between the helium and the sample mount.  The liquid helium flows through this heat exchanger and as the latent heat of  vaporization cools the sample mount,  the liquid evaporates. The gas continues to flow through the exchanger, providing additional cooling by capturing the enthalpy of the gas. If the flow is optimized the helium gas will exit the Matrix Heat Exchanger at a temperature equal to the sample temperature.

Without an extended surface cryostat tip heat exchanger, the consumption of helium during initial cooldown is 40 times higher from 300 K (room temperature) to 4.2 K, and 14 times higher when cooling from 77 K to 4.2 K.

Co-axial Shield Flow
A Schematic Representation of the Coaxial Shield Flow Transferline

Conventional helium flow cryostats utilize a capillary tube in a vacuum jacket with super insulation to reduce the radiant heat load.  However as the helium absorbs radiant heat, the liquid is vaporized and forms bubbles of gas which have a larger volume than the liquid, thus forming a temporary block to the flow of the liquid. This is called “vapor binding.”  At the delivery end of the transfer line this results in the liquid/gas mixture being delivered in spurts, with accompanying pressure and temperature cycling.

The coaxial flow transfer line incorporates a shield flow surrounding the tip flow for the entire length of the transfer line. The entrance to the coaxial shield flow tube is provided with a nozzle which results in a pressure and corresponding temperature drop in the shield flow. This cools the tip flow in the center tube, which prevents boiling and gas bubble formation in the helium, even at very low flow rates.  The helium is delivered at the sample end with the desired temperature stability and low vibrations.

High Temperature Options
800K Interface Manufactured by ARS

Our high temperature interfaces use a unique combination of mechanical and thermodynamic properties to create a high temperature thermal disconnect between the cold head and the sample space. This allows for heating of the sample space far in excess of the maximum 355 K temperature of our cryocoolers.

450 K The Easy Way

Our 450 K interface is a simple semi-permanent addition to the cold tip that expands the upper sample temperature range by 95 K utilizing most of the same instrumentation as our standard cryocoolers.

800 K - Pouring on the Heat

Our specially designed 800 K interface goes beyond the standard techniques to provide a unique system that maximizes thermal conduction at low temperatures while minimizing heat transfer at high temperatures. Beyond the safe operating temperature of silicon diodes, the standard sensors are replaced with E-type thermocouples and platinum RTDs.

Wired the Right Way - Your Way
Thermally Anchored Sensor Wiring on the DE-202 Cold Tip

Our technicians painstakingly wrap each cold head for optimum thermal anchoring. We offer you the choice of a variety of wiring options, from our standard offerings of single strand copper and low noise coaxial wiring packages to any number of custom wiring configurations.

Typical instrumentation for temperature measurement and control include one 36 ohm thermofoil heater, one curve matched silicon diode for rough temperature control, and one free length calibrated diode for direct attachment to the sample or sample holder for accurate temperature measurement. Silicon diode sensors are favored heavily for most standard applications because of their low cost, durability, and stability, but we do offer a wide variety of other sensors for different applications such as Cernox sensors for high magnetic fields, E-type thermocouples for 4 K-800 K measurements, and platinum RTDs for accurate high temperature measurements.

Our wide selection of wiring and instrumentation is matched by an equally wide selection of temperature controllers from Cryocon, Lake Shore, and Scientific Instruments.

Specialized Optics For All Applications
DMX-1AL Optical Block

Window Materials for All Transmission Ranges

High purity quartz is the standard window material for most of our optical cryostats, but we have a wide variety of other window materials available, from near IR materials like CaF2 and KBr to far IR and terrahertz like Ultra High Molecular Wright Polyethylene and Picarin, to Kapton, Mylar and beryllium for x-ray experiments. If you don't see the window material you're looking for, please contact one of our sales representatives.

Optimized for Weak Signal Collection with Minimum Heat Load

The tiered optical access of the 1.25" clear view vacuum shroud window and radiation shield optical ports allows for a large cone of optical access (F/# = 0.8 and at the same time limits the area of exposure to 300 K thermal radiation.

Low Stress Window Mounts

Our window ports are designed to gently cradle the window material, creating a low stress seal that limits optical distortions.

A Sample Holder for Every Measurement
SHOE-1C Sample Holder for Optical and Electrical Experiments

Whether the measurement is optical or electrical in nature, the sample large or small, we have a sample holder for almost any measurement. The LT3-WMX-1 can accept all but our largest sample holders. Like all of our cold fingers, the LT3 has a 1/4-28 threaded hole on the cold tip to mount the sample holder. So even if you do not find what you need from our wide variety of sample holders there is always the option of attaching a custom sample holder.

WMX-1 Specifications

Cooling Technology-
  LT3 Open Cycle Cryocooler
  Refrigeration Type Liquid Helium Flow
  Liquid Cryogen Usage Helium, Liquid Nitrogen Compatible
Temperature*-
  LT3 < 4.2 K - 450 K ( < 2 K with pumping )
  With 800 K Interface (Base Temp + 2 K) - 700 K
  With 450 K Interface (Base Temp + 2 K) - 450 K
  Stability < 2 mK (with properly tuned cryogen flow)
  *Based on bare cold head with a closed radiation shield, and no additional sources of experimental or parasitic heat load.
Sample space-
  Diameter 36 mm (1.43 in)
  Height 39 mm (1.53 in)
  Sample Holder Attachment 1/4-28 screw
  Sample Holder View our Sample Holder Collection
Optical Access-
  Window Ports 5 - 90° Apart
  Diameter 41 mm (1.63 in)
  Clear view 32 mm (1.25 in)
  #/F 0.8
  Window Material View our Wide Selection of Window Materials
Temperature Instrumentation and Control (Standard)-
  Heater 1 - 36ohm Thermofoil Heater Anchored on Cold Tip
  Control Sensor 1 - Curve Matched Silicon Diode
  Sample Sensor 1 - Calibrated Silicon Diode
  Custom Instrumentation Contact ARS for available Options
Instrumentation Access-
  Instrumentation Skirt Welded, Stainless Steel
  Pump out Port 1 - NW-25
  Instrumentation Ports 2
  Instrumentation Wiring Contact our sales staff for wiring options
Vacuum Shroud-
  Material Welded Stainless Steel
  Length 338 mm (7.75 in)
  Diameter 79 mm (3.12 in) (at the sample space)
  Width 56 mm (2.21 in) (at the sample space)
Radiation Shield-
  Material OFHC Copper, Nickel Plated
  Attachment Threaded
  Optical Access 0, 2, 4, or 5(customer specified)
Cryostat Footprint-
  Overall Length 383 mm (15 in)
  Rotational clearance 122 mm (4.8 in) with "G" configuration

Liquid Helium Flow Cryostat Specifications

Cryostat Model LT3
   Cryogen Liquid helium Liquid nitrogen
   Base Temperature 4.2 K < 2 K with pumping 77 K
   Nominal Helium Consumption at 4.2 K 0.7 LL/hr  
    Cooling Capacity- 0.7 LL/hr 2 LL/hr  
  4.2 K 0.5 W 1.5 W  
  20 K 3.0 W 8.0 W  
  50 K 7 W 20 W  
    Maximum Temperature 450K with cold gas flow through transfer line  
    Cooldown Time- 4.2 K 20 min  
    Weight 0.9 kg (2 lbs)
LT3-WMX-1SS Drawing

LT3-WMX-1SS
Full Cryostat

Click on the images for full size.