MMR Technologies has been the professional’s resource for modular, flexible, cost-effective benchtop systems and components.
Inventor of the micro-miniature refrigerator, MMR supplies the leading-edge tools for variable-temperature solid-state characterization — for your materials research, biological and medical research and more.

Seebeck Measurement Systems

MMR’s Seebeck Measurement System allows users to make automatic measurements of the temperature-dependent Seebeck potential of metals, semiconductors and other electrically conductive samples over a temperature range from 70 K to 730 K, and from 300K to 730K. Sample mounting is simple permitting rapid interchange of samples. The Seebeck system is compatible with a variety of computers through a USB or RS-232 interface. The MMR Programmable Seebeck Measurement System includes the SB000 Digital Seebeck Controller, the K2000 Digital Temperature Controller, the Seebeck Thermal Stage and accessories, and MMR Technologies Integrated Software Suite.

The Seebeck Thermal Stage includes two pairs of thermocouples. One pair is formed of junctions of copper and a reference material of known Seebeck emf. The other pair is formed of junctions of copper and the material whose Seebeck emf is to be determined. The system uses a sophisticated parametric double reference measurement technique developed at MMR Technologies, that yields precise, highly reproducible results, even with difficult samples.

Detail of Seebeck  Thermal Stage

BLACK: Studied Material

RED: Reference Material

MMR Seebeck stages cover
a wide operating range

All alumina stage allows measurements at temperatures above 400K.

Polyimide stage allows measurements
at temperatures below 400K.

   Features

  • All new Digital Temperature and Seebeck Controllers!
  • Maximum Operating Temperature: 70K to 730K
  • Highly accurate and highly reproducible Seebeck Coefficient measurements – 50 nV
  • Mismatch of Gains of reference and test channels: <0.1%
  • Minimum Heater Step Size: 0.1 mW
  • Automatic operation in a single step against an internal reference material.
  • Ease of measurement of samples ranging from metals to thin films.
  • Number of Readings Automatically Averaged: Up to 128
  • Stand alone Seebeck Experiments at ambient temperature
  • Full Software Suite provided for all measurements
  • Sample Length: >2 mm and <10 mm
  • Power available to heat the sample: 0.1 mWatt to 1 Watt
  • Power Input: 110 V, 60 Hz and 220 V, 50 Hz

 

Hall Measurement System

MMR’s Variable Temperature Hall System (VTHS) allows the user to make automatic measurements of resistivity, mobility and carrier concentration of a wide range of samples using the Van der Pauw method over a temperature range from 70K to 730K. Sample mounting is simple and allows rapid interchange of samples. The VTHS Hall Measurement Controller, the H5000, is compatible with a variety of computers through an USB or RS-232 interface. MMR’s Benchtop Electromagnet and Programmable Power Supply complement the VTHS. The system uses the VTHS Dewar described below.

Features

  • Operating Temperature: 70 K to 730 K
  • Guarded Triax Leads
  • H5000 interfaces with MMR’s Low Temperature Dewar
  • H5000 interfaces with MMR’s Programmable Temperature Controller
  • H5000 interfaces with two different MMR electromagnets, allowing maximum flexibility in sample analysis.
  • Hall magnetometer in Dewar included in system
  • Full software provided for all measurements
  • Power Input: 110 V, 60 Hz and 220 V, 50 Hz
  • H5000 Weight: 12 lb
  • H5000 Dimensions: 3.5″ x 8.5″ x 14″

Variable Temperature Hall Dewar

The VTHS Dewar is a low-profile Dewar designed to fit between the poles of a magnet to enable measurements to be made of the resistivity, Hall mobility and other properties of materials over a wide range of temperatures. Guarded triax leads provide electrical input to the sample via similarly guarded leads on a Kapton Harness to the sample on the cold stage. A Hall sensor immediately adjacent to the sample allows measurement of the magnetic field at the sample location.

 

In addition to the refrigerator and vacuum chamber, a temperature controller is needed, either manual or programmable; a source of dry nitrogen (99.998% purity); a filter dryer; and a vacuum pump capable of maintaining a vacuum <5 mTorr in the chamber. Other accessories that add to the convenience of operating the system are available from MMR.

 

Features

  • Operating Temperature: 70 K to 730 K
  • Temperature Stability: ± 0.1 K with MMR’s Programmable Controller
  • Temperature Response: 1 K/sec
  • Cooling Capacity: 250 mW at 85 K with nitrogen; 500 mW with Ar at 90 K
  • Cold Pad Size: 14 mm x 10 mm
  • Standard Window Material: Fused silica
  • Optional Window Materials: Sapphire, Quartz.
  • Guarded triax leads to sample
  • Four sample leads for Van der Pauw measurements
  • Extra BNC lead for heater for Seebeck measurements
  • Simple sample mounting
  • Integral Hall sensor at sample site
  • Compatible with two different MMR electromagnets, allowing maximum flexibility in sample analysis
  • Dewar Dimensions: 6.0″ L x 2.5″ W x 0.75″ H at sample
  • Weight of Vacuum Chamber: 170 g (6 oz)

Liquid Nitrogen Generators -MMR                                                                                                                                                                                                                                   

Fotonika’s solution partner MMR offers unique, small scale, user friendly laboratory LN2 generators.                                                                                                                          

MAKE YOUR OWN LIQUID NITROGEN

The Elan2 family of liquid Nitrogen generators provide you with clean, reliable, on-demand liquid Nitrogen at a touch of a button by extracting N2 direct from the air around you. All that is needed is a well ventilated semi-clean environment and standard wall electricity to make your very own liquid Nitrogen directly in your office or laboratory. Because the liquid Nitrogen generated has not been handled by industrial equipment and transport trucks, it is very clean making it ideal for clean rooms and medical applications.

THE ELAN2 AUTO TRANSFER SYSTEM

The Elan2 Auto Transfer system has the capacity to produce 6L – 8L per day of liquid Nitrogen. Once produced, the liquid Nitrogen is stored in a 20L dewar (storage tank) safely attached to the side of the unit. Liquid withdrawal is made easy with a supplied transfer device.

These systems are suited for users with varying daily demands. Once the storage tank is full, the unit safely shuts down avoiding spills or overflow. In the event of a power outage the 20L storage tank and its contents are always available, meaning the user is never without liquid Nitrogen.

THE ELAN2 OFFICE STATION SYSTEM

The Elan2 Office Station produces and stores 1L of liquid Nitrogen internally, ideally suiting those with limited liquid Nitrogen needs.

Once the liquid Nitrogen is dispensed from the system, another 1L will be available 3-4Hrs later. Dispensing is made easy by a simple push of a button. Unlike the Auto Transfer station, liquid Nitrogen delivery is not possible in the event of a power outage. A RFID security system built into the portable flask ensures that no unsafe liquid Nitrogen removal is possible. A standby mode is available to safely shut the system down when not needed

Variable Temperature Micro Probe Systems

MMR’s Variable Temperature Micro Probe Systems, VTMP, (or Low Temperature Micro Probe Systems, LTMP) allow the user to probe devices mounted on the cold stage of a micro refrigerator. Each manipulator allows the corresponding probe to be positioned anywhere on a 10 mm x 12 mm sample to a precision of 50 microns. The chamber can be supplied with from one to seven probes, VTMP-1 to VTMP-7. The chamber in photos below is a five-probe system.

In addition to the refrigerator and vacuum chamber, a temperature controller is needed, either manual or programmable; a source of dry nitrogen (99.998% purity); a filter dryer; and vacuum pump capable of maintaining a vacuum <5 mTorr in the chamber. Other accessories that add to the convenience of operating the system are available from MMR.

VTMP Vacuum Chamber and Refrigerator

MMR’s Variable Temperature Micro Probe Vacuum Chamber houses the micro miniature refrigerator and micromanipulators that enable probing of devices mounted on the cold stage of the refrigerator. Each probe can be positioned anywhere on a 10 mm x 12 mm sample to a precision of 50 microns. MMR’s Micro Probe Vacuum Chamber can be supplied with from one to seven probes. The system photo shows a four-probe chamber. The drawing illustrates a seven-probe chamber.

Features

  • Operating Temperature: 70 K to 730 K
  • Temperature Stability: ± 0.1 K with MMR’s Programmable Controller
  • Temperature Response: 1 K/sec
  • Cooling Capacity: 250 mW at 85 K with nitrogen; 500 mW with Ar at 90 K
  • Cold Pad Size:14 mm x 10 mm
  • Standard Window Material: Fused Silica
  • Optional Window Material: Sapphire, Quartz
  • Maxiumum Sample Size: 10 mm x 12 mm
  • Probe Travel – X/Y/Z: 25 mm x 25 mm x 6 mm
  • Positioning Accuracy: better than 50 microns
  • Electrical: SMA connectors with outer shield insulated from VTMP case. Mini-coax connects SMA to probe.

Options

  • Vibration isolation table
  • Turbo pump for higher vacuum pressure
  • Customized probes, including fiber optic, for flexibility in experiments

General Purpose and Custom Cryo Coolers

For years MMR Technologies has been the leading provider of Closed Cycle Kleemenko Cryocoolers. These low-cost refrigerator systems use a single-stream, throttle-expansion cycle of a mixture of refrigerants and have been used over the past decade to provide stable, maintenance-free temperatures down to 85K.

Kleemenko coolers are closely related to Joule-Thomson coolers. In J-T cooling, compressed gases pass down a counter-current heat exchanger before being allowed to expand through a capillary or throttling valve. Cooling occurs upon expansion and the cool gas passes back up the heat exchanger, pre-cooling the incoming high-pressure gas. In the Kleemenko cycle it is not a gas that expands, but rather a mixture of gas and liquid. One or more liquid-vapor separators may be incorporated into the cycle so the expansion of the liquid can be used to pre-cool the vapor.

MMR General Purpose Cryo Coolers

MMR can provide customized Kleemenko cooler systems that will meet your specific instrumentation or OEM needs. These customized cooler systems come with a cold head that can be integrated into a variety of applications and instrumentation settings, such as ultra high vacuum. MMR’s coolers have been used to cool a wide range of technologies from HpGE detectors, FLIR sensors, low-noise amplifiers, and X-ray detectors. All coolers feature low vibration and electrical isolation making them perfect for sensitive instumentation. If removing cryogens from your experimental setup is of interest – we can help you determine the best set up to meet your cooling capacity and experimental setup.

Custom Vacuum Cryostats and Interfaces

On request MMR’s cryostats can be configured for your specific application or needs. Customizations include vacuum flange type, cold finger length, cold finger geometry and umbilical length. In some cases the cooler capacity can be optimized for a specific temperature range should your application require it.

                                             Variable Temperature

For applications requiring variable temperature, MMR’s GP Cooler Temperature Controller is a self contained add-on to cryostats providing stable temperatures from 85K to 550K. All temperature controllers include power measurements, temperature plotting and control software for automatic temperature profiles.With the ability to set temperature remotely via a computer or stand-alone, temperature control has never been so easy.

Cooler Specifications

  • Voltage: 115VAC 60hz or 220V 50hz
  • Power: 350-500W
  • Compressor Noise: 60dB at 3FT
  • Compressor Operating Temperature: 40F to 85F
  • Cooldown Time: <40minutes to 85K unloaded
  • Run time/Duty: 0-100%
  • Umbillical Length: 10FT (Customizable)
  • Compressor Dimensions: 13.5”x11”x11”
  • Compressor Weight: 36lbs
  • Cryostat Weight: 9lbs
  • Electrical Isolation: Yes