LFA L51 - Where Thermal Analysis Meets Innovation
The LINSEIS LFA L51 is a versatile Light Flash Analyzer for high-precision measurement of thermal diffusivity, thermal conductivity and specific heat capacity. It is ideal for analyzing solids, powders, pastes and liquids in a wide range of industrial applications – such as electronic packaging, heat exchangers, thermal insulation and reactor cooling. With a broad temperature range of –100 °C to 1250 °C , the LFA L51 enables fast, non-contact and non-destructive measurements with minimal sample preparation and high accuracy.
This absolute measurement method requires no calibration and complies with international standards such as ASTM E-1461, DIN EN 821-2 and DIN 30905. The system is equipped with user-exchangeable InSb or MCT detectors (LN₂-cooled) and can optionally be operated with automatic LN₂ refilling. Operation under vacuum or in inert gas atmosphere is possible thanks to an optional gas dosing system – for maximum flexibility in modern thermal analysis.
Unique features
Software Improvements
- New LINSEIS LiEAP software: Our completely new software platform is now even more closely aligned with the needs of our customers, so you are always informed of the current status and receive support whenever needed.
- Automatic updates and new features: Our software regularly receives automatic updates that not only improve security but also continuously provide new features.
- Lex Bus Plug & Play: Our latest hardware interface, Lex Bus, revolutionizes data communication within our systems. Lex Bus enables seamless and efficient integration of new hardware and software tools.
- Improved furnace control: Our new and further improved furnace control offers more precise temperature regulation, leading to better measurement results and higher throughput through improved temperature sequencing tailored to your needs and requirements.
- Predictive maintenance and problem detection: By using intelligent components and accessories, our predictive maintenance approach detects problems and signs of wear before they can cause damage, keeping your instrument in top condition.
New and improved light guide system
Delivers more energy to the sample and pushes the boundaries further. The innovative light guide system significantly extends the measurement range by maximizing the power reaching the sample, delivering signals up to three times stronger. This is especially beneficial for samples with lower thermal conductivity or greater thickness, which can now be measured more easily and accurately.
Linseis Lab Link
With Linseis Lab Link, we offer an integrated solution for uncertainties in measurement results. Direct access to our application experts via the software gives you guidance on the correct measurement procedure and on evaluating results. This direct communication ensures optimal results and maximizes the efficiency of your measurements for precise analyses and research work, as well as a smooth workflow.
Design Improvements
The new instrument design features an elegant aluminum housing that is both robust and visually appealing. The LED status bar provides user-friendly visualization of important information. A touch panel enables intuitive operation and contributes to a modern user experience that combines comfort and functionality. The new instrument design places a strong focus on ergonomic operation.
PLH Upgrade
LFA L51 instruments can be upgraded with the PLH (Periodic Laser Heating) option. This patented 2-in-1 solution offers two measurement techniques in a single instrument, maximizing the range of applications and enabling the analysis of samples ranging in thickness from µm to mm.
PLH technology was specifically developed and optimized for characterizing thin film samples with unprecedented accuracy. It covers a measurement range of sample thicknesses from 10 μm to 500 μm and a thermal diffusivity range of 0.01 to 2000 mm²/s.
The PLH L53 option is suitable for a wide variety of materials and therefore for the following applications:
- Heat spreading materials such as graphite foils and thin copper foils,
- Semiconductors with complex thermal properties,
- Metals requiring precise diffusivity measurements,
- Ceramics and polymers used in advanced material systems.
Analysis of Anisotropy and Inhomogeneity
With its advanced mapping capabilities, the PLH system enables spatially resolved measurement of a sample’s thermal conductivity. This feature is particularly valuable for identifying anisotropies (directional differences in thermal behavior) and inhomogeneities (material inconsistencies). By scanning multiple areas, users gain a comprehensive understanding of the thermal properties of thin films, ensuring optimized material performance for demanding applications.
Applications and Industry Focus
Typical applications include the analysis of free-standing films and membranes, which are becoming increasingly important in the battery and hydrogen industries. The ability to accurately measure the heat transport properties of these materials is crucial for improving energy efficiency, thermal management, and overall system performance.
Key Features at a Glance
- Anisotropy analysis: Seamlessly combines through-plane and in-plane measurements.
- Versatile material compatibility: Suitable for semiconductors, metals, ceramics and polymers.
- Mapping capability: Enables precise spatial analysis of anisotropies and inhomogeneities within the sample.
- High measurement accuracy: Covers a broad range of sample thicknesses and thermal conductivity values.
Highlights
Wide temperature range:
-100°C to 1250°C
High measuring accuracy
and repeatability
Modular design for
flexible customization
Fastest measuring times thanks
to laser/light flash technology
User-friendly software
for comprehensive data analysis
Suitable for solids,
layers and liquids
Key features
New Electronics
- Improved amplifier electronics: The improved electronics enhance the signal-to-noise ratio (SNR) and 16-bit resolution, ensuring precise and reproducible measurements for thin or conductive samples.
- Higher data acquisition rate: An acquisition rate of 2.5 MHz enables precise analysis of fast-conducting and thin materials, capturing detailed data in a short time.
- Improved communication: Linseis instruments can be operated via USB or Ethernet, either as standalone units or within a larger network.
Optimized Low-Temperature Furnace
The newly introduced signal-optimized low-temperature furnace ensures gradient-free, highly accurate measurements at lower temperatures and higher speed for increased throughput.
Gradient-Free Heating Zone
The furnace’s temperature control is optimized by a gradient-free heating zone. This design ensures that the entire sample is heated evenly, resulting in improved measurement reproducibility, which is crucial for accurate thermal conductivity results.
Full Sample Illumination
The LFA L51 ensures full illumination of samples up to 25.4 mm in diameter, avoiding a radial temperature gradient in the sample. This results in improved reproducibility and more consistent results across a wide range of sample sizes.
Questions? Just give us a call!
+49 (0) 9287/880 0
Thursday from 8 am to 4 pm
and Friday from 8 am to 12 pm.
We are here for you!
Specifications
Temperature range: –100 °C to 1250 °C
Thermal conductivity: 0.1 to 4000 W/(m·K)
Genauigkeit der Wärmeleitfähigkeit: ±2,4 %
Discover our powerful LFA – designed for fast and reliable thermal conductivity analysis:
- Flash source: Software-controlled light flash (15 J/pulse, 50–2000 µs pulse width)
- Detector options: InSb or MCT (LN₂-cooled)
- Vacuum capability: Up to 10⁻⁵ mbar
- Flexible sample handling: Solids, powders, pastes, laminates, thin films
- High-speed data acquisition: 2.5 MHz
Method
Light Flash Analysis
The The Light Flash Method (LFA) is a fast, non-contact technique for determining the Thermal Conductivity, specific heat and Thermal conductivity of solids, powders and pastes. A short energy pulse heats the back of the sample, and the resulting temperature rise on the front is recorded over time using a high-speed infrared detector recorded over time.
The temperature rise curve indicates how quickly heat spreads through the sample. From this data, the thermal diffusivity is calculated. If the specific heat and density of the material are known, the thermal conductivity can also be determined.
LFA is a non-destructive and highly precise method widely used in materials research, electronics, aerospace and energy applications. Key advantages include short measurement times, minimal sample preparation effort, and the ability to examine a wide range of materials – all with high repeatability and under controlled atmospheres.
Measurement Principle
In an LFA measurement, the sample is heated to a defined temperature in a furnace or micro-heater. A programmable light pulse – typically generated by a laser or a xenon flash lamp – is directed at the bottom side of the sample. This causes an instantaneous heating of the back surface, resulting in a temperature rise on the surface.
This temperature change is recorded over time using a sensitive IR detector. From the resulting temperature-time curve, the half-time of the temperature rise and the sample thickness are used to calculate the thermal diffusivity. With additional knowledge of the specific heat and density, the thermal conductivity can be derived.
This method delivers accurate results with short measurement times, supports a wide temperature range, and enables measurements under vacuum or controlled gas atmospheres.
Measured Quantities
- Thermal diffusivity (α [mm²/s])
- Specific heat capacity (Cp [J/g·K])
- Thermal conductivity (λ [W/m·K]) (calculated via α · Cp · ρ)
- Temperature-dependent thermal properties
- Repeatability and accuracy data
Supported Methods and Features
- Multi-sample measurement (up to 18 samples)
- Thin film analysis (with PLH module)
- Isothermal and temperature-dependent measurements
- Analysis of anisotropic materials
- Measurement of powders, pastes, solids and laminates
- Measurement under controlled atmospheres (inert, reducing, oxidizing)
- Vacuum measurements (up to 10⁻⁵ mbar)
- High-speed data acquisition for fast thermal events
A Step Ahead with the LFA L51 – Flexible Solutions for Every Thermal Challenge
PLH L53 - Periodic Laser Heating
LFA L52 Nuclear
Questions? Just give us a call!
+49 (0) 9287/880 0
Thursday from 8 am to 4 pm
and Friday from 8 am to 12 pm.
We are here for you!
LFA L51 uncovered – how it works, where it fits, what it offers
Measurement Concept
The sample is positioned either on a sample robot surrounded by a furnace (LFA L51 LT/500/1000) or in one of five micro-heating elements located on a movable linear stage (LFA L51 1250). For the measurement, the furnace is held at a predetermined temperature, and a programmable energy pulse is directed at the back of the sample, causing the temperature at the sample surface to rise. This resulting temperature increase at the sample surface is measured with a highly sensitive, high-speed infrared (IR) detector. From the temperature-time data, both thermal conductivity and specific heat can be determined. If the density (ρ) is known, thermal conductivity can be calculated as follows:
Vision Control
Measurement Principle
In a flash system, signal quality depends on the amount of radiation from the sample that reaches the surface of the infrared detector. Typically, the active area of the detector is limited compared to the sample diameter (3 mm to 25.4 mm) (e.g., 2 x 2 mm²). For this reason, an optimized arrangement of IR detector, lens, and sample is used to improve the imaged sample surface. The measurement spot on the sample should be as large as possible without extending beyond the sample. If the spot overshoots the sample edge, this can lead to measurement artifacts or additional signal noise. Vision Control ensures the best signal quality for all sample sizes. This optimization guarantees excellent signal quality for both large and small samples.
Vision Control
The “Vision Control” option ensures a perfect detection point for different sample geometries. This enables ideal alignment so that the sample surface is imaged sharply and precisely onto the active sensor area.*
*Not available in all configurations and countries.
High-speed infrared furnace or micro-heater for unmatched sample throughput
The LFA L51 can be equipped with either a high-speed infrared furnace (LFA L51 500/1000), an advanced micro-heating element (LFA L51 1250), or a low-temperature resistance furnace (LFA L51 LT), enabling exceptionally fast heating and cooling rates. This rapid temperature adjustment minimizes downtime, saves valuable time, and enables high sample throughput for increased laboratory productivity. With this technology, numerous samples can be analyzed in a short time, which is especially beneficial for time-critical applications. The infrared and micro-heating technology also ensures precise and uniform temperature control, delivering reliable and accurate measurement results.
Because Time Matters
Comparison of time to reach temperature stability.
A fast IR micro-heating furnace reaches the set temperature significantly faster and delivers excellent isothermal temperature stability.
The comparison of cooling times for the IR furnace, micro-heating element, and MoSi resistance heating element clearly shows the advantage of short cooling times. This enables multiple measurements in rapid succession and improves sample throughput. The IR furnace cools from 1000 °C to 30 °C in 105 minutes, while the micro-heating element requires only about 26.5 minutes. Even when cooling from 1250 °C, it stays under 30 minutes. By comparison, the MoSi heating element cools from 1560 °C to 19 °C in about 147 minutes.
LFA L51 furnaces
LFA L51 500
This model offers cost-effective measurements of thermal conductivity, diffusivity, and specific heat for up to 6 samples, with a temperature range from RT to 500 °C and fast IR detection for precise analysis. This makes it ideal for applications involving polymers or low-melting-point materials.
LFA L51 1000
A modular instrument for measuring thermal diffusivity and thermal conductivity, supporting temperatures from RT to 1000 °C, optimized for fast measurement cycles and high flexibility, and perfectly suited for analyzing ceramics and metals.
LFA L51 1250
Provides precise measurements at temperatures up to 1250 °C with fast heating and cooling, making it well suited for thermal analysis applications involving ceramics and metals.
LFA L51 LT
The low-temperature version delivers precise measurements from
-100 °C to 500 °C for various low-temperature applications.
Sample carriers and holders
Various sample holder types enable measurement of a wide range of sample sizes from 3 to 25.4 mm in solid, liquid, powder, or paste form. Sample holders for phase change materials are also available. The Linseis sample robot can measure up to 6 samples simultaneously, with up to 18 samples possible on request. Graphite, SiC, aluminum oxide, or various metals are available as sample holder materials.
Sample Carriers
Sample Holders
Model selection
Supported Model Selection
The software allows the selection of various evaluation models. To assist the user in making a selection, the goodness of fit of all models can be easily displayed, ensuring ease of use and maximum accuracy.
Empirical data from customers and Linseis application labs worldwide show that the combined Dusza model is the most universally applicable and typically provides the best agreement between measured data and model across a wide range of materials.
Combined Dusza Model – A unique combined solution for simultaneously correcting heat losses and finite pulse effects with the laser flash method
The universal combined model, based on the proven method of Dusza, enables reliable evaluation of laser flash data by simultaneously correcting for heat losses, finite pulse effects, and non-adiabatic conditions. Thanks to nonlinear parameter estimation, no manual model selection is required, saving time and avoiding user error. The method has been tested on over 100 samples and consistently delivers accurate, top-quality results. The example with an Inconel sample clearly shows that the combined model offers the best fit and highest precision compared to conventional approaches.
Modified Combination Model / Special Model for Translucent Samples
As shown in the graph, the temperature rise caused by the induced energy pulse in translucent samples leads to an immediate increase in the detector signal. This initial signal must be accounted for and corrected, as it skews the measurement result toward an apparently higher thermal diffusivity. Until now, existing models have not been able to adequately explain this phenomenon of instantaneous temperature rise. Our unique combined model allows the sample data to be corrected, providing an adjusted fit that leads to significantly improved measurement results.
McMasters model for porous samples
The McMasters model is a specialized tool designed to analyze heat transfer in porous materials with precision and flexibility.
Key features:
- One-dimensional heat transfer model for accurate analysis.
- Includes the finite penetration depth of the initial pulse as an important fitting parameter.
- Accounts for heat losses at the front and back of the sample.
This advanced model, based on the work of McMasters et al.*, ensures reliable and detailed results,
making it an indispensable option for complex thermal investigations.
* McMasters, Robert L. et al. “Accounting for Penetration of Laser Heating in Flash Thermal Diffusivity Experiments.” ASME. J.
Heat transfer (1999): 121(1): 15-21.
How much does an LFA L51 cost?
The price of an LFA L51 system depends on the chosen configuration and additional options, such as temperature range, detector type, automation features, or special sample holders. Since each system can be individually tailored to your specific application requirements, costs can vary significantly.
For an exact quote, please use our contact form to let us know your requirements – we will be happy to provide you with a customized quote.
What is the delivery time for an LFA L51?
The delivery time for an LFA L51 depends significantly on the selected options and the desired configuration. Additional features such as extended temperature ranges, special detectors, automation, or custom adaptations can increase production and preparation effort, thereby extending the delivery time.
Please contact us via our contact form to receive a precise delivery time estimate based on your individual requirements.
Software
Making values visible and comparable
ALL-NEW LiEAP Software
The newly developed LiEAP software includes an AI-based assistance function that minimizes operating errors and reduces measurement uncertainties. Furthermore, the software supports various unique models, including the Dusza model, which can process transparent, porous, liquid, and powder samples as well as multi-layer systems.
Key Features
- Fully compatible MS® Windows™ software
- Data security in case of power failure
- Safety features (thermocouple break protection, power failure, etc.)
- Online and offline evaluation of the current measurement
- Curve comparison
- Storage and export of evaluations
- Export and import of data in ASCII format
- Data export to MS Excel
- Multi-method analysis (DIL, STA, DSC, HCS, LSR, LZT, LFA)
- Programmable gas control
- NEW workflow
Determination of specific heat (Cp) by comparative methods
To calculate the specific heat capacity, the maximum temperature rise of the sample is compared with the maximum temperature rise of a reference sample. Both the unknown sample and the reference sample are measured under the same conditions in a single run using the sample robot. Thus, it can be assumed that the energy of the laser pulse and the sensitivity of the infrared detector are the same for both measurements.
Pulse Detection
To improve the accuracy of the Cp measurement, it is essential to measure the energy of the pulse and the sensitivity of the detector instead of assuming them to be constant.
Therefore, the updated LFA L51 offers the possibility to record the pulse shape, detect the pulse shape, and perform an energy correction in the fully automatic measurement cycle. This leads to a highly accurate determination of the specific heat capacity in comparative measurement mode with a known reference material.
Evaluation Software
- Automatic or manual input of related measure- ment data: such as density and specific heat
- Universal combined evaluation model for data evaluation
- Special models for translucent or porous samples
Evaluation Models
- Dusza combined model
- NEW McMasters model (for porous samples)
- 2-/3-layer models
- Parker
- Cowan 5 and 10
- Azumi
- Clark-Taylor
- Degiovanni
- Finite pulse correction
- Heat loss correction
- Baseline correction
- Multilayer model
- Determination of contact resistance
- Correction for translucent samples
Measuring software
- Easy and user-friendly data input for tempera- ture segments, gases etc.
- Controllable sample robot
- Software automatically displays corrected measurements after the energy pulse
- Fully automated measurement procedure for multi sample measurements
- Costumer support
- Easy mode for efficent and fast measurements
- Expert mode for maximum individualisation
- Service model monitors the device mode and provides feedback
Application
Ceramics & Glass
Glass and ceramics are indispensable materials in both traditional and high-tech applications. From household items to sophisticated components in electronics, aerospace, and medical technology, their unique mechanical, thermal, and chemical properties enable versatile use under demanding conditions.
Thermal analysis methods play a crucial role in material development and process optimization. They provide precise insights into thermal conductivity, heat capacity, thermal expansion, and sintering behavior. This allows manufacturers to optimize composition, improve energy efficiency, and ensure product performance for a wide range of glass and ceramic materials – including technical ceramics, smart surfaces, and fiber-reinforced composites.
Application example: Thermal conductivity, thermal diffusivity and specific heat capacity of glass ceramics
BCR 724, a standard glass ceramic, was measured with the LFA L51 500 / 1000. For this purpose, a small disk with a thickness of 1 mm and a diameter of 25.4 mm was cut from a plate of the bulk material and coated with graphite for the measurement. The LFA L51 provides thermal diffusivity as a direct function of temperature. The Cp data were determined comparatively by measuring a known ceramic standard under the same conditions in a second sample position of the same sample holder. From this, the thermal conductivity was calculated as the product of density, specific heat, and thermal diffusivity. The result shows a slightly decreasing thermal diffusivity and thermal conductivity, while the Cp value increases with rising temperature.
Application example: Thermal conductivity of glass ceramic
Pyroceram, a glass-ceramic brand from Corning used as a standard material in various applications, was measured with the LFA L51 1250 to demonstrate the reproducibility of thermal conductivity values. A total of 18 measurements were performed with 18 samples cut from one block. Each sample was measured separately, and the result shows a scatter in the range of +/- 1% in a temperature range up to 1160 °C.
Research, Development and Academia
New materials play a crucial role in technological innovations – from lightweight composites in aerospace to high-performance ceramics and semiconductors. Their development requires detailed knowledge of thermophysical properties such as thermal diffusivity, thermal conductivity and specific heat capacity.
LINSEIS LFA systems enable fast, non-destructive, and precise measurement of these important parameters. This makes them indispensable tools in materials research and development, particularly for polymers, ceramics, hybrid materials, and high-temperature alloys. With accurate LFA data, researchers can optimize heat flow, improve performance under thermal stress, and support the development of safer, more efficient, and more sustainable materials.
Application example: Thermal conductivity of graphite
A graphite sample was investigated with the LFA L51. Thermal conductivity was determined directly at several temperatures between RT and 1000 °C. Specific heat capacity was determined using a known graphite standard in a second sample position as a reference in the same measurement. The product of diffusivity, specific heat, and density yields the corresponding thermal conductivity. The result shows a typically linear decreasing thermal conductivity and a thermal diffusivity that reaches a plateau above 500 °C. The Cp increases slightly with increasing temperature.
Polymers
Polymers are used in countless applications – from packaging and automotive parts to aerospace and medical devices. To ensure reliable performance, it is essential to understand their thermal conductivity, specific heat and thermal diffusivity, especially when it comes to thermal insulation, cooling behavior or aging resistance.
LINSEIS LFA systems enable accurate, non-destructive analysis of these key properties for all polymer types – including thermoplastics, thermosets and elastomers. Whether for product development, quality control, or material comparison: LFA measurements contribute to the optimization of processing conditions and support the selection of the right material for every application.
Application example: Thermal conductivity of polymers
PTFE is a versatile material widely used in industries such as chemical processing and petrochemistry for applications like vessel linings, seals, gaskets, and washers due to its chemical inertness and corrosion resistance. In this study, a PTFE sample was measured with the LFA L51 500 at up to 150 °C in an inert atmosphere. Thermal conductivity was derived from specific heat and density change data recorded with a dilatometer and DSC. Thermal conductivity remains stable over the entire temperature range, except for the region around 30 °C, where a solid-to-solid phase transition occurs.
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