Section for Mineralogy, Petrology & Geochemistry

Language Selection

Breadcrumb Navigation


Fragmentation Lab


Dr. Bettina Scheu
Dr. Ulrich Küppers
Laboratory Phone: +49 89 2180 4661


  • 4 Shock Tube Apparatus (fragmentation bombs): rapid decompression experiments at RT – 850°C, 0.1 – 50 MPa
  • Surface Area Analyzer (Gemini 2375, Fa. Micromeritics): gas sorption with Ar / N2 at powders and zylinders (up to 25mm diameter, 40mm height)
  • Helium Pycometer (Accupyc 1330, Fa. Micromeritics): volume and density measurements
  • LaserDiffraction Particle Analyser (LS230, Fa. Beckman Coulter): analysis of particles sizes between 0.04 µm to 2000 µm
  • Rotational Evaporator with Waterbath B-480 (Fa. Büchi)

4 Shock Tube Apparatus (fragmentation bombs)

  • Large low pressure tank (3 m long, 0.4m wide) and several high pressure autoclaves, separated by a set of 1-3 rupture discs
  • Rapid decompression experiments using Argon gas to analyse fragmentation behaviour (threshold, speed, efficiency) at 20°C - 900°C and 0.1 - 50 MPa
  • Phreatic Explosion experiments with water saturated samples, P&T sensors installed in the range of 20°C – 400°C and 0.1 – 25 MPa.
  • Measurement of Particle ejection speed
  • Analysis of natural samples and magma analogues
  • Full recoverage of particles -> GSD
  • Pulse-decay permeability measurements
  • several sample sizes (mm):   19x50, 25x60, 60x60, 34x70
  • high-speed video recording from 50 to >50.000 fps

Description of facility:

The shock-tube devices are tailor-made and can be operated with a variety of set-ups to investigate aspects of fragmentation behaviour or natural and analogue material as: fragmentation threshold, fragmentation speed and permeability via a pulse-decay method. The shock-tubes operate from room temperature up to 900°C and at pressures between 1 bar (atmospheric) to 50 MPa applied pressure using by default argon gas for pressurization (pressurization by nitrogen or H2O vapour is also possible). Depending on the set-up, the experiment is monitored by a varying number of pressure and temperature sensors. The experimental pyroclasts are fully recoverable and thus allow determining the fragmentation efficiency.

fraglab-1 fraglab-2

(e.g. Spieler et al., EPSL, 2004)

fraglab-4 fraglab-5
fraglab-6 fraglab-7


Surface Area Analyzer (Gemini 2375, Fa. Micromeritics)

gas sorption with Ar / N2 at powders and cylinders (up to 25mm diameter, 40mm height)

The Gemini gas sorption device installed allows to measure powder and ash samples up to 25mm sized cylindrical samples (30mm in length). By default Argon gas is used. Typically a total surface area of 0.08-0.1 m²/g and specific surface area from 0.008 - 0.01 m²/g can be detected. The device determines single- and multpoint BET and Langmuir surface areas; total pore volume, and micropore analysis by the t-method can be obtained when operating with nitrogen gas fraglab-8


Helium Pycometer (Accupyc 1330, Fa. Micromeritics)

volume and density measurements

A Micrometric, fully automated helium pycnometer is installed in the FragLab. Maximum sample size is limited to 61mm in height and 40 mm in diameter. The pycnometer measures the volume (not accessible to helium gas) displaced by the sample, together with the sample mass, its density can be achieved. The connected porosity can be calculated knowing the geometric volume of the sample. Total and isolated porosity is determined by crushing the sample and measuring its powder density. fraglab-9


LaserDiffraction Particle Analyser (LS230, Fa. Beckman Coulter)

analysis of particles sizes between 0.04 µm to 2000 µm

The Laser Diffraction Particle Size Analyzer installed at FrabLab operates solely with wet samples (sample in water suspension). It measures particle size using the classic Mie theory of light scattering and Beckman Coulter exclusive PIDS technology (Polarization Intensity Differential Scattering), offering high resolution and reproducibility. These analyzers provide size distribution in volume, number and surface area in one measurement, with an overall sizing range from 40 nm to 2000 µm. An additional module allows to expose the sample to ultrasonic pulses, i.e. testing for agglomeration.