Volumescope 2 SEM Features

A workhorse solution for volume EM

Optimized for stability and image quality, the Thermo Scientific Volumescope 2 SEM is easy to use and is capable of reliably generating high-quality volumetric data from a wide array of samples. It can run automatically for hours or even weeks to capture 3D data from large biological specimens.

 

The debris trap and swipe features keep the imaging face clear of cut fragments, ensuring that each image contributes optimally to the volumetric dataset. This combines with multi-energy deconvolution to provide optimized isotropic datasets with z-resolutions down to 10 nm.

 

The microtome unit is quickly and easily exchanged in and out of the SEM, which is ideal for a multi-use instrument where flexibility is key.

Volumescope 2 SEM key features

Any debris remaining on the surface of a specimen after cutting can impact SEM imaging and significantly reduce the overall quality of a 3D dataset. The debris trap and swipe features of the Volumescope 2 SEM work in combination to alleviate this issue.

 

The debris trap sits above the knife and attracts cut fragments, removing them from the specimen. The swipe feature then automatically detects any residual debris on the sample surface and removes it as well. Together, these features help to ensure the collection of clean, high-quality data.

Volumescope 2 SEM debris trap

Multi-energy deconvolution SEM (MED-SEM) is a novel way to improve axial resolution through combined mechanical and optical sectioning. Following in situ sectioning of the block-face using a diamond knife, the freshly exposed tissue is imaged several times using increasing accelerating voltages. These images are subsequently put through a deconvolution algorithm to derive several optical subsurface layers, forming a 3D subset. By repeating this cycle, the Volumescope 2 SEM can generate isotropic datasets with 10 nm z-resolution.

The Volumescope 2 SEM is a multi-use instrument with a microtome unit that can be quickly and easily mounted and removed from the SEM. This means that the system can be used for many different applications, including array tomography or EDS, with minimal hassle. 

 

Samples can remain mounted in the microtome so that long experiments can be paused and continued at a later date without the need for lengthy realignments.

The Volumescope 2 SEM can operate in both high- and low-vacuum modes. Acquisition parameters can be selected based on the sample type in order to minimize charging and optimize image quality. 

Thermo Scientific Maps Software showing the different vacuum options of the Volumescope 2 SEM.

Designed with ease of use in mind, the Volumescope 2 SEM allows jobs and system settings to be reused, and multiple regions of interest can be selected during data acquisition. Visualization and navigation can also be performed simultaneously to help ensure the optimal region is being captured at any time. This ease of use combines with designed-in stability to enable multi-week acquisitions as standard for large volume experiments. 

Multi-location acquisition of volumetric data with the Volumescope 2 SEM
Multiple imaging locations can be configured in Maps Software with different acquisition conditions at each region.

Volumescope 2 SEM specifications

Electron optics
  • High-resolution field emission SEM column
    •  High-stability Schottky field emission gun
    •  Compound final lens combines an electrostatic, field-free magnetic lens and an immersion magnetic objective lens
  • Dual objective lens combining electromagnetic and electrostatic lenses

Source lifetime

24 months

Automation
  • Auto bakeout
  • Auto start
  • No mechanical alignments necessary
  • Automated, heated apertures
  • User guidance and column presets

Stage

Double stage scanning deflection

Electron beam
  • Continuous beam current control and optimized aperture
  • Beam current range: 1 pA to 400 nA
    • For serial block-face imaging: 50 pA – 3.2 nA
  • Landing energy range: 20 eV – 30 keV
  • Accelerating voltage range: 200 V – 30 kV
    • For serial block-face imaging: 500 V – 6 kV
  • Resolution at optimum working distance and routine SEM high-vacuum imaging
    • 0.8 nm at 30 keV STEM
    • 0.7 nm at 15 keV
    • 1.0 nm at 1 keV

Chamber
  • Inside width: 340 mm
  • Analytical working distance: 10 mm
  • Ports: 12

Detectors
  • Serial block-face imaging detectors
    • T1 segmented lower in-lens detector
    • VS-DBS: LoVac lens-mounted BSED
  • T2 in-lens detector
  • Everhart-Thornley SE detector (ETD)
  • IR-CCD
  • Low-vacuum SE detector
  • STEM 3+ retractable segmented detector
  • Additional detectors available

Vacuum system
  • Complete oil-free vacuum system
  • 1 × 220 l/s TMP
  • 1 × PVP-scroll
  • 2 × IGP
  • Chamber vacuum (high-vacuum): <6.3 × 10-6 mbar (after 72 hours pumping)
  • Low-vacuum mode up to 50 Pa for charge compensation of non-conductive samples
  • Evacuation time: ≤3.5 minutes

Sample holders
  • Standard multi-purpose holder uniquely mounts directly onto the stage and hosts up to 18 standard stubs (Ø12 mm), three pre-tilted stubs, two vertical and two pre-tilted row-bar holders
  • Each optional row-bar accommodates six STEM grids
  • Wafer and custom holders

For Research Use Only. Not for use in diagnostic procedures.