You are here

Home » Facilities » Accelerator Lab

Beamline Experiment End Stations

Currently there are four end-stations:

  1. A general purpose ion beam analysis end-station; for Rutherford Backscattering Spectrometry (RBS), Particle Induced X-ray Emission (PIXE) , Elastic Recoil Detection Analysis (ERDA) using a stopper foil and Nuclear Reaction Analysis (NRA).
  2. A high energy ion irradiation endstation: for large area (5 x 5 cm ) irradiation in vacuum and a small area (mm2) irradiation in atmosphere.
  3. A fixed microbeam for internal and external beam and ultra low fluence broad-beam irradiation: (Under construction)
  4. Internal beam MeV ion Microscope: This facilitates RBS, PIXE and ERDA analysis with resolution down to 1µm.

General Purpose Ion Beam Analysis End Station

Status:  Operational
Type: Stainless steel chamber  60 cm dia.
Vacuum:  ~10-6 mbar, turbo-pumped.
Beam spot size: Defined by aperture 1 mm2.
Sample mounting: Clips
Detectors: Si:Li X-ray detector for PIXE., Si surface barrier  detectors for NRA, stopper foil ERDA  and RBS. NaI-well detector suitable for low-resolution NRA.
Data collection: PC based multi-channel analyser.

This end-station is configured as a general-purpose system suitable for student exercises. Additional detectors for e.g ion-induced fluorescence  and secondary electrons can be easily added.

High-Energy Ion Irradiation End Station

Status:  Operational
Type: Stainless steel irradiation chamber  60 cm dia.  with transparent Plexiglas or stainless steel top-plate.
Irradiation environment: high vacuum or atmosphere
Vacuum:  ~10-7 mbar, cryo-pumped.
Beam scanning: magnetic in X and Y
Beam spot size: Defined by aperture 1-10 mm2 or by scanned beam up to 5 x 5 cm. External beam up to 3 mm dia.
Sample mounting: Clips
Detectors:  N/A
Data collection: Charge digitizer.

This end-station is a flexible end-station for many types of ion irradiation requiring fluences in the range 1012-1018 ions cm-2.  All the ion species produced by the Pelletron Accelerator can be used for irradiation. A proton beam can be bought out into atmosphere. This can be using a 1 mm x 1mm 200 nm thick Si3N4 radiation window, or a Ti radiation window. When an external beam is used a Plexiglas box is used as a barrier to prevent body parts being exposed to the primary beam.

Internal/External MeV Ion Microprobe with Fixed Beam

Status:  Under commissioning (July 2017)
Type: Oxford triplet quadrupole lens system without scanning. 
Irradiation environment: high vacuum or atmosphere
Vacuum:  ~10-7 mbar, turbo-pumped.
Beam scanning: None
Beam spot size: ≲10 µm in X and Y
Sample mounting: Sample stage for transmission or thick target.
Detectors:  RBS detector for fluence measurement. Si X-ray detector for external PIXE.
Data collection: OMDAQ 2007/ DAQ3

This is a specially developed microprobe that can be configured for use:

  • as an external beam for e.g. external microbeam PIXE measurements, on-line gas chromatography of plasma desorbed organic molecules.
  • as an internal focused beam for plasma desorption mass spectroscopy, proton beam writing with an external beam using mechanical scanning. And
  • in the same manner as Abbe’s critical illumination microscope condenser lens to deliver ultra-low fluxes of 1-3 MeV ions (106-109 ions cm-2 s-1) to  simulate charged particles in space.

A special feature is that the external beam can be delivered into a removable glove-box which facilitates experiments with biological materials that require up to BSL-2 conditions.

Internal Beam MeV Ion Microprobe

Status:  Operational
Type: Oxford triplet quadrupole lens system scanning. 
Irradiation environment: high vacuum
Vacuum:  ~10-7 mbar, turbo-pumped.
Beam scanning: X-Y
Beam spot size: ≲1 µm in X and Y
Sample mounting: Manual or computer controlled sample stage for transmission or thick target measurements.
Detectors:  RBS detector for fluence measurement. Si SDD X-ray detector for PIXE, RBS, , On and Off-axis Scanning Transmission Ion Microscopy (STIM).
Data collection: OMDAQ 2007/ DAQ3,   OM IONSCAN software for proton beam writing.  GeoPIXE for off-line analysis.

This workhorse end-station is a standard Oxford triplet configuration from Oxford Microbeams with a large target chamber to facilitate use of large solid-angle X-ray detectors. The system is equipped with a fast beam blanker and can be used for proton beam writing. The main task of the system is for minor and trace element mapping in metal and biological samples.

Supporting Equipment

In order to assist users in preparing and characterising samples prior to analysis in the mcrobeams the centre has a collection of microscopes.

JEOL (model 6460LV) Scanning Electron Microscope: This has a resolution of 10 nm and an electron energy from 300 eV to 30 kV. It is equipped with secondary electron imaging and an EDX imaging system with a Si detector. The samples are mounted on a 5-axis motorised stage. An IR camera can be implemented. Carbon arc and sputter coaters are available for coating samples to render the surface conducting.
Optical microscopes: A range of othr microscopes is available including a stereo dissection microscope, Zeiss biological microscope and a metallurgical microscope.
Sample preparation: A well-equipped materials chemistry laboratory is on-site with faculties for mechanical polishing, chemical cleaning and etching, spin coating and thermal bonding.
Mechanical workshop: The on-site mechanical workshop is equipped with two lathes, a vertical mill, two pillar drills, mechanical saws and abrasive wheels.