3 MV Tandetron

3 MV Tandetron

The 3 MV Tandetron accelerator was installed in 2012 and is mainly dedicated to applied physics experiments. The machine is fully equipped to do ion beam analysis (IBA) and implantation experiments. The first beam-line has all the necessary detectors to perform particle induced X-ray emission (PIXE), particle induced gamma ray emission (PIGE), Rutherford backscattering (RBS) and elastic recoil detection analysis (ERDA).

We also have the possibility to do micro-beam analysis using a high performance focusing electrostatic quadrupole lens.

The second beam-line is dedicated to implantation experiments, having the possibility to scan a wide sample surface (18x18 cm) with very accurate control of the dose. The third beam-line is a multipurpose beam-line used mainly for nuclear astrophysics experiments.

3 MV Tandetron
3.0 MV Tandetron accelerator system comprising the following major components

In order to keep the high voltage on the terminal the tank of the accelerator an insulating mixture of gases is used (10 bars of SF6 and Nitrogen mixture). The high voltage terminal is kept in its central position by the accelerating column. The column is a succession of stainless steel and insulating glass. The steel pieces are linked with resistors (300 MOhm) and this represents a voltage divider from the maximum terminal potential to the ground potential (the ends of the tank).

1. Dual source injector system

Negative sputter ion source Model 860A

  • Extraction gap
  • Manual in-line gate valve
  • Electrostatic Einzellens
  • Y-steerer
  • Duoplasmatron ion source Model 358

  • Extraction gap
  • Sodium charge exchange canal
  • 90 deg. analyzing magnet
  • 2. "T" Shape – medium current plus – Tandetron accelerator:

  • Q-snout
  • Pressure vessel
  • Accelerator tubes
  • Voltage grading resistors
  • Medium current plus terminal gas stripper with stripper canal, stripper gas re-circulating pump and motor-generator set
  • Carbon foil stripping system
  • 3. Medium-current Cockroft-Walton type HV power supply including:

  • HV multiplier and rectifier stack
  • All solid state driver
  • HV control and stabilizer system
  • Generating Voltmeter (GVM)
  • Capacitive Pick up Unit (CPU)
  • 4. X-ray radiation shielding
    5. Electrostatic quadrupole triplet lens
    6. Switching magnet:

  • Water-cooled vacuum chamber
  • Power supply
  • Polarity reversal switch
  • 7. Beamline and end-station for Ion Beam Analysis / Ion Microprobe that includes (beamline #1):

  • Beam defining object slits (X&Y)
    • X-steerer
    • Y-steerer
  • Beam defining collimator slits (X&Y)
  • Electrostatic quadrupole lens for µ-beam applications
    • Retractable Faraday cup after the beam defining collimator slits
    • Beam profile monitor (BPM)
  • Experimental analysis chamber approx. 390 mm in diameter and 500 mm in height and sample loading port
  • Multi-sample holder 4-axis sample manipulator with:
    • sample holder for multiple samples
    • three stepping motor controlled rotations
    • one stepping motor controlled Y-translation
  • Fixed detector holder with ion implanted charged particle detector
  • Electronics and power supplies including:
    • Pre-amplifier
    • Amplifier
    • Detector bias power supply
    • Data acquisition system
    • NIM Bin and power supply
    • CCD camera
  • LN2 trap
  • RBS analysis software
  • Manual movable RBS detector holder with ion implanted charged particle detector with all necessary electronics and acquisition system
  • ERD measurements: • Multiple foil holder for ERDA measurements
    • Stepping motor driven foil carrousel
  • Retractable HPGe X-ray detector for PIXE having
    • Be entrance window
    • LN2 cooling dewar and all necessary electronics for acquisition and analysis systems
  • Retractable HPGe Gamma-ray detector with LN2 cooling dewar
  • Beam extraction system with Si3N4 window and high precision XYZ sample moving system
  • 8. Beamline and end-station for Ion Implantation that includes (beamline #2)

  • Electrostatic X-Y beam sweep system
  • Resolving slotted aperture
  • Beam monitoring system with:
    • Auto tracking system
    • Beam monitoring control
  • Enlarged implantation chamber including:
    • Faraday cup assembly with secondary electron suppressor
    • Un-cooled carousel for one wafer size of choice • Heatable target holder for one wafer size of choice • Coolable target holder for one wafer size of choice • Beam shutter
  • 9. Beamline and end-station for Cross Section Measurements (beamline #3)

  • Experimental vacuum chamber of about 500 mm in height and 400 mm in diameter;
  • Target holder
  • Detector holder with the possibility to move around the target
  • Multiple ports
  • Some of the typical ion beams delivered by the 3MV Tandetron Accelerator
    Accelerated beam Energy, up to MeV (approximate values) Current, up to eµA
    1H 6 15
    2H 9 5
    6Li 12 0.25
    7Li 15 0.1
    10B 18 10
    11B 18 40
    12C 21 100
    13C 21 1
    14N 23 0.5
    16O 21 3
    18O* 21 0.006
    19F 25 0.05
    26Mg 25 0.2
    27Al 25 1
    28Si 25 70
    31P 25 70
    58Ni 25 20
    63Cu 25 20
    75As 25 10
    197Au 25 80

    Note: Apart from noble gas species, practically every stable isotope can be accelerated.

    *The user should provide the isotope.