Ion Beam Analysis (IBA) Endstation

The NEC ion beam analysis (IBA) endstation (model RC43) is a versatile accessory for Pelletrons or other ion beam accelerators.

When combined with a Pelletron accelerator and associated ion source and beamline components, the IBA endstation provides a complete IBA system, offering automatic data collection. The system can perform qualitative analysis using multiple techniques simultaneously such as RBS, ERD, NRA and PIXE.

Applications

The RC43 endstation is capable of many IBA techniques, each of which have a long list of applications. Detectors can be included for the following techniques:

Rutherford Backscattering (RBS)
Elastic Recoil Detection (ERD) *
Nuclear Reaction Analysis (NRA) *
Particle Induced X-ray Emission (PIXE) *
Particle Induced Gamma-ray Emission (PIGE) *
Ion beam Induced luminescence (IBIL) *

* optional

NEC also offers a microprobe for beam sizes of 20 microns and external beam capabilities.

An interior view of the RC43 chamber: (1) sample; (2) fixed silicon surface barrier (SSB) at 170°; (3) movable SSB and filters at 180° to 30°; (4) X-ray detector; (5) gamma detector at 0°; (6) X-ray detector filters; (7) zoom camera; (8) microprobe lens; (9) light; (10) chamber

IBA Endstation Design

Chamber

The scattering chamber is constructed primarily from aluminum. It has a view port, target alignment laser, and video camera. The base of the chamber provides stable support for the target manipulator, solid state particle detector, beam collimator, and turbo-molecular pump. A target load lock is placed in the lid to permit quick (less than 5 minute) changes of target holders while maintaining high vacuum.

The chamber can accommodate up to 16 samples, 1 cm x 1 cm, side by side. It is electrically isolated and can be used as a Faraday cup for precise beam current measurements.

Target Manipulator

The NEC IBA endstation incorporates a 5-axis sample manipulator with a motorized rotary drive. This manipulator allows precise control of target movement in the X, Y, and Z directions with polar and azimuthal rotation. The rotary drive includes five stepper motors. The samples are positioned by the control computer, which controls all five motors simultaneously. Local control of the manipulator is also available when adding samples.

Current Integrator

A digital current integrator is provided to measure total ion beam currents and provide gate signals for the RBS or NRA measurements by monitoring total ion current on the target.

Pumps and Valves

A turbo-molecular pump and forepump are furnished to pump the target chamber and beamline near the chamber and the target load lock. Solenoid and pneumatic valves with appropriate controllers and gauges are provided to automatically pump out or vent the chamber.

Control and Data Analysis

Sample positioning and data acquisition with the IBA endstation is accomplished with a remote control system. This control system includes software for both qualitative and quantitative analysis.

Qualitative Analysis

The IBA endstation’s Analytical Data Collection software performs qualitative analysis.

Features:

Gathers up to 6 spectra simultaneously including RBS, ERD, NRA, and PIXE.
Analyzes sample in real time with verified and qualitatively complete results.
Capable of printing plots of channeling and microprobe data.

Quantitative Analysis

The RUMP program developed by L.R. Doolittle of Cornell University, as well as other analysis programs, performs quantitative analysis.

Features:

Allows for automatic calibration of the theoretical model and automatic chi-squared fitting of the model to the experimental data.
Presents data in either depth profile format, or various yield vs. energy formats.
Displays an element’s surface scattering energy and height.
Calculates peak thickness and plots a peak in atomic fraction vs. depth format.
Plots up to 10 spectra and can be overlaid with color and line styles that are automatically changed.
Separates overlapping data with selective plots of individual elements.

The IBA endstation control system also communicates with the accelerator control system itself, receiving beam energy information and sending instructions to produce the optimal beam conditions during real time runs.

Accessories

NEC also offers a high resolution RBS detector system. This detector adds the capability of Ångstrom range depth profiling.

Options

The standard IBA Endstation includes a Silicon Surface Barrier detector and a detector preamplifier with digital pulse processor for RBS analysis.

Additional detectors available include:

ERD Particle Detector

An additional silicon surface barrier detector for ERD or glancing RBS measurements.
An insulated feedthrough with a support arm to allow movement of the detector from 30° to 170°.
An ERD foil holder that is mounted on the support arm with positions for up to 6 different foil thicknesses.
Electronics, including the detector preamp, bias supply, and digital pulse processor.

Gamma Ray Detector

2” x 2” NaI(T1) Scintillation Detector, preamplifier, amplifier, and high voltage bias power supply for NRA analysis.
A reentrant tube that allows the detector to be closely placed directly behind the target.
A higher resolution HPGe detector is also available.

PIXE Detector

25 mm² Silicon Drift Detector (SDD) for PIXE analysis.
A preamp, spectroscopy amplifier, power supply, X-ray filter holder, MCA with KLM lines, and necessary cables.
A modern, up-to-date computer with GUPIX analysis software, color monitor, keyboard, mouse, and stand.
Files of data acquired on the IBA endstation computer are easy to transfer directly to the PIXE analysis computer via Ethernet.