Accelerator System Overview

A complete NEC electrostatic accelerator system overview:

Injection beamline(s) – Includes ion source(s) and other optical and diagnostic components leading up to the accelerator beamline
Pelletron – Includes the pressure vessel, accelerator beamline, charging system, and more
High energy beamline(s) – Includes optical and diagnostic components from the exit of the Pelletron up to and including the endstation(s) or detector(s)
Control system – Includes hardware and software for computer control of the full accelerator system, specifically customized for each system configuration.

Customization of each system’s component configuration to meet user’s specific needs.

Source and Injection Beamline

Injectors begin with one or more ion sources that produce positive or negative ion beams. Bending magnets or electrostatic analyzers, typically following the source, focus the ion beam into the accelerator. Also, diagnostic equipment and other focusing elements are also an integral part of the injector. Various configurations can be used depending on the user’s requirements. Detailed information regarding our various available sources found in the sources section.

Single source injector with NEC Alphatross source

Dual source injector with NEC SNICS (left) and Alphatross (right) sources, without safety cages

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Pelletron

Electrostatic accelerators work on the basic principle:

Negative ion beams: attracted to a positive terminal
Positive ion beams: accelerated away from a positive terminal.

Decades ago, charging belts, or Van de Graaf generators, functioned to create a high voltage terminal in air. As the scientific community realized the importance of creating higher voltage terminals, experts conducted experiments to increase the terminal voltage by using different charging materials and insulating gases. Continuous research through the decades resulted in the creation of the most stable and reliable electrostatic accelerator system in use today: the Pelletron.

Pelletrons consist of the following:

Pelletrons can either be tandem or single ended. Tandem Pelletrons start with negative ions that go through a stripping process to break up molecules and strip electrons, thus creating the necessary positive beam. Single ended Pelletrons, on the other hand, start with a positive ion produced directly from the source inside the terminal.

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High Energy Beamline

After the positive beam accelerates, it exits the pressure vessel and enters the focusing beamline, which as the name implies, continues to focus the beam. At this point, a single extended beamline leading to an analysis chamber, implanter, or other detector exists. Or, there is a switching magnet with up to 7 ports for multiple extended beamlines. Additional beam focusing, steering, or diagnostic components are all typically part of the extended beamlines. For more information regarding these components, refer to the Products section. Like the injector beamlines, the high energy beamlines can be configured to meet user specific needs.

A post acceleration switching magnet with extended beamlines at the +/- 15 degree ports.

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Control System

The accelerator system runs via a centralized control system. All accelerator parameters needed for normal operation are interfaced with the control console.

Most of the controls and readouts interface with the control console via an in-house data acquisition system known as the NEC ACT system (prior to 2009, interfacing was via CAMAC).

The control console consists of a dedicated computer system, assignable meters and knobs, and an oscilloscope for displaying signals.

The NEC accelerator control software, AccelNET, configures the computer system. AccelNET manages the display and control functions through a database management system operating in a multitasking environment, Linux. NEC configures AccelNET for each system by tailoring its database to the accelerator configuration.

Parameters are displayed in two (2) formats: text formatted pages of parameter lists and graphic displays of the system layout. Controls can be adjusted by menu-driven restoration of stored values, increment/decrement buttons, keyboard input of the desired parameter value, or assigning the parameter to a knob for analog mode adjustments. Then, values of readouts display on the monitor and assign to either a meter for analog display or the on-screen strip chart recorder.

We incorporate vacuums and other interlocks into the control system to protect personnel, equipment and samples.

Operators may save and restore preferred system configurations and setup preferences. This allows for an easy beam startup with little to no fine tuning needed.

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