Low Current Beam Profile Monitor

BPM-90LC

100na beam_100ua gain setting

1na beam_1ua gain setting

10pa beam_10na gain setting

10fa beam_10na gain setting_average mode

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NEC now offers a beam profile monitor that can detect beam current down to the Femto Amp range.

Applications

The Low Current BPM, Model BPM90-LC, is based on the NEC Model BPM90. As with all NEC BPM models, the BPM90-LC can be used with both positive and negative ions, electrons, and neutral beams. The BPM90-LC is ideal for applications requiring measurement of beams with current densities less than 1 µA/cm2.

Low Current Beam Profile Monitor Design

The BPM90-LC utilizes a uniquely modified design of the standard NEC BPM collection method. The design of the standard NEC BPM relies on the collection of secondary electrons from a grounded scanning wire. In contrast, the BPM90-LC utilizes a biased wire and collection area at high voltage. There are 7 gain stages to select from ranging from 0.5 kV to 7 kV. This bias allows the electrons to be focused by a shield into a SSB detector. The detector, coupled with a preamp and amplifier, magnifies the electron signal from the wire. A direct display on an oscilloscope of the magnified signal is present.

Specifications

• Overall Length: 6.7” (17.15cm) – 7.38” (18.73cm) dependent on flange type.
• Standard Housing Flanges: 6.0” or 8.0” OD CF; 6.0” OD NEC; 4.0” O.D. Dependex. Other flange size and type available upon request
• Beam aperture: 1.0” (2.54cm) dia. molybdenum
• Scanning wire: 0.020” (0.5mm) dia molybdenum other wire diameters may be available upon request.
• Maximum beam power: 12 µA
• Minimum detectable beam current: ≤ 1 pA demonstrated

Accessories for Low Current Beam Profile Monitor

For a complete system, an SSB detector, signal preamp, and amplifier are required.

Contact NEC for additional details.

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