Beam DCCT (NPCT) - Bergoz Instrumentation - #1

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Four ranges ±20mA, ±200mA, ±2A and ±20A <0.5uA/!Hz noise, i.e. resolution, on option DC to 10 kHz (-3dB) frequency response < 0.1% linearity error NPCT package includes spares for all electronics Application The Parametric Current transformer is used on most particles accelerators in the world to measure the average beam current. It is an essential instrument for accelerator tuning and operation. It is primarily used on particle sources, cyclotrons, medical synchrotrons, HEP research accelerators and light sources. It is often the only intrinsically calibrated beam instrument in an accelerator and serves as a reference to calibrate other beam diagnostics. Operating principle The NPCT works on the second harmonic detection principle. Two cores are modulated to deep saturation in opposite phase. A primary DC current flowing through the cores shifts the cores’ working point in opposite polarity which generates a second harmonic of the modulator frequency. The primary current AC component is detected by an AC Hereward transformer. The two circuits are cascaded in a common feedback loop to generate a magnetic flux which always cancel the primary current flux. The NPCT output is the voltage developed by the feedback current passing through a precision resistor. New-PCT Chassis with NPCT-E electronics and power supplies The New Parametric Current Transformer is the latest evolution of the Unser Transformer, commonly called DCCT, developed at CERN in 1966 by Klaus B. Unser. V2.0 In-flange.NPCT to mount in the beam line In-flange.NPCT with 96-mm aperture NPCT sensor for “in-air” installation A typical installation is over the vacuum chamber; it requires a “gap” to prevent the wall current from flowing through the sensor aperture, bellows, a wall current bypass, which can serve as RF shield. It often requires an external magnetic shield. “In-air” NPCT sensor with 175-mm aperture New-PCT New Parametric Current Transformer DC beam current non-destructive measurement