Integrating Current Transformer & Beam Charge Monitor

ICT integrates bunch charge without loss

High sensitivity for pC resolution pulse measurement



BCM-IHR full scale ranges

400pC to 800nC

Noise in single bunch

0.55 pCrms


ICT combines two nested transformers: a shorted one-turn current transformer loads the full bunch charge instantly into capacitors. Then the charge is transferred to the output by a readout transformer, at a slow pace, to avoid core losses. Cores are specially annealed to lower their coercive field and further minimize core loss. The ICT signal is integrated by BCM-IHR, a boxcar type synchronous differential detector. The output voltage proportional to the beam pulse charge is available 30μs after the trigger. It is maintained up to 400μs, then reset.  Another pulse can then be measured.


In-flange ICT are mounted directly in the beam line.
Available for many pipe diameters from 1” to 250mm.
Also with elliptical aperture or other arbitrary shape aperture. Ceramic gap, shields and wall current bypass are included.
Bellows are not required.
Bakeable up to 185°C

UHV compatible


In-air ICT installation, over the vacuum chamber requires installation of a “gap” to prevent the wall current from flowing through the ICT aperture.

The gap can be a brazed ceramic ring or an organic material O-ring depending on the vacuum requirements.

Typical installations include bellows, a wall current bypass and an electromagnetic shield enclosing the ICT completely.


BCM-IHR-E processes the signal from an ICT.
Specially developed hybrid circuits amplify the charge and integrate it with low noise and high linearity.
Output is a bipolar voltage directly proportional to the beam charge.
A built-in Calibration Generator provides on-line assurance of measurement reliability.
BCM-IHR-E inserts into a wired station of BCM-RFC, the 19” 3U RF-shielded chassis including power supplies.
Up to 10 stations per chassis can be installed.
















In-air models:

100°C (212°F) any time

In-flange models:

100°C (212°F) any time
150°C (300°F) on option
185°C (365°F) on option

 Core saturation

2 mT radial field
2A permanent DC current 

 Radiation damage

Standard SMA  PTFE: 1E3 Gray max
Rad-tolerant SMA   PEEK: 6E7 Gray max
1E17 n/cm2 max


ICT Sensitivity

From 0.5Vs/C to 20Vs/C

Full scale ranges (BCM)


Most sensitive

Least sensitive

800pC, using 5Vs/C ICT

400nC, using 0.5Vs/C ICT

 Noise single bunch



±8V, available 50µs after trigger
held for 350µs (up to 10ms on option)

Calibration pulses

1pC, 10pC, 100pC, 1nC, accuracy ±2%