Bergoz CR-BCM

Current Measurement with sub-nanoamperes resolution of CW beams and macropulses.

Based on a prototype developed by S. Srinivasan and P.A. Duperrex at PSI, the CR-BCM is a re-entrant cavity resonator used as a beam current monitor. The CR-BCM operates at the fundamental mode of resonance, i.e. transverse magnetic mode tuned to a given harmonic of the beam repetition rate.

The fundamental mode of resonance is proportional to the beam current or to the bunch charge of single beam pulses. The re-entrant cavity resonator provides a position- and beam-size-independent response. Calibration check is possible without dismounting the cavity from the beam line.


CRCDS stands for Cavity Resonator Current Detection System.

To form a turn-key solution for low current measurement, the CR-BCM can be associated with:

CRCDS is able to measure currents down to 1 nA with a 100 pA resolution in 500Hz.


  • Beam repetition frequency from 30 MHz to 175 MHz
  • Response time  < 1 µs
  • 100 mm axial length
  • 300 mm external diameter
  • DIMENSIONS: The CR-BCM has fixed outer dimensions for any bunch repetition frequency between 30 MHz and 175 MHz:
    • Axial length: 100 mm
    • External diameter: 300 mm


  • Cavity systems are known for providing a linear response over a large dynamic range and superior sensitivity compared to commonly used current monitors.
  • The CR-BCM is optimized for applications in charged particle radiation therapy facilities, FLASH experiments, radio-isotope production facilities.

Part No. Description Qty Price

Cavity Resonator Beam current monitor, 2nd harmonic


Cavity Resonator Beam current monitor, 2nd harmonic


Cavity Resonator Beam current monitor, 3Rd harmonic


Cavity Resonator Beam current monitor, 3Rd harmonic

Quantity Discount Schedule:
Quantity 2 – 4 5 – 9 10 – 24
Discount 3% 7% 10%

Terms and Conditions

Terms and Conditions:

Prices above are for domestic deliveries to USA, Canada, and Mexico only.
For deliveries in all other countries please contact Bergoz.
Prices are expressed in U.S. Dollars, FCA San Carlos, California.
Prices are subject to change without notice.
Higher quantity and OEM discounts are available.


Visa, MasterCard, Amex, Prepayment before shipment, or Net 30 days (subject to credit acceptance).


Stock to 90 days, depending on quantity.