Avalanche Photodiodes | FMB Oxford

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Avalanche Photodiodes

Avalanche Photo Diodes

The FMB Oxford APD detector is an ultra-fast detector system, using an avalanche photo diode, for X-ray scattering experiments up to 20keV.

It offers the ultimate in speed, resolution, efficiency and noise levels whilst maintaining a robust and easy to use architecture, making it ideal for experiments with a large dynamic range, time resolved measurements and fast photon counting.

The system requires an APD detector head, signal processing electronics and a signal cable.

APD Detector Head

5mm x 5mm 5mm x 5mm
60mm x 30mm x 16mm body - in-air60mm x 30mm x 16mm body - DN16KF vacuum compatible head
Be windowBe window


Maximum count rate100MHz *
Diode area5mm x 5mm
Housing dimensions60mm x 30mm x 16mm
Photon efficiency50% that of NaI up to 10keV *
Noisebelow 1Hz *
Diode gain200x at 370V bias
Preamplifier gain60dB per stage at 100MHz
Rise time 10%-90%<2ns *
FWHM<4ns *

*indicative performance figures obtained at
the National Synchrotron Light Source,
Brookhaven National Laboratory

APD Electronics

The APD Electronics package, built to a design developed at the European Synchrotron Radiation Facility offers the user maximum flexibility; it supplies the bias voltage to the detector head, and has an integrated counter/timer which can be operated in local (front panel) or remote (computer controlled) modes.


  • front panel operation through a user-friendly LCD graphic display with touch panel
  • easy user interface for remote operation mode
  • up to 500V diode bias
  • very low noise
  • rugged, reliable package
  • wide dynamic range and linearity – seven decades
  • LabView software is provided and can be utilised with the RS232 communication port for remote configuration and data retrieval
NIM Module two units wide
Selectable modes local (front panel), remote
Remote connection serial or parallel
Maximum count rate up to 100MHz
HV APD biax up to 500V
Remote mode software included
Energy resolution 20% to 25% at 25keV

APD Cables

APD Cables are available in various lengths..

Ordering Info

ItemPart Number
APD Detector Heads
5x5mm 110µm sensor, in-air APD0010
5x5mm 110µm sensor, with KF DN16 flange, in vacuumAPD0011
APD Electronics
APD pulse processing unit ACE, NIM 1 channel APD0002
APD to ACE Cables
APD to ACE PPU cable, 5mCBY01501
APD to ACE PPU cable, 10mCBY01502
APD to ACE PPU cable, 15mCBY01503
APD to ACE PPU cable, 20mCBY01504
APD to ACE PPU cable, 30mCBY01505
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