Photonis designed the Daly Detector to reduce noise due to ion feedback while negating many of the surface characteristic changes seen in other electron multipliers at high pressure.

High gain (>1E6)
Operates at ambient pressures up to 30 mTorr
Reduces ion feedback
Enhanced detector lifetime
Minimal retrofit modifications

Technical information

Physical Characteristics   Electrical Characteristics
Annular Input Dimensions 22 mm OD
16 mm ID
    Dynode Voltage 1500 – 5000 V
Input Grid 60% Transmission
(16 mm ID is occluded)
  PMT Voltage -600 V
(-1000 V Max)
Operating Pressure (Maximum) 30 mTorr   PMT Current <360 µA
Operating Temperature Range -50° to +40°C   Signal Response Time <100 ns
      Detector Gain >5E5
      Detector Dark Current < 5 nA



The Daly Detector consists of a conversion dynode, a scintillator, and a photomultiplier tube. Incoming ions are accelerated to the conversion dynode producing secondary electrons. By combining the high sensitivity of a photomultiplier tube with a cylindrically-focused electron optics configuration to out-perform similar products, Photonis’ Daly Detector provides the highest sensitivity available on the market today. This innovative technology has been optimized for use with an annular input at vacuum levels up to 30 mTorr. Because of its geometry, the Daly Detector is capable of measuring positive and negative primary ions using secondary electrons in both cases.

How does a daly detector work?

Daly DetectorPhotonis’ Daly Detector provides superior detection for a variety of instruments. Each detector consists of a conversion dynode, a scintillator, and a photomultiplier tube. The combination of these three technologies produces a larger sample which ultimately leads to higher sensitivity.
In the picture, you can see how the components of our Daly Detector work together.




Daly Detectors



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