Photomultiplier tube (PMT) is a vacuum tube device in which light flux ranging from infrared to ultraviolet spectrum is converted into a flux of electrons with further amplification.
For the detection of very weak light signals the photon counting method is used to acquire maximum information. Discrete dynode PMTs, MCP-PMTs, avalanche diodes, hybrid PMTs are typically used as photon counting detectors. Among these types of detectors MCP-PMTs from VTC Baspik have the advantage of fast response, low dark count rate, increased surface area, low power consumption, and stable operation under the exposure to magnetic fields.
Typical applications
- In nuclear physics as a component of scintillation counter In laser and television devices
- In optical instrumentation
- For the detection of low-level radiation
- In nondestructive inspection aids as a detector in scanners for X-ray film digitization
PMT with a built-in voltage divider
Voltage divider is mounted on the PMT vacuum unit providing the necessary electrode potentials of the device.
MCP-PMT which are photon counting devices with a built-in voltage divider are available in two versions:
- Sapphire-2AM for UV light
- Topaz-M for visible spectrum
PMTs can be supplied as vacuum units or with a voltage divider built into the same housing as the vacuum unit.
PMT basic parameters
| Parameter | Topaz-M (For visible spectrum) | Sapphire-2AM (For UV spectrum) |
|---|---|---|
| Photocathode type | Bialkali (КNaSb) | Cesium telluride |
| Input window type | С50-2 glass | Magnesium fluoride |
| Spectral sensitivity range, nm | 300– 650 | 120– 360 |
| Integral sensitivity, μA/lm, min | 35 | |
| Photocathode spectral sensitivity at the maximum of spectral response, mA/W, min | 20 | |
| Photocathode active area diameter, mm, min | 17 | 15 |
| Multiplying system type | Assembly of 2 MCPs without IBF | Assembly of 2 MCPs without IBF |
| MCP channel diameter, µm | 8 | 8 |
| Gain (at supply voltage of 3300 V max) | 1×106 | 1×106 |
| Dark count rate density (at 25°C), s-1×cm-2, max | 40 25 typical | 15 5 typical |
| Single electron pulse height resolution, % | 110 max | 110 max |
| Supply voltage, V | 2400 – 3300 | 2400 – 3300 |
See also Particle Detection Techniques Using MCP-PMT.