Photomultipliers
Introduction
Channel Photomultipliers
With the introduction of the Channel Photomultiplier (CPM), PerkinElmer Optoelectronics has succeeded in the development of a brand new, ultra sensitive optical detector dedicated to replace common photomultipliers (PMTs) and avalanched photodiodes in a multitude of applications. The CPM takes advantage of a unique detector principle, combining compact design, high dynamic range, extremely low noise and fast response time.
This high performance device offers substantial advantages for analytical applications like emission-spectroscopy, fluoroscopy, atomic-absorption-spectroscopy as well as bio- and chemo-luminescence. The CPM is also suited for a variety of life science applications, use in industrial and medical equipment and high-end physics.
The CPM components are available in three different diameters (1/3, 1/2, 3/4 inch). All CPM can be supported as the bare component (Cxxx), as a module including high power supply (MH version), as module allowing DC operation (MD version) and in as single photon counting module (MP version).
Channel Photomultiplier Module
In an electronic color separation system having a photomultiplier tube device in the scanning unit thereof, a diffuser plate is disposed between a light source and a photomultiplier tube in the immediate vicinity of said photomultiplier tube. The diffuser plate allows a uniform amount of light to impinge on the photomultiplier tube and prevents production of undersirable output signals.
The photomultiplier provides extremely high sensitivity and ultra-fast response. Photomultiplier tubes (PMT) have high bandwidth and noise-free gain on the order of a million. This makes them ideal for the detection of extremely low light or short pulses of light. Photomultipliers can be used to detect photons from 115nm to 1700nm. A typical Photomultiplier consists of a photoemissive cathode (photocathode) followed by an electron multiplier and an electron collector (anode).
Traditionally, photomultiplier tubes have been used for these applications.1 A photomultiplier tube is a vacuum tube detector that uses a coated photocathode to convert incident photons into photoelectrons, which then are accelerated by the high electric field. Their interaction with multiple metal dynodes causes a shower of electrons, which are collected at the anode of the detector. The electrons are read out as a current that indicates the level of light incident on the photocathode surface. Depending on the configuration of the photomultiplier tubes and the voltages that are applied, the detector can operate in single-photon-counting mode as well as in analog or linear mode. In single-photon-counting mode, the detector must amplify the signal to a level where a single photon — incident on the detector surface — causes a measurable signal at the output of the detector. A photomultiplier tube uses high-voltage power supplies on the order of 1000 to 2000 V and external discriminator circuits to convert the electric charge signal into a digital signal. When in photon-counting mode, the signal is binary, allowing the number of incident photons to be counted and the arrival time of the photon to be determined from the timing of the detector’s output pulse. Single-photon-counting mode allows a wide range of measurement techniques — such as fluorescence lifetime imaging and laser rangefinding — that rely on knowing precisely the arrival time of the photon. Single-photon-counting techniques are ideal for signal fluxes of less than 5 million photons per second. Above that rate, photon arrival time is hard to discriminate because the possibility that two or more can arrive at the same time is increased. Higher signal levels require analog or linear mode of operation to accurately determine the signal level.
The photomultiplier tube (PMT) is among the most popular photosensitive devices. Various tube types and scintillator treatments permit use of these detectors from the Extreme Vacuum Ultraviolet (EUV) through the Visible and into the near Infrared. They provide large photosensitive areas, secondary emission multiplication (high gain), low dark noise and fast time response. Photomultipliers are ideal for a broad range of spectroscopy applications. The Model 650 provides a light tight housing for mounting 52mm end on type photomultipliers. The Model 658 accommodates 28mm end on PMTs. All end-on photomultiplier housing assemblies are provided with a socket for a specified tube, tubes are specified separately. The housing has connectors for current output and high voltage (HV) input. Some models are equipped with scintillators for vacuum ultraviolet (VUV) operation. The scintillator converts invisible vacuum ultraviolet light to a Visible light emission, easily detected by sensitive PMTs.
Contact Information:
Marketing and Marketing Communications
Francine S. Bernitz, Global Marketing Director
Illumination and Detection Solutions
PerkinElmer
35 Congress Street
Salem, MA 01970, USA
Telephone: 978-224-4321
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Anthony Lauletta
Marcom Manager,
Illumination and Detection Solutions
PerkinElmer
35 Congress Street
Salem, MA 01970, USA
Telephone: 978-224-4127
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.