Self contained PMT housing for quantitative spectroscopy and imaging low light measurements
For spectroscopy and microscopy experiments in the UV/Vis/NIR region of the spectrum, a photomultiplier tube (PMT) is the ideal detector for quantitative low light level measurements. A PMT is extremely sensitive, with very wide dynamic range so it can also measure high levels of light. PMT’s are also very fast so rapid changes in optical signals can be reliably monitored. As a practical matter, PMTs are durable, long-lived, and economical.
HORIBA provides a simple, self contained PMT housing that operates in either analog or photon counting modes with the flick of a switch. This ambient PMT housing is ideal for standard side-on PMTs that are used from 185 to 900 nanometers. It has a very low dark count for a non-cooled PMT housing providing a dark count of only ~ 50 to 500 counts per second (cps) depending on the PMT selected.
Although the quantum efficiency (QE) of a PMT is less than that of a silicon photodiode or avalanche photodiode (APD), a PMT has a much lower limit of low light detection due to the high current amplification (~ 107) of the electron multiplier in the PMT. It is because of this large gain and low noise that a PMT provides significantly better low light sensitivity than a photodiode or APD.
HORIBA's photomultiplier detection system is very convenient and easy to use. It is built as a complete unit using modern design techniques and components. Everything needed to quantitate the intensity of light is packaged into a compact, attractive housing that attaches conveniently to your experiment. There are no unsightly boxes for power supplies or a multitude of cables tangled on your bench-top. The system incorporates a high voltage supply, all detector electronics, and the controls in a compact, attractive housing that also contains the PMT. You have a choice of standard PMTs to choose from or you can select from any other 1 1/8-inch side-on photomultiplier tubes that operate from -200 to -1,100 Volts DC. The PMT high voltage is shown on a digital display on the housing or you can select to show the actual analog signal from the PMT with just a flip of a switch. The high voltage can be adjusting manually or controlled externally with a signal at the “External Voltage Control” BNC. Power is delivered from an external AC adapter that is included.
All controls and displays are available on the front and side of the OBB PMT housing.
LCD display of high voltage or signal
|Dimensions (WxDxH)||4 x 4 x 8 inches|
|Input||± 15 VDC, 250 mA|
|High Voltage||-200 to -1,100 VDC manually adjustable LCD displays actual cathode voltage|
|External High||0 to +5 VDC (0 = -200 V, 5 = -1,100 V)|
|Voltage Adjust||Continuously adjustable|
|Input Regulation||± 0.05% max. (for 15 V ± 1 V input).|
|Load Regulation||± 0.05% max.|
|Ripple||100 mV p-p max.|
|Temperature Coefficient||± 0.01% max. (+5 to 40°C)|
|Drift||± 0.03%/hr. max. (after 15 minute warm-up)|
|Gain Settings:||1 µA = 1 V|
0.1 µA = 1 V
0.01 µA = 1 V
0.001 µA = 1 V
|Time Constant Settings:|
(with Corresponding Analog Frequency)
|0.05 msec (20 KHz)|
0.5 msec (2 KHz)
5 msec (200 Hz)
50 msec (20 Hz)
500 msec (2 Hz)
|Offset Correction:||± 50 nA|
|Signal Output on BNC connector:||Analog voltage|
|Linear Dynamic Range:||5 orders of magnitude*|
|Dead Time:||250 ns|
|Signal Output on BNC connector:||TTL|
* Linear dynamic range of the OBB photon counting PMT housing. The intensities were produced by attenuating the fluorescence emission of a fluorescein sample with neutral density filters.
Clinical chemistry measurements are based on optical spectrometry for most of the blood molecules and also based on potentiometry for a few blood ions.
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