On eBay Now...

Fast, biplanar vacuum photodiode for short laser pulses type ITL FD125, vintage For Sale

Fast, biplanar vacuum photodiode for short laser pulses type ITL FD125, vintage


Buy Now

Fast, biplanar vacuum photodiode for short laser pulses type ITL FD125, vintage :
$224.00

The device is a very fast vacuum photodiode to detect short laser pulses, type FD125, made by ITL Technology, UK. Vintage, on market in 70's, it consists of a vacuum tube (diode) made of a photocathode and a mesh anode, parallel and at short distance to each other, to minimize the time of flight of the emitted photoelectrons from the cathode to the anode. The photodiode is a current generator,i.e., it generates a current proportional to the light power received by the device. The design minimizes the risetime of the current generated by the photodiode, which is terminated into a coaxial 125 Ω connector. With a matched 125 Ω load, a peak voltage of 10 V - 20 V can be generated, which is proportional to the incoming laser power. With an appropriate 125 Ω characteristic impedance coaxial cable, it is connected to a real time, fast oscilloscope with a risetime of less than 0.35 ns (or a bandwidth more than 1 GHz), with an input impedance of 50 Ω - 125 Ω. The 70's oscilloscope model was Tektronix 519 oscilloscope. Besides the photodiode tube itself and the output connector, the device has a matching impedance mount and a high-voltage (HV) BNC connector. The latter connects to the high-voltage DC power supply to apply the voltage to the photodiode electrodes. The main characteristics of the device follows. Window diameter: 20 mm. Type of photocathode: S1, with spectral sensitivity 300 nm - 1200 nm (see last figure of its spectral sensitivity - initially intended and used to detect Nd:glass laser mode-locked pulses, at 1060 nm, can work well also in near UV and visible). Maximum supply voltage at HV BNC connector: 2 kV. Risetime of the generated pulse for a step voltage: 0.2 ns. Some additional info on its properties can be obtained from the paper of Smith et al."Impulse Rise and Fall Times of Biplanar Vacuum Photodiodes", Appl. Opt. vol. 12, pp. 1606-1610 (1973). The device was used occasionally in early (70') experiments for mode-locking Nd:glass lasers. Vintage device, the original cost was in the range of $2,000. Although today there are faster and smaller photodetectors, the device is still functional and useful for laser hobbyists, for educational purposes, or as a collectible item of laser history.



Buy Now

ITT FW-114 Ultra-Fast <500 picoseconds Biplanar Phototube 300-700 nm gamma picture

ITT FW-114 Ultra-Fast <500 picoseconds Biplanar Phototube 300-700 nm gamma

$250.00



Hamamatsu R1193U-03 Biplanar Phototube Electron Tube Ultra-Fast picture

Hamamatsu R1193U-03 Biplanar Phototube Electron Tube Ultra-Fast

$279.99



Hamamatsu R1193U-01 Biplanar Vacuum Phototube Ultra-Fast Photodetector w/Case picture

Hamamatsu R1193U-01 Biplanar Vacuum Phototube Ultra-Fast Photodetector w/Case

$139.99



Popular Tutorials

Alarms and Indicator Circuit diagrams Audio electronic circuits list Circuits for Cars/Motorcycles Computer/PC Hardware Circuits : Design Ideas : Fun/Games Circuits : Signal/Sequence/Misc. Generators : Home/Garden related Circuits : Lights & LED Circuits : Motor Circuits : Music related Circuits : < Oscillator Circuits : Power Supply (PS) Circuit diagrams : Radio,transmitter,receiver circuits : Remote Control Circuit diagrams : Robotics related Circuits : Sensors : Telephone Circuit diagrams : Test & Measurement Circuits :