Photek Vacuum Imaging Detector (VID)
From our partners at Photek:
The Vacuum Imaging Detector (VID) is an open face detector without a photocathode. It is designed to be mounted into or onto a vacuum chamber. The VID is designed to detect charged particles, UV photons and neutrons. It is available with either a phosphor screen, solid anode or resistive sea which provides re-configurable anode options. The phosphor screen can also include a time of flight module which provides timing response to 5 ns. Typical applications include electron microscopy, nuclear physics research and VUV imaging.
Seen in the image to the right is a Photek VID240 customized by Sydor's team to include a power supply, gate module, readout camera, custom mounting, and a custom lens. Sydor's technical teams work alongside our customers to determine ways to optimize our partner's products for the end-user's application.
Features:
Easy to use and fully-integrated systems available
High speed performance
Ultra-high resolution
Allows for the detection of molecules, fragments, anti-matter,
neutrons, leptons, hadrons, photons, & more
Applications:
Mass Spectroscopy
Electron Microscopy
VUV Imaging & more
RESPONSIVITY OF VACUUM COMPATIBLE DETECTORS
The basic detector element is a microchannel plate(MCP).This is fabricated from a microtubular matrix of secondary electron emissive glass,and responds well to electrons,other charged particles.The approximate responsivity,collated from various published sources ,is shown in figure 1.The exact response depends upon many parameters including the angle of incidece of the charged particles and the history of the MCP. MCP vacuum baking sometimes reduces the responsivity but also reduces the noise generated by these detectors.
CsI coating will enhance the responsivity of an MCP, but as this is chemically reactive to moisture, it may be unsuitable for application where the detector has to be repeatably exposed to air .
Powder scintillators are normally used to convert the electron output of microchannel plates to an optical output in Vacuum Imaging Detectors. Table 1 shows the time response and optical output of common powder scintillators.
VACUUM IMAGE DETECTORS
Ptotek holds stocks of 12,18,25,40 and 75mm active diameter MCPs and fibre optic screen assemblies. The general schematic format is shown in Figure4.
A typical assembly , VID240 is shown in Figure3. This particular device is designed for UV spectroscopy,and used a 40/50 fibre taper outside the vacuum for connection to a linear diode array
potek manufactures a wide range of image intensifiers the metal-ceramic bodies of these devices are often used as the basis for the photek range of vacuum compatible detectors . Figure 3 shows a bare image intensifier adapted to be mounted on a vacuum manipulator M3 screw connector with flying high voltage leads and operated as a beam finder.
Image Intensfier bodies can also be mounted directly onto a vacuum flange as shown in Figure5 .The device illustrated is part of an ultra high resolution photon counting UV imager with resolution
The inherent resolution of a scintillator screen on its own is typically 75 lp/mm. With one MCP .This is reduced to 30-40 lp/mm,but a gain of approximately 104 is achieved ;with 2MCPs,resolution is in the range of 20-30 lp/mm but the gain in the range of 105 to 107 is possible.
The gain and temporal response of the detector depends on the phosphor screen selected of which characteristics are shown in Table1