The DET40/75 can also be used as a current amplifier in so-called total yield operation: by measuring the MCP’s output current on the anode with a pico-ammeter the total particle flux on the detector input over a wide range down to the single particle counting regime can be determined
Also, there is a special type of transparent timing anode that allows placing custom read-out circuits behind the detector, either in vacuum or, in combination with a RS-DET40/75, right on air-side of a flange-mounted detector.
Timing electronic schemes:
For all MCP timing detector applications RoentDek supplies the same type of FT4TP feedthrough assembly (with or without mounting device) which takes care of high voltage input (e.g. from HV2/4-type supplies) and signal decoupling for output to electronic recording devices. Depending on the actual application there is a choice of read-out electronics:
For “simple” counting applications at quasi-continuous rates up to 2 MHz and with no or only modest temporal resolution demand, the LET1+ is an economic solution. It provides a digital output signal (NIM or TTL) for counters like the RoentDek RM6 or TDC timing devices.
If high temporal resolution (down to 100 ps FWHM) is required a combination of FAMP1+ and CFD1 is appropriate, followed by a high precision TDC (e.g. the TDC4HM or TDC8HP). Even higher temporal resolution can be obtained by using a fast analog digitizer like the fADC4.
For bunched operation, i.e. whenever a large number of particles during a short period are to be detected, a combination of FAMP1+ and fADC4 is the optimal choice. This read-out scheme expands operation even to particle fluxes when several particles arrive simultaneously and individual signals overlap. This bridges the gap to the “current mode” of MCP when individual particle detection turns into recording of a fluctuating current.
As variation of detectors with “simple” timing anode RoentDek can alternatively provide structured anodes with multiple independent detecting elements. An example is the DET40_5 with five independent anode elements (Pentanode). Signals from each element can be picked up via rear-side contacts. The concept can be expanded to any custom-defined number of elements (“pixels”) with variable shapes.
Front and rear view of a Pentanode mounted to the rear-side MCP carrier ring
Depending on the number of read-out elements RoentDek can provide adequate signal feedthrough and decoupling solutions based on the FT4/12/16TP product range, followed by standard timing electronics circuits or advanced read-out via fast ADCs (RoentDek fADC4) to allow for imaging applications with spatial resolution well below pixel size, employing charge-centroiding algorithms.
The DET40/75P with phosphor screen:
RoentDek offers the DET40/75 timing detectors optionally with phosphor screen. Compared to "industrial-grade" assemblies RoentDek supplies devices for high-end scientific applications. This means that the MCP stack is of same quality and specs as employed for single particle counting and imaging. The screen is of selected quality with choice of material. It does not need an aluminum cover so that decent light output is already achieved at comparably low bias. This makes handling, mounting and operation of the detector user-friendly (e.g., no excessive high voltage needed). The detector can be mounted anywhere inside the vacuum vessel as long as the screen can be viewed by a camera through a window. The assembly is modular, components can easily be replaced. It is possible to combine particle counting/timing with recording an image on the screen.