RoentDek's major development is a position and time sensitive Microchannel-plate (MCP) detector system with delay-line read-out anodes for advanced particle and photon counting. Please find details below.
If you are interested in a special detector
solution which is not listed but might be provided by us, please inquire.
We are also able to suggest and provide
advanced spectroscopy systems including time-of-flight/imaging
spectrometers (e.g. COLTRIMS) for specific tasks.
We can also provide solutions for the task of
visible light detection in
single photon counting mode.
GUIDE TO THE OPTIMAL RoentDek DETECTOR SYSTEM
The RoentDek MCP detectors with delay-line anode apply an electronic particle (or photon) counting technique.
The electronic circuits register digitally the information on the position and on the arrival time for each individual
particle. The information is available in real-time and free of any "read-out noise" or blur, as known from
and can be correlated with other recordings (or other detected particles) in real time. A detector system consists of
with signal decoupling,
(amplifier and timing discriminator) and
(TDC). In order to achieve a performance best-suited for your application, a few choices
have to be made. This guide shall help you in these decisions. Before going into details you may refer to this document to verify if the detectors are compatible with your application and needs.
1 Detector heads:
A detector head of type DLD or HEX consists of the micro-channel plate (MCP) stack and the delay-line anode. The DET MCP detectors contain a metal plate behind the MCP stack (only timing pick-up).
The MCP stack usually features two (resistance-matched) micro-channel plates with pore sizes of typically 12.5 or 25 microns and a channel length-to-diameter ratio (L/D) between 80:1 and 40:1, stacked in so-called Chevron
configuration. The MCP stack is operated in gain saturation so that every particle hit creates a distinct electromagnetic signal signature and a well-defined charge cloud, which is collected on anode. Due to the characteristics of the delay-line anode several electronic signals on distinct pick-up terminals are produced in a time sequence, which encodes the information on the position and absolute time of the particle impact. The time sequence is usually registered by a (TDC) after front-end electronics' signal shaping.
The standard product choices DLD40, DLD80 and DLD120 use chevron MCP stacks, the number denominating the (approximate) effective MCP diameter. Generally, larger detector heads will give better performance (even for the absolute position resolution). The DLD40 and DLD80 can be delivered with different MCP types (12.5 or 25 microns pore size) and can alternatively be equipped with triple (Z) MCP stacks for improving the
ion-feedback characteristics. This can be relevant in advanced multi-hit applications. The required open area will usually determine the choice of the detector size, but the number of desired position pixels in the image (which depends also on the TDC choice) must be considered, too.
Detectors for multi-hit analysis
(e.g. fragment imaging):
The HEX option (HEX80
is designated for experimental situations where particle bursts
("multi-hit") shall be detected, i.e. it is likely that more than one particle arrives within a short (<100 ns) period.
Detectors with central hole:
RoentDek can deliver detectors with a central hole, allowing a particle/photon beam to pass though the detector (option
detectors are usually built with
Hexanodes (HEX40/o, HEX80/o,
HEX120/o) and have typically a 6.4
mm hole. They often require a special (user-defined) shielding tube.
with improved performance characteristics or
coatings (e.g. for efficiency-enhanced VUV/X-ray
detection) can be
incorporated in our detectors. It is also possible to build
delay-line anodes (e.g. with an internal
phosphor screen) and also delay-line
anodes for one-dimensional read-out
Completely assembled and tested Resistive Screen MCP detectors with anode (e.g. DLD40X featuring an external LC-delay-line anode) for direct flange mounting can be shipped ready-to-use. These have the same imaging/timing properties as the (helical-wire) delay-line of the standard detectors and increased tolerance towards ambient magnetic fields.
Based on this technique TSCSPC-detectors for visible to near-UV single photon counting or scintillator screen imaging (RS-PMT25 and RS-PMT40) are available, incorporating detector heads produced by our collaboration partners Proxivision GmbH or Photek Ltd. Furthermore, TSCSPC-detectors can also be provided based on the helical-wire delay-line anode as encapsulated detector heads for visible and near-UV single photon detection (DLD40PMT and DLD80PMT) with a choice of photo-cathodes.
It is recommended to order a
FT12-TP-type vacuum feedthrough
and signal-decoupling plug with the detector (for HEX-option:
FT16-TP) because the signal
decoupling and biasing of the detector is very critical for the performance.
Furthermore, a mounting gear for the detector head on and with a "Conflat"
vacuum flange can be ordered, options _/100,
_/200, the numbers denominating
the inner flange diameter in mm. Of course, the flange diameter must be
bigger than the outer detector size as given in the product descriptions.
Typically, the mounting gear included in these product options is for the
largest fitting detector size, but it is also possible to order a
feedthrough/mounting-gear on a larger mounting flange (e.g.
FT12-TP/150s for a DLD40 on
a Conflat flange with 150 mm inner diameter). If you need any special
flanges or extra ports in the customarily offered flanges please contact
It should be
noted that the standard "–TP"
option will transform the intrinsically
differential delay-line signals into single-ended signals with 50Ω
impedance. It is possible to order the decoupling plug without this
already contain a
FT12-TP-type decoupling circuit.
However, they might need an extra cooling housing, please contact RoentDek.
3 High voltage power supply
detector requires 5 separate potentials
(plus a sixth if a front mesh shall be independently biased) for operation.
In most cases it is sufficient to supply the "MCP back" and "holder" contact
with the same potential; and the BA3 floating battery box reduces the number
of independent power supply channels needed to 3 or 4. Depending on the task
it might be possible to operate the detector even with only 1 or 2
independent power supply channels (please contact
In any case, the power supplies should
have enough range, stability and excess-current trip protection. Two
versions can be delivered, the HV2/4
with two independent channels (require a NIM bin
SPS2 for operation) or the
applications with MCP front and MCP back on the same polarity, the
High Voltage terminator is
necessary as a voltage stabilizing unit.
customarily a set of amplifying/timing electronic circuit boards (DLATR)
inside a 19" case with mains power supply, the
DLATR board is a constant fraction
discriminator (CFD) circuit with pre-amplifier. The
ATR19 case hosts all
inputs/outputs and controls for operating the boards.
ATR19 is equipped with 6 channels (3
DLATR boards) for
DLD-type detectors or 8 channels
boards) for HEX-type
detectors; in both versions,
one channel is "spare" and available for the
processing of an external signal, or a signal from a second detector (e.g. a
DET40 timing detector with
If the signals shall not be digitized
with a TDC but with fast ADC system (fADC,
see below), we recommend amplifying the
signals from the FT12(16)TP-type
decoupler by a FAMP8
and or FAMP1
(possibly followed by a
MIXA8). Also if a different CFD
than the internal circuit on the DLATR
board shall be used (e.g.
amplifiers shall be used for pre-amplification.
The combination FAMP8
and the new CFD8
represents the optimal readout electronics of
delay-line detectors for advanced
The TDC choice is very important for the
application. So far, the TDC is limiting some performance characteristics of
the detector system like particle throughput and position resolution (and
thus the number of pixels in an image, also depending on the active detector
Currently there is the choice of two
a) the HM1-B
can be operated in several modes. It is
mainly used for fast imaging or imaging&timing applications (not multi-hit)
detectors and allows in the
limit 1 MHz
analog output can produce an on-line
image on an oscilloscope screen (oscilloscope not included). The
HM1-B has also an option to
acquire up to 3 (multi-) hits at a particle rate of up to 15 kHz.
b) the TDC8HP
is a module dedicated for
high resolution imaging and for
multi-hit acquisition. It can
achieve a particle throughput over 100 kHz (CPU-dependent), but does not
have an analog output option.
For detailed advice on the best-suited TDC
choice for your application please contact
Advanced digital read-out:
For advanced applications (e.g. extreme
multi-hit conditions) the use of CFDs and TDCs can become inadequate due to
dead-time limitations and lack of desired
information on the pulse height and shape of the detector signals. For such
demands it is possible to record the signal sequence from the detector by a
fast ADC system (fADC).
supports this technique with adequate
front-end electronics (see above) and data analysis software (please contact
If a complete detector system is purchased,
it can be considered complete concerning all "special" items. Connection
between electronic modules are included if both modules to be connected by
the cables have been purchased.
SHV connection cables between the
high voltage power supply HV2/4
and the feedthroughs are NOT included, but can
be ordered separately.
Standard tools as screw drivers or wrenches,
which are necessary to assemble and mount the detector heads (the detector
heads and mounting gear come as an assembly kit) and for adjusting the
electronic settings are NOT included. Also NOT included is a PC for the TDC
operation . However, the data acquisition software
CoboldPC (for but without Windows
OS) is part of the TDC delivery.
A fast oscilloscope (300 MHz) for single
pulses is necessary for initial signal verification and performance control
For using auxiliary monitoring, operating
several detectors in coincidence or correlating detector signals to external
signals, additional pulse-shaping and multiplexing electronic circuits can
be of necessary. The
COIN4, MIXA8, NIM2ECL
can be useful complementary electronic units in
7 Coincidence setups and COLTRIMS/spectrometer
able to provide advanced setup for operation of two (or more) detectors and
support the correlation between the detector signals and other recordings
from the experiments.
setups or custom
time-of flight spectrometers can be
assembled from standard components.
Since such setups are strongly
application-depended it is necessary to contact
RoentDek for details.