TCSPC and Time Tagging Electronics
Scalable Multichannel Event Timer & TCSPC Unit
- Up to 64 independent input channels with 5 ps base resolution
- Scalable via extension units à 16 channels
- Common sync channel (up to 1.2 GHz sync rate)
- Ultrashort dead time (650 ps), no dead time across channels
- Hardware access to data stream via FPGA link
- Ref In / Ref Out / PPS In / White Rabbit interface for multi-device synchronization
- Drivers and demo code for custom programming
- NEW: Multifunctional on-board event filters
The MultiHarp 160 is designed as a plug-and-play event timer and Time-Correlated Single Photon Counting (TCSPC) unit which is optimized for applications that require a large number of fast and precise timing channels. The high quality and reliability of the MultiHarp 160 is reflected by our unique 5-year limited warranty.
Scalable up to 64 input channels
The number of input channels can be scaled to your needs: the main unit (MultiHarp 160 M) provides 16 of them and can be expanded with up to three extension units (MultiHarp 160 X). Each extension unit adds 16 channels to the event timer, thus providing a choice of 16, 32, 48 or 64 synchronized input channels. The MultiHarp 160 M also features a synchronization channel as a timing reference for all 16 to 64 input channels. This synchronization channel supports sync rates of up to 1.2 GHz for periodic sync rates. The data from all input channels are combined into a single data stream that is accessible via the USB 3.0 interface. No additional synchronization tools are required.
All channels of the MultiHarp 160 – including the common sync input – can be used as detector inputs, e.g., for coincidence correlation or coincidence counting. The MultiHarp 160 is also perfectly suited for performing TCSPC with multiple detectors using forward start-stop operation. Here the common sync channel allows for synchronization with the excitation source.
Fast and precise event timing
The MultiHarp 160's smartly designed time-to-digital converters (5 ps base resolution, <650 ps dead time) allow to fully exploit the count rate limits of time-correlated single photon counting, without having to compromise on the time resolution for many modern single photon detectors. With its ultrashort dead time, multiple photons per excitation cycle can be detected even at the highest repetition rates achievable by modern picosecond pulsed lasers (requires a detector from the PMA Hybrid Series).
Each input channel also features easily accessible parameter settings, which include the trigger parameters as well as programmable timing offsets and hold-off times.
Multifunctional on-board event filters
The MultiHarp 160 has user-defineable on-board event filters to efficiently reduce the file sizes and the amount of data sent via the data interfaces (USB, external FPGA interface).
Data interface for external FPGA boards
For applications with high count rates at multiple input channels, the data read-out speed and/or the data processing speed by the computer is the major bottleneck. This bottleneck can be bypassed by reducing the data size that is sent to the computer. Such a data reduction is for example done in the histogramming mode of the MultiHarp 160, where TCSPC histograms sent to the computer are calculated out of the arrival times of the input signals by the hardware itself.
To enable the greatest possible flexibility, the time tagging data stream of the MultiHarp 160 can be accessed by an external FPGA board via a dedicated FPGA interface. This way, the method of data preprocessing can be tailored to the specific application.
White Rabbit ready event timer
White Rabbit is a fully deterministic, Ethernet-based timing network which provides sub-nanosecond accuracy and precise synchronization of devices over large distances. Thanks to its White Rabbit interface, the MultiHarp 160 is ready to be integrated into set-ups that are using this emerging technology.
Download our free White Paper to learn more about the flawless interoperability of the MultiHarp devices with the switches from Seven Solutions.
|Input Channels and Sync||Constant level trigger on all inputs, software adjustable|
|Number of detector channels
(in addition to Sync input)
|16 (Main unit)
32 (Main unit + first extension unit)
48 (Main unit + first and second extension unit)
64 (Main unit + first, second, and third extension unit)
|Input voltage operating range (pulse peak into 50 Ohms)||-1200 mV to 1200 mV|
|Input voltage max. range (damage level)||±2500 mV|
|Trigger edge||falling or rising edge, software adjustable|
|Input pulse width||> 0.4 ns (rise/fall time max. 20 ns)|
|Time to Digital Converters|
|Minimum time bin width||5 ps|
|Timing precision*||< 45 ps rms|
|Timing precision / √2*||< 32 ps rms|
|Dead time||< 650 ps (can be increased via software up to 160 ns in steps of 1 ns)|
|Adjustable programmable time offset for each input channel||±100 ns, resolution 5 ps|
|Differential non-linearity||< 10 % peak, < 1 % rms (over full measurement range)|
|Maximum sync rate (periodic pulse train)||1.2 GHz|
|Count depth||32 bit (4 294 967 295 counts)|
|Full scale time range||328 ns to 2.74 s (depending on chosen resolution: 5, 10, 20, …, 41 943 040 ps)|
|Maximum number of time bins||65 536|
|Peak count rate per input channel||1.5 × 109 counts/sec for 2048 events|
|Total sustained count rate, sum over all input channels||MultiHarp 160 M:
332 × 106 counts/sec (166 × 106 counts/sec per row of 8 input channels)
MultiHarp 160 X1, X2, X3:
332 × 106 counts/sec (166 × 106 counts/sec per row of 8 input channels)
|T2 mode resolution||5 ps|
|T3 mode resolution||5, 10, 20, …, 41 943 040 ps|
|FiFo buffer depth (records)||268 435 456 events|
|Peak count rate per input channel||1.5 × 109 counts/sec for 2048 events|
|Total sustained count rate, sum over all input channels**||80 × 106 counts/sec via USB 3.0 interface|
|FPGA Data Interface|
|Throughput T2/T3 Mode||200 × 106 counts/sec|
|Throughput T2 Direct Mode||200 × 106 counts/sec per row of 8 input channels
+ 78 × 106 counts/sec for SYNC input
|Latency T2 Mode||4.5 µs to 5.0 µs|
|Latency T3 Mode||4.5 µs to 5.5 µs|
|Latency T2 Direct Mode||SYNC: 1.7 µs to 1.8 µs
Others: 0.8 µs to 1.2 µs
|Period||programmable, 0.1 µs to 1.678 s (0.596 Hz to 10 MHz)|
|Pulse width||10 ns typ.|
|Baseline level||0 V typ.|
|Active level (pulse peak)||-0.7 V typ. (50 Ohm)|
|External Marker Inputs|
|Input type||LVTTL, < 50 ns rise/fall time, > 50 ns at HIGH or LOW (max 5V for 1 µs), software adjustable hold-off|
|Ref IN||10 MHz
200 … 1500 mV p.p.
50 Ohm; AC coupled
|Ref OUT||Default: 10 MHz
White Rabbit mode: 31.25 MHz
1400 mV p.p.
50 Ohm; AC coupled
|PPS IN||1 s, LVTTL|
|White Rabbit interface||connector for SFP module|
|PC interface||USB 3.0|
|PC requirements||Dual Core CPU or better, min. 2 GHz CPU clock, min. 4 GB memory|
|Operating system||Windows 10/11|
|Power consumption||Max. 150 W|
|Operation environment||Indoor use only|
|Operation altitude||Max. 2000 m above sea level|
|MultiHarp 160 M (main unit)||incl. feet and handles 285 × 425 × 100 mm|
|MultiHarp 160 X (extension unit)||incl. feet and handles 285 × 425 × 62 mm|
* In order to determine the timing precision it is necessary to repeatedly measure a time difference and to calculate the standard deviation (rms error) of these measurements. This is done by splitting an electrical signal from a pulse generator and feeding the two signals each to a separate input channel. The differences of the measured pulse arrival times are calculated along with the corresponding standard deviation. This latter value is the rms jitter which we use to specify the timing precision. However, calculating such a time difference requires two time measurements. Therefore, following from error propagation laws, the single channel rms error is obtained by dividing the previously calculated standard deviation by √(2). We also specify this single channel rms error here for comparison with other products.
** Sustained throughput depends on configuration and performance of host PC.
All Information given here is reliable to our best knowledge. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications and external appearances are subject to change without notice.
Easy-to-use software included, custom programming supported
The MultiHarp 160 comes with a Windows software package that provides all important functions such as setting measurement parameters, displaying results, loading / saving of measurement parameters and measurement curves. Important measurement data, including count rate, count maximum, position and peak width are continuously displayed. A comprehensive online help system eases the user into fully employing the capabilities of the MultiHarp 160. A library for custom programming, e.g., with C, C#, LabVIEW, Matlab, and Python is also included.
Operation and software features
The MultiHarp 160 can be used in various operation modes:
Measurement of the accumulated events as a function of time, manually started, stopped manually or upon overflow or expiration of a chosen collection time or upon reaching of a defined number of counts. 512 curves with up to 65 536 time channels, more than 4 billion counts per time channel (32 bits).
Repetitive measurement and on-line display, very useful for optical alignment. Flicker free histogram display updates and large rate meters for work in the distance.
Time-Tagged Time-Resolved mode(s) (TTTR)
Continuously recording events without onboard histogramming straight to disk. Together with the channel number the arrival time of each event with respect to the beginning of the experiment is recorded for ultimate flexibility in offline data analysis, e.g. in single molecule detection and Burst Integrated Fluorescence Lifetime (BIFL) measurement as well as time-resolved FCS, coincidence correlation (antibunching, etc.) or time-interval analysis. Fast transfer and a large FIFO buffer allow huge count rates without any loss of data. Up to four different external synchronization signals ("markers") can be fed into the data stream and allow to synchronize the data acquisition with external hardware such as scanners for Fluorescence Lifetime Imaging (FLIM).
The MultiHarp 160 software allows the control of all measurement parameters provided by the MultiHarp 160 module. The input channels are programmable for a variety of signal types. All functions of the system are controlled by a software interface for Windows 10 and 11. The software provides functions such as the setting of measurement parameters, display of measurement results, loading and saving of measurement parameters and measurement curves. Important measurement characteristics such as count rate, count maximum and position, and histogram width (FWHM) are displayed continuously. A comprehensive online help function shortens the user's learning curve. Software upgrades for extended functionality will be available with further product development. A library (DLL) for custom program development is also provided and allows building your own applications, e.g., in LabVIEW , C++, Delphi or Matlab. Demo code is provided for an easy start. A Windows as well as a Linux version is available. The libraries are API compatible, so that applications can easily be ported between the platforms.
Current software and developer's library version: 184.108.40.206
The new software version supports event filtering in the time tagging modes (requires suitable firmware) and Windows 11.
Time-Tagged Time-Resolved (TTTR) mode allows the recording of individual count events directly to hard disk or computer memory. The timing of each photon is captured as an event record without any early data reduction (such as on-board forming of histograms). This mode is particularly interesting where e.g. the dynamics in a fluorescence process are to be investigated in depth. The availability of the full timing information permits photon burst identification, which is of great value e.g. for single molecule spectroscopy in a liquid flow. Other typical applications are Fluorescence Correlation Spectroscopy (FCS) and Burst Integrated Fluorescence Lifetime (BIFL) measurements. Together with an appropriate scan controller, TTTR mode is also suitable for ultra fast Fluorescence Lifetime Imaging (FLIM) with unlimited image size. Applications beyond fluorescence spectroscopy are e.g. time interval analysis, quantum optics and related basic rearch. The MultiHarp 160 actually supports two different time-tagging modes, T2 and T3 Mode - a concept originally introduced with previous products of the Harp series. They differ slightly in their use of the input channels. By using the suitable mode, a very wide range of applications can be covered.
In T2 Mode all signal inputs of the MultiHarp 160 are functionally identical. There is no dedication of one channel to a sync signal. All inputs can be used to connect photon detectors. The events from all channels are recorded independently and treated equally. In each case an event record is generated that contains information about the channel it came from and the arrival time of the event with respect to the overall measurement start. If the time tag overflows, a special overflow marker record is inserted in the data stream, so that upon processing of the data stream a theoretically infinite time span can be recovered at full resolution. Dead times exist only within each channel but not across the channels. Therefore, cross correlations can be calculated down to zero lag time. This allows powerful new applications such as FCS with lag times from picoseconds to hours to be implemented with one instrument. Autocorrelations can also be calculated at the full resolution but of course only starting from lag times larger than the deadtime.
The T3 Mode is specifically designed to use periodic sync signals from pulsed lasers with high repetition rate up to 1.2 GHz. This signal is connected to the dedicated sync channel. As far as the experimental setup is concerned, this is similar to classic TCSPC in histogramming mode. In addition to the picosecond start-stop timing, the channel number is recorded and each event is time tagged with respect to the beginning of the experiment. The time tag is obtained by simply counting sync pulses. From the event records in T3 mode it is therefore possible to precisely determine which sync period a photon event belongs to. Since the sync period is also known precisely, this furthermore allows to reconstruct the arrival time of the photon with respect to the overall experiment time. If the counter overflows, a special overflow marker record is inserted in the data stream, so that upon processing of the data stream a theoretically infinite time span can be recovered.
External Event Markers
The MultiHarp 160 supports capturing up to four external marker events in the TTTR modes that can be fed to the instrument as TTL signals via a suited SubD connector. These events are recorded as part of the TTTR data stream. This allows to precisely synchronize the TTTR measurement with almost any experiment, e.g. with the movement of piezoscanners for imaging applications or with the switching of electro-optic modulators.
The acquisition software provided with the instrument comes with a rich set of demo programs that enable users to write their own analysis and display programs for TTTR data. Users who prefer to use standard data analysis algorithms out of the box may want to consider the powerful QuCoa software suite for coincidence correlation and advanced coincidence analyses, or SymPhoTime64 for a wide range of time-resolved Fluorescence analyses.
The MultiHarp 160 can be used for various applications that call for a time tagger featuring a large number of synchronized inputs without compromises in time resolution and data throughput, such as:
- Coincidence Correlation
- Quantum Communication
- Linear Optical Quantum Computation
- Quantum Entanglement
- Diffuse Optical Tomography
- Time-Resolved Fluorescence
- Time response characterization of optoelectronic devices
- Time-Resolved Photoluminescence (TRPL)
- Fluorescence Lifetime Imaging (FLIM)
- Phosphorescence Lifetime Imaging (PLIM)
- Multi-color Lifetime Imaging
- Fluorescence Correlation Spectroscopy (FCS)
- Fluorescence Lifetime Correlation Spectroscopy (FLCS)
- Single Molecule Spectroscopy/Detection
- TRPL Imaging
The following documents are available for download:
- Datasheet MultiHarp 160
- Detailed information on external FPGA interface (zip file)
- Brochure about PicoQuant's photon counting and timing products
- White Paper: TCSPC Multi-Device Synchronization using MultiHarp and White Rabbit
- Technical note: Time-Correlated Single Photon Counting (TCSPC)