Particle Tracker
Advacam’s MiniPIX TPX3 Telescope camera is an arrangement of the two timepix3 detectors stacked in layers equipped with either Si or CdTe sensors of various thicknesses (up to 2 mm CdTe). Each timepix3 pixel measures the energy deposited by particle and time of arrival (1.5 ns precision). The combination of Silicon and thick CdTe layer can be advantageous for the construction of Compton camera optimized for low energies of gamma rays. Modules are internally synchronized: They use the clock frequency and shutter signal derived from one common master. Both modules are connected to the DAQ computer(s) each via own USB2.0 Micro-B connector. The USB hub can be used to aggregate these two lines. The power consumption of the whole device is 2.6 W.
Mijnipix TPX3 Telescope has applications in space for monitoring of cosmic rays (so called space weather). The development is performed in tight collaboration with several partners including ESA (European Space Agency) and NASA.
There are several additional application fields:
The measured directional distribution can be visualized using such spherical mapping. The logarithmic intensity (flux) is shown as color.
Device parameters
Symbol | Parameter | Min | Typ | Max | Units | Comment |
TA | Temperature Range | 0 | 50 | 70 | °C | |
Φ | Humidity | 0 | 55 | 60 | % | Not condensing |
Symbol | Parameter | Min | Typ. | Max | Units | Comment |
VCC | Supply Voltage | 4.0 | 5.0 | 5.5 | V | Comply with USB 2.0 |
ICC | Supply Current | 300 | 500 | mA | Comply with USB 2.0, Mode dependent | |
P1 | Power Dissipation | 2.5 | W | |||
Bias Voltage Source for Sensor Diode | ||||||
VBIAS | Bias Voltage (positive version) | 3 | 450 | V | Max. limited internally according to sensor type | |
VBIAS | Bias Voltage (negative version) | -4 | -450 | V | With CdTe or CZT sensor |
Symbol | Parameter | Min | Typ. | Max | Units | Comment |
ff | Frame-rate | 16 | fps | with USB 2.0 Host | ||
TFREAD | Frame Readout Time3 | 62 | ms | |||
fp | Pixel type hit-rate in ToT+ToA mode (pixels per second) | 2.35 x 106 | pps | with USB 2.0 Host |
Symbol | Parameter | Si | CdTe | Units | Comment | ||||
Thickness | 100 | 300 | 500 | 1000 | 1000 | 2000 | µm | ||
Minimum energy threshold | 2.0 – 2.7 | 2.0 – 2.7 | 2.0 – 3.0 | 2.0 – 3.0 | 2.5 – 4.5 | 3.0 – 5.0 | keV | ||
σ Thl@60 | Energy resolution in ToT mode (σ @ 60 keV) | 1.2 – 2.6 | 1.3 – 2.7 | 1.4 – 3.5 | 1.7 – 3.6 | 2.8 – 5.4 | 2.9 – 8.3 | keV | |
σThl@122 | Energy resolution in ToT mode (σ @ 122 keV) | 3.4 – 6.0 | 4.5 – 9.9 | keV | |||||
Typical detectable energy range for X-rays | 2.0 – 60 | 2.5 – 500 | keV | See chart below | |||||
Pixel size | 55 | µm |
Number of Events | number of events (hits) in the pixel during exposure time (this mode is suitable mainly for frame type readout) |
Time-over-Threshold (ToT) | measured as number of periods of 40 MHz clock signal (25 ns step) when amplifier output signal stays over the energy threshold. The ToT can be transformed to energy in keV using per-pixel-calibration function. The coefficients for per-pixel-calibration are unique for each detector pixel and they are stored in configuration file delivered with device. The energy calibration is valid only for given values of other detector parameters as delivered in configuration file (especially threshold) |
Time-of-Arrival (ToA) | number of periods of 40 MHz clock signal (25 ns step) from start of exposure till the event is registered by pixel (i.e. pulse in pixel crosses the threshold). The range is 409.6 µs. Additional 16 bits are added in FPGA in readout electronics so that the total range is 26.8 seconds. The additional bits are usable only if the pixel hit rate is below maximal value (see fp in table of Performance characteristics) |
Fast-Time-of-Arrival (FToA) | time difference between event detection and next clock signal measured with step of 1.5625 ns. Range is 4 bits. The combination of ToA and FToA gives precise time of event detection in nanoseconds using following formula: Time [ns] = ToA*25 – FToA*1.5625 ToA and FTOA are combined together by software. If saved then ToA and FToA are stored as separate items |
Frame type measurement | No data is sent out of device during the exposure time. All measured events are accumulated in counters of pixels. Event counter is incremented and ToT is integrated for all events. The measured data is read-out after end of exposure time for all pixels with nonzero content. No measurement can be performed during readout process. |
Pixel type measurement | Information about all hit pixels is read-out immediately and continuously during exposure time. If hit rate is below maximal value (see fp in table of Performance characteristics) then there is virtually no deadtime. |
Type | Mode | Range | Description |
Frame (reading all pixels after end of exposure) | Event+iToT | 10 bit + 14 bit | 2 output frames per exposure: 1st Events = Number of events in pixel, 2nd iToT = total time over threshold for all events in pixel. |
iToT | 14 bit | 1 output frame: iToT = total time over threshold for all events in pixel. | |
ToA | 18 bit | 1 output frame: ToA+FToA1 = Time of Arrival of first event in pixel. | |
Pixel (reading only hit pixels continuously during exposure) | ToT+ToA | 10 bit + 18 bit | 4 numbers per pixel per event: Position, ToT, ToA and FToA. |
ToA | 18 bit | 3 numbers per pixel per event: Position, ToA and FToA1 defined.. | |
Only ToT | 10 bit | 2 number per pixel per event: Position and ToT. |
The device is supplied with USB flash disk containing installer of PiXet-Pro software, unique device configuration and calibration file and protocol on quality tests. The device casing is made of aluminum with sliding cover made of stainless steel protecting sensor window. The communication and powering is provided by USB Micro-B connector and cable. |
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1 ToA and FToA are combined together by software automatically. If saved, ToA and FToA are stored as separate items (for Pixel type measurement).
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