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TNT Description

Dernière mise à jour : jeudi 18 octobre 2007, par Cayetano SANTOS

TNT is a digital multi-channel gamma spectrometer system based on digital processing technology specially conceived for low-level gamma spectroscopy mainly with HPGE detectors showing major advantages over traditional analog technologies. A new range of Flash ADC components with high sampling rates of 100 Mhz and resolution of 14 bits are available. With these devices it is now possible to develop a very high count range, multi-channel system for gamma-spectroscopy.

Operation

Each channel of the TNT module accepts signals directly from a detector preamplifier. After a digitally controlled gain and offset stage, signals are digitized. Triggering, pile-up inspection and filtering of the data stream is performed in real time in a field programmable gate array (FPGA).

Using this approach it is possible to capture the detailed shape of the preamplifier signal, and then perform digitally all essential data processing functions, including precise energy measurement over a range of 6 keV - 10 MeV ; rise time analysis, ballistic deficit correction and pulse shape analysis. Thus we can obtain both the energy and the pulse shape information from one detector using one channel of the module.

Data readout and slow control are performed throught an universal serial bus (USB). A data transfer of up to 40 MB/s has been observed, which stands for low dead times at counting rates.

The TNT is operated through TUC’s graphical user interface. It allows to update all parameters relevant to the data acquisition, store them in settings files, and run the modules. Update of the firmware is possible throught the USB2 port.

Synchronization of several modules is also possible using dedicated LVDS signals.