After the test, a graph of the glow-curves is shown that represents the change in counted photons that occured when the temperature increased.It is then possible to analyze and modify the glow-curves by applying various algorithms and comparing the curves with previously saved curves.Using NI products, IPSES developed this thermoluminescence (TL) analysis system for material science and physics departments, specifically for dating ceramic archaeological materials.When radiation is incident on a material, some of the energy may be absorbed and re-emitted as light with a longer wavelength."Using Lab Windows/CVI helped us immediately implement complex analysis algorithms because we could use algorithms already developed in ANSI C by research institutes.Compared to other ANSI C development environments, the library functions and numerous manageable, customizable graphics features offered in Lab Windows/CVI help easily interface the system to the NI PCI-GPIB board." - Gianluca Pizzocolo, CLD, Lab Windows/CVI and NI Test Stand Certified Developer, IPSES The Challenge: Implementing an integrated hardware and software system that can date archaeological or historical materials by analyzing emitted luminescence from heated samples.It is essential to make detailed comparisons of the spectra since the dating procedure is based on a comparison of glow-curves: the natural TL emitted by a sample is compared with the TL emitted by a sample collected from the same object after an exposure to a known radioactive source (β and α) for a due time.We implemented sophisticated, intuitive zoom functions for all the graphs.
The system consists of the following components: The system’s most important features are accurately controlling and stabilizing heating ramps up to 550 °C with a rise rate between 0.5 °C and 15 °C per second.
To meet these requirements, a control system with closed-loop, proportional–integral–derivative (PID) control was implemented.
To meet these requirements, we implemented a closed-loop, proportional–integral–derivative (PID) control system that has a high-precision heating process and intelligently manages the photon counting process using autoranging to concentrate on the actual count and maintain appropriate full-scale resolution.
To ensure the system is fast and responsive and can transfer data to a PC in real time, we selected the NI-488.2 GPIB bus as the communication interface.
The NI PCI-GPIB DMA controller helped us achieve reliable, fast communication, and we avoided any possible interruption during data transfer.