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≡FTDI FT245BL. data bus. A/D converter. USB cable. handshake signals. ≡FTDI FT245BL. USB cable. data bus. Fig. 4: Block diagram. Fig. 5: Internal structure. Fig. 6: UMP2 module. Cover. Source. Vacuum. α -beam. Detector. Washer. Fig. 8: First experimental set-up. - PowerPoint PPT Presentation
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I E A P
Petr Mašek1,2 *, Vladimír Linhart1, Tomáš Slavíček1, Fadahad Mamedov1
1 Institute of Experimental and Applied Physics, Czech Technical University in PragueHorská 3a/22, CZ-128 00 Prague 2 – Albertov, Czech Republic
2 Faculty on Electrical Engineering, Czech Technical University in PragueTechnická 2, CZ-166 27 Prague 6, Czech Republic
* E-mail: Petr.Masek@utef.cvut.cz
R/O Device based on USB1.0 for Spectroscopy DAQ
•Alpha source(241Am) used;
•A semi-continuous spectrum (Fig. 11) is obtained using varying energy loss of α-particles in air corresponding to varying distance between detector and source (Fig. 12);
•No periodic errors found (Fig. 10);
•Results of the developed DAQ system correspond to those by the commercial instrument used;
•Mixed alpha source used (241Am + 244Cm + 239Pu) (Fig. 8);
•Results of the developed DAQ system correspond to those by a commercial instrument used (multichannel analyzer Cicero by Silena);
•Line structure is well visible on both results (Fig. 9);
ResultsResults
AimsAimsThe main goal of this project is to develop a simple R/O (read-out) device for spectroscopy. This device should communicate with analog-to-digital converter (type of Canberra, model 8715 – Fig. 1,2) to gain cheap, easy, and versatile instrument for data acquisition.
HardwareHardware SoftwareSoftware•Control application is based on freeware D2XX direct
drivers [5];
•DLL library included in project allows to use known functions and eliminates the requirement for USB driver development;
•Main assignment of the application is graphical representation of read-out data only during measurement and storing acquired data on hard drive for further processing (Fig. 7);
•During first tests the following capabilities were added
▪ adjustable time of measurement;▪ batch measuring;▪ statistics, etc.
•C++ is chosen as programming language because of its powerful object-oriented features;
•GUI (graphical user interface) is created by Borland VCLs (visual component libraries) [6];
•Widely spread interface – standard USB is available on all contemporary computers;
•Commonly accesible components – no special development needed;
•No auxiliary hardware – e.g., no external supply;
•Open source software – possibility of individual changes;
•Known programming language compatible;
•Plug-in software structure – simple extensions;
Requirements:
Future developmentFuture developmentTo increase efficiency is supposed to:
•A use of a microcontroller multiplexed data bus to utilize only one USB slot maintaining full 13-bit range;
•Revise the sofware and supplement it with more functions for enhanced measuring;
•Development of a multichannel analyzer for spectroscopy coincidence measurement;
AcknowledgementsAcknowledgements ReferencesReferences
Test Test with a semi-continuous spectrumwith a semi-continuous spectrumTest Test with a line spectrumwith a line spectrum
•FTDI (Future Technology Devices International Ltd.) products [1] are employed;
•Modules UMP2 [2] (Fig. 6) pruduced by ASIX s.r.o. [3] based on IC FT245BL are preferred for better manipulation;
•FT245BL [4] transforms LVDS communication on the side of USB to parallel FIFO 8-bit bi-directional data transfer;
•Two integrated circuits FT245BL are used to take advantage of full 13-bit conversion range (Fig. 3, 5);
Fig. 1: A/D converter in crate
Fig. 2: Front panel of converter
≡FTDIFT245BL
≡FTDIFT245BL
A/D
converter
data bus
data bus
hand
shak
esi
gnal
s
USB cable
USB cable
Fig. 6: UMP2 module
Fig. 5: Internal structure
Fig. 4: Block diagram
Fig. 7: Application preview
Source
Vacuum
α-beam
Washer
Detector
Cover
Fig. 8: First experimental set-up
Fig. 9: Spectra of mixed alpha source by (a) the developed system, and (b) the commercial product.
Fig. 3: Read-out device with two USB connectors
•13-bit range
•Frequency rate up-to 50kHz
•USB 2.0 compatible
•USB-powered
[1] http://www.ftdichip.com[2] http://www.asix-tools.com/download/usb/ump2/ump2_en.pdf[3] http://www.asix-tools.com/[4] http://www.ftdichip.com/Documents/DataSheets/DS_FT245BL.pdf[5] http://www.ftdichip.com/Drivers/D2XX.htm[6] http://www.borland.com/index.html
This work has been supported by the Ministry of Education, Youth and Sports of the Czech Republic under the Research Projects MSM6840770029 and 1P04LA212 as well as by Developing Project in the frame of talented student endowment.
Fig. 13: Result of statistical test
Statistical test:
i
ijji nn
121
)1,0(~ )(~ NnnnxnPoni
iiii
• ni – number of counts in
channel i;
• - estimation of
mean value of counts in channel i;
•
Deterministic test:• Test of data-readout
functionality;
• Excelent functionality as illustrated in Fig. 11;
Fig. 11: Semi-continuous spectrum
Difference of distances
Detector
Source
•Signal flags are provided by a convertor (data converted, start new conversion) which are used for hardware control – handshake (Fig. 4). Due to this property, reading is executed as fast as possible
Fig. 10: Example of periodic error
• Result of statistical test (Fig. 13) SummarySummary
Fig. 12: Second experimental set-up
Read-out device assembled and tested.
a
b
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