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tSoienfceandTcchnologyj\?ol5,No. 1 (2015), pp. 33-38
Research tU development of multi - chamiel analyzer used for monitoring and warning radiation equipment
Nguyen Van Sy», Dang Qnang Tlieu, Nguyen TW Bao My Hanoilrradiation Center
Km 12. Route 32. Minh Khai, Bac Tu Uem. HaNoi
*Email: vaRsybn@^iail.com {Received20Jamimy2015, accepted 28 May 2015)
^ L ' S ^ f ^ ' i " ^ ^ ^ " W» paper presents researeh on development of muM-chemel K 0 ^ 6 / n 1 5 ^ : ! t " * " ^ ™ ^ ^ cnviremnenld ladiation eQuipmcn. under Uie project ftlZ; ; ™ • » ° " f i " ^ 8 equipment monitoring and wareing ladiation- T a i s T ^ Z T l T T""^ r " - ^ " •» ' ^ ' " ^ ^ - « ^ ^ a p L o ^ o r a m p l i S
. t ^ Z ^ ^ T : """""'^ ^ ' ' ' " ™"^ "•" * ' ^ " ^ ° » - ' - p u i r i p e d to connecuo Meh stabilitv fc„ I^ eoaverte Mock (ADq m accoidance wiUi tiie actiial conditions, such as e o n v e t , c r i n , o a ^ t i - c h . n n c l a n a l y . e , ( M C ; ) l l r l ^ r " ^ """" "^ ^ ° ^ - ' ° - ^ « Keywords: MuM.channel analy^. Analog-to-dig)Utl converter. Spectroscopy amplifier.
be considered in designed time. In addition, energy consumption is optimized for the system to ensure long-term operation when the electric network not yet
I. DiTRODUCnON The nmlti-channel analyzer system for monitoring and wanting enviromnental radiation equipment, with such requirements:
The device using scintillation detector must have a high sensitivity to measure low dose range. Dose rates are calculated flmmgh spectrum to identify radioactive isotopes.
Equipment must be sable in any environmental conditions so that the device was be equipped the energy calibrated circuit to adjust changing of wide temperature range. The mannfactored device should be enough memory to store data for several days.
To solve above-mentioned requirements, multi-channel analyzer operates accompany with stable spectroscopy ampUfier having digital gain circuit oonoolled by microcontroller. Using the ftst analog-to-digital converter and suitable micro-conttotter should
n . DESIGN AND CONSTRUCTION A. Spectroscopy amplifier block
The universal designed spectioscopy amplifier with the following parameters- amplification pulse signal from the several hundred nullivolts to pulse width 4psec Gaussian shape, amplitude ftom 0 to lOV The microcontroUer can set the digitized gain of amplifier, relying on that the spectta could be automatically calibrated and stabilized.
The spectroscopy ampUfier is required to complete the following fimctions- flie differentiation and pole zero canceUation amplified amplimde, pulse shaping, base-line restore, and mcreased output stiength [1], - ^,*3|, Society and Vietnam Atomic Energy tostitute
RESEARCH ON DE\ ELOP-MENT OF MLLTI - CHANNEL .ANALYZER From The analysis and put forward the
request on the spectroscop\ amplifier the block diagram is shown in Figure !
In this diagram all chips amplifiers are LF356 devices, they are fasi amplifier with JFET high impedance input The digital gain.
set up by a digital-to-analog converter using DAC0808 device, can be adjusted the pulse amplitude up to 50% entrance. The resislois used in the circuit with high precision of 1%
error removal from components
Fig.l. Diagram ofthe spectroscopy amplifier B. Analog to Digital converter block
The designed mnovative analog to digital converter used for the monitonng and warning environmental radiation system are required steady work and fast convertion time, data access updated contmuously ensure accurate alerts and continuously. The requirements of the sysiem are analyzed [2]
> 4000 channel resolution.
> 5-7^sec conversion lime.
> The integral nonlmearity < 0.025%.
> The differential nonlmearity < 1.5%.
To meet the demands posed problem we select and offer solutions designed block- number variation similar to Figure 2.
Anq>iifiei
Setup
Levels Discharge
Micro Controller
Logic Controller
Fig.2. Block diagram ofthe analog-to-digital converter 34
NBUYS) VAN SY, DANG QUANG -THIEU, NGUYH« THI BAO M Y Based on these dijectives and tUa Wock
""MSram we selected IC analog-to^iigital convmer AD74-72 with the fcUowing specifications: 500ns convettioB time, Ite mtegral nonlineanty is ± o,5LSB and liiffeiential nonHnearily is ± ILSB, low
"•"sumption 8,7mW line with sio^e 5V pown supply.
•He using Cypress AN2I3I micro-
"Mralta- fiir acquisition, piocessmg the sP«*nni data and comnnmication with the computer aUows meets flie leqnirenients. The suppHed logic combination using a pmgrammable IC GAU0V8 entiie cycle control, it was programmmg to generate the
<liscretion of the user [2], The logic combination creates flill lifecycle of multi- channel systems analysis,
i n . RESULTS AND DISCUSSION
ASex completing &e design schematic and PCB dicmt diagiam in spectroscopy amplifier block and analog to digital converter block, assendily of one complete cinniit components aiHl multi-channel analyzer as shown in Figure 3,
Condncting caUbration amplifier block we reach to tfie following parameteis [3]:
> An^lifier output amplitude range fiom OV to lOV in die shape of Gaussian pulse with 4ps sfaapping time.
> An^ilification &ctor can be change ftom potentiometers and ftom microcontroller can set the digitized gain fiom 0 to 255, while the coefficient iz changing of 10 units, the channel number win change 20 channels, based on parameteis for flie ddiess flie ptoblem of universal stability.
Fig.3. Diagram final assembly of multi-channel analyzer The fiimware piogram for die
miciucontroUer is written in Keil CSl software tools and user program for inteificing, common data processing and accquisidon conlrol were written m Labvicw; rely on fliis program for us
to survey the parameteis of multi-channel analyzer system.
Survey of integral nonlinear gathers is shown m Figure 4 and plot of linear fimction of the pulse amplimde against die chamiel enttance is presented m flie figure 5,
R£SE.ARCH 0 \ DEN El OPMEN I OF ML LTI - CHANNEL ,'NN,'NLVZER
-^M^
Fig.4. Sun.ey data of integral nonlineanty
Fig.S. Graph jawjoints survey data of integral nonlmearity
Command's misjudging channel function evaluating the differential nonhnearily based o was lit 10 the measured expenmental values
ha\e been the diagram m Figure 5, From the fomiula [4] we calculate the integral nonlineanty ofthe system is'
, . „ . , Admax 0 895
" " • ' ' - ? ; : J ; : ; ; ; ^ » I ™ - : ^ ' i ™ - f 022%
our data sets shown in in Figure 7.
According to our calculation formula [4]
!s the differential nonlineanty ofthe system is DNL% = -
Navg Sui-\e\ of differential nonlineanty data
collection is shown in Figure 6. and we were
IWWVBN VAN SSCHlNG QUANG -THIHJ, NGUYBS IHI BAO MY
Fig.6. Suivey dala of diffenrndal nonlineanty 26200
25200 - 24200 -
o
22200 21200 - 20200 -
0 1000 2000
Channels
3000 4000
1 Thus, we have designed and fabricated a
conqjlete multi-channel analyzer with the following parameters:
> 4000 channels resolution.
> 5jisec conversion time.
> The integral nonlineanty is 0.022%.
> The difTerential nonlineanty is 1.48%
FIg.7. Calculation of differential nonlineanty
rv. CONCLUSION With the optima! choice of components and electronic circuits, along with requirments set out thematic problem has accomplished the following;
RESEARCH ON DEVELOPMENT OF MULTI - CHANNEL AssAi.k^ix.TT D e s i ^ coDstructioD and correction
spectroscopy anq}lifier block performing the anqjUfio* and shq)e of pulse signals from radiation scintillation detector and can set tbe digitized ^tin of amplifier.
Design, construction and correction analog to digital blodc p^onning the convertioQ of tiie pulse si^ial fi:om tiie aiiqilifier output to a distal si^ial for data acquisition, calculation and analysis, along with processing software have been a multi-channel analyzer of stable pCTformanra and fast conversion time.
REFERS^C^..
L\EA-TECIX)C-426; Trebles Nuclear Listruments, 1987.
DuSan Ponikvar; Diptal etectromcs, £ 2001.
Heinz Ron^n; Univrasal An^^^Di^
SCA/MCA, 2006.
DuSan Ponikvan Slovenia, 2001.
Multichannel Anuiw
ACKNOWLEDGMENT We gratefiilly acknowledge the financial support of the project KC.05.16/11-15. We would like to thanks to the Institute of Nuclear Science and Teclmology, Vietnam Atomic Energy Institute and Ministry of Science Technology for their support to implement the project