Radiation Science and Technology
2015; 1(1): 1-5
Published online July 16, 2015 (http://www.sciencepublishinggroup.com/j/rst)
doi: 10.11648/j.rst.20150101.11
Applying Virtual Oscilloscope to Signal Measurements in
Scintillation Detectors
Gozde Tektas*, Cuneyt Celiktas
Ege University, Faculty of Science, Physics Department, Bornova, Izmir, Turkey
Email address:
gozdetektas90@hotmail.com (G. Tektas)
To cite this article:
Gozde Tektas, Cuneyt Celiktas. Applying Virtual Oscilloscope to Signal Measurements in Scintillation Detectors. Radiation Science and
Technology. Vol. 1, No. 1, 2015, pp. 1-5.doi: 10.11648/j.rst.20150101.11
Abstract: A virtual oscilloscope was designed by using the LabVIEW software. Signals supplied by a pulse generator and
background radiation signals from a NaI(Tl) scintillation detector were displayed in a real and a virtual oscilloscope,
respectively. Amplitude, maximum voltage, rise time and fall time values through the oscilloscopes for both type signals were
measured. They were acquired in different time/div. values to test and compare their performances. Obtained results and the
signal shapes from them were meticulously compared. It was observed that they were highly comparable to each other. Results
indicate that the developed virtual oscilloscope would reliably be able to be used for data acquisition as well as a real
oscilloscope.
Keywords: NaI(Tl) Detectors, LabVIEW Software, Virtual Oscilloscope and GPIB
1. Introduction
LabVIEW software is one of the virtual instrumentation
software platforms. LabVIEW expanded as Laboratory
Virtual Instrumentation Engineering Workbench. It provides
an easy-to-use application development environment
designed specifically with the needs of engineers and
scientists. It is a powerful graphical development
environment for signal acquisition, measurement analysis
and data presentation [1].
The new way in the design of computer-based
measurement systems can be seen in the use of up-to-date
measurement, control and testing systems based on reliable
devices. Digital signal processing (DSP) is used to replace
conventional analog systems [2]. The virtual instrumentation
technique performed in LabVIEW is used for nuclear DSP
system realization [3].
A virtual oscilloscope is composed of two parts in that
hardware and software. The hardware includes a general
computer and a data acquisition (DAQ) device [4]. The DAQ
devices typically connect directly to the computer’s internal
bus through a plug-in slot. Some DAQ devices are external
and connected to the computer via serial, GPIB (General
Purpose Interface Bus) or Ethernet ports [5]. GPIB facilitates
the communication between computer and instrument. It is
simply the means by which computers and instrument
transfer data. Its purpose is to provide computer control of
test and measurement instrument [6]. Their software include
their driver programs also [4].
An oscilloscope is a device for recording and visualizing
the instantaneous value of alternating voltage [7]. It can be
used in order that amplitude, maximum voltage, rise time
and fall time values of a signal are determined. Amplitude is
a difference between max. and min. voltage values of a
signal. Maximum voltage is a value of positive peak voltage
[8]. Rise time is the passed time to rise from 10 to 90% of
the signal amplitude. Fall time is the passed time to fall from
90 to10% of the signal amplitude [9].
A NaI(Tl) scintillation detector is widely used to particle
detection in nuclear physics. The scintillation can be
converted into electrical pulses which can be analyzed and
counted electronically to give information concerning the
incident radiation. A preamplifier amplifies its input signal
from a detector by filtering it from the electronic noise
together with the impedence matching. A main amplifier
amplifies the output of the preamplifier and shapes it to a
convenient form for further processing [9].
A multifunctional virtual oscilloscope was designed by
Gong and Zhou using LabVIEW software [4]. A virtual
oscilloscope was designed with LabVIEW by D. ShengLi et
al. Voltage and time parameters were determined from a
signal generator to design the test signals by ShengLi et al.
[10].
In this study, a generator signal was compared with a real
2
Gozde Tektas and Cuneyt CeliktasApplying Virtual Oscilloscope to Signal Measurements in Scintillation Detectors.
oscilloscope and a virtual oscilloscope developed with
LabVIEW. The quantities containing voltage and time values
of the signal and the signal shapes were compared with each
other. These processes were repeated for the background
signal from a NaI(Tl) scintillation detector.
2. Materials and Methods
In this work, a GW Instek Model 2204 oscilloscope and a
pulse generator (Ortec 419) as a signal source were used.
The virtual oscilloscope was operated in a desktop PC by
generating a virtual instrument (VI) through LabVIEW. The
connection between the computer and the real oscilloscope
was performed by GPIB interface. Pulse generator output
was first sent to the real oscilloscope, then, the signal was
transferred to the virtual oscilloscope through GPIB cable.
The real oscilloscope’s interface has a USB port, RS232C
and GPIB port. Due to the fact that data transfer rate via
GPIB is fast, GPIB cable was preferred. A block diagram of
the used setup is given in Figure 1.
Figure 1. A block diagram for the measurement of the generator signal.
(DSO: Digital Storage Oscilloscope, VI: Virtual Instrument, GPIB: General
Purpose Interface Bus).
The generator signal was analyzed with different time/div.
values of the real and virtual oscilloscope. During the
measurements, volt/div. adjustment of both oscilloscopes
was set to 500 V. Amplitude, maximum voltage, rise time
and fall time values of the signal were determined. The
measurement was repeated five times for each time/div.
setting. Each quantity was determined between 250.0
and
2.5
time/div. intervals since the entire signal could not be
seen on the scope.
In the second part of the work, background signal from a
Bicron NaI(Tl) scintillation detector (3” x 3”) was displayed
in both of the real and the virtual oscilloscopes. The
spectrometer used for this process composed of a
preamplifier (Ortec 113), an amplifier (Ortec 485) and the
GW Instek 2204 oscilloscope together with the virtual
oscilloscope installed in a PC via GPIB connection were
used. A block diagram is shown in Figure 2.
In the block diagram, the detector output was sent to the
preamplifier. Its output was transmitted to the amplifier, and
its output signal was displayed in the real oscilloscope. The
signal was transferred from the real oscilloscope to the
virtual oscilloscope through GPIB cable. High voltage to the
detector, preamplifier capacitance, amplifier coarse gain and
fine gain adjustments were set to 1000 V, 100 pF, 64 and 10
settings, respectively, thus, the background signal had nearly
same amplitude with the generator signal to compare and test
them easily.
Amplitude, maximum voltage, rise time and fall time
values of the background signal were measured five times
for each time/div. values from both oscilloscopes. Volt/div.
adjustments of the oscilloscopes were kept unchanged. Since
the signal shapes deteriorated in the time/div. under 2.5
and over 50.0 , all measurements were performed between
these time values.
3. Results and Discussion
Amplitude, maximum voltage, rise time and fall time
values for the generator signal and the background signal
were determined from the real and the virtual oscilloscopes.
To test the performance of the virtual oscilloscope signal
measurements were performed at different time/div.
adjustments. All measurements were performed after the
oscilloscopes were stopped.
For the generator signal, time/div. setting was set to
250.0 , 500.0 , 1.0
and 2.5
, respectively. The
comparison between real and virtual oscilloscopes for the
generator signal is given in Tables 1-4. Background signal
from the NaI(Tl) scintillation detector was analyzed for 2.5
, 5.0
, 10.0
, 25.0
and 50.0
time/div.
adjustments. Obtained results from the oscilloscopes are
given with their relative errors in Tables 5-9. Besides, signal
shape comparison for the generator signal for 250.0
time/div. adjustment is shown in Fig. 3. Background signal
shapes from the scintillation detector through both
oscilloscopes are compared in Fig. 4 for 2.5
time/div.
setting.
Table 1. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the generator signal for 250.0
time/div. in the real and
virtual oscilloscope.
1
2
3
4
5
Figure 2. A block diagram for the measurement of NaI (Ti) scintillation
detector background signal. (DT: Detector, HV: High Voltage, PA:
Preamplifier, A: Main Amplifier, DSO: Digital Storage Oscilloscope, VI:
Virtual Instrument, GPIB: General Purpose Interface Bus).
1
2
3
4
5
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.020±0.109
1.400±0.011
1.020±0.109
1.380±0.002
1.240±0.087
1.380±0.002
1.240±0.087
1.380±0.002
1.140±0.007
1.380±0.002
Real Oscilloscope
1.020±0.109
1.400±0.011
1.020±0.109
1.380±0.002
1.240±0.087
1.380±0.002
1.240±0.087
1.380±0.002
1.140±0.007
1.380±0.002
TR ( s)
5.912±0.143
6.182±0.093
7.402±0.086
7.403±0.086
6.908±0.021
TF ( s)
778.500±0.096
813.500±0.049
815.000±0.047
896.000±0.047
964.500±0.115
5.913±0.143
6.182±0.093
7.403±0.086
7.403±0.086
6.909±0.021
778.500±0.096
813.500±0.049
815.000±0.047
896.000±0.047
964.500±0.115
Radiation Science and Technology 2015; 1(1): 1-5
Table 2. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the generator signal for 500.0
time/div. in the real and
virtual oscilloscope.
1
2
3
4
5
1
2
3
4
5
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.340±0.011
1.380±0.011
1.300±0.018
1.340±0.017
1.320±0.003
1.360±0.002
1.340±0.011
1.380±0.011
1.320±0.003
1.360±0.002
Real Oscilloscope
1.340±0.011
1.380±0.011
1.300±0.018
1.340±0.017
1.320±0.003
1.360±0.002
1.340±0.011
1.380±0.011
1.320±0.003
1.360±0.002
1
2
3
4
5
1
2
3
4
5
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.340±0.017
1.380±0.017
1.320±0.003
1.360±0.002
1.220±0.078
1.260±0.076
1.360±0.032
1.400±0.031
1.340±0.017
1.380±0.017
Real Oscilloscope
1.340±0.017
1.380±0.017
1.320±0.003
1.360±0.002
1.220±0.078
1.260±0.076
1.360±0.032
1.400±0.031
1.340±0.017
1.380±0.017
TF ( s)
904.000±0.035
854.900±0.019
869.900±0.002
867.600±0.004
862.900±0.010
1
2
3
4
5
16.000±0.002
16.250±0.018
15.760±0.012
15.760±0.012
16.000±0.002
904.000±0.035
855.000±0.019
870.000±0.002
867.500±0.005
862.900±0.010
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
TF ( s)
897.400±0.045
818.900±0.045
827.300±0.034
905.200±0.054
832.400±0.028
1
2
3
4
5
31.530±0.018
32.490±0.012
32.000±0.003
32.470±0.011
32.000±0.003
897.500±0.045
819.000±0.045
827.200±0.035
905.100±0.054
832.300±0.028
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.120±0.025
1.220±0.049
1.140±0.042
1.180±0.016
1.180±0.074
1.220±0.049
1.000±0.092
1.040±0.115
1.020±0.070
1.140±0.017
Real Oscilloscope
1.120±0.025
1.220±0.049
1.140±0.042
1.180±0.016
1.180±0.074
1.220±0.049
1.000±0.092
1.040±0.115
1.020±0.070
1.140±0.017
TR ( s)
1.275±0.000
1.278±0.001
1.315±0.029
1.296±0.015
1.216±0.049
TF ( s)
7.840±0.115
7.530±0.078
5.900±0.175
7.230±0.040
6.176±0.122
1.275±0.000
1.278±0.001
1.315±0.029
1.296±0.015
1.216±0.049
7.840±0.115
7.530±0.078
5.900±0.175
7.230±0.040
6.176±0.122
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.120±0.250
1.200±0.223
1.700±0.176
1.720±0.146
1.440±0.027
1.520±0.034
1.300±0.076
1.380±0.063
1.440±0.027
1.520±0.034
Real Oscilloscope
1.120±0.250
1.200±0.223
1.700±0.176
1.720±0.146
1.440±0.027
1.520±0.034
1.300±0.076
1.380±0.063
1.440±0.027
1.520±0.034
TR ( s)
1.173±0.034
1.151±0.054
1.279±0.051
1.273±0.046
1.191±0.018
TF ( s)
6.853±0.225
6.983±0.240
4.442±0.194
3.824±0.387
4.421±0.199
1.173±0.034
1.151±0.054
1.280±0.051
1.274±0.047
1.192±0.018
6.853±0.225
6.983±0.240
4.444±0.193
3.825±0.387
4.423±0.199
Table 8. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the background signal for 25.0 time/div. in the real
and virtual oscilloscope.
TR ( s)
79.990±0.003
79.990±0.003
78.780±0.012
79.990±0.003
79.990±0.003
TF ( s)
831.500±0.046
894.300±0.026
819.200±0.062
873.200±0.003
932.800±0.067
1
2
3
4
5
80.000±0.003
80.000±0.003
78.780±0.012
80.000±0.003
80.000±0.003
831.600±0.046
894.200±0.026
819.100±0.062
873.300±0.003
932.800±0.067
1
2
3
4
5
Table 5. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the background signal for 2.5
time/div. in the real and
virtual oscilloscope.
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.700±0.228
1.740±0.216
1.180±0.111
1.200±0.136
1.240±0.058
1.300±0.049
1.320±0.006
1.380±0.011
1.120±0.171
1.200±0.136
Real Oscilloscope
1.700±0.228
1.740±0.216
1.180±0.111
1.200±0.136
1.240±0.058
1.300±0.049
1.320±0.006
1.380±0.011
1.120±0.171
1.200±0.136
Table 7. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and
fall time (TF) values of the background signal for 10.0
time/div in the
real and virtual oscilloscope.
TR ( s)
31.520±0.018
32.490±0.012
32.000±0.003
32.480±0.011
32.000±0.003
Table 4. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the generator signal for 2.5
time/div. in the real and
virtual oscilloscope.
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.300±0.000
1.340±0.000
1.280±0.015
1.320±0.015
1.300±0.000
1.340±0.000
1.300±0.000
1.340±0.000
1.320±0.015
1.360±0.014
Real Oscilloscope
1.300±0.000
1.340±0.000
1.280±0.015
1.320±0.015
1.300±0.000
1.340±0.000
1.300±0.000
1.340±0.000
1.320±0.015
1.360±0.014
Table 6. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the background signal for 5.0
time/div. in the real and
virtual oscilloscope.
TR ( s)
16.000±0.002
16.250±0.018
15.760±0.012
15.760±0.012
16.000±0.002
Table 3. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the generator signal for 1.0
time/div. in the real and
virtual oscilloscope.
3
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.300±0.009
1.400±0.028
1.200±0.093
1.220±0.114
1.240±0.058
1.320±0.030
1.100±0.192
1.140±0.192
1.720±0.237
1.720±0.209
Real Oscilloscope
1.300±0.009
1.400±0.028
1.200±0.093
1.220±0.114
1.240±0.058
1.320±0.030
1.100±0.192
1.140±0.192
1.720±0.237
1.720±0.209
TR ( s)
1.603±0.005
1.582±0.018
1.584±0.017
1.687±0.044
1.600±0.007
TF ( s)
5.406±0.240
6.098±0.099
6.352±0.055
8.250±0.187
7.416±0.095
1.603±0.005
1.583±0.017
1.584±0.017
1.687±0.044
1.600±0.007
5.408±0.240
6.100±0.099
6.357±0.054
8.250±0.187
7.418±0.095
Table 9. Amplitude (Vamp), maximum voltage (Vmax), rise time (TR) and fall
time (TF) values of the background signal for 50.0
time/div. in the real
and virtual oscilloscope.
TR ( s)
1.215±0.002
1.272±0.042
1.315±0.073
1.200±0.015
1.088±0.119
TF ( s)
3.590±0.343
5.240±0.079
5.938±0.187
5.350±0.098
3.992±0.207
1
2
3
4
5
1.215±0.002
1.272±0.042
1.315±0.073
1.200±0.015
1.088±0.119
3.590±0.343
5.240±0.079
5.938±0.187
5.350±0.098
3.992±0.207
1
2
3
4
5
Virtual Oscilloscope
Vamp (V)
Vmax (V)
1.700±0.174
1.700±0.157
1.440±0.025
1.460±0.019
1.160±0.210
1.200±0.193
1.080±0.300
1.160±0.234
1.640±0.143
1.640±0.126
Real Oscilloscope
1.700±0.174
1.700±0.157
1.440±0.025
1.460±0.019
1.160±0.210
1.200±0.193
1.080±0.300
1.160±0.234
1.640±0.143
1.640±0.126
TR ( s)
1.600±0.334
1.719±0.241
1.657±0.288
2.462±0.132
3.236±0.340
TF ( s)
13.960±0.020
15.110±0.057
15.910±0.104
12.750±0.117
13.510±0.054
1.600±0.334
1.719±0.241
1.657±0.288
2.462±0.132
3.236±0.340
13.950±0.020
15.110±0.057
15.910±0.104
12.740±0.117
13.500±0.054
4
Gozde Tektas and Cuneyt CeliktasApplying Virtual Oscilloscope to Signal Measurements in Scintillation Detectors.
(a)
(b)
Figure 3. Generator signal shapes in (a) the virtual and (b) the real oscilloscope for 250.0
(a)
(b)
Figure 4. Background signal shapes in (a) the virtual and (b) the real oscilloscope for 2.5
When compared all results from the oscilloscopes above,
it can be easily realized that voltage values (Vamp and Vmax)
were very close to each other whereas very few differences
on rise time and fall time values have been occurred in some
measurements. Even so, it can be deduced from the overall
results that the measurement performance of the virtual
oscilloscope was quite satisfactory.
4. Conclusions
A signal generator and the background radiation signals
from a NaI(Tl) scintillation detector were separately
analyzed. Amplitude, maximum voltage, rise time and fall
time values of both type signals were determined for
different time/div. adjustments. Obtained values from the
designed virtual oscilloscope were highly comparable to
those of the real oscilloscope as can be seen from tables (1-9).
Also, it was observed that generator and background signals
in both oscilloscopes were similar in shape. Finally, our
designed virtual oscilloscope (VI) showed highly good
performance in comparison with the real one. It was deduced
from the obtained results that the developed virtual
oscilloscope would reliably be able to use for the data
acquisition as well as a real oscilloscope. This helps us to
time/div.
time/div.
analyze many types of detector signals in scintillation
detectors. .
Acknowledgment
This work was supported Scientific Research Foundation
of Ege University under project No. 14 FEN 052.
Additionally, the Authors thank to Dr. Jiri Pechousek for his
precious help.
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