Simple pulse microwave waveguide calorimeter with temperature sensor LM 35
The paper presents the construction of a storage-type waveguide calorimeter designed to measure the energy of a sequence of short microwave pulses. The radiation is absorbed by water or ethanol, then the temperature increase is recorded by the LM 35 sensor. When using 14 cm³ of water, the energy mea...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2023
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| Cite this: | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 / A.F. Linnik, D.Yu. Zalesky // Problems of Atomic Science and Technology. — 2023. — № 4. — С. 77-79. — Бібліогр.: 10 назв. — англ. |
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| author | Linnik, A.F. Zalesky, D.Yu. |
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| citation_txt | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 / A.F. Linnik, D.Yu. Zalesky // Problems of Atomic Science and Technology. — 2023. — № 4. — С. 77-79. — Бібліогр.: 10 назв. — англ. |
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| description | The paper presents the construction of a storage-type waveguide calorimeter designed to measure the energy of a sequence of short microwave pulses. The radiation is absorbed by water or ethanol, then the temperature increase is recorded by the LM 35 sensor. When using 14 cm³ of water, the energy measurement range is 3…88 J, and when using ethanol 1.3…40 J. The calorimeter is simple, cheap, and reliable.
Представлена конструкція хвилеводного калориметра накопичувального типу, призначеного для вимірювання енергії послідовності коротких мікрохвильових імпульсів. Випромінювання поглинається водою або етанолом, потім підвищення температури фіксується датчиком LM 35. При використанні 14 cm³ води діапазон вимірювання енергії становить 3…88 Дж, а при використанні етанолу – 1,3…40 Дж. Калориметр простий, дешевий і надійний.
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ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. № 4(146) 77
https://doi.org/10.46813/2023-146-077
SIMPLE PULSE MICROWAVE WAVEGUIDE CALORIMETER
WITH TEMPERATURE SENSOR LM 35
A.F. Linnik, D.Yu. Zalesky
National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine
E-mail: aflinnyk@gmail.com
The paper presents the construction of a storage-type waveguide calorimeter designed to measure the energy of a
sequence of short microwave pulses. The radiation is absorbed by water or ethanol, then the temperature increase is
recorded by the LM 35 sensor. When using 14 cm
3
of water, the energy measurement range is 3…88 J, and when
using ethanol 1.3…40 J. The calorimeter is simple, cheap, and reliable.
PACS: 07.90+c, 65.20-w
INTRODUCTION
Methods of measuring the energy of electromagnetic
oscillations are constantly developing, and new meas-
urement methods and designs of energy meters for elec-
tromagnetic oscillations appear [1 - 3]. But the calori-
metric method of measuring the energy of microwave
radiation remains the most widely used. This method is
characterized by high accuracy and versatility and is
used in the entire radio frequency range to measure the
radiation of both low and high power.
The method is based on the conversion of the energy
of electromagnetic oscillations, absorbed by the coordi-
nated load, into thermal energy and load temperature
rise measurements. In the most common loads, the
working substance is water or ethanol. An increase in
the temperature of the working substance can be regis-
tered directly or indirectly as a change in volume, pres-
sure, or other characteristics.
The calorimeter, proposed in our work, is intended
for measuring the energy of microwave radiation, which
is formed during the conversion of wake waves in a
plasma or in a dielectric structure [4]. Pulses of micro-
wave radiation have a duration of 2 µs. and the repeti-
tion rate is 2 s
-1
.
Our goal was to create a simple and reliable wave-
guide calorimeter of storage type with an exposure time
of 10…20 s and a measurement range from a few joules
to several tens of joules. In addition, the calorimeter
should be located at a distance of about 20 m from the
operator and be resistant to impulses.
In storage-type calorimeters, the increase in the tem-
perature of the working fluid is most often measured by
the increase in the volume of the working fluid in the
measuring capillary tube using resistance sensors [5] or
capacity [6]. But the passage of electric current through
water and its solutions leads to electrolysis and decom-
position of water [7]. In addition, when the liquid in the
measuring tube expands, the effects of uneven wetting
of the tube walls appear. These processes lead to the
need for complex calibration of the calorimeter and
reduce the accuracy of the measurement.
In our work, it is proposed to use the direct method
of measuring the temperature sensor LM 35 to measure
the energy of pulsed microwave radiation, which allows
you to measure minor changes in temperature with a
relative accuracy of no worse than 0.05°C.
The direct method of temperature measurement in
microwave oscillation calorimeters is quite widely used
[8, 9], but the production of previously proposed calo-
rimeters was quite complicated and expensive. Each
calorimeter required a separate setup and calibration
Our goal was to design and manufacture a calorime-
ter that did not require complex or expensive parts, its
application would not require additional setup or cali-
bration and would be suitable for measuring microwave
energy from a few joules to several tens of joules over a
wide frequency range. We believe such a calorimeter
can be made using the LM 35 temperature sensor.
The absorption coefficient of the rf calorimeter is
not worse than α ≥ 0.9. Operating frequency range
Δf = 2…20 GHz.
1. CALORIMETER WITH TEMPERATURE
SENSOR LM 35
1.1. PARAMETERS OF THE LM 35 SENSOR
The energy of electromagnetic oscillations measured
by the calorimeter is defined as E = m·c·ΔT (where m is
the mass of the working fluid, c is the specific heat
capacity of the working fluid, ΔT is the temperature
change of the working fluid under the influence of radi-
ation). To measure the absorbed energy, a non-absolute
temperature value, and the knowledge of the tempera-
ture change when a certain energy is absorbed the accu-
racy of determining the temperature change primarily
depends on the linearity of the temperature sensor.
The LM 35 temperature sensor has sufficient lineari-
ty for our measurements.
This integrated silicon sensor includes a thermosensi-
tive element a primary converter and a signal pro-
cessing circuit made on a single crystal. The output volt-
age of the LM 35 sensor is proportional to the Celsius
temperature scale and is 10 mV/°C. At a temperature of
25 degrees, this sensor has an output voltage of 250 mV,
and at 100 degrees, an output voltage of 1.0 V [10].
From the graph presented in Fig. 1, taken from the
manufacturer's manual for LM35 and LM35A tempera-
ture sensors, it can be seen that the minimum error of
the measured temperature value in the middle of the
operating range of the sensor corresponding to 25°C is 1
and 0.5°C, and at the edges of the range it is 1.5 and
1°C.
These graphs are valid for measuring the absolute
value of temperature. However, in our measurements it
78 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. № 4(146)
is not required to obtain a particularly accurate absolute
temperature value, but rather high sensitivity of the
sensor is required, which is ensured by the high linearity
of the LM35 sensor the dependence of the output
voltage on temperature, in a narrow temperature range
ΔT ~ 2°C at 18…28°C.
Fig. 1. Dependence of temperature measurement
error on temperature
The high linearity of the LM35 sensor is illustrated
by the dependence shown in Fig. 2.
Fig. 2. Dependence of the output voltage of the LM 35
temperature sensor
1.2. CONSTRUCTION OF THE CALORIMETER
We have produced a calorimeter with a three-
centimeter wavelength range placed in a circular cross-
section waveguide. The E01-type wave excitation is
assumed. A calorimeter without external thermal insula-
tion and a temperature sensor are shown in Fig. 3.
Calibration of the calorimeter using an internal heat-
er showed that the sensor detects changes in the temper-
ature of the working fluid by 0.01°C (the output voltage
changes by 0.1 mV). But at the same time, the time to
establish equilibrium increases, and nonlinearity is ob-
served when the temperature increases by 2…3°C.
During the successive absorption of 3 J of energy by
the calorimeter with 14 cm
3
of water as the working
fluid, the sensor recorded a linear increase in tempera-
ture by 0.05°C (0.5 mV the output voltage changes).
Linearity was observed when heated by at least 2°C.
Good linearity was also observed when ethanol was
used as the working fluid.
Fig. 3. Waveguide calorimeter: 1 calorimeter casing
without thermal insulation; 2 temperature sensor
LM 35 in a protective tube
As a result of the calibration, it was determined that
the calorimeter with 14 cm
3
of water as the working
fluid has an energy measurement range from 3 to 88 J, if
the increase in water temperature is limited to 1.5°С.
For a calorimeter with 14 cm
3
of ethanol (11 g), due to
the lower specific heat capacity of ethanol, a tempera-
ture increase of 0.05°C occurs with the absorption of
1.3 J of energy, and an increase in the temperature of
ethanol by 1.5°C corresponds to the absorption of 40 J
of energy.
A special feature of the calorimeter is that it is pos-
sible to make several independent measurements in a
row, only noting the initial and final temperatures at
each measurement without waiting for equilibrium to be
established. Of course, the total increase in temperature
should not exceed 1.5°C. The temperature sensor con-
nection diagram is shown in Fig. 4.
Fig. 4. Connection diagram of the LM 35
temperature sensor
In our case, a battery with a voltage of 9 V was used
for power. The calorimeter was connected to the output
voltage meter with a coaxial cable about 20 m long. The
output voltage was measured by a BT-39C tester.
The calorimeter was tested using a pulse generator
with an MI-30 magnetron at an electromagnetic pulse
duration of 2 µs and a reference frequency of 2 s
-1
, a
linear increase in the absorbed energy was observed
throughout the entire measurement range.
CONCLUSIONS
A calorimeter of a sequence of short pulses of elec-
tromagnetic oscillations was manufactured and tested.
The calorimeter is placed in a circular cross-section
waveguide. Water or ethanol is used as a working sub-
stance. The direct measurement of the temperature in-
crease of the working fluid by a precision temperature
sensor LM 35 with an integrated circuit and a linear
output voltage was used. Preliminary calibration
ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. № 4(146) 79
showed its sufficient linearity when measured with a
relative accuracy of 0.05°С when the temperature of the
working fluid changes by 1.5°C. The calorimeter with
14 cm
3
of water as the working fluid has an energy
measurement range from 3 to 88 J. The energy meas-
urement range for ethanol ranges from 1.3 to 40 J.
The absorption coefficient is α ≥0.9. The range of
operating frequencies: 2…20 GHz.
The range of energy measurement can be signifi-
cantly expanded by using a different volume of the
working fluid and in other wavelength ranges, provided
that the wave resistances of the radiation source and the
calorimeter match.
REFERENCES
1. T.P. Crowley, E.A. Donley, and T.P. Heavner. Quan-
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2. M. Kinoshita, K. Shimaoka, K. Komiyama. Atomic
Microwave Power Standard Based on the Rabi Fre-
quency // IEEE Transactions on Instrumentation and
Measurement. 2011, v. 60, № 7, p. 2696-2701.
3. C. Dietlein, Z. Popovic, E.N. Grossman. Aqueous
Blackbody Calibration Source for Millimeter-
wave/terahertz Metrology // Applied Optics. 2008,
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4. A.F. Linnik, I.N. Onishchenko, V.I. Pristupa,
G.V. Sotnikov, et al. Excitation of the repetition fre-
quency harmonics of electron bunches at the injec-
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5. L.M. Earley, W.P. Ballard, L.D. Rooze. Measure-
ment of RF energy // Rev. Sci. Instrum. 1986, v. 57,
№ 9, p. 2359-2364.
6. A.L. Lisichkin, E.V. Nesterov. Waveguide calorime-
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7. R.B Mccleskey, Darrell K. Nordstrom. Electrical
conductivity of natural waters // Applied Geochemis-
try. 26:S227-S229 2011.
8. Cuccurullo, G. Berardi, P.G. Carfagna, et al. Infra-
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// Infrared Phys. Technol. 2002, v. 43, p. 145-150.
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p. 1-23.
Article received 21.06.2023
ПРОСТИЙ ХВИЛЕВОДНИЙ КАЛОРИМЕТР ІМПУЛЬСНОГО МІКРОХВИЛЕВОГО
ВИПРОМІНЮВАННЯ З ТЕРМОДАТЧИКОМ LM 35
А.Ф. Лінник, Д.Ю. Залеський
Представлена конструкція хвилевідного калориметра накопичувального типу, призначеного для вимірю-
вання енергії послідовності коротких мікрохвильових імпульсів. Випромінювання поглинається водою або
етанолом, потім підвищення температури фіксується датчиком LM 35. При використанні 14 см
3
води діапа-
зон вимірювання енергії становить 3…88 Дж, а при використанні етанолу – 1,3...40 Дж. Калориметр прос-
тий, дешевий і надійний.
https://www.researchgate.net/profile/Richard-Mccleskey
https://www.researchgate.net/profile/Darrell-Nordstrom
https://www.researchgate.net/journal/Applied-Geochemistry-0883-2927
https://www.researchgate.net/journal/Applied-Geochemistry-0883-2927
https://link.springer.com/article/10.1007/s11018-021-01954-w#auth-B__A_-Lapshinov
https://link.springer.com/journal/11018
https://link.springer.com/journal/11018
|
| id | nasplib_isofts_kiev_ua-123456789-196178 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-02T07:16:10Z |
| publishDate | 2023 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Linnik, A.F. Zalesky, D.Yu. 2023-12-11T11:52:59Z 2023-12-11T11:52:59Z 2023 Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 / A.F. Linnik, D.Yu. Zalesky // Problems of Atomic Science and Technology. — 2023. — № 4. — С. 77-79. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS: 07.90+c, 65.20-w DOI: https://doi.org/10.46813/2023-146-077 https://nasplib.isofts.kiev.ua/handle/123456789/196178 The paper presents the construction of a storage-type waveguide calorimeter designed to measure the energy of a sequence of short microwave pulses. The radiation is absorbed by water or ethanol, then the temperature increase is recorded by the LM 35 sensor. When using 14 cm³ of water, the energy measurement range is 3…88 J, and when using ethanol 1.3…40 J. The calorimeter is simple, cheap, and reliable. Представлена конструкція хвилеводного калориметра накопичувального типу, призначеного для вимірювання енергії послідовності коротких мікрохвильових імпульсів. Випромінювання поглинається водою або етанолом, потім підвищення температури фіксується датчиком LM 35. При використанні 14 cm³ води діапазон вимірювання енергії становить 3…88 Дж, а при використанні етанолу – 1,3…40 Дж. Калориметр простий, дешевий і надійний. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Problems of Atomic Science and Technology New methods of charged particles acceleration Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 Простий хвилеводний калориметр імпульсного мікрохвилевого випромінювання з термодатчиком LM 35 Article published earlier |
| spellingShingle | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 Linnik, A.F. Zalesky, D.Yu. New methods of charged particles acceleration |
| title | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 |
| title_alt | Простий хвилеводний калориметр імпульсного мікрохвилевого випромінювання з термодатчиком LM 35 |
| title_full | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 |
| title_fullStr | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 |
| title_full_unstemmed | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 |
| title_short | Simple pulse microwave waveguide calorimeter with temperature sensor LM 35 |
| title_sort | simple pulse microwave waveguide calorimeter with temperature sensor lm 35 |
| topic | New methods of charged particles acceleration |
| topic_facet | New methods of charged particles acceleration |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/196178 |
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