Radiation Education with Radon Detector- Detector Development and Implementation at High School -Tomo Nakajima, Takafumi Niida
University of Tsukuba

11th INTERNATIONAL WORKSHOP on the GEOLOGICAL ASPECTS OF RADON RISK MAPPING3.11 Fukushima Nuclear Power Station Accident

http://photo.tepco.co.jp/

http://ja.wikipedia.org/wiki/

TsunamiDispersion of Cs, I

Meltdown

Hydrogen explosion

Misinformation in Media and Internet

Why such rumor spread??
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Radiation Education in Japan
Japanese don’t have enough knowledge about radiation.

Now education of radiation literacy is regarded as important.

Course of Study

Published by a ministry of education, culture, sports, science and technology

原子核の構成、原子核の崩壊、半減期、核分裂、核融合、原子核反応を扱...learnconstruction and decay of nuclei, a half-life, nuclear

い、質量とエネルギーの等価性にも触れる。例えば、放射線計測、霧箱を用い
fission...For example, a cloud chamber and GM counter are introduced
た 放射線の観察 などを行うことが考えられる。

as radiation detector...

Understanding of Decay ofnuclei, a half life and energyof radiation

Cloud chamber

Geiger-Mueller counter©Hitachi Aloka Medical

3Radon Detector

Criteria as a Teaching Material for Radiation Education① To be able to learn about a half-life and radioactive disintegration.
② To be easy to handle for students and teachers.

+③ To be Safe, low cost and compact.

Active learning program

Purposei) To develop a safe and compact Radon Detector in low cost as ateaching material.
ii) To implement education of radiation literacy with it in physics
club of high school.
iii) To promote student’s ability of treating and understanding
information(data) correctly, and deciding what to do bythemselves through active learning program.

General View of Radon Detector

RadonDetector

α-ray DetectionPreAmp.

ShaperAmp.

Pulse HeightAnalysis

ArduinoData Control

PC

Data Collection

5α-ray Detection
P-I-N Photo Diode for α-ray detection
Reflexible Surface：10mm×10mm

218Po+

218Po+

222Rn

【S3590-09 HAMAMATSU made】

Electrostatic Collection*

Photo Diode（-600V）

to collect cations effectively(The range of α-ray is 2~3cm in air.)214Po+

Collect 218Po and 214Po cations ofdaughter nucleus by electrostatic
field on the surface of Photo Diode*Nucl. Instrum. Methods Phys. Res., A 421 , 1-2 (1999) 334-341

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Pulse Height Analysis
Shaper Amp.
α-rayDetection
PartPreAmp.

CR-RC-RC
circuitComparator
circuitSample andHold circuit④③② gate signal① trigger signal

Input signal...

input signal
信号処理手順① Send trigger signal② Send gate signal③ Send the held pulse
height of the signal④ Send the held pulse
height data to PC

trigger signal

Arduino!"#$%&'()$*gate signal①
gate signal
hold the pulse heightPCData Control

Arduino nanoOp

Data Collection

ecruosenProcessing

8bit microcomputer chip that iscalled ATMEGA328 with 10bit ADC
in circuit board is used.
To able to upload program from PC
to ATMEGA through a USB port

Input and output of digital / analog
signalOnline monitoringCircuit Board

High Voltage Power Supply forElectrostatic Collection

Power SupplyShaper Amp.
Sample & Hold

Pre9 Amp.

Results of Radon Measurement
Object：Radon Gas (gathered from ore)

3.9days

Time：7days

218

Po214

3.8daysPo【Fig.1】

We can measurea half life
by using right equations!!

【Fig.2】
222Rn:

dN1 = −λ1N1dt
218Po: dN = (λ N − λ N )dt
2
1 12 2.....
214Po:

dN4 = (λ3N3 − λ4N4)dt214( Po ~ 214Bi)
10Characteristics of Radon Detector as teaching materialand Effect expected① To be able to measure α-ray energy and a half-life.
② To be able to identify nuclide of a radioactive
element by the measured half-life and energy.
③ Students make detector by themselves.

◉ Promote student’s deeper understanding about radioactive
material by the measurement◉ Promote student’s ability of treating and understanding
information(data) correctly, and deciding what to do by themselves
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The Guidance PlanTarget

Physics Club of High SchoolTime11hoursGuidance Form

Team-Teaching◉Feel that there is radiation around us.
◉Make students more interested in making things by hand.

Object◉Learn and understand correct knowledge of nucleus and radiation.
◉Promote scientific ability to think and expressiveness.
◉Promote student’s ability of treating and understanding information(data) correctly, and deciding what to do by themselves.
① Discussion (theme is the radiation)② Lecture by a teacher③ Making the Radon Detector

Composition ④ Measurement and Data Analysis⑤ Presentation⑥ Discussion※Discuss simply after every class12

Method of Identify Nuclide at High School
How to identify nuclide of a radioactiveelement...

uranium series(MeV)-./,,,① Which nuclide can be observed within measurement
time in terms of a half-life??
② Which energy peak of α-ray can be observed first,lower or higher peak??
③ Students compare the ratio of α-ray energy for 2peaks with the known value.

78/

0$*,,&1

,2*!"($)*%'

34/,2*

B

0$+(5!"($&&*'

36/,2)

34/

2$(9,:

?@/,2)

2$%)=2+>):

B,2+!"($(+(';</,2+!"#$%&'

36/2&$#5

B,%$*5,2)!"%$#+',+$)A

B

2$0,5

At intervals of 20min
20min

40min

60min

80min

100min120minImplementation and QuestionnaireHigh School
It is good...
...To be able to experience many fields such as hardware,
software, data analysis and so on.
...To have opportunity to identify nuclide from decay chain.
...To be able to consider various things from the measured
data.
As to a question that what the most interesting work foryou is, they answered it was soldering of the circuit board,Arduino, data analysis, discussion and so on.

Summer Challenge Project at KEK
It is good...
...To be able to understand radiation measurement
intuitively by making detector.
...To feel a sense of achievement which wrestle frommeasurement to analysis ourselves.

Summary✓We have developed safe and compact radon detector
with low cost as a teaching material for radiation
education.

✓We have implemented radiation education with it inphysics club of high school.Students made it bythemselves and could measure the radon gas with it.

✓Improvement to smaller radon detector is on going.

!
!
kcehC

Our HP URL (Sorry in Japanese...)http://utkhii.px.tsukuba.ac.jp/~radon/
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Thank you for your kind attention.