Radoonitõrjekeskus Teie:
Kasesalu 12,
Saue, 76505 Meie: 11.03.2019 nr 10-3/19-49
Harju maakond
eK, eU, eTh j Rn võrdlusmõõtmise protokoll nr 1
8. märtsil käesoleval aastal toimus Radoonitõrjekeskuse ja Eesti Geoloogiateenistuse gamma-
spektromeetrite ja emanomeetrite võrdlusmõõtmine Eesti Geoloogiakeskuse poolt Tallinnas
Kadaka tee 82 garaaži keldrisse rajatud etalonil (*Petersell jt. 2012).
Võrreldavad instrumendid ja nende olulisemad parameetrid:
Gammaspektromeetrid ja nende parameetrid:
Radoonitõrjekeskus: GR-320 Portable gamma ray spectrometer, Detector model GPX-21A,
valmistajatehas SAIC Exploranium.
Tundlikkus: eU – 0,2 ppm; eTh – 0,5 ppm, eK – 0,1%, 300-sekundilise mõõtmisintervalli puhul.
Eesti Geoloogiateenistus: GT-40 – Multipurpose Gamma Centre, Detektor: NaI/Tl
76 x 76 mm, 345 cm3 koos bi-alkali PMT-ga.
Tundlikkus on: eU – 0,9 ppm; eTh – 1,5 ppm, eK – 0,3%, 300-sekundilise mõõtmisintervalli
puhul.
Emanomeetrid ja nende parameetrid:
Radoonitõrjekeskus: Markus 10 ser. nr 1807 ja Markus 10 ser. nr 0618. Detektor: Ortec Ultra
Silicon, instr. ser. nr 1807 täpsus: 2,2%, instrument ser. nr 0618 täpsus: 2,9%.
Eesti Geoloogiateenistus: Markus 10 ser. nr 1307. Detektor: Ortec Ultra Silicon, instrumendi
täpsus: 1,2%.
* Metoodilises juhendis (Petersell jt, 2012) on eK, eU ja eTh ning Rn-sisaldused ümber
arvutatud etaloni pealispinna tasandile. Käesoleva protokolli tabelites ja graafikutel on esitatud
etaloni süvendites ja emanomeetri mõõtmistorus otsemõõdetud tulemused.
Fr. R. Kreutzwaldi 5 / 44314 Rakvere /
[email protected] / www.egt.ee
Registrikood 77000387
Tabel 1. Radoonitõrjekeskuse ja Eesti Geoloogiateenistuse gammaspektromeetrite võrdlus-
mõõtmise tulemused.
Gammaspektromeeter eK eU eTh
Etaloni keskel % ppm ppm
GR-320 4,5 21,0 7,4
GT-40 2,35 17,0 8,6
Etaloni nurgas
GR-320 4,3 20,9 7,3
GT-40 2,38 16,9 8,3
2016. aasta keskmine
GT-40 2,5 16,2 7,6
Tabel 2. Radoonitõrjekeskuse emanomeetrite Markus 10 ser. nr 1807 ja ser. nr 0618 ning Eesti
Geoloogiateenistuse emanomeetri Markus 10 ser. nr 1307 mõõtmistulemuste võrdlus.
Emanomeetrid Markus 10, 1807 Markus 10, 0618 Markus 10, 1307
Etalonil kBq/m3 kBq/m3 kBq/m3
38,1 37 37
Gammaspektromeetri GT-40 mõõtmiste aegrida etaloni keskel
20
18
16
14
12
10
8
6
4 eU, ppm
2
0 eTh, ppm
Joonis 1. EGT gammaspektromeetri mõõtmiste aegrida etaloni keskmises mõõtmispunktis.
2 (3)
Gammaspektromeetri GT-40 mõõtmiste aegrida etaloni nurgas
20
18
16
14
12
10
8
6 eU, ppm
4
2 Th, ppm
0
Joonis 2. EGT gammaspektromeetri mõõtmiste aegrida etaloni nurga asuvas mõõtmispunktis.
Lisa: Protocol on the assessment of comparison measurement of radon (222Rn) activity
concentration in soil gas at reference sites Cetyne and Buk, Czech Republic, in 2018.
Viide
Petersell, V., Täht-Kok, K., Štokalenko, M., Talpas, A., Jüriado, K. 2012. Pinnase radoonisisal-
duse ja looduskiirguse mõõtmise metoodilise juhendi maketi koostamine ning aparatuuri
kontrollimise tugietaloni rajamine. Tallinn, EGT fond.
Krista Täht-Kok
Vanemgeoloog
[email protected]
3 (3)
Lisa 1
Charles University, Faculty of Science
Institute of Hydrogeology, Engineering Geology and Applied Geophysics
Department of Applied Geophysics
128 43 Praha 2, Albertov 6, Czech Republic
Protocol on the assessment of comparison measurement of radon (222Rn) activity concentration in
soil gas at reference sites Cetyne and Buk, Czech Republic, in 2018
Organization: Geological Survey of Estonia
Fr. R. Kreutzwaldi 5
44314 Rakvere
Code: A05
Date : 17.09.2018 Instruments: Markus 10, Serial No. 1307
Denotation: cA – radon activity concentration, expressed in kBq/m3
t – argument of Student distribution
Test 1 - Test of differences in cA determined by the organization and the group at single
stations of two reference sites
A difference between cA-data reported by the organization and medians of cA-data reported by all
organizations in the group, including the administrator, is tested at each station. The difference is
significant, if the computed interval of confidence does not include zero. Level of significance α = 1 %.
Reference site Interval of confidence Quotient of data outside the interval of conf
Cetyne < -14314 ; 9.914 > 0/6
Buk < -19.232 ; 11.617 > 1/7
Test 2 – Linear regression and correlation of cA data determined by organization and the
group at single stations of two reference sites
Linear regression y = a + bx defines the dependence between cA-data reported by the organization, (y), and
medians of cA-data, (x), reported by all organizations in the group at single stations. An ideal case of data
agreement is a = 0, and b = 1. This presumption is rejected if computed t-value is larger than critical
t-value. Level of significance α = 1 %.
Parameter Computed t-value Critical t-value Coefficient of correlation
a = 1.203 0.288
2.878 0.968
b = 0.934 1.094
Geological Survey of Estonia 1
Test 3 – Test of differences between mean of cA-data reported by the organization at the
reference site and means of cA-data in the database of respective reference site
Means of cA-data from single reference sites are tested by test criterion R1/R2. R1 is a ratio of a mean of
cA-data estimated by the organization to a mean of cA-data estimated by the administrator at given
reference site on the same day. R2 is an arithmetical average of R1 values computed from measurements
of all successful organizations since the beginning of measurements at given reference site (the year
2000). Computation of the ratio R1 eliminates temporal climatic variations of cA at the reference site.
Ratio R1/R2 is independent of absolute cA-values estimated by the administrator. A relative deviation ± 30
% is admissible for the test criterion R1/R2 from ideal value equal to one. Thus, admissible R1/R2 values
for each reference site are within the interval < 0.7; 1.3 >.
Reference site Ratio R1 Ratio R1 / R2
Cetyně 0.887 0.967
Buk 0.970 1.030
Average value 0.999
Conclusions
Test No.1 and test No. 2 (orientation tests based on the comparison with the group) show for the level of
significance α = 1 % a very good agreement of your cA-data to cA-data of the group of 23
organizations participating in comparison measurement on the same day. Test No. 3 (the decisive test
based on comparison with the databases of radon reference sites) shows very good agreement of your
resultant mean of radon data at each reference site in comparison with radon data of all successful
organizations (N = 271) which measured at radon reference sites since the year 2000 and form a database.
After the decisive test No. 3, resultant R1/R2 data fulfil the test criteria and your estimates of radon in
soil gas are very well acceptable for radon risk mapping.
The international radon comparison measurement at radon reference sites in the Czech Republic has been
performed in the frame of the 14th Workshop on Geological Aspects of Radon Risk Mapping, 17 - 20
September 2018, Prague.
Date: 15 November 2018
Evaluated by Prof. RNDr. M. Matolin, DrSc.
Charles University, Faculty of Science