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Structure and application of equipment assembly for measurement of radon volume activity in houses and soils
0735-245X/91 $3.00 + .00
Nucl. Tracks Radiat. Meas., Vol. 19, Nos 1-4, pp. 431-432, 1991 Int. J. Radiat. Appl. lnstrum., Part D Printed in Great Britain
Pergamon Press plc
STRUCTURE AND APPLICATION OF EQUIPMENT ASSEMBLY FOR MEASUREMENT OF RADON VOLUME ACTIVITY IN HOUSES AND SOILS
VOROBJEV I.B., K R I V O K H A T S K I Y A.S., KRISYUK E.M., NIKOLAEV V.A., PAUTOV V.P,, TERENT'EV M.V. V.G. Khlopin Radium Institute, Roentgen str. I, Leningrad, 197022, USSR Leningrad Radiation Hygiene Institute, Mira str.8, Leningrad, 197101, USSR Pereslavl" Institute "Khimfotoproject", Pereslavl-Zalesskiy, 152140, USSR
ABSTRACT Equipment assembly for measurement of radon volume activity is proposed. Radon concentration values which were measured in some houses of the USSR NorthWestern Region are presented.
KEYWORDS Radon,
cellulose nitrate,
integral passive radiometer,
spark counter
The problem of natural radon is an important global problem of radiation hygiene concerning the population of many regions of the world (Rsdon and its decay products in indoor air, Krisyuk, i989). Revealing of dangerous due to radon regions and large-scale survey of dwellings for radon volume activity are urgent problems. The method and equipment used to solve these problems must satisfy the following requirements: - to provide the possibility of simultaneous survey of thousands of rooms; - to carry out prolonged exposures (up to a month); - to provide the possibility of express reading of information from detectors; - to be handy in operation. These requirements are the most fully met in a measuring assembly b a s e d on alpha track detector enclosed in a special chamber with subsequent automated track counting. The assembly is suitable both for inspection of rooms and for estimation of radon content in soils by placing chambers in special blastholes. The equipment consists of cellulose nitrate alpha track detectors produced at the Institute "Khimfotoproject" (VorobJev et ai.,1989) or LR-II5 type 2, a set of integral passive radon radiometers (IPRR) (Krisyuk,1989), spark track counters of AIST or ISTRA type (Kopohenov et ai.,1989) and appropriate devices for treatment and calibration of detectors. Minimum radon volume activity measured with this method for a month's exposure of radiometer is 15 Bq/m , i.e. ~ 0 , i ram/month. Mean-square error of measurements is --20%. We have carried out inspection of radiation conditions due to radon in three clinics of Leningrad where radon treatment is conducted (see Table 1) and selected survey of dwellings situated in North-Western Region of the USSR. In most surveyd rooms radon volume activity is in the range of 20 - 60 Bq/m 3 but some buildings have been reveled where indoor radon mean concentration are substantially higher than mean values. Fig. 1 shows the distribution of radon volume activity in 43 rooms-of a chosen at random two-storied building situated on the ground with an elevated radon exhalation. Mean value of radon volume activity in this building is 740 Bq/m ~, but there are rooms where radon volume activity of 2000 Bq/mahas been registered. 431
432
I . B . VOROBJEV e¢ aA
Table I. Mean volume activity of radon in air at different points of working rooms of a radon laboratory and baths, Bq/m S. Back- !Inside 1 m from 3 m from on Bath 75 cm above overall ground!workingi working working 45 cm above the bath room box box the bath box ~adon laboratory Clinic 1 Clinic 2
50 30 30
52000 120 30
410 85
3O0
48O
--'m ~I,-- 740 B ~
0
500
50 30
140 30
IO00
I500
~]m=m ~vilW,
2000
~
2500
Ba/= 3
Fig. 1. Distribution of radon volume activity in rooms of a building situated on the ground with elevated radon exhalation. The assembly was operated in a number of regions of the USSR for measurement of radon concentrations in soils in several thousands of measuring points in blast-holes and mines. It was found that IPRH are quite suitable for such measurements protecting detectors from moisture and allowing to get absolute values of radon volume activity. Thus, based on trial operation of the assembly we can note that it represents a convenient and universal m e a n s for wide-scale measurements of radon in air and ground for dosimetric and geophysical purposes.
REFERENCES R~don and Its Decay Products In Indoor Air (1988). Ed. W.W.Nazaroff, A.V.Nero, John Wiley & Sons. Krisyuk E.M.(1989). Radiation background of rooms. Energoizdat. Moskow. Kopohenov V.E, Kozunov A.V., Krivokhatskiy A.S., Nikolaev V.A.(1989). Automated spark counter ISTRA. Nucl. Tracks. Radiat. Meas. 16. N 1, p. 69-70. VorobJev I.B., Gromov A.V., Nikolaev V.A., Pautov V.P., Salina A.G.(1989). Influence of molecular-mass parameters of a polymer on registration characteristics of the detector based on cellulose nitrate. Radiokhimiya, N 5, p. 678-682
Nucl. Tracks Radiat. Meas., Vol. 19, Nos 1-4, pp. 431-432, 1991 Int. J. Radiat. Appl. lnstrum., Part D Printed in Great Britain
Pergamon Press plc
STRUCTURE AND APPLICATION OF EQUIPMENT ASSEMBLY FOR MEASUREMENT OF RADON VOLUME ACTIVITY IN HOUSES AND SOILS
VOROBJEV I.B., K R I V O K H A T S K I Y A.S., KRISYUK E.M., NIKOLAEV V.A., PAUTOV V.P,, TERENT'EV M.V. V.G. Khlopin Radium Institute, Roentgen str. I, Leningrad, 197022, USSR Leningrad Radiation Hygiene Institute, Mira str.8, Leningrad, 197101, USSR Pereslavl" Institute "Khimfotoproject", Pereslavl-Zalesskiy, 152140, USSR
ABSTRACT Equipment assembly for measurement of radon volume activity is proposed. Radon concentration values which were measured in some houses of the USSR NorthWestern Region are presented.
KEYWORDS Radon,
cellulose nitrate,
integral passive radiometer,
spark counter
The problem of natural radon is an important global problem of radiation hygiene concerning the population of many regions of the world (Rsdon and its decay products in indoor air, Krisyuk, i989). Revealing of dangerous due to radon regions and large-scale survey of dwellings for radon volume activity are urgent problems. The method and equipment used to solve these problems must satisfy the following requirements: - to provide the possibility of simultaneous survey of thousands of rooms; - to carry out prolonged exposures (up to a month); - to provide the possibility of express reading of information from detectors; - to be handy in operation. These requirements are the most fully met in a measuring assembly b a s e d on alpha track detector enclosed in a special chamber with subsequent automated track counting. The assembly is suitable both for inspection of rooms and for estimation of radon content in soils by placing chambers in special blastholes. The equipment consists of cellulose nitrate alpha track detectors produced at the Institute "Khimfotoproject" (VorobJev et ai.,1989) or LR-II5 type 2, a set of integral passive radon radiometers (IPRR) (Krisyuk,1989), spark track counters of AIST or ISTRA type (Kopohenov et ai.,1989) and appropriate devices for treatment and calibration of detectors. Minimum radon volume activity measured with this method for a month's exposure of radiometer is 15 Bq/m , i.e. ~ 0 , i ram/month. Mean-square error of measurements is --20%. We have carried out inspection of radiation conditions due to radon in three clinics of Leningrad where radon treatment is conducted (see Table 1) and selected survey of dwellings situated in North-Western Region of the USSR. In most surveyd rooms radon volume activity is in the range of 20 - 60 Bq/m 3 but some buildings have been reveled where indoor radon mean concentration are substantially higher than mean values. Fig. 1 shows the distribution of radon volume activity in 43 rooms-of a chosen at random two-storied building situated on the ground with an elevated radon exhalation. Mean value of radon volume activity in this building is 740 Bq/m ~, but there are rooms where radon volume activity of 2000 Bq/mahas been registered. 431
432
I . B . VOROBJEV e¢ aA
Table I. Mean volume activity of radon in air at different points of working rooms of a radon laboratory and baths, Bq/m S. Back- !Inside 1 m from 3 m from on Bath 75 cm above overall ground!workingi working working 45 cm above the bath room box box the bath box ~adon laboratory Clinic 1 Clinic 2
50 30 30
52000 120 30
410 85
3O0
48O
--'m ~I,-- 740 B ~
0
500
50 30
140 30
IO00
I500
~]m=m ~vilW,
2000
~
2500
Ba/= 3
Fig. 1. Distribution of radon volume activity in rooms of a building situated on the ground with elevated radon exhalation. The assembly was operated in a number of regions of the USSR for measurement of radon concentrations in soils in several thousands of measuring points in blast-holes and mines. It was found that IPRH are quite suitable for such measurements protecting detectors from moisture and allowing to get absolute values of radon volume activity. Thus, based on trial operation of the assembly we can note that it represents a convenient and universal m e a n s for wide-scale measurements of radon in air and ground for dosimetric and geophysical purposes.
REFERENCES R~don and Its Decay Products In Indoor Air (1988). Ed. W.W.Nazaroff, A.V.Nero, John Wiley & Sons. Krisyuk E.M.(1989). Radiation background of rooms. Energoizdat. Moskow. Kopohenov V.E, Kozunov A.V., Krivokhatskiy A.S., Nikolaev V.A.(1989). Automated spark counter ISTRA. Nucl. Tracks. Radiat. Meas. 16. N 1, p. 69-70. VorobJev I.B., Gromov A.V., Nikolaev V.A., Pautov V.P., Salina A.G.(1989). Influence of molecular-mass parameters of a polymer on registration characteristics of the detector based on cellulose nitrate. Radiokhimiya, N 5, p. 678-682