Warszawa, July 3rd 2006 1

Measurements of natural radioactivity in European underground labs within the

ILIAS project

Jan Kisiel

Institute of Physics, University of Silesia, Katowice, Poland(kisielj@us.edu.pl)

Warszawa, July 3rd 2006 2

ILIAS (http://ilias.in2p3.fr/ilias_site/ilias.htm)

• „is an Integrated Infrastructure Initiative that has pulled together all of Europe’s leading infrastructures in Astroparticle Physics”

• „results from a consultation of the community and an internal reviwe process throught ApPEC”

• 20 participants + many non contactor institutions• Three scientific poles:

- Physics in deep Underground laboratories (Gran Sasso, Modane, Canfranc and Boulby)

1 Transnational access activity

3 Networking activities (Deep Underground Science Laboratories, Direct dark matter detection, Search on double beta decay)

2 Joint research activities (Low Background Techniques for Deep Underground Science, Integrated double-beta-decay European Activities)

- Gravitational wave detection

- Theoretical astroparticle physics

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What have been done?

• Gran Sasso Lab. (December 2004):

in-situ measurements, radon emission from the surface, water samples measurements,

• Boulby Lab. (August 2005):

in-situ measurements, radon emission from the surface,

rock samples measurements,• Sieroszowice/Poland, salt chamber:

in-situ measurements, radon emission from the surface,

rock samples measurements.

Warszawa, July 3rd 2006 4

6-17.12. 2004 r.

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Sample1 10 2 9 3 8

Bq/dm3 6.1 ± 0.4 6.5 ± 0.4 9.3 ± 0.5 9.4 ± 0.5 4.4 ± 0.3 4.3 ± 0.3

Sample4 7 5 6 11 12

Bq/dm3 11.4 ± 0.6 10.2 ± 0.5 5.8 ± 0.4 6.0 ± 0.5 5.0 ± 0.4 5.4 ± 0.4

Samples 1-10, 2-9, … were taken in the same place with slightly different methods (radan mobility!) – results are consistent

LNGS measurements, Dec’2004 – cont.

222Rn concentration in the water

Liquid scintilator method (measured with Wallac 1414 WinSpectral liquid sintillation Counter, in Katowice), 12 measurements – see map)

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LNGS, Dec’2004: map of water samples measurements

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222Rn concentration in the air

HALL B

point 1 2 3 4 5 6

Bq/m3 170.4 ± 5.0 174.0 ± 5.0 189.6 ± 5.2 193.2 ± 5.3 297.6 ± 7.7 194.4 ± 5.3

HALL A HALL C

point 7 8 9 10 11 12

Bq/m3 189.6 ± 5.2 187.2 ± 5.2 160.8 ± 4.8 249.6 ± 7.0 246.0 ± 6.9 324.0 ± 8.1

LNGS measurements, Dec’2004 – cont.

Pico-Rad method (Insta-Fluor scinitilator, activate carbon, 48h exposure, 12 mesurements in Halls A, B and C)

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In situ measurements:

• HPGe detector (EG&G ORTEC):

- 30% relative efficiency,

- crystal length 59mm and diameter 58.6mm,

- resolution: 0.67keV at 122keV and 1.73keV at 1.33MeV• M-1 B32 (ORTEC) software for the determination of

radioisotope activity• M-1 geometry: detector mounted 1m above the surface,

gamma emitters recorded from the area in a radius of 10m to a depth of about 30cm (depending on ground and photon enregy)

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Sieroszowice: KGHM copper mine with large (15x15x100m) salt coverns at about 1000m underground – possible location of an underground low

background laboratory in Poland

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0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

0 500 1000 1500 2000 2500

energy [keV]

CP

S

Gran Sasso

Sieroszowice

Boulby

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Net Count Rate [cps] – in situ mesurements

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

0 500 1000 1500 2000 2500

energy [keV]

CP

S

Gran Sasso

Sieroszowice

Boulby

Peak Peak Peak

Bi214-609 keV (Ra226)

Ac228-911 keV

(Th232)K40 - 1460 keV

Gran Sasso 0.487 ± 0.002 0.048 ± 0.003 0.268 ± 0.002

Boulby 0.068 ± 0.002 0.016 ± 0.001 0.262 ± 0.002

Sieroszowice 0.038 ± 0.003 0.006 ± 0.001 0.020 ± 0.003

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Energy [keV] Gran Sasso Boulby Sieroszowice

50-2700 57.68 (0.05) 17.00 (0.01) 2.30 (0.02)

In situ measurements: GS, Boulby, SieroszowiceIntegral background counting rates

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226Ra

Bq/kg

214Pb

Bq/kg (226Ra)

214Bi

Bq/kg(226Ra)

212Pb

Bq/kg(232Th)

228Ac

Bq/kg(232Th)

40K

Bq/kg

Gran Sasso 35 ± 3 32 ± 1 29 ± 1 7.9 ± 0.2 7.2 ± 0.5 94 ± 1

Boulby < 8 5.3 ± 1.8 4.5 ± 1.2 2.1 ± 0.2 2.6 ± 0.8 89.8 ± 1.3

Sieroszowice < 8 4.2 ± 2.3 2.5 ± 0.9 0.8 ± 0.4 0.7 ± 0.3 9.2 ± 1.7

In situ measurements: GS, Boubly and Sieroszowice

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Radon 222Rn measurements in Boulby:

• Durridge RAD7 detector has been used in its sniff mode:

- looks at the 6MeV alpha particles from the 218Po decay,

- variations of radon emission has been monitored by using 48-hours protocol, 1 hour intervals,

- checks of „internal humidity” (detector works correctly if internal humidity < 10%)

- mesurements in 4 points: 3 in JIF area + 1 in H area.

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BOX "2" - start 5.08.05 13:04 stop 7.08.05 13:04

0

1

2

3

4

5

6

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

cycle

Bq

/m3

BOX "2" - start 5.08.05 13:04 stop 7.08.05 13:04

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

cycle

tem

p.

; in

tern

al

r.h

um

.

temp.[°C]

internal r.hum.[%]

Radon measurements: Boulby 2005

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Radon measurements in Boulby: results

• Mean (from 48 hours measurement) values:

- H area: 2.3±1.7Bq/m3

- JIF area 1 (Box2): 2.5±1.4Bq/m3

- JIF area 2 (transport hall): 4.2±1.9Bq/m3

- JIF area 3 (main lab): 2.5±1.9Bq/m3

• Conclusions:

- mean values are „practically” the same

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Future plans (2006):

• 2 in-situ measurements in 2006 (Modane, Boulby and Canfranc):- use two (not one!) portable detectors,

- HPGe detector (EG&G ORTEC) the „old” one,

- GX3020 (Canberra Industries): possibility of measurements in different geometries!, with the minimum detectable activity about 0.1Bq/kg,

- radon emission measurements,

- rock and/or water samples measurements