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Thermoluminescent dosimetry at the IFJ Krakow 40 years of experience in TL dosimetry: first LiF crystals for dosimetry were developed in Krakow in 1960s Research on thermoluminescence phenomena Development of new materials, detectors and methods Application of TLDs in various dosimetric measurements Dosimetric service Our activities:
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Thermoluminescent dosimetry at the IFJ Krakow
P. Bilski, B. ObrykINSTITUTE OF NUCLEAR PHYSICS (IFJ), KRAKÓW, POLAND
RADMON, 15 February 2006RADMON, 15 February 2006
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belongs to Polish Academy of Sciences
-founded 1955-450 personnel (180 with Ph.D.)- main research interest: particle physics nuclear physics theoretical physics solid state physics interdisciplinary research-facilities: V-d Graaff (2.5 MeV proton) cyclotron (60 MeV p, 30 MeV d)
Thermoluminescent dosimetry at the IFJ Krakow
P. Bilski, B. ObrykINSTITUTE OF NUCLEAR PHYSICS (IFJ), KRAKÓW, POLAND
RADMON, 15 February 2006RADMON, 15 February 2006
ifjifj
Thermoluminescent dosimetry at the IFJ Krakow
40 years of experience in TL dosimetry:
first LiF crystals for dosimetry were developed in Krakow in 1960s
• Research on thermoluminescence phenomena• Development of new materials, detectors and methods• Application of TLDs in various dosimetric measurements • Dosimetric service
Our activities:
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DOSIMETRIC SERVICE
Laboratory for Personal and Environmental Dosimetry (LADIS)
• Started in 2002
• Accredited according to the ISO/IEC 17025 standard
• 13000 monitored persons or environmental sites
- including 1000 CERN dosimeters
Equipment:
3 Rados DOSACUS automatic readers 3 manual readers Rados dosimeter holders
Calibration: with gamma-rays in the accredited Secondary Standard Calibration Laboratory at the IFJ (LWPD)
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Advantages of TLD
Very small dimensions (standard 4.5x0.9 mm, but even < 1 mm3 is possible)
Passive - no cables, no power supply, etc
Wide range of measured doses
Relatively resistant to environmental factors ( e.g. no influence of electric and magnetic field, vibrations; only elevated temperature is a limiting factor)
Practically unlimited period of measurement (years)
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A human phantom exposed outside of the International
Space Station2003-2006
Over 3000 TLDs from Krakow
2.4 years measuring period2.4 years measuring period
Space experiment MATROSHKA
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LITHIUM FLUORIDEThe most widely used TL detector
Two types: LiF:Mg,Ti (”standard”) MTSLiF:Mg,Cu,P (”high-sensitive”) MCP
Tissue equivalent - atomic number close to tissue (important for X-rays)
Li-6 and Li-7 isotopes make it possible to measure a low-energy neutron signal
10-3 10-2 10-1 100 101 102 103 104 105 106 107 108
100
101
102
103
104
Li-6 Li-7
tota
l cro
ss s
ectio
n, b
neutron energy, eV
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ECAL
Tracker
Pixel
HCAL / MUON
Cavern
1.E-04 1.E-02 1.E+00 1.E+02 1.E+04 1.E+06 1.E+08
Cavern
HCAL / MUON
ECAL
Tracker
Pixel
Dose/Year [Gy]Ch. Ilgner, RADMON, July 2006
DOSE RESPONSE OF TLDsCMS expected dose range
What doses can be measured with LiF TLDs?
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1µGy 1mGy 1Gy 1kGy 1MGy Dose
DOSE RESPONSE OF TLDs
0.1 1 10 100 10000
1
2
LiF:Mg,Ti
SIgn
al /
dose
Dose [Gy]
linearity limit limit of measurementpossibility
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1µGy 1mGy 1Gy 1kGy 1MGy Dose
1µGy 1mGy 1Gy 1kGy 1MGy Dose
DOSE RESPONSE OF TLDs
0,1 1 10 100 10000,0
0,2
0,4
0,6
0,8
1,0limit of measurement
possibility
S
igna
l / d
ose
Dose [Gy]
LiF:Mg,Cu,P - main peak
linearity limit
10-4 10-3 10-2 10-1 100 101 102 103 104
0.0
0.2
0.4
0.6
0.8
1.0
1.2
10-4 10-3 10-2 10-1 100 101 102 103 104
study 1998 study 2004 study 2005
Rel
ativ
e re
spon
se
Dose [Gy]
LiF:Mg,Cu,P
LiF:Mg,Ti
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1µGy 1mGy 1Gy 1kGy 1MGy Dose
1µGy 1mGy 1Gy 1kGy 1MGy Dose
DOSE RESPONSE OF TLDs
LiF:Mg,Cu,P
LiF:Mg,Ti
100 150 200 250 300 350 400 450 500 550 6000,0
0,2
0,4
0,6
0,8
1,0
TL s
igna
l [ar
b. u
nits
]
Temperature, oC
1 kGy
0 – 1 kGy
1 - 50 kGy
50 – 500 kGy
100 150 200 250 300 350 400 450 500 550 6000,0
0,2
0,4
0,6
0,8
1,0
TL s
igna
l [ar
b. u
nits
]
Temperature, oC
1 kGy 10 kGy
100 150 200 250 300 350 400 450 500 550 6000.0
0.2
0.4
0.6
0.8
1.0
TL s
igna
l [ar
b. u
nits
]
Temperature, oC
1 kGy 10 kGy 500 kGy
LiF:Mg,Cu,P thermoluminescence glow-curves
? ? ? ? ?
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DOSE RESPONSE OF TLDs
LiF:Mg,Cu,P
0 – 1 kGy
1 - 50 kGy
50 – 500 kGy
1µGy 1mGy 1Gy 1kGy 1MGy Dose
???
from µGy to MGy => 12 orders of magnitude!
0.01 0.1 1 10 100 1000
0-250 oC 250-350oC 350-550oC
TL s
igna
l [ar
b. u
nits
]
Dose [kGy]
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THE PROPOSED LHC DOSIMETER
One test detector to check the dose level - read out automatically
natLiF:Mg,Ti
One „high-dose detector”, to be read out by special procedure
7LiF:Mg,Cu,P or natLiF:Mg,Cu,P
Two detectors for lower/intermediate doses: e.g. 6LiF/7LiF pair
Its results will decide about choice of readout method for the rest of detectors
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CERF October 2006 RUN
12Gy25Gy28Gy 14Gy
17.5Gy48Gy
45Gy15.5Gy
6 exposures: 4.1 Gy3.6 Gy3.7 Gy3.7 Gy110 Gy
55 Gy
Preliminary results
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CONCLUSIONS
• IFJ Krakow is technically well prepared for dosimetric measurements for LHC
• The newly developed method using LiF:Mg,Cu,P detectors enables measurements far above 1kGy, i.e. the present TLDs’ dose limit
• Further calibrations at the highest doses are planned