1
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Americium -241
Alpha foils and sources for smoke detectors
Related Products
Americium-241 (Am-241) alpha particle emitting foil, made by
Detector Technology, is widely used in ionization chamber smoke
detectors (ICSD). The foil combines high integrity of
containment with high emission efficiency.
Detector Technology has a wide-ranging expertise in the design
and construction of ionization chambers, built up over 30 years
of experience in smoke detection. A consultancy service is
offered for the design and/or manufacture of ionization
chambers intended for use both in smoke detection and other
applications.
Detector Technology has over 30 years experience of foil
technology and offers a well established standard product range
of foil mounted in holders.
Regulatory Compliance
Construction
Detector Technology foil meets the regulatory requirements of
most national authorities worldwide.
Detector Technology Am-241 foil has been evaluated and
registered by the US Nuclear Regulatory Commission (NRC).
These registrations are now under the jurisdiction of the
Massachusetts Radiation Control Program. Registrations
tabulated below, are recognized in the US as equivalent to NRC
registrations and so has nationwide validity.
The radioactive material Am-241 emits alpha and low energy Xand γ-radiation. It is incorporated within a gold matrix and
sandwiched between a silver backing and a palladium laminate
face, as illustrated schematically below. The face layer is thick
enough to retain completely the Am-241 but thin enough to allow
efficient emission of the α-radiation.
The shaped foil pieces are then mounted into various holders by
staking, securing between spot welded metal plates or rolling over
the holder edges.
Foil for use in smoke detectors
Detector Technology has developed techniques for producing foil
pieces cleanly, reproducibly and safely, and also for mounting
them into holders. Specialized equipment and appropriately
licensed facilities are essential to both processes. It is strongly
advised that these operations be carried out at our facilities.
US-Model number
Detector Technology offers a standard product range. Certain foil
pieces are also available as indicated. We welcome early
discussions on new customer requirements.
Cross Section
Foil emitting one side only
AMM.1001
Foil emitting from both sides
AMM.1001D
Foil mounted in holder
AMM.1001H
Palladium facing (-2mm)
Active matrix (~1mm)
Silver backing (0.15-0.25mm)
2
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Sources In Holders
X.0868 Holder
It is strongly recommended that customers purchase sources that
are already staked directly into holders by Detector Technology.
This avoids the need for customers to maintain radioactive
facilities for foil handling. Sources in holders pass the statutory
leak tests that are required for sealed sources and they meet the
requirements of regulatory authorities worldwide.
Six standard product examples are illustrated below. Alternative
designs are also available, for which enquiries are welcomed.
Detector Technology has extensive experience of holder design
and manufacture and is pleased to advise on any aspects of
technical performance, safety, quality and service.
Ø 4.9
1.3
0.4
Ø 8.9
Dimensions in mm
Several staking and sealing patterns are available. These comprise
5 or 6-point staking patterns or holders that are continuously
crimped around the circumference of the source and holder.
Activity
A continuous crimp design provides added strength and integrity
by continuously sealing the foil around the cut active edge.
Activity tolerance
Product code
18.5kBq (0.5mCi)
±20%
AMMK7648
29.6kBq (0.8mCi)
±20%
AMMK1235
Closure: 6-point stake or extended width crimp pattern
Quality control: Wipe test I
Safety performance rating: ANSI/ISO C64444
Recommended working life: 10 years
X.0849 Holder
X.0869 Holder
Ø 6.4
1.5
1.6
Ø 4.9
1.3
Ø 3.2
0.4
Dimensions in mm
Ø 6.3
Activity
Activity tolerance
Dimensions in mm
Product code
18.5kBq (0.5mCi)
±20%
AMMK7540
29.6kBq (0.8mCi)
±20%
AMMK5597
Activity
Closure: 6-point stake or extended width crimp pattern
Quality control: Wipe test I
Safety performance rating: ANSI/ISO C64444
Recommended working life: 10 years
Activity tolerance
Product code
18.5kBq (0.5mCi)
±20%
AMMK7649
29.6kBq (0.8mCi)
±20%
AMMK7650
Closure: 6-point stake or extended width crimp pattern
Quality control: Wipe test I
Safety performance rating: ANSI/ISO C64444
Recommended working life: 10 years
3
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Foil Pieces
Users of un-mounted foil pieces must have specialized radioactive
handling and testing facilities, which need to be licensed by an
appropriate national regulatory authority.
Measurement
To control the content of individual foil pieces, the radioactive
content of all rolled foil, and hence the final activity per unit area,
is accurately measured.
Five standard foil piece types are presently available. Nonstandard designs can be provided on request.
Activity
Activity
tolerance
Product
code
Size(mm)
18.5kBq (0.5mCi)
±20%
AMMK7169
f 2.38
29.6kBq (0.8mCi)
±20%
AMMK6045
f 2.38
18.5kBq (0.5mCi)
±20%
AMMK5588
f 5.00
29.6kBq (0.8mCi)
±20%
AMMK3457
f 5.00
18.5kBq (0.5mCi)
±20%
AMMK7620
3.5 x 3.5
Depending on user requirements and quantities involved, it is
possible to offer the following additional measurements:
·
activity content of individual sealed sources or foil pieces
·
spectrometry showing typical emitted energy distribution
·
full-width half-maximum values determined from
spectrometry, i.e. the energy width at half the maximum
intensity value
·
spatial distribution - the measured intensity along the 2p arc
above the emitting surfaces from a given batch.
·
ion current as measured in an ionization chamber with an
agreed specific geometry.
·
acceptable quality level (AQL)
Safety performance testing: ANSI/ISO C64444; IAEA Special
Form is applicable to foil pieces greater than 5mm diameter.
When used as part of single station smoke detectors, Detector
Technology sources are also fully compatible with the
requirements of:
·
·
·
Safety Performance
ISO 2919 classification
Underwriters Laboratories Standard UL 217(2)
European Norm EN 54(3)
UK National Radiological Protection Board (NRPB)
criteria of acceptability(4) upon which intended UK
legislation relating to smoke detectors is based
Source performance under working conditions is tested in
accordance with internationally defined (ISO) standards. Please
refer to the Detector Technology document 'Safety and
Packaging'(7) for details of the test data and system of
classification.
Quality Assurance
The ISO rating recommended for ionization chamber smoke
detector sources is C32222. By use of optimum design
parameters, the performance of Detector Technology's sources
significantly exceeds this in all cases, as indicated above.
ISO 9001 conformity
The design, manufacture and testing of Detector Technology
Americium-241 foils is managed within the scope of the Quality
Management System which is approved by Lloyds Register
Quality Assurance for compliance with BS EN ISO 9001:2000.(5)
Other tests
Many other tests designed to simulate severe industrial
environments have been performed on samples of alpha foil,
including exposure to sulphur dioxide gas, to salt spray and to
ozone. Details of such tests can be supplied on request.
Quality Control
Surface contamination
National radiation regulations(9), in common with other national
regulations, require that radioactive sources should not be
handled with bare fingers. They must be handled using forceps,
vacuum pick-up or protective gloves, taking care not to damage
the emitting face. For alpha foil sources these simple procedures
are generally adequate, though other mechanical systems may be
used if required.
Sources in Holders: Sources in holders are batch tested in
conformity with BS 5288(6). External surfaces, including the
alpha-emitting faces, are wiped with a swab of tissue or cotton
wool moistened with alcohol or water. Any activity removed is
measured by a liquid scintillation counting technique. The
acceptance criterion is <185Bq (<5nCi).
Considerable additional safety precautions are required for the
processing of un-mounted foil pieces. Users may contact
Detector Technology or the competent national authority for
advice on particular operations but it is recommended that such
operations be entrusted to Detector Technology which has
extensive experience of all aspects of foil handling.
Foil pieces:. The tests used to check for surface contamination
depend on the size, shape and quantity of the pieces. The tests
may vary to suit user requirements. Further details are available on
request.
4
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
References
External radiation attributable to the Am-241 source in an ICSD
is normally extremely low. The following approximate dose rate
calculations based on thermo luminescent dosimetry data derived
in respect of a typical Detector Technology ICSD are given for
guidance. These data will enable users to comply with the US
Code of Federal Regulations [10 CFR.32.26.(6).]
Directions
Distance
(cm)
Normal to surface
of outer cap electrode
5
Normal to surface
of outer cap electrode
25
Normal to source
electrode
5
Normal to source
electrode
25
1. 'Smoke Detector Ionization Chambers: DSCA2 and DSCA3.'
Data Sheet No 11247, Detector Technology, 1979.
2. 'Standard for Single and Multiple Station Smoke Detectors.'
UL 217, Fourth Edition, Underwrites Laboratories Inc.,
Northbrook, Illinois, 10th May 1993.
Dose rate
Sv/year
rem/year
0.1
0.01
0.005
0.0005
0.6
0.06
0.003
0.0003
3. 'Components of Automatic Fire Detection Systems.' EN 54,
European Commission for Standardization (CEN), Brussels,
July 1982.
4. 'Board Statement on Approval of Consumer Goods
Containing Radioactive Substances.' Documents of the NRPB,
Volume 3, No. 2, National Radiological Protection Board,
Didcot, 1992.
5. 'Quality systems: Model for quality assurance in design,
development, production, installation and servicing.' BS EN
ISO 9001, British Standards Institution, London, 1994.
By comparison, the background dose rate can typically be
2mSv/year (0.2rem/year) in the UK and 3.7mSv (0.37rem/year)
in the USA.
6. 'Specification - sealed radioactive sources.' BS 5288, British
Standards Institution, London 1976.
Reference may also be made to the Detector Technology ‘Safety
and Packaging' document(7). For any other safety advice please
enquire as above.
7. 'Safety and Packaging.' Data sheet reference HI045.
SOU/120/95/KI, Detector Technology, 1995.
Nuclear Data for Am-241
used in Detector Technology Foil
8. 'IAEA Safety Standards: Regulations for the Safe Transport of
Radioactive Materials, 1985 Edition. As Amended 1990.'
International Atomic Energy Authority, Vienna, 1990.
Half-life
9. 'The Ionising Radiations Regulations 1985.' Statutory
Instrument 1985 No. 1333: Health and Safety, Her Majesty's
Stationery Office, London, 1990.
433 years
Principal
alpha particle
energies
Principal
photon particle
energies
Radionuclidic
purity
5.338MeV 14%
59.5kV (36%)
<0.5% Am-241
5.445MeV 12.8%
Np LX-rays
<0.0001% other
5.486MeV 85.2
12-22keV (~40%)
gamma impurities
Others Low
Chemical purity > 99%
5
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Smoke detector ionization chambers
DSCA2C and DSCA3C
DSCA2C and DSCA3C
General description
Both the DSCA2C and DSCA3C products incorporate a dual
ionization chamber of advanced design containing a single
radioisotope source producing ionization in both chambers. The
design was developed using a computer model to optimize
performance characteristics. A performance test electrode is
incorporated in the DSCA3C.
The design, manufacture and testing of the DSCA2C and
DSCA3C ion chambers are managed within the scope of the
Detector Technology Quality System which is certified by Lloyds
Register Quality Assurance for compliance with BS EN ISO
9001:2000.(1)
Side View
The general construction was designed to meet the requirements
of Underwriters Laboratories Inc. Standard UL 217(2) and EN
54:part 7.(3) and both designs have been recognized by UL for
many years.
For maximum corrosion resistance the electrodes and source
holder are made of AISI 316 stainless steel, the support molding
of polypropylene and the insulators of polytetrafluoroethylene
Teflon™.
Details of the source are given in the data sheets 'Americium-241
alpha foil and sources'(4) and 'Safety and Packaging'(5), both
available on request. In accordance with OECD requirements(6)
the source activity is less than 37kBq (lmCi) Am-241. The
Recommended Working Life of the source is 10 years. The
ANSI/ISO classification of the ionization chamber is C64646.
View from underneath
The units as supplied are assembled ready to mount on a suitable
printed circuit board using the pre-tinned tags provided. No
source adjustment is required.
B
A
The DSCA3C's test electrode permits the checking not only of
the operational functioning of the ion chamber but of all
associated electronic circuitry. When actuated, the electrode
disturbs the balance conditions to simulate the presence of smoke
by an obscuration of 4.0%/Ft.
A. Outer Cap Electrode
B. Source Plate Electrode
C. Test Electrode
D. Collector Electrode
C
The design is compatible with commercially available integrated
circuits.
Detector Technology expertise in the design and construction of
ion chambers is long established and wide-ranging. A consultancy
service is available to assist in the design of systems using ion
chambers.
A
6
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Regulatory Compliance
To improve corrosion resistance, the associated circuitry should
be sealed in a container, using a suitable sealant where the
chamber terminals enter the chamber (avoiding sealant on the
collector electrode insulator).
Detector Technology sources used in the detectors meet the
regulatory requirements of most national authorities worldwide.
Chambers intended for use at high altitudes may require
adjustment of the tripping level of the detector circuit for
optimum sensitivity.
Specifically Detector Technology sources comply with:
·
·
·
European Norm EN 54(3)
UK National Radiological Protection Board (NRPB)
criteria of acceptability(7) upon which UK legislation
relating to smoke detectors is based.
Sources have been recognized by Underwriters
Laboratories Inc in compliance with Standard UL 217(2)
as a component of smoke alarms and detectors.
Within reasonable limits, the balance potential remains relatively
unaffected by temperature, pressure, humidity and wind velocity.
Specification
The general specification is tabulated below. Conditions, except
where specified, are:
Principle of Operation
·
·
·
The collector electrode is charged by an imbalance in the
ionization currents flowing in the inner and outer chambers, until
these currents come into balance. In the absence of smoke or
combustion products, the balance potential remains constant,
apart from small variations due to statistical fluctuation of the
ionization current.
Minimum
Collector electrode
balance potential
When smoke enters the chambers the ionization currents change,
that in the outer chamber more so than in the inner camber. The
collector electrode is then charged to a new balance potential.
The change in potential is used to trigger an alarm circuit.
·
Typical
Maximum
Units
5.0
-
6.0
V
at 0.2% obscuration foot *
at 0.4% obscuration foot *
-
0.7
0.3
-
V
V
Insulator leakage
-
-
0.5
pA
Capacitance (collector to
outer + source electrode)
-
6
-
pF
-
20
0.5
26
0.7
kBq
mCi
Change in collector balance
potential with smoke:
The performance of the DSCA3C has been independently
assessed in the following two studies:
·
Outer electrode to source electrode potential: 9V
Temperature: 20°C ± 3°C
Ambient pressure: atmospheric, near sea level, clean air
in smoldering smoke and fire tests by Underwriters
Laboratories Inc.(8)
in accordance with a 'Testing Program for Automatic
Fire Alarm Equipment for Residential Use' by the
Danish Research Centre for Applied Electronics(9)
Am-241 activity
* Obscuration limits specified by UL 217(2)
Copies of both reports are available on request.
Precautions and Recommendations
The ionization current is approximately 20pA. Precautions to
preserve the insulation of the input connection path to the
electronics are critical for correct operation of the device. In
particular the collector electrode and its connections must remain
free from contamination, e.g. from solder flux or manual contact.
The lead from the collector electrode to the detector circuit
should preferably be short and clear of the circuit board and
other components.
The chamber is shielded from external electric fields by its outer
cover. Suitable shielding should be provided for the associated
circuitry, because of the necessarily high impedance of the circuit
connected to the chamber collector electrode.
7
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Radiological data
Performance
Users of these units in all countries should ensure that they
comply with all relevant regulations on the control of radioactive
materials.
Collector potential
change with B.S. smoke
Whatman #2 filter paper
heated on electric element
The DSCA3C unit has been independently assessed and found
satisfactory in the following respects:
·
·
a general Radiological Assessment by the NRPB(10)
an NEA 1200°C incineration test by the NRPB(11)
Copies of the NRPB reports are available on request.
In both devices, external radiation attributable to the Am-241
sealed source is normally extremely low. The following
approximate dose rate calculations based on thermo luminescent
dosimetry data derived in respect of a typical Detector
Technology unit are given guidance. These data will enable users
to comply with the US Code of Federal Regulations [10
CFR.32.26(6).]
Directions
Distance
(cm)
Normal to surface
of outer cap electrode
5
Normal to surface
of outer cap electrode
25
Normal to source
electrode
5
Normal to source
electrode
25
% obscuration per Foot
Ratio of collector potential
at balance
to supply potential
Dose rate
Sv/year
rem/year
0.1
0.01
0.005
0.0005
0.6
0.06
0.003
0.0003
Supply (V)
Balance voltage change
with time after activation of
the test electrode
By comparison, the background dose rate can typically be
2mSv/year (0.2rem/year) in the UK, or 3.7mSv (0.37rem/year) in
the USA.
Reference may also be made to the Detector Technology 'Safety
and Packaging' document(5). For any other safety advice please
enquire as above.
Seconds
Collector potential change
With altitude
Pressure (mmHg)
Altitude (feet)
8
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Smoke detector
ionization chambers
DSCB1C & DSCB2C
Fig 1 -DSCB1C
General Description
The DSCB1C (fig 1) is a small, compact and robust dual
ionization chamber of advanced design containing a single
radioisotope source producing ionization in both chambers. The
chamber has a unique internal geometry, which allows the
detector chip to be positioned beneath the chamber within a
recess in the moulded plastic base. Pin-15 of the chip can be
connected directly to the collector electrode inside the protective
RF shield of the cover. This isolates the highly sensitive
connection between the collector electrode and pin-15 from other
parts of the detection circuitry and it provides a high degree of
immunity from external electrical interference.
Fig 2 - Side view
The external design features and dimensions of the DSCB1C are
shown in figures 2 and 3. The design was optimised for smoke
sensitivity with the assistance of proprietary computational
modelling software, developed by Detector Technology. Smoke
detection performance is optimised, whilst minimising sensitivity
to climatic variations and to design tolerances.
The electrodes and source holder are made of AISI 304 stainless
steel. The plastic insulator material is specially chosen for its
exceptional mechanical stability and resistance to moisture and
oxidising chemicals in the air. The units are supplied assembled
and ready to mount on a suitable printed circuit board using the
pre-tinned tags provided.
Dimensions in mm
Fig 3 - Bottom view
Details of the sealed source design can be found in the data
sheets 'Americium-241 alpha foil and sources' (4) and 'Safety and
Packaging'(5). Both of these are available on request. In
accordance with OECD requirements (6) the source activity is less
than 37kBq (1mCi) Am-241. The Recommended Working Life of
the source is 10 years. The BS/ISO/ANSI rating of the
ionisation chamber is C64646.
The design manufacture and testing of the DSCB1C is managed
within the scope of Detector Technology's Quality System which
is certified by Lloyds Register Quality Assurance for compliance
with BS EN ISO9001:2000 (1)
Detector Technology expertise in the design and construction of
ion chambers is well established and wide-ranging. A consultancy
service is available to assist in the design of systems using ion
chambers and in the provision of testing and computational
modelling services to measure and model the performance of
customers' own designs.
Dimensions in mm
1
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Fig 4, DSCB1C – internal design schematic
Fig 6a DSCB1C smouldering paper sensitivity
computer modelled ion distribution
C han ge in Balance voltage vs Light O b scuratio n
S moulder ing Paper Te st
2.5
2
dV (volts)
source
chip recess
1.5
1
0.5
0
0
source electrode
cover electrode
Fig 5
1
2
3
4
Light O b scuratio n %
collector
electrode
Fig 6b DSCB1C sensitivity smoky paraffin
Recommended circuit design for use with
the MC1446 detector chip
C hange in B alanc e voltag e vs Lig ht Ob scurati on
S m o ky P araffin Test
3
dV (volts)
2
1
0
0
1
2
3
Lig ht Ob scura tion %
Fig 6c DSCB1C smouldering wick sensitivity
Cha ng e in Ba la nce vo lta ge vs L ig ht Ob scu ration
Smou ld erin g Wick T e st
Performance and Sensitivity
4
The smoke detection performance of the DSCB1C chamber has
been measured using a variety of different types of smoke.
Sensitivity to smouldering paper, smoky paraffin and smouldering
wick are shown in figures 6a, 6b and 6c.
dV (volts)
3
2
1
Performance and sensitivity to humidity, temperature, pressure
and air velocity are shown in figures 7, 8, 9 and 10. The air
velocity response may vary depending on the design and
configuration of components adjacent the ion chamber in the
smoke alarm.
0
0
1
2
3
4
Lig ht Obscu ration %
Fig 7 DSCB1C humidity response at 230C
DSCB2C Ion Chamber
7
Balance Voltage (V)
The DSCB2C is a modified version of the DSCB1C in which the
bent-in louvers in the cover shown in fig.1 have been removed. It
provides the DSCB2C with the benefit of having a fast response
to smouldering fires by allowing air to flow more easily through
the chamber. This design also limits the stability of the unit when
operating under conditions of high air velocity. Customers may
select either the DSCB1C or DSCB2C designs to optimise
whichever performance characteristics are preferred.
6
5
4
3
2
1
0
0
2
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
20
40
60
% Relative Humidity
80
100
Fig 8 DSCB1C Temperature response at 60%RH
Precautions and Recommendations
The ionisation current is approximately 16pA. Precautions to
preserve the insulation of the input connection path to the
electronics are critical for correct operation of the device. In
particular the collector electrode and its connections must remain
free from contamination e.g. from solder flux or manual contact.
The lead from the collector electrode to the detector circuit
should preferably be short and clear of the circuit board and
other components. Direct connection between pin-15 of the
detector chip and the collector electrode within the recess of the
chamber is highly recommended.
Balance Voltage (V)
7
6
5
4
3
2
1
0
The chamber is shielded from external electric fields by its outer
cover. Suitable shielding should be provided for the associated
circuitry, because of the necessarily high impedance of the circuit
connected to the chamber collector electrode.
0
Within reasonable limits, the collector electrode potential remains
relatively unaffected by temperature, pressure, humidity and wind
velocity as shown in fig, 8, 9 and 10. Chambers intended for use
at high altitudes may require adjustment of the tripping level of
the detector circuit for optimum sensitivity.
20
40
Temperature (C)
60
Fig 9 DSCB1C Air pressure Response
Balance Voltage (V)
7
Specification
The general specification and operating performance under
ambient environmental conditions are as follows:
- Temperature 200C ±30C
- Ambient pressure: atmospheric, near sea level, clean air
- Outer electrode to source electrode potential: 9V
- The CEV is nominally 5.6V ±0.4V.
- Change in CEV with smoke
1% obscuration /foot* 0.6V typical
4% obscuration / foot* 2.2V typical
- Insulation leakage <0.5pA.
- Capacity (collector to outer + source electrode) 6pF
- Am-241 activity 30kBq (~0.8mCi) ±15%
* obscuration limits specified by UL217 (2)
6
5
4
3
2
1
0
0.8
1
1.2
Air Pressure (bar)
1.4
.
Fig 10 DSCB1C Air Velocity Response
Regulatory Compliance
Detector Technology sources used in the detectors meet the
regulatory requirements of most national authorities worldwide.
Specifically Detector Technology sources comply with:
·
European Norm EN 54(3)
·
UK National Radiological Protection Board (NRPB)
criteria of acceptability(7) upon which UK legislation
relating to smoke detectors is based.
·
Sources have been recognized by Underwriters
Laboratories Inc in compliance with Standard UL 217(2)
as a component of smoke alarms and detectors.
Balance Voltage (V)
7
6
5
4
3
2
1
0
0
3
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
2
4
6
Air Velocity (m/s)
8
10
Technical Support and Design Services
References
Design and development services can be provided to assist
customers in the development of new and improved products.
1.
'Quality systems: Model for quality assurance in design,
development, production, installation and servicing.' BS EN
ISO 9001, British Standards Institution, London, 2000.
2.
'Standard for Single and Multiple Station Smoke Detectors.'
UL217, Fourth Edition, Underwriters Laboratories Inc.,
Northbrook, Illinois, 10th May 1993.
3.
'Components of automatic fire detection systems.' EN 54:
Part 7, European Commission for Standardization (CEN),
Brussels, July 1982.
4.
'Americium-241 alpha foil and sources.' Data Sheet No.
11262, Detector Technology, 1997.
5.
'Safety and Packaging.' Data sheet reference
SOU/120/95/KL, Detector Technology, 1995.
6.
'Recommendations for ionization chamber smoke detectors
in implementation of radiation protection standards':
Section 6 Nuclear Energy Agency, Organisation for
Economic Co-operation and Development, Paris, 1977.
7.
'Board Statement on Approval of Consumer Goods
Containing Radioactive Substances.' Documents of the
NRPB, Volume 3, No. 2, National Radiological Protection
Board, Didcot, 1992.
8.
'Smoldering Smoke And Fire Tests for Model DCS.A3.'
S2182 78NK7050, Underwriters Laboratories Inc.,
Northbrook, Illinois, 22nd August 1978.
Further information about computational modelling, design and
development services offered by Detector Technology can be
provided on request.
9.
'Informative Test of AFAR-Equipment.' Report No.
324323, Elektronikcentralen: Danish Research Centre for
Applied Electronics, Copenhagen, 10th April 1979.
.
10. 'Measurement Report: Radiological Assessment.' EMR/1
34/79, National Radiological Protection Board, Didcot,
1979.
Detector Technology has developed advanced computational
modelling software, which is capable of modelling the
performance of ion chambers as a function of design geometry.
An example is a compact design that had been modelled prior to
prototyping. The performance predicted by the model was later
verified in prototype tests to be similar to the performance of
larger standard designs.
Fig 11 – Example: compact ion chamber prototype
~1cm
height
.
~2cm diameter
11. 11.'Analytical Report: NEA 1200°C incineration test.'
NRPB/CP 3/016, National Radiological Protection Board,
Leeds, 1985.
4
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Quality control contents
Routine production checks
Special safety performance test on
prototypes
Measurements
Test reports
ISO.9001 International quality management
system standard
5
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108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Quality control
Quality control of radiation can be divided into four main parts:
1. Routine production checks
Quality Assurance
Radiation sources are manufactured in accordance with a strict
quality assurance program, details of which can be obtained on
request.
Leakage and contamination tests
Stringent tests for leakage are an essential feature of radioactive
sources production. They are based on ISO 9978. Some standard
methods used for testing radiation sources are listed below.
Wipe test I
The source is wiped with a swab or tissue, moistened with ethanol
or water, the activity removed is measured.
Limit: 200Bq
(Limit USA: 5nCi)
Immersion test II
The source is immersed in a suitable liquid at 50°C for at least 4
hours and the activity removed is measured.
Limit: 200Bq
(Limit USA: 5nCi)
Bubble test III
The source is immersed in water or a suitable liquid and the
pressure in the vessel reduced to 13kPa (100mm Hg). No bubbles
must be observed.
Krypton emanation test V
The source is held under reduced pressure for 24 hours. The
content of the chamber is analysed for Krypton-85 by
scintillation counting.
Limit: 370Bq
Krypton emanation test VI
The source is held under reduced pressure for 24 hours. The
content of the chamber is analysed for Krypton-85 by
scintillation counting. The test is repeated after at least 7 days.
Limit: 1.85kBq
6
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Quality control
4. Test reports
2. Special safety performance tests on
prototypes
A test report is supplied with each source or batch of sources.
Where appropriate the following information is given:
Product code
Product description
Capsule type
ISO classification
Special form certificate
Serial number of source
Measurement check
Leakage check
Contamination check
A radiation source must provide highest possible integrity
together with minimum attenuation of the required radiation by
the encapsulation materials. A compromise must sometimes be
made, particularly for alpha, beta and low energy photon sources.
Safety must always be the prime consideration. Standards for the
testing of sealed radioactive sources have been specified by
ISO.2919 and ISO.9978.
ISO.2919 'Sealed radioactive sources — Classification'
ISO.9978 'Sealed radioactive sources — leak test methods'.
ISO.9001 International Quality
Management System Standard
This classification system is modeled on USA standard US ANSI
N43.6-1997 which also gives a number of comparable leak test
methods.
In addition to our routine quality control procedures,
Detector Technology is approved to the International Quality
Management System Standard ISO 9001: 2000.
3. Measurements
This Quality Management System is a formal system which
defines Quality Policy, describes the necessary organization in
place to carry out the policy, and describes the procedures in
place which are necessary to carry out and maintain the system.
Each source of batch of sources is checked to ensure that the
strengths of the sources supplied are within the limits specified.
Wherever possible the results of these checks are indicated on the
test report. The methods of specifying the strengths of sources
are discussed under the heading specification on page E1 and
details are included in the appropriate section of this catalog.
The System involves the thorough training of all staff,
documentation of procedures, maintenance of records and the
assessment and rectification of non-conformities.
Regular surveillance audits are made by Lloyd's Register Quality
Assurance Ltd..*, to ensure that the high standards demanded by
ISO.9001 are maintained by Detector Technology to all stages of
the source production process from establishing the source
specifications, through design, manufacture, test and
measurement to dispatch and after sales service.
* Lloyd's Register Quality Assurance Ltd. (LRQA) is accredited by
the National Accreditation Council for Certification Bodies.
7
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Technical information contents
Specifications – SI Units
Technical information
8
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Technical information
Specification - SI Units
The International System (SI) units are a consistent set
of units for use in all branches of science. The International
Commission on Radiation Units and Measurements (ICRU)
has published its recommendations on the quantities and units
to be used in the measurement of ionizing radiations and
activity.
Several countries have already adopted the new SI system and
legislation now requires that SI units be used in the UK and
Europe from 1st January 1986 onwards. Previously, our catalogs
have contained both the old and the new units side by side, or
appropriate conversion factors, and this will continue until the
new system is accepted by the majority of users.
The quantity exposure rate is replaced by the quantity air kerma
rate. The preferred SI units for air kerma rate are submultiples of
Gray per second. A constant factor may be used to convert from
exposure rate to air kerma rate. Quite simply, an exposure of 1
Roentgen per hour (1R/h becomes 2.425 microGray per second
(mGy/s), or 8.73 milligray per hour (mGy/h). Gamma radiation
sources are specified in terms of the exposure rate or air kerma
rate at a distance of 1 meter from the source and at this distance
the strength of most sources is such that exposure rate will be in
units of mR/h and air kerma rate will be in units of (mGy/h. A
conversion factor of 8.73 should therefore be used to convert
from mR/h to mGy/h
Sources previously specified in terms of equivalent activity may
be converted to the new quantity and units by first converting to
exposure rate using the appropriate exposure rate constant. A list
of exposure rate constants used by Detector Technology for
these sources is given in the examples. Conversion from exposure
rate to air kerma rate is described in the previous paragraph and is
also shown in the examples.
In this catalog, source strengths are quoted in appropriate SI units
with the previously used quantities and units given alongside.
The following quick reference guide gives a useful summary of
the relevant quantities, units, conversion factors and prefixes.
Some useful examples are given.
9
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Technical information
Prefixes for units
Quick reference guide to the use of SI
units for gamma radiation sources
Sub multiples
10-3
10-6
10-9
10-12
10-15
10-18
Specification of output
New quantity: Air kerma rate
Old quantity: Exposure rate or equivalent activity + exposure
rate constant
New unit: Gray (Gy) per second (s)
Old unit: Roentgen (R) per hour (h)
Conversion of activity
Multiply value by 8.73 to convert from mR/hour to mGy/h
Multiples
milli
micro
nano
pico
femto
atto
m
m
n
p
f
a
103
106
109
1012
1015
1018
kilo
mega
giga
tera
peta
exa
k
M
G
T
P
E
Examples
Specification of activity
Quantity: Activity (content)
New unit: Becquerel (Bq)
Old unit: Curie (Ci)
Example of the conversion of outputs for an
equivalent activity of 1 Curie
Nuclide
Exposure rate at 1m*
Air kerma rate at 1m
Activity conversion
Multiply value by 37 to convert from kCi to TBq or Ci to GBq or
mCi to MBq
Multiply value by 27.03 to convert from MBq to mCi or GBq to
mCi or TBq to Ci
Cs-137
Co-60
0.33R/h
1.30R/h
2.9mGy/h
11mGy/h
* The value given are also the recommended exposure rate
constant values in units of R m2 h-1 Ci-1
Radiation Protection
Quantity: Absorbed dose
New unit: Gray (Gy)
Old unit: rad
Quantity: Dose equivalent (biological dose)
New unit: Sievert (Sv)
Old unit: rem
Examples of conversion for units of content activity
1 Bq = 2.703 x 10-11 Ci = 27.03pCi
1nCi = 3.7 x 10Bq = 37Bq
1 kBq = 2.703 x 10-8 Ci = 27.03nCi
1mCi = 3.7 x 104Bq = 37kBq
-5
1 MBq = 2.703 x 10 Ci = 27.03mCi
1mCi = 3.7 x 107Bq = 37MBq
1 GBq = 2.703 x 10-2 Ci = 27.03mCi
1Ci = 3.7 x 1010Bq = 37GBq
1 TBq = 2.703 x 10 Ci = 27.03 Ci
1kCi = 3.7 x 1013Bq = 37TBq
Conversion
Multiply value by 10 to convert from rad to mGy or rem to mSv
Multiply value by 100 to convert from Gy to rad or Sv to rem
10
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Technical information
Calibration
Notes
Some of the sources listed in this catalog can be calibrated.
Certificates of measurement quote the results of air kerma rate at
a specified distance.
Daughter Nuclides
Some daughter nuclides may not be in equilibrium with the parent
nuclide when source is supplied. In cases where this may occur
the transition probabilities for the daughter nuclides relate to
disintegrations of each daughter; this is stated in the tables.
Daughter nuclides with half-lives greater than the parent nuclide
have not been listed since they would be present only in
insignificant amounts.
Calibration uncertainty
The reported uncertainty is based on standard uncertainty
multiplied by a coverage factor k = 2, providing a level of
confidence of approximately 95%. (ISO Guide, 1995).
Particular energies
For ß-emission, the end-point energy is quoted.
Transition probabilities
These are expressed as percentages of the total number of
nuclear transformations of the relevant nuclides. For
electromagnetic transitions the probability of photo emission has
been listed.
Abbreviations
Half-lives
y - years
d - days
h - hours
min - minutes
s - seconds
ms - milliseconds
ms - microseconds
Type of decay
e.c. - electron capture
i.t. - isomeric transition
s.f. - spontaneous fission
Photons emitted
IC - indicates that photons of the stated energy are ~ 100%
internally converted.
11
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Source safety contents
ANSI / ISO classification
Performance requirements
IAEA special form
Source working life
12
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
Hong Kong: Detector Technology Limited, Suites 1401-02, 14/F., Dah Sing Financial Centre
108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Source safety
The suitability and safety of a source will depend on the intended
application and the environment of use of which there will be a
wide range. It is the customer's (users) responsibility to ensure the
source and its specification is suitable and safe for his particular
application and environment of use. This applies to standard
products and especially to non-standard products or custom
made designs. The information given here is intended for
guidance. It is recommended that the standards should be
consulted for detailed definitive information.
The standard tests for the classification of sealed source
performance (ISO 2919) are given in Table 1. Examples of
additional tests which may be required for specific applications
are given in the appendix to ISO 2919.
1. Classification of sealed source
performance
A radiation source must provide the highest possible integrity for
its contents together with the minimum attenuation of the
emitted radiation by the encapsulation materials which is
consistent with safety and the intended use. However, safety must
always be the prime consideration.
The International Organization for Standardization have issued a
standard (ISO 2919:1999) which establishes a system of
classification of sealed radioactive sources based on test
performance. It also specifies production tests, marking and gives
an example of a test report. Similar standards are ANSI/HPS
N43.6-1997 published in the USA.
These standards, to quote from ISO2919, "...provides a set of
tests by which the manufacturer of sealed radioactive sources can
evaluate the safety of his products in use and by which the user
of such sources can select types which are suitable for the
required application, especially where the release of radioactive
material with consequent exposure to ionizing radiation is
concerned."
13
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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108, Gloucester Road, Wanchai, Hong Kong, Phone No: + 852 2596-7711
Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Source safety
Table 1. Classification of sealed source performance
Test
Class
1
Temperature No test
2
-40°C (20min)
+80°C (1 h)
3
4
-40°C (20min) +
180°C (1h)
-40°C (20min) +
400°C (1 h) and
thermal shock to
20°C
5
-40°C (20min)
+600°C (1h) and
thermal shock to
20°C
6
X
-40°C (20min)
Special test
+800°C (1 h) and
thermal shock to
20°C
External
pressure
No test
25kPa absolute to 25kPa absolute to 25kPa absolute to 25kPa absolute to 25kPa absolute to Special test
atmospheric
2MPa absolute
7MPa absolute
70MPa absolute
170MPa absolute
Impact
No test
50g from 1 m or
equivalent
imparted energy
Vibration
No test
3 times 10min 25 3 times 10min 25
to 500Hz at
to 50Hz at
49m/s2 (5gn)1)
49m/s2 (5gn)1)
and 50 to 90Hz
at 0.635mm
amplitude peak
to peak and
90 to 500Hz at
96m/s2 (5gn)1)
3 times 30min
Not used
25 to 80Hz at
1.5mm amplitude
peak to peak and
80 to 2000Hz at
196m/s2 20gn)1)
Puncture
No test
1 g from 1 m or
equivalent
imparted energy
50g from 1 m or
equivalent
imparted energy
200g from 1 m or 2kg from 1 m or
equivalent
equivalent
imparted energy imparted energy
10g from 1m or
equivalent
imparted energy
5 kg from 1 m or
equivalent
imparted energy
20kg from 1 m or Special test
equivalent
imparted energy
Not used
300g from 1 m or 1 kg from 1 m or
equivalent
equivalent
imparted energy imparted energy
Special test
Special test
1) Acceleration maximum amplitude
Each test can be applied in several degrees of severity which is
expressed as a five digit code representing the class numbers
which describe the performance for each of the tests. The digits
are preceded by the letter C or E indication respectively whether
the activity of the source is greater or lesser than a prescribed
amount. The limits depend on the toxicity etc of the active
components (See ISO 2919) Compliance with the tests is
determined by the ability of sealed source to maintain its leak
tightness. The leakage tests are defined in ISO 9978.
Notes to table 1.
1. Details of the testing procedures are given in ISO.2919 and
ANSI N43.6-1997. A further class X can be used where a
special test procedure has been adopted.
2. External pressure
100kPa=1 atmosphere (approximate)
3. Impact test
The source, positioned on a steel anvil, is struck by a steel
hammer of the required weight; the hammer has a flat stricking
surface, 25mm diameter, with the edges rounded.
4. Puncture test
The source, positioned on a hardened steel anvil, is struck by a
hardened pin, 6mm long, 3mm diameter, with hemispherical
end, fixed to a hammer of the required weight.
14
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Source safety
2.- Performance requirements for typical uses
Typical uses and minimum performance requirements (ISO 2919) are given in Table 2.
Table 2 Sealed source classification (performance) requirements for typical usage
Sealed source class, depending on test
Temperature
Pressure
Impact
Vibration
Puncture
Radiography-Industrial
Sealed source
Source to be used in device
4
4
3
3
5
5
1
1
1
1
Medical
Radiography
Gamma teletherapy
Brachytherapy (6)1)
Surface applicators2)
3
5
5
4
2
3
3
3
3
5
2
3
1
2
1
1
2
4
1
2
4
4
3
3
3
2
3
3
3
2
Beta gauges and sources for low-energy gamma gauges or x-ray
fluorescence analysis2)
3
3
2
2
2
Oil-well logging
5
6
5
2
2
Portable moisture and density gauge
(including hand-held or dolly-transported)
4
3
3
3
3
General neutron source application (excluding reactor startup)
4
3
3
2
3
Calibration source activity >1 MBq
2
2
2
1
2
4
5
3
3
3
4
2
2
3
4
3
2
3
2
2
2
2
2
2
1
2
2
1
2
2
Gamma gauges
(medium and high energy)
Gamma irradiation sources
Ion generators3)
Unprotected source
Source in device
Category 1 2) [3], [5]
Categories II,III and IV 3)
Chromatography
Static eliminators
Smoke detectors2)
1) Sources of this nature may be subject to severe deformation in use. Manufactures and users may wish to formulate additional or special test procedures.
2) Excluding gas-filled sources.
3) "Source in device" or a "source assembly" may be tested.
The requirements take into account normal usage but do not include exposure to fire, explosion or corrosion. The tests specified do not cover
all usage situations and where conditions do not match those specified in Table 2 appropriate tests on an individual basis may be required.
15
USA: QSA Global Inc. 40 North Avenue, Burlington MA 01803 - Phone No: +1 781 272-2000
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Germany: Nuclitec GmbH, Gieselweg 1, 38110 Braunschweig - Phone No: +49 (0)5307 9320
Current
(10-11 Amps)
Source safety
RECOMMENDED WORKING LIFE OF
SEALED RADIATION SOURCES
3. IAEA special form
The Recommended Working Life (RWL) is the maximum period
within which Detector Technology expects the source to meet
it's design requirements under proper conditions of environment
and usage. A Source should be replaced within the Recommended
Working Life or a proper assessment should be made to verify its
suitability for continued use.
Sealed sources which have passed the performance tests
described in the regulations for the Safe Transport of Radioactive
Material, 1996 Edition (Revised), International Atomic Energy
Agency (IAEA), No. TS-R-1 (ST-1, Revised) may be approved as
Special Form Material by a National Competent Authority.
Designation as Special Form allows an increase in the activity
limits for shipment as a Type A package.
Detector Technology makes no warranties, expressed or implied,
or guarantees as to how long any source can actually be safely
used. Adverse environments, conditions, improper usage or
materials combination in usage could effect the appearance and
integrity of the source and it is the user's responsibility to carry
out routine inspection and testing to determine when it should be
replaced.
This catalogue indicates whether Special Form Certificate (SFC)
were issued for approved items in the catalog.
Detector Technology will determine the RWL based on the
construction of the source, application, test data and operational
experience.
Issued by the Detector Technology Board June 2003
16
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