LA-UR-12-24629
Stationary Contamination Monitors
James T. (Tom) Voss
Los Alamos National Laboratory
Health Physics Measurements Group (RP-2)
Radiation Instrumentation and Calibration Team
LANL currently uses more than 400 Hand and Foot
Monitors (HFMs) in 5 different configurations.
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32 Eberline HFM-7s,
89 HFM-8s,
180 TA-55HFs (alpha only),
30 TA-HFs (beta pancake),
80 Ludlum Model 214s used as HFMs.
Eberline HFM-7s are alpha + beta HFMs
TA-HFs with the beta pancake are used as beta
hand monitors
• More than 300 of the HFMs are alpha-only using airproportional alpha detectors, this includes the HFM8s, TA-55 HFs (alpha only), and Ludlum Model 214s.
Approximately 1,000 Ludlum Model 214s and Model
215s are used as glove box monitors (GBMs).
The available HFM technologies are;
• P-10 gas-flow proportional,
• dual alpha + beta scintillator,
• GM pancake and sealed gas proportional (beta only),
• and air-proportional (alpha only).
• ZnS alpha + beta has been applied to hand-held
detectors but has not yet been available in HFMs.
This comparison covers the P-10 gas-flow proportional,
dual scintillator, and air-proportional alpha HFMs.
The HFMs in this comparsion are;
• Berthold LB146-2,
• Bladwerx cHFM,
• Canberra Sirius-5AB,
• Thermo HFM11,
• Fuji NHP,
• and Ludlum 4906.
• The LB146-2, cHFM, Sirius-5AB, and HFM11 are P-10
gas-flow proportional, the Fuji NHP is a dual
scintillator, and the 4906 is an air-proportional.
The PCMs (Personnel Contamination Monitors) in this
comparison are;
• Canberra Argos 5AB
• and Thermo Scientific iPCM12.
The evaluation criteria include;
• overall size,
• weight, durability,
• ease of use,
• detection capability,
• alarm capability,
• ease of maintenance and calibration,
• response to environmental affects,
• and response to interfering radiations.
Berthold LB 146-2
Foot print is approximately
31 by 34 inches
Weight is approximately
180 pounds
Bladewerx - cHFM
Compact Hand and Foot Monitor
Foot print is approximately
18 x 17.6 inches
Weight is approximately
75 lbs (34 kg)
Uses 2.5 sq. feet of floor space
Canberra Sirius-5AB
Foot print is approximately
30 by 37 inches.
Weight is approximately
290 pounds.
Thermo HFM11
Foot print is approximately
32 by 37 inches.
Weight is approximately
270 pounds.
Fuji NHP
Foot print is approximately
29 by 30 inches.
Weight is approximately
220 pounds.
Ludlum 4906
Foot print is approximately
36 by 31 inches
Weight is approximately
150 pounds
Canberra - Argos 5AB
Personnel Contamination
Monitor
Footprint is approximately
36 x 40.2 inches.
Weight is approximately
321 kg (706 pounds).
Thermo Fisher Scientific iPCM12 Installed Personnel
Contamination Monitor
Footprint is approximately
28.6 x 37 inches.
Weight is approximately
400 kg (880 pounds).
THE EVALUATION
OVERALL SIZE
The LANL HFM requirement of no more than a 36
by 36 inch footprint was met by 4 of the 6 HFMs
evaluated. Two of the HFMs that did not meet the size
requirement because one measurement was 37 inches.
WEIGHT
ALL of the HFMs met the LANL requirement of no
more than 300 pounds. Both PCMs were much heavier
than the HFMs but there was no limit on the weight of
PCMs.
DURABILITY
NONE of the HFMs fully met the LANL
requirement of durability. ALL of the HFMs and PCMs
have vulnerable detector windows.
EASE OF USE
NONE of the HFMs fully met the LANL
requirement of ease of use. Most of the problems
regarding ease of use are related to the positioning of
the hands of the user.
DETECTION CAPABILITY
ALL of the HFMs meet the LANL requirement of
detecting 500 DPM Alpha and 5,000 DPM Beta within
16 seconds. The alpha detection efficiencies of the
HFMs were from 10 to 14% and the beta detection
efficiencies were from 19 to 24%. The alpha
background count rates in the low background area
were from 1 to 18 CPM and the beta background count
rates were from 1,000 to 2,400 CPM. Note that the
Ludlum 4906 is an alpha-only HFM and obviously does
not detect beta radiations.
ALARM CAPABILITY
NONE of the HFMs fully met the LANL
requirement of alarm annunciation. Problems were
noted for both sound level on some of the HFMs and
the lack of sound indication on some of the HFMs.
EASE OF MAINTENANCE AND CALIBRATION
NONE of the HFMs fully met the LANL
requirements for ease of maintenance and calibration.
Problems were noted with the awkwardness of using
the calibration software and with replacing the hand
detectors.
RESPONSE TO ENVIRONMENTAL AFFECTS
The HFMs’ response to environmental affects
was not directly evaluated. According to the
manufacturers’ literature ALL of the HFMs will operate
with temperatures from 0 to 40 C and RH from 0 to
95%. With the small amount of radon data collected it
appears that ALL of the HFMs would meet the LANL
requirement of being able to operate with radon/thoron
concentrations up to 0.1 pCi/L.
RESPONSE TO INTERFERING RADIATIONS
ONLY the Ludlum 4906 can detect 500 DPM alpha in a
combined 5 mR/hr gamma field and 2 mRem/hr fast
neutron field. NONE of the other HFMs or PCMs can
detect 500 DPM alpha and 5,000 DPM beta in a
combined 5 mR/hr gamma field and 2 mRem/hr fast
neutron field.
The Berthold LB146-2, Bladewerx cHFM, Canberra
Sirius-5AB, Thermo HFM11, and Fuji NHP have a
calculated beta detection capability of approximately
14,000 DPM in a 1 mR/hr gamma field referenced to
Cs-137.
The response to interfering neutron radiation for these
HFMs has not been adequately measured.
ADDITIONAL CONSIDERATIONS
Berthold LB146-2
The LB146 is a production HFM, made in Germany.
Bladewerx cHFM
The cHFM is a production HFM, made in NM.
Canberra Sirius-5AB
The Sirius-5AB is a new product for Canberra. The
position of the hand detectors is somewhat awkward.
Thermo HFM11
The HFM11 is a production HFM, made in Germany.
The HFM11 calibration software is awkward to use.
Fuji NHP
The NHP is a production HFM, made in Japan,
but Apantec promises to manufacture parts in the US.
The NHP has been used successfully in Japan’s
nuclear power industry but may not fare well in some
LANL environments such as TA-54. The NHP is a dual
scintillator so it does not use P-10 gas. The NHP mylar
windows may be susceptible to being punctured. Fuji
gangs the front and back of the hand into one PMT,
which doubles the effective background for the hand
detectors. The hand detectors (front and back of the
hands) are parallel plates and the users fingertips are
too far from the detector for good alpha detection. Fuji
has promised to look into the detector spacing and the
vulnerability of the mylar windows.
Ludlum 4906
The 4906 is a new product for Ludlum. The large
area air-proportional alpha detectors may make it
more susceptible to radon/thoron interference.
(There is some evidence from our evaluation of the
Ludlum 215 that tends to support this supposition.)
Berthold Technology - LB 146-2 Hand and Foot Monitor
Hand Detectors:
15 x 23 cm
23.2% Am241;
38.5% Cl36
Foot Detectors:
15 x 35 cm
13.9% Am241:25.0% Cl36
Physical
Weight: 81 kg (178 pounds)
Dimensions: 70 x 87.4 x151cm
Footprint: 6.6 sq. ft.
7 detectors (feet & palm and back of hands plus a frisker)
Internal memory for 1,000 measured values. Each
value contains; date and time, values exceeding
thresholds, selected nuclides, personnel ID number if
enabled, activity levels at all measuring points.
The monitor performs the following diagnostic tasks;
monitoring for probe failure, background drift, gas
control, positional monitoring, external alarm signal,
error and status messages. Rapid recovery from
background changes with a dynamic background
counting time
USB and Ethernet connectivity
RadNet compliant (uses Berthold protocol)
Bladewerx - cHFM Compact Hand and Foot Monitor
Hand and Foot Detectors: Gas flow proportional, surface
area 135 in2 (871 cm2)
9”w x 15”d hand and foot detector (26.86 x 38.1 cm)
Frisker Detector:
100 cm2 active area
Beta Data Analysis
Dual threshold (beta with alpha cutoff) gross counting board
Background subtraction
Typical 15% efficiency for Cl-36
Alpha Data Analysis
Dual threshold (alpha with radon cutoff) gross counting board
Background subtraction
Typical 15% efficiency for Pu-239
Physical
AC/DC power, operates for 4 hours on battery back up
Weight: 75 lbs (34 kg)
Dimensions: (W x D x H) 18” x 17.6” x adjustable
2.5 sq. feet of floor space
3 detectors including frisker
2 step monitoring
Alarms may be set on individual detectors
USB and Ethernet connectivity
RadNet compliant
Thermo Scientific - iPCM12 Installed Personnel
Contamination Monitor
Dimensions
0.725 x 0.94 x 2.22 meters (2.38 x
3.08 x 7.28 feet)
Footprint
7.33 sq. ft.
Weight
400 kg (880 pounds)
• Alpha & beta detection geometry, building on the PCM2
design.
• Coverage area greater than PCM2 with almost 17,000
cm2 detection area.
• Utilizes 21 detectors in monitoring the body, hands and
feet
• Detectors are split into four detection zones
• Sum zones may be applied across all detectors
• All background, measurement, source checking, event
log, voltage scanning is stored to an SQL database within
the monitor, providing both local and remote access
• Alarms may be set on single detectors or sum zones
• Each measurement result may be stored against a
personnel identifier
• Rapid recovery from background changes with a dynamic
background counting time
• USB security dongle — allows supervisors access to
diagnostic modes to further investigate the results;
features three security levels
• QuickScan algorithm — allows for faster beta and
gamma contamination monitoring without compromising
the statistical probabilities of detection or false alarm
• Changing background indication signal — highlights
significant changes in background radiation
• Changing conditions alarm — indicates if there is a
significant change in the count rate during the
monitoring period, invalidating the measurement
• Calibration Integrity checking
• Windows XP operating system and Series 12 Software
based upon that in SAM12 and PM12
• USB and Ethernet connectivity
• RadNet compliant
Detector Efficiency
Body, hand, leg, arm, top of toe
Cl36
Am241
24 ± 3 %
14 ± 3 %
Foot
15 ± 3 %
9±3%
Questions ? ?
Tom Voss
505-667-8930
tvoss@lanl.gov
WWW.HPICORG.COM