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| AM1F Continuous Air Monitor Fixed Filter |
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GAIN STABILIZED |
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| AM1F Continuous Air Monitor Fixed Filter |
| The AM1F is a low profile fixed filter monitor designed to continuously collect and measure the quantity of
radioactive beta particulates or gamma iodines in the sample stream. The system will monitor radioactive airborne levels in either working spaces, or via a
process tubing connection to a remote stack, duct or other air space. The AM1F can be set for representative sampling if desired. |
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System Design Information |
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The sampler uses a fixed filter geometry with three
inches of lead shielding. Internal to the sampler is an
Apantec SD201P beta scintillation detector for sensitivity
to beta particles or SD200N gamma scintillation detector
for measurement of iodines. The sampler accepts both a
particulate filter paper and an optional activated charcoal
cartridge using a common filter holder mechanism. The
detector is positioned in a lead shield, Model AS43F in
close proximity to the sample deposition point. |
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The detector has an associated Preamp/SCA model
SDA3E for operation of the detector, and for pulse
analysis. The output of the SDA3E is wired to a locally
mounted RM1W display and control unit. The SDA3E
Preamplifier includes three separate single channel
analyzer circuits which are set to window the beta,
activities. A vacuum pumping system capable of 1
SCFM (30 LPM) is included on the AM1F monitoring
skid. The pumping system will include local mass flow
control of the process fluid to maintain sampling rates
during filter loading. Pump controls will be provided on
the local skid. The local RM1W units interface with an
optional remote RM1R unit or DORIS software via serial
communications for full remote control of each channel.
When used for isokinetic sampling, the flow rate on the
sample skid is controlled using a velocity signal from the
sample point to minimize sample loss during
transmission of the sample to the filter deposition point. |
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| SYSTEM FEATURES |
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System Skid Assembly, fully wired & plumbed
AS43F Lead Shielded Sampler
SD201P Beta Scintillation Detector or SD220N
Gamma Scintillation Detector
Isotopic Check Source (optional)
Fixed Filter Holder
Preamplifiers/SCA/HV Supply
RM1W Display and Control Units
Pump and Sample Control (purge) Modules
Power Distribution Box
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| SD201P/SDA3E Scintillation
Detector/Preamp |
Apantec has developed the SD Series of detectors for
use in process monitoring systems. For the AM1FP
channel, Apantec has selected the SD201P plastic
scintillation detector for continuous measurement of the
beta activity accumulated on the fixed filter media. The
SD201P consists of a NE102 plastic scintillation,
photomultiplier tube, mu-metal shield, dynode chain,
Lucite light pipe, cylindrical enclosure and four foot long
integral cable pigtail. A light emitting diode (LED) is
located in the Lucite light pipe for automatic gain control.
A thermistor located within the Lucite light pipe provides a
temperature signal for temperature compensation. The
detector housing is 2.5” in diameter x 7 inches long. The
detector will be positioned within the lead shielded
sampler for attenuation of gamma background
contribution. |
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| SD Series Detector Specifications: |
| Detector: |
SD201PB NE102 beta plastic
SD220N 2” x 2” NaI crystal |
| Dynamic Range: |
1E+0 to 1E+7 CPM |
| Detector Output: |
Negative Pulse. |
| Accuracy: |
±15% of true field intensity. |
| Linearity: |
±5%. |
| Operating Voltage: |
500 to 1500 V. |
| Nominal LED Bgrnd: |
10–15 CPM. |
| Humidity: |
up to 95% non-condensing. |
| Housing: |
Moisture Proof Stainless Steel. |
| Weight: |
2.7 kg (5 lb). |
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| SDA3E Preamplifier/analyzer |
The scintillation detector detects the accumulated activity
and provides the nuclear pulses to an external SDA3E preamplifier/analyzer unit for pulse analysis. The
preamplifier/analyzer unit analyzes the nuclear pulses,
provides the detector biasing voltage, and performs gain
stabilization. The preamplifier unit communicates with the
skid mounted RM1W display and control unit using
Ethernet communications for display of the measured
activity and for alarm. The SDA3E is a NEMA-4 enclosed
assembly mounted within five feet of the detector. The
analyzer is controlled via the host ratemeter using
software controls to adjust the single channel analyzer
(SCA) window settings such as window width, and
energy threshold. SDA3E settings are maintained in
non-volatile memory to automatically reset the system
after power disruptions. |
| SDA3E Specifications |
| Power Requirements |
| Power Requirements |
max. 250 mA, +/-15 VDC |
| SCA parameters |
| Energy Range: |
100 keV to 2.55 MeV variable In steps of 10 keV |
| Energy Sensitivity: |
100 mV to 2.55 V approx.corresponding to energy |
| Mode: |
Integral or Differential |
| Window Width: |
+/- 1% to +/- 90% around
center energy. |
| Output Signal: |
Positive pulses, 0.5 usec wide
Capable of driving 500 ft |
| Energy Nonlinearity: |
+/-1% of full scale |
Window Width
Accuracy: |
+/-0.5% of energy setting |
| LED Test Signal |
| Equivalent Energy: |
3 MeV |
| Background Rate: |
10 to 15 CPM |
| Environmental
Temperature |
Environmental
Temperature: |
0 to 50 °C, |
Dimensions |
| Dimensions: |
6.25” W x 7.5” H x 5.03” D |
Weight |
| Weight: |
2 lbs. nominal |
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RM1W Display and Control Unit |
The display and control device is the Apantec model
RM1W. The unit is packaged in a NEMA wall mounted
configuration suitable for permanent mounting on the
system skid. The RM1W includes visual and audible
indication of alarm status. Each alarm also has an
associated DPDT relay contact rated at 2A @120VAC.
The following indications will be provided at the front
panel of the unit: |
| CONDITION |
VISUAL |
AUDIBLE |
RELAY |
| HIGH |
Red |
Tone |
DPDT |
| ALERT |
Amber |
Tone |
DPDT |
| FAIL |
White |
Tone |
DPDT |
| NORMAL |
Green |
None |
None |
| CHK SOURCE |
Digital |
None |
DPDT |
| LOW FLOW |
Digital |
Tone |
DPDT |
| AUX |
None |
None |
DPDT |
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Each unit includes a bit mapped digital/analog display,
which is used to indicate both the radiation activity and
operator messages. Radiation activity is displayed digitally
in scientific notation and as an analog bargraph for
trending. The display is autoranging and can be
configured via operator input to display process
information as either Counts Per Minute (CPM) or
engineering units (uCi/cc, Bq/m3). Operator messages are
presented in the digital display to provide information such
as alarm setpoints, error messages, alarm conditions and
instrument status. Operators interface with the unit via a
security keyed membrane switch. By using the MODE,
SET and INCREMENT keys, the HIGH and ALERT alarm
setpoints can be established at any point in the instrument
range. The security keylock switch prevents
unauthorized access to the keypad switch and alarm
setpoints.
Check source activation, lamp test and other diagnostic
functions can be performed without the security keylock.
Each unit also includes analog and digital input/output
signals. Analog 4-20mADC and 0-10VDC inputs/outputs
are provided for interfacing with analog devices such as
recorders. Redundant RS485 serial communications
ports are provided for networking the local units with
remote display and control units. Ethernet
communications ports interconnect the various
radiological sensors to the display unit and for
networking channels for remote display and control. The
power supply is filtered and conditioned for input line
noise rejection and protection from transients and
voltage drop out. A lithium battery backup is maintained
for retention of historical information for a period of up to
200 hours after loss of primary battery power. Critical
system operating parameters are stored in non-volatile
memory for unattended start-up of the system after
power outages.
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| Display and Control Unit Specifications |
| Processor: |
32-Bit High Performance 133Mhz
Integrated Microcontroller Designed for Real-time
and PC/AT-compatible embedded applications
Robust Automotive / Telcom Grade Technology with
Watchdog Timer |
| I/O Processor: |
Dedicated / High
Performance I/O Co-Processing via FPGA/100 Mhz |
| Display: |
240 x 128 pixel bit mapped LCD with
backlight simulates 2 x 20 character display used on
RAM series units Analog/Digital Autoranging and
Autozeroing Alarm/Status Indicators:
| Alarm/Status Indicators: |
| Red indicator: |
HIGH |
| Amber indicator: |
ALERT |
| White indicator: |
FAIL |
| Green indicator: |
NORMAL |
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| Outputs: |
| Digital: |
(3) RS485 |
| |
(1) TCP/IP |
| Ethernet: |
(1) USB , (4) 0-10VDC, or (4) 4-20
mADC isolated |
| Relays: |
DPDT relay contact
for FAIL, |
| |
ALERT, HIGH and MISC alarms |
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Relay contact rating 2A @ |
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115VAC resistive |
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| Power: |
90-260VAC, single phase,47-63 Hz,15 watts |
| Temp: |
-100 to +500 C |
| Humidity: |
up to 95% RH, non-condensing |
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| AS3F Sampler |
The AS3F sampler is provided for monitoring of
particulate and/or iodine activity. The sampler is
shielded with up to three inches of lead arranged in a
4Pi configuration. A detector mount located within the
shield provides a repeatable geometry for the
scintillation detector as well as providing a pressure
boundary. The AS3F sampler is an easy to use design
that uses a fixed filter holder for collection of airborne
radioactive particles and/or iodines. The filter holder accepts industry standard 47 mm diameter filter paper as
well as provisions for use of a TEDA or silver
zeolite cartridge for capture of iodines. When used for
particulate monitoring only, the cartridge is replaced by a
backing screen to provide support for the filter paper. The
scintillation detector, when installed within the sampler, is
in close proximity to the deposited material for maximum
sensitivity. The sampler is constructed of painted cold
rolled steel with corrosion resistant stainless steel used on
wetted surfaces.
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| Low Profile/Vacuum Pumping System |
The monitoring system is provided on a single open
frame skid suitable for mounting to a floor location. Lifting
rings and forklift access are provided for movement of
the system to the monitoring location. The system
includes a vacuum pumping system capable of
generating in excess of 1 SCFM flow. The pump is a
carbon vane progressive cavity or metal bellows pump
with integral fractional horsepower motor. Local ON/OFF
pump controls are provided on the system skid. Remote
pump operations are optionally available. A flow indicator
and flow control valve provide desired flow rate through
the monitoring system. |
| Vacuum/Sampling Specifications: |
| Filter Paper: |
| Particulate: |
47mm to 57mm |
| Iodine: |
TEDA impregnated Type 72 2.25 in. dia (57.1
mm dia) 99% retention of 0.3 micron or larger
particles and iodine at 1 SCFM (30 LPM) |
|
| Vacuum Pump: |
Progressive cavity carbon vane,
diaphragm, or Metal Bellows5 in/hg at 1 SCFM flow |
| Flow Rate: |
0-1 SCFM (0-30 LPM) rotameter
standard, optional thermal mass flow measurement
Accuracy ±15% |
| Flow Totalizer: |
Continuous totalization until reset |
| Power: |
220 VAC, 50/60 Hz, single phase, or 120
VAC, 50/60 Hz, single phase |
| Outputs: |
LOW FLOW Alarms, DPDT Relay, 5A, 120
VAC rated Visual Display on RM1W digital display |
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| Automatic Gain Stabilization |
Apantec scintillation detectors operate with a unique gain
stabilization circuitry for accurate and automatically
compensated detection of activity. Imbedded within the
detector enclosure, and optically coupled to the light pipe
assembly, is an LED and thermistor for gain
compensation. The LED is pulsed at a known low pulse
repetition rate with a known pulse width and amplitude to
provide a reference signal to the SDA3E preamplifier/SCA. The SDA3E contains circuitry that
compares the LED pulses with a reference reading to
provide a feedback for automatic gain compensations
due to drift and aging. The thermistor within the detector
automatically corrects the detector output for variations in
gain due to temperature shifts. This unique feature
extends the calibration cycle of the radiation monitoring
channel and improves system accuracy. |
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