REGIONAL ACCESS
USA ---------------- Benelux Canada France Germany Japan Northern Europe Russia United Kingdom

EXTRANET ACCESS
select a site ---------------- CINET Extranet HIS-20 Extranet HP SW Updates

FEATURES

Engineering:

• Removable, card-mounted filters
• Automatic self-initialization and operation on power on
• Electronic air flow rate measurement, with high and low flow alarms
• Continuous total airflow recording and reporting
• User-set alarms with local and remote reporting
• Simple/automated checks for calibration, gain and spectrum shape
• Software package for full iCAM configuration by local computer or via a network
• Fault diagnostics show on the local display and across the network
• RS-485 and RS-232 communication interfaces
• One-week data storage with detailed event log
• Data is RS-232 and RS-485 transferable to Microsoft Excel
• Thirty minute protection of full functionality by built-in battery backup
• Five years protection of configuration memory

Measurement:

• Continuous monitoring of both alpha and beta activity in air
• Alpha MCA spectroscopy and separate beta discrimination
• Good low energy beta detection
• Auto-adaptive spectrometric compensation for radon/thoron
• Static gamma background compensation with single CAM PIPS detector
• Fully compensated activity alarms
• Three activity levels for primary alarms
• Additional Quick and Long Alarm
• Discharge and discharge rates for duct/stack monitoring

Options

• Trolley mounted system
• Dual CAM PIPS detector version with dynamic gamma compensation
• Full-function area gamma alarm monitor capability using the optional G64 detector
• I/O expansion option provides RS-422 pulse train outputs (compatible with previous Harwell instruments), and also current loop input, optoelectronic outputs and other I/O

Benefits

Engineering:

• A light and compact integrated unit, which is robust, simple to use and easy to maintain
• All the required facilities for alpha and beta monitoring, alarms, data logging, communications and setup
• Sensitive detection of alpha and beta particles plus intelligent adaptive algorithms, for fast, accurate alarms, resulting in high levels of protection and low false alarm rates
• Adaptive spectrometry algorithms and automated checks for high tolerance to variations in background conditions and extended time between filter changes
• Extra alarm facilities for improved management of safety

Description

CANBERRA§s intelligent alpha/beta Continuous Air Monitor (iCAM) provides robust and reliable monitoring of airborne alpha and beta particulate activity in the workplace.
It acts as a simple alarming monitor for operators while measuring airborne activities in real time with the sophistication required to provide low false alarm rates and high protection levels. At the same time it provides automated facilities which assist supervisors to conduct detailed setup and operational overview.

The iCAM measures airborne alpha and beta particulate activity with radon/thoron alpha and beta background compensation. It also provides static or dynamic compensation of beta measurements for gamma background depending on the choice of detector type.

Air is drawn through the instrument by means of an external pump or vacuum system, and airborne particulate material is deposited on the removable card-mounted filter. The filter is monitored by a robust CANBERRA CAMS PIP (passivated ion-implanted planar silicon) radiation detector, which allows simultaneous measurement of both alpha and beta radioactivity in the material deposited on the filter. The air flow is measured directly and reported by the instrument. The design of the airflow system is optimized to ensure high air sampling efficiency and high transmission of particles to the filter. The iCAM has a high detection efficiency for both alpha and beta particles and provides a good sensitivity for low energy beta detection.

Measurement results are presented on the high-visibility graphical display on the instrument§s front panel. User setup and diagnostics are via the local keypad and the graphical display which provide a natural user interface. Results may also be reported via the RS-232 or RS-485 network connections to a local computer or plant surveillance system. Each instrument stores historical data, typically from the previous seven days, which may also be transmitted by network if required. The historical data includes not only activity readings, updated every five minutes in normal operation, but also alarms, filter changes and user interactions. Each event is logged with its date and time.

The iCAM Primary Alarm uses measurements taken over a user selectable interval of typically five minutes, and this data is updated as rolling average every 15 seconds. Alpha, beta and gamma (where applicable) measurement values are each tested against user-set alarm levels. There are three separate sets of three alarm levels, one set of three for each of the alpha, beta and gamma measurement variables. Additional defence against larger emissions of activity in a short time is provided by the Quick Alarm, for which decisions are made on the new data accumulated every 15 seconds.

Finally, iCAM also provides a Long Term Alarm (Chronic Activity Alarm). Here the lowest level alarm may be user-allocated to data accumulated over a long time interval, typically >30 minutes, so that the most sensitive measurements can be achieved. All the alarms are fully compensated for the backgrounds from gamma radiations and from radon/thoron daughter activities.

In addition, any alarms may be indicated locally by visual and audible signals, remotely by relay circuits, or centrally by connection to a suitable monitoring network. Alarm events are also archived.

Hardware

The iCAM instrument is packaged in a rugged steel enclosure which provides IP42 environmental protection and EMC screening. The front panel carries the local controls and indicators, including the high visibility graphical display, the local keypad and the various indicator lights. The RS-232 connector and the alarm sounder are positioned in the bottom third of the front panel. The air inlet and alarm beacons are mounted on top of the instrument.

When the power supply is switched on, the instrument will perform initialization tests and begin normal operation without any operator intervention. It will begin providing valid measurements within 15 seconds after starting normal operation. It will then update measurements at 15 second intervals, whatever the user-set counting interval.

Air is drawn into the instrument at a preset rate, within the range 15-60 L/min (0.5-2.1 ft³/min), typically about 37 L/min (1.3 ft³/min), and particulate material is deposited on a removable filter card. The instrument may be fitted with an adapter for the attachment of a 25 mm (1 in.) pipe. An airflow regulator valve is provided as an option, and the choice of air outlet position may be adopted from either of two connectors: one on top of and one on the bottom of the instrument. The airflow rate is measured directly on board and its value is used to calculate concentration values and integrated concentration values. Low and high flow alarm values can be set by the user. The total air flow since last reset is recorded and reported.

Detectors

A CANBERRA PIPS detector is used for detecting both alpha and beta activity. The single detector version provides static gamma compensation of beta measurements in low or steady gamma background conditions. Optionally, iCAM can come with a dual detector made from two similar detectors in a single housing, with the second detector located very close to the first. This second detector is not exposed to the airflow or filter and instead provides the data to make accurate dynamic compensation measurements for the effect of gamma backgrounds.

The measurement range of the instrument extends to over 500 kBq (13.5 ¦micro;Ci) of combined alpha and beta activity deposited on the filter. A background activity check measurement and display function is provided, which can be accessed via the front panel controls. This check may also be used to identify the presence of contamination within the monitor or to assess ambient gamma background values.

Instrument Annunciators

Five high-brightness indicator lamps draw attention to specific conditions as designated in the table below:

Indicator Name	Indicator Color	Indicator On	Indicator Off
Alarm	Red	An activity alarm condition or a gamma doserate alarm condition has been detected	No activity alarm condition has been detected
Muted	Yellow	The audio alarm has been switched off	The audio alarm has been switched off
Fault	Red	An equipment failure alarm condition has been detected	No equipment failure alarm condition has been detected
ac On	Green	The monitor has ac power	The monitor does not have ac power (It may still be operating - on its internal battery
Monitoring	Green	The instrument is in monitoring mode	The instrument is not in the operating mode

An audio alarm provides indication of alarm or fault conditions. The audible sounder can be muted by use of the local controls without affecting the other alarm indications.

Display

A 240 x 128 pixel (100 x 80 mm) (4 x 3.15 in.) LED-backlit liquid crystal display panel presents operational information, and together with the panel controls, forms a natural interface for the user. It can show ongoing measurement data in various forms, including a live display of the accumulating alpha spectrum. The default is the measured activity levels in the pre-selected units. Alternatively it can be used, together with the panel controls, to show other information and to perform operational functions including calibration check, self tests, and viewing the archive.

Screens

The display shows the current measurement values in the display units selected via the /Display/Measurements soft key.

After power-up, reboot or reset, the instrument will perform initialization tests and begin normal operation without operator intervention. With a filter card in place, the main screen is displayed, showing the activity readings and units (which may be selected from Bq, pCi, CPS, Bq/m³, pCi/L, Bq-hr/ m³, pCi-hr/m³, DAC, DAC-hr). When the instrument is configured as a duct monitor, the units may be in Bq or Bq/h. The units displayed are user configurable. All are measured. The rest of the display shows alarm/status messages, and time and date.

The lowest line of the main example display indicates the status of the four soft keys: the two righthand control keys provide service and maintenance functions and their use suspends normal monitoring. They are therefore accessed under password control. The two lefthand keys provide the operator with more information while normal operation continues uninterrupted.

Archive display may be selected by pressing the archive soft key. It allows the internal measurement and event archive to be inspected on the instrument display. The archive can hold enough entries of normal complexity, for seven days§ data. It includes activity measurements taken at (typically) five minute intervals, user actions such as reset, filter card release or calibration, and records all activity and fault alarms.

The table below shows the logical layout of the other screens. The check screens are protected by password and allow selected operators to conduct instrument checks, which can confirm satisfactory operation according to normal plant operating procedures.

The setup screens are password protected at a higher level. These allow supervisors or designated staff to configure the instrument parameters to match the facility§s operating procedures.

Alarms

iCAM provides visible indication for activity alarms by means of a flashing red beacon on the light stack and a two-tone audio alarm. An internal battery provides backup for the complete instrument operation, including alarm indication and reporting functions of the instrument for ~30 minutes after the loss of mains power. The light stack features a green light that indicates the measuring status of the instrument, i.e., it is in the ¢monitoring¢ condition, when the instrument is taking data. It provides similar information to the ¢monitoring¢ indicator on the front panel, but in a much more highly visible way. In particular, it flashes when the instrument enters the fault condition.

The local annunciation of activity alarms may be enabled or disabled (they are enabled at all levels by default). Irrespective of the annunciator assignment, the panel lights and message display screen also indicate alarm and fault conditions.

Screen Hierarchy

The screen hierarchy is shown below:

Info	Display	Setup	Check
The soft key options lead to a hierarchy of screens as shown in the table	Display options	Password check	Password check
Alarm Current levels	Archive Events Trends	User configuration of instrument parameters Alarm levels Relay levels Fault alarm configurations Measurements and beta compensation Activity measuremnt units Gamma measuremnt units Duct measuremnt units Air flow measuremnt units 4-20 mA current outputs Other parameters	User-initiated instrument check Background Gamma compensation Balance Alpha calibration Beta calibration Air flow calibration Hardware tests
Fault Current fault test status	Current Activity Concentration Duct Quick and Long Backgrounds
	Spectra Data

In responding to alarms or faults, use of the Reset and Mute functions can be open to all staff (the default) or access to these can be restricted by password control, depending on facility operating procedures. This choice can be made in configuration mode.

Relays

The instrument has four relays, each providing two pairs of contacts, operated in a fail-safe mode (i.e., relays are normally energized and contacts normally closed). The relays are allocated by the user and the alarm conditions which actuate the alarm relays are user-configurable. Normally one relay is assigned to fault reporting. The alarm relays also indicate an alarm condition in event of loss of power to the instrument.

Alarm conditions may be latching (default) or non-latching. Latched alarms persist until cleared by user intervention; non-latching alarms automatically reset if the alarm condition no longer exists. Indication of an alarm condition ceases on operation of the reset control. If the alarm condition persists, indication of the alarm will recur as soon as it is recognized.

Activity/Dose rate Alarms

Three alarm levels may be defined for each measurement type; i.e., three alpha activity alarm levels, three beta activity alarm levels, and three levels for gamma dose rate, if appropriate.

When an activity alarm occurs:

• The cause of alarm (alpha, beta, gamma) and the alarm level appear on the display.
• Alarm relays will open or close as programmed for the specific alarm condition.
• A status report may be obtained via the network port which identifies the alarm condition and cause.
• The alarm indicator is illuminated and an audio alert will sound.
• An alarm entry is added to the archive.

Alpha/Beta Activity Alarms

The iCAM provides three types of measurement alarm facility for alpha and beta activity. These can be selected to run at the same time.

Primary Alarm:

This is the alarm used to routinely define the required level of working protection in a facility with optimum time response. It uses the primary measurement values, which are computed on data accumulated over a userselected averaging interval, typically five minutes, with the data updated every 15 seconds. Alpha and beta measurement values are each tested against userset alarm levels (separate sets of three alarm levels for alpha and beta).

Quick Alarm:
To provide rapid warning of emissions of activity in a short time, iCAM also provides a Quick Alarm, made on the data accumulated in the last 15 seconds. Separate single alarms (in cps only) are set at higher levels than the primary alarm levels for both the alpha and beta counting rates.

Long Term Alarm:
When time response is less of a priority, the Long Term Alarm allows the most sensitive and most accurate monitoring, recording workplace activities at the lowest levels.

This alarm uses measurements accumulated over a considerably longer averaging time, (e.g., 30­60 minutes), than the other alarms, but is still updated and tested every 15 seconds. The lowest level of the three primary alarm levels is dedicated to the Long Term Alarm test.

External Dose rate Alarms

The external dose rate measured by the optional G64 gamma monitor detector is computed and tested against the three user-set gamma alarm levels at intervals of one second.

Self Check and Equipment Failure Alarm

The instrument will recognize and alarm on any of the following fault (equipment failure) conditions, each of which can be individually enabled or disabled:

• Low air flow or high air flow (user settable limits).
• Instrument configuration (clock, parameter store, archive).
• Low differential pressure across the filter.
• Detection fault ­ low count rate (alpha/beta, internal gamma, external gamma detector).
• AC power failure.
• Battery and power supply failure.

When an equipment failure alarm occurs:

• The green beacon on the light stack flashes and the audio alarm sounds a continuous tone.
• If configured, the equipment failure relay de-energizes to send a signal to external equipment.

For some faults:

• The equipment failure indicator is illuminated.
• The cause of failure appears on the integral display.
• A status report may be requested via the serial communications port, which identifies the equipment failure alarm condition and cause.
• An equipment failure alarm entry is added to the archive.

Data Archive

The iCAM stores historical data at user-definable intervals. Measurement data, records of the filter changes, alarms and user actions are recorded. Each entry in the archive is marked with the date and time when it was created. There is adequate storage to retain a week§s data (taken on the standard five minute primary alarm interval). Battery protection allows the internal archive data to be retained for five years after loss of mains power.

Air Flow Rate Monitoring

The iCAM electronically measures the air flow rate through the instrument, and the measured value is used in activity calculations. The air flow rate will normally be within the working range of 15-60 L/min (0.5-2.1 ft³/min), and is usually adjusted to be about 37 L/min (1.3 ft³/min) using the (optional) air flow regulator valve. Via the input/output expansion board option, iCAM can provide a 4-20 mA input channel for connection of an external duct flow measurement system. The iCAM can use this signal to calculate the activity discharged and the discharge rate of activity from the duct.

Calibration

iCAM provides facilities to assist and partially automate calibration and the routine checks required by plant procedures to confirm proper operation of such instruments. These facilities are accessed under password control via the check button on the main screen display.

Source Calibration and Testing

Activity measurement calibration checks are performed using test sources in place of the filter card. The sources are mounted on stainless steel carriers of similar dimensions to the usual filter cards, allowing easy insertion. The recommended calibration test sources are manufactured by AEA Technology QSA, with the activity homogeneously incorporated in a thin anodized layer on an aluminium disc. Self-absorption is small and the sources are classified as thin sources according to ISO 2919.

The recommended calibration sources are:

	Alpha	Beta
Nuclide	241AM	31CI
Nominal Emission	160 a/sec	250 b/sec
Nominal Activity	320 Bq (8.6 nCi)	500 Bq (13.5 nCi)
QSA production code	AMRB3135	CIRB3089

No other equipment is required to perform an activity calibration check. Calibration check information and instructions are shown on the LCD and a contamination check, alpha calibration check and beta calibration check can all usually be completed within about 10 minutes.

The background check allows the alpha, beta and gamma background levels to be measured. Raised background levels may indicate the presence of contamination. The background check function is presented at the start of the calibration check operation, and may be bypassed if not required.

These functions provide information about the operating condition of the instrument but does not alter any settings.

Both alpha and beta instrument calibration checks may be performed locally (under password access) using the control buttons and display, and calibration sources which are inserted in place of the filter paper. Detection efficiency, alpha spectrum position and (beta) discriminator settings may be confirmed. Calibration operations are recorded as part of the historical data. The ‘Monitoring§ indicator turns off during calibration and remains off until normal operation is resumed.

Any G64 gamma detector which may be fitted is calibrated separately.

Air Flow Calibration

Each iCAM is supplied with its individual calibration of air flow. This can be checked and reset in plant by a simple procedure involving fitting a calibrated air flow meter in series with a flow regulator valve and the instrument. The iCAM software leads the user through a sequence of successfully setting, measuring and monitoring five values of airflow rate over the 15-60 L/min (0.5-2.1 ft³/min) measurement range. These values are used to (re)calibrate the scale of the internal electronic mass airflow meter.

Changing the Filter Paper

A spring-loaded lever on the instrument is pushed downwards to release the filter card, which can then be withdrawn from the card slot. Monitoring is then stopped and the ‘Monitoring§ indicator turns off and remains off until a fresh filter is inserted by the operator (after first depressing the lever), the instrument is reset and normal operation is resumed. On filter removal, the display will report the elapsed time, the total integrated flow volume and the mean flow rate for that filter. Operation of the filter card lever is recorded as part of the archived data, except during calibration. If no fresh filter is inserted within a preset timeout period after filter removal, usually one minute, then the instrument signals a fault and enters fault mode.

Communications

The instrument is compatible with the Harwell Instruments PCEMS monitoring system and other surveillance systems supporting the Harwell Instruments RS-485 protocol (e.g., Factory Link and other SCADA systems). The surveillance system can then gather information from the monitoring instruments (including measurement data, alarm conditions, instrument status reports and archive data) and adjust instrument configuration parameters.

iCAM provides multi-drop RS-485 network capability, allowing measurement data to be accessed via a dual twisted-pair network cable connection. It also provides an RS-232 communications port, which allows connection to a local terminal (e.g., a laptop PC) for configuration and control. Both ports use the same interface protocol, which is fully compatible with the Harwell Instruments PCEMS environmental monitoring system.

Data available via the network connection includes:

• Real-time alpha and beta activity measurement data
• Real-time gamma dose rate (if G64 head fitted)
• Real-time gamma count rate (dual detector iCAM only)
• Instrument alarm state
• Instrument operational status
• Archive data and spectra
• Configuration parameters
• Calibration state and parameters

iCAM Configuration

A set of configurable parameters define alarm levels, measurement quantities and units, constants used in determining compensated activity levels, calibration source details and password choices for function access. These can be adjusted to suit individual requirements. Parameter values are retained in nonvolatile memory within the iCAM instrument. All configurable parameters are available via the RS-485 and RS-232 network connections. A selection of more commonly required parameters is available for review and change directly via the instrument controls and display. These include alarm levels, measurement units, relay assignments and fault alarm configuration. Access is password controlled.

iCAM instruments are supplied with a Windows^¦reg;- based configuration program for the host computer which provides access to all instrument parameters and allows basic real-time remote monitoring of instrument readings, alarm state and fault status. The configuration program communicates with iCAM using a standard network communications protocol. The software is normally used on a laptop PC and operates with Windows^¦reg; 95, 98 and NT^¦reg;. Connection is usually to the front panel RS-232 port, although the same protocol can be used via the RS-485 port wired via the internal connector block.

iCAM is able to respond independently to the data gathering functions of the configuration software (reading the archive, viewing parameter functions, etc.) which do not interfere with its operation. Configuration functions which alter the characteristics of the instrument (e.g., changing parameter values) cause it to cease normal operation until completion of the configuration changes.

All iCAM instruments provide simultaneous monitoring of both alpha and beta activity. Where alpha-only or beta-only measurement is required, the instruments can be configured to report just these measurements or to measure that activity alone. The user can restore the instrument to provide simultaneous alpha and beta measurement reporting at any time.

Windows and NT are registered trademarks of Microsoft Corporation in the United States and/or other countries.

Products in this Category: RADACS Software (Radiological Assessment Display and Control System)