Description

The Alpha Sentry Continuous Air Monitor (CAM) System resolves many of the issues facing Alpha CAM users today. A patented diffusion screen removes 95% of the unattached radon daughters from the air sample (as much as 90% of the radon daughters are unattached in typical laboratory environments).

In addition, the spectroscopic algorithm (which uses a stripping method instead of ROIs) is extremely effective at subtracting out the radon daughter interference from the transuranic region of interest.

This physical and mathematical radon reduction increases the sensitivity of the Alpha Sentry, which in turn translates into a lower false alarm rate.

The distributed architecture approach taken by the Alpha Sentry CAM system enables the user to monitor potential leak situations from a point safely outside the affected area. Multi-dropping up to eight sampling heads off a single operator interface (ASM1000), enables the location of the sampling heads in the room while the ASM1000 resides in the hallway.

Sharing the operator interface resource lowers the cost per sampling location. It also makes networking to a lab-wide computer easier - there's only one connection per eight sampling heads.

In the Alpha Sentry network, the detector and multichannel analyzer electronics in each sampling head count the activity on the filter and determine if an acute release has occurred. In addition, the ASM1000 reads the spectrum from each head at regular time intervals, applies a precise spectroscopic algorithm, and determines if a chronic release has occurred. In either case, both the sampling head and the ASM1000 signal an alarm.

 

Features

• Patented radon reduction screen
• Patented mass flow meter for accurate air flow measurement
• High sensitivity lowers false alarm rate
• Optional interface to laboratory-wide computer for data transfer
• Precise radon stripping algorithm
• Cleanable, rugged high resolution detector
• Patented disposable filter cartridge assembly saves time and labor
• Distributed architecture reduces sampling location cost
• LCD screen displays spectral data and historical trends
• Continuous self diagnostics ensure system health
• Full compliance with ANSI N42.17B specifications

Description

The ECAM is designed to provide radiological assessments of potential environmental hazards to personnel and members of the public in the event of the release of alpha-emitting radionuclides. ECAM technology allows real-time field monitoring of concentration, DAC-hr and other parameters for determining potential exposure and improving protection of workers, the public, and the environment.

The unit is encapsulated in a durable, weatherproof assembly engineered to survive in various environmental conditions. It houses a vacuum blower capable of pulling 2 CFM, and can be utilized with customer air handling systems up to 120 L/min (>4 CFM) through a filter sample for large air volume data analysis by the ECAM module. Air is drawn into the inlets at the top of the system and passes through a specially-designed miniature cyclone chamber so that debris and large dust particles are forced out of the air stream as it circulates down into the central portion of the instrument where the CAM head is located.

A 1700 mm² PIPS^® detector positioned over the sample filter detects alpha and beta emissions from the sample. Built-in preamplifier and MCA electronics collect alpha and beta spectral data for analysis. Alpha spectrums collected for analysis and Radon compensation are also used to compensate the gross Beta count. Accurate flow data are collected using a patented mass flow meter. The addition of a new 2048-channel Digital Signal Processing (DSP) MCA has expanded the functionality of the ECAM to include compensated gross Beta counting and enhanced Alpha spectroscopy and Radon compensation.

MCA data and sample volume data, as well as instrument status data, are made available for analysis. Data processing for alarm functionality and a graphical user interface are supported by an embedded Pentium®-class single board computer in the ECAM module. A sophisticated background compensation algorithm removes background radon interference to reduce possible false alarms and increase sensitivity.

In addition to performing data analysis, the ECAM module functions as a uniquely-designed web server. This allows easy access to all configuration parameters and provides a convenient method for monitoring throughout an entire local area network via a web browser. A multilevel user security system has been implemented to ensure privacy and prevent accidental misconfigurations by unqualified technicians.

 

Features

• Continuous Air Monitor for Alpha and Beta particulates
• Alpha spectroscopy and gross beta counting
• Optimized for Environmental Air Sampling including windy, outdoor conditions
• Built-in cyclone removes large particles (>20 µm aerodynamic diameter) to focus sampling on the respirable fraction of the sample, extends filter life
• Uniform sample deposition for more accurate alpha and beta detection
• Chronic alarm based on concentration or DAC-hr
• Acute release alarm in as little as six seconds
• Exponential fit and peak fit background compensation algorithms
• Radon compensation lowers false alarms and increases sensitivity
• Compensation for temperature and altitude
• Optional GPS allows dynamic compensation for altitude up to 15,000 feet
• Optional anemometer
• Local and remote audio and visual alarm annunciation
• RadNet compliant with optional encryption and authentication
• Fully functional HTTP server allows for remote monitoring, configuration and calibration
• Optional data output format for compatibility with Lawrence Livermore National Laboratory (LLNL HOTSPOT) plume modeling code

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 CAM 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 >20 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.

 

Features

• 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

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

Description

CANBERRA now offers several new Filter options for the iCAM™ alpha/beta air monitor. These include:

• ICAM/FCF – Millipore® Fluoropore FSLW 3 micron membrane filters – for improved alpha spectrum resolution with consequent reductions in Minimum Detectable Activity (MDA) and false alarm rate.
• ICAM/FCC – For simultaneous beta particulate and molecular iodine monitoring.
• ICAM/FCI – For simultaneous alpha particulate, beta particulate and molecular iodine monitoring.

ICAM/FCF
This new filter card can dramatically improve the iCAMs performance at a low cost. In particular, false alarm rates (already low in iCAM due to the adaptive radon compensation) can be reduced by a factor of up to ten for the same alarm levels and background conditions. This improvement is achieved by replacing the standard GFA filter card with the ICAM/FCF filter, which uses a Millipore Fluoropore FSLW 3 micron membrane filter (as used in the iCAM/MF). This gives far superior alpha spectrum resolution compared to the GFA filter, and so reduces the size of the tails of the Radon and Thoron daughter peaks, thus reducing the background in the U/Pu region and reducing the MDA and false alarm rate. In good operating conditions the standard deviation of the compensated alpha reading (and thus the MDA) is reduced by a factor of >2, and in poor/high background conditions, the improvements are even more dramatic. The table below shows the reduction in MDA using the ICAM/FCF, compared to the GFA filter in good conditions:

Features/Benefits

• > x 2 reduction in MDA, so 4–10 x reduction in false alarm rate
• No changes in setup of iCAM required
• Better results when counted in iSolo®/iMatic™

• A low cost method for beta particulate and molecular ¹³¹I monitoring (non-discriminating)

• A low cost method for alpha and beta particulate and molecular ¹³¹I monitoring (non-discriminating)

As noted above, the improvement under poor conditions is even greater. The better filter spectral resolution will also give better results if the filters are counted off-line after sampling in an iSolo or iMatic.

ICAM/FCC

In this version of the filter card the GFA filter medium is replaced by a charcoal-loaded filter (Whatman type 72). This filter absorbs molecular iodine with very high efficiency, in addition to collecting particulate. 131I, the most common iodine isotope of interest, has several high intensity betas and so will be detected with very high efficiency (~24%) by the iCAM's beta channel.

Iodine occurs in two distinct forms: molecular iodine, i.e. I2, is normally encountered as fission product from fuel or reprocessing. This form is readily collected by a charcoal-loaded filter paper such as ICAM/FCI. The second form is organic iodine, e.g. methyl iodide, more frequently encountered in nuclear medicine. This form is not readily absorbed by a thin filter, so a bulk iodine absorption cartridge must be used (as in the CAM110PIFF). Iodine in the environment is also likely to have exchanged with organic molecules so a cartridge-type system such as the CAM110PIFF should be used for wide area environmental monitoring systems. The ICAM/FCC is not suitable for alpha particulate measurement due to the poor spectrum shape produced, but it is suitable for beta particulate in air monitoring. If simultaneous alpha, beta and iodine monitoring is required then use the ICAM/FCI filter.

ICAM/FCI
The ICAM/FCI filter has both a GFA filter (for alpha and beta particulate) and a type 72 charcoal-loaded filter below it. Using the ICAM/FCI allows an iCAM to monitor for alpha and beta particulates and for molecular iodine simultaneously, with the comments above for the ICAM/FCC filter applying to the iodine monitoring. The only disadvantage of using this filter is the greater pressure drop caused by the two layers, with consequent reduction in the filter life (typically 1–2 days) compared to the lifetime of a standard GFA filter of 5–7 days.

Note, 129I and 125I do not have a detectable beta emission and so will not be detected by an iCAM fitted with the ICAM/FCI or ICAM/FCC filters.

Description

The iCAM/MF moving filter detector head provides iCAM users with an option in filter handling. In place of the fixed, card mounted filter, which must be changed manually at regular intervals, the mechanism passes a continuous belt of filter material under the detector. Hence, when a filter change is required, instead of manual intervention being necessary, the iCAM firmware commands the mechanism to step the filter on, presenting a clean piece of filter material to the detector. The length of the filter roll, combined with the ability of the iCAM compensation algorithms to adapt to filter spectrum shape changes, allows up to twelve months operation with no manual intervention in typical applications. This renders the iCAM/MF ideal for use in hazardous or inaccessible areas where frequent personnel access is undesirable, e.g., long term unattended environmental monitoring. It also allows the iCAM to operate in high dust-loading environments, where otherwise frequent manual filter changes would be required. The sampling head can draw an air sample either directly from the ambient air or remotely via a 1 in. bore hose or pipe connected via the standard iCAM air inlet adaptor.

The mechanism incorporates measurement of the pressure drop across the filter, to assist in determining when a filter change is necessary. The iCAM firmware (V200 or greater) automatically detects the presence of the moving filter mechanism, and can change the filter on any or all of the following conditions:

• Preset time interval
• Preset air volume
• High filter pressure drop
• Low flow
• High activity
• High radon/thoron background

The trigger values for all these conditions are user-settable parameters. Apart from detecting and controlling the moving filter mechanism, the iCAM detectors, firmware and display screens etc. are unchanged. The radon/thoron compensation algorithms operate as in the standard iCAM, but there is a significant improvement in detection performance as the FSLW filter gives better resolution that the standard GFA filter.

The mechanism is compatible with all existing iCAMs and existing fixed filter heads can be replaced with a moving filter mechanism if required.

The mechanism incorporates the same air inlet nozzle as is used on the standard fixed filter iCAM, giving excellent particulate collection performance across a wide range of particle sizes. A source jig is available which allows use of existing iCAM calibration sources with the mechanism. Alternatively customized source jigs can be produced to allow use of suitable alternative calibration sources. For sampling from discharge stacks or process ducts the standard iCAM air inlet adaptor (option ICAM/A) can be used, allowing the connection of a sample pipe.

Features

• Automatic filter change mechanism
• Twelve months autonomous operation
• Fluoropore™ FSLW filter roll
• Filter ΔP measurement
• Retro-fittable to existing iCAMs
• Automatically detected and configured
• For ambient sampling or remote connection via standard air inlet adaptor

Benefits

• Long term unattended operation in inaccessible or unfrequented locations
• Reduced operating costs
• Improved performance - through use of higher resolution filter

Description

The NetCAM has been designed to accommodate modern facilities utilizing networking capabilities to monitor airborne alpha particle activity. By combining the CANBERRA Alpha Sentry Continuous Air Monitor (CAM) sampling head with a specially designed external device providing network support, CANBERRA’s NetCAM resolves many of the issues faced by Alpha CAM users today. These include false alarms due to radon sensitivity, personnel safety, operating cost per sampling location, and remote monitoring capability.

The NetCAM’s sampling head contains a patented diffusion screen that removes up to 95% of the newly-formed radon daughter particles from the air. In addition, the spectroscopic algorithm is extremely effective at subtracting out the radon daughter interference from the transuranic region of interest. This physical and mathematical radon reduction increases the sensitivity of the Alpha Sentry, which in turn translates into a lower false alarm rate. The NetCAM takes advantage of state-of-the-art technology by allowing multiple CAM sampling heads (up to six) to be easily monitored from remote networking stations. This not only improves the safety of personnel by enabling a user to monitor a potential leak situation from outside the affected area, but it also lowers the cost per sampling location by sharing the operator resource.

Each sampling head has a two-fold function in the NetCAM system. The first is to collect airborne particles onto an internal filter and detect any alpha radiation present; the second is to determine the occurrence of an acute release. Air is drawn into the sampling head through the radon rejection screen and through the internal filter by way of a vacuum connection. A Passivated Implanted Planar Silicon (PIPS®) detector is positioned above the filter to detect alpha radiation. Signal processing electronics and a 256- channel multichannel analyzer (MCA) are used to collect and store the alpha spectra. Alpha spectra generated by the MCA in the sampling head are then collected by an embedded PC in the NetCAM via a direct connection to the CAM. The NetCAM reads the spectrum from each sampling head at regular intervals, applies a precise spectroscopic algorithm, and determines if a chronic release has occurred. A sophisticated background compensation algorithm removes background radon interference to reduce possible false alarms and increase sensitivity. In the event either an acute or chronic release is detected, the NetCAM signals an alarm.

In addition to data analysis, the NetCAM provides the operator with a webbased interface, as well as a local VT100™ emulated console for accessing and configuring parameters. This allows easy access to all configuration parameters, as well as providing a convenient monitoring method throughout an entire local area network via a web browser.

An extensive security system ensures privacy and prevents accidental misconfigurations by inexperienced technicians. A series of security levels are assigned to the menus, each corresponding to a certain range of security codes. These codes are then distributed to personnel based upon duties performed and therefore limiting access only to those necessary menus.

Features

• Support for up to six CAM heads
• Eight DAC-hr detection sensitivity to meet 10 CFR 835 Implementation Guide
• Uniform sample deposition for more accurate calculations
• Radon rejection screen and stripping algorithm lowers false alarms and increases sensitivity
• RadNet compliant with optional encryption and authentication
• Fully functional HTTP server allows for easier installation of monitoring sites throughout a network
• Accessible locally through a terminal emulator
• Two PCMCIA slots for optional mass storage or wireless networking
• All analysis and setup functionality housed in an onboard embedded 300 MHz processor featuring:
  • Chronic alarm based on concentration or DAC-hr
  • Sophisticated peak fit and exponential fit background compensation algorithms
  • Local and remote audio/ visual alarm annunciators
  • Access codes for various levels of security
  • Automatic warning for calibrations due
  • Compensation for temperature and altitude