Radiation Meters - Mini Instruments

The 900 Series - Monitors for radiation control
The mini-monitor is well established in teaching, research, hospital and industrial laboratories as a reliable, convenient and inexpensive radiation meter.

The 900 has the following features:

• A large logarithmically scaled meter with an open scale at the lower end to show background levels of radiation while displaying high levels without switching
• A speaker to give an audible estimate of radiation intensity
• An alarm which can be set to trip any level on the scale
• Battery or mains operation using a separate power unit. Included is an internal constant current charger for rechargable batteries
• Lightweight aluminium case
• A comprehensive manual containing tables and curves of response to different radiations and other useful information
• The monitor conforms to the requirements of the International Technical Commission publication 325

Specification

Weight	1.0kg
Size	180W by 110d by 165h mm overall
Batteries	6 type AA cells, alkaline (IEC LR6) or rechargable (IEC KR15/51)
Battery life	Approximately 300 hours at 4 hours/day
Paralysis time	Scale corrected to give true reading
Meter integration time	1 to 4 seconds set to match counting rate
Radiation detector	Halogen quenched G-M tube
Radiation detected	Gamma and X-rays only
G-M tube supply	300-700 Volts preset for tube type
Overload protection	No meter 'fallback' with intensities at least 100 times full scale reading
Mains power	12-18 Volts D.C. from mains unit
Energy response	Exposure based response of types R, G & D. Consult factory for ambient dose equivalent response versions

Type RA
A monitor scaled over the range 0.5 to 5000uSv h-¹ (0.05 to 500mR/h). The G-M tube is compensated to give a useful response from 45 keV to 1.5 MeV and above. It is not recommended for monitoring X-radiation from apparatus operating below 75kVp.
Price: £810.70

Type GA
A sensitive instrument for environmental use. The monitor is scaled over the range 0.05 to 75uSv h-^{1 (0.0005 to 7.5mR/h). The useful energy range is 55keV to 1.5MeV and above. This instrument is not suitable for monitoring X-radiation.}
Price: £943.80

Type DA
A monitor using a partially compensated G-M tube to obtain an extended low energy response. The instrument is scaled over the range 0.5 to 1000uSv h-^{1 (0.05 to 100 mR/h). The useful energy range is from 30keV to 1.5MeV but response is maintained down to at least 17keV. It is suitable for measuring radiation from X-ray apparatus operating at or above 45kVp.}
Price: £874

Type X
This instrument is scaled to 0.5 to 2000 counts per second and uses an end window G-M tube without energy compensation. It is sensitive to radiation down to 10keV and is terefore useful for locating X-ray leakage from a variety of systems including high voltage equipment where X-rays are generated adventitiously. It is not intended for measurement but as a relative check device.
Price: £879

The 900 Series - Monitors for contamination control
The mini-monitor is well established in teaching, research, hospital and industrial laboratories as a reliable, convenient and inexpensive contamination meter.

The 900 has the following features:

• A large logarithmically scaled meter with an open scale at the lower end to show background levels of contamination while displaying high levels without switching
• A speaker to give an audible estimate of radiation intensity
• An alarm which can be set to trip any level on the scale
• Battery or mains operation using a separate power unit. Included is an internal constant current charger for rechargable batteries
• Lightweight aluminium case
• A comprehensive manual containing tables and curves of response to different radiations and other useful information
• The monitor conforms to the requirements of the International Technical Commission publication 325

Specification

Weight	1.0kg
Size	180W by 110d by 165h mm overall
Batteries	6 type AA cells, alkaline (IEC LR6) or rechargable (IEC KR15/51)
Battery life	Approximately 300 hours at 4 hours/day
Meter range	0.5 to 2000 counts s-1 for types E, EP15FL, S and SL, 0.5 to 600 counts s-1 for types EP15
Paralysis time	Scale corrected to give true reading
Ratemeter integration time	1 to 4 seconds set to match counting rate
Radiation detector	Halogen quenched G-M tube for all types except EL which is organic quenched
G-M tube supply	300-700 Volts or 600-1500 volts internally preset for tube typepreset for tube type
Overload protection	No meter 'fallback' with intensities at least 100 times full scale reading
Mains power	12-18 Volts D.C. from mains unit

Monitors are delivered complete with alkaline batteries, G-M tube and instruction manual. Rechargable batteries are fitted on request. mains power units are available for all series 900 monitors.

Please note: 1Bq Cm-¹ = 2.7 x 10-⁵ uCi cm-² Sensitivity data derived from tests carried out by the NRPB. Contamination response figures are given for a probe to source distance of 1cm.

Type E
A general purpose monitor using a thin end window G-M tube. It is suitable for the monitoring of soft beta emitters. Under certain conditions surface beta and gamma dose rates may be estimated. The probe is supplied with a protective grille and plastic end cap.

Price: £826

Type EP15
Similar to the type E but using a large end window halogen quenched G-M tube. It is approximately twice as sensitive as the type E but has a lower scale limit and is recommended for measuring the lower contamination limits of soft beta emitters. The window is protected by a stainless steel grille and removable plastic cap.

Price: £874

Type SL
A monitor using a slide window G-M tube. Suitable for bench and personal monitoring of hard beta and gamma contaminants. The stainless steel holder can be used for beta-gamma discrimination. The type SL monitor is similar but uses a tube with an active length of 60mm and approximately half the sensitivity.

Price: £814.00

Type EP15FL
The EP15FL uses the same G-M tube as the EP15 and has a similar response. The tube is housed in a rugged aluminum holder which has been primarily designed foe industrial use. The meter is scaled 0.5 to 2000 counts s^-1

Price: £947

The 900 Series Mini Monitor
Scintillation Monitors for contamination control

The mini-monitor is well established in teaching, research, hospital and industrial laboratories as a reliable, convenient and inexpensive contamination meter.

The 900 has the following features:

• A large logarithmically scaled meter with an open scale at the lower end to show background levels of contamination while displaying high levels without switching
• A speaker to give an audible estimate of radiation intensity
• An alarm which can be set to trip any level on the scale
• Battery or mains operation using a separate power unit. Included is an internal constant current charger for rechargable batteries
• Lightweight aluminium case
• A comprehensive manual containing tables and curves of response to different radiations and other useful information
• The monitor conforms to the requirements of the International Technical Commission publication 325

Specification

Weight	1.0kg without probe
Size	180W by 110d by 165h mm overall
Batteries	6 type AA cells, alkaline (IEC LR6) or rechargable (IEC KR15/51)
Battery life	Approximately 120 hours at 4 hours/day
Meter range	0.5 to 5000 counts s-1
Paralysis time	Scale corrected to give true reading
Ratemeter integration time	1 to 4 seconds set to match counting rate
Radiation detector	Most portable scintillation probes having a single cable termination are suitable
HV supply	600-1500 volts set internally
Overload protection	Provision to indicate excess tube current
Mains power	12-18 Volts D.C. from mains unit

Gamma Scintillation Probe Type 41
Sodium iodide crystal 19mm dia by 25mm thick. Suitable for energies from 25keV upwards. A lead cylinder surrounds the crystal giving the probe directional properties as well as reducing background

Diameter 400mm length 210mm
Sensitivity 10uSv h^-1 (1mR/h) ¹³⁷CS approx 1000 counts s^-1
3.7kBq (0.1uCi) of ^99mTc at 20mm approx 130 counts s^-1
Background 3-8 counts s^-1 depending on locale

Price: £1500

Gamma Scintillation Probe Type 41S
Similar to type 41 but without lead shielding and has a larger sodium iodide crystal (25mm dia by 38mm thick) for increased sensitivity. Suitable for energies from 25keV upwards. The probe is essentially omni-directional for medium and high energy gamma radiation.

Diameter 38mm length 217mm
Sensitivity 10uSv h^-1 (1mR/h) ¹³⁷CS approx 3500 counts s^-1
Background 20-30 counts s^-1 depending on locale

Price: £1630

X-Ray Scintillation Probe Type 42A
Sodium iodide crystal 23mm dia by 1mm thick with a 14mg cm^-2 aluminum window.. This probe has a higher sensitivity than the type 41 for gamma energies below 60keV to a minimum of 10-15 keV. An integral lead colliator makes it particularly useful for ¹²⁵I thyroid monitoring and deep vein thrombosis location.

Diameter 40mm length 187mm
Sensitivity 3.7kBq (0.1uCi) of ¹²⁵I at 20mm approx 330 counts s^-1
Background 2-3 counts s^-1 depending on locale

Price: £1364.00

X-Ray Scintillation Probe Type 42B
This probe is the beryllium window version of the type 42 and detects very low gamma energies down to 5keV. The response above 15keV is almost identical to the 42A.
Window weight 47mg cm^-2.

Price: £1507.00

Scintillation Probe Type 44A
The sodium iodide crystal (32 mm dia by 2.5mm thick) is mounted on the front surface of the probe to facilitate monitoring of large contaminated areas. It is suitable for a range of energies from approximately 15keV to 250keV. It is also beta sensitive for energies above 500keV.

Diameter 50mm Length 180mm. Aluminum window weight 14mg cm^-2.
Sensitivity 3.8, 1.6 & 1.4 counts s^-1 for 1Bq cm^-2 (2.7 x 10-⁵uCi cm^-2) of ¹²⁵I, ^99mTc, ⁵⁷Co respectively.
Background 4-8 counts s^-1 depending on locale

Price: £1370

Scintillation Probe Type 44B
This probe is the beryllium window version of the above and extends the sensitivity down to approximately 5keV making it useful for ⁵⁵Fe. 3.7kBq (0.1uCi) of ⁵⁵Fe at 10mm approx 180 counts s^-1. Window weight 47mg cm^-2.

Price: £1700

Electrical Specification

Socket outlet	Single PET 100 series for single output + H.V. supply
Dynode chain	approximately 55Mohms
Preamplifier	sealed unit giving a maximum of 1 volt negative pulse into a minimum load of 1000 ohms. No supply required
Pulse decay time	2.5us in above load
Current consumption	approximately 17uA at 1000 volts

Unless otherwise stated, none of theses probes are suitable for the detection of alpha or beta radiation.

Portable Alpha Monitor
1800 series with internal probe

• Sensitive, stable scintillation counter
• Easy handling decontamination
• Industry-standard probe configuration

The 1800 deries Portable alpha Monitor is designed for easy, single-handed use in sweeping areas of potential alpha contamination. It incorporates a high-efficiency ZnS(Ag) scintillator for high alpha sensitivity with excellent rejection of beta/gamma radiation. Industry-standard probe format (127x120mm) conforms to common calibration jigs and eliminates any necessity to alter current practices and working procedures.

The 1800 PAM can rapidly detect alpha contamination of surfaces and workpieces, providing an audible click for each detected pulse, and can be used to monitor gloves and hands as an exit monitor via a separate (optional) holder.

Operating principle
Based on well proven ZnS scintillator and photo-multiplier technology, the 1800 series PAM is ideal for monitoring work surfaces, benches, personnel and their belongings at boundary points. Simple, error-free readings are provided by a clear log-scaled meter, supplemented by an audible indication per pulse. Alpha contamination equivalent to 37Bq of ²³⁹Pu over an 100cm² area gives a reading of around 8 cps on the meter, whereas the meter is practically unresponsive to Beta/Gamma radiation.

The probe is shielded by a fine mesh grille over the vunerable window which maintains sensitivity while allowing measurements in typical industrial environments. Our unique design gives a true 100cm² window within the same probe outline as others, with a very simple procedure for replacing hte window or even the entire probe assembly, should that ever be necessary.

The fast respons of the instrument gives users confidence that sweeping large areas and frisking clothing will detect contamination rapidly and that an immediate warning signal will be given. Any overload condition results in continuous tone output and full-scale meter deflection.

In use, the instrument is light-weight and easily operated in one hand, even inside a bag. The tough polyurethane moulded case is designed to be easy to decontaminate and to surveve typical industrial environments. Full EMC protection is provided by an internal RFI shield coating.

Smart ION
Advanced ion chamber survey meters - from £1492.7
The Smart-ION is a microcomputer-based instrument of advanced design for the measurement of Gamma, Beta and X-ray radiation.

The Smart-ION provides functions previously not available in meters of this type, including data logging, alarm, remote calibration and security features. Operation is simple, reliable and maintenance-free, and the instrument is housed in a robust case.

Sensitive ion chamber
The ion chamber has a capacity of 450cm³. Measurement in mixed beta/gamma fields is simplified by the moveable beta shield. This is 550mg cm² plastic. The Ambient Dose Equivalent (Svh^-1) version is corrected for a response of H (0.07) from 10KeV with the shield open and H*(10) from 22KeV with it shut. The 7mg-cm² window density permits accurate measurement of beta dose rates in the energy (Emax) range 150KeV to 2.5MeV. The chamber is vented to the air volume within the instrument and thence to atmosphere.

Electrometer with minimal leakage and drift
The electrometer is based upon a low-leakage MOSFET operational amplifier. Special guard-ring techniques and packaging pin-out keep offset leakage to a minimum. Careful matching and circuit design minimise zero drift with temperature. Zero adjustment is established by microcomputer control: pressing the zero button engages a precision digital servo loop adjustment.

Measurement in uSvH^-1, uGyh^-1 and mR/h
These versions of the Smart-ION are available to suit the units of measurement required.; For air kerma measurement the display is in uGyh^-1. For exposure-based response measurement is in mR/h. For ambient dose equivalent H* (10) the display is in uSvh^-1. In each case the ion chamber response is configured at manufacture.

Data logging by random or pre-ordered routes.
Doserate data from random surveys can be stored in up to 400 storage locations. Ordered location surveys are organised by downloading 4-character locations before issue from from a PC file (ASCII) through an optional infra-red interface umbilical. Interfacing software is also available. The memory inside Smart-ION is non-volatile through switch-off, as is the internal millenium-proof clock.

Audible alarm preset.
A doserate alarm is provided which may be set from 10% of the lowest range through 61/2 decades to 100% of the highest range.

Large character LCD digital and analogue display
The doserate is displayed in characters 1cm high on a custom-made liquid crystal display, with the appropriate units and locational code, if any. The wide simulated analogue scale has 50 segments clearly indicating doserate trends. Status indications show battery condition, ion chamber bias and beta shield position.

Local/Remote calibration, and Interlocks
Local calibration is provided for use with beta sources, and a suitable jig is available. Up-Down keys obviate an insecure screwdriver adjustment, whilst the infra-red link to a remote PC allows the meter to be safely tested with high intensity gamma sources. The supervised PC link also offers:

• the calibration to be locked out of operator interference
• adjustment or locking the alarm
• clock adjustment
• a battery-saving time-out
• access to certain engineering adjustments

Easily-accessible function keys
The wipe-clean membrane keys offer easy access to the wide-range of functions. Some can be locked-out using the PC remote interface to protect calibration and alarm settings, route codes and backlight timer from unauthorised tampering.

Over 100 hours battery operation
The energy-conscious design uses two 'D' size alkaline cells, with chamber bias and clock back-up using very long-life Lithium cells.

Tough moulded case and handle
The case is moulded in haed-wearing wipe-clean ABS/polycarbonate with easy external access to a separate battery compartment.

Three Varients
The better to meet the needs of various industries and safety regimes, the following varients are offered, each scaled for the above choice of units over the five standard ranges from the minimum indication of 0.1uSvh^-1 (0.01mR/h) to a maximum 500mSvh^-1 (50R/h) and over range alarm.

Range locking models 2100S, -G or -R.
If the expected doserate is greater than the current displayed range, you can use this feature to set the meter on the required range. This will reduce the autoranging time. Any of the five ranges can be selected. This feature is useful in situations where the range-changing delay could be hazardous, e.g. where high intensity, collimated beams are encountered.

Integrate models 2120S, -G or -R.
This model includes two integrating (dose) ranges: 0.50 uSv and 0.5000 uSv. This version is suitable for measuring radiation from linear accelerators and pulsed x-ray systems.

Barcode model 2149S, -G or -R.
In addition to the standard features of the 2100 the extra provision is an integral bar-code reader. By placing bar-code placards at analysis points, the dose rate encountered can automatically be registered in memory against the actual location. Software can be provided for interfacing to windows based dosimetry and plant management systems.