Fluke Biomedical - Trusted for the measurements that matter to medical industry professionals.
Home  |  Products  |  Radiation Safety  |  Survey Meters  |  

451B Ion Chamber Survey Meter with Beta Slide

Get fast response time to radiation with the 451B's ionization chamber detector

451B Ion Chamber Radiation Survey Meter

451B Ionization Chamber Survey Meter with Beta Slide

The auto-ranging 451B ion chamber survey meter measures radiation rate and accumulated dose from beta, gamma and x-ray radiation sources. The 451B’s site surveying capabilities make it well-suited for a wide range of end users, including: police and fire departments, x-ray manufacturers, government agencies, state inspectors, emergency response and HAZMAT teams, nuclear medicine labs, hospital radiation safety officers, and nuclear power workers. The ionization chamber detector allows for a fast response time to radiation from leakage, scatter beams and pinholes. Additionally, the low noise chamber bias supply provides for fast background settling time. A sliding beta shield serves as an equilibrium thickness for photon measurements and enables beta discrimination. The digital display features an analog bar graph, 2.5 digit digital readout, low battery and freeze (“peak hold) mode indicators, and an automatic backlight function. User controls consist of an ON/OFF button and a MODE button. The case is constructed of lightweight, high strength materials and is sealed against moisture. The RS-232 interface can be connected directly to a computer for use with the Excel add-in for Windows (451EXL), enhancing the functionality of the instrument. This software allows for data retrieval, user parameter selection and provides a virtual instrument display with audible (requires sound card) and visual alarm indication.

Key Features
  • High sensitivity measurement of rate and dose simultaneously, with the capability to record peak rate
  • Auto-ranging and auto-zeroing
  • RS-232 communications interface with optional Windows-based Excel add-in for data logging
  • Ergonomic, anti-fatique handle with replaceable grip, wrist strap and tripod mount
  • Programmable flashing LCD display and audible alarm
  • Easily-accessible battery door (operated by 2 9-volt alkaline batteries) on the outside of the bottom case
  • Available with dose equivalent energy response (SI units)

radiation detector Tested. Meets applicable standards

Product Specifications
Radiation detected:
Alpha above 7.5 MeV, Beta above 100 keV, and Gamma above 7 keV
Operating ranges:
0 to 5 mR/h or 0 to 50 µSv/h
0 to 50 mR/h or 0 to 500 µSv/h
0 to 500 mR/h or 0 to 5 mSv/h
0 to 5 R/h or 0 to 50 mSv/h
0 to 50 R/h or 0 to 500 mSv/h
Within 10% of reading between 10% and 100% of full scale indication on any range, exclusive of energy response. Calibration source is 137Cs
Chamber: 349 cc volume air ionization
Chamber wall: 246 mg/cm2 thick phenolic
Chamber window: 6.6 mg/cm2 Mylar, protected by steel mesh, 46 cm2 detection area
Beta slide: 440 mg/cm2
451B-DE-SI: In order to achieve energy response consistent with measurements of H*(10) as required by ICR4-47, aluminum has been added to the back wall, 38% of the side wall area, and to the beta slide. With the Beta Shield open, the 451B can measure skin dose at 10* (0.07), and Deep Dose H* (10) with Beta shield closed.
Automatic features
Auto-zeroing, auto-ranging, and auto-back
Response time:
0 to 5 mR/h (0 to 50 µSv/h) – 8 sec
0 to 50 mR/h (0 to 500 µSv/h) – 2.5 sec
0 to 500 mR/h (0 to 5 mSv/h) – 2 sec
0 to 5 R/h (0 to 50 mSv/h) – 2 sec
0 to 50 R/h (0 to 500 mSv/h) – 2 sec
Power requirements:
Two 9 V alkaline, 200 hours operation
Warm-up time:
One minute
Integrate mode: Operates continuously 30 seconds after the instrument has been turned on. Integration is performed even if the instrument is displaying in mR/h or R/h
Freeze mode: Will place a tick mark on the bar graph display to hold on the peak displayed value. The unit will continue to read and display current radiation values
LCD analog/digital with backlight
Analog: 100 element bar graph 6.4 cm long. Bar graph is divided into 5 major segments, each labeled with the appropriate value for the range of the instrument
Digital: 2.5 digit display is followed by a significant zero digit depending on the operating range of the instrument. The units of measurement are indicated on the display at all times. Digits are 0.25 in (6.4 mm) high. Low battery and freeze indicators are also provided on the display
Temperature range: Relative humidity: Geotropism: - 4º to + 158ºF (- 20° to + 70°C) 0 to 100%, @ + 60°C Less than 1%
4 (w) x 8 (d) x 6 in (h) (10 x 20 x 15 cm)
2.5 lb (1.11 kg)
Model NameDescription
451B-RYRIon Chamber Survey Meter with Beta Slide and standard chamber
451B-DE-SI-RYRIon Chamber Survey Meter with Beta Slide and dose equivalent chamber

451EXL451EXL 451 Assistant for Excel

Carrying Cases
190HPSSingle Unit Carrying Case (part# 190HPS)

Miscellaneous Accessories
450UCSCheck Source, 238 Uranium, 0.064 μCi, impregnated 2 x 2 in yellow card (part# 450UCS)

Service Packages
Care PlansRequest a quote
Biomedical Equipment  |  Patient Simulator  |  Safety Analyzer  |  Dosimeter  |  Radiation Detector
Related Products
View related products
 451 Assistant for Excel »
 451P Radiation Detector - Pressurized μR Ion Chamber Survey Meter »
 ASM-990 Advanced Survey Meter »
Follow us Fluke Biomedical on Facebook Fluke Biomedical on Twitter Fluke Biomedical on YouTube Fluke Biomedical on LinkedIn Home | Site Map | Fluke Corporation | Terms and Conditions | Privacy Statement | Disclaimer © 1995 - 2017 Fluke Corporation