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

451P Radiation Detector - Pressurized μR Ion Chamber Survey Meter

Ensure radiation safety using our lighweight 451P ionization chamber survey meter

451P Radiation Detector Ion Chamber Survey Meter

451P Pressurized μR Ion Chamber Radiation Survey Meter

The auto-ranging 451P ion chamber radiation survey meter features a pressurized ionization chamber, providing enhanced sensitivity (µR resolution) and improved energy response to measure radiation rate and dose from x-ray and gamma sources. Originally designed to measure leakage and scatter around diagnostic x-ray and radiation therapy suites, the 451P’s radiation measurmenet surveying capabilities make it well-suited for a wide range of end users, including: x-ray manufacturers, government agencies, state inspectors, biomedical technicians, and maintenance technicians for airport baggage scanners.

The ion chamber detector allows for a fast response time to radiation from leakage, scatter beams and pinholes. Additionally, the low noise ionization chamber bias supply provides for fast background settling time.

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 µR measurements of rate and dose simultaneously, with the capability to record peak rate
  • Ergonomic, anti-fatigue handle with replaceable grip, wrist strap and tripod mount
  • Programmable flashing LCD display and audible alarm
  • Easily-accessible battery door (operated by two 9-volt alkaline batteries) on the outside of the bottom case
  • RS-232 communications interface with optional Windowsbased Excel add-in for data logging
  • Available with dose equivalent energy response (SI units)

radiation detector Tested. Meets applicable standards

Product Specifications
Radiation detected
Beta above 1 MeV, Gamma and x-rays above 25 keV
Operating ranges
0 to 500 µR/h or 0 to 5 µSv/h
0 to 5 mR/h or 0 to 50 µSv/h
0 to 50 mR/h or 0 to 500 mSv/h
0 to 500 mR/h or 0 to 5 mSv/h
0 to 5 R/h or 0 to 50 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: 230 cc volume pressurized air ionization chamber to 8 atmospheres or 125 psi
Automatic features
Auto-zeroing, auto-ranging, and auto-backlight
Response time
Analog response time from 10% to 90% of reading for a full scale step increase is dependent on operating range. Response time for a step increase in radiation exposure rate from background:
Step to increase, background to & Time to reach 90% of final value: 400 µR/h & 4.8 sec
4 mR/h & 3.3 sec
10 mR/h & 4.3 sec
40 mR/h & 4.5 sec
100 mR/h & 2.7 sec
1 R/h & 2 sec
4 R/h & 2.7 sec
The following shows time measured from 10% to 90% of final value for a step increase or decrease in exposure rate such that a range change does not occur. These values are the response times for the various ranges:
Range & 10% to 90%: 0 to 500 µR/h (5 µSv/h) & 5 sec
0 to 5 mR/h (50 µSv/h) & 2 sec
0 to 50 mR/h (500 µSv/h) & 1.8 sec
0 to 500 mR/h (5 mSv/h) & 1.8 sec
0 to 5 R/h (50 mSv/h) & 1.8 sec
Power requirements
Two 9 V alkaline, 200 hours operation
Warm-up time
Less than two minutes for initial operation when the instrument is in equilibrium with ambient temperature
Display LCD analog/digital with backlight
Analog 100 element bar graph 2.5 inch (6.4 cm) long. Bar graph is divided into five 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 inches (6.4 mm) high. Low battery and freeze indicators are also provided on the display
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
Temperature range - 4º to 122ºF (- 20° to 50°C)
Relative humidity 0 to 100%
Geotropism Negligible
4 (w) x 8 (d) x 6 in (h) (10 x 20 x 15 cm)
2.4 lb (1.07 kg)
Model NameDescription
451P-RYRPressurized µR Ion Chamber Survey Meter with standard chamber
451P-DE-SI-RYRPressurized µR Ion Chamber Survey Meter with dose equivalent chamber

451EXL451EXL 451 Assistant for Excel

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

Miscellaneous Accessories
62-103Check Source, 137Cs, 10 μCi. Flat disc, 1 inch diameter
(part# 62-103)

Service Packages
Care PlansRequest a quote
Biomedical Equipment  |  Patient Simulator  |  Safety Analyzer  |  Dosimeter  |  Radiation Detector
Related Products
View related products
 451B Ion Chamber Survey Meter with Beta Slide »
 451 Assistant for Excel »
 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 - 2018 Fluke Corporation