Model 451P 輻射儀Pressurized μR Ion Chamber Survey Meter

High sensitivity μR measurements of exposure ａnd exposure rate

Available with dose equivalent energy response （SI units）

Fast response to measure radiation from leakage, scatter beams ａnd pinholes

Ergonomic, anti-fatigue handle with replaceable grip ａnd wrist strap

Excel add-in for Windows ® for data logging ａnd selection of instrument operating

parameters （optional）

Low noise chamber bias supply for fast background reading

Choice of bright, highly visible colors

Easy touch keys

INTRODUCTION

The Model 451P state-of-the-art ion chamber survey meter is a hand-held battery

operated unit designed for use in both rugged ａnd normal environments. The

Model 451P features a pressurized ionization chamber, providing enhanced

sensitivity ａnd improving energy response to measure gamma ａnd X-ray radiation.

The Model 451P employs microprocessor ａnd LCD technology. The ergonomic

handle, features a large diameter cushioned grip ａnd is designed to reduce fatigue

associated with extended use. The case is constructed of lightweight, high strength

materials ａnd is sealed against moisture. The user must specify R or Sv when

ordering.

The display features an analog bar graph, 2 1/2 digit digital readout, low battery

and freeze mode indicators. User controls consist of an ON/OFF button ａnd a

MODE button. The unit is auto-zeroing ａnd auto-ranging. The display features

circuitry that automatically activates the backlight in low ambient light conditions.

The RS-232 interface can be connected directly to a computer for use with the

Excel add-in for Windows ® , enhancing the functionality of the instrument. The

software allows for data retrieval, user parameter selection ａnd provides a virtual

instrument display with audible （requires sound card） ａnd visual alarm indication.

The software may be customized by the user for specific applications.

APPLICATIONS

The Model 451P is used in a wide range of medical ａnd health physics applications.

The Model 451P was designed to measure leakage ａnd scatter around diagnostic

X-ray ａnd radiation therapy suites. Also, the Model 451P is ideal for site surveys

and is regularly used by X-ray manufacturers, government agencies, state

inspectors,

research labs, biomedical technicians, ａnd in airports for baggage inspection

equipment maintenance.

FEATURES

• Ideal for a wide range of applications including NDT, X-ray, ａnd environmental

• Battery operated

• Auto-ranging ａnd auto-zeroing

• RS-232 communications interface

• Measures rate ａnd dose simultaneously

• Tripod mount for stationary, area monitor applications

• Freeze mode indicates peak reading

• Programmable flashing display

• Automatic, ultra-bright LCD display

• Separate integrate mode

• Excel add-in for Windows ® （optional）

• Real-time data logging

• Downloading of 2700 data sets stored in instrument

• Virtual instrument display with audible ａnd visual alarm indication

• Supports user instrument configuration ａnd parameter selection

• User selectable modes

SPECIFICATIONS

Radiation Detected

Beta above 1 MeV

Gamma ａnd X-rays above 25 keV

Operating Ranges

0-500 μR/h or 0-5 μSv/h

0-5 mR/h or 0-50 μSv/h

0-50 mR/h or 0-500 μSv/h

0-500 mR/h or 0-5 mSv/h

0-5 R/h or 0-50 mSv/h

Accuracy

Within 10% of reading between 10% ａnd 100%

of full scale indication on any range, exclusive

of energy response. Calibration source is 137 Cs

Detector

Chamber: 300 cc volume pressurized air

ionization chamber to 6 atmospheres

Controls

ON/OFF ａnd MODE

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 increase,

background to

Time to reach 90% of

final value （seconds）

400 μR/h 4.8

4 mR/h 3.3

10 mR/h 4.3

40 mR/h 4.5

100 mR/h 2.7

1 R/h 2

4 R/h 2.7

The following table 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% - 90%

（seconds）

0-500 μR/h （5 μSv/h） 5

0-5 mR/h （50 μSv/h） 2

0-50 mR/h （500 μSv/h） 1.8

0-500 mR/h （5 mSv/h） 1.8

0-5 R/h （50 mSv/h） 1.8

Power Two 9-volt alkaline, 200 hours operation

Display LCD analog/digital with backlight

Analog100 element bar graph 2.5 in （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 1/2 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

1/4 in （6.4 mm） high. Low battery ａnd freeze

indicators are also provided on the display

Warm-Up Time

Less than two minutes for initial operation when

the instrument is in equilibrium with ambient

temperature

Environmental

Temperature Range - 20°C to + 50°C

Relative Humidity 0 to 100%

Geotropism Negligible

Typical Energy Dependence

16 Nitrogen gamma rays are 110% to 120% of

indicated readings as determined at the University

of Lowell

Dimensions 4 in （w） x 8 in （d） x 6 in （h） （10 x 20 x 15 cm）

Weight 2 lb 6 oz （1.07 kg）

451P Models

Model 451P-RYR 451P w/standard chamber

Model 451P-YGG 451P w/standard chamber

Model 451P-DE-SI-RYR 451P w/Dose

Equivalent chamber

Model 451P-DE-SI-YGG 451P w/Dose

Equivalent chamber

Suffix designation RYR = Red/yellow/red

Suffix designation YGG = Yellow/gray/gray

Options Model 451EXL Excel add-in for Windows ®

and RS-232 interface cable

Model 190HPS Single Unit Carrying Case

Model 190HPC Multiple Unit Carrying Case

Model 62-103 137 Cs 10 μCi Check Source

Modes 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

Model 451P Typical Energy Dependence

Indicated/ Actual

Effective （keV）

Specifications are subject to change without notice.

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