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Survey Meter Fluke 451(P/B)
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| "Product PDF 451B" |
| "Product PDF 451P" |
Spicification :
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Fluke Biomedical offers two primary ion-chamber survey meters. The 451P is a pressurized ion chamber for μμR resolution and the 451B includes a sliding beta shield to serve as an equilibrium thickness for photon measurements and enables beta discrimination. Both models are auto-ranging and measure radiation rate and accumulated dose from various radiation sources (451P: x-ray and gamma; 451B: beta, x-ray, gamma). The ion 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.
The digital display features an analog bar graph, 2.5 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. |
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| Radiation detected |
Alpha: > 7.5 MeV
Beta: > 1 MeV (451P);
> 100 keV (451B)
Gamma: > 25 keV (451P);
> 7 keV (451B) |
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| Operating ranges, response time (451P) |
0 μR/h to 500 μR/h (5 sec)
0 mR/h to 5 mR/h (2 sec)
0 mR/h to 50 mR/h (1.8 sec)
0 mR/h to 500 mR/h (1.8 sec)
0 R/h to 5 R/h (1.8 sec) |
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| Operating ranges, response time (451B) |
0 mR/h to 5 mR/h (8 sec)
0 mR/h to 50 mR/h (2.5 sec)
0 mR/h to 500 mR/h (2 sec)
0 R/h to 5 R/h (2 sec)
0 R/h to 50 R/h (2 sec) |
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| Accuracy |
Within 10 % of readings between 10 % and 100 % of full scale indication on any range, exclusive of energy response |
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| Detector |
Chamber (cc volume air
ionization):
230 cc (451P); 349 cc (451B)
Chamber wall (phenolic):
246 mg/cm2 (451B)
Chamber window (mylar):
6.6 mg/cm2 (451B)
Beta slide:
440 mg/cm2 (451B)
Controls: ON/OFF and MODE (451P) |
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| Automatic features |
Auto-zeroing, auto-ranging, and auto-backlight |
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| Power requirements |
Two 9 V alkaline, 200 hours operation |
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| Warm-up time |
Less than two minutes for initial operation when the instrument is in equilibrium with ambient temperature (451P)
One minute (451B) |
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| Display 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 6.4 mm (0.25 in) high. Low battery and freeze indicators are also provided on the display. |
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| 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. |
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Environmental
Temperature range: |
-4 °F to 122 °F (451P);
-4 °F to 158 °F (451B)
Relative humidity:
0 % to 100 % (451P);
0 % to 100 % (at 140 °F) (451B)
Geotropism:
Negligible (451P);
< 1 % (451B) |
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| Typical energy dependence |
16Nitrogen gamma rays are 110 % to 120 % of indicated readings as determined at the University of Lowell |
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| Dimensions (WxDxH) |
10 cm x 20 cm x 15 cm
(4 in x 8 in x 6 in) |
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| Weight |
451P: 1.07 kg (2.4 lb)
451B: 1.11 kg (2.5 lb) |