The auto-ranging 451B measures radiation rate and accumulated dose from beta, gamma and x-ray radiation sources. The 451B뭩 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 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. 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.
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 uSv/h 0 to 50 mR/h or 0 to 500 uSv/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
Accuracy: Within 10% of reading between 10% and 100% of full scale indication on any range, exclusive of energy response. Calibration source is 137Cs
Detector: 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.
Controls ON/OFF and MODE
Automatic features Auto-zeroing, auto-ranging, and auto-back
Response time: 0 to 5 mR/h (0 to 50 uSv/h) in 8 sec 0 to 50 mR/h (0 to 500 uSv/h) in 2.5 sec 0 to 500 mR/h (0 to 5 mSv/h) in 2 sec 0 to 5 R/h (0 to 50 mSv/h) in 2 sec 0 to 50 R/h (0 to 500 mSv/h) in 2 sec
Power requirements: Two 9 V alkaline, 200 hours operation
Warm-up time: One minute
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
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 0.25 in (6.4 mm) high. Low battery and freeze indicators are also provided on the display
Dimensions: 4 (w) x 8 (d) x 6 in (h) (10 x 20 x 15 cm)
Weight: 2.5 lb (1.11 kg)