Chapter 2: General Operation; Starting The Radiation Alert® Frisker; Units Of Measurement; Maximum Level - SE Radiation Alert Frisker Operation Manual

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Chapter 2: General Operation

Starting the Radiation Alert® Frisker

Before starting the Radiation Alert® Frisker, install 2 standard AA alkaline batteries in the battery compartment

located in the lower rear of the handle (Figure 1(1)).

To start the Radiation Alert® Frisker, set the power switch to On (I) or Audio (A). The Radiation Alert® Frisker

will then beep and begins a 6-second system check. SEI Frisker, the serial number of the unit, and the

firmware version are displayed. After the system check, the radiation level is displayed in the selected mode.

Approximately 30 seconds after you start the Radiation Alert® Frisker, a short beep indicates that enough

information has been collected to ensure statistical validity.

The Radiation Alert® Frisker is designed for use of conventional units; microroentgens per hour (µR/hr),

milliroentgens per hour (mR/h), counts per minute (CPM), nanosieverts per hour (nSv/h), microsieverts per

hour (µSv/h), and counts per second (CPS). To switch between units of measure, push the MODE button,

located to the right under the LCD display. (Figure 1(1))

Though the Frisker is only calibrated to 50mR/hr, it will detect levels much higher than that. The maximum

value to make it over range is related to the dead time and the sensitivity. Typically, the dead time is about

40 µseconds (1/4E-5) and the sensitivity is around 3600 cpm/mR/hr (60cps/mR/hr). With these settings, the

Frisker will over range at (1/4E-5)/60 = 417 mR/h.

When the maximum level for the current mode is reached, the Radiation Alert® Frisker beeps for 3 seconds,

pauses for 3 seconds, and repeats that pattern. Also, the ALARM icon is displayed and the numerical values

displayed will show 0000 instead of the specific rate. The beeping pattern will continue until the level

decreases or the Radiation Alert® Frisker is turned off.

When the radiation level is less than 6,000 CPM, the reading in any of the dose rate modes is based on the

radiation detected in the previous 30 seconds. In order to give a quicker response to changes, when the

radiation level exceeds 6,000 CPM in any 30 second period, the reading is based on the previous 6 seconds.

After 30 second start-up

if instrument is detecting

(<100 CPS)

<6000 CPM or <1.75 mR/hr

(100 -200 CPS)

6000-12,000 CPM or 1.75-3.6 mR/hr

The reading will be based

on an average of the previous

30 seconds

6 seconds

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