1. Design and Mode of Operation of the LB 134
1.1 Overview
The LB 134 is a versatile and flexible instrument designed for
use in radiation protection for contamination, activity and dose
rate measurements. It can be employed whenever alpha, beta
and gamma contaminations on surfaces such as floors, walls,
tables, objects, clothes or the skin, caused by radioactive sub-
stances occur and need to be monitored; moreover, it can be
used to determine the gamma and neutron dose rate. The con-
tamination detectors with scintillator can be used to distinguish
alpha nuclides, on one hand, and beta and gamma nuclides, on
the other hand, and to measure them simultaneously. Further-
more, measuring probes are also available which can be used
to determine CPS values only, as in these cases calibration in
physical units is not possible for various reasons.
The LB 134 includes a microprocessor unit with all the
necessary electronic functions and interfaces, and an internal
gamma dose rate probe. As an alternative to this probe, a varie-
ty of different probes for different measurement tasks can be
connected externally; we then have a combination device that
consists of a basic unit LB 134 and one external probe each,
which is connected to the basic unit via a spiral cable. To ex-
tend the life of the batteries/rechargeable batteries, the supply
of the internal probe is switched off in the menu when not in
use. Nine different detectors can be connected to the UMO
LB 123 which has been on the market for many years; up to 15
detectors can be connected to the new generation LB 134. The
basic instrument identifies the connected detector either via a
code resistor (LB123 UMO probes) or via EEprom memory in
the detector, which communicates via a I²C bus. This means
that the older probes of the UMO LB 123 are compatible. After
the detector has been identified, the corresponding parameters
will be loaded from memory and measurements are performed
with these parameters. Each detector has its own set of param-
eters that can be changed via the LB 134 keyboard or via data
communication.
The LB 134 may be used for the above-mentioned
measurement functions either as a portable and/or as a semi-
stationary device. Special holding devices are provided (e.g.
wall bracket). Single counter events can also be signaled
acoustically, alarms can be communicated visually and audibly
and can be switched on and off. Additionally, these signals can
also be sent to a headphone connected to the device via a jack
plug. In this case, the integrated piezo loudspeaker is disabled.
Alphas and betas can be distinguished acoustically by their
beeps of different lengths. The display backlight can be toggled
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