LB 770 10-Channel α-β Low-Level Counter

The 10-channel Low-Level Planchet Counter LB 770 offers simultaneous, separate α-β measurement of 10 planchets, each up to 60 mm Ø. For each sample there are two separate measuring channels for alpha and beta activities.


Performance:Very low background for alpha, beta; high counting efficiency
Throughput:High sample throughput with 10-fold detector
Reliability:High quality components, 10 detectors available
Ease of use:Easy sample insertion, user friendly yet versatile software
Quality control:Built-in tools for efficiency-, background-, trend checks
Flexibility:Combine quick assessment and low activity measurements
Low Maintenance:Few mechanical parts, maintenance free   

The 10 planchets, each up to 60 mm Ø, are arranged in a matrix consisting of 5 drawers made of copper with 2 samples each. The 10 ultra-flat flow proportional counter tubes are located directly above the planchets. The 10 measuring counters are covered at the top by a large-area flow counter tube acting as common guard counter.

Slider and counter tubes are surrounded by a 100 mm thick shielding made of machined lead bricks (total weight approx. 950 kg). The 11-fold alpha/beta discriminator unit (preamplifier) is located outside the lead shielding. This unit includes in a common housing the pulse preamplifier discriminators with integral discriminators (alpha and beta channels) for direct connection of measuring counter tubes and a discriminator with integral threshold and pulse shaper module for connection of the guard counter tube. It supplies standard pulses to the interface unit.

Simultaneous, but separate counting of 10 samples offers the following major advantages as compared with single detector automatic sample changers:

  • higher throughput or large number of samples
  • the count results are available 10 times faster with equal statistical accuracy for each individual sample
  • with the same overall counting time as before, the statistical accuracy is three times higher
  • instant detection of high-activity outlier samples without having to wait for completion of the counting process
  • extremely low beta background < 1 cpm



Detectors:Suited to measure Ø 60, 50, 30, 25 mm samples, guard counter in antico
Leadshield:10 cm, 4 pi shield to reduce ambient radiation
Preamplifiers:              Excellent alpha beta separation, based on rise time & pulse height discrimination
Counting gas:           Argon-Methane, Argon-CO2
Counting electronics:Interface to PC with HV units for sample and guard detector
Software:Windows software for MS Operating systems 
LB 770-2Single drawer 10 planchets Ø 60 mm
planchets up to 8 mm height
LB 770/5-2Five drawers 2 planchets Ø 60 mm each,
planchets 8 mm height
LB 770/780         Sample changer measuring 10 samples simultaneously,
capacity 250 samples       



Low background system ideally suited for the measurement of alpha / beta emitting nuclides commonly used in these application areas:

  • Environmental labs
  • Health Physics
  • Radio Chemistry
  • Physics
  • Occupationals Health
  • Industrial Safety
  • Food & Drug Analysis
  • Nuclear Medicine

Beta emitters like C-14, P32, P-33, Co-60, Sr-90, Tc-99, Cs-137.
Alpha emitters like Ra-226, Po-210, Th232 are measured with very good efficiency.