• Direct measurement of artificial alpha/beta radioactivity with compensation of radon products by ABPD & AED compensation method
  • Transportable monitor with small footprint
  • Si-CAM detector unit 600 mm² for simultaneous separate alpha/beta measurement 


  • Continuous filter operation with 4 selectable speeds from 5 to 15 mm/h, warning before paper end
  • Step filter operation optionally possible
  • Low-noise and low-maintenance pump unit with failure monitoring

Self-Checking & Alarming

  • Monitoring of the pump function
  • Monitoring of the filter tape
  • Detector failure threshold alpha and beta (and gamma if installed)
  • Pre-Alarm threshold alpha or beta
  • Alarm threshold alpha or beta
  • Lamp test

Product Overview

LB 9140

Monitoring concept

The particulates monitor LB 9140 is used to measure airborne Alpha-/Beta particulates in the presence of naturally occurring (Radon) activity and fluctuating gamma backgrounds.

The portable monitor consists of following main building blocks:

  • Dust collection unit 9128µ: allows the prompt measurement of radioactive Alpha-/beta particles using Si-CAM detector
  • Prompt Alpha-/Beta detector: measures directly on the collection area to have a real time monitoring system
  • Cassette: made of aluminum with protection degree IP68 envelopes the dust collection unit, filter supply and take-up spools. A plexi-glass front door allows visual inspection of the filter supply on the feed spool.

The filter advance is driven by a stepper motor unit, which allows continuous advancement of the filter tape at user selectable speeds (5/10/12.5 and 15 mm/h). Alternatively the filter can be advanced in step wise mode with user selectable time intervals.

Read More

LB 9140 the filter monitor zoomed

Filter Monitor

Technical Data

Structural shape300 x 300 x 530 mm³ (W x D x H)
Dust collection area25 x 25 mm²
Construction materialalum side & back plate, Plexiglas cover front

glass fiber particulates filter to DIN Whatman N° 10

roll 12 m x 50 mm, Core 25 mm diameter

Autonomy> 3 months at 5 mm/h speed
Pump Unit 

low maintenance (> 10.000 h)

silent operation (< 60 dB(A) at 1 m)

pump head max. -440 mbar

typical operating -160 mbar

Flow ratetypical 3.3 m³/h at NTP

data logger LB 5340

(Refer to LB 5340 Flyer)