Ludlum Measurements 3000 - Page 40

Model 3000 Survey meter User’s Manual Section 4
Ludlum Measurements, Inc. Page 4-15 April 2021
Setup Page 4
Response Time (Default 0 - auto) – Tap ON/OFF to select the value to be
adjusted and MODE to adjust the value. Setting the Response Time to a fixed
value is useful primarily when performing surveys to a fixed MDA (Minimum
Detectable Activity) level. Setting the Response Time to 0 will enable the Auto-
Response mode for the Model 3000 (see the next parameter). Available values
for the Response Time (in seconds) are:
Ones Place (0-9)
Tens Place (0-6, 6 forces max Response Time of 60)
Auto-Response Rate (Default S) - Tap MODE to select Fast (F) or Slow (S).
When operating in Auto-Response mode, the Model 3000 will vary the
Response Time based on the Auto-Response Rate selected (Fast or Slow) and
the current Count Rate. The following table shows the response time for
different count rates when these auto response modes are chosen:
Count Rate
Auto Response
Time – Fast
(Seconds)
Auto Response
Time – Slow
(Seconds)
Less than 3 kcpm (50 cps)
10.5
21
Between 3 kcpm and 4 kcpm (67 cps)
8.4
16.8
Between 4 kcpm and 6 kcpm (100 cps)
6.3
12.6
Between 6 kcpm and 12 kcpm (200 cps)
4.2
8.4
More than 12 kcpm
2.1
4.2
The Model 3000 also utilizes a Step function in Auto Response mode, which
enables faster response to a significant increase or decrease in Count Rate.
When the instrument detects a sudden change in count rate from the detector,
the response time is reduced to 1 second to quickly show the new value.
Operational Modes (Default 0 - All modes available) - Tap MODE to
adjust the value. Available values are:
0 – RATE, MAX, and COUNT Modes
1 – RATE and MAX Modes only
2 – RATE and COUNT Modes only
3 – RATE Mode only