Annette

Handle: Annette2

Inspector Alert detecting in Counts Per Minute (CPM)

[OLDEST TO NEWEST READINGS IN DESCENDING ORDER]

Submitted on 2012/01/19 at 4:56 pm
Agoura, CA exterior 10-minute averages, using Inspector Alert (a,b,g):
8/13/11, 11:45am – 35.2
8/14/11, 10:20am – 37.9
8/24/11, 1:30pm – 35.8
8/26/11, 5:30pm – 40.7
8/27/11, 9am – 39.7, 42.6
9/6/11, 7pm – 38.9
9/12/11, 12:14pm, 37.0
9/20/11, noon, 38.0
9/24/11, 2:30pm – 40.6
10/3/11, 11:40am – 39.6
10/4/11. 6:40am – 37.6
10/4/11, 12:40pm – 37.0 (jet stream moving in for 1st time in several months)
10/6/11, 12:45pm – 37.5
11/19/11, 4:45pm – 38.3 (damp, foggy dusk)
11/26/11, 1:15pm = 36.3, 5pm = 38.3
12/1/11. 10:45am = 42.7 (Santa Ana’s stirring things up)
12/13/11, 1pm = 37.5 (rained hard yesterday, no long-lived radioisotopes)
12/30/11, 1pm = 38.9
12/31/11, 1pm = 39.3, 2pm = 38.6 (beautiful, clear, sunny day)
1/4/12, 11am = 38.3 (beautiful, clear, sunny & warm)
1/13/12, 11am – 38.3; 2pm – 43.2
1/15/11, noon = 41

Malibu beach sand samples. Collected at Westward Beach from below the surfline; air dried and counted for 10-minutes with unshielded Inspector Alert (a,b,g):

8/26/11 – 5:30pm – BG = 407, CPM = 542, 584 (sand still damp)
8/27/11 – 3:05pm – BG = 425, CPM = 654 (sand dry)
1/13/12 – 2:38 – BG = 408, CPM = 652 (sand collected on 1/5/11)

Westward beach kelp (from surf). Air dried.
1/13/12, 3:16 – BG = 439, CPM = 660 (collected on 1/5/11)

Submitted on 2012/01/22 at 12:16 am

Agoura checking in. Testing results from overnight rain:

These counts are all for the same sample-
7:15am – BG = 47.3, 10-minute average = 75.9
9:30am – BG = 45.5, 10-minute average = 51.1
7:40pm – BG = 43.2, 10-minute average = 42.7

So, excess over background entirely shortlived isotopes that have all decayed away.

Submitted on 2012/01/23 at 10:48 am

Agoura overnight rain (10-minute average run from paper towel swipe of outside glass top table (30″ diameter). Table was cleaned immediately before the rain arrived.

6:50am BG = 421, COUNT = 573
8:30am BG = 446, COUNT = 448
9:10am BG = 482, COUNT = 410

Submitted on 2012/02/07 at 11:28 pm

Was expecting quite the storm. A bit of rain finally arrived in Agoura this evening.
Rain swipe from glass tabletop (cleaned just prior to rain). 10-minute averages, unshielded. Background averages taken just prior and subsequent to sample counts.
8pm
Background = 42.6 cpm, 39.0 cpm
Sample = 62.8 cpm

Same sample retested at 10:30pm
Background = 45.8 cpm, 43.9 cpm
Sample = 40.7 cpm

Short-lived isotopes completely decayed away (and then some, apparently).

Submitted on 2012/02/13 at 2:49 pm
Sampling of Agoura rain. Sampling taken at 11:30am, about an hour after the rain had stopped. A dry wind was blowing that had largely dried any puddles. Sample swipe from glass topped outside table (just cleaned last night) did not soak the paper towel, but the remaining small rain puddle did dampen it. I would think that any deposited particle would still be present after the wind dried the rain (which is what we’re looking for, right)?

Anyway, the 10-minute counts yielded the following data:
11:37am
Pretest Background: 50.7 cpm
Sample: 52.2 cpm (3% & 7% over background)
Post-test Background: 48.7 cpm

1:45 am retest
Pretest Background: 45.2 cpm
Sample: 44.7 cpm (1% under and 5% over background)
Post-test Background: 42.4 cpm

*Keep in mind the Inspector Alert has a 15% margin of error in these count ranges.

Submitted on 2012/02/15 at 10:37 pm
Agoura rain. The first 10-minute average was alarmingly high, but did proceed to decay away to background over the next few hours.

3:10pm
Background = 45.6 cpm
Sample = 140.2 cpm
Background = 47.7 cpm
5:54
Background = 44.6 cpm
Sample = 47.1 cpm
Background = 41.0 cpm
Sample = 44.9 cpm
9:30pm
Sample = 44.9 cpm
Background = 46.3 cpm

Submitted on 2012/03/07 at 9:02 am
Agoura, CA – 8:30am

Exterior 10 minute average = 41.7cpm