We describe an experimental setup for making precision measurements of relative β-decay rates of 22Na, 36Cl, 54Mn, 60Co, 90Sr, 133Ba, 137Cs, 152Eu, and 154Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate.

1.
E.
Fischbach
,
J. B.
Buncher
,
J. T.
Gruenwald
,
J. H.
Jenkins
,
D. E.
Krause
,
J. J.
Mattes
, and
J. R.
Newport
, “
Time-dependent nuclear decay parameters: New evidence for new forces?
,”
Space Sci. Rev.
145
,
285
-
335
(
2009
).
2.
J. H.
Jenkins
,
E.
Fischbach
,
J. B.
Buncher
,
J. T.
Gruenwald
,
D. E.
Krause
, and
J. J.
Mattes
, “
Evidence of correlations between nuclear decay rates and Earth-Sun distance
,”
Astropart. Phys.
32
,
42
-
46
(
2009
).
3.
D.
Javorsek
II
,
P. A.
Sturrock
,
R. N.
Lasenby
,
A. N.
Lasenby
,
J. B.
Buncher
,
E.
Fischbach
,
J. T.
Gruenwald
,
A. W.
Hoft
,
T. J.
Horan
,
J. H.
Jenkins
,
J. L.
Kerford
,
R. H.
Lee
,
A.
Longman
,
J. J.
Mattes
,
B. L.
Morreale
,
D. B.
Morris
,
R. N.
Mudry
,
J. R.
Newport
,
D.
OKeefe
,
M. A.
Petrelli
,
M. A.
Silver
,
C. A.
Stewart
, and
B.
Terry
, “
Power spectrum analyses of nuclear decay rates
,”
Astropart. Phys.
34
,
173
-
178
(
2010
).
4.
D. E.
Alburger
,
G.
Harbottle
, and
E. F.
Norton
, “
Half-life of 32Si
,”
Earth Planet. Sci. Lett.
78
,
168
-
176
(
1986
).
5.
H.
Siegert
,
H.
Schrader
, and
U.
Schötzig
, “
Half-life measurements of europium radionuclides and the long-term stability of detectors
,”
Appl. Radiat. Isot.
49
,
1397
-
1401
(
1998
).
6.
E. D.
Falkenberg
, “
Radioactive decay caused by neutrinos?
,”
Apeiron
8
,
32
-
45
(
2001
).
7.
P. A.
Sturrock
,
L.
Bertello
,
E.
Fischbach
,
D.
Javorsek
II
,
J. H.
Jenkins
,
A.
Kosovichev
, and
A. G.
Parkhomov
, “
An analysis of apparent r-mode oscillations in solar activity, the solar diameter, the solar neutrino flux, and nuclear decay rates, with implications concerning the Suns internal structure and rotation, and neutrino processes
,”
Astropart. Phys.
42
,
62
-
69
(
2013
).
8.
A. G.
Parkhomov
, “
Deviations from beta radioactivity exponential drop
,”
J. Mod. Phys.
2
,
1310
-
1317
(
2011
).
9.
P. A.
Sturrock
,
A. G.
Parkhomov
,
E.
Fischbach
, and
J. H.
Jenkins
, “
Power spectrum analysis of LMSU (Lomonosov Moscow State University) nuclear decay-rate data: Further indication of r-mode oscillations in an inner solar tachocline
,”
Astropart. Phys.
35
,
755
-
758
(
2012
).
10.
J. H.
Jenkins
,
K. R.
Herminghuysen
,
T. E.
Blue
,
E.
Fischbach
,
D.
Javorsek
II
,
A. C.
Kauffman
,
D. W.
Mundy
,
P. A.
Sturrock
, and
J. W.
Talnagi
, “
Additional experimental evidence for a solar influence on nuclear decay rates
,”
Astropart. Phys.
37
,
81
-
88
(
2012
).
11.
P. A.
Sturrock
,
E.
Fischbach
, and
J.
Jenkins
, “
Analysis of beta-decay rates for Ag108, Ba133, Eu152, Eu154, Kr85, Ra226, AND Sr90, Measured at the Physikalisch-Technische Bundesanstalt from 1990 to 1996
,”
Astrophys. J.
794
,
42
(
2014
).
12.
P. A.
Sturrock
,
E.
Fischbach
,
D.
Javorsek
II
,
J. H.
Jenkins
,
R. H.
Lee
,
J.
Nistor
, and
J. D.
Scargle
, “
Comparative study of beta-decay data for eight nuclides measured at the Physikalisch-Technische Bundesanstalt
,”
Astropart. Phys.
59
,
47
-
58
(
2014
).
13.
P. A.
Sturrock
,
J. B.
Buncher
,
E.
Fischbach
,
J. T.
Gruenwald
,
D.
Javorsek
II
,
J. H.
Jenkins
,
R. H.
Lee
,
J. J.
Mattes
, and
J. R.
Newport
, “
Power spectrum analysis of BNL decay rate data
,”
Astropart. Phys.
34
,
121
-
127
(
2010
).
14.
P. A.
Sturrock
,
G.
Steinitz
,
E.
Fischbach
,
D.
Javorsek
II
, and
J. H.
Jenkins
, “
Analysis of gamma radiation from a radon source: Indications of a solar influence
,”
Astropart. Phys.
36
,
18
-
25
(
2012
).
15.
T. M.
Semkow
,
D. K.
Haines
,
S. E.
Beach
,
B. J.
Kilpatrick
,
A. J.
Khan
, and
K.
OBrien
, “
Oscillations in radioactive exponential decay
,”
Phys. Lett. B
675
,
415
-
419
(
2009
).
16.
J. H.
Jenkins
,
D. W.
Mundy
, and
E.
Fischbach
, “
Analysis of environmental influences in nuclear half-life measurements exhibiting time-dependent decay rates
,”
Nucl. Instrum. Methods Phys. Res., Sect. A
620
,
332
-
342
(
2010
).
17.
P. S.
Cooper
, “
Searching for modifications to the exponential radioactive decay law with the Cassini spacecraft
,”
Astropart. Phys.
31
,
267
-
269
(
2009
).
18.
E. B.
Norman
,
E.
Browne
,
H. A.
Shugart
,
T. H.
Joshi
, and
R. B.
Firestone
, “
Evidence against correlations between nuclear decay rates and Earth-Sun distance
,”
Astropart. Phys.
31
,
135
-
137
(
2009
).
19.
D.
OKeefe
,
B. L.
Morreale
,
R. H.
Lee
,
J. B.
Buncher
,
J. H.
Jenkins
,
E.
Fischbach
,
T.
Gruenwald
,
D.
Javorsek
II
, and
P. A.
Sturrock
, “
Spectral content of 22Na/44Ti decay data: Implications for a solar influence
,”
Astrophys. Space Sci.
344
,
297
-
303
(
2013
).
20.
K.
Kossert
and
O. J.
Nähle
, “
Disproof of solar influence on the decay rates of 90Sr/90Y
,”
Astropart. Phys.
69
,
18
-
23
(
2015
).
21.
M. M. M.
Meier
and
R.
Wieler
, “
No evidence for a decrease of nuclear decay rates with increasing heliocentric distance based on radiochronology of meteorites
,”
Astropart. Phys.
55
,
63
-
75
(
2014
).
22.
E. B.
Norman
, “
Additional experimental evidence against a solar influence on nuclear decay rates
,” e-print arXiv:1208.4357 (
2012
).
23.
E.
Fischbach
,
T.
Gruenwald
,
D.
Javorsek
,
J. H.
Jenkins
,
R. H.
Lee
, and
P. A.
Sturrock
, “
Concerning the Phase of the Time-Variation in the 36Cl Decay Rate
,” e-print arXiv:1210.3334 (
2012
).
24.
P. A.
Sturrock
,
J. B.
Buncher
,
E.
Fischbach
,
D.
Javorsek
ii
,
J. H.
Jenkins
, and
J. J.
Mattes
, “
Concerning the phases of the annual variations of nuclear decay rates
,”
Astrophys. J.
737
,
65
(
2011
).
25.
L.
Katz
and
A. S.
Penfold
, “
Range-energy relations for electrons and the determination of beta-ray end-point energies by absorption
,”
Rev. Mod. Phys.
24
,
28
-
41
(
1952
).
26.
D. W.
Allan
,
N.
Ashby
, and
C. C.
Hodge
,
The Science of Timekeeping
,
Application Note
Vol.
1298
(
Hewlett Packard
,
1997
), pp.
1
-
88
.
You do not currently have access to this content.