Muon Lifetime
Alden Deran
Detectors A and B Calibration
160
140
120
Counts per second
100
80
Series1
Series2
Series3
60
Series4
40
20
0
0
-20
0.1
0.2
0.3
0.4
0.5
Voltage (volts)
0.6
0.7
0.8
0.9
1
Detectors C and D Calibration
70
60
50
Counts per second
40
Series1
Series2
30
Series3
Series4
20
10
0
0
-10
0.2
0.4
0.6
0.8
Voltage (volts)
1
1.2
1.4
Muon Energy Loss in Materials
•
•
•
Typical cosmic ray muons experience energy loss in a
material almost completely due to electronic
stopping power – the ionization of atoms in the
material. 1The remaining (approximately 1%) of the
energy loss is due to Bremsstrahlung radiation,
electron/positron pair production, and photonuclear
interraction.
However, due to the much lower mass of electrons,
they are accelerated much more by atomic nuclei
and lose more energy to Bremsstrahlung radiation
than muons. The amount of energy loss due to
Bremsstrahlung radiation is proportional to 1/m4.
This radiation is the dominant form of energy loss for
electrons, so some materials will stop muons while
having a much smaller effect on electrons.
In this experiment, it is hypothesized that books will
stop muons but allow electrons to reach the
detectors.
DAQ Board Setup
• Gate width set to 10 microseconds, and
changed to 15 microseconds for one
experiment.
• TMC delay set to 48 nanoseconds.
• Different coincidence settings were tried.
Muon Lifetime Experimental Setup
When a muon passes through detector A and then is trapped in the
material between the detectors, it will eventually decay into an
electron, which may be detected in another one of the detectors (or
multiple). The time between these two events will be recorded. If a
muon passes through detector a and then is not trapped, it will pass
through another detector within a nanosecond, and this event will
be ignored.
4
5 Hours Stacked With Books
With Books, stacked, 158 minutes
Without Books, Stacked, 158 minutes
Overnight with Partial Box
Partial Box with 2-Fold Coincidence
Results
Data Set
Time (minutes)
Maximum decays
1
5
3
Lifetime
(microseconds)
Error
Comments
Not enough data, gate width set too small
2
Data file was lost
3
36
6
Still not enough data, though several
decays detected
4
120
27
1.921
.307
5
37
3.145
.608
6
150
2.401
0.228
First successful overnight test
7
100
1.870
0.139
Second successful overnight test – box
configuration.
8
80
2.420
.199
2 fold coincidence
9
155
1.913
.107
2 fold coincidence with partial box
10
30
11
1.853
.384
Without books stacked
11
30
13
1.254
.210
With books box configuration
12
158
30
1.897
.346
With books stacked
13
158
39
1.354
.172
Without books stacked
Additional Error Calculations
• Chi-square test can determine how good the
curve fit is.
• Data must be downloaded from quarknet: In
the data plot, click “analysis directory.” Then,
click “lifetimeOut”. Somehow move the data
to an excel file or write an analysis program to
parse the data file.
Sources
1. Groom, Donald E. Muon Stopping Power and Range Tables 10 MeV to 100 TeV.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBB-45BT4PM6&_user=4428&_coverDate=07%2F31%2F2001&_rdoc=1&_fmt=high&_orig=searc
h&_sort=d&_docanchor=&view=c&_acct=C000059601&_version=1&_urlVersion=
0&_userid=4428&md5=3d7e89088f9c3ffdbe1a22f4459f1f7e