54. Recoil Energy (keV)
0 10 20 30 40 50 60 70 80
FIG. 2. The ratio of photon equivalent
~ ~ ~ ~
ionization
ionization energy to
Energy (keV)
recoil energy for nuclear recoils, given as a function of recoil en-
ダークマター探索の歴史
80 ergy. Also shown are measurements from Refs. [4] and [8], an
音になったエネルギー
the calculation of Lindhard, with his parameter k set to 0. 15.
70-
Error bars on our data points are statistical only; systematic er-
60 -.
~
~
~
~
t ~
~
~
~ • CDMS 実験の最初のアイディアは1990
rors are discussed in the text.
without 1992 年には試作品完成
C
50 C .' 年. collimation outside our cryostat and beneath 28
P ' ' ~
l g'
cmof Pb to give similar rates of photons and neu t rons
~ ~
40 ~
g
'1g
~ f o t
LLI
~
. throroughout the detector. The neutrons are clearly dis-
30-
~:
p,
''
~
• 思ったほどうまくいかない時期が長く続
tinguished in Fig. 1(b) as a second line with a greater
slope, i.e. , less ionization per unit phonon energy, than the
~
'a~.
~
4 '
20-
~
~ ~
Q
いて実験が始まったのは2000年ごろ
p otons. Their energy spectrum roughly agrees with a
10- very simple Monte Carlo estimate. (Note that a I MeV
~ V
neutron can deposit at most 53 keV in germanium. )
0 The fractions of the total recoil energy that appear as
0 10 20 30 40 50 60 70 60
ionization and as phonons can be obtained from the data
粒子があたって
Ionization Energy (keV)
as follows. Energetic electrons and holes created in the
FIG. 1. Phonon an ionization equivalent energies measure d initial interaction eventually relax to the band edges via
e イオンとなったエネルギー
for (a) 59.5 eV photons and Compton scatters of b ac k groun d
h
photon s, (b ) The same measurement as (a) with the addition
s. T p onon emission. These N charge pairs carr NE f
p
of neutrons and photons from a Cf source. e original recoil energy Eg, where Es, z is the band-gap
energy. The remaining energy appears as phonons, ex-
cept in the case of nuclear recoils, which may lose a small
photons: The photon peak is at 59.5 keV in both the ion- raction of their energy to the formation of crystal de-
ization and phonon measurements. In this convention ects. As the charge carriers are collected they emit the
photon and charged particle events lie along th 1' f energy they acquire from the drift field as phonons. In
e ual p h onon and ionization energies (for these interac-
equa separate tests [6] we have concluded that when the elec-
tions the partitioning into phonons and ionization is ap- trons reach the implanted regions in this (p+- - +) de-
proximately independent of the incident energy. ) A num- vice the relax to the Fermi level and release their band-
ey
ber of events can in fact be seen along this line. From gap energy as phonons. The measured phonon ener non energy,
measurements with a NaI counter, we ascribe most of f
—
then, isE=~E Ir + eNV, where f describes any energy lost
t ese background events to Compton scattered 1.45 MeV
K which is present in the walls of the room.
f
to defects (r = for no loss), e is the magnitude of the
=1
electron's charge, and V is the charge collection potential
y rays from
The rms
12年7月4日水曜日 resolution of the 59.5 keV pea k is t
e p typically l
ll =0.5 V for this data set). In Ref. [61 we describe the
55. Recoil Energy (keV)
0 10 20 30 40 50 60 70 80
FIG. 2. The ratio of photon equivalent
~ ~ ~ ~
ionization
ionization energy to
Energy (keV)
recoil energy for nuclear recoils, given as a function of recoil en-
ダークマター探索の歴史
80 ergy. Also shown are measurements from Refs. [4] and [8], an
音になったエネルギー
the calculation of Lindhard, with his parameter k set to 0. 15.
70-
Error bars on our data points are statistical only; systematic er-
60 -.
~
~
~
~
t ~
~
~
~ • CDMS 実験の最初のアイディアは1990
rors are discussed in the text.
without 1992 年には試作品完成
C
50 C .' 年. collimation outside our cryostat and beneath 28
P ' ' ~
l g'
cmof Pb to give similar rates of photons and neu t rons
~ ~
40 ~
g
'1g
~ f o t
LLI
~
. throroughout the detector. The neutrons are clearly dis-
30-
~:
p,
''
~
• 思ったほどうまくいかない時期が長く続
tinguished in Fig. 1(b) as a second line with a greater
slope, i.e. , less ionization per unit phonon energy, than the
ものすごく興奮した
~
'a~.
~
4 '
20-
~
~ ~
Q
いて実験が始まったのは2000年ごろ
p otons. Their energy spectrum roughly agrees with a
10- very simple Monte Carlo estimate. (Note that a I MeV
~ V
neutron can deposit at most 53 keV in germanium. )
0 The fractions of the total recoil energy that appear as
0 10 20 30 40 50 60 70 60
ionization and as phonons can be obtained from the data
粒子があたって
Ionization Energy (keV)
as follows. Energetic electrons and holes created in the
FIG. 1. Phonon an ionization equivalent energies measure d initial interaction eventually relax to the band edges via
e イオンとなったエネルギー
for (a) 59.5 eV photons and Compton scatters of b ac k groun d
h
photon s, (b ) The same measurement as (a) with the addition
s. T p onon emission. These N charge pairs carr NE f
p
of neutrons and photons from a Cf source. e original recoil energy Eg, where Es, z is the band-gap
energy. The remaining energy appears as phonons, ex-
cept in the case of nuclear recoils, which may lose a small
photons: The photon peak is at 59.5 keV in both the ion- raction of their energy to the formation of crystal de-
ization and phonon measurements. In this convention ects. As the charge carriers are collected they emit the
photon and charged particle events lie along th 1' f energy they acquire from the drift field as phonons. In
e ual p h onon and ionization energies (for these interac-
equa separate tests [6] we have concluded that when the elec-
tions the partitioning into phonons and ionization is ap- trons reach the implanted regions in this (p+- - +) de-
proximately independent of the incident energy. ) A num- vice the relax to the Fermi level and release their band-
ey
ber of events can in fact be seen along this line. From gap energy as phonons. The measured phonon ener non energy,
measurements with a NaI counter, we ascribe most of f
—
then, isE=~E Ir + eNV, where f describes any energy lost
t ese background events to Compton scattered 1.45 MeV
K which is present in the walls of the room.
f
to defects (r = for no loss), e is the magnitude of the
=1
electron's charge, and V is the charge collection potential
y rays from
The rms
12年7月4日水曜日 resolution of the 59.5 keV pea k is t
e p typically l
ll =0.5 V for this data set). In Ref. [61 we describe the
56. Recoil Energy (keV)
0 10 20 30 40 50 60 70 80
FIG. 2. The ratio of photon equivalent
~ ~ ~ ~
ionization
ionization energy to
Energy (keV)
recoil energy for nuclear recoils, given as a function of recoil en-
ダークマター探索の歴史
80 ergy. Also shown are measurements from Refs. [4] and [8], an
音になったエネルギー
the calculation of Lindhard, with his parameter k set to 0. 15.
70-
Error bars on our data points are statistical only; systematic er-
60 -.
~
~
~
~
t ~
~
~
~ • CDMS 実験の最初のアイディアは1990
rors are discussed in the text.
without 1992 年には試作品完成
C
50 C .' 年. collimation outside our cryostat and beneath 28
P ' ' ~
l g'
cmof Pb to give similar rates of photons and neu t rons
~ ~
40 ~
g
'1g
~ f o t
LLI
~
. throroughout the detector. The neutrons are clearly dis-
これはダークマターも大変だなあと •
30- p, 思ったほどうまくいかない時期が長く続
tinguished in Fig. 1(b) as a second line with a greater
~: '' 'a~.
~
slope, i.e. , less ionization per unit phonon energy, than the
ものすごく興奮した
~ ~
4 '
20-
~
思ってコライダー実験の ~ ~
Q
いて実験が始まったのは2000年ごろ
p otons. Their energy spectrum roughly agrees with a
10- very simple Monte Carlo estimate. (Note that a I MeV
~ V
研究に変わった neutron can deposit at most 53 keV in germanium. )
0 The fractions of the total recoil energy that appear as
0 10 20 30 40 50 60 70 60
ionization and as phonons can be obtained from the data
粒子があたって
Ionization Energy (keV)
as follows. Energetic electrons and holes created in the
FIG. 1. Phonon an ionization equivalent energies measure d initial interaction eventually relax to the band edges via
e イオンとなったエネルギー
for (a) 59.5 eV photons and Compton scatters of b ac k groun d
h
photon s, (b ) The same measurement as (a) with the addition
s. T p onon emission. These N charge pairs carr NE f
p
of neutrons and photons from a Cf source. e original recoil energy Eg, where Es, z is the band-gap
energy. The remaining energy appears as phonons, ex-
cept in the case of nuclear recoils, which may lose a small
photons: The photon peak is at 59.5 keV in both the ion- raction of their energy to the formation of crystal de-
ization and phonon measurements. In this convention ects. As the charge carriers are collected they emit the
photon and charged particle events lie along th 1' f energy they acquire from the drift field as phonons. In
e ual p h onon and ionization energies (for these interac-
equa separate tests [6] we have concluded that when the elec-
tions the partitioning into phonons and ionization is ap- trons reach the implanted regions in this (p+- - +) de-
proximately independent of the incident energy. ) A num- vice the relax to the Fermi level and release their band-
ey
ber of events can in fact be seen along this line. From gap energy as phonons. The measured phonon ener non energy,
measurements with a NaI counter, we ascribe most of f
—
then, isE=~E Ir + eNV, where f describes any energy lost
t ese background events to Compton scattered 1.45 MeV
K which is present in the walls of the room.
f
to defects (r = for no loss), e is the magnitude of the
=1
electron's charge, and V is the charge collection potential
y rays from
The rms
12年7月4日水曜日 resolution of the 59.5 keV pea k is t
e p typically l
ll =0.5 V for this data set). In Ref. [61 we describe the