θ - IN2P3

CRES — A NEW METHOD TOWARDS
MEASURING THE 𝜈-MASS
SEBASTIAN BÖSER
7 TH J U N E 2 0 1 6 | G D R N E U T R I N O 2 0 1 6 | G R E N O B L E
MEASURING 𝜈-MASS
Project8 — 2
T R I T I U M B E TA - D E C AY
3H
→ 3He+ + e- + 𝜈̅e
• Sum of masses and kinetic energy must add
up to mass of initial nucleus
Project8 — 3
T R I T I U M B E TA - S P E C T R U M
q
dN
⇠ F (Z, E)pe (E + me ) (E
dE
E0 ) 2
m2 )
Project8 — 4
T R I T I U M B E TA - S P E C T R U M
✓
dN
⇠ F (Z, E)pe (E + me ) (E
dE
E0 )
2
Endpoint of spectrum changes with 𝜈-mass
→ direct measurement of mass
(independent of “nature” of mass)
1 2
m )
2
◆
Project8 — 5
T R I T I U M B E TA - S P E C T R U M
• Fraction of e− in ROI
• 10 eV: 2×10−10
•
1 eV: 2×10−13
• Requirements
• high count rate
• high resolution
Endpoint of spectrum changes with 𝜈-mass
→ direct measurement of mass
(independent of nature of mass)
Project8 — 6
S TAT E O F T H E A R T — K AT R I N
m
e
t
s
y
s
l
i
o
c
r
i
a
e
m
u
l
o
v
e
g
r
a
l
N
I
R
T
A
K
e
h
t
f
o
n
g
i
s
e
d
c
ti
Key component: MAC-E filter
• align e- momentum p? ! pk
Project8 — 7
K
AT
R
I
N
Karlsruhe Trititum Neutrino Experiment
Sensitivity goal
• mβ < 200meV
Limited by
• size of spectrometer
• systematic effects
➔ need a new and
complementary approach
Inverted hierarchy
Normal hierarchy
Project8 — 8
C Y C L O T R O N R A D I AT I O N
Cyclotron radiation
1 eB?
fc =
2⇡ me
relativistic correction
f =
fc
1
eB?
=
2⇡ me + Ekin
“Never measure anything but frequency” - A. L. Schawlow
Project8 — 9
RESOLUTION
Energy resolution
f ⋅ ΔE/E ~ Δf
• ΔE/E ~ 1eV / 511 keV = 2ppm
→ easy!
Frequency resolution
Δf ~ 1/Δt
• Δt = 20μs ~ 1400m @ 18keV
→ hard!
A. L. Schawlow
Project8 — 10
Idea
• fill volume with 3H gas
• add magnetic field
• decay electrons spiral
around field lines
• add antennas to detect
cyclotron radiation
B. Monreal and J. Formaggio, Phys. Rev D80:051301
Project8 — 11
FREQUENCY SCALE
magnetic field of 1T → cyclotron frequency in K-Band
83mKr
provides electrons close to tritium endpoint
Project8 — 12
R A D I AT E D P O W E R
Larmor formula
1 2 q4 B 2
P ( , ✓) =
(
4⇡"0 3 m2e
2
Emitted power
• 1.1 fW for 18 keV e- at 90º
• 1.7 fW for 30.4 keV e- at 90º
2
1) sin ✓
pe
θ → pitch angle
B-field
→ Low-noise cryogenic RF-system needed!
Project8 — 13
PROJECT8 PROTOTYPE
Signal
Project8 — 14
WAV E G U I D E C E L L
Project8 — 15
S I G N A L A M P L I F C AT I O N A N D N O I S E
Noise temperature: Teff = 150K
fine Swedish
amplifier
• Primary background
→ thermal noise from waveguide and amplifiersProject8 —
16
R E C E I V E R S TA G E
• Double-stage down-mixing
• Digitizer: 8-bit, 500Ms/s, 125MHz bandwidth
→ untriggered
Project8 — 17
MAGNETIC BOTTLE
Harmonic
e-
trap →
f =
fc
1
eB
=
2⇡ me + Ekin
✓
2
cot ✓
1+
2
◆
5mT
Different
pitch angles
Magentic
bottle coil
Effect of trap on measured frequency easily calculable!
Project8 — 18
EXPECTED SIGNAL
Spectrogram
• time slices
→ consecutive
power spectrum
Signal
• narrow-band → horizontal line
• energy loss by radiation
→ line is tilted
Project8 — 19
ACTUAL SPECTROGRAM
Data Taking on 06/06/2014 immediately shows trapped electrons
PhysRevLett.114.162501 (2015)
First detection of single-electron cyclotron radiation!
Project8 — 20
S P E C T R O G R A M I N F O R M AT I O N
Project8 — 21
ENERGY SPECTRUM
Initial frequency determines initial energy
Project8 — 22
FIRST ENERGY SPECTRUM
Both 83mKr lines
→ clearly seen
Resolution
• FWHM: 140 eV
Phys. Rev. Lett. 114, 162501 (2015)
Project8 — 23
IMPROVED TRAP
Shallower Harmonic trap
• better field uniformity
• smaller acceptance
→ lower rate &
better resolution
Bathtub trap
• two coils at end of cell
• better uniformity
• larger trap size
→ larger rate &
better resolution
Project8 — 24
C R E S — C Y C L O T R O N R A D I AT I O N EMISSON SPECTROSCOPY
Hardware
improvements
• better field
uniformity
• reduced
noise level
• better
temperature
stability
Project8 — 25
POTENTIAL 𝜈-MASS REACH
σ(B) ~ 0.1ppm, 1 year of data
per cm3
per cm3
per cm3
per cm3
Sensitivity limited by gas density!
Project8 — 26
POTENTIAL 𝜈-MASS REACH
current cell
volume
current limit
per cm3
per cm3
inverted hierarchy bound
per cm3
Inverted hierarchy limit in reach with atomic tritium!
Project8 — 27
P R O Project
J E C T 88
C O L Collaboration
L A B O R AT I O N
T. Thümmler
T. Thuemmler
Karlsruhe Institute
of Technology
Karlsruhe Institute of Technology
S. Böser, C. Claessens*
S. Boser, C. Claessens*
Johannes Gutenberg-Universität,
Mainz
Johannes Gutenberg Universiẗat, Mainz
K. Kazkaz
K. Kazkaz
Lawrence Livermore
National
Laboratory
Lawrence Livermore
National
Laboratory
J. Formaggio,
N. Oblath, E. Zayas*
J. Formaggio, N. Oblath, E. Zayas*
Massachusetts
InstituteInstitute
of Technology
Massachusetts
of Technology
M. Guigue,
A. M. Jones,
J. Tedeschi,
B. VanDevender
M. Guigue,
A. M. Jones,
J. Tedeschi,
B. VanDevender
Pacific Northwest
NationalNational
Lab
Pacific Northwest
* indicates graduate student
* indicates graduate student
Lab
S. Doelman,
J. Weintroub,
A. Young
S. Doelman,
J. Weintroub,
A. Young
Astrophysical
Observatory
Smithsonian Smithsonian
Astrophysical
Observatory
*, B. Monreal
L. de Viveros,
B. LaRoque*,
B. Monreal
L. de Viveros,
B. LaRoque
K. Heeger,
L. Saldana*,
P. Slocum
K. Heeger,
L. Saldana*,
P. Slocum
University of California, Santa Barbara
University of California, Santa Barbara
Yale University
Yale University
P. Doe, A.A. Esfahani, M. Fertl, E. Machado, R.G.H. Robertson, L. Rosenberg, G. Rybka
P. Doe, A.University
Ashtari
Esfahani*, M. Fertl, E. Machado*, R.G.H. Robertson,
of Washington, Center for Experimental Nuclear Physics and Astrophysics
L. Rosenberg, G. Rybka
University of Washington, Center for Experimental Nuclear Physics and Astrophysics
Project8 — 28
A PHASED APPROACH
Pha se Tim el in e So u rce
I
2 0 1 0 -2 0 16
83mK r
R & D M i le s to n e s
S c i e n ce G o al s
co n v e r s i o n e le ct r o n
dete ct io n
sp e ctr um of
pro of of co nce p t
II
III
IV
2 0 1 5 -2 0 1 7
2 0 16 -2 0 2 0
2017…
T2
T2
T
D
E
T
E
L
8 3 mO
KM
r P
C
s i ng le e le ct r o n
Ku r i e p lot
s y s t e m at i c s t u d i e s
F i n a l - s t at e s p e c t r u m t e s t
3H
- 3H e m a s s d iff e re n ce
m 𝜈 < 1 0 - 1 0 0 e V/c 2
h i g h - r at e s e n s i t i v i t y
B-Field mapp ing
m𝜈
< 2 e V/c 2
at o m i c t r i t i u m
m𝜈
< 4 0 m e V/c 2
so urce
m easure m𝜈 or deter mine
no r m al h i e r ar c hy
Project8 — 29
PHASE-II : TRITIUM
Improved insert installed
• first 83mKr data available → very promising
• T2 - system ready to be installed
Project8 — 30
PHASE III - LARGE VOLUME
Example antenna configuration and vertex resolution being modeled
• Larger bore ~1T magnet → exists
• Phased array antenna configurations
→ under study
Project8 — 31
M O L E C U L A R T R I T I U M L I M I TAT I O N S
(3HeT)+
(3HeH)+
Molecular excitations
in daughter molecule
• blur tritium endpoint
→ fundamental limit
to measurement
of 𝜈-mass
Need atomic tritium for
ultimate experiment!
Advances in High Energy Physics 2013 (2013) 39
Project8 — 32
P H A S E I V : AT O M I C T R I T I U M
Studying Ioffe-Pritchard trap
• couple to nuclear
magnetic moment
E=
~
µ
~ ·B
• similar to BEC and anti-
hydrogen traps (ALPHA)
Challenges
• cool atomic tritium
to sub-Kelvin
• need high T/T2 purity
Alexi Radovinsky, MIT Magnet Lab
Project8 — 33
SUMMARY
Project 8:
• new technology: CRES - Cyclotron Radiation
Emission Spectroscopy
Next step
• measure full tritium spectrum
Longer-term future
• large scale setup limited by tritium density and
molecular excitations
→ phased antenna array
→ atomic tritium source
Project8 — 34
BACKUP
A D I A B AT I C I N V A R I A N C E
Adiabatic invariance
• Φ = B⋅A = B π rcycl2
≃ p⊥2 / (q⋅B) = const
Slowly changing B
• p⊥ → p||
Project8 — 36
M A C - E F I LT E R
Magnetic Adiabatic Collimation with Electrostatic Filter
Combination of
• Adiabatically
changing B-field
→ convert E⊥ to E||
• E-field to
filter by energy
Resolution
• ratio of Bs / BA
→ limited by size
Project8 — 37
D I S E N TA N G L I N G E N E R G Y A N D A N G L E
Electron oscillates in trap
• axial mode (in harmonic trap)
✓
◆
a
4 sin ✓
!a / v
+
sin ✓ me cos2 ✓
• sidebands to
cyclotron peak
• distance depends
on pitch angle θ
noise level
1
main
frequency
sidebands
Project8 — 38
frequency [MHz]
S I D E B A N D O B S E R V AT I O N
time [s]
Project8 — 39
THREE DEGREES OF FREEDOM
Project8 — 40