KIT – University of the State of Baden-Württemberg and National Research Center of the Helmholtz Association KIT Center Elementary Particle and Astroparticle Physics (KCETA) Institute for Nuclear Physics (IKP) www.kit.edu The KATRIN experiment Hardware commissioning SDS measurements Transmission measurements Background measurements Commissioning of the KATRIN spectrometer and detector section Nancy Wandkowsky for the KATRIN collaboration 561. WEH-Seminar „Massive Neutrinos“, Bad Honnef
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KIT – University of the State of Baden-Württemberg and
National Research Center of the Helmholtz Association
KIT Center Elementary Particle and Astroparticle Physics (KCETA)
Institute for Nuclear Physics (IKP)
www.kit.edu
The KATRIN experiment
Hardware commissioning
SDS measurements
Transmission measurements
Background measurements
Commissioning of the KATRIN spectrometer and detector section Nancy Wandkowsky for the KATRIN collaboration
561. WEH-Seminar „Massive Neutrinos“, Bad Honnef
2 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
The KATRIN experiment
3
The KATRIN experiment
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Direct determination of m(𝝂 e)
β-decay: (A,Z) → (A,Z+1) + e- + ν 𝑒
Electron energy spectrum:
Expected count rate: 10-2 cps
4
The KATRIN experiment
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
source transport spectrometer detector
• sensitivity:
upper limit: 200 meV (90% CL)
discovery: 350 meV (5σ)
• predecessor experiments (Mainz, Troitsk): m(ν e) < 2.1 eV
KArlsruhe TRItium Neutrino experiment (KATRIN)
5 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
low endpoint β source
high count rate
high energy resolution
low background (<10-2 cps)
key requirements:
The KATRIN experiment
KArlsruhe TRItium Neutrino experiment (KATRIN)
source transport spectrometer detector
6 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
low endpoint β source
high count rate
high energy resolution
low background (<10-2 cps)
key requirements:
The KATRIN experiment
KArlsruhe TRItium Neutrino experiment (KATRIN)
source transport spectrometer detector
E0 = 18.6 keV
7 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
low endpoint β source
high count rate
high energy resolution
low background (<10-2 cps)
key requirements:
The KATRIN experiment
KArlsruhe TRItium Neutrino experiment (KATRIN)
source transport spectrometer detector
8
The KATRIN experiment
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
distance to analyzing plane (m) -10 0 10
pote
ntial (k
V)
-20
-20 -30 -40
-10
0
source transport spectrometer detector
9
The KATRIN experiment
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
distance to analyzing plane (m)
B-f
ield
(T
) pote
ntial (k
V)
1
10-1
10-2
0
-10
-20
-10 0 10 -20 -30 -40
Bmin
Bmax
𝒑
𝑩
𝜽
𝒑
𝑩
MAC
E filter
Magnetic adiabatic collimation
& electrostatic filter
𝜇 =𝐸⊥𝐵
= 𝑐𝑜𝑛𝑠𝑡. orb. magn. moment
10
The KATRIN experiment
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
distance to analyzing plane (m)
B-f
ield
(T
) pote
ntial (k
V)
1
10-1
10-2
0
-10
-20
-10 0 10 -20 -30 -40
Bmin
Bmax
E filter
Magnetic adiabatic collimation
& electrostatic filter
high acceptance angle
energy resolution:
Δ𝐸 = 𝐸0𝐵𝑚𝑖𝑛
𝐵𝑚𝑎𝑥= 1 eV
11 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
low endpoint β source
high count rate
high energy resolution
low background (<10-2 cps)
key requirements:
The KATRIN experiment
KArlsruhe TRItium Neutrino experiment (KATRIN)
source transport spectrometer detector
12
low endpoint β source
high count rate
high energy resolution
low background (<10-2 cps)
key requirements:
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
The KATRIN experiment
KArlsruhe TRItium Neutrino experiment (KATRIN)
13 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware commissioning
14
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
NEG pumps
and
baffle system
inner electrode system
detector electron-gun
SDS Commissioning in 2013
SDS = spectrometer and detector section
Air coil system
15 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware Commissioning
Air coil system
without any air coil system (solenoids only)
distorted flux tube due to earth magnetic field
central field too weak
B = 6 T B = 1·10-4 T
flux tube transporting signal electrons
16 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware Commissioning
Air coil system
with earth magnetic field compensation system (EMCS)
flux tube symmetric around spectrometer axis
central field too weak (desired value: 3·10-4 T)
B = 6 T
EMCS
B = 1·10-4 T
17 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware Commissioning
Air coil system
with EMCS and low field correction system (LFCS)
central field at desired value: 3·10-4 T
full transmission
B = 6 T
EMCS LFCS
B = 3·10-4 T
18 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware Commissioning
Air coil system
with EMCS and low field correction system (LFCS)
central field at desired value: 3·10-4 T
full transmission & background suppression (factor 105)
B = 6 T
e
B = 3·10-4 T
EMCS LFCS
19
Ø = 12.6 m
LFCS EMCS
large
Helmholtz
coil system
main
spectrometer
vessel
20
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
electron energy analysis background suppression
U0
U1
U2
• single layer: factor ~10
• double layer: factor 100
• smooth electric potential
• maximal potential in center (-18.6 kV)
Inner electrode & high voltage system
250 modules, > 24000 wires
21
Inner Electrode System
Jan. 31, 2012
22
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
NEG pump & baffle system
NEG: UHV Baffle: radon cold trap
• 6 turbo-molecular pumps: 104 ℓ/s (H2)
• 3 NEG-pumps (3000 m strips): ~106 ℓ/s (H2)
• 3 LN2-cooled baffles: ~170 000 ℓ/s (Rn)
J. Wolf – Poster 23
23
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Closing the vessel
after completion of
installations within vessel
24
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Ultra-high vacuum (UHV)
• goal: 10-11 mbar in volume of 1240 m3
• spectrometer bake-out:
• water removal from surface
• activation of chemical getter pump
• achieved: 10-10 mbar
T
p
25 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Hardware commissioning
J. Wolf
0
50
100
150
200
250
300
350
insulator
6
-40 -30 -20 -10 0 +10
distance from analysing plane [m]
po
ten
tia
l [k
V]
-20
-10
0
tritium source
1
10-1
10-2
spectrometer
Bmin
Bmax
magnetic field & electrostatic potential
B-f
ield
[T
]
T. Thümmler - KATRIN Experiment
fix point
Spectrometer bake-out: vessel expansion
tem
pera
ture
26
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Electron gun
• Quasi-monoenergetic
• Angular selective
M. Zacher – Poster 24
27
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Electron gun
• Quasi-monoenergetic
• Angular selective
• Diagnostic tool
• Study of signal electron transport
28
Hardware commissioning
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
• May 16, 2013: SDS connection established
• May 28, 2013: opening gate valve
Integration of detector and spectrometer
148 pixel Si-PIN diode
29 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Total background in ROI: <4.6 ± 0.2 mcps (goal: 1 mcps)
Peaks are measurement artefact.
ROI
Energy (keV)
Rate
(1/s
ec/k
eV
)
Detector performance
Hardware commissioning
30
Spectrometer Detector
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
detector integration requires valve inside
magnet bore: beam-line valve
deformation of O-Ring during baking
disabled the valve’s basic function
challenge to attach detector without
venting / getter contamination
X-rays visual
Hardware commissioning
31 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
XENON 1t
gas purification system (SAES)
144 bottles Argon N6.0
O-ring exchanged in Ar atmosphere
beam-line valve now leak tight
detector section attached
replacing the O-ring requires work
under inert gas atmosphere (Ar)
NEG pump requires Ar of quality
N9.0 to prevent contamination
Hardware commissioning
32 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
SDS measurements
33 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Main goals:
Test of Hardware and Slow Control components
Understanding of transmission properties
Measurement and Understanding of background
Verification of simulations software and models
Main Spectrometer
Electron
Gun
Detector
Section
Main Spectrometer
Electron
Gun
Detector
Section
Spectrometer-Detector-Section commissioning
34
Det
First „light“
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
• May 31, 2013
• map field emission from
electrode onto detector
• misalignment: tilted detector
chamber
• confirmed by simulations
Asymmetric magnetic field
35
First „light“
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
• May 31, 2013
• map field emission from
electrode onto detector
• misalignment: tilted detector
chamber
• confirmed by simulations
• shadow: flapper valve
Asymmetric magnetic field
36 N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
SDS measurements
transmission of ß-electrons:
magnetic guiding &
electrostatic retardation
B [T]
e
e e
q [°]
background:
spectrometer acts as
a magnetic bottle,
long storage (h)
37
Transmission measurements
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
e-gun energy distribution (schematically)
Study of signal electron transport
starting energy
|U2|<|U1|
38
Transmission measurements
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Study of signal electron transport
39
Transmission measurements
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
Study of signal electron transport
• Transmission functions measured at various retarding potentials [0, -18.6 kV]
• … and radial positions (e-gun manipulator used to pinpoint individual pixels)
• width of transmission function dominated by systematic effects of the electron
gun (energy spread and angular spread) → spectrometer works as expected
V. Hannen – Session 15
40
Background measurements
N. Wandkowsky, Commissioning of the KATRIN spectrometer and detector section, Bad Honnef, 2014
781.9 ± 2.7 mcps
First look at background @ full high voltage setup