Search forLight-Dark Matter with
NEWS-G and MIGDAL
Patrick Knights
University of Birmingham

Kamioka Seminar
14th November 2023
Sogoto 1F Kajita Hall
Birmingham
GaseousDetectors
Laboratory

p.r.knights@bham.ac.uk

The Dark Matter Puzzle
One of the greatest mysteries of modern physics:‘What makes up 84% of matter?’➡Leading explanation is Dark Matter
Astron.Astrophys. 641 (2020) A6

Cosmic Microwave Background
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

2

The Dark Matter Puzzle
One of the greatest mysteries of modern physics:‘What makes up 84% of matter?’➡Leading explanation is Dark Matter
Astron.Astrophys. 641 (2020) A6

Cosmic Microwave Background

Astrophys.J.Lett. 648 (2006) L109-L113

Gravitational lensing
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

2

The Dark Matter Puzzle
One of the greatest mysteries of modern physics:‘What makes up 84% of matter?’➡Leading explanation is Dark Matter
Astron.Astrophys. 641 (2020) A6

Cosmic Microwave Background

Astrophys.J.Lett. 648 (2006) L109-L113

Gravitational lensing
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

Phil.Trans.Roy.Soc.Lond.A 320 (1986) 1556, 447-464

Galactic rotation curves
14/11/2023

2

The Dark Matter Puzzle
One of the greatest mysteries of modern physics:‘What makes up 84% of matter?’➡Leading explanation is Dark Matter
Astron.Astrophys. 641 (2020) A6

Cosmic Microwave Background

Astrophys.J.Lett. 648 (2006) L109-L113

Gravitational lensing
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

DM properties:‘Weakly’ interacting
Non-baryonic
Electrically neutral
Non-relativistic
Long-lived
No known particle
solves the puzzle!
Phil.Trans.Roy.Soc.Lond.A 320 (1986) 1556, 447-464

Galactic rotation curves
14/11/2023

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Dark Matter Detection

Particle candidate landscape

Rept.Prog.Phys. 85 (2022) 5, 056201

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Dark Matter Detection

Particle candidate landscape

Adapted from https://astrobackyard.com/cygnus-constellation/

Rept.Prog.Phys. 85 (2022) 5, 056201

Local DM density, ρ~0.3-0.4 GeV cm-3J.Phys. G41 (2014) 063101
JCAP 1008 (2010) 004
7-2-1
Local flux φ~(10 /mχ[GeV]) cm s
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Dark Matter Detection

Particle candidate landscape

Adapted from https://astrobackyard.com/cygnus-constellation/

Rept.Prog.Phys. 85 (2022) 5, 056201

Local DM density, ρ~0.3-0.4 GeV cm-3J.Phys. G41 (2014) 063101
JCAP 1008 (2010) 004
7-2-1
Local flux φ~(10 /mχ[GeV]) cm s
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

3

Landscape of Direct DM Searches
Rept.Prog.Phys. 85 (2022) 5, 056201

World-leading sensitivities from dualphase liquid noble gas experiments
LZ, XENON-1T, PANDA-X…
Lower-masses less well constrained
LZ arXiv:2207.03764

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Landscape of Direct DM Searches
Rept.Prog.Phys. 85 (2022) 5, 056201

World-leading sensitivities from dualphase liquid noble gas experiments
LZ, XENON-1T, PANDA-X…
Lower-masses less well constrained
LZ arXiv:2207.03764

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

4

Landscape of Direct DM Searches
Rept.Prog.Phys. 85 (2022) 5, 056201

Region has attracted theoreticalinterest➡Asymmetric DM➡Dark sectors
Exploring light-DM region with nuclear
recoils requires:➡Low energy threshold➡Low mass nuclei➡Novel approaches

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

LZ arXiv:2207.03764

14/11/2023

4

Exploring Uncharted Territory
Rept.Prog.Phys. 85 (2022) 5, 056201

Light DM searches through→Innovative uses of existing detectors→Novel detector technologies→Future detectors

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

5

Exploring Uncharted Territory
Rept.Prog.Phys. 85 (2022) 5, 056201

Light DM searches through→Innovative uses of existing detectors→Novel detector technologies→Future detectors

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Heavier targets → Lower recoil energy for lighter candidates
Can use other processes to enable searches

maxER [keV]

The Migdal Effect10
1

Target
Xe
Ar
Ne
He
H

10−1
10−2
−3

10

10−1

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar1

10

14/11/2023

102mχ [GeV]7

maxER [keV]

The Migdal EffectHeavier targets → Lower recoil energy for lighter candidates
Can use other processes to enable searches
Migdal effectObserved in other processes but not nuclear scattering
Key to unlocking light DM searches with many current experiments!
e.g. Phys.Rev.Lett. 122 (2019) 13, 131301

Phys.Rev.Lett. 123 (2019) 24, 241803

Phys.Rev.Lett. 130 (2023) 10, 101001

101

Target
Xe
Ar
Ne
He
H

10−1
10−2
−3

10

10−1

1

10

102
mχ [GeV]

nucleuseelectron cloud
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

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The MIGDAL Collaboration

Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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The MIGDAL Collaboration

MIGDAL experimental signature

Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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MIGDAL Detector: Optical TPC
Astropart.Phys. 151 (2023) 102853

JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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MIGDAL Detector: Optical TPC
Astropart.Phys. 151 (2023) 102853

Neutrons from D-D (2.5 MeV)
and D-T (14.7 MeV) generators

JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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MIGDAL Detector: Optical TPC
PMT
3-inch Hamamatsu R11410
light from initial ionisation (S1)and avalanche (S2)Informs absolute z-position

Astropart.Phys. 151 (2023) 102853

Neutrons from D-D (2.5 MeV)
and D-T (14.7 MeV) generators

JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

9

MIGDAL Detector: Optical TPC
PMT
3-inch Hamamatsu R11410
light from initial ionisation (S1)and avalanche (S2)Informs absolute z-position

Astropart.Phys. 151 (2023) 102853

Neutrons from D-D (2.5 MeV)
and D-T (14.7 MeV) generators

GEMs
Electrons amplification in
double glass GEMs

JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

9

MIGDAL Detector: Optical TPC
PMT
3-inch Hamamatsu R11410
light from initial ionisation (S1)and avalanche (S2)Informs absolute z-position

Astropart.Phys. 151 (2023) 102853

Neutrons from D-D (2.5 MeV)
and D-T (14.7 MeV) generators

GEMs
Electrons amplification in
double glass GEMs

ITO (Indium tin oxide) anode
Transparent: light passes
through to camera
Measures amplified charge
Provides 2D charge ‘image’in x—z plane

JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

9

MIGDAL Detector: Optical TPC
PMT
3-inch Hamamatsu R11410
light from initial ionisation (S1)and avalanche (S2)Informs absolute z-position

Astropart.Phys. 151 (2023) 102853

Neutrons from D-D (2.5 MeV)
and D-T (14.7 MeV) generators

GEMs
Electrons amplification in
double glass GEMs
CMOS camera
Hamamatsu ORCA Quest
Records avalanche light
Provides 2D image

ITO (Indium tin oxide) anode
Transparent: light passes
through to camera
Measures amplified charge
Provides 2D charge ‘image’in x—z plane

Combined with ITO for 3D
track reconstruction
JINST 18 (2023) 07, C07013
Astropart.Phys. 151 (2023) 102853

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Light and Charge Read-Out Systems
Photomultiplier

CMOS Camera

Glass Electron Multipliers (GEMs)

Indium Tin Oxide Electrode

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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MIGDAL Installation at NILE, RAL
Installation of detector at NILE (RAL) completed Summer 2023

controlroom

MIGDALexperiment(shielded)

D-D
generator

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminarinterlocked
accessD-T
generator

concreteshielding

14/11/2023

11

MIGDAL Installation at NILE, RAL
Installation of detector at NILE (RAL) completed Summer 2023

controlroom

MIGDALexperiment(shielded)

D-D
generator

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminarinterlocked
accessD-T
generator

concreteshielding

14/11/2023

11

MIGDAL Installation at NILE, RAL

Installation of detector at NILE (RAL) completed Summer 2023
D-D generator run with CF4 from 17th of July to the 3rd of August➡Lower neutron rate than design
Frames taken with 20 ms exposure time➡Longer than planned due to problems with camera firmware
Regular calibration runs (55Fe) to monitor detector gain
➡GEM voltages incremented each day to keep constant gain

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminarinterlocked
accesscontrolroom

MIGDALexperiment(shielded)

D-D
generator

D-T
generator

concreteshielding

14/11/2023

11

First Neutron Data - Example NR Event

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

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First Neutron Data - Migdal-like Event
Data taken with 55Fe and D-D
concurrently
Migdal-like event in camera Analyse event!

More on YOLO: J. Sheuler CPAD2023

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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First Neutron Data - Migdal-like Event
Data taken with 55Fe and D-D
concurrently
Migdal-like event in camera Analyse event!
Identify energy deposits
using machine learning (YOLO)
Overlapping ER and NR
bounding boxes is Migdal
signature

Electron Recoil
Nuclear Recoil

More on YOLO: J. Sheuler CPAD2023

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

13

First Neutron Data - Migdal-like Event
Data taken with 55Fe and D-D
concurrently
Migdal-like event in camera Analyse event!
Identify energy deposits
using machine learning (YOLO)
Overlapping ER and NR
bounding boxes is Migdal
signature
Identify events in ITOMore on YOLO: J. Sheuler CPAD2023

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

13

First Neutron Data - Migdal-like Event
Data taken with 55Fe and D-D
concurrently
Migdal-like event in camera Analyse event!
Identify energy deposits
using machine learning (YOLO)
Overlapping ER and NR
bounding boxes is Migdal
signature
Identify events in ITO
ITO timing shows these arecoincident in the camera
frame (20 ms), but distinct
eventsMore on YOLO: J. Sheuler CPAD2023

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Next Steps
Analysis of first science run ongoing➡50% of data is blinded
Preparing to continue science run currently➡Resolved some small hardware issues with detector
Future plans: Perform measurements in other gases,
e.g. Ar:CF4, Xe:CF4

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

14

Exploring Uncharted Territory
Rept.Prog.Phys. 85 (2022) 5, 056201

Light DM searches through→Innovative uses of existing detectors→Novel detector technologies→Future detectors

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

15

NEWS-G

Light DM searches with a novel gaseous detector, the spherical proportional counter

13th NEWS-G Collaboration Meeting@Boulby Summer 2023

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

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Spherical Proportional Counters
The detector:~1 mm anodes inside ~0.1-1 m
radius spherical shell
Radial electric field➡Divides detector into
drift and avalanche

Drift Region

V
r
r
V
r
r
V
1
c
a
1
c
a
1
~ =
~r̂ =
E
E
⇡
r
r̂
r̂
⇡
r
a
2
2
2
r rc r ar rc r ar<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>e-<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>

Avalanche Region
Anode

Grounded Rod
Grounded CathodePatrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

17

Spherical Proportional Counters
The detector:~1 mm anodes inside ~0.1-1 m
radius spherical shell
Radial electric field➡Divides detector into
drift and avalanche

Drift Region

V
r
r
V
r
r
V
1
c
a
1
c
a
1
~ =
~r̂ =
E
E
⇡
r
r̂
r̂
⇡
r
a
2
2
2
r rc r ar rc r ar<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>e-<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>

Avalanche Region
Anode

Grounded Rod
Grounded CathodeStrengths in Direct DM Searches:
Choice of gas targets and pressures
Low capacitance, single-electron detection
Lowest surface area to volume ratio
Fiducialisation
Simple, few-channel read-out
Radiopure construction

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

17

1/σSI dR/dER [cm kg day keV ]-1

mχ=1 GeV/c2
H
C
Si
Ge

1043
1042

-1

Drift Region

He
Ne
Ar
Xe

1041

V
r
r
V
r
r
V
1
c
a
1
c
a
1
10
~ =
~r̂ =
E
E
⇡
r
r̂
r̂
⇡
r
a
2
2
2
10
r rc r ar rc r ar<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>-2

The detector:~1 mm anodes inside ~0.1-1 m
radius spherical shell
Radial electric field➡Divides detector into
drift and avalanche-1

Spherical Proportional Counters

1044

e-

<latexit sha1_base64="5BaKEmR38ut+KQ4yxtm+5AvCq0M=">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</latexit>

40
39

1038

Avalanche Region

1037

Anode

36

10

10−2

10−1

1

Grounded Rod
Grounded Cathode10
ER [keV]Strengths in Direct DM Searches:
Choice of gas targets and pressures
Low capacitance, single-electron detection
Lowest surface area to volume ratio
Fiducialisation
Simple, few-channel read-out
Radiopure construction

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

17

Spherical Proportional Counters

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

18

Spherical Proportional Counters

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

18

Rise Time [µs]Pulse-Shape Discrimination
Lots of information in a pulse. e.g. in rise time
Electron from larger radii diffuse more
➡Larger spread in arrival → higher pulse rise time/width
Spatially extended primary ionisation results in higher
rise time/width
Fiducialisation/Particle ID by pulse-shape discrimination65⌀30 cm detector, 1.3 bar
He:Ar:CH4 (51.7:46%:2.3%)
55Fe source inside detector

45

60

40

55

35

50

30

3

45

25

40

20

35

2

30

15

25

1

20

1

0

10

2

4

6

5

8 10 12 14 16 18 20
3
Amplitude [10 ADU]

0(1) X-rays in volume, (2) X-rays
near shell, (3) Cosmic muons
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

19

Rise Time [µs]Pulse-Shape Discrimination
Lots of information in a pulse. e.g. in rise time
Electron from larger radii diffuse more
➡Larger spread in arrival → higher pulse rise time/width
Spatially extended primary ionisation results in higher
rise time/width
Fiducialisation/Particle ID by pulse-shape discrimination65⌀30 cm detector, 1.3 bar
He:Ar:CH4 (51.7:46%:2.3%)
55Fe source inside detector

45

60

40

55

35

50

30

3

45

25

40
Primary Electron Diffusion → Pulse Rise time

20

35

2

30

15

25

1

20

1

2

0

10

2

4

6

5

8 10 12 14 16 18 20
3
Amplitude [10 ADU]

0(1) X-rays in volume, (2) X-rays
near shell, (3) Cosmic muons
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

19

Rise Time [µs]Pulse-Shape Discrimination
Lots of information in a pulse. e.g. in rise time
Electron from larger radii diffuse more
➡Larger spread in arrival → higher pulse rise time/width
Spatially extended primary ionisation results in higher
rise time/width
Fiducialisation/Particle ID by pulse-shape discrimination65⌀30 cm detector, 1.3 bar
He:Ar:CH4 (51.7:46%:2.3%)
55Fe source inside detector

45

60

40

55

35

50

30

3

45

25

40

20

35

Primary Electron Diffusion → Pulse Rise time

2

30

15

25

1

20

1

2

3

0

10

2

4

6

5

8 10 12 14 16 18 20
3
Amplitude [10 ADU]

0(1) X-rays in volume, (2) X-rays
near shell, (3) Cosmic muons
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

19

First NEWS-G Detector, SEDINEFirst NEWS-G results in 2018: ⌀60 cm prototype in LSM, France
Ne:CH4 (99.3%:0.7%) 9.6 kg day exposure
Strongest SI limit at time (2017) on 0.5 GeV candidate
Astropart.Phys. 97 (2018) 54-62
More physics with this data?
“SEDINE”, LSM

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

20

First NEWS-G Detector, SEDINEFirst NEWS-G results in 2018: ⌀60 cm prototype in LSM, France
Ne:CH4 (99.3%:0.7%) 9.6 kg day exposure
Strongest SI limit at time (2017) on 0.5 GeV candidate
Astropart.Phys. 97 (2018) 54-62
More physics with this data?
KK axions produced in the sun Phys.Rev.D 62 (2000) 125011➡Could resolve corona heating problem

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar“SEDINE”, LSM

14/11/2023

20

First NEWS-G Detector, SEDINEFirst NEWS-G results in 2018: ⌀60 cm prototype in LSM, France
Ne:CH4 (99.3%:0.7%) 9.6 kg day exposure
Strongest SI limit at time (2017) on 0.5 GeV candidate
Astropart.Phys. 97 (2018) 54-62
More physics with this data?
KK axions produced in the sun Phys.Rev.D 62 (2000) 125011➡Could resolve corona heating problem

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar“SEDINE”, LSM

14/11/2023

20

First NEWS-G Detector, SEDINEFirst NEWS-G results in 2018: ⌀60 cm prototype in LSM, France
Ne:CH4 (99.3%:0.7%) 9.6 kg day exposure
Strongest SI limit at time (2017) on 0.5 GeV candidate
Astropart.Phys. 97 (2018) 54-62
More physics with this data?
KK axions produced in the sun Phys.Rev.D 62 (2000) 125011➡Could resolve corona heating problem“SEDINE”, LSM

Phys.Rev.D 105 (2022) 1, 012002

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

20

First NEWS-G Detector, SEDINEFirst NEWS-G results in 2018: ⌀60 cm prototype in LSM, France
Ne:CH4 (99.3%:0.7%) 9.6 kg day exposure
Strongest SI limit at time (2017) on 0.5 GeV candidate
Astropart.Phys. 97 (2018) 54-62
More physics with this data?
KK axions produced in the sun Phys.Rev.D 62 (2000) 125011➡Could resolve corona heating problem“SEDINE”, LSM

Phys.Rev.D 105 (2022) 1, 012002

But where next?
💡Development in instrumentation, detector
physics, and detector simulation required fornext generation of NEWS-G 💡

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

20

Simulation Framework
Many packages available for detector simulation:
Geant4: for simulation particle interactions with matter
ANSYS: finite-element methods software for electric field calculations
Garfield++: For simulating electron-ion drift and signal calculations✓Interfaces with Magboltz, SRIM and HEED
Simulation framework combines these with custom calculations toform complete simulation
In use by NEWS-G, R2D2 and for detector R&D

JINST 15 (2020) 06, C06013

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

21

Simulation Chain
1000 37Ar decays
G4RadioactiveDecay
Magboltz gas
parametersGainparameterised
by Polya

Simulatedrecorded pulse
JINST 15 (2020) 06, C06013
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

22

Multi-Anode Readout: ACHINOSSingle anode: drift and avalanche fields coupled➡E≃V·ra/r2 → higher voltage for same field at high r➡Challenge to scale detector size or pressure

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

Individual anode: JINST 13 (2018) 11, P11006
Simulation framework: JINST 15 (2020) 06, C06013

14/11/2023

23

Multi-Anode Readout: ACHINOSSingle anode: drift and avalanche fields coupled➡E≃V·ra/r2 → higher voltage for same field at high r➡Challenge to scale detector size or pressure
Idea: multiple anodes at fixed radius - ACHINOS➡Avalanche field: anode radius + voltage➡Drift field: Collective field of anodes
Process industrialisation: 3D printing and DLC coating

Individual anode: JINST 13 (2018) 11, P11006
Simulation framework: JINST 15 (2020) 06, C06013

JINST 15 (2020) 11, 11

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

23

Multi-Anode Readout: ACHINOSSingle anode: drift and avalanche fields coupled➡E≃V·ra/r2 → higher voltage for same field at high r➡Challenge to scale detector size or pressure
Idea: multiple anodes at fixed radius - ACHINOS➡Avalanche field: anode radius + voltage➡Drift field: Collective field of anodes
Process industrialisation: 3D printing and DLC coating

Individual anode: JINST 13 (2018) 11, P11006
Simulation framework: JINST 15 (2020) 06, C06013~7x

JINST 15 (2020) 11, 11

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

23

Multi-Anode Readout: ACHINOS

Individual anode: JINST 13 (2018) 11, P11006

Single anode: drift and avalanche fields coupled➡E≃V·ra/r2 → higher voltage for same field at high r➡Challenge to scale detector size or pressure
Idea: multiple anodes at fixed radius - ACHINOS➡Avalanche field: anode radius + voltage➡Drift field: Collective field of anodes
Process industrialisation: 3D printing and DLC coating

Simulation framework: JINST 15 (2020) 06, C06013~7x

JINST 15 (2020) 11, 11

SNOLAB

Enabled larger detectors, higher pressures
Key for NEWS-G DM searches
Energy resolution key to 0νββ searches: R2D2
Exploring application to liquid Xe for S2

JINST 16 (2021) 03, P03012

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

23

Multi-Anode Readout: ACHINOSSingle anode: drift and avalanche fields coupled➡E≃V·ra/r2 → higher voltage for same field at high r➡Challenge to scale detector size or pressure
Idea: multiple anodes at fixed radius - ACHINOS➡Avalanche field: anode radius + voltage➡Drift field: Collective field of anodes
Process industrialisation: 3D printing and DLC coating

Individual anode: JINST 13 (2018) 11, P11006
Simulation framework: JINST 15 (2020) 06, C06013~7x

JINST 15 (2020) 11, 11

SNOLAB

Enabled larger detectors, higher pressures
Key for NEWS-G DM searches
JINST 16 (2021) 03, P03012
Energy resolution key to 0νββ searches: R2D2
Exploring application to liquid Xe for S2 (will come back to this!)
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

23

ACHINOS Response: 2-Channel Read-Out
Early ACHINOS read out all anodes together
Experimentally observed amplitude dependance on source azimuthal position
Investigated with simulation

DLC-CoatedCentral Electrode
Anode
Fe

Grounded Rod

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

24

ACHINOS Response: 2-Channel Read-Out

DLC-CoatedCentral Electrode
Anode
Fe

Simulation

18
16

Far Anodes

14

Total

3

Amplitude [10 ADU]

Early ACHINOS read out all anodes together
Experimentally observed amplitude dependance on source azimuthal position
Investigated with simulation

Near Anodes

2200 V on Nearand Far

250
200

12
10

150

8
6

100

4
Grounded Rod

2

50

0
0

50 100 150 200 250 300 350
Azimuthal Angle [deg.]

0Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

24

ACHINOS Response: 2-Channel Read-Out

and Far

3

Amplitude [10 ADU]

Early ACHINOS read out all anodes together
Experimentally observed amplitude dependance on source azimuthal position
Investigated with simulation
Signal on higher on Near anode than Far: Electric field higher due to rod
Increasing voltage applied to Far anodes corrects for effectSimulation18
Now standard practise for bias
2200 V on Near
Far
Anodes16
on 2 ACHINOS channels
250
Near Anodes

DLC-CoatedCentral Electrode
Anode
Fe

14

Total

200

12
10

150

8
6

100

4
Grounded Rod

2

50

0
0

50 100 150 200 250 300 350
Azimuthal Angle [deg.]

0Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

24

ACHINOS Response: 2-Channel Read-Out

Anode
Fe

Total

200

12
10

150

8
6

100

4
Grounded Rod

14

Total

200

12
10

150

8
6

100

4

2

50

0
0

Amplitude [10 ADU]

DLC-CoatedCentral Electrode

14

250

3

and Far

3

Amplitude [10 ADU]

Early ACHINOS read out all anodes together
Experimentally observed amplitude dependance on source azimuthal position
Investigated with simulation
Signal on higher on Near anode than Far: Electric field higher due to rod
Increasing voltage applied to Far anodes corrects for effectSimulation
18
18
Now standard practise for bias
2200 V on Near
30
V
more
on
Far
Far
AnodesFar
Anodes16
16
on 2 ACHINOS channels
250
Near Anodes
Near Anodes

2

50

0
50 100 150 200 250 300 350
Azimuthal Angle [deg.]

0Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar0

50 100 150 200 250 300 350
Azimuthal Angle [deg.]
14/11/2023

024

Individual Anode Read-Out
Developed electronics and read-out to
instrument all 11 anodes individually
Improved energy resolution,fiducialisation, track reconstruction, …
NEW: 2309.15066

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

25

Individual Anode Read-Out
Developed electronics and read-out to
instrument all 11 anodes individually
Improved energy resolution,fiducialisation, track reconstruction, …
NEW: 2309.15066

Data (500 mbar Ar:CH4 2%)
Without individual calibration

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

25

Individual Anode Read-Out
Developed electronics and read-out to
instrument all 11 anodes individually
Improved energy resolution,fiducialisation, track reconstruction, …
NEW: 2309.15066

Data (500 mbar Ar:CH4 2%)
Without individual calibration

With individual calibration

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

25

Individual Anode Read-Out
Developed electronics and read-out to
instrument all 11 anodes individually
Improved energy resolution,fiducialisation, track reconstruction, …

Simulation

✓a

ra

lw

a

NEW: 2309.15066

Data (500 mbar Ar:CH4 2%)
Without individual calibration

With individual calibration

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

25

Event Localisation
Single-anode(channel) → Radial information from rise time
➡Also track vs point-like from rise time

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

26

Event Localisation

Near

Single-anode(channel) → Radial information from rise time
➡Also track vs point-like from rise time
2-channel → +Near/Far information from amplitude asymmetry

SharedFar

11-anode ACHINOS simulation

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

26

Event Localisation

Near

Single-anode(channel) → Radial information from rise time
➡Also track vs point-like from rise time
2-channel → +Near/Far information from amplitude asymmetry
11-channel → +potential for event localisation➡Potential to reconstruct tracks in detector volume
60 anodes → higher field and improved position resolution

SharedFar

60-anode ACHINOS simulation

11-anode ACHINOS simulation

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

26

Event Localisation

Near

Single-anode(channel) → Radial information from rise time
➡Also track vs point-like from rise time
2-channel → +Near/Far information from amplitude asymmetry
11-channel → +potential for event localisation➡Potential to reconstruct tracks in detector volume
60 anodes → higher field and improved position resolution

SharedLight read-out → event t0Far60-anode ACHINOS simulation

11-anode ACHINOS simulation

Nucl.Instrum.Meth.A 1028 (2022) 166382
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

26

Ionisation Quenching Factor

Kinematic matching: low-mass targets are favourable for light-DM detection by nuclear recoils
Light targets have favourable quenching factors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

27

Ionisation Quenching Factor
Stopping and Range of Ions in
Matter (SRIM) simulation

Kinematic matching: low-mass targets are favourable for light-DM detection by nuclear recoils
Light targets have favourable quenching factors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

27

Ionisation Quenching Factor
Stopping and Range of Ions in
Matter (SRIM) simulation

Innovative approach using literature measurements
Astropart.Phys. 141 (2022) 102707

2 measurement approaches in NEWS-G
Phys.Rev.D 105 (2022) 5, 052004➡Neutron scattering at TUNL➡Electron/Ion beam, COMIMAC, Grenoble
Eur.Phys.J.C 82 (2022) 12, 1114

Kinematic matching: low-mass targets are favourable for light-DM detection by nuclear recoils
Light targets have favourable quenching factors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

27

Quenching Factor Measurements: TUNL
Neutron scattering-induced nuclear recoils in SPC → compare to calibration
Recoil Spectrum
Simulated
MeasuredPatrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

28

Quenching Factor Measurements: TUNL
Neutron scattering-induced nuclear recoils in SPC → compare to calibration
Recoil Spectrum
Simulated
Measured

Phys.Rev.D 105 (2022) 5, 052004

2 bar Ne+CH4 (3%)

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

28

Quenching Factor
Measurements:
COMIMACElectrons and ions directed into SPC → compare response
Studied ions 2 - 13 keV, calibrated with e- 1.5 - 13 keV
2

×103

×103
1.2

1.8

6 keV e-1.6

6 keV He+

1

1.4
0.8

1.2
1

0.4
0.2
0
0

2

4

6

8 10 12 14 16 18 20
Amplitude [103 ADU]

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

0.4

ra

ra

0.6

Fo
rI
llu
st

tio
n

0.8

tio
n

0.6

Fo
rI
llu
st

⌀30 cm SPC

1 bar
He:CH4(95:5%)

0.2
0
0

2

4

6

8 10 12 14 16 18 20
Amplitude [103 ADU]

14/11/2023

29

Quenching Factor
Measurements:
COMIMACElectrons and ions directed into SPC → compare response
Studied ions 2 - 13 keV, calibrated with e- 1.5 - 13 keV
2

×103

×103
1.2

1.8

6 keV e-1.6

6 keV He+

1

1.4
0.8

1.2
1

0.4
0.2
0
0

2

4

6

8 10 12 14 16 18 20
Amplitude [103 ADU]

0.4

ra

ra

0.6

Fo
rI
llu
st

tio
n

0.8

tio
n

0.6

Fo
rI
llu
st

⌀30 cm SPC

1 bar
He:CH4(95:5%)

0.2
0
0

100 mbar CH4
2

4

6

8 10 12 14 16 18 20
Amplitude [103 ADU]

Eur.Phys.J.C 82 (2022) 12, 1114

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

29

Quenching Factor Estimates: W-Values
W-value: Average energy required to produce electron-ion pairW different for electrons and ions, and varies with energy➡Difference is quantified by QF
W of electrons and ions in gases prev. studied for dosimetry➡Comparing asymptotic electron W-value and W(E) for ions, get QF
Astropart.Phys. 141 (2022) 102707

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

30

Quenching Factor Estimates: W-Values
W-value: Average energy required to produce electron-ion pairW different for electrons and ions, and varies with energy➡Difference is quantified by QF
W of electrons and ions in gases prev. studied for dosimetry➡Comparing asymptotic electron W-value and W(E) for ions, get QF
Astropart.Phys. 141 (2022) 102707

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

30

Quenching Factor Estimates: W-Values
W-value: Average energy required to produce electron-ion pairW different for electrons and ions, and varies with energy➡Difference is quantified by QF
W of electrons and ions in gases prev. studied for dosimetry➡Comparing asymptotic electron W-value and W(E) for ions, get QF
Astropart.Phys. 141 (2022) 102707

Extends QF knowledge in NEWS-G
gases beyond current measurements!
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

30

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 d234
Pa
91 6.7 hMain source of background iscontaminants in detector copper

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us
210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 d
206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

31

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 d234
Pa
91 6.7 hMain source of background iscontaminants in detector copper

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us
210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 d
206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

31

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 d234
Pa
91 6.7 hMain source of background iscontaminants in detector copper

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us
210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 d
206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

31

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 dMain source of background iscontaminants in detector copper

234
Pa
91 6.7 h

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us

!

210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 d
206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

31

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 dMain source of background iscontaminants in detector copper

234
Pa
91 6.7 h

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us

!

210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 d
206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

31

Overcoming Backgrounds in Copper
238
U
92 4.5 Gy
234
Th
90 24 d234
99.84%
U
92 250 ky
234m
Pa 0.16%91 1.2 m
230
Th
90 24 dMain source of background iscontaminants in detector copper‘High reduction potential’ of copper→ Preferentially deposited
Additive-free, electroforming

234
Pa
91 6.7 h

226
Ra
88 1.6 ky
222
Rn
86 3.8 d
Anode

218
Po
84 3.1 m
214
Pb
82 27 m214
Bi
83 20 m214
Po
84 160 us

!

210
Pb
82 22 y210
Bi83 5 d210
Po
84 138 dCu
Oxidation

206
Pb
82 Stable

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

CathodeReduction

Cu

Cu

+2e

Cu

U

+3e

U

Electrolyte
CuU

14/11/2023

31

Ultra-Pure Copper Electroforming
500 μm electroplated layer to NEWS-G detector inner surface
Demonstrated potential to electroform full detector on
feasible time scale
Pb

500 m
EF Copper

Gas

4N Copper

Po
Bi

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

32

Ultra-Pure Copper Electroforming
500 μm electroplated layer to NEWS-G detector inner surface
Demonstrated potential to electroform full detector on
feasible time scale
Pb

500 m
EF Copper

Gas

4N Copper

Po
Bi

LSM

LSM
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

32

Ultra-Pure Copper Electroforming
500 μm electroplated layer to NEWS-G detector inner surface
Demonstrated potential to electroform full detector on
feasible time scale
Pb

500 m
EF Copper

Gas

4N Copper

Po
Bi

LSM

ICP-MS Assay~1 mm/month

NIMA 988 (2021) 164844

LSM
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

32

SNOGLOBE in SNOLAB⌀140 cm detector 4N (99.99% pure) Aurubis copper➡Electroplated internal layer
Constructed and tested in LSM, France✓Commissioning data analysis finalising (CH4)S140 in LSM

40 cm HDPE
22 cm Low
Activity Lead
3 cm ArcheologicalLead

135 mbar CH4
JINST 18 (2023) 02, T02005
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

33

SNOGLOBE in SNOLAB⌀140 cm detector 4N (99.99% pure) Aurubis copper➡Electroplated internal layer
Constructed and tested in LSM, France✓Commissioning data analysis finalising (CH4)

Discriminating variable: time separation
Surface/volume and coincidence
discrimination
Raw

40 cm HDPE
22 cm Low
Activity Lead
3 cm Archeological
Lead

Processed
Time separation

135 mbar CH4
JINST 18 (2023) 02, T02005
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

33

SNOGLOBE in SNOLAB⌀140 cm detector 4N (99.99% pure) Aurubis copper➡Electroplated internal layer
Constructed and tested in LSM, France✓Commissioning data analysis finalising (CH4)

40 cm HDPE
22 cm Low
Activity Lead
3 cm ArcheologicalLead

135 mbar CH4
JINST 18 (2023) 02, T02005
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

33

SNOGLOBE in SNOLAB⌀140 cm detector 4N (99.99% pure) Aurubis copper➡Electroplated internal layer
Constructed and tested in LSM, France✓Commissioning data analysis finalising (CH4)

40 cm HDPE
22 cm Low
Activity Lead
3 cm Archeological
Lead

y
r
a
n
i
m
i
l
re

P

135 mbar CH4
JINST 18 (2023) 02, T02005
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

33

SNOGLOBE in SNOLAB⌀140 cm detector 4N (99.99% pure) Aurubis copper➡Electroplated internal layer
Constructed and tested in LSM, France✓Commissioning data analysis finalising (CH4)First physics run in SNOLAB finished early 2023✓~20 kg·days exposure with Ne:CH4
S140
SNOLAB

y
r
a
n
i
m
i
l
re

P

135 mbar CH4

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

33

SPC Applications: Neutron Spectroscopy
Background measurements for rare-event searches
Medical and industrial applications

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

34

SPC Applications: Neutron Spectroscopy
Background measurements for rare-event searches
Medical and industrial applications
3He and BF3: expensive, toxic, fast through moderation

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

34

SPC Applications: Neutron Spectroscopy
Background measurements for rare-event searches
Medical and industrial applications
3He and BF3: expensive, toxic, fast through moderation

SPC as neutron spectrometer with N2 gas
14N + n → 14C + p + 625 keV
14N + n → 11B + α- 159 keV

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

34

SPC Applications: Neutron Spectroscopy
Background measurements for rare-event searches
Medical and industrial applications

MC40 Cyclotron U. Of Birmingham

3He and BF3: expensive, toxic, fast through moderation

SPC as neutron spectrometer with N2 gas
14N + n → 14C + p + 625 keV
14N + n → 11B + α- 159 keV

University of Birmingham
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

34

SPC Applications: Neutron Spectroscopy
Background measurements for rare-event searches
Medical and industrial applications

MC40 Cyclotron U. Of Birmingham

3He and BF3: expensive, toxic, fast through moderation

SPC as neutron spectrometer with N2 gas
14N + n → 14C + p + 625 keV
14N + n → 11B + α- 159 keV

Simulation

1.5 bar N2

NIMA 1049 (2023) 168124

University of Birmingham
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

34

Exploring Uncharted Territory
Rept.Prog.Phys. 85 (2022) 5, 056201

Light DM searches through→Novel detector technologies→Innovative uses of existing detectors→Future detectors

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

35

Towards the Neutrino Floor with NEWS-G
Simulated backgrounds in SNOGLOBE

Cosmogenic activation(1 year cooling)
20.4%

Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Current detectors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

Towards the Neutrino Floor with NEWS-G
Simulated backgrounds in SNOGLOBE

Cosmogenic activation(1 year cooling)
20.4%

Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Electroforming…
Current detectors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

Towards the Neutrino Floor with NEWS-G
Simulated backgrounds in SNOGLOBE…undergroundCosmogenic activation(1 year cooling)
20.4%

Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Electroforming…
Current detectors
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

Towards the Neutrino Floor with NEWS-G
Simulated backgrounds in SNOGLOBE…undergroundCosmogenic activation(1 year cooling)
20.4%

Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Electroforming…
Current detectors

Future NEWS-G DM projects
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

Towards the Neutrino Floor with NEWS-G
Simulated backgrounds in SNOGLOBE…undergroundCosmogenic activation(1 year cooling)
20.4%

Water-based shield
Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Electroforming…
Current detectors

Future NEWS-G DM projects
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

Towards the Neutrino Floor with NEWS-G
arXiv:2301.05183 accepted by PRD

Simulated backgrounds in SNOGLOBE…undergroundCosmogenic activation(1 year cooling)
20.4%

Water-based shield
Shield materials
SEDINESNOGLOBE

ECuME

DarkSPHEREcm
NOSV Cucm
99.99% Cu
500 m EFCu Layer

cm
EF Cu

cm
EF Cu

19.8%

Copper
54.4%

Gas mixture
4.8%
Cavern0.6%

Electroforming…
Current detectors

Future NEWS-G DM projects
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

36

DarkSPHERE in Boulby

222Rn ~3 Bq/m3

P. Scovell, DMUK 2019μ ~4⨉10-8 /cm2/s NIMA 511 (2003) 347-353

DarkSPHERE will use a modular water-based shield
A pure water shield is sufficient for background goal of
0.01 event/keV/kg/day in ROI
Boulby as potential host - UK’s deep-underground science facility

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

37

DarkSPHERE in Boulby

222Rn ~3 Bq/m3

P. Scovell, DMUK 2019μ ~4⨉10-8 /cm2/s NIMA 511 (2003) 347-353

DarkSPHERE will use a modular water-based shield
A pure water shield is sufficient for background goal of
0.01 event/keV/kg/day in ROI
Boulby as potential host - UK’s deep-underground science facility

Current ⌀30cm R&D SPC!
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

37

DarkSPHERE in Boulby

222Rn ~3 Bq/m3

P. Scovell, DMUK 2019μ ~4⨉10-8 /cm2/s NIMA 511 (2003) 347-353

DarkSPHERE will use a modular water-based shield
A pure water shield is sufficient for background goal of
0.01 event/keV/kg/day in ROI
Boulby as potential host - UK’s deep-underground science facility

Current ⌀30cm R&D SPC!
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

37

DarkSPHERE in Boulby

222Rn ~3 Bq/m3

P. Scovell, DMUK 2019μ ~4⨉10-8 /cm2/s NIMA 511 (2003) 347-353

DarkSPHERE will use a modular water-based shield
A pure water shield is sufficient for background goal of
0.01 event/keV/kg/day in ROI
Boulby as potential host - UK’s deep-underground science facility

Conceptual design fits in
Large Experiment Cavern

Current ⌀30cm R&D SPC!
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

37

Towards DarkSPHERE

Example electroforming bathat Pacific Northwest National Laboratory

ECuME project, SNOLAB, of ⌀140cm detector + scale model in PNNLSTFC funding for an ultra-pure EFCu facility underground in Boulby➡Facility design, operation and management
Currently under construction

Credit: E W Hoppe, PNNL

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

38

Towards DarkSPHERE

Example electroforming bathat Pacific Northwest National Laboratory

ECuME project, SNOLAB, of ⌀140cm detector + scale model in PNNLSTFC funding for an ultra-pure EFCu facility underground in Boulby➡Facility design, operation and management
Currently under construction
Boulby EFCu
Facility
Credit: E W Hoppe, PNNL

Boulby-EFCu: Larger Bath Design
Scale: 1:20
Patrick Knights

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

38

Towards DarkSPHERE

Example electroforming bathat Pacific Northwest National Laboratory

ECuME project, SNOLAB, of ⌀140cm detector + scale model in PNNLSTFC funding for an ultra-pure EFCu facility underground in Boulby➡Facility design, operation and management
Currently under construction
Boulby EFCu
Facility
Credit: E W Hoppe, PNNLFirst EFCu test in Boulby (Feb ’23)

Boulby-EFCu: Larger Bath Design
Scale: 1:20
Patrick Knights

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

38

Towards DarkSPHERE

Example electroforming bathat Pacific Northwest National Laboratory

ECuME project, SNOLAB, of ⌀140cm detector + scale model in PNNLSTFC funding for an ultra-pure EFCu facility underground in Boulby➡Facility design, operation and management
Currently under construction
Boulby EFCu
Facility
Credit: E W Hoppe, PNNLFirst EFCu test in Boulby (Feb ’23)

Boulby-EFCu: Larger Bath Design
Scale: 1:20
Patrick Knights

Construction of bath underway
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

38

Towards DarkSPHERE

Example electroforming bathat Pacific Northwest National Laboratory

ECuME project, SNOLAB, of ⌀140cm detector + scale model in PNNLSTFC funding for an ultra-pure EFCu facility underground in Boulby➡Facility design, operation and management
Currently under construction⌀30cm prototype with world-leading
Boulby EFCu
physics potential to begin
Facility
construction early next year!
Credit: E W Hoppe, PNNLFirst EFCu test in Boulby (Feb ’23)

Boulby-EFCu: Larger Bath Design
Scale: 1:20
Patrick Knights

Construction of bath underway
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

38

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes~7x

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes
Wire

Anode

rs
CentralElectrode~7x

Support Rod

25%-scale 3D-printed prototype
based on the truncated icosahedron
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes
Wire

Anode

rs
CentralElectrode~7x

Support Rod

25%-scale 3D-printed prototype
based on the truncated icosahedron
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes
Wire

Anode

rs
CentralElectrode~7x

Support Rod

25%-scale 3D-printed prototype
based on the truncated icosahedron
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes
Wire

Anode

~33x
rs
CentralElectrode~7x

Support Rod

25%-scale 3D-printed prototype
based on the truncated icosahedron
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

Instrumentation for DarkSPHERE
Current ACHINOS thought to be sufficient for S140
To maintain same drift field in DarkSPHERE, needlarger ACHINOSMoving towards a 60-anode ACHINOS with 1mm(or smaller) anodes
Wire

Anode

~33x
rs
CentralElectrode~7x

Support Rod

25%-scale 3D-printed prototype
based on the truncated icosahedron
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

39

DarkSPHERE Physics Potential‘Neutrino-floor’ reaching potential in DM-nucleon SI interactions
World-leading potential in SD interactions through natural-abundance H and C isotopes⌀30cm prototype in Boulby in a DarkSPHERE-like shield will have world-leading sensitivity
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

40

DarkSPHERE Physics Potential‘Neutrino-floor’ reaching potential in DM-nucleon SI interactions
World-leading potential in SD interactions through natural-abundance H and C isotopes⌀30cm prototype in Boulby in a DarkSPHERE-like shield will have world-leading sensitivity
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

40

DarkSPHERE Physics Potential‘Neutrino-floor’ reaching potential in DM-nucleon SI interactions
World-leading potential in SD interactions through natural-abundance H and C isotopes⌀30cm prototype in Boulby in a DarkSPHERE-like shield will have world-leading sensitivity
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/202340

10-32

10

CD
EX

-34

⌀ 3 m, 5 bar, 300 days

10-2

)

90% CL Upper Limit

.
ig

Dar
kS

He: i-C4 H10 (90%:10%)
Sensitivity from He

10-40

ig.
)

(M

10-36

10-38

(M

T
N1
NO
XE

DM-nucleon σSI [cm2 ]DarkSPHERE Physics Potential

PH
ERE

Mig

dal
(n

Dark
SPH
ERE
Migd
al

e - ≥2)(ne - ≥
1)

10-1

DM mass mχ [GeV/c2 ]Enhanced sensitivity through MIGDAL effect in nuclear scattering
Sensitivity to electron scattering through low threshold
Large sphere is also ideal shape to study more exotic candidates
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

41

10

CD
EX

-34

90% CL Upper Limit
He: i-C4 H10 (90%:10%)
Sensitivity from He⌀ 3 m, 5 bar, 300 days

10-40

10

-2

)

Dar
kS

.
ig

10

ig.
)

(M

10-36

-38

(M

PH
ERE

Mig

dal
(n

Dark
SPH
ERE
Migd
al

DM-electron σ e [cm2 ]

10-32

T
N1
NO
XE

DM-nucleon σSI [cm2 ]DarkSPHERE Physics Potential
10-34

10-36

10

10-40
1

2

DM mass mχ [GeV/c ]Freeze-in

- ≥2)
n
(
e
E
R
kSPHE

10-38

)

-1

EI

S
SEN

Dar

e - ≥2(ne - ≥
1)

N10
O
N
XE

90% CL Upper Limit
He: i -C4 H10 (90%:10%)⌀ 3 m, 5 bar, 300 days

10

E
R
E
PH
S
k
r
Da

1)
≥
(n e
-

FDM =(α me /q)2

102

103

DM mass mχ [MeV/c2 ]Enhanced sensitivity through MIGDAL effect in nuclear scattering
Sensitivity to electron scattering through low threshold
Large sphere is also ideal shape to study more exotic candidates
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

41

90% CL Upper Limit
He: i-C4 H10 (90%:10%)
Sensitivity from He⌀ 3 m, 5 bar, 300 days

10

-40

10

-2

PH
ERE

Mig

dal
(n

Dark
SPH
ERE
Migd
al

10-34

10-36

10

10

10-40
1

2

DM mass mχ [GeV/c ]Freeze-in

- ≥2)
n
(
e
E
R
kSPHE

Mica

10-18

10

Ohya

DEAP-3600-20

XENON1T

-38

)

-1

EI

S
SEN

Dar

e - ≥2(ne - ≥
1)

N10
O
N
XE

DarkSPHERE

)

Dar
kS

.
ig

10

ig.
)

(M

10-36

-38

(M

DM-nuclear σC [cm2 ]

10

CD
EX

-34

DM-electron σ e [cm2 ]

10-32

T
N1
NO
XE

DM-nucleon σSI [cm2 ]DarkSPHERE Physics Potential

90% CL Upper Limit
He: i -C4 H10 (90%:10%)⌀ 3 m, 5 bar, 300 days

10

E
R
E
PH
S
k
r
Da

1)
≥
(n e

10-22

-

FDM =(α me /q)

He: i-C4 H10 (90%:10%)
2

102

103

DM mass mχ [MeV/c2 ]10-24 1510

⌀ 3 m, 5 bar, 3 years

1016

1017

1018

1019

1020

1021

DM mass mχ [GeV/c 2 ]Enhanced sensitivity through MIGDAL effect in nuclear scattering
Sensitivity to electron scattering through low threshold
Large sphere is also ideal shape to study more exotic candidates
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

41

Towards S2 Signal in Spherical LXe TPC
Similarities between the spherical proportional counter and XMASS are striking➡SPC: Charge-only, and gas. XMASS: Light-only, liquid Xenon
Question: Could sensitivity be improved further if fiducialisation/background rejection improved?
➡Can this be done by adding charge-amplification to get S2 signal?
XMASS recently published results of full data set+
Phys.Rev.D 108 (2023) 8, 083022

Source: XMASS website
Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

42

Test Set-Up
Project challenges and developed solutions➡Sparking at feedthrough → Kapton protection sleeve➡Sparking from needle → grounded resistive glass holder
Tests with ⌀50μm-tip needle mounted inside test vessel
Installed with 241Am source, and volume observed by 2 PMTs

LXe

PMT
Field cage
NeedleInsulated Cu wires (HV and ground)Am

Insulated Cu wire

⌀1 mm glass capillary tube

NeedleSHV

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

43

Test Set-Up
Project challenges and developed solutions➡Sparking at feedthrough → Kapton protection sleeve➡Sparking from needle → grounded resistive glass holder
Tests with ⌀50μm-tip needle mounted inside test vessel
Installed with 241Am source, and volume observed by 2 PMTs

LXe

PMT
Field cage
NeedleInsulated Cu wires (HV and ground)Am

Insulated Cu wire

⌀1 mm glass capillary tube

NeedleSHV

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

43

Test Set-Up
Project challenges and developed solutions➡Sparking at feedthrough → Kapton protection sleeve➡Sparking from needle → grounded resistive glass holder
Tests with ⌀50μm-tip needle mounted inside test vessel
Installed with 241Am source, and volume observed by 2 PMTs

LXe

PMT
Field cage
NeedleInsulated Cu wires (HV and ground)eAm

Insulated Cu wire

⌀1 mm glass capillary tube

NeedleSHV

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

43

First Observation of S2 with Needle
Last week, filled chamber with 270 LXe and cooled
Data taking 8-10/11

Preliminary

Preliminary

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

44

First Observation of S2 with Needle
Last week, filled chamber with 270 LXe and cooled
Data taking 8-10/11
We see S2 in LXe with the needle!
Demonstrated S2 with needle with voltages of >3kV
Future work: Improve robustness of needle holder,
PMT stability

Preliminary

Preliminary

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

44

First Observation of S2 with Needle
Last week, filled chamber with 270 LXe and cooled
Data taking 8-10/11
We see S2 in LXe with the needle!
Demonstrated S2 with needle with voltages of >3kV
Future work: Improve robustness of needle holder,
PMT stability

Preliminary

Preliminary

S1

S2

Preliminary
5.5 kV

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

44

Summary
Search for light dark matter has growing interest
Two complementary ways to search presented: Novel detectors
with light targets and novel nuclear effects
MIGDAL is taking data with OTPC, analysing first data
NEWS-G completed first physics campaign in SNOLAB this year,
analysis ongoing
Fully electroformed SPCs will overcome main background➡Prototype towards DarkSPHERE to begin construction this year

y
r
a
n
i
m
i
rel

P

Patrick Knights - NEWS-G and MIGDAL - Kamioka Laboratory Seminar

14/11/2023

45