Development of Liquid Nitrogen Time Projection Chambers

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Development of Liquid Nitrogen Time Projection
Chambers A. Ereditato, M. Hess, S. Janos, I.
Kreslo, S. Lehmann, M. Messina, U. Moser, B.
Rossi, H.-U. Schütz, M. Zeller Presented by
Igor E. Kreslo, Ph.D. LHEP, University of Bern
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Multi-energy X-ray cargo radiography can still
something be hidden?
Sensitive to Metal objects High density
objects Characteristic shapes
Not very sensitive to Specific chemical
composition 2D shaped objects (sheet explosives)
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Gamma Nuclear Resonant Absorption method of
Nitrogen detection (Soreq NRC, 1985)
9.17 MeV ?
1.5 MeV
14N
13C
p
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Gamma Nuclear Resonant Absorption method of
Nitrogen detection (Proposed by Soreq NRC to US
FAA in 1985)
Detector
Intensity
Non-Resonant ?
Resonant ?
14N
13C
p
14N
e-
N content
e-
Sorec National Research Center, Yavne, 81800,
Israel
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Detector for GRNA radiography
High spatial resolution (order of 1 mm or
better) Large active volume High density High
Nitrogen content
TPC on liquid Noble gases (LAr, LXe) LNitrogen ?
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Ionisation signals in Liquid Argon - Nitrogen
Plans and Perspectives
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Charge transport in Liquid Argon - Nitrogen
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Electron mobility in Liquid Argon - Nitrogen
Detector scheme
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LAR TPC prototype
Mixture LAr-LN is prepared directly in the
cryostat. The content of Nitrogen is monitored by
density sensor. ?LAr 1.4 g/cm3 ?LN 0.8
g/cm3 Density sensor
Floater
C f(?)
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LAR TPC prototype
Wire pitch 2 mm
HV power supply 0-30kV
100 x 100 mm
To preamp
8mm
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LAr TPC prototype
Argon used Carbagas 1, Commercial grade 48 (
lt 210-7 impurities concentration)
Nitrogen used Carbagas, Commercial grade 50
( lt 10-7 impurities concentration) No
additional purification is done for the first
tests.
1 Carbagas, Hofgut, 3073 Gumligen , Switzerland
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LAR TPC prototype and performance
Detector readout, amplifier, DAQ
CAEN V1724 VME 8xADC
Shaping Q-integrating preamplifier, 25 mV/fC
Wire chamber
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LAR TPC prototype and performance
Muon
0-30 kV
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LAR TPC prototype and performance
Cosmic Muon Tracks recorded
5 mm drift
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LAr TPC prototype and performance
TPC response to a primary ionization
Recombination losses q0AQ0
Primary ionisation Q0
Attachment losses qq0e -(D/?)
Particle
E
collection wires
I-
Ar e-
I-
I-
Ar e-
e-
D, drift distance
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LAR TPC prototype and performance
TPC response to a Compton electrons - simulation
Losses during the charge drift affect the shape
of the spectrum, but not the end point ! End
point can be used to measure recombination.
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LAR TPC prototype and performance
TPC response to Compton electrons from 60Co (1.17
and 1.33 MeV gammas) (measured data)
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LAR TPC prototype and performance
60Co (1.17 and 1.33 MeV gammas)
Box model
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LARN TPC prototype and performance
60Co (1.17 and 1.33 MeV gammas)
Recombination vs Nitrogen content (vol. )
A1
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LARN TPC prototype and performance
Recombination vs Nitrogen content, (vol. )
A0.5
A1
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LARN TPC prototype and performance
Recombination vs Nitrogen content, (vol. )
A0.5
Similar effect was observed by D.W. Swan in
1963, with about 0.6 vol. of LN ( for
reference see slide 7) but not explained !
A1
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LARN TPC prototype and performance
Box model parameters evolution with LN content
(vol. )
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LARN TPC first test conclusions

• First prototype TPC with Liquid Argon-Nitrogen
  mixture operates well in Bern.
• Collected charge at 8 mm drift and 6 vol. of
  Nitrogen is sufficient to see MIPs and 1 MeV
  electrons (signal / noise gt10).
• At 6 of Nitrogen such TPC is already more
  efficient for GRNA, than liquid scintillator
  detectors.
• Further study on recombination mechanisms in
  LAr-N is needed.
• The technology is very promising for security
  applications !

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LARN TPC Plans and Perspectives

• More detailed study on recombination vs Nitrogen
  content with non-resonant gammas.
• Study of charge attachment cross-section vs
  Nitrogen content.
• 3. Proton - electron separation study
  (simulation)
• 4. Tests with resonant gammas on a proton
  accelerator.
• 5. Optimization of the detector geometry for
  GRNA scenario.
• 6. Contacts with industry - building a cargo
  screener prototype