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Development of Liquid Nitrogen Time Projection Chambers

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Development of Liquid Nitrogen Time Projection Chambers ... U. Moser, B. Rossi, H.-U. Sch tz, M. Zeller. Presented by Igor E. Kreslo, Ph.D. ... – PowerPoint PPT presentation

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Title: Development of Liquid Nitrogen Time Projection Chambers


1
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
2
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)
3
Gamma Nuclear Resonant Absorption method of
Nitrogen detection (Soreq NRC, 1985)
9.17 MeV ?
1.5 MeV
14N
13C
p
4
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
5
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 ?
6
Ionisation signals in Liquid Argon - Nitrogen
Plans and Perspectives
7
Charge transport in Liquid Argon - Nitrogen
8
Electron mobility in Liquid Argon - Nitrogen
Detector scheme
9
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(?)
10
LAR TPC prototype
Wire pitch 2 mm
HV power supply 0-30kV
100 x 100 mm
To preamp
8mm
11
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
12
LAR TPC prototype and performance
Detector readout, amplifier, DAQ
CAEN V1724 VME 8xADC
Shaping Q-integrating preamplifier, 25 mV/fC
Wire chamber
13
LAR TPC prototype and performance
Muon
0-30 kV
14
LAR TPC prototype and performance
Cosmic Muon Tracks recorded
5 mm drift
15
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
16
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.
17
LAR TPC prototype and performance
TPC response to Compton electrons from 60Co (1.17
and 1.33 MeV gammas) (measured data)
18
LAR TPC prototype and performance
60Co (1.17 and 1.33 MeV gammas)
Box model
19
LARN TPC prototype and performance
60Co (1.17 and 1.33 MeV gammas)
Recombination vs Nitrogen content (vol. )
A1
20
LARN TPC prototype and performance
Recombination vs Nitrogen content, (vol. )
A0.5
A1
21
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
22
LARN TPC prototype and performance
Box model parameters evolution with LN content
(vol. )
23
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 !

24
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
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