Development of Liquid Nitrogen Time Projection Chamber
A. Ereditato, M. Hess, S. Janoŝ, I. Kreslo, M. Messina,
U. Moser, B. Rossi, H.-U. Schütz, M. Zeller
Presented by Igor E. Kreslo, Ph.D.
LHEP, University of Bern
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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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)
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
2
Gamma Nuclear Resonant Absorption method of Nitrogen
detection
(Soreq NRC,Israel, 1985)
9.17 MeV γ
I.Kreslo
14N
13C
p
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
~1.5 MeV
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Gamma Nuclear Resonant Absorption method of Nitrogen
detection
(Proposed by Soreq NRC* to US FAA in 1985)
Detector
Non-Resonant
Resonant
γ
e-e
γ
14N
14N
Intensity
13C
e-
p
eeee-
N content
* Sorec National Research Center, Yavne, 81800, Israel
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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Detector for GRNA radiography
High spatial resolution (order of 1 mm or better)
Large active volume
TPC on liquid
Noble gases
(LAr, LXe)
High density
High Nitrogen content
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
LNitrogen ?
5
Ionisation signals in Liquid Argon - Nitrogen
Plans and Perspectives
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
6
Charge transport in Liquid Argon - Nitrogen
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
7
Electron mobility in Liquid Argon - Nitrogen
Detector scheme
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
8
LAR TPC prototype
Mixture LAr-LN is prepared directly
in cryostat. The content of Nitrogen
is monitored by density sensor.
ρLAr = 1.4 g/cm3
ρLN = 0.8 g/cm3
Density sensor:
Floater
C = f(ρ)
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
9
LAR TPC prototype
Wire pitch
2 mm
100 x 100 mm
HV power supply
0-30kV
To preamp
8mm
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
10
LAR TPC prototype
Argon used:
Carbagas 1,
Commercial grade “48” ( < 2*10-7 impurities concentration)
Nitrogen used:
Carbagas,
Commercial grade “50” ( < 10-7 impurities concentration)
No additional purification is done for the first tests.
1 Carbagas,
I.Kreslo
Hofgut, 3073 Gumligen , Switzerland
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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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
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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LAR TPC prototype and performance
Muon
0-30 kV
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
13
LAR TPC prototype and performance
Cosmic Muon Tracks recorded
~ 5 mm drift
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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LAR TPC prototype and performance
TPC response to a primary ionisation
Primary
ionisation Q0
Particle
Recombination
losses q0=A*Q0
Attachment
losses q=q0e -(D/λ)
E
I-
Ar+ eI-
Ar+
I-
e-
eD, drift distance
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
15
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.
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
16
LAR TPC prototype and performance
TPC response to Compton electrons from 60Co (1.17 and 1.33 MeV gammas)
(measured data)
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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LAR TPC prototype and performance
60Co
(1.17 and 1.33 MeV gammas)
“Box model” :
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
18
LAR+N TPC prototype and performance
60Co
(1.17 and 1.33 MeV gammas)
Recombination vs Nitrogen content (vol. %)
A=1
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
19
LAR+N TPC prototype and performance
Recombination vs Nitrogen content, (vol. %)
A~0.5
A=1
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
20
LAR+N TPC prototype and performance
Recombination vs Nitrogen content, (vol. %)
A~0.5
A=1
I.Kreslo
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 !
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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LAR+N TPC prototype and performance
Betha
A
Box model parameters evolution with LN content (vol. %)
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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LAR+N TPC first test conclusions
1. First prototype TPC on Liquid Argon-Nitrogen mixture operates well.
2. Collected charge at 8 mm drift and 6 vol. % of Nitrogen is sufficient to
see MIPs and 1 MeV electrons (signal / noise >10).
3. At 6% of Nitrogen such TPC is already more efficient for GRNA, than
liquid scintillator detectors.
4. Further study on recombination mechanisms in LAr-N is needed.
5. The technology is very promising for security applications !
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
23
LAR+N TPC Plans and Perspectives
1. More detailed study on recombination vs Nitrogen content with
non-resonant gammas.
2. Study of charge attachment crossection vs Nitrogen content.
3. Proton - electron separation study (simulation)
4. Tests with resonant gammas on the proton accelerator.
5. Optimization of the detector geometry for GRNA scenario.
6. Contacts with industry - building the cargo screener prototype
I.Kreslo
CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.
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