Development of Liquid Nitrogen Time Projection Chambers

1. Development of Liquid Nitrogen Time Projection Chambers A. Ereditato, M. Hess, S. Janoŝ, 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 I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

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) I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

3. Gamma Nuclear Resonant Absorption method of Nitrogen detection (Soreq NRC, 1985) 9.17 MeVγ ~1.5 MeV 14N 13C p I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

4. e- e- e- e- e- Gamma Nuclear Resonant Absorption method of Nitrogen detection (Proposed by Soreq NRC* to US FAA in 1985) Detector Intensity Non-Resonant γ Resonant γ 14N 13C p 14N e- N content e- * Sorec National Research Center, Yavne, 81800, Israel I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

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 ? I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

6. Ionisation signals in Liquid Argon - Nitrogen Plans and Perspectives I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

7. Charge transport in Liquid Argon - Nitrogen I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

8. Electron mobility in Liquid Argon - Nitrogen Detector scheme I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

9. LAR TPC prototype Mixture LAr-LN is prepared directly in the 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.

10. LAR TPC prototype Wire pitch 2 mm HV power supply 0-30kV 100 x 100 mm To preamp 8mm I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

11. 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, Hofgut, 3073 Gumligen , Switzerland I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

12. 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.

13. LAR TPC prototype and performance Muon 0-30 kV I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

14. 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.

15. LAr TPC prototype and performance TPC response to a primary ionization Primary ionisation Q0 Recombination losses q0=A*Q0 Attachment losses q=q0e -(D/λ) Particle E collection wires I- Ar+ e- I- I- Ar+ e- e- D, drift distance I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

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. I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

17. 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.

18. 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.

19. 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.

20. 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.

21. LAR+N TPC prototype and performance Recombination vs Nitrogen content, (vol. %) A~0.5 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 ! A=1 I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

22. A Betha LAR+N TPC prototype and performance Box model parameters evolution with LN content (vol. %) I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

23. LAR+N 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 >10). • 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 ! I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.

24. LAR+N 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 I.Kreslo CHIPP workshop on Detector R&D, University of Geneva, 11-12 June 2008.