Optical System for Micro Boo NE Arati Prakash

Optical System for Micro. Boo. NE Arati Prakash Massachusetts Institute of Technology Fermi National Accelerator Laboratory

Outline �Introduction - What is Micro. Boo. NE �Light in Liquid Argon �Micro. Boo. NE PMT System Design 2 Arati Prakash INSS 07/20/2011

Outline �Introduction - What is Micro. Boo. NE �Light in Liquid Argon �Micro. Boo. NE PMT System Design 3 Arati Prakash INSS 07/20/2011

Micro. Boo. NE Experiment � 170 ton Liquid Argon Time Projection Chamber (LAr. TPC) � Examine low energy neutrino cross sections �Low energy excess observed in Mini. Boo. NE experiment – or e? � Start taking data early 2014 � Located on axis to the ~1 Ge. V Booster Neutrino Beamline at Fermilab (Chicago, IL) 4 Arati Prakash INSS 07/20/2011

Micro. Boo. NE Detector Design � LAr. TPC: 3 wire planes with 2. 5 m drift in 170 tons of LAr � Located in a cylindrical cryostat vessel: 4 m radius x 12 m length � PMT system sits along the wall behind the TPC �Charge drifts to the TPC planes T~ms �PMT scintillation light detected T ~ns �So, the PMT system in principle can trigger the TPC 5 Arati Prakash INSS 07/20/2011

Outline �Introduction - What is Micro. Boo. NE �Light in Liquid Argon �Micro. Boo. NE PMT System Design 6 Arati Prakash INSS 07/20/2011

LAr Scintillation Light Prompt component: T ~ 6 ns (25%) Excitation Ar* Excited molecule Ar 2* Ar+ Ionization Ar 2+ Ar 2* Ionized molecule Delayed component: T ~1. 6 us (75%) Arati Prakash 128 nm Ar Ar 7 Ar e. Recombination INSS 07/20/2011

Outline �Introduction - What is Micro. Boo. NE �Light in Liquid Argon �Micro. Boo. NE PMT System Design 8 Arati Prakash INSS 07/20/2011

System Requirements �In the Micro. Boo. NE E = 500 V/cm, we expect 24, 000 photons/Me. V �Need to trigger on a 40 Me. V proton (~30 Me. V MIP particles) for Micro. Boo. NE �Further goal: trigger on a 5 Me. V electron to see supernovae events 9 Arati Prakash INSS 07/20/2011

Design Constraints �PMTs must work efficiently at cryogenic temp (87 K) �UV light does not pass through glass - Scintillation light (128 nm) must be made visible to PMTs �Optimize Cost vs. coverage �Maintain LAr purity �Allow enough space for TPC �Longevity of the System 10 Arati Prakash INSS 07/20/2011

Choice of PMT � 30 x 8 -inch, 14 -stage Hamamatsu cryogenic PMT �Gain ~10^9 11 Arati Prakash INSS 07/20/2011

Wavelength shifting � Scintillation light is produced in the UV ~128 nm. � We coat acrylic plates with TPB mixture to shift the light into the visible, ~425 nm. (Previous experiments (ICARUS) coated PMTs directly. ) 12 Arati Prakash INSS 07/20/2011

Conclusion �Micro. Boo. NE will hopefully provide valuable information for LAr. TPC detector R&D, as well as data that will be informative for understanding the Mini. Boo. NE observed excess etc. �Come see my poster! Thank You 13 Arati Prakash INSS 07/20/2011

Micro. Boo. NE People Brookhaven Lab Hucheng Chen Jason Farrell Francesco Lanni David Lissauer Don Makowiecki Joseph Mead Susan Duffin Veljko Radeka Sergio Rescia Jack Sondericker Craig Thorn Bo Yu Kuo-Chen Wu Princeton University Kirk Mc. Donald Changguo Lu Qing He 14 Arati Prakash Columbia University Leslie Camilleri Rachel Carr Gary Cheng Georgia Karagiorgi Camillo Mariani Bill Seligman Mike Shaevitz Bill Willis Bill Sippach Cheng-Yi Chi Los Alamos National Laboratory Gerry Garvey Jackie Gonzales Bill Louis Chris Mauger Geoff Mills Zarko Pavlovic Richard Van de Water Hywel White Fermilab Bruce Baller Cat James Hans Jostlein Stephen Pordes Gina Rameika Jennifer Raaf Tinjun Yang Brian Rebel Rich Schmitt Dave Schmitz Jin-Yuan Wu Sam Zeller Herb Greenlee Mike Kirby Kansas State University Tim Bolton David Mc. Kee Glenn Horton-Smith MIT William Barletta Len Bugel Janet M. Conrad Christina Ignarra Ben Jones Teppei Katori Tess Smidt Arati Prakash Yale Bonnie T. Fleming Eric Church Roxanne Guenette Andrzej Szelc Josh Spitz Kinga Partyka Adam Patch Ellen Klein Joseph Lozier Michigan State University Carl Bromberg Dan Edmunds University of Cincinnati Randy Johnson Saint Mary's University of Minnesota Paul Nienaber University of Texas at Austin Sacha Kopp Karol Lang Syracuse University Mitch Soderberg INSS 07/20/2011