Nebraska’s Statewide Outreach and Education Experiment The Cosmic Ray Observatory Project Dan Claes CROP Spring 2004 Workshop Saturday, May 1, 2004 Washington Area Large Time-coincidence Array Henderson Mine: Cosmic Ray Flux Measurements Status Report

WALTA/QuarkNet One-week Summer Workshop University of Washington August 2001 Seattle teachers and WALTA staffRefurbishing CASA scintillators

Aspen High School, Aspen, CO Basalt High School, Basalt, CO Roaring Fork Valley High School, Carbondale, CO Lake County High School, Leadville, CO The highest-elevation school in U.S ,152 feet above sea level SALTA: Snowmass Area Large Time-Coincidence Array Empire Clear Creek High School, Empire, CO

Polishing scintillator edges outside Conference Center Making detectors light-tight SALTA Workshop, July 2001, Snowmass, CO mass phototube gluing

Underground Neutrino Observatory The proposed next-generation underground water Čerenkov detector to probe physics beyond the sensitivity of the highly successful Super-Kamiokande detector in Japan

The detector is located 1 kilometer below Mt. Ikenoyama inside the Kamioka zinc mine. Super-Kamiokande located in the Japanese alps near the town of Kamioka

The SuperK detector is a water Čerenkov detector 40 m tall 40 m diameter stainless steel cylinder containing 50,000 metric tons of ultra pure water

The main sensitive region is 36 m high, 34 m in dia viewed by 11,146 inward facing Hamamatsu photomultiplier tubes surrounding 32.5 ktons of water

Super K inner chamber ~half-filled

Underground Neutrino Observatory 650 kilotons active volume: 440 kilotons 20 times larger than Super-Kamiokande major components: photomultiplier tubes, excavation, water purification system. $500M The optimal detector depth to perform the full proposed scientific program of UNO  4000 meters-water-equivalent or deeper

searching for the long-sought-after decay of the proton and engaging in a rich study of neutrinos from a broad range of sources accelerator beams supernovae as far away as the Andromeda galaxy supernova relic neutrinos atmospheric neutrinos solar neutrinos. If realized, a next-generation underground detector could result in great discoveries with far reaching impact on astrophysics, nuclear physics and particle physics, for decades to come. UNO will serve as a multi-purpose laboratory

HEPAP is a federal advisory committee chartered by the Department of Energy (DOE) reporting directly to its Director of the Office of Science. HEPAP periodically reviews the national high energy program, evaluating competing long-range plans, prioritizing projects, advising the NSF and DOE on levels of funding, and the High Energy scientific community on strategies. Feb. 2003: HEPAP Facilities Committee convened chaired by Fred Gilman, Carnegie Mellon University Charged by Dr. Ray Orbach (Director, DOE Office of Science) to review 12 possible future projects w/ >$50M project cost

The final Committee Report ranked the scientific potential of UNO as Absolutely Central

U.S. sites being considered: the Henderson (Colorado), Homestake (Lead, SD) and Soudan (Minn) mines, the San Jacinto Mountain (CA) and the Waste Isolation Pilot Plant, WIPP (New Mexico).

Leadville 1 10 miles

Henderson Mine Visit Dec 4, 2003 hosted by Chip deWolfe Marc Whitley Diana Kruis Nancy Spletzer Aspen High School Basalt High School Clear Creek High School Michelle Ernzen Laura French Lake County School Roaring Fork Valley Hans-Gerd Berns University of Washington Dan Claes University of Nebraska

Scouted 3 possible locations between ft depths 110 power available

Issues: Can't survey the proposed site, but can use spots away from glory hole ( where blasting still common & overhead rock broken up ) Topological graphs and CAD tools can provide good estimates of overburden at survey-able spots. where dust may be a problem for a PC can house a low-power serial digital data logger Hans Berns experimenting with Acumen Instruments Databridge development kit

January – Claes visits SALTA schools to check out detectors, meet with students and review DAQcard operations

Four analog PMT inputs PC serial port GPS input Event counter Programmable logic device CROP data acquisition electronics card Developed by Fermilab (Quarknet), Univ. Washington, Univ. Nebraska 50 Mhz (20 nsec) clock interpolates between 1 pps GPS ticks for trigger TDC’s give relative times of 4 inputs with 75 psec resolution Discriminator threshold adjust Assembly/testing by FNAL engineers is done gratis – but at low priority We have had only 2 cards to share among the SALTA schools Time-to-digital converters 5 Volt DC power

SALTA visit just preceded finals week followed by semester break February brought many conflicts good students also very active in many extracurricular activities March brought Spring break! Then April brought PROM …

Cosmic Ray Scintillator Testing Threshold Testing Results Online exponential fit program: Results posted by students from Basalt High School Threshold(mv)Hits per minute Scintillator Two f(x) = ( ^ x ) Coefficient of correlation:

A Threshold Scan Rather than focussing on a single fit to the entire range of data, recognize that two different physics processes are at play. Both generate counts, but with rates that drop off differently with increasing threshold.(Both drop ~exponentially, which is why we use a logarithmic plot). At LOW THRESHOLD we expect to be dominated by noise, which plummets rapidly with threshold. Its exponential drop should ideally look like a straight line on a logarithmic plot. At HIGH THRESHOLD the background noise should be pretty much eliminated, and any additional increase in threshold will actually start cutting into the real signal. Real signals are, on average, larger, so the drop is less severe. This defines two regions with relatively flat (linear) response. Because of the statistical fluctuates common in random events like noise or cosmic ray counts, how straight the lines are may depend on how long you ran at each data point (at least minutes should be OK). Of course the two regions overlap, so there's a middle region that curves. But we can focus on the first few… points at each extreme to determine our linear fits, as I have done (by eye) above. We use the intersection of the two lines to select the threshold (which looks to be about 65 mV in the example above to me). It's a nice to try and confirm your selection by eye. Recall you can set trigger threshold on the oscilloscope. A very low threshold will have the oscilloscope almost continuously triggering, revealing a band of noise (see above). Moving the threshold just far enough to kill the noise and give only the flickering images of healthy signals can give you an approximate idea of where the threshold should be set. See if you can confirm this sort of behavior for the setting your scans suggest you use. Recall the DAQ card has a built-in x2 amplifier, so uses thresholds twice the size of the ones you'll need for the oscilloscope trigger (i.e., a threshold of 65mV from the DAQcard scan corresponds to a 32mV trigger threshold on the oscilloscope). Example of follow-up discussion posted in response:

PMMA (polymethyl methacrylate) doped with a scintillating fluor Read out by 10 stage EMI 9256 photomultiplier tube Recycling material inherited from The Chicago Air Shower Array 2 ft x 2 ft x ½ inch

¼ in lead Detectors telescoped pair with coincidence requirement against noise sandwiched with lead sheet Configuration being explored at UNL and UWash A second ~identical detector will run in a fixed location (surface office) to establish a baseline At mining level (3000 mwe) any one (2 ft  2 ft) panel can be expected to count only a handful of events / day will want to gang several together to increase total area May need week(s) long runs All the SALTA schools are eager to participate! Henderson may be comfortable with 2-week intervals

- S. Miyake et al, Nuovo Cim., 32, 1505 (1964) COR - P.H.Barret et al, Rev. Mod. Phys., 24, 133 (1952)  - L.M.Bollinger, PhD Thesis, Cornell University (1952) - J.Clay and A. von Gemert, Physica, 6, 497 (1939) - J.C.Barton et al, Phil. Mag., 6, 1271 (1961) OR – C.A.Randal and W.E.Hazen, Phys. Rev., 81, 144 (1951) – B.V.Sreekantan and S.Naranan, Proc. Ind. Acad. Sci., 36, 97 (1952) M - Y. Miyazaki, Phys. Rev., 76, 1733 (1949)  - V.C.Wilson, Phys. Rev., 53, 337 (1938) 8400 meters water equivalent Kolar Gold Field zero counts in 2 months (Miyake 1964)

Timeline: September 27 - SALTA teams re-trained at UNL’s Fall Saturday workshop (travel expenses and stipends covered by SALTA/CROP funds) December 4 - retrieved NIM crates (on loan from FNAL-PREP) - Henderson Mine meeting with Chip deWolfe - Claes, Berns, all SALTA teachers January – Claes visits SALTA schools to check out detectors and meet with students March-April – began characterizing SALTA detectors: efficiency, threshold settings July-August – finalize detector configurations – Claes visits SALTA teachers, students for final DAQ training September – finish efficiency, threshold settings – orientation at Henderson Mine for all SALTA participants October - December – data collection student interest remains high (they are plain excited about visiting the mine!) January ′05 student report of measurements at UNO collaboration meeting Note:Students (over 14) will be allowed. Safety escorts required for every access.

Wherever/whenever the UNO facility is built a cosmic ray grid on area schools will continuously monitor the local cosmic "weather" reporting it as close to live as we can to the lab. The future At the conclusion of the Henderson measurements revive original cosmic ray grid plans for SALTA work with schools to plug into CROP-WALTA I hope to see monitors at the lab entrance (and/or visitor’s center) featuring the high school report, so again local schools can feel they are making a contribution to the experiment. At the same time of course, their data will be part of the CROP-WALTA network.