Nebraska’s Statewide Outreach and Education Experiment

The Cosmic Ray Observatory Project

Dan ClaesUniversity of Nebraska-Lincoln

Washington Area Large Time-coincidence Array

SALTA Schoolsand the

Henderson Mine ProjectThursday, October 14, 2004

CROP article in Lincoln Journal Star, 7 August 2003

The Chicago Air Shower ArrayThe Chicago Air Shower Array

•Located in the Utah Desert•1089 stations, 15m spacing•covering 0.23 square km

each houses 4 scintillators w/tubes1 high and 1 low voltage supply

CROP/ WALTA/ SALTA recycle detectors from the Chicago Air Shower Array

U.S. Army PhotoSeptember 30,

1999

The CROP team at Chicago Air Shower Array (CASA) site

CASA detectors’ new home at the University of Nebraska

2000 scintillator panels, 2000 PMTs, 500 low and power supplies at UNL

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

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950 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

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•EMI Photomultiplier tubes are working

•Typical efficiency of counters 85% - 95%

CROP Workshops

Oscilloscope

training

Tearingthe oldCASA

counters apart

Scraping, sanding and polishing

Wrapping & light-tighting

Electronics lessons

• LabView (PC)

• At-a-glance monitoring of incoming data

•Graham Wheel (UWash) Jared Kite (UNL)

Monitoring Program for Data Acquisition Card

Cosmic Ray Observatory Project

Collecting Data with CROP DAQ Card Interface

Doing an Efficiency Scan

1. Disconnect the 4 signal cables from the DAQ card. These are the cables that connect to your 4 detectors.2. Open the CROP_DAQ LabVIEW Program.

3. Click on the "Efficiency" tab make sure the Efficiency Scan button is ON(lit up).

4.  Click on the "Threshold Scan" tab make sure the Threshold Scan button is OFF.

5. Click on the "Data Collection Settings" tab and set the timer ON (green button lit up).

6.  Click on the "Data Acquisition" tab and to begin run click on  (upper left corner under the Edit menu).

http://crop.unl.edu/tutorials/Online help and tutorials available.

On-Line Oscilloscope Cheat Sheets

http://unlhep2.unl.edu/~CROP/oscihomepage.html

April 2001 participant meeting at UNL

Marian High Schoolstudents presenting

results and discussingcosmic rays withProf. Jim Cronin,

University of Chicago

Barometric Pressure (mmHg)

727 747

4-F

old

Coi

nci

den

ces

/ 2 h

ours

3000

4200

• Statistical error bars shown• 1.3% decrease per mmHg

Marian High School’s Measurement of Cosmic Ray Rate vs. Barometric Pressure

http://marian.creighton.edu/~besser/physics/barometer.html

Mount Michael Benedictine High School

“The Science Teacher”, November 2001

The Washington-Area Large-ScaleTime-Coincidence Array

http://www.phys.washington.edu/~waltahttp://www.phys.washington.edu/~walta

Seattle area map showing schools

• CROP’s closest relative

• University of Washington, Seattle Jeff Wilkes, et al.

• also using refurbished CASA detectors

• WALTA/CROP/FNAL collaboration developing DAQ PC electronics card

• Funding limited, but used QuarkNet association to fund 1st WALTA workshop, August 2001

WALTA/QuarkNet One-week Summer Workshop

University of WashingtonAugust 2001

Seattle teachers and WALTA staff Refurbishing 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. -- 10,152 feet above sea level

SALTA: Snowmass Area Large Time-Coincidence Array

Empire

• Clear Creek High School, Empire, CO

Leadville1

10 miles

Polishing scintillatoredges outside

Conference Center

Making detectors light-tight

SALTA Workshop, July 2001, Snowmass, CO

massphototube

gluing

Henderson Mine Visit

Dec 4, 2003hosted by

Chip deWolfe

Marc Whitley Diana Kruis Nancy Spletzer Aspen High School Basalt High School Clear Creek High School

Michelle Ernzen Laura FrenchLake County School Roaring Fork Valley

Hans-Gerd BernsUniversity of Washington

Dan ClaesUniversity of Nebraska

Scouted 3 possible locationsbetween 2800-3900 ft depths

110 power available

•Can't survey the proposed site, but plan to 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.

4 sites have been identified ranging from 3000 – 4000 overburden

January 13-15 – Claes visits the SALTA schools to check out condition of detectors and meet with students

Cosmic Ray Scintillator TestingThreshold Testing Results

Online exponential fit program: http://cms.dt.uh.edu/Faculty/BecerraL/ExpFit.htm

Results posted by students from Basalt High School

Threshold(mv) Hits per minute

20 263885

30 220347

40 133871

50 94560

60 54108

70 66733

80 31927

90 25696

100 8011

Scintillator Two

f(x) = 480410.6452 (.9682754831^x)Coefficient of correlation: .9488743319

A Threshold ScanRather 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 10-15 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:

Aspen Center for Physics July, 2004: Back for MORE!

Aspen Center for Physics Education & Outreach WorkshopJuly 6-8 SALTA schools take over the library, setting up cosmic ray telescopes, for training in the new DAQcard

that will be used in all their data-taking.

¼ in lead

Detectors•telescoped pair with coincidence requirement against noise•sandwiched with lead sheet

have been reconfigured into muon telescopes

•At mining level (3000 mwe) the rate for any single (2 ft 2 ft) panel will be low

•We take two such modules down into the mine

•May need week(s) long runs

We are moving the detectors at 2-3 week intervals

with dust a problem for a PCwe house a low-power serial digital data logger

A portable stand holds each muon telescopes.

Desktop Base StationAn ~identical pair of modules are running in a fixedlocation (surface office) to establish our baseline

where dust may be a problem for a PC

we house the low-power serial digital data loggeralongside the DAQcard

thanks to Hans Berns’ initial testing withAcumen Instruments Databridge

development kit

SALTA’s Henderson Project is launched September 29, 2004

Clear CreekHigh School

studentsset up thesatellitemodules

1st undergroundrun started

2:12pm9/28/04

8100Electrical

Shop

Clear CreekHigh School

instructorNancy Spletzer

does the Honors

Punching the RUN

button

The future

At the conclusion of Henderson measurements• revive the original cosmic ray grid plans for SALTA

• work with schools to plug into CROP-WALTA

• recruit neighboring schools to expand the grid

Wherever/whenever the UNO facility is built

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, their data will be part of the CROP-WALTA network.

a cosmic ray grid on area schoolswill continuously monitor

the local cosmic "weather"reporting it as close to live

as we can to the lab.