The Cosmic Ray Observatory Project (CROP)Gregory R. Snow

University of Nebraska / USA

CRSP MeetingNIKHEF, Amsterdam

March 7, 2005

• Overview• Staff and school participants • Classroom and lab training sessions• Hardware, software, analysis status• NATLA, consortium of US efforts• Some lessons learned

First, where is Nebraska?

State of Nebraska

Pierre Augernorthern

hemispheresite in Utah or

Colorado

FermilabBatavia, Illinois

University of Nebraska, Lincoln

One-slide overview

• CROP is in its 5th year of operation

• Funded by a $1.34 Million grant, U.S. National Science Foundation

• Managed by a small team at the Univ. of Nebraska

• 26 participating schools, about 5 new schools added per year

• 4-week summer training workshops and 2 academic year meetings

• Hardware and software• 6060 cm2 scintillators, PMTs, high voltage supplies from

the now-complete Chicago Air Shower Array• Data acquisition electronics card developed jointly with

Fermilab and QuarkNet• LabView control and monitoring program runs on PC at school• Inter-school data analysis starting, development underway

CROP Personnel at Univ. of Nebraska

CROP staff at University of Nebraska• Faculty: Dan Claes and Greg Snow• Educational evaluator: Dr. Duane Shell• Physics graduate student: Xiaoshu Xu

• Undergraduate research assistants: L. Burk, M. Everett, J. Keller, L. Neukirch, Y. Qin• Administrative Secretary: Marilyn McDowell• Lab manager: High school teacher, John Rogers

CROP has employed a steady stream of graduate and undergraduatestudents from Physics, Computer Science, and Science Education, including high school participants who have come to the University to majorin Physics or Engineering.

Undergraduate Physics majors have entered graduate school in Experimental Physics based on the experiences in CROP.

Summer 2004

CROP article in Lincoln Journal Star, 7 August 2003

Colored squares are participating schools

700 km

The Science of CROP

• Each school records building-sized showers -- plenty of rate.• 2500 ft2 shower (1014 eV )

• Neighboring schools in same city (Lincoln, Omaha) see coincidences from highest-energy showers -- low rate.

• 10 sq.mi shower ~1019 eV• 50 sq.mi shower ~1020 eV

• Nebraska is 450 x 250 square miles -- schools separated by very large distances explore whether showers come in large, correlated bursts

That is, does the whole state of Nebraska ever “light up”?

November 2004 One-day Participant Meeting

Teachers and students from about half of CROP’s schools, all yearsTypical school team: 1-2 physics teachers, 3-4 students

The Chicago Air Shower ArrayThe Chicago Air Shower Array

• CROP uses retired detectors from the Chicago Air Shower Array• 1089 boxes each with:

• 4 scintillators and photomultiplier tubes (PMT)• 1 high voltage and 1 low voltage power supply

• Two removal trips (September 1999, May 2001) yielded over 2000 scintillator panels, 2000 PMTs, 500 low and power supplies• Sufficient hardware for all Nebraska high schools

U.S. Army PhotoSeptember 30,

1999

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

Equipment recovery trip to Dugway, Utah, May 2001

Lab Curriculum• Polishing, cleaning scintillator• Gluing PMT and wrapping scintillator• Assembling high-voltage supply• Oscilloscope lesson• Turning on counters, source tests, finding/fixing light leaks• Measure counter efficiency, high voltage plateau

Class Curriculum• History of cosmic rays• Interaction of charged particles with matter• Scintillators and photomultiplier tubes• Cosmic ray energy spectrum• Julian calendar, UTM, galactic coordinates• Global positioning system• Ionizing particle detectors• Calorimeters and showering• Particle zoo and the Standard Model• Tour of high-energy particle accelerators• Random events, probability• Monte Carlo simulations• Lightning protection

Curriculum Topics

Available

What we accomplishin 4 weeks

Preparingdetectors totake to the

schools,experimentaltechniques

Learningthe physicsof cosmicrays andparticle

detectors

Photomultiplier Tubes

Schematic drawing of a photomultiplier tube

Photons eject electrons via photoelectric effect

Photocathode

Each incidentelectron ejectsabout 4 newelectrons at eachdynode stage

Vacuum inside tube

“Multiplied” signalcomes out here

An applied voltagedifference betweendynodes makeselectrons acceleratefrom stage to stage

Incident light from scintillator

Summer 2004 Workshop ActivitiesDetector assembly and testing

Summer Workshop ActivitiesAttaching phototubes

Summer 2004 Workshop ActivitiesOscilloscope and DAQ card lessons

Summer 2004 Workshop ActivitiesPractice experiments to be performed at school

Summer 2004 Workshop ActivitiesDetectors return to school

Detectors in a verticaltelescope

Mini-experiments

• Coincidence rate vs. barometric pressure• Day-night variation of cosmic ray rate• Coincidence rate vs. angle of incidence• Coincidence rate vs. vertical separation

Electronics Configuration for Telescope

Detector set-ups at schools

Telescope set-ups forindoor experiments

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

ncid

ence

s / 2

hou

rs

3000

4200

• Statistical error bars shown• 1.3% decrease per mmHg

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

Mount Michael High School “The Science Teacher”, November 2001

5 VoltDC power

To PCserial port

Four analogPMT inputs

Discriminatorthreshold

adjust

GPS receiverinput

Eventcounter

Programmablelogic device

Time-to-digitalconverters

CROP data acquisition electronics card

Developed by Univ. Nebraska, Fermilab (Quarknet), Univ. Washington

• 43 Mhz (24 nsec) clock interpolates between 1 pps GPS ticks for trigger time• TDC’s give relative times of 4 inputs with 75 picosecond resolution

User-friendly, LabView-based control and monitoring GUI

Two detectorsfiring at thesame time

Data streamfor eachevent

Eventcounter

Elapsedrun

time

Labview softwareTabs for different experimental procedures

Simultaneous data-taking at 3 sites in Lincoln

UNL Ferguson Hall

Lincoln High

Zoo School

• Concerted effort to collect data continuously since mid-August 2004• Each school writes data file, collected twice per week.• Analysis file-by-file at UNL• Searching for events occurring at the same time (within a microsecond)

Installation at Lincoln High School, August 2003

GPS receiver

Weigh down cablebundles at various

points

Nice, neat cablebundles fanned out

GPS receiver must be in a weather-tight enclosurewhich is NOT metallic

• We used Tupperware container half-filled with sand

• GPS receiver on top of sand

• Connection to long extension cable INSIDE Tupperware

• Make sure it’s weather-tight

GPS mount at the Spalding Academy

What’s wrong with this picture?

GRID computing being applied to data analysis needs

Web site explains data analysis frameworkSee: http://quarknet.fnal.gov/grid/

Web site explains data analysis frameworkSee: http://quarknet.fnal.gov/grid/

Schools can upload raw data files to server.

Some simple analysis tools in place.Example: search for time coincidences among chosen

schools’ data files.

Univ. of Nebraska Research Computing Facility

Nebraska named Tier 2 computing center for CMS/LHC

Future host of CROP analysis

David SwansonDept. of Computer Science and

Engineering

CROP SCRODSALTA

CHICOS

WALTA ALTA

NALTAThe North American Large-Scale Time-Coincidence

Array

http://csr.phys.ualberta.ca/nalta/• Includes links to individual project Web pages

TECOS

Institutions• LA area schools• California Institute of Technology• California State University, Northridge• University of California, Irvine

Funding• Caltech• NSF Nuclear Physics

Los Angeles Area Schools

(Animation by L.A. school teacher)

• 164 detector stations recovered

• 2 detectors per school foreseen

• About 10 schools in process of being outfitted

Aiming toward a worldwide networkof cosmic ray detectors

Some lessons learned

• Big variation among schools in independent activity/investigations during school year. Some real successes, some inactive sites

• Close contact very important during academic year

• Scheme for replacing/training new students as classes graduate important

• Classroom integration, affect on curriculum is not automatic. Scheme to guide this needed.

• Hardware and software delays create frustration and idleness

• Hard to recruit for long summer workshops

• High school schedules are packed, hard to get full participation in academic year Saturday meetings of all participants