Cosmic ray shielding at no v a
1 / 15

Cosmic Ray Shielding at NO v A - PowerPoint PPT Presentation

  • Uploaded on

Cosmic Ray Shielding at NO v A. Travis Olson Krissie Nosbisch. Abstract.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Cosmic Ray Shielding at NO v A' - paxton

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Cosmic ray shielding at no v a

Cosmic Ray Shielding at NOvA

Travis Olson



We used a muon telescope to calculate the cosmic ray background at the NOvA site and determine how effective the barite and other rock around the detector were at shielding. The cosmic ray flux was found to be 0.0053 ± 7.1x10-5muons cm-2sr-1s-1 under the barite which is 29 ± 1.4% less than the flux outside. The rate of electromagnetic showers is 0.0028 ± .0006 showers per second which is 77 ± 5.3% less than the rate outside.

Muon telescope design

Top view of the box showing the garbage bags and duct tape for light-proofing.

High voltage and signal cables

Photomultiplier tube with mirrored base

Plastic scintillator

White reflective cloth

Muon Telescope Design


56.6 cm

  • Muon telescope pieces (left), schematic (center) and full stack (right)

Muon telescope specifications
Muon for light-proofing. Telescope Specifications

  • The telescope has an acceptance of 88.4 ± .36 cm2sr when the boxes are stacked on top of each other.

  • The stack of boxes has a column depth of 4.8 g/cm2 which makes an energy threshold of 35.05 MeV.

  • The plastic scintillator has dimensions of 45.72 ± .05cm x 45.72 ± .05cm x 1.91 ± .05cm and was originally purchased for the Soudan1 experiment.

  • The photomultiplier tubes are 5” PMTs that were originally bought for the HPW experiment.

Daq card
DAQ Card for light-proofing.

  • We used a Quarknet board version 2.0 to record the data.

Daq card settings 1
DAQ Card Settings for light-proofing.1

  • For flux measurements the coincidence window was set to 144 ns and data was recorded for 240ns after the first event in a coincidence.

  • For the electromagnetic shower measurement the coincidence window was set to 1.2 μs and data was recorded for 3.6 μs after the first event.

  • Both measurements required a four way coincidence.

  • Times were chosen to allow coincidences to occur even if there were long cable delays, and as noted later the rate of accidental coincidences is small enough that it won’t play a role even with larger windows.

Optimization tests
Optimization tests for light-proofing.

  • Tests were done to find the optimum operating and threshold voltages.

Location of measurements inside no v a hall
Location of Measurements inside for light-proofing.NOvA Hall

Location of measurement outside no v a building
Location of Measurement outside for light-proofing.NOvA Building

Tilted telescope
Tilted Telescope for light-proofing.

Flux data
Flux Data for light-proofing.

Electromagnetic shower data
Electromagnetic Shower Data for light-proofing.

Conclusions for light-proofing.

  • North and middle flux reduced by 29 ± 1.4%.

  • South flux reduced by 67 ± .8%.

  • Electromagnetic showers reduced by 77 ± 5.3%.

References for light-proofing.

  • Hansen, S.; Jordan, T.; Kiper, T.; Claes, D.; Snow, G.; Berns, H.; Burnett, T.H.; Gran, R.; Wilkes, R.J.; , 2“ Low-cost data acquisition card for school-network cosmic ray detectors," Nuclear Science, IEEE Transactions on , vol.51, no.3, pp. 926- 930, June 2004doi: 10.1109/TNS.2004.829447URL:

  • Rossi, Bruno. "Interpretation of Cosmic Ray Phenomena." Reviews of Modern Physics, vol.20, no.3 1948 doi: 10.1103/RevModPhys.20.537 URL: