• NPL-Home
  • About Us
  • Accelerators
    • Betatrons
      • Plasma Betatron Coil Form: Design and Construction
      • Pulsed B-Dot Measurement
      • CW B-Dot Measurement
      • First Beam Attempts
    • Cyclotrons
      • 12-Inch Cyclotron
      • Axial Betatron Motion
      • Floating Wire Technique
      • 12-Inch Cyclotron Papers
    • DC Potential Drop
  • Experiments
    • Alpha Spark Detector
    • Diffusion Cloud Chamber
    • Wilson Cloud Chamber
    • Deuterated Target Preparation
    • Gamma-Gamma Coincidence
    • Measurement of excited Np237 half-life via the alpha-gamma coincidence method.
    • MUONS
      • Life & Times of a Muon
    • Neutrons
      • Neutron Detection with He-3
      • Neutron Induced Gamma Rays
      • Neutron Diffusion Time Measurement
    • Photography
      • AVCO Rotating Mirror
      • Dark Room
      • Rotating Drum Camera
      • Schlieren Photography
      • Fast Flash Photography
      • X-Rayted Photos
    • Rutherford Scattering
    • Thermoluminescence
  • High Voltage
    • Blue Thunder – An Electrolytic Cap Bank
    • Jacob’s Ladder
    • Krytrons
    • Marx Generator
    • Electric Watermelon
    • Quarter Crushing
    • Tesla Coils
      • Jay’s Tesla Coil
      • Variacs
  • History
    • Heisenberg Cube
    • The Kerst Collection
    • Koeth Collection – Consumer Products
    • Koeth Collection – Radiation Detection Instruments
    • Koeth Collection – Reactors & Weapons
    • Koeth Collection – Games & Collectables
  • Plasma
    • Fusors
      • FUSOR I
      • FUSOR II
      • Scott’s Fusor
      • Fusor Simulations
    • The Mirror Machine
    • Pinch Machines
      • Linear Pinch
      • Toroidal Pinch
      • Pinching
  • Spectroscopy
    • Alpha Particle Spectroscopy
    • Gamma Ray Spectroscopy
      • HPGe Gamma Ray Spectroscopy Education
      • HPGe Systems
      • Cosmogenic Be-7
      • Trinitite
      • Autunite
      • NAS Wildwood Mystery
      • Tc-99m : Cardiac Stress Test
    • Software & Hardware
      • Amateur Canberra Spectroscopy System
      • Antique MCA
      • DIY Matlab MCA
      • NIM Modules
        • Canberra Nim Modules
        • ORTEC Nim Devices
      • Refurbishment of LN2 Dewars
  • Search Icon

NPL

Nuclear Physics Lab

NPL
Neutron Detection with He-3

Neutron Detection with He-3

Author: Luke, Scott, & Tim

Scott found a good source for 6-inch 4-atm 3He neutron detector tubes a few years back. So we wanted to take one of them and turn it into our standard detector system for making absolute neutron rate measurements of our various neutron producing endeavors. This chronicles the empirical design, construction and calibration of that detector.

Over a decade ago Tim purchased 1500 lbs of pure polyethylene in the form of eight 2-inch thick slabs from a guy in New Mexico. Six of the slabs were cut up into 2x4x8 bricks for convenient stacking, and you will see them in use elsewhere in photos on this site. One slab was left in tact to create a large volume detector someday. That day has arrived.

First, we needed to determine the optimal geometry (other than a cylinder). We empirically accomplished this by stacking the bricks around the side, front and back of the detector to give the highest response from a fix distance 252Cf source (Tim is the custodian of a small calibrated 252Cf source at UMD). Once that geometry was determined we designed the monolithic moderator.

The neutron source near the assembled moderator blocks.
The neutron testing range.
The 2-inch thick slab to be turned into the new detector moderator.
Scott and Luke machined the slab into three plates, and cleverly pinned them together will pure polyethylene dowels – making the moderator pure polyethylene.
The middle plate had a groove milled in it to form the well the 3He tube would sit in.
Now to perform the absolution calibration again the 252Cf standard.
The data.
The data close up.
Our detector in use with the 12-Inch Cyclotron
Our detector in use with the FUSOR-II
Back
  • NPL-Home
    • About Us
    • Accelerators
      • Betatrons
        • Plasma Betatron Coil Form: Design and Construction
        • Pulsed B-Dot Measurement
        • CW B-Dot Measurement
        • First Beam Attempts
      • Cyclotrons
        • 12-Inch Cyclotron
        • Axial Betatron Motion
        • Floating Wire Technique
        • 12-Inch Cyclotron Papers
      • DC Potential Drop
    • Experiments
      • Alpha Spark Detector
      • Jay’s Diffusion Cloud Chamber
      • Tim’s Wilson Cloud Chamber
      • Deuterated Target Preparation
      • Gamma-Gamma Coincidence
      • Measurement of excited Np237 half-life via the alpha-gamma coincidence method.
      • MUONS
        • Life & Times of a Muon
      • Neutrons
        • Neutron Diffusion Time Measurement
        • Neutron Induced Gamma Rays
        • Neutron Detection with He-3
      • Photography
        • AVCO Rotating Mirror
        • Dark Room
        • Fast Flash Photography
        • Rotating Drum Camera
        • Schlieren Photography
        • X-Rayted Photos
      • Rutherford Scattering
      • Thermoluminescence
    • History
      • The Kerst Collection
      • Heisenberg Cube
      • Koeth Collection – Consumer Products
      • Koeth Collection – Radiation Detection Instruments
      • Koeth Collection – Reactors & Weapons
      • Koeth Collection – Games & Collectables
    • High Voltage & Pulsed Power
      • Blue Thunder
      • Jacob’s Ladder
      • Krytrons
      • Marx Generator
      • Electric Watermelon
      • Tesla Coils
        • Jay’s Tesla Coil
        • Variacs
      • Quarter Crushing
    • Plasma
      • Fusors
        • FUSOR I
        • FUSOR II
        • Scott's Fusor
        • Fusor Simulations
      • The Mirror Machine
      • Pinch Machines
        • Linear Pinch
        • Toroidal Pinch
        • Pinching
    • Spectroscopy
      • Alpha Particle Spectroscopy
      • Gamma Ray Spectroscopy
        • HPGe Gamma Ray Spectroscopy Education
        • HPGe Systems
        • Cosmogenic Be-7
        • NAS Wildwood Mystery
        • Autunite
        • Trinitite
        • Tc-99m : Cardiac Stress Test
      • Software & Hardware
        • Refurbishment of LN2 Dewars
        • DIY Matlab MCA
        • Amateur Canberra Spectroscopy System
        • Antique MCA
        • NIM Modules
          • Canberra Nim Modules
          • ORTEC Nim Devices

Categories

Recent Comments

  • Jay on Refurbishment of LN2 Dewars
  • Nitrous on Refurbishment of LN2 Dewars
  • Jay on ORTEC Nim Devices
  • CIP on ORTEC Nim Devices
  • Jim Reardon on ORTEC Nim Devices

Meta

  • Log in
  • Entries feed
  • Comments feed
  • WordPress.org
© 2023   All Rights Reserved.