1 / 10

Detector and Measurement Interests for n_TOF EAR2

Detector and Measurement Interests for n_TOF EAR2. J. Billowes, C. Guerrero, D. Jenkins, M. Vermeulen , T. Ware, T. Wright. Motivating Measurement: 13 C(n,  ) 14 C.

ide
Download Presentation

Detector and Measurement Interests for n_TOF EAR2

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Detector and Measurement Interests for n_TOF EAR2 J. Billowes, C. Guerrero, D. Jenkins, M. Vermeulen, T. Ware, T. Wright

  2. Motivating Measurement: 13C(n,)14C • Reaction is of great UK interest due to large volume of reactor graphite (130,000 tonnes) from earlier Magnox reactors.14C is a major activation product requiring consideration in decommissioning • Contribution from 13C(n,)14C is source of uncertainty due to low cross section, based on theory • Major issue with measurement is very low capture / scattering ratio (order of 10-3) • High quality sample and new measurement/analysis techniques needed

  3. 13C(n,)14C Other libraries; EAF-2007, EAF-2010, RUSFOND-2010 = JEFF-3.0/A

  4. Contributions to New Detector Arrays • Manchester/York are assembling a EPSRC nuclear data proposal to include detector characterisation work • York have submitted proposal to UK NDA (nuclear decommissioning authority) for studentship to investigate 13C(n,)14C measurement, including detector characterisation • Manchester have facilities and expertise for design and construction of detector assemblies (e.g. TAC array) • York are heavily involved in the PARIS collaboration – which aims to build a calorimeter for SPIRAL2 using lanthanum bromide • York also involved in the NuPNET scheme, GANAS which is characterising novel scintillators and photosensors

  5. Possible detection techniques for 13C(n,g) • Exploit the high gamma-ray sum energy (~ 8 MeV) released from 13C(n,g) in order to discriminate the capture channel • Use novel scintillators like LaBr3or CeBr3. No need for 4πsolid angle but need absolute detector efficiency (from simulations) • Could combine with a C6D6 measurement (for cross section), using the spectroscopy measurement to gain reaction selectivity (no clear idea how to combine the two methods) • Investigate scintillators with high energy resolution and neutron-gamma discrimination e.g. CLYC from Hilger Crystals/RMD • Pair spectrometer – i.e. detect positron/electron pairs from the high energy capture events

  6. Testing with 13C(n,)14C ‘Surrogate’ • 12C(n,)13C cross section is similar to 13C(n,)14C • Could use existing 12C background measurements to test discrimination techniques

  7. Detection Techniques • Discriminate on deposited energy in TAC?

  8. Lanthanum bromide • Very high energy resolution – 3% at 662-keV • York is member of PARIS • PARIS has 28 phoswich detectors (2” cubic LaBr3 + CsI) • Intention is to build full calorimeter of 200

  9. Other new materials might be of interest for neutron-gamma discrimination e.g. CLYC

  10. Pair spectrometer • Pair spectrometers can measure positron-electron pairs from internal pair transitions e.g. 8 MeV transition in 14C following capture • A low probability process (10-3 per decay) • But, in principle, 100% clean as pairs can be moved away from the target avoiding neutron scattering effect • What is plausible efficiency though? – could be less than a % which would make it a very selective but very low overall efficiency technique • Needs modelling

More Related