Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of...
-
date post
19-Dec-2015 -
Category
Documents
-
view
238 -
download
2
Transcript of Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of...
![Page 1: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/1.jpg)
Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging
Paul Garrett
University of Guelph
for the DESCANT Collaboration
NEDA collaboration meeting Valencia, November 3-5, 2010
![Page 2: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/2.jpg)
Challenges of studies of n-rich nuclei at RIB facilities
Fusion-evaporation or reaction studies using n-rich beams
• Low-beam currents• The best beams will have 109, and “good” beams will have 106 ions/s
on target – much less than at stable beam facilities
• Backgrounds from scattered beam
• Must be able to characterize evaporation products in regions where little is known
• On neutron-rich side, copious neutron evaporation, charged-particle exit channels suppressed
• Some reactions wont have a sufficiently confined recoil cone for efficient detection in recoil separator
• Want to make use of all available solid angle
• Need for determination of neutron multiplicity
![Page 3: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/3.jpg)
Examples of fusion-evaporation studies
1n gated
2n gated
2n gated with nearest-neighbour rejection
2n gated with nearest-neighbour rejection + TOF analysis
Bentley et al., PRC 73, 024304 (2006).
![Page 4: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/4.jpg)
DESCANT
• 70 irregular hexaconical detectors containing liquid deuterated scintillator; each 15 cm deep
• 5 different shapes in 5 rings to achieve close-packing
• 20 x White Detector
• 10 x Green Detector
• 10 x Yellow Detector
• 15 x Red Detector
• 15 x Blue Detector
![Page 5: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/5.jpg)
DESCANT
• Maximum angle subtended of 65.5o
• 92.6% coverage of available solid angle or 1.08p sr
• Fast neutron tagging from 100’s of keV to ~10 MeV
• Digital signal processing
• Front face 50.0 cm from the centre of the sphere, back face at 65.0 cm
• 4 basic shapes used : White, Red, Blue, Green
• The Green and Yellow detectors are mirror images
![Page 6: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/6.jpg)
The DESCANT Detectors
11.65 cm
14.30 cm 13.45 cm
6.12 cm
5.62 cm
12.83 cm 13.40 cm
12.22 cm
15.14 cm
7.63 cm 4.79 cm
Green is truncated White shape
![Page 7: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/7.jpg)
En = 3.0 MeV
BC537
BC501A
Test results from 10cm diameter, 2.5cm deep cell with monoenergetic neutrons
En = 4.3 MeV
![Page 8: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/8.jpg)
• Received prototype June 2010
• Performed acceptance tests using g-sources and a Pu-Be neutron source
• Measured neutron response function using mono-energetic neutron beam at University of Kentucky
Prototype White Detector
![Page 9: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/9.jpg)
Energy Resolution
• Measured energy resolution using 137Cs, 22Na and 60Co
• Each source placed 30 cm from front face
137Cs60Co
Eres = 25.3% Eres = 25.6%
![Page 10: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/10.jpg)
Time Resolution
• Measured with 60Co source using a fast plastic scintillator
FWHM = 0.97 ns
![Page 11: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/11.jpg)
n– Discrimination• Measured using Pu-Be source placed 1 m from front face
• Zero cross-over timing method
• FWHMn = 54 chn
• FWHMg = 27 chn
• Dchannel = 98 chn
FOM = 1.2
g
n
![Page 12: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/12.jpg)
Other performance tests
• Measured light collection across detector using 137Cs• Source placed directly on the front face at several locations
• Measured effective change in gain due to count rate using 137Cs source• Count rate ranged between 4850 s-1 and 32800 s-1
• Noise level defined to correspond to a count rate of 10 counts s-1 keVee-1
C / C ~ 1.5%
C / C ~ 1.9%
Noise Level = 17.3 keVee
![Page 13: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/13.jpg)
Mounting of DESCANT to TIGRESS
• Support shell (nearly) monolithic – all detectors can be mounted into support shell from rear
![Page 14: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/14.jpg)
Mounting of DESCANT detectors
![Page 15: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/15.jpg)
DESCANT layout – option 1
• 70 element array• 8.9 cm radius opening
for beam tube
![Page 16: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/16.jpg)
DESCANT layout – option 2
• 65 element array• 24.3 cm radius
opening for beam tube or auxiliaries
![Page 17: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/17.jpg)
DESCANT layout – option 3
• 55 element array• 44.2 cm radius
opening for beam tube or auxiliaries
![Page 18: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/18.jpg)
TIG-4G Readout
• Readout of DESCANT detectors by custom built 12- bit 1GHz digitizers built to “TIG” standard
• Anode pulse direct to TIG-4G via low-loss cable (LMR400)
• On-board pulse-height, event time, and n-g discrimination determination
• TIF-4G will be able to trigger DAQ
![Page 19: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/19.jpg)
DSP for n-g determination
c
tbt
at
CeBeAeNtL
![Page 20: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/20.jpg)
Real waveform analysis with 1GS/s
g events
g+n events
B/A
![Page 21: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/21.jpg)
• Timeline• Prototype TIG-4G – Nov. 2010
• First production DESCANT detectors – Jan. 2011
• Delivery of 72 units – Sept. 2011
• Frame construction – Spring 2012
• Commissioning with 18O+13C reaction – late Spring/early summer 2012
• Funding • Canadian Foundation for Innovation – $665k
• Ontario Research Fund – $665k
• TRIUMF – frame design/construction ~ $370k
• Costs • 72 BC537-filled detectors from St. Gobain – $880k
• 18 modules TIG-4G – $130k
• 2xVME64x crates, CAEN HV supplies, cables/connectors, misc. – $150k
![Page 22: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/22.jpg)
DESCANT Collaboration
• University of Guelph• TRIUMF• University of Montreal: J. P. Martin• University of Kentucky: S. W. Yates, M. T.
McEllistrem• Colorado School of Mines: F. Sarazin
![Page 23: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/23.jpg)
![Page 24: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/24.jpg)
![Page 25: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/25.jpg)
Example: fusion evaporation
• Use the most n-rich beam available on a light target
• Why a light target (i.e. C)?• The radioactive beams off a UC target are more n-rich than the fused systems
• Heavier targets require more beam energy to get over Coulomb barrier – more neutron evaporation from final system so can’t get as neutron rich
• C has good physical properties, easy and cheap to fabricate
• Simple count rate estimate:
• Nc=egetagNtNbs
• Lets assume a 1 mg/cm2 13C target Maybe we can think about a 14C target
• With eg=0.2 and etag=0.2, and count rate of 1 min-1
Nbs = 0.9×104 b/s
• For a 10 mb cross section, we need ~1×106 ion/s• must have at least 109 yield in target (1010 better)
• Calculations of neutron-rich beams assuming a 20 g/cm2 U target and 40 mA of proton beam
• ALICE calculations of cross sections
![Page 26: Progress on DESCANT DEuterated SCintillator Array for Neutron Tagging Paul Garrett University of Guelph for the DESCANT Collaboration NEDA collaboration.](https://reader035.fdocuments.net/reader035/viewer/2022062516/56649d2d5503460f94a03c0a/html5/thumbnails/26.jpg)
Limits
Black line = limit of observation with a production yield of 109 in the U target, a 13C target, and at least 1 mb X-sec.
Highlighted squares represent the highest-mass stable isotope.
No attention paid to feasibility of producing required beams