Speaker
Dr
Mohamad Moukaddam
(TRIUMF)
Description
A new ancillary detector, SPICE (SPectrometer for Internal Conversion Electrons) has been constructed and tested for the first time at the
ISAC-II facility of TRIUMF. SPICE is designed to be coupled with the TIGRESS HPGe array to enable simultaneous in-beam gamma-ray and
conversion-electron spectroscopy in both stable and radioactive ion beam experiments. The TIGRESS+SPICE setup will combine with other
downstream detectors/arrays to provide the possibility for a broad range of reaction mechanisms, such as Coulomb-excitation or fusion
evaporation, to be used to populate states of interest.
The main focus of the SPICE design is the reduction of background due to low-energy particles
and beam scattering, a high detection efficiency for electrons and a large energy-acceptance
range between ~100 and 3500$\,$keV. This is achieved using a magnetic lens formed of permanent
NdFeB magnets positioned upstream of the target and surrounding a truncated-conical-shaped
high-Z-material photon shield. The internal conversion electrons emitted from the target are
guided around the photon shield and detected by a large-area annular lithium-drifted silicon
detector which is segmented into 120 individual segments. Reactions induced by a stable 12C beam
at 67$\,$MeV impinging on a 3$\,$mg/cm$^2$ $^{196}$Pt target was studied with SPICE to demonstrate its capacity
of detecting internal-conversion electrons in coincidence with gamma rays in TIGRESS.
The residual $^{12}$C particles were detected with a double-sided annular silicon detector positioned at forward angles.
A selective recoil-electron-gamma-type triggering for enhancing the signal-to-noise ratio of measurements was made possible by integrating the SPICE detector signals into the TIGRESS data-acquisition system.
In the future, SPICE will be a powerful tool to measure conversion coefficients
and $E0$ transitions in atomic nuclei thus providing a useful probe to study shape coexistence and quantum state mixing.
An overview of the main features of the design and results from the test beam-time of SPICE will be presented as well as a look at future opportunities.
Authors
Co-authors
Dr
Alejandra Diaz Varela
(Guelph)
Mr
Alex Laffoley
(Guelph)
Mr
Andrew Finlay
(Guelph)
Mr
Andrew Knapton
(Surrey)
Mr
Badamsambuu Jigmeddorj
(Guelph)
Dr
Baharak Hadinia
(Guelph)
Dr
Carl Svensson
(Guelph)
Dr
Carl Unsworth
(TRIUMF)
Mr
Chris Bolton
(TRIUMF)
Prof.
Corina Andreoiu
(SFU)
Dr
David Miller
(TRIUMF)
Mr
Deng Gatjeng
(Guelph)
Mr
Evan Rand
(Guelph)
Dr
Gordon Ball
(TRIUMF)
Mr
Greg Demand
(Guelph)
Dr
Greg Hackman
(TRIUMF)
Mr
James Wong
(Guelph)
Dr
Leonid Kurchaninov
(TRIUMF)
Mr
Miles Constable
(TRIUMF)
Dr
Mustafa M. Rajabali
(TRIUMF)
Dr
P. C. Bender
(TRIUMF)
Dr
Philip J. Voss
(TRIUMF)
Dr
Reiner Krueken
(TRIUMF)
Dr
Robert Henderson
(TRIUMF)
Mr
Ryan Dunlop
(Guelph)
Dr
Steffen Ketelhut
(TRIUMF)
Dr
William j. Mills
(TRIUMF)
Dr
Wolfram Korten
(CEA)
