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ORISS Isomer and Isobar Spectrometer and Separator for

Study of Exotic Decays

A. Piechaczek for the

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EMIS 2007

UNIRIB Consortium

• The purpose is to provide a nuclear research facility at ORNL for consortium members

• Consortium members:

                                                     

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EMIS 2007

• Our Deliverable is Science – Nuclear Physics

• We do research• We give scientific reports at meetings• We train students

• UNIRIB, with ORISE and ORAU, provides a university atmosphere in a national laboratory

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Motivation to build ORISS – Oak Ridge Isomer/Isobar Spectrometer and Separator:

• Decay studies often possible from yield considerations, but limited by background from isobaric/isomeric contamination

• Need high resolution separator for background suppression

ORISS predicted performance:• High mass resolving power, M/∆M up to 400,000 (FWHM)• Almost complete Suppression of neighboring isobar• High efficiency ~ 50%• Chemistry independent• Transportable• Cost effective

… use Multi-pass Time of Flight principle!

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EMIS 2007

Multi-pass Time-of-Flight system: concept

MTOF Spectrometer: Spectrum taken with MCP

MTOF Separator: Physical separation using fast electrostatic gate (Bradbury Nielsen gate)

DToF = ½ ToF DM/M

Pulsedion source

MCP detectororelectrostaticgate

1st Electrostatic Mirror 2nd Electrostatic Mirror

Individual electrodesPulsedentry electrode

Pulsedexit electrode

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1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3

g-Sem-SeAsg-Gem-GeGag-Znm-Zn

What you could do with mass resolving power of 400,000:• resolve all isobars• resolve isomers M/DM < 200,000 (470 kev @ A=100)

SeAs

Ge Ga

Zn

A=77

Se.161

Zn.772

Ge.160

T – T0 [microseconds]

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Strawman layout of ORISS at UNISOR

RF-cooler and buncher

RB Ion Source

UNISOR mass separator“pre-separator”

ORISSBeta and

Gamma rayDetectors

Beam diagnostics,electrostaticdecelerator

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Applications of ORISS

Decay spectroscopy with pure sources for p-rich and n-rich

Decay spectroscopy of isomers with sufficient excitation

Survey searches for isomers

Modular Total Absorption Spectrometer - GT strength functions

Future: masses/mass differences

Future: RIB injector

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Physics…

Regions around 100Sn, 132S, 78NiRegions around

100Sn132Sn78Ni

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Physics application: Decay Heat and spectroscopy for advanced nuclear fuel cycle

Many critical measurements can be performed at UNISOR with ORISSAll critical measurements can be performed at UNISOR with ORISS and He-Jet ion source

Elements available with He-Jet ion source