Rare decays with OTPC

Marek Pfützner

University of Warsaw

2p emission from 48Ni

10 atoms, T1/2 = 2 ms

HIE-ISOLDE Physics Coordination Group, September 3, 2012

Probing the halo of 6He

100%

6He has a very weak decay branch to + d

d

2034 keVdQ 610db

The spectrum of + d

R. Raabe et al., Phys. Rev. C80 (2009) 054307

Raabe

Anthony

Tursunov

Due to -background, it was not possible to

determine the spectrum below ECM 400 keV!

OTPC detection scheme

TriggerRecording

system

d

charge amplification zone GEM foils

e

E

ionizationelectrons

light

HV electrodes

gas at atmospheric pressure

incoming bunch of 6He ions

gating electrode

CCD PMT

REX

IS505, August 2012

IS505, August 2012

6He ions

beta decaysduring 650 ms after implantation

On-line images

ddecay event

PMT

PMT

ddecay event

A different case – 8He

S. Mianowski et al., Acta Phys, Pol. B41 (2010) 449

Decay of 14Be

H. Jeppsen et al. Nucl. Phys A709 (2002) 119

Beta delayed d, , t possible. Only 4 tritons seen.

OTPC @ HIE-Isolde

Possible future application

probing the halo structure by -delayed particle decays in 8He, 11Li, 14Be

● Energy sufficient for implantation of any ion

● Small energy straggling, efficient implantation in a thin gas volume

● Bunching makes search for rare particle channels easier

Advantages of HIE-Isolde

O

● OTPC records tracks of charged particles in 3D

● Ideal instrument for very rare decay modes

● Needs 1 m2 od space (plus a rack od electronics nearby)

● Simple and independent acquisition system (but large data volume)

The detector