Coupling ORRUBA and GRETINACoupling ORRUBA and GRETINA

Steven D. Pain

Oak Ridge National Laboratory• ORRUBA

• Coupling with GS

• Coupling with GRETINA

• Instrumentation

GRETINA Workshop, ANL, February 2013

Coupling ORRUBA and GRETINACoupling ORRUBA and GRETINA

Steven D. Pain

Oak Ridge National Laboratory

GRETINA Workshop, ANL, February 2013

• ORRUBA

• Coupling with GS

• Coupling with GRETINA

• Instrumentation

Oak Ridge Rutgers University Barrel ArrayOak Ridge Rutgers University Barrel Array

• Barrel array of ion-implanted silicon strip detectors

• Custom resistive design used to achieve good position resolution (~1mm) without requiring 1000s of electronics channels

• 2 rings – < 90°: 12 telescopes (1000m R + 65m NR)

– > 90°: 12 detectors (500m R)

• ORRUBA gives ~80% coverage over = 45° → 135°

• 288 electronics channels

ORRUBA Detector DesignORRUBA Detector DesignE

nerg

y Lo

ss (

MeV

)

1.0

2.0

3.0

4.0

5.0

0.05.0 15.010.0

Residual Energy (MeV)

p

d

GODDESSGODDESS

Gammasphere ORRUBA: Dual Detectors for Experimental Structure Studies

GODDESSGODDESS

New end-cap detectors under design

1 deg (polar) resolution over most angles

15 to 165 degree coverage (>75%)

Polar angle coverage

GODDESS Channel CountGODDESS Channel Count

Total preamplifers = 720 ch (complete coverage requires 616 ch)

One ring 1-layer

(132 ch)

One ring telescopes

(220 ch)

Endcap 1 layer

(128 ch)Endcap 3-stack

(136 - 384 ch)

Backward hemisphere = 260 ch Forward hemisphere = 356 - 604 ch

GRETINA performance for light-ion transfer reactionsGRETINA performance for light-ion transfer reactions

Recoil direction

Recoil energy (target thickness)

Recoil energy (reaction)

Intrinsic resolution of Ge detector

Measured angle of gamma ray

138Xe(d,p) 138Xe(d,t)

~0.5 deg (0.05 deg) ~ 1 deg (~0.1 deg)

~3% ~3%

0.01% 0.01%

2 keV 2 keV

2 deg 2 deg

Gammasphere ~13 keV GRETINA ~3 keV

ORRUBA + GRETINA Physical CouplingORRUBA + GRETINA Physical Coupling

Fits inside standard (DGS) GRETINA chamber

Marginally tighter squeeze inside GS

Room to bring out electronics?

ORRUBA + GRETINA Physical CouplingORRUBA + GRETINA Physical Coupling

InstrumentationInstrumentation

FMA Focal Plane DSSD electronics

320 channels

ORNL electronics

~300 channels

Backward hemisphere = 260 ch

Forward hemisphere = 356 - 604 ch

Complete coverage = 616 ch and up

Conventional instrumentation

FMA Focal Plane DSSD electronics 320 digitizers

+ GRETINA aux channels?

+ DGS?

Digital instrumentation

> 5 feet• Pre-amplifiers mounted on top of “chimney”

• Required some 6 feet of signal cable before any amplification

• Ineffective shielding between feed-through and preamplifiers

• Led to resolution degradation over usual performance (~ 30% effect)

November 2011 – ANL testsNovember 2011 – ANL tests

November 2011 – ANL testsNovember 2011 – ANL tests

Signals run the length of the FMA (2 x 25 ft cables)

Instrumented with RAL shaping amplifiers, and CAMAC ADCs of Darek Sewerniak

Digital

Analog

Data also taken with Darek’s GRETINA digitizers (14 bit, 100 MHz)228Th source for calibration of the ORRUBA detectors, and 249Cf was used to perform an - coincidence measurement

Instrumenting Resistive StripsInstrumenting Resistive Strips

0.5s 1.0s 1.5s

Energy and position filters?

• ORRUBA fits within GRETINA chamber

• Coupling with Gammasphere underway – Hardware built– New end-cap detectors

• Most of GODDESS setup could be equally used with GRETINA– In standalone mode, or if there was sufficient distance to the FMA quad– Radial alternatives possible (would require more hardware fabrication, and

longer un-amplified signal cables)

• Combination of ORRUBA and GRETINA could give excellent (few keV) energy resolution

• Both conventional ADC or digitized readout of ORRUBA are options– Sufficient conventional channels exist– Performance benefits to using digitizers

SummarySummary

AcknowledgementsAcknowledgements

Callum Shand keeping out of the Texas heat Steven Hardy – proud of

his detector mounts

Andrew Ratkiewicz – not entirely convinced by the dinosaurs at the creation museum

Thanks also to the UTK machine shop, Darek Sewerniak, Mike Carpenter, Shaofei Zhu and Kim Lister….

Postdoc

MPhys student

Instrumenting Resistive StripsInstrumenting Resistive Strips

BA

A = Shaping time too short

B = Shaping time better matched

Position Position

Ene

rgy

Instrumenting Resistive StripsInstrumenting Resistive Strips

0.5s 1.0s 1.5s

Energy and position filters?