DESPEC

A Algora

IFIC (Valencia)

for the Ge array working group

DESPEC (DEcay SPECtroscopy)DESPEC (DEcay SPECtroscopy)Spokesperson: Dr. Berta Rubio

Goal: study of the radioactive beams coming from the SFRS. Tasks: stop the beams, implantation and study

Collaboration: ≥36 Institutes

Basic Instrumentation:

Ge ball (Cube in reality), TAS

Implantation detectors (DSSD detectors)

Neutron detectors

Detector array for measurements of fast timing

Setup to measure electromagnetic moments

Conceptual design

Basic Basic experimentsexperiments

RequirementsRequirements

Beta decay experiments in the classical sense

(trigger can be provided by the signals left by the betas in the implantation detector)

High gamma efficiency, High gamma efficiency, background reduction , background reduction , good E resolutiongood E resolution, and , and position resolutionposition resolution

(tracking can be used to (tracking can be used to improve the peak to total improve the peak to total ratio, and probably to ratio, and probably to reduce background)reduce background)

Isomer decay experiments

Imaging techniques can Imaging techniques can be used to track the be used to track the position of the decay and position of the decay and reduce backgroundreduce background

DESPECDESPEC

Possible Ge arraysPossible Ge arrays

DetectorsDetectors 2424

No. of planars No. of planars (stack)(stack)

33

No. de strips No. de strips (planar)(planar)

8 x 88 x 8

No. of electronic No. of electronic channelschannels

11521152

Detectors 6 ó 8

Preamps per detector

52 (48 +4)

Number of channels

312 (416)

8x24 cm2

Planar ArrayPlanar Array

Composite detectors: Ge planar Composite detectors: Ge planar detectors of 72x72x22 mm3, active detectors of 72x72x22 mm3, active volume of 68x68x22 mm3. Guard ring volume of 68x68x22 mm3. Guard ring of 2 mm thickness. Al capsule of 1.5 of 2 mm thickness. Al capsule of 1.5 mm thickness. Al-Ge, and Ge-Ge mm thickness. Al-Ge, and Ge-Ge distance 3mm. distance 3mm.

Geant4 simulations have been Geant4 simulations have been performed (0.1 mm cuts and low energy performed (0.1 mm cuts and low energy physics for the different setups)physics for the different setups)

Modified Tigress ArrayModified Tigress Array(backup solution) clover (backup solution) clover

4x60x90 seg 484x60x90 seg 48Size of the individual crystals:

• Diameter 60 mm before shaping

• Length of the crystal 90 mm

Additional details:

• Longitudinal segmentation x4

• Transversal segmentation x3 (25,25,40)

• Separation of less than 7 mm from the exterior surface of the Al cap

• Separation between the crystals less than 0.7 mm

Synergies with the Synergies with the Network:Network:

research and research and developmentdevelopment• Collaboration with AGATA (we are already in Collaboration with AGATA (we are already in

contact with the Padova group) for the use contact with the Padova group) for the use and development of codes to apply tracking and development of codes to apply tracking techniques for the DESPEC arraytechniques for the DESPEC array

• Pulse shape analysis (fundamental for our Pulse shape analysis (fundamental for our working group, collaboration is needed)working group, collaboration is needed)

• Development of detectors (planar prototype, Development of detectors (planar prototype, TAS)TAS)

• Applications of Monte Carlo techniques (we Applications of Monte Carlo techniques (we can train people in this field)can train people in this field)

• Application of imaging techniquesApplication of imaging techniques

Efficiency assumingEfficiency assumingfull tracking!!full tracking!!

EE(MeV)(MeV)

EffEff(peak)(peak)

P/TP/T EffEff(tot)(tot)

0.100.10 47.647.6 91.291.2 53.753.7

0.250.25 38.738.7 67.567.5 57.457.4

0.500.50 27.227.2 49.749.7 55.655.6

1.001.00 19.019.0 38.038.0 50.350.3

2.002.00 12.712.7 28.928.9 44.544.5

5.005.00 6.56.5 16.616.6 39.639.6

10.010.000

3.43.4 8.78.7 39.739.7

EE(MeV)(MeV)

EffEff(peak)(peak)

P/TP/T EffEff(tot)(tot)

0.100.10 36.436.4 78.578.5 46.346.3

0.250.25 30.730.7 66.566.5 46.246.2

0.500.50 23.523.5 53.953.9 43.643.6

1.001.00 18.018.0 44.244.2 40.740.7

2.002.00 12.912.9 35.335.3 36.636.6

5.005.00 7.17.1 21.721.7 32.832.8

10.0010.00 4.04.0 14.014.0 28.728.7

Planar setup Clover setup (6 clovers)

A Monte Carlo code has been also developed to evaluate the tracking efficiency of the different Ge arrays

(collaboration with the AGATA group of Padova)

A.Algora et al GSI annual report 2006