ROGER CABALLERO-FOLCH Universitat Politècnica de Catalunya 26 de febrer de 2013 NUSTAR ANNUAL MEETING - 2013 GSI Darmstadt, Germany Beta dELayEd Neutron

ROGER CABALLERO-FOLCHUniversitat Politècnica de Catalunya

26 de febrer de 2013

NUSTAR ANNUAL MEETING - 2013

GSI Darmstadt, Germany

Beta dELayEd Neutron (BELEN) detector status

Detection system

Previous versions used at JYFL and GSI – Design and analysis/results status

Contents

Previous versions New designsDetection system

New designs and conclusions

1

Detection system


Contents

Previous versions New designsDetection System


2

Detection system

β delayed neutron emission

3

Previous versions New designsDetection SystemDetection system

3He counters as detector

The detection of the neutron is based on an indirect method: the detection of

the products of the reaction of the neutron with 3He counters:

3He + n 3H + 1H + 765 keVOther reactions:

10B + n → 7Li* + 4He + 2310 keV

7Li* → 7Li + 480 keV

Ion beam

n

n

n

Polyethylenemoderator

Proportional 3He counter

Silicon

β decay detector

Counter Gas Maximum length (mm)

Effective length (mm)

Maximum diameter

(mm)

Effective diameter

(mm)

Gas pressure

(atm)

Cathode material

2527 LND inc

3He 686.84 604.8 25.4 24.38 20 / 10 / 8

Stainless Steel

4


Noise

Neutron signal

5

Electronic chain for data acquisition and signal processing

Analog system: Trigger

Digital system: Triggerless

Digital Data Acquisition System (DDAS)

J. Agramunt & IFIC team

The electronic chain of the

acquisition system

operates independently

of the other systems of the

experiment and detectors

along the beamline. It only

needs to synchronize the

timestamp.


Detection system


Contents



6

Previous versions

7

Tests and experiments with BELEN detector

Neutron number N

GSI:S410 “Measurement of β-delayed neutrons around the 3rd r-process peak” C. Domingo-Pardo et al.PERFORMED, September 2011

GSI: S323 “Beta-decay of very neutron-rich Rh, Pd, Ag nuclei including the r-process waiting point 128Pd”. F. Montes et al.PERFORMED, September 2011

Z=28, N=50;

JYFL (2009, 2010 & 2013)I162 “Delayed neutron measurements for advanced reactor technologies and astrophysics” JL Taín JYFL. Expected 2013B.Gomez-Hornillos et al. NIM in progress (2009 exp)

Z=50, N=82

Previous versions New designsDetection system Previous versions

Background measurements at GSI (2010) and LSC Canfranc (2011) D.Jordan et al. Astr.Phys Vol.42, Feb 2013, p.1–6

Support structure requirements:

Hold and transport 650 Kg

Allow access to the beam hole

Movable in Z for fine placement

Table + tray movable on “z” on rails

Polyethylene matrix hold together and

can be lifted as a single unit.

Polyethylene: 10 cm thick vertical

slices assembled => 90 x 90 x 80

cm3 ~650 Kg detector

Fixed support

Moving tray

BELEN design for JYFL experiments

8


JYFL experiment 2009 & 2010 - BELEN-20

20 3He counters at 20 atm

1ST ring: 8 counters at 11 & 9.5 cm

2nd ring: 12 counters at 20 & 14.5 cm

Average efficiency: 27% & 35% (5MeV)

Dimensions: 50x50x80 cm3 + shielding (90x90x80 cm3)

Diameter holes: 2.75 cm

Central hole radius: 5.5 cm

9


S410/S323 experiments at GSI (2011). Design & efficiency.

BELEN-30: 20 3He (20 atm) & 10 3He (10 atm)

Inner ring (10 counters): 29 cm

Outer ring (20 counters): 37 cm

Efficiency (1keV-1MeV) ~40%

Average up to 5MeV ~ 35%

Central hole radius: 11.5 cm (SIMBA)


252Cf neutron source detection efficiency (M.Marta):

MCNPX simulation: (34.5±0.2)%

Triggerless DACQ (IFIC) in MBS : (35.4±0.8)%

Analog branch: (25.5±0.9)% (electronics)

Silicon Implantation Beta Absorber (SIMBA)

10

Results and ongoing analysis S410 experiment


11R.Caballero-Folch, C.Domingo-Pardo et al.

Hg

Au

Pt

Tl

Pb

Bi

Po

At

Rn

211Hg

215Tl

Results and ongoing analysis S410 experiment


12R.Caballero-Folch, C.Domingo-Pardo et al.

Results and ongoing analysis:


Counts

Count

s

Time β-neutron (ms)

Time β-neutron (ms)

N

NP n

nn

1

13

Performance test time correlation between neutron and β-decay for 213Tl

R.Caballero-Folch, C.Domingo-Pardo et al.

Detection system


Contents



14

New designs

Recent improvements for BELEN design

The number of 3He counters has been duplicated and their pressure changed

from 20 atm to 8 atm. The cost of this improvement is around 150.000€.

New MC simulations for future BELEN versions to perform more experiments at

JYFL (IGISOL trap) and the design with AIDA (changes on central hole radius).

Planarity (flat efficiency) optimization to different energy ranges up to 2MeV or

5MeV.

GEANT4 simulations are being done to compare MC simulations and the

correlation has been checked.

15

Previous versions New designsDetection system New designs

BELEN versions designed

Name3He

countersPressure

(atm)Experimen

t

Ratio@

2 MeV

Ratio @

5 MeV

Average efficienc

y

Central hole radius

(cm)

BELEN-20 20 20 JYFL-2009 1.17 [1.60] 27% 5.5

BELEN-20 20 20 JYFL-2010 1.17 [1.60] 35% 5.5

BELEN-30 20+10 20 & 10 GSI-2011 1.17 [1.70] 35 % 11.5 (SIMBA)

BELEN-48 40+8 8 & 10 JYFL-2013 1.02 1.16 54%-39% 5.5

BELEN-48 40+8 8 & 10 DESPEC 1.04 1.15 45%-34% 8 (AIDA)

Observe: Central hole, num. counters & planarity

16

)efficiencyn min(neutro

)efficiencyn max(neutroRatio

max(neutron efficiency)

min(neutron efficiency)

To define the efficiency flatness for a range of neutron energies


5MeV2-5MeV

BELEN design for JYFL 2013

17

Radius of central hole: 5.5cm.

Neutron energy range 100 keV – 5 MeV

Planarity optimization

Name 3He counters Pressure (atm) Ratio 2MeV Ratio 5MeVAverage

EfficiencyCentral hole radius (cm)

BELEN-48 40+8 8 & 10 1.02 1.16 39% 5.5

12

3

2

1

3

total



18

Name 3He counters Pressure (atm) Ratio 2MeVAverage


BELEN-48 40+8 8 & 10 1.10 54% 5.5

3

21

1

2

3

total


Neutron energy range 100 keV – 2 MeV

Efficiency optimization



19



Efficiency Vs planarity optimization

1MeV

1MeV

5MeV

New BELEN design in progress for AIDA

20

Name 3He counters Pressure (atm) Ratio 2MeV Ratio 5MeVAverage


BELEN-48 40+8 8 & 10 104 115 34% 8 (AIDA)

1

3

2

3

2

1

total

Optimized for neutron energy range 100 keV – 5 MeV

Radius of central hole: 8 cm

Planarity optimization


21

New BELEN design in progress for AIDA

Name 3He counters Pressure (atm) Ratio 2MeVAverage


BELEN-48 40+8 8 & 10 106 45% 8 (AIDA)

Optimized for neutron energy range: 100 keV – 2 MeV

Radius of central hole: 8 cm

total

1

2

3

1 2

3

Efficiency optimization


Summary of design parameters

Define the energy range of the neutrons to optimize the desired flat

efficiency

Number of counters available Polyethylene matrix

Radius of central hole Implantation detector and beamsize

Knowledge of the estimation neutron background to decide the shielding

Support structure.

22


BRIKEN (BELEN @ RIKEN) meeting

23


IFIC – UPC – CIEMAT – MSU – Edinburgh – GSI – RIKEN – Tennessee

Analysis of the facility to perform experiments with BELEN + AIDA at RIKEN

Discussion of what kind of experiments can be done and regions to explore.

Possibility of a campaign of measurements in the near future

Conclusions:

Interest of all parts involved

Possibility to increase BELEN efficiency with RIKEN 3He counters

Conclusions (I)

MC simulations indicates that the overall neutron detection efficiency

depends on the 3He pressure and the number of counters (among other

variables).

The number of counters is more significant than gas pressure.

(Reason of change of the 21 counters at 20atm to 42 at 8atm)

The inner ring gives the maximum efficiency but for lower energies.

The position of the outer ring is determinant to evaluate:

A) the efficiency of the higher energy to optimize

B) the neutron background and the shielding design due to the

thickness of the polyethylene around the crown.

New experiments will be done with 42 counters at 8 atm (UPC) + 10

counters at 10 atm available (GSI). 24


Conclusions (II)

BELEN is a 4π neutron detector designed to study β delayed neutron emission

Laboratory tests and several successful experiments performed (Barcelona, JYFL,

LSC - Canfranc and GSI).

The efficiency of the previous configurations has been validated experimentally

with 252Cf sources and some reference isotopes.

Flat efficiency is obtained up to neutron energies of 5 MeV

Average efficiency of 34% for 8 cm central hole (AIDA) for neutron up to 5 MeV

Average efficiency of 45% for 8 cm central hole (AIDA) for neutron up to 2 MeV

Neutron efficiency calibration at PTB next June 2013

Proposal approved at JYFL for this year.

TDR: Ongoing, expected to include calibrations at PTB improvements presented

25


BELEN detector team

Work supported by the Spanish Ministry of

Economy and Competitivity under contract

FPA 2011-28770-C03-03

UPC (Barcelona) R.Caballero-Folch, F.Calviño, G.Cortès, A.Poch, C.Pretel, A.Riego, A.TornerOld members: M.B.Gómez-Hornillos, V.Gorlychev

IFIC (València)J.Agramunt, A.Algora, C.Domingo-Pardo, D.Jordan, J.L.Taín

GSI (Darmstadt – Germany)I.Dillmann, A.Evdokimov, M.Marta

CIEMAT (Madrid)D.Cano-Ott, T.Martínez, E.Mendoza, A.García-Ríos

Host Lab requirements for BELEN. Details in documentation.

2013/14: Set-up at S4 in combination with AIDA (Optimization tests )

Beam 238U primary beam at 900MeV/u 2x109 intensity (10 shifts)

Space 25 m2 , background, readout -and acquisition systems, time,

correlations ,(10 days each year)

10 visitors for preparation of tests, online analysis, etc.

2017: Final set-up at S4 with AIDA

Beam 238U primary beam at 900MeV/u 2x109 & 2x1010 intensity

Space 25 m2, installation and final test prior to commissioning (14 days)

10 visitors for commissioning preparation, online analysis, etc.

2018: COMMISSIONING (20 visitors expected)

General: , DACQ & MBS system experts, Internet connections and offices for

visitors, Mass storage.27


+1

Triggerless digital data acquisition system:

Struck digitizer modules (SIS3302): provide time-stamps very versatile for

time correlations

Negligible dead-time when compared to analog systems

Increase the efficiency.

Flexibility for large time correlation (fundamental to obtain correlations with

all neutron and to change the gates offline)

Allows to correct some experimental effects, e.g.

To reduce neutron background from uncorrelated

neutrons

Being developed at IFIC (València-Spain)

Digital Data Acquisition System (DDAS)


+2

Experimental hall for background measurements at GSI


+3

Experimental hall for background measurements at LSC


D.Jordan et al. Astr.Phys Vol.42, Feb 2013, p.1–6

+4

BELEN design for JYFL experiments (2009 & 2010)

Prototype designed for JYFL 2009 with 20 counters

Penning Trap(High purity Beam)


+5

BELEN design for JYFL experiments (2009 & 2010)


MCNPX simulation efficiency

+6

BELEN design for GSI experiments 2011


MCNPX simulation efficiency

Polyethylene shielding

Rings of 3He proportional countersR1=12.5 cm and 8 counters, R2=18.5 cm and 12 counters.

Polyethylene matrix

Beam hole r=5 cm

Neutron source

Developed by V.Gorlychev and B.Gomez at UPC-

Barcelona

BELEN first designs and geometry

The geometry design is based in two rings. The aim is to have a flat efficiency in the energy range of interest (100 keV – 5 MeV).

+7


Other designs proposed• 3 crowns with 16 counters each at 10 & 8 atm• 3 crowns with 16 counters each at 4 atm• Total 96 counters• Old simulation not optimized

+8


Documents

ROGER CABALLERO-FOLCH Universitat Politècnica de Catalunya 26 de febrer de 2013 NUSTAR ANNUAL MEETING - 2013 GSI Darmstadt, Germany Beta dELayEd Neutron