Gopal Mukherjee

Variable Energy Cyclotron Centre

1/AF Bidhan Nagar

Kolkata, INDIA

On behalf of MONSTER Collaboration

Development of neutron detectors for

MONSTER collaboration

NUSTAR Annual Meeting 26/02 – 02/03, 2018 GSI, Germany

MONSTER � MOdular Neutron SpectromeTER array

� is being developed for DESPEC (DEcay

SPECtroscopy) experiments

� Will consists of 100 liquid scintillator based

fast neutron detectors

� Will be useful for the investigation of β-decay

properties of neutron rich nuclei

� As a part of the collaboration 42 detectors

will be developed by Indian collaborators

General view for the 35 detectors of

MONSTER demonstrator

Exploded drawing

view of the

detector full

assembly

β-delayed neutron emission

� Practical application in reactor control

� Importance in basic nuclear structure physics

� Important measured quantities are:

• delayed neutron emission probability, Pn

• Neutron energy spectra

Fission

Liquid cell

Light guide

PM tube

Optical fiber connector for gain matching

The design of the MONSTER detector has been finalized after detailed technical simulation

Cell Size: 200 mm dia, 50 mm length

Material: Aluminium alloy (6061T6)

Scintillator: BC501A or equivalent

PMT: 127 cm HAMAMATSU R4144

MONSTER: a TOF Spectrometer for β-delayed

Neutron Spectroscopy

T. Martinez et. al, Nuclear Data Sheets 120 (2014) 78

MONSTER Detector

Development of the proto-type detector at VECC: Different steps

1

2

3

4

5

6

7

1. Cleaning (removal of any suspended particles)

2. de-oxygenation

3. Liquid filling (vacuum suction technique)

4. Different components

5. Coupling of light guide

6. Sealing of liquid scintillator cell

7. Proto-type detector

Detector Characterization

PH response

� The pulse height response of the

detector has been studied using a137Cs γ-ray source.

� The response has also been

estimated using Monte Carlo

simulation.

The pulse height resolution at the

Compton edge (471 keV), was found to be

around 10% in the present case

Pulse Shape Discrimination

The pulse shape discrimination

were studied through the zero-

crossover technique using the

Mesytec-MPD4 module

n

γ

Source: 241Am-9Be

ZC

T

PH

Threshold (keVee)

0 500 1000 1500 2000 2500

FO

M

0.4

0.8

1.2

1.6

2.0

Figure of MeritTOF (Channel No.)

ZC

O (

Ch

an

nel

No.)

γ

n

60Co

Time resolution

BaF2MONSTER Detector

� The time resolution has been

determined with reference to a fast BaF2

detector (1 inch), having time resolution

≈400 ps (determined separately)

(∆t)mon ≈ 0.90 ± 0.07 ns

Time (ns)

-5 -4 -3 -2 -1 0 1 2 3 4 5

Co

unts

1000

2000

3000

4000Data

Gauusian fit

En (MeV)

0 2 4 6 8 10 12

Eff

icie

ncy

0.0

0.4

0.8

1.2

Experimental

NEFF

Energy dependent efficiency

� The detector efficiency was measured using 252Cf source with fission trigger taken

by direct fission fragment detection by small ionization chamber with the 252Cf source

mounted on one of the electrodes.

Fission ionization chamber

3/2(T)π

E/T)exp(E2N(E)

−=

252Cf reference spectra

1.5 m

� Measured efficiency is in good

agreement with the Monte Carlo

simulation (NEFF).

� Based on the proto-type

development 10 detector modules

for the MONSTER have already been

fabricated and tested at Kolkata.

The MONSTER modules are being

successfully used for neutron

spectroscopic measurements at VECC

K. Banerjee et al, Phys. Lett. B 772 (2017) 105

Pratap Roy et al, Phys. Rev. C 94, 064607 (2016)

Proposed digital DAQ for MONSTER

� The detector pulses will be digitized using four channel, 14 bit, 1 GSPS digital ADC

cards (ADQ-14 by SP Devices or equivalent)

� Total data acquisition system can be divided into four streams having 7/8 digitizer

boards placed inside a PCIe expansion box connected with a high end PC having Xeon

Phi processor.

� A MONSTER Master Controller (MONSTER MC) is to be designed as the master

application to control, monitor and data logging for all the MONSTER DAQ Stations.

MONSTER MC

Client Station

(Stream) 1

Client Station

(Stream) 2

Client Station

(Stream) 3

Client Station

(Stream) 4

7/8 digitizer board 7/8 digitizer board 7/8 digitizer board 7/8 digitizer board

Control and synchronization:

White Rabit board

Total system

consists of 4

units total 128

channels. Each

unit can work

independently

XEON PHI PROCESSOR

P

C

I

e

e

x

p

a

n

s

i

o

n

b

o

xADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ST

ER

AM

1

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

XEON PHI PROCESSOR

XEON PHI PROCESSOR

XEON PHI PROCESSOR

Master PC

Network

WR Slave

WR Slave

WR Slave

WR Slave

ST

ER

AM

2S

TE

RA

M 3

ST

ER

AM

4

Single Unit

Data acquisition scheme

STERAM 1

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

ADQ 14 BOARD

PCIe

expansi

on box

DETECTOR

DETECTORXEON PHI PROCESSOR

Each unit (stream) consists of

• 8 digitizer boards

• each having 4 channels.

WR Slave

Configuration of a single unit

Server Specification

• 2 × 12 core Xeon Processor

• 2 × Intel Xeon Phi processor

• 128 GB RAM

• HDD 6 × 4 TB

• 2 × 24 inch LCD Display

• High end graphics card

• 4 PCIe slot

PCIe expansion box

18 slots

Digitizer board ADQ14

14 bit, quad channel

1 Gsamples/sec

PCIe interface

Xilinx Kintex 7 FPGA (user prog)

White Rabit System

White Rabit Master module

White Rabit slave module

DAQ system specification

Stand alone setup for 32 channels planned to be developed

by Indian collaboration

• Digitizer board ADQ14 and firmware

• PCIe bus expansión box

• High end PC

• White Rabit Board for Synchronisation

Software and Control Program

• Development of online monitoring software for the DAQ on a

ROOT platform

• Control program for the Master PC for the synchronisation of

streams, sharing of the configuration file etc

• Analysis program

Indian Contribution on DAQ

� The digital DAQ is being developed in close collaboration with CIEMAT,

Madrid.

� Preliminary acquisition and analysis software (DAISY) for data taking

using one ADC card has been developed by the CIEMAT group.

� Program for the Master controller and online visualization is being

developed by VECC.

Present status of the digital DAQ

� The online DAQ is being developed completely using ROOT classes.

� The control software part is being developed using QT 5.8. So far the

network interface part is being developed. The performance of queues for

concurrent data handling at high rate is being tested.

Overall status

� Ten detector modules have been fabricated and tested in

Kolkata. A few other detectors are also ready at CIEMAT.

� The digital DAQ is ready for stand alone use. Another DAQ

is being developed in Kolkata in collaboration with CIEMAT.

� The Indian part of the in-kind contract with FAIR for

MONSTER has been finalized and ready for signatures.

� Draft MOU between VECC and Bose institute has been

prepared and send for DAE approval.

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