Anger Camera for neutrons
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Anger Camera for neutrons. F. A. F. Fraga, L. M. S. Margato ,S. T. G. Fetal, M. M. F. R. Fraga, A. Morozov, L. Pereira, R. Ferreira Marques, P. Mendes, J. P. Rodrigues LIP Coimbra, Universidade de Coimbra. FP6 NMI3 JRA2 RII3-CT-2003-505925 ended 2008.

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Anger Camera for neutrons

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Anger camera for neutrons

Anger Camera for neutrons

F. A. F. Fraga, L. M. S. Margato ,S. T. G. Fetal, M. M. F. R. Fraga, A. Morozov, L. Pereira, R. Ferreira Marques, P. Mendes, J. P. Rodrigues

LIP Coimbra, Universidade de Coimbra


Anger camera for neutrons

FP6 NMI3 JRA2 RII3-CT-2003-505925 ended 2008

  • MILAND – development of thermal neutron detectors

  • Would increase knowledge about neutron detectors, but should have a deliverable

  • working detector prototype with a firm and clear specification

  • 32 x 32 cm2 detector

  • 1 mm resolution (FWHM) res/length = 3x10-4

  • 1 MHz global count rate

  • 100 kHz / mm2 local (peak) count rate

  • Gamma background rejection 10-8

  • 50% efficient at 1.8Å

  • parallax free

  • Cost is critical

  • Partners and Observers

  • P1 CCLRC N. Rhodes (UK) T3, T6, T7

  • P2 GKSS R. Kampmann (Germany) T1, T4, T5, T6, T7

  • P3 BNC L. Rosta (Hungary) T1, T5, T6, T7

  • P4 ILL B. Guerard (France) T1, T2, T3, T4, T5, T6, T7 coordinator

  • P5 LLB C. Fermon (France) T2, T4, T6, T7

  • P6 FRM-II K. Zeitelhack (Germany) T1, T2, T4, T6, T7

  • P7 LIP F. Fraga (Portugal) T2, T3, T6, T7ObserversEFO1 BNL G. Smith (USA)

  • EFO2 SNSR. Cooper (USA)

  • EFO3 TU H. Takahashi (Japan)

  • EFO4 RAL J. Mir (UK)

  • EFO5 BNL R. Krueger TU Delft (NL)

Integrated Infrastructure Initiative for Neutron Scattering and Muon Spectroscopy


Anger camera for neutrons

Neutron Detectors

nuclear reactions to convert neutrons

  • n + 3He  3H + 1H + 0.764 MeVGaseous detectors (CF4, prop.)

  • n + 6Li  4He + 3H + 4.79 MeVScintillators

  • n + 10B  7Li* + 4He7Li + 4He + 0.48 MeV +2.3 MeV(93%) 7Li + 4He +2.8 MeV( 7%)

  • n + 155Gd Gd* -ray spectrum  conversion electron spectrum

  • n + 157Gd Gd* -ray spectrum  conversion electron spectrum

  • n + 235U  fission fragments + ~160 MeV

  • n + 239Pu  fission fragments + ~160 MeV


Scintillators for neutron detectors

Scintillators for Neutron Detectors

CWE van Eijk, NIM A529(2004)260-267


Gaseous detectors n 3he 3h 1h 0 764 mev cf4 should be added to control the range 3 bar for 1mm fwhm

CF4+*, CF3+*

CF3*

Gaseous detectorsn + 3He  3H + 1H + 0.764 MeVCF4 should be added to control the range -3 bar for 1mm FWHM

  • CF4 is a good scintillator, but only a few primary photons

  • Secondary scintillation ~.3 photon per secondary electron


Anger camera for neutrons

Scintillation Anger camera

PMT base

PMT base

PMT

PMT

Transparent window

gas

MSGC

Neutron window


Anger camera for neutrons

New MSGC Batch

  • Remarks

  • Cathodes width of the new set of microstrips is more or less half of the older ones (181 mm vs.398mm) and the anodes seems to be larger.

  • To achieve the same charge gain the new microstrip needed a higher anode voltage than the older one.

  • For instance, at 1 bar of CF4, to reach a gain of G ~103 we should apply a voltage of Va~1900V, something like 840V more than in the older microstrip (Va=1060V).

  • Taking off the drawbacks linked to a higher voltage, the light yield obtained with the new microstrip (for G ~103 ) is ~ 0.263 ph/sec-e, about 4.5 times higher than the light yield in the older one (~0.045 ph/sec-e).

  • This MSGCs batch are unable to operate above 1 bar CF4 (discharges).

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

Charge gain and light/charge versus anode voltage 15, 20 and 30µm anodes CF4 (1bar)


Anger camera for neutrons

New MSGC Batch

  • Charge and light measurements

Number of emitted photons per secondary electron

Charge gain versus anode voltage

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

MSGC ILL6C at High pressure

  • Measurements at 3 bar CF4

Number of emitted photons per secondary electron

Charge gain versus anode voltage

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

Simulations F.Fraga, Hamburg meeting


Gspc details

GSPC details


Anger camera for neutrons

Aquisition system by Acquiris and E. Shooneveld

GSPC in position at the ILL beam


Anger camera for neutrons

2D position images Vanode = 1360, 1550 1650 and 1850V


Mask 1650 3 eve va 1650 v vpmt 800 v

Mask_1650_3.eve: Va=1650 V; VPMT= 800 V.


Mask 1650 3 eve va 1650 v vpmt 800 v1

Mask_1650_3.eve: Va=1650 V; VPMT= 800 V

FHWM center peak 1.63 mm

FHWM center peak 1.68 mm


Fwhm resolution versus v anode

FWHM resolution versus Vanode

  • For the best safe conditions (Vanode =1850 V; VPMT= 800 V) the intrinsic resolution is 1.1mm after we deconvolute the beam width


Detector uniformity 1850v

Detector uniformity (1850V)


Typical pmt signals

Typical PMT signals

High amplitude – good discrimination

Very fast signals – risetime ~20ns


Anger camera for neutrons

Transparent electrode MSGC

  • Manufactured at the Tokyo University and supplied by Hiroyuki Takahashi

  • 90% ITO electrode transparency

  • The transparent window can be the active element

  • Multigrid approach proposed –it has the advantage of a very high local count rate.


Anger camera for neutrons

ITO M - MSGC

  • Photographs

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

ITO M - MSGC

  • Experimental Setup

  • Driftlength = 10 mm

  • Distance between microstrip and PMT = 34.8mm

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

ITO M - MSGC

  • Ar+5%CF4 (1atm, 100cc/min.) and CF4 (1atm, 100cc/min.)

Number of emitted photons per secondary electron

Charge gain versus anode voltage

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

ITO M - MSGC

  • Effect of GRID potential (Vg) on Gain and light yield

Charge gain versus anode voltage for several GRID voltages

Number of emitted photons per secondary electron

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

60ns

100 mV

ITO M - MSGC

  • Example of typical signal taken directly from the PMT Hamamatsu R1387 (RL=50 W): 55Fe (5.9keV) X-ray source

  • 100%CF4 (1atm)

  • Vdrift= -500V, Vcathode=0

  • Vanode=990V Vg1= 600V

  • VPMT=-1000V

NMI3 Meeting, CORSICA, 25-28th June 2008


Anger camera for neutrons

MSGC ILL6C at High pressure

  • Measurements at 3, 4 and 5 bar CF4

Number of emitted photons per secondary electron

Charge gain versus anode voltage

NMI3 Meeting, CORSICA, 25-28th June 2008


2009 2011 fp7 wp22 cp csa infra 2008 1 1 1 number 226507 nmi3

2009-2011 FP7 WP22CP-CSA_INFRA-2008-1.1.1 Number 226507-NMI3

Development of new thermal neutron detector technologies based on Gaseous Scintillation Proportional Counters (GSPC) • Explore their potential to overcome the limitations in light output and rate capability of existing scintillation detectors • Investigate their potential as high resolution detectors for Reflectometry or time resolved SANS. • Built and study small scalable prototypes

http://detectors.neutron-eu.net/Detectors


Anger camera for neutrons

The new family members, born in Munich two months ago!

We will go on studying the scintillation and the PMT readout


The good not so good new

The good not so good new

  • European Spallation Source (ESS) went to Lund in Sweden

    The bad new

  • 3He crisis


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