The 10B-based Jalousie Neutron Detector

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CDT

The 10B-based Jalousie Neutron Detector

DENIM 2015, Budapest, 8.09.2015

Christian J. Schmidt

Our solution for POWTEX (FRM-II) as alternative for

3He-filled PSD counter tubes

CDTCascade Detector Technologies GmbH

Hans-Bunte Str. 8-10

69123 Heidelberg, Germanywww.n-CDT.com

Solid state and quantum chemistry

JCNSZAT, ZEL

VerbundforschungNico Walte

High pressure station SAPHiR

Jens Walter

Christian Randau

Texture analysis

H. Conrad, Th. Brückel, W. Schäfer, J. Voigt, J. Appl. Cryst. 41., 836 (2008).A. Houben, W. Schweika, Th. Brückel, R. Dronskowski, Nucl. Instr. and Meth. A 680, 124 (2012).

CDT GmbH contracted by RWTH Aachen for concept, design and realization at FRM II, cooperation with FZJ/JCNS through JARA

Project leader: Andreas HoubenRWTH-Aachen

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Christian J. Schmidt, CDT GmbH Heidelberg, DENIM 2015

Neutron detection with 10B converters10B + n → 7Li (1.02 MeV) + α (1.78 MeV) ( 6%)

→ 7Li (0.84MeV) + α (1.47 MeV) + γ (0.48 MeV) (94%)3838 b (1.8 A)

� 10B and 10B4C are stable, inert (compared to BF3) and non hygroscopic (as e.g. Li, BF3)

� > 96% enriched 10B available (through large industrial demands for 11B)

� large charge-signal inside detector

� Ranges of α (3.14 µm) and 7Li (1.53 µm) limit single layer detection efficiency to ~ 5% forthermal neutrons at vertical incidence

0 25 50 75 100 125 150 175 200 225 250

2000

4000

6000

8000

10000

Counts

PHA channel number

UCN's

50 nm 10

B

pic

ture

fro

m K

. Z

eitelh

ack, F

RM

2

α7Li

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Jalousie for POWTEX

� Jalousie is a detector solution with inclined, solid 10B or 10B4C converter layers.

� Boron coatings are inclined to the neutron path to

geometrically enhance converter depth,

� while nuclear fragmentation products still enter the gas detector to deposit a large

charge-signal.

� At η = 10° the effective converter depth is 5.75 times higher.

ηd/Sin(η)

d10B layer

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einfallender Neutronenstrahl

beidseitig mit 10-B beschichtete Lamelle

Zähldraht in der Mitte zwischen 2 Lamellen

k = 1

Ausführungstiefe k = 2, Anzahl der potentiell getroffenen Lamellen

k = 3

Potentialdraht zur Feldformung

ηηηη

h

b

Jalousie: Detector Concept – neutrons at scraping incidence

10B-coated lamellae are inclined to the incoming neutron

intensity at an angle of η = 10°

projected depth k = 4 (corresponds to 8 Boron layers)

counting anode wirebetween two lamellae potential wire

lamella coated with 10B4Con both sides

incoming neutronsk = number of traversed lamellae

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Jalousie: Modular and Segmented

� Any neutron will pass 8 layers of Boron (1,1µm) under 10°, overall 46µm of 10B

� In-depth detection as well as resolution to achieve TOF resolution

� Modular detector segments as individually operating proportional gas detectorswith two anode planes each that may be assembled to cover large areas

segment crossection

segment side view

neutrons

From point of view of incoming neutrons: the stack of inclined lamellae looks like a „Jalousie“ or Venetian blind.

neutrons

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Projected Detection Efficiency

Efficiency as function of wavelength, η = 10°, 8 10B4C layers

1,0 1,5 2,0 2,5 3,0 3,5 4,050

55

60

65

70

75

80

1,1 µm 10B4C

D

ete

ction E

ffic

ien

cy [

%]

Neutron Wavelength [Angström]

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1 2 3 4 5 6 750

55

60

65

70

75

80

85

90

1,1 µm 10B4C

0,65 µm 10B4C

D

ete

ction E

ffic

iency [%

]

Neutron Wavelength [Angström]

Efficiency may be optimized for the application

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Jalousie Configuration for the POWTEX cylinder

neutrons

segment crossection

segment side view, 1,6m active length

All-active detector entrance area, no blind areas !

neutrons

240 segments1,14° coverage each segm.cylinder inner radius: 80cm

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POWTEX Instrument, towards 4ππππ-Coverage� Cylinder jacket coverage 274°, 240 segments

� Two end-caps, ϕ-coverage 276° each

� No coverage on bottom � space for instrumentation

� 2 Mio. active Voxels, 60.000 analog ASIC r/o channels

overall blind area < 5,8%

9 sqm detector area

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Neutron Powder Diffractometer POWTEX w

ith

pu

lsed

bea

m, T

oF

~ λλ λλ

calculation thanks to Dr. Werner Schweika, FZJ

forwardendcap

barrel jacket backwardendcap

example: NAC standard

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Realization of POWTEX-Jalousie at FRM II

� Jalousie was elaborated in two prototypingiterations.

� Third iteration: Production pre-series (12 segments).

� Serial Production started,

26/240 segments assembled, ~40% coating done (~280 sqm), all electronics manufacturedassembly capacity: ~3 segments per week

module pair

at FRM II, HEIDI

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Measurements at Triga Reactor Mainz

Beam from collimated slit onto Jalousie segment at 10°(both wire planes shown side by side)

Uncollimated beam profile measured withCASCADE 2D-200

Log-plotLog-plot

1/3

ofcath

ode

str

ips

#1 wire plane #2

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508 510 512 514 516 518 520 522 5240

500

1000

1500

2000

2500

3000

co

unt

rate

[H

z]

θ-position [mm]

152 156 160 164 168 172 176 1800

1000

20003000

4000

5000

60007000

8000

900010000

Cou

nts

z position [mm]

2

Resolution scan across cathode strips

Resolution scan across anode wires

Measurements at Triga Reactor Mainz, Prototype II

employing collimator: beam width 0,5mm in detector

measured resolution: ∆2θ = 0,38° FWHM

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Jalousie Specifications to meet POWTEX Needs

•Very low γγγγ-background: Low-Z converter material 10B, alpha versus e-ionization density

•Long term stability due to continuous purge of cheap counting gas through detector.

Accumulated detection efficiency

� 8 boron layers

� inclined at 10°

> 52% (1.0 Å)

> 65% (1.8 Å)

> 72% (2.5 Å)

spatial resolution (2D) (at ambient counting gas pressure)

3D in depth � TOF

� width of cathode readout strip

∆2θ = 0,469° ~ 6 mm

� lamellae height h = 7,9 mm at

window corresp. to ∆ϕ = 0,566°

resolution in 2θθθθ:

0,38° (FWHM)

resolution in ϕϕϕϕ:

0,665° (FWHM)

TOF resolution Anode spacing b = 15,6 mm 2,7 – 6,9 µs (FWHM)

Count rate per segment limited by coincident read-out of cathode and anode

2MHz @ 10% dead time

Count rate per readout ch limited by ASIC shaping time constant 333kHz @ 10% dead time

Parameter Design Value

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Detector Segments in Production at CDT GmbHcurrent capacity:

3 segments per week

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10B4C Coating for POWTEX

300 320 340 360 380 400 420 440 460 480 500

0,80

0,85

0,90

0,95

1,00

1,05

1,10

1,15

1,20

1,25

1,30

1,35

1,40

1,45

1,50

Model: y = P2*x

P2 0.00301 ±0.00002

Sch

ich

tdic

ke

Mic

row

aa

ge

[µ

m]

Schwingquarzwerte [relativ]

0 20 40 60 80 100 120 140 160 180 200 220 240

1,00

1,05

1,10

1,15

1,20

1,25

1,30

1,35

1,40

1,45

1,50

Sch

ichtd

icke

[µ

m]

Nr. Haubenblech

Waage

Quarz

Mittelwert

Coating at S-DHour neighbor and expert in

neutron guides

cathodes coated byFraunhofer Institut IST

coating thic

kness [µ

m]

sheet number

mic

ro b

ala

nce [µ

m]

quarz balance [∆f]

independent off-line measurementscorrelation

280 m2 coated ~ 40% of total area (700 m2)

µ-balancequarzmean

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POWTEX End-Cap Concept

� Two end-caps, covering 276° each

� 12°-segments with similar lamellae structure.

� Anode wires oriented in direction of the neutron path � avoid blind areas!

� Overall blind area < 5,8%

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POWTEX End-Cap, anode-wires oriented to sample

� End-cap engineering design and prototyping ongoing� 12°-Segment substructured in 5 submodules

� 10° inclination in ϕ � detection efficiency + avoid blind area!

� 10° inclination in 2θ � avoid blind area between submodules!

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POWTEX End-Cap

� Prototyping of sub-module 3 in autum

Challenges:

� 3D-Structure

� Sealed Aluminum housing

� Assembly procedures

� Contacting electrodes

� Production pre-series (four 12°-segments)

� Serial production in 2016 (full additional 42 segments)

POWTEX project finalization in spring 2017

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Electronic Signal Readout and DAQ

� Readout of individual channels through readout-ASIC CIPix-1.1, 60.000 ch

� Position identification and event reconstruction via coincidence identification in a local, module based FPGA, 2 Mio. volume elements (VOXELs)

� Data readout through Struck daisy-chained GBit optical link (SIS1104)

� One GBit optical link transmits at least 12,8 Mio. event mode data elements per second(64 Bit per event defined for POWTEX).

� More bandwith through segmentation into several readout areas

SIS1104 PCI Express Quad Optical Link Card(640MByte/sec)

Token Ring

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CDRS: 256-channel read-out for POWTEX, 2D-200 or 2D-300 detector

� Spartan-6 FPGA

� opt. Gbit interface

� 4-fold CIPix-ASIC interface

� Clock recovery and synchronisation to

global time

� 4ch ADC (60 MHz, 10 bit) � pulse

height analysis

� DDR-RAM on board

� LVDS interface

� Avago opt. I/O interface

� Digital-IO diagnostic sensor interface

� Powering via 48V/24V (galvanically decoupled)

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System capability and scalability of CDRS

� Token-Ring readout along the daisy chain� distribute bandwidth where it is needed

� Star-shaped clock distribution and backup communications channel

� System safety previsions:

� Three-fold concept to access for firmware upgrades

� Guaranteed access even with faulty firmware installed

� Three-fold clocking means

� Two-fold controls access

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CDT

CDTCASCADE Detector

TechnologiesGmbH

• Neutron Detectors

• Readout Electronics

• Complete Systems

• 10B Coatings

since 2006a university spin-off dedicated to

neutron detector technology

CDT GmbHHans-Bunte-Str. 8-1069123 HeidelbergGermany

www.n-cdt.com

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CDT CASCADE Detector Technologies GmbH� Founded in 2006 as spin-off of Physikalisches Institut Heidelberg

� Focus: 10B based area detectors for thermal and coldneutrons as complete system solutions withelectronics and software

� JALOUSIE detector, the alternative for 3He PSDs �

large areas, medium resolution � POWTEX

� CASCADE 2D-200 – high rates GEM-based solution with extraordenary

contrast of 105. � expansion to 2D-300

� CASCADE-MIEZE – special variation to resolve 1MHz intensity

variations

� CASCADE-BM position sensitive Beam Monitors

� UCN detectors

� ASIC and FPGA-based multi-channel readout electronics

� Customers: FRM-II, FZJ, ESS, PSI, ILL, KIT (IBR-II), IHEP (CSNS, China),

KEK & JAEA (Japan) via REPIC, KACST (Saudi Arabia),

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CDT Business Resources

� Equity capital: currently ~ (190 + 100 + 100) TEuro

� Current human resources:

10 FTE with additional ext. engineering capacities, further buildup ongoing

� Company premises: > 600m2 for lab-, production- and office space,

� High throughput, large area 10B4C coating facility at hand (~ 2 m2/day)

(cooperation with S-DH), metallic Boron coating

The 10B-based Jalousie Neutron Detector

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