Progress report NeuLAND

Outline Short reminder about NeuLAND Timing RPC concept Open questions

- Impedance matching RPC prototype at GSI Next steps

Collaboration meeting in Göteborg, Sweden, October 13-16, 2008

T. Aumann, K. Boretzky, H. Emling, J. Hehner, M. Heil, K. Mahata, Y. Leifels, W. Prokopowicz, R. Reifarth, D. Rossi,

G. Schrieder, M. Elvers (Uni Köln)

NeuLAND

detection of relativistic neutrons in a ToF spectrometer reconstruction of projectile excitation energy exclusive measurements aiming for up to

E=30 keV at 1 MeV

Reactions with Relativistic Radioactive Beams

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

NeuLAND design goals

Time Resolution < 100 ps Position Resolution ~ 1 cm Excitation Energy Resolution ~ 100 keV x,y – Same Size as LAND 2 m x 2 m z – Length < 1 m Neutron Efficiency > 90% for 1-n hits Improvement of multi-n recognition

GSI HADES FOPICERN HARP ALICE

Timing RPC (Resistive Plate Chamber) concept

minimum ionizing particles

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

RPC principle

Fe (n ≈ 17 cm) Float Glass (~ 1012 /cm, n ≈ 12 cm)

GAS 85% C2H2F4 + 10% SF6 + 5% iso – C4H10Spacer (Fishing Line)

Kapton

n

p

Detect protons from hadronic showers in converter (Fe)NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Geometry of NeuLAND

total 140 m2 RPC approx. 104 channels each module hanging on slide

rod total weight app. 15

t

4×50 cm

200 cm

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Questions to be answered by tests with prototypes

Number of gaps

Material for high voltage layers

Impedance matching by

- adjusting the geometry (width of anode stripes, ...)

- impedance matching with electronics

Cross talk (distance between stripes)

Differential or single ended readout

Handling of material (e.g. large glass plates ...)

Mechanical stability

...

Prototypes from FZ Dresden-Rossendorf and GSINeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

GSI prototype

active area:

400 x 200 mm²

number of gaps:

8 (variable)

thickness of glass plates:

0.5 mm

gap size: 300 µm, distance holder: fishing lines

anode from 4 mm thick iron plate, strip width: 25 mm

outer electrodes: 2mm thick iron plates

electrode material: graphite spray (OKS 511)

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Pictures

Anode structure

Full assemblyHV electrode (carbon layer)

Isolation with KaptonNeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Problem: Impedance matching

refl

ecti

on

[d

B]

frequency [GHz]

tran

smis

sio

n

[dB

]

Small signals are expected. Measured impedance is 9.5 ⇔ preamp 50 Impedance matching will improve signal amplitude and shape.Measurements with network analyzer show large reflections.

50%

10%

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Impedance matching with transformers

10Ω

50Ω8.2pF1.5pF

ano

de

strip

pre

am

p

refl

ecti

on

[d

B]

10%

1%

frequency [GHz]

Good transmission for wide frequency band!

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Impedance matching with transformers

Transformers

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Results of impedance matching with transformers

refl

ecti

on

[d

B]

frequency [GHz]

tran

smis

sio

n

[dB

]50%

10%

Transmission improved but not for all frequencies!NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Next steps

Continue network analyzer tests

Application of gas and HV

Measurement with source / cosmics

Determination of cross talk etc.

Investigate readout possibilitiessingle ended FOPI preamp cards

differential read out (PADI?)

HADES like single ended read out

other developments?

Test with electron beam

NeuLANDintroduction

RPC concept

Open questions

RPC prototype

Impedance matching

Outlook

Impedance matching

Cable

Pin

Begin RPCEnd RPC

About 9.5 Ohm Impedanceinside RPC

Measured impedance is 9.5 This will cause problemsin connection with usual 50 preamplifiers.

NeuLAND working group

FZ Dresden-Rossendorf:FZ Dresden-Rossendorf: D. Bemmerer, A. Wagner, D. Yakorev

GSI, Darmstadt:GSI, Darmstadt: T. Aumann, K. Boretzky, H. Emling, M. Heil,

K. Mahata, Y. Leifels, W. Prokopowicz, R. Reifarth, G. Schrieder,

ISS, Bucharest:ISS, Bucharest: M. Haiduc, C.M. Ilie, M. Potlog

Jagellonski University, Krakow:Jagellonski University, Krakow: R. Kulessa

Johann Wolfgang Goethe Universität, Frankfurt:Johann Wolfgang Goethe Universität, Frankfurt: J. Stroth

Johannes Gutenberg-Universität, Mainz:Johannes Gutenberg-Universität, Mainz: J.V. Kratz, D. Rossi

KVI, Groningen:KVI, Groningen: Catherine Rigollet

SINP, Kolkata: SINP, Kolkata: S. Bhattacharya, U. Datta Pramanik

University Cologne:University Cologne: M. Elvers, A. Zilges

University of Santiago de Compostela:University of Santiago de Compostela: H. Alvarez-Pol,

J. Benlliure, E. Casarejos

Pictures

Anode structure

NeuLANDintroduction

RPC concept

RPC prototype

Open questions

Impedance matching

Outlook

Pictures

Isolation with KaptonNeuLANDintroduction

RPC concept

RPC prototype

Open questions

Impedance matching

Outlook

Pictures

HV electrode (carbon layer)

NeuLANDintroduction

RPC concept

RPC prototype

Open questions

Impedance matching

Outlook

Pictures

Full assembly

NeuLANDintroduction

RPC concept

RPC prototype

Open questions

Impedance matching

Outlook