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 NeuLAND introduction 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 FOPI CERN HARP ALICE Timing RPC (Resistive Plate Chamber) concept minimum ionizing particles NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

RPC principle Fe ( n ≈ 17 cm) Float Glass (~  /cm, n ≈ 12 cm) GAS 85% C 2 H 2 F % SF 6 + 5% iso – C 4 H 10 Spacer (Fishing Line) Kapton n p Detect protons from hadronic showers in converter (Fe) NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Geometry of NeuLAND total 140 m 2 RPC approx channels each module hanging on slide rod total weight app. 15 t 4×50 cm 200 cm NeuLAND introduction 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 GSI NeuLAND introduction 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) NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Pictures Anode structure Full assembly HV electrode (carbon layer) Isolation with Kapton NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Problem: Impedance matching reflection [dB] frequency [GHz] transmission [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% NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Impedance matching with transformers 10Ω 50Ω 8.2pF1.5pF anode strip preamp reflection [dB] 10% 1% frequency [GHz] Good transmission for wide frequency band! NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Impedance matching with transformers Transformers NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Results of impedance matching with transformers reflection [dB] frequency [GHz] transmission [dB] 50% 10% Transmission improved but not for all frequencies! NeuLAND introduction 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 possibilities single ended FOPI preamp cards differential read out (PADI?) HADES like single ended read out other developments? Test with electron beam NeuLAND introduction RPC concept Open questions RPC prototype Impedance matching Outlook

Impedance matching Cable Pin Begin RPC End RPC About 9.5 Ohm Impedance inside RPC Measured impedance is 9.5  This will cause problems in 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 NeuLAND introduction RPC concept RPC prototype Open questions Impedance matching Outlook

Pictures Isolation with Kapton NeuLAND introduction RPC concept RPC prototype Open questions Impedance matching Outlook

Pictures HV electrode (carbon layer) NeuLAND introduction RPC concept RPC prototype Open questions Impedance matching Outlook

Pictures Full assembly NeuLAND introduction RPC concept RPC prototype Open questions Impedance matching Outlook