Detectores de tempo de voo RPC em HADES. Performance em 1.25 AGeV

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Antônio Gabeira Wagner
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1 Detectores de tempo de voo RPC em HADES. Performance em 1.25 AGeV A. Blanco On behalf of HADES RPC Group Sixth framework programme

2 HADES RPC Group GSI D. Gonzalez W. Koenig LIP A. Blanco N. Carolino O. Cunha P. Fonte L. Lopes A. Mangiarotti USC D. Belver P. Cabanelas E. Castro J.A. Garzón G. Kornakov M. Zapata IFIC-Valencia J. Diaz A. Gil A. Pereira C. Silva C.C. Sousa C. Franco L. Silva Current and former members

3 Outlook - O que é uma câmara de placas resistivas (RPC). - A experiência HADES. - O detector de tempo de voo (TOF) baseado em RPCs para a experiência HADES. - Performance intrinseca. Resolução em tempo e posição. - Resolução de sistema. Eficiência e resolução em tempo.

4 Câmaras de placas resistivas (RPCs) E Gás gap Área sensível Material resistivo Material condutor ou material resistivo R&D em RPCs Medida de tempo: [NIMA ] [IEEE ] Grande área: [NIMA ] Medida de tempo e posição: [NIMA ] Características principais Eficiência 75% (0.3mm) > 99% (4 gaps). Resolução temporal 50 ps σ. Não têm resolução em energia. Possibilidade de medir a posição.

5 Espectrómetro HADES A investigação das propriedades dos hadroes dentro do núcleo a densidades e temperaturas altas é uma dos principais objectivos da física nuclear actual. Nestas condições, modificações significativas de propriedades básicas dos hadroes (massa, largura de decaimento, etc) são esperadas. HADES => Alta aceitação, precisão e capacidade de contagem. TOF RPC Shower Magnet RICH MDC II MDC I MDC IV MDC III

6 Espectrómetro HADES Located at: www-hades.gsi.de Darmstadt, Germany.

7 As células de HADES mm x 4 gaps Mínimo para uma boa eficiência -Eléctrodos de alumínio e vidro (2 mm) Minimizar a quantidade de vidro=> Maximiza a capacidade de contagem - Materiais tolerantes ao aquecimento Electricamente isolado na totalidade Alumínio Vidro Molas & suporte mecânico HV & leitura do sinal

O sextante Colunas t 1 Filas t 2 Camada - 187 células/sextante distribuídas em 32 filas, 6 colunas e 2 camadas - 1116 células no

8 O sextante Colunas t 1 Filas t 2 Camada células/sextante distribuídas em 32 filas, 6 colunas e 2 camadas células no total tipos diferentes de células (comprimento, largura, forma) - Leitura feita nos dois extremos T = (t 1 + t 2 )/2 X = t 1 t 2

9 FEE and DAQ DAQ based on a 128 ch multihit TDC [TNS 58 vol , 1745] FEE based on Philips BGM1013 G = 35.5 db, BW = 2 GHz, NF = 4.5dB [TNS 57 vol , 2848]

10 R&D, validação de protótipos, construção e teste Financiado FCT Validação, 2003 Protótipo, 2005 Sextante completo, 2007 Financiado EU + FCT Construção, Teste, 2009 Instalação, 2010

11 Instalado e integrado no espectrómetro

12 Intrinsic RPC performance. Au AGeV First Au + Au test run in HADES (Aug 2011) Multihit environment <n> ~ 15 One Au + Au collision from HGeant Multiplicity/sector simulation package

13 Intrinsic RPC performance. Analysis Overlapped cells t 1 t 1 t 2 t 2 Time difference T = (t 1 +t 2 )/2 (t 1 +t 2 )/2 Time resolution σ t = σ( T)/ 2 Position difference X = V prop /2 [(t 1 -t 2 )/2 (t 1 -t 2 )/2] = V prop /2[X 1 -X 2 ] Longitudinal position resolution σ x = σ( X)/ 2

14 σ t (ps) Intrinsic RPC performance. Time resolution Homogeneous time resolution < 100 ps <σ t > = 80 ps Sector 2 Row number σ t (ps)

15 σ t (ps) Intrinsic RPC performance. Time resolution S 1 < σ t Global > = 80 ps All channels have a resolution well below 100 ps < σ t > 81 ps S 2 80 ps S 3 80 ps S 4 79 ps S 5 82 ps S 6 78 ps Row number Out of a total of 1116 cell, 1112 are operative along with 2232 FEE

16 Beta Intrinsic RPC performance. Time resolution, P low, P high, π + π + <σ t >=70 ps P low energy <σ t >= 50 ps P high energy <σ t >= 64 ps p * q (Mev/c)

17 σ t (ps) Intrinsic RPC performance. Time resolution, multihit Multihit time resolution Neighbor in the same row Neighbor in the 4 th row Standard analysis Au AGeV Neighbor hit has no impact Sector 2 Distance (rows) to the neighbor hit

18 σ x (mm) Intrinsic RPC performance. Spatial resolution Homogeneous longitudinal position resolution < 10 mm σ 8.9 mm Sector 2 Row number σ x (mm)

19 σ x (mm) Intrinsic RPC performance. Spatial resolution S 1 < σ x Global > = 8.9 mm < σ x > 8.7 mm S mm S mm S mm S mm S mm Row number

20 System RPC performance. Analysis System efficiency MDC IV RPC? Shower MDC III Request a valid hit in outer MDC + shower MDC II MDC I target

21 System RPC performance. Efficiency <ε> ~ 0.93 include inefficiency due to double hits + inter-cell geometry Not include inter-column geometric inefficiency + disconnected cells

22 System RPC performance. Time calibration Individual cell system timing resolution at a level of 120 ps σ π S1 BC13 π + S1 BC13 TOF measured - TOF estimated TOF measured - TOF estimated Full sector system timing resolution at a level of 150 ps σ π S1 π + S1 TOF measured - TOF estimated TOF measured - TOF estimated

23 Beta System RPC performance. PID p * q (Mev/c)

24 Physics production run now!!

25 Conclusões RPC-TOF totalmente integrado no espectrómetro HADES e testado em feixe de Au + Au Resolução temporal uniforme <80> ps σ e eficiencia media ~93% em Au + Au, cumprindo os requisitos de desing Run de produção em andamento!!!

26 ΔT (ns) ΔT (ns) Intrinsic RPC performance. Time resolution, corrections. Position and charge information used to correct time < σ t > = 111 ps < σ t > = 104 ps X 1 position (ns) 1000 X 1 position (ns) < σ t > = 74 ps Q 1 (A.U) Q 1 (A.U)

27 σ t (ps) Intrinsic RPC performance. Time resolution, multihit Multihit time resolution All events Sector 2 Row number

28 σ t (ps) Intrinsic RPC performance. Time resolution, multihit Multihit time resolution n+1 n n-1 Row Selection of a standard hit (hit in overlapped cells) + at least other valid hit in the same row Second hit in the same row All events Sector 2 Row number

29 σ t (ps) Intrinsic RPC performance. Time resolution, multihit Multihit time resolution Selection of a standard hit (hit in overlapped cells) + at least other valid hit in a cell located beyond 4 rows Second hit in the same row All events Second hit in 4 th row Sector 2 Row number

30 <TOF> (ns) System RPC performance. Time calibration Different offsets of individual cells must be corrected to create a isochronous surface. Protons are used since covers almost all the detector surface with high statistics. Raw calibrated TOF from RPC TOF measured S2 BC Raw <TOF> positioned around 8 ns Row number

31 System RPC performance. Time calibration Different offsets of individual cells must be corrected to create a isochronous surface. Protons are used since covers almost all the detector surface with high statistics. Raw calibrated TOF from RPC TOF measured Momentum (p) and path length (L) from tracking Momentum cut at 0.9 GeV (avoid Mult.Scat) TOF estimated * = L/v = =L*m p /p *assuming all particles protons. ToF Calibration constant

32 System RPC performance. Time calibration Different offsets of individual cells must be corrected to create a isochronous surface. Protons are used since covers almost all the detector surface with high statistics. Peak due protons Calibration constant Failed mass hypothesis TOF measured - TOF estimated for one RPC cell

33 <TOF> (ns) System RPC performance. Time calibration Different offsets of individual cells must be corrected to create a isochronous surface. Protons are used since covers almost all the detector surface with high statistics. <TOF> after calibration Raw calibrated TOF from RPC TOF measured Momentum (p) and path length (L) from R-K S2 BC Momentum cut at 0.9 GeV (avoid Mult.Scat) TOF* = L/v = =L*m p /p *supposing all particles protons. ToF Calibration constant Row number

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