1. RPC upgrade for the HADES Tracking: MDC e -,e + identification with RICH- TOF/PreShower  0.4 GeV/c TOF is not sufficient- Pre-Shower p,  identification TOF-Tracking RICH MDC I/II coils

2. HADES’2003 TOF walls Outer TOF wall  >45 0 : 6 * 64 scintilator rods. TOF & position measurement  t : 120 ps,  x  2cm dE/dx measurement TOFINO Pre-Shower target Inner TOF wall  <45 0 : 6 * 4 scintilator paddles TOF measurement  t : 550 ps, no  x dE/dx measurement

3. p [MeV/c] Fraction of identified π + π + p fake fake π + other Inner TOF performance in C+C@2AGeV TOF [ns] Hadron id Lepton id q*p [MeV/c] RICH Pre-Shower Pion id double elec. hits no e/  separation by TOF : only with RICH+PreShower:  e+  for p<0.4 GeV/c ) TOF measurement limited to light systems (C+C)-double hits! no spatial resolution (pair analysis!)  /p separation for p< 1 GeV/c no K/  separation

4. Resistive Plate Counters for HADES Requirements for an RPC TOF detector for HADES: -Adequate granularity (HI collisions)- double hit probability<10% 6 sectors: 660 counters with 4 gaps (99% efficiency) -Time resolution below 100 ps : e/  separation for p<0.4 GeV/c (95% CL)  /p separation  /K separation for p<1.GeV/c (99% CL) -Space resolution around S=3 cm 2 electron pair analysis. -Stable behaviour at rates of few hundreds of Hz/cm 2 and in presence of high ionising particles high resistive glass (2.5mm thick) Negligible cross talk Isolated detector modules

5. Physics cases for new TOF High intenisty pion beams: o continuation of HADES pion programme : dielectron production in  - p (proposal S262):  - p  e+e-n,  - p  R   /  n (  /  coupling to S 11 (1535), D 13 (1520)) Beam intenisty I  - = 4*10 6 /spill(4s) to exclusive  + p reactions:  + p  R   /  p  + @1.3 GeV/c „subthreshold omega”-  „deflation” D 37 (1930),F 37 (1930) @ 2.35 GeV/c electromagnetic   0 e + e - form-factor (VDM „puzzle”) Beam intenisty I  + =5.2*10 6 /spill (4s) @1.3 GeV/c, 3.6*10 6 /spill@2.35 GeV/c p/  separation at high momentum o @ 1.3 GeV/c Recoiless  production in  - Pb collisions (in-medium effects) o Weak-electromagnetic structure of hyperons  + p  K +  +  K + Xe + e - (1.8 GeV/c) Kaon tagging ! Increase of pion beam intensity  physics. OZI rule violation in pion and proton induced reactions.  identification via kaon decays

6. Physics cases with new TOF HI collisions above C+C @1-2 AGeV HI collisions at new SIS facility C+C @ 8AGeV same detector geometry Similar LVL1 rate Slightly higher p/  + momenta in forward TOF 15k  /5 day run

7. RPC geometry Top view of one sector electron identification  > 0.9 even for 1 AGeV Au+Au Rate < 700 Hz/cm 2 for Au+Au 10 8 ions/spill

8. RPC prototype performance @2AGeV C+C Gas admixture: 98.5% C 2 H 2 F 4 + 1% SF 6 + 0.5 isoC 4 H 10 160cm long 4 gaps 0.3cm gap Cross talk < 0.4%

9. RPC read-out Front-end on detector (preamp, shaper,discriminator) – commercial components-tested in beam 2 time read-out/ module (1320 TDC channels) 1 charge /module (660 ADC or Time over Threshold)  CAEN 132 channel multi-hit TDC („plug and play”)  F1-TDC multi-hit digital TDC + fast internet controler (development)  GSI TAQUILA (development) Proposals in evaluation by HADES DAQ (decision about prototypes in February 2003)

10. Project organisation and cost estimate Detector construction: LIP Coimbra, Univ. Santiago, INR Moscow Front-end :Univ. Santiago, CIEMAT-Madrid Digitial read-out and DAQ: GSI, Univ. Giessen, Univ. Cracow 1 sector prototype scheduled on autumn 2004 Detector mat.100 k€ Machining80 K€ 180 k€ Det.mechanics30 k€ LV,HV35 k€ Gas system15k€ 80 k€ Front-end60 k€ Digitizers+DAQ120 k€ 180 k€ 440 k€ + 2Phd positions Investment: