1. Beam detectors in Au+Au run and future developments - Results of Aug 2012 Au+Au test – radiation damage - scCVD diamond detector with strip metalization in Apr 2012 - Detector calibration for the DST production for Apr2012 experiment - Future developments: - pion beam - CBM/HADES at SIS100 and CBM @ SIS300 Jerzy Pietraszko a,W. Koenig a, S. Spataro b for the HADES Collaboration a GSI Helmholtz Centre for Heavy Ion Research GmbH Planckstrasse 1, D-64291 Darmstadt, GERMANY b Universita' di Torino - Dipartimento di Fisica Generale, Torino, ITALY HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

2. 2 Radiation hardness study with Au beam (Aug11) reminder Dismounted Start detector: Beam spot: 0.8x1.6mm 2 HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

3. 3 Radiation hardness study with Au beam (Au 2011) reminder Total dose during 5 days measured in the Start detector 1.9 x 10 11 Au ions + 30 % DAQ off + 30 % beam times in 2010  3.04 x 10 11 Au ions / mm 2  total absorbed dose: 7.9 Grad inner segments outer segments ADC spectra (at 60 V) Pu239 - Am241 - Cm244 (vacuum) 5.157 MeV - 5.486 MeV - 5.804 MeV HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

4. Radiation hardness study with Au beam (Au 2011) signal characteristics  Diamonds behave differently being irradiated by Au beam and by Alpha particles Simple model: capacitor 0.4mm x 0.4mm at 100V  charge deposited: 7.4 pC Au ion  charge deposited: 1.8 pC  effective field reduced HV [V] HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

5. 5 Radiation hardness study with Au beam - amplitude reduction Threshold characteristics (Aug11): cut amplitudes lower than 35mV Analog signals, Au beam, HV: 100V Amplitude; 94 mV  After 3.04 x 10 11 Au ions /mm 2 5% of signals below 35 mV (7.9 Grad)  Amplitude reduction by a factor of 2.7 HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

6. 6 The start detector for Apr12 Main improvement: Double-sided multi-strip diamond based sensor for HI (16 channels on each side) As planned: - diamond sensor, 16 stripes on each side -holder which allows the detector to be moved -beam spot: ellipse As produced: - 16 stripes on each side -strip width: 200µm -gap: 90 µm -det. thickness about 60 µm  large field inhomogeneity HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

7. 7 The start detector for Apr12 readout electronics Main improvement: fast analog amplifier (x 10) installed to compensate for the reduction of the signal helped a lot to compensate for the reduction of the signal due to large field inhomogeneity caused by too wide gaps between strips !!!! Analog signals, strip detector (Start X) one channel, Au beam, HV: 100V, Amplifier: x10,  huge signal amplitude variations: 0 – 350 mV (threshold set to 13mV ) Analog signals of the “old” diamond (used in aug11) Au beam, HV: 100V  constant signal amplitude: 100 mV HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

8. 8 New start detector for Apr12 Time res of the StartX, Apr12, beam data, day 097 (Start X vs Veto ch0, not divided by 1.4) Intrinsic time resolution: Side X better than 60 ps, Side Y better than 70 ps 4% 0.6% HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

9. 9 The start detector for Apr12 Detector efficiency, Apr12, beam data, day 097 8mm Start detector Veto detector HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

10. 10 Calibration of the start detector for Apr12 (Stefano Spataro) - Calibration is based on reconstructed pions in the META - Each start detector channel is calibrated separately - Calibration parameters prepared for each run  example for Aug11 the same procedure used for Apr12 data Strip 1Strip 2Strip 3Strip 4 Strip 1Strip 2Strip 3Strip 4 Before calibration After calibration HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

11. 11 Start detector analysis improvement for Apr12 – high rate experiments T0 determination -Increased probability at higher beam intensity -Significant effect coming from micro-spill structure  wrongly assigned T0 in Time-of-Flight determination procedure (below 10 %) SIS 18/100 crew is aware of this problem. Solution is needed for FAIR. Start X Start Y Veto Tof and RPC hits HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

12. 12 Start detector analysis – T0 determination -Use Start X and Start Y (both sides of the Start detector) -Use three fastest particles in RPC/TOF from hit level (before tracking !!!) to define the reaction (7 ns ToF of fastest particles)  wrongly assigned T0 in Time-of-Flight determination procedure ToF of the three fastest particles in TOF and RPC, ToF normalized to the same path length  2-3 ns precision Calibrated StartX – StartY  150ps sigma Improvement: old method (first Start Hit taken) vs new approach (T0 selected based on TOF/RPC hits)  method works correctly BUT: Works only if the time separation of beam particles is greater than 3 ns !! Implemented, ready to be used in DST gen1. HStart2Hit::getCorrFlag() cases: 0. StartX 1. StartY 2. Start X and Y (mean) HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

13. 13 Start detector analysis – problem with T0 Limitations of the method based on TOF/RPC and Start: Works only if the time separation of beam particles is greater than 3 ns !!  We will mark such cases in StartHitFinder (more than 1 hit within 3ns window) by adding an additional flag: 3 or -2 Still wrongly determined T0. Event selection: At least 5 protons in RPC with time larger than 1.5 ns (10 -4 ) Plots from P.Tlusty Ultimate method should be based on fully reconstructed tracks (G. Kornakov) Reconstructed T0 from all tracks in single event compared to T0 from the Start detector Fit result based on 1/sqrt(N) contribution from tracking and constant contribution from Start detector. σ(Start)=60ps To be implemented in HYDRA – high level analysis. HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

14. 14 Outlook (1) 1.Start detector for pion beam  segmented, high rate, diamond detector for MIPs. Diamonds as timing detectors for minimum-ionizing particles.... J.Pietraszko et al.. NIM A 618 (2010) 121 - 123. - Small size detector ready (4.7 mm x 4.7 mm). 10 mm x 10 mm – needed. - Time resolution should be improved from 110ps  50ps 2.Start detector for heavy ions  low quality metallization reduce det. efficiency – metallization has to be improved 3. Start detector for FAIR (HADES/CBM)  high rate experiments (10 9 HI beam particles) : decent segmentation + fast readout electronics (TRB3) Real Time Conference (RT), 2010 17th IEEE-NPSS HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

15. 15 Outlook (2) 4. High rate, high charge resolution measurement (Diamond, ECal, MDC,....) Large jitter of the integrator width (charge) due to high gain for low frequency noise After walk correction via leading edges:  Charge Resolution: 0.17 % HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.

16. 16 Thank you HADES Collaboration Meeting XXV, GSI, Darmstadt, 19-22 November 2012.