GSI, Si microstrip detectors for R3B – general concept and prototypes O. Kiselev Gesellschaft für Schwerionenforschung, Darmstadt Institut für Kernchemie, Johannes Gutenberg Universität Mainz

GSI, Primary Beams /s; GeV/u; 238 U 28+ Factor over present in intensity 2(4)x10 13 /s 30 GeV protons /s 238 U 73+ up to 35 GeV/u up to 90 GeV protons Secondary Beams Broad range of radioactive beams up to GeV/u; up to factor in intensity over present Antiprotons GeV Cooled beams Rapidly cycling superconducting magnets Key Technical Features Storage and Cooler Rings Radioactive beams e – A collider stored and cooled GeV antiprotons The GSI Future Project FAIR UNILAC SIS FRS ESR SIS 100/300 HESR Super FRS NESR CR RESR

GSI, Physics at R3B Knockout Shell structure, valence-nucleon wave function, many-particle decay channels unbound states, nuclear resonances beyond the drip lines Quasi-free scatteringSingle-particle spectral functions, shell-occupation probabilities, nucleon-nucleon correlations, cluster structures Total-absorption Nuclear matter radii, halo and skin structures Measurements Elastic p scattering Nuclear matter densities, halo and skin structures Heavy-ion induced Low-lying transition strength, electromagnetic single-particle structure, astrophysical S factor, excitationsoft coherent modes, giant dipole (quadrupole) strength SpallationReaction mechanism, astrophysics, applications: nuclear-waste transmutation, neutron spallation sources Projectile fragmentation, Equation-of-state, thermal instabilities, multifragmentation structural phenomena in excited nuclei, g-spectroscopy of exotic nuclei

GSI, R3B – experimental setup DSSDs for heavy ion and detection of light (p, ) recoils

GSI, Solid State Detectors in HEP and Nuclear Physics  One of the most often used technology for the tracker systems  Very high position resolution, high dynamic range, precise E  Compact, X and Y coordinates from one plane (strips and pixels)  Vacuum compatible  Industrial support

GSI, HEP - CMS 10 7 channels in the inner pixel detector No  E, low dynamic range

GSI, R3B recoil system – first design Very compact design, barrel-like, first layer of DSSDs with radius of 2.5 cm, thickness 100  m, pitch 100  m, energy resolution is 50 keV (FWHM); second layer – radius 5 cm, thickness 300  m, pitch size 100  m, energy resolution is 50 keV (FWHM) System in vacuum 90k readout channels Low material budget liH 2 target inside the recoil system

GSI, R3B recoil system and calorimeter Complex mechanical structure Two systems must work together – synchronization, common DAQ Alignment is difficult Cross constrains

GSI, R3B recoil detector prototype  DSSDs, 300  m thick, 41 × 72 mm 2  strip pitch 100 m  Energy resolution – 50 keV for 5.5 MeV -particles  Dynamic range – 100 keV - 14 MeV  1024 readout channels  FE ASICs – VA64HDR9a (64 ch, very good linearity)  Multiplexed output  Designed to work in vacuum (total power dissipation < 3 W/detector) AMS – like design

GSI, GSI readout board SIlicon DEtector REadout MOdule (SIDEREM)- J. Hoffmann, N. Kurz, W. Ott 3 fast 12 bit ADCs, pedestal suppression, processing by DSP Conversion + processing ~ 100 µs Interface to GSI DAQ via SAM5/GTB

GSI, Pedestals and noise level Typical pedestals are 5-10% of the 12-bit range,  = 2-3 ADC counts

GSI, Tests under realistic conditions  Tested with cosmics, -source, 12 C beam with E = 350 MeV/u, + lighter fragments  S/N ratio 10 for MIPs, good separation between the isotopes (E)  August 2006 – 4 detectors with the readout used for S271 experiment at FRS  Mounted in vacuum (no active cooling), remote bias and temperature control MIPs

GSI, Energy loss and cluster width 20 Mg beam,  E measured by S side Cluster width vs ion charge Energy range up to 16 MeV (K side) and 23 MeV (S side)

GSI, Tracking of protons and ions Profile of fragmentation 20 Mg-> 18 Ne+p+p Proton-proton correlations vertex distributions along the beam Vertex precision ~100 µm, position resolution for heavy ions ~15µm

GSI, Si tracker for Cave C experiments  Frame for mounting of 5(6) detectors  Target wheel with a step motor 4 detectors for protons, one – for heavy ions

GSI, Next realistic test and prove of feasibility Everything is inside a vacuum chamber inside a Crystal Ball (160 CsI crystals) 5 experiments between May’07 and May’08

GSI, Optimization of the system concept and detector performance  MC simulations including: support frames and FEE boards  CAD design of the whole system (Si tracker + calorimeter)  Sensor geometry – strip pitch, thickness, strip orientation  New type of DSSDs – for example – self-triggering stripixel (single-sided 2D detectors)??? Separation energy resolution for the QFS reaction 12 C(p,p’) with E = 700 MeV/nucleon Compatible with the magnetic spectrometers Time line: end of 2008 – final design, start of mass production – beginning of 2009, start of operation – 2010

GSI, R&D – sensor geometry August’07 – 20 different DSSDs should be available for the tests Designed in collaboration with PTI, St. Petersburg Supported by INTAS - GSI-INTAS Call 2006 (only one proposal from NUSTAR)

GSI, Open questions Precise mechanical structure with 1060 nm laser, absorption length ~2 mm, fiber 1-2 mm above the sensor, spot size 20 – 100 µm, steps 20 – 30 µm Alignment (and monitoring of positions) inside the calorimeter – laser system? cosmics? Trigger/time stamping  different ASIC? Reduction of conversion/processing time Mechanical design, electronics Characterization of the detectors, positioning on ladder Very limited manpower and funds  synergy with CBM, PANDA, SPIRAL2 is very useful

GSI, Organization of the Working Group  13 institutes from 7 countries  Close collaboration with other WGs: EXL/NUSTAR Si detector, R3B/EXL Calorimeter and NUSTAR DAQ/FEE  Participation in Synergy Group for Si Detectors (NUSTAR, SPIRAL2, LNL)  Meetings twice per year  list joined with EXL, 21

GSI, Summary  Many Si trackers are built but practically no one project was interested in precise E resolution  There is a first concept of R3B recoil system, it’s feasibility will be proven soon  First prototypes are tested in realistic conditions, shown very good performance  New prototypes (including thin) should be soon available, still few open questions  Preproduction prototypes – end of 2008, start of operation with the first radioactive beams available at FAIR