Decay Spectroscopy at FAIR Using the Advanced Implantation Detector Array (AIDA) presented by Tom Davinson on behalf of the AIDA collaboration (Edinburgh – Liverpool – CCLRC DL & RAL) Tom Davinson School of Physics The University of Edinburgh

Presentation Outline Where? Why? How? When? Who? What next?

Cost –Approx €1000M –€650M central German government –€100M German regional funding –€250M from international partners Timescale –Feb German funds in budget –2007 start construction –2012 phased start experiments –2014 completion NUSTAR Super FRS Future facility 100 m GSI today SIS 100/300 UNILAC ESR SIS 18 HESR RESR NESR FAIR: Facility for Antiproton and Ion Research

NUSTAR: Nuclear Structure Astrophysics & Reactions Exotic (radioactive) beams formed by fragmentation, selected by separator. HiSpec :gamma spec DeSpec :decay spec LASPEC: laser spec MATS: Penning traps Stored beam (rings): EXL : hadron scattering ELISe : electron scattering AIC : antiproton scattering R 3 B: reactions

FAIR: Production Rates from FAIR CDR, section 2 Predicted Lifetimes > 100ns

r-process Nucleosynthesis along neutron-rich side of valley of stability via s-process and r-process s-process – Red Giants, long timescales, moderate n-flux nucleosynthesis close to valley r-process – Supernova type II?, timescales ~seconds?, high n-flux? nucleosynthesis far from valley equilibrium (n,  ) and ( ,n) reactions? n-capture until binding energy becomes small wait for  decay to nuclei with higher binding energy effect of neutron magic numbers – 82, 126? Require: nuclear masses (r-process pathway)  decay half lives (abundance along pathway)  -delayed neutron emission probabilities (abundance modification)

NUSTAR: DESPEC/HISPEC Note – this layout is so out of date …

DESPEC: Implantation DSSD Concept SuperFRS, Low Energy Branch (LEB) Exotic nuclei – energies ~ 50 – 200MeV/u Implanted into multi-plane, highly segmented DSSD array Implant – decay correlations Multi-GeV DSSD implantation events Observe subsequent p, 2p, , , ,  p,  n … decays Measure half lives, branching ratios, decay energies … Tag interesting events for gamma and neutron detector arrays

Implantation DSSD Configurations Two configurations proposed: a)8cm x 24cm “cocktail” mode many isotopes measured simultaneously b) 8cm x 8cm high efficiency mode concentrate on particular isotope(s)

Implantation – Decay Correlation DSSD strips identify where (x,y) and when (t 0 ) ions implanted Correlate with upstream detectors to identify implanted ion type Correlate with subsequent decay(s) at same position (x,y) at times t 1 (,t 2, …) Observation of a series of correlations enables determination of energy distribution and half-life of radioactive decay Require average time between implants at position (x,y) >> decay half-life depends on DSSD segmentation and implantation rate/profile Implantation profile  x ~  y ~ 2cm,  z ~ 1mm Implantation rate (8cm x 24cm) ~ 10kHz, ~ kHz per isotope (say) Longest half life to be observed ~ seconds Implies quasi-pixel dimensions ~ 0.5mm x 0.5mm

Silicon Detector Technology Current Technology Single, double-sided, resistive strip Thin Junctions p  m cf. ~ 0.4  m Integrated Components Coupling Capacitors Bias Resistors 3” & 4” Wafers Thicknesses ~ 20 – 1500  m Max. Area ~ 70cm 2 6” Wafers Thicknesses ~ 200 – 700  m Max. Area ~ 160cm 2 MSL type YY1 (LEDA) d.c. single sided 8 sectors, 16 strips/sector Strip Pitch 5mm Area 370cm 2 NIM A454 (2000) 350

Silicon Detector Technology contd. GLAST Large Area Telescope (LAT) Layers of silicon detectors interleaved with heavy-metal converters for > 20MeV  -rays Area ~80 m 2 ~10 6 channels integrated a.c. coupling and bias resistors series strip bonding >10000 wafers from Hamamatsu Very high quality: –Leakage current < 2.5 nA/cm 2 –Bad channels < 1/10,000 –Full depletion < 100 V 8.95 cm square Hamamatsu-Photonics SSD before cutting from the 6-inch wafer. The thickness is 400 microns, and the strip pitch is 228 microns.

AIDA: DSSD Array Design 8cm x 8cm DSSDs common wafer design for 8cm x 24cm and 8cm x 8cm configurations 8cm x 24cm 3 adjacent wafers – horizontal strips series bonded 128 p+n junction strips, 128 n+n ohmic strips per wafer strip pitch 625  m wafer thickness 1mm  E, Veto and up to 6 intermediate planes 4096 channels (8cm x 24cm) overall package sizes (silicon, PCB, connectors, enclosure … ) ~ 10cm x 26cm x 4cm or ~ 10cm x 10cm x 4cm Implantation depth? Stopping power? Ge  detector? Calibration? Radiation damage? Cooling? courtesy B.Rubio

AIDA: General Arrangement

ASIC Design Requirements Selectable gain MeV FSR Low noise keV FWHM energy measurement of implantation and decay events Selectable threshold< 0.25 – 10% FSR observe and measure low energy ,  detection efficiency Integral non-linearity 95% FSR spectrum analysis, calibration, threshold determination Autonomous overload detection & recovery ~  s observe and measure fast implantation – decay correlations Nominal signal processing time < 10  s observe and measure fast decay – decay correlations Receive (transmit) timestamp data correlate events with data from other detector systems Timing trigger for coincidences with other detector systems DAQ rate management, neutron ToF

Schematic of Prototype ASIC Functionality Note – prototype ASIC will also evaluate use of digital signal processing Potential advantages decay – decay correlations to ~ 200ns pulse shape analysis ballistic deficit correction

Representative ASIC Noise Analysis Minimise ballistic deficit shaping time >10x t r operate with  ~  s noise dominated by leakage current for I D > 10 nA Note – amongst other assumptions, we assume detector cooling

Design Study Conclusions 4’’ or 6” Si wafer technology? - integrated polysilicon bias resistors (15M  ) - separate coupling capacitors (require 22nF/200V+) Radiation damage mitigation measures essential - detector cooling required Noise specification (12keV FWHM) … “not unreasonable” Discriminator - low threshold ( 100nA - separate timing discriminator – higher threshold x1000 overload recovery ~  s achievable - depends on input pulse shape - optimisation requires more information

Virtex 4FX FPGA Power Supplies, Temperature+ voltage monitors and other components Fibre Driver (Laser) 16 ch ASIC 128 detector signals in; 1 data fibre out PPC (Unix) Ethernet physical interface ADC Readout Timestamp control FADC PSA ASIC Control Slow Control Data Output ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs ASIC 1 SS ADC 16 FADCs 16 FADCs (12 bit) 1 Sliding Scale ADC (14bit) per ASIC Front End Electronics (FEE) Concept courtesy Ian Lazarus, CCLRC DL

Pk Det & Mux Preamp + shaper low/high gain. (16 channels) Octal FADC (serial out) 12bit 50MHz (2 per ASIC) Control Logic Part of FPGA Sliding Scale Spectroscopy ADC 14bits 1 to 5us conv. Octal FADC (serial out) 12bit 50MHz (2 per ASIC) FEE Detail for One ASIC courtesy Ian Lazarus, CCLRC DL

Slow Control BUTIS Timestamps Data Output Switch PC Farm AIDA: System Concept courtesy I.Lazarus, CCLRC DL

AIDA Design Concept Detail of DSSSD detector layers and detector enclosure Beam courtesy Dave Seddon & Rob Page, University of Liverpool

AIDA Design Concept courtesy Dave Seddon & Rob Page, University of Liverpool AIDA instrumentation (beige) Heavy-metal shielding (grey)

AIDA: Current Status Edinburgh – Liverpool – CCLRC DL – CCLRC RAL collaboration - 4 year grant period - DSSD design, prototype and production - ASIC design, prototype and production - Integrated Front End FEE PCB development and production - Systems integration - Software development Deliverable: fully operational DSSD array to DESPEC Proposal approved EPSRC Physics Prioritisation panel meeting April 2006 Project commenced August 2006 Detailed specification development underway M0 – specification finalised and critical review Technical Specification release to project engineers January 2007 We are here!

AIDA: Resources & Tasks Cost Total announced value proposal £1.96M Support Manpower CCLRC DLc. 4.2 SYFEE PCB Design DAQ h/w & s/w CCLRC RALc. 3.5 SYASIC Design & simulation ASIC Production Edinburgh/Liverpoolc. 4.5 SYDSSD Design & production FEE PCB production Mechanical housing/support Platform grant support CCLRC DL/Edinburgh/Liverpool

AIDA: Workplan

AIDA: Project Partners The University of Edinburgh (lead RO) Phil Woods et al. The University of Liverpool Rob Page et al. CCLRC DL & RAL John Simpson et al. Project Manager: Tom Davinson Further information: Technical Specification: Comments on Technical Specification invited!

Acknowledgements This presentation includes material from other people Thanks to: Ian Lazarus (CCLRC DL) Steve Thomas (CCLRC RAL) Dave Seddon & Rob Page (University of Liverpool) Berta Rubio (IFIC, CSIC University of Valencia) Haik Simon (GSI)