R. Lipton Vertex ‘98 Santorini, Greece The D0 Silicon Microstrip Tracker (D0SMT) Outline  Design  Detector Studies Coupling capacitors Radiation Damage LASER tests  Electronics and readout  Mechanical Assembly  Production Testing  Summary and prospects  Installation in the spring of 2000

R. Lipton Vertex ‘98 Santorini, Greece D0SMT Components Major SMT Subsystems Single Sided Ladder (3 chip) Double Sided 2 o Ladder (9 chip) Double Sided 90 o Ladder (6 chip) H Disk (SS back-to-back) F Disk (DS)

R. Lipton Vertex ‘98 Santorini, Greece Barrel/Disk Module

R. Lipton Vertex ‘98 Santorini, Greece H DISK Silicon IR = 94.5 mm, OR = 236 mm at wedge centerlineSilicon IR = 94.5 mm, OR = 236 mm at wedge centerline Readout mounts on outer silicon detectorReadout mounts on outer silicon detector Wedges alternate between two surfaces of a central cooling/support channelWedges alternate between two surfaces of a central cooling/support channel Effective stereo angle = 15 oEffective stereo angle = 15 o

R. Lipton Vertex ‘98 Santorini, Greece F Disk Silicon IR = 26 mm, OR = mm at wedge centerlineSilicon IR = 26 mm, OR = mm at wedge centerline Readout mounts outboard of silicon, which allows disk to fit within a gap of 8 mmReadout mounts outboard of silicon, which allows disk to fit within a gap of 8 mm Wedges alternate between two surfaces of a central cooling/support channel (beryllium)Wedges alternate between two surfaces of a central cooling/support channel (beryllium) Effective stereo angle = 30 degreesEffective stereo angle = 30 degrees p-side Trace angle = -15 o with respect to wedge centerline Pitch = 50 μmp-side Trace angle = -15 o with respect to wedge centerline Pitch = 50 μm n-side Trace angle = +15 o with respect to wedge centerline Pitch = 62.5 μmn-side Trace angle = +15 o with respect to wedge centerline Pitch = 62.5 μm

R. Lipton Vertex ‘98 Santorini, Greece Capacitor Studies  In a double sided detector with grounded electronics, coupling capacitor breakdown will limit the lifetime of the detector.  Studies  Eliminate “black hole” effect in the SVX chip by bypassing parasitic transistor at the input (see VTX ‘96)  Effect of wirebonding on capacitor breakdown  5-10% of capacitors fail at V after bonding (normally V bd =140V) on SS detectors  No excess failures see on DS detectors with PECVD layer

R. Lipton Vertex ‘98 Santorini, Greece n-side Capacitor Studies  When electronics are connected to the n-side of a detector with shorted capacitors we see an anomalous current from the amplifier input  Current is reduced when electronics is disconnected  Effect seen on n-side only  Caused by forward bias of the p-stop n junction

R. Lipton Vertex ‘98 Santorini, Greece n-side Capacitor Studies

R. Lipton Vertex ‘98 Santorini, Greece Irradiation Studies  Expect ~1 Mrad exposure for the inner layer per 4fb 1  Irradiation with  8 GeV Protons from the Fermilab booster  1 MeV Neutrons (Lowell Mass.)  Study  Evolution of deletion characteristics  Performance of detector and electronics

R. Lipton Vertex ‘98 Santorini, Greece Irradiation Studies Cluster size

R. Lipton Vertex ‘98 Santorini, Greece Irradiation Studies noise

R. Lipton Vertex ‘98 Santorini, Greece H Disk Irradiation Depletion voltage (volts) N eff (10 11 /cm 3 ) Neutron fluence (10 13 /cm 2 )

R. Lipton Vertex ‘98 Santorini, Greece Neutron Studies Detector Studies using ~1 MeV neutron source

R. Lipton Vertex ‘98 Santorini, Greece Irradiation Studies LASER Plateau

R. Lipton Vertex ‘98 Santorini, Greece Detector Production  Five detector types - 3-chip, 9-chip, 6-chip, F wedge, H wedge.  All radiation testing complete  laser and cosmic ray studies  Measure in-situ rise times  charge sharing distributions  Probe testing  100 V capacitor breakdown test on each channel  CV or alpha test to measure depletion  IV Test  Spot checks on  Interstrip resistance  Coupling capacitance  Strip currents

R. Lipton Vertex ‘98 Santorini, Greece Micron Detector Delivery Needed for schedule Needed for schedule

R. Lipton Vertex ‘98 Santorini, Greece Readout System

R. Lipton Vertex ‘98 Santorini, Greece D0SMT - Electronics  SVXII Chip - done and tested  Most issues involve bypassing and clock quality  Needs careful hybrid(HDI) design  HDIs - delivery pacing production  Single layer flex 4 mil pitch, 2 mil vias  Cables:  low mass, good frequency response (53 Mhz), low attenuation, no reflections, no radiation of clock signal to the calorimeter, fits in the allowed space.  High impedance stripline  3 segments  low mass section of varying length  low mass fixed length  “high mass” high quality section  System tests underway now

R. Lipton Vertex ‘98 Santorini, Greece Where we were “burned”  HDI flex circuit - good prototypes but no good production circuits  Find reliable company (Dyconex)  pay extra $$$  Detector delivery - ordered detectors 2 years early but waited for BABAR, H1…  still a serious problem  Cables  low mass, high impedance striplines are difficult  pay extra $$$  But we are now in production and expect to be on schedule

R. Lipton Vertex ‘98 Santorini, Greece Mechanical Systems  Design Philosophy  Build planar assemblies (ladders, wedges, disks) precisely under (Zeiss) CMM  Use mechanical tolerances to determine ladder placement in barrel (~15  m)  Minimum Mass  Be support structures  Carbon fiber overall support

R. Lipton Vertex ‘98 Santorini, Greece Ladder Assembly

R. Lipton Vertex ‘98 Santorini, Greece Module Assembly

R. Lipton Vertex ‘98 Santorini, Greece

R. Lipton Vertex ‘98 Santorini, Greece Ladder Assembly  Match notches in Be support to posts in bulkhead  15 micron tolerance on Notched and posts  2 micron tolerances achieved in ladders Detector fiducials relative to beryllium notches Transverse offset from nominal (μm)

R. Lipton Vertex ‘98 Santorini, Greece Rise Time Studies Use LASER to excite SSD, Monitor preamp

R. Lipton Vertex ‘98 Santorini, Greece Production Testing  HDI Burn-in  Encapsulation  HDI Spot-check  Ladder assembly  Ladder Spot-check  Ladder repairs  Ladder burn-in  LASER Test  Insertion into detector

R. Lipton Vertex ‘98 Santorini, Greece Laser Testing Channel uniformity

R. Lipton Vertex ‘98 Santorini, Greece Laser Testing Channel Gains

R. Lipton Vertex ‘98 Santorini, Greece Ladder and HDI

R. Lipton Vertex ‘98 Santorini, Greece Summary  We have achieved:  low mass flex/beryllium hybrids  SVX II chip, 53 MHz readout  Minimal dead area  Precise construction  A workable double sided design for “moderate” radiation doses  Now we just have to build another 787,968 channels