Thought on SCIPP’s Participation in SiLC Test Beam Activities SiLC Meeting Barcelona, Spain (by telephone) December 19 2006 Bruce Schumm

What might we want to demonstrate by 2011 (partial list)? Power Cycling Long-ladder operation / system noise Efficiency vs. occupancy for long ladder Point resolution (vs. incident angle) Timing resolution Rate capability / readout scheme Propagation effects (distance from readout chip) * Item in green can only be assessed with high-energy test beam, but some others might benefit

Faking the Magnetic Field Michael Young, UCSC Resolution Track Angle Different track angles for 5T field (B-Field) or 180 mrad tilt with no B-field (Tilted).

Faking the Magnetic Field Michael Young, UCSC Resolution Magnetic Field (T) Different B-Fields (B-field) or detector tilt to simulate Lorentz angle (Tilted)  Do we need high-field test beam facilities?

SiLC will want to develop both new sensors and new readout It would be best to test new sensors with established readout and new readout with established sensors IDEA: Might SCIPP be able to provide assemblies (ladders) of establihsed sensors borrowed from other experiments for readout groups to use in testing their electronics? Problem: ILC optimization points to Long Ladders – must worry about parallel noise Long Shaping Time – must worry about leakage current High Resolution – must worry about strip/readout pitch

Helmuth Spieler’s Rule of Thumb for Equivalent Noise Charge Qn (p 148 of his Semiconductor Detector Systems): where: Id = detector leakage current Rp = parallel resistance (bias resistance) C = effective capacitance = shaping time Ideally, Qn < 2% of a min-i signal, or roughly 500 e-. At  = 2 sec, this limits Id to be less than ~ 10 nA and Rp to being greater than ~ 5 M, where individual bias resistors in the ladder add in parallel.

Existing Sensors 7 m resolution goal suggests ~50 m is correct scale for readout pitch LHC sensors tend to have larger (~100 m pitch) Tevatron upgrade vertexing inner layers have correct pitch D0 L2-5 sensors have 30 m pitch with 60 m readout CDF L00 sensors have 25 m pitch with 50 m readout

D0 Layer 2-5 Sensors Very large (~ 1000) supply Characterization data-sheets available Leakage currents ap-pear acceptable (spec is ~ 10 nA/strip; actual is much better) Polysilicon bias resistor rather small

CDF Layer00 Sensors More limited supply (???; have 20 in hand, but can only keep 10) Will do characterization ourselves this winter Leakage current spec OK Polysilicon bias resistor OK (Both Rb and Ileak are a little marginal, but should be fine for initial testbeam

So, CDF L00 detectors looks possible, but only one at a time… “Long” ladder is one 8cm sensor and a big discreet capacitor? Or: build long ladder by bonding a single 8 cm sensor to low-leakage, large-bias-resistor, coarse-pitch detectors (GLAST would be a possibility) to allow for antenna, transmission line effects Or: identify more appropriate existing sensor (?)

Particularly for long ladders, angle of incidence can really matter  I believe it to be very important that we be able to rotate ladder around axis perpendicular to the beamline

What might SCIPP bring to a testbeam run for the mutual benefit of SiLC? (enlightened self-interest) Long (or “long”) ladder with well-understood sensor?  would need to develop front- and back-end specs for those wishing to plug electronics into it and to read out the electronics Alternatively, could produce several and ship them? Rotating jig for SCIPP ladder(s)? Would depend on availability of funding (“Supplemental” proposal is pending)