Stavelet Update Peter W Phillips 29/07/2011

Serial Powering with a Stavelet Module: Recent Results Whilst single SP modules in the “chain of hybrid” configuration generally give good ENC results, double trigger noise results were previously disappointing. Several possible revisions made little difference: Adding capacitors across each hybrid Using external control of ABCN-25 shunts However if one uses external shunt control and adds capacitors across the module SP input and output, the effect can be quite dramatic. BEFOREAFTER 1.0fC 0.5fC 0.75fC Double Trigger Noise now clean at 0.75fC (apart from the known bad chip) * 22uF 2 Data from P.W. Phillips (RAL) 100nF

Serial Powering with a Stavelet Module: Recent Results Good results also obtained when using a completely Standalone shunt circuit (ABCN-25 shunts disabled) together with capacitors across the module. ENC still good Clean Double Trigger Noise at 0.75fC Minimal noise bands at 0.50fC Reducing the impedance of key connections has also helped here (note copper tape) fC H0 H e 611e 609e 588e Data from A. Greenall (Liverpool)

Serial Powering with a Stavelet Module: Recent Results Another option studied involves setting both hybrids of a stavelet module at the same DC potential, known as the “chain of modules” configuration. Whilst for ABCN-25 this requires a loop current of 10A, with 130nm technology the current would be much lower, making this a viable option. “Chain of 0.5fC“C of M” with 0.5fC“Chain of 0.5fC Data from A. Greenall (Liverpool)

Serially Powered Stavelet AS BUILT Serial “Chain of Hybrids” – Bypass any hybrid under DCS control (one wire) Good ENC noise – Slightly higher than single module results - especially for first and last hybrids in the chain - but acceptable Very Poor Double Trigger Noise performance – Bands visible already at 1.0fC Might some of the modifications tested with single modules help? Custom Current Source Prague AS / STFC RAL 5

Modification of Stavelet Module M0 Front View Rear View 1.Make hybrid at lowest potential DC coupled (originally true only for M0) 2.Make low inductance DC connection between shield pad under sensor and GND of lowest hybrid (becomes reference point for the module) 3.Use external shunt control 4.Reduce DC impedance between hybrids (101 strand wire) 5.Reduce AC impedance across module (capacitors & copper tape) BEFOREAFTER 1.0fC 0.5fC 0.75fC Double Trigger Noise now clean at 0.75fC! 6 Data from P.W. Phillips (RAL)

1.Flip AC/DC bonding 2.Use external control of distributed shunts 3.Add low Z shield connection 4.Bridge SP across hybrids using copper tape and caps 5.Route SP between hybrids through 101 strand wire NOT through the bus tape In fact point 5 seems to be the most critical. Placing caps across each hybrid works pretty much as well as caps placed across the hybrid pair Modification of Stavelet Module M1 BEFOREAFTER 1.0fC 0.5fC 0.75fC Double Trigger Noise now clean at 0.75fC! 7 Data from P.W. Phillips (RAL)

AND NOW THE BAD NEWS: ENC for modifed modules M0 and M1 is rather poor  28 th July

DC-DC with a Stavelet Module: Early Results Slide originally presented by G. Blanchot (CERN), AUW, 30/03/2011 Data from A. Greenall & T. Affolder (Liverpool) 9

DC-DC with a Stavelet Module: Recent Results An assembly was made placing STV10 DC-DC converters adjacent to the module, similar to the geometry of a stavelet. Initial results were poor. Improved by: Improving sensor shield connection Moving from “bus” to “star” topology Adding a second backplane connection Now within ~20ENC of SP reference data! Proves screening cans are adequate Problems due to system hookup issues SP Reference DC-DC “bus” topology DC-DC “star” topology H0 H1 10 Data from A. Greenall (Liverpool)

DC-DC Stavelet TTi TSX3510P Commercial PSU AS BUILT Common bus feeds STV10 DC-DC converters from CERN group – Enable / disable any converter under DCS control (one wire) Good Double Trigger Noise performance – Bands only at 0.5fC Poor ENC noise performance – OK running one hybrid at a time, but H0 very noisy when run both Might some of the modifications tested with single modules help? 11

“STAR” Topology: A short twisted pair runs from each converter to a common point on the bus Separate Power Feeds: H0 twisted pair H1 from the bus “BUS” Topology: Both converters bonded to a common power bus, with 6cm between connections SP Reference Data before module glued to stavelet (Liverpool) DC-DC stavelet: best result requires seperate power feeds (avoid common impedance coupling) 12

Stavelet Outlook DC-DC Identify other possible routes for conducted noise between the two converters, and eliminate them – Connect sensor shield to STAR point? Implement second backplane connection – Might this bring “seperate feeds” performance of H0 into line with expectation? Once happy with M0 performance, add another module – Will this introduce further noise problems? Proceed with caution! Serial Powering Improve ENC performance of modified modules – 10uF between high side 0V and shield? Modify one module to “chain of modules” – Does this work better? High priority to get a serially powered stavelet to CERN – Choose optimum configuration, implement, and ship ASAP. – Studies will then continue in B180 Will then build a new SP stavelet – Modified PPB boards? Lower Z between hybrids – Revised bus tape layout? Lower Z shield connection 13

BACKUP SLIDES

Jan Stastny Current Source at 5A, 230V bias, ALL MODULES ON 8 th July 2011 Serially Powered Stavelet: ENC NOISE 15

Double Trigger Noise: Basic Metric : Columns 0-3 at 0.75fC1730-8: Columns 0-3 at 0.50fC Sum(hits): simply sum the number of hits shown in each double trigger plot DC-DC Stavelet: Double Trigger Noise 12 th July

Naked Converters! Converter 06: BC AConverter 14: 7C D23A DC-DC Stavelet 17