Overview of Resultsfrom Electrical Stavelets

Peter W Phillips et al13/07/2011

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Serially Powered Stavelet

DC-DC Stavelet

H0 H1 H2 H3 H4 H5 H6 H7 EoS

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Jan Stastny Current Source at 5A, 230V bias, ALL MODULES ON

8th July 2011Serially Powered Stavelet

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Double Trigger Noise: Basic Metric

1722-7: Columns 0-3 at 0.75fC 1722-8: Columns 0-3 at 0.50fC

Sum(hits): simply sum the number of hits shown in each double trigger plot

220052

262759

0

0

599661

630266

88

78

Serially Powered Stavelet 8th July 2011

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Double Trigger Noise: Basic Metric

0 2 4 6 8 10 12 14 160

200000

400000

600000

800000

1000000

1200000

1.00fC0.75fC0.50fC

SP- SP+

Sum(hits)

Hybrid

L1A over COM, no additional delay (run 1580)

Serially Powered Stavelet 20th May 2011

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Serially Powered Stavelet

SP Stavelet Summary Good ENC noise performance Can bypass individual hybrids under DCS control (PPB / 1-wire) Excess noise occupancy correlated with readout, notably “even” hybrids

Have explored lots of ideas with single SP modules and/or the stavelet• Extra decoupling (helps a bit)• Improved referencing• Second backplane connection• Alternate shunt control circuits

– M shunt plugin, SPP-COB chip

Studies with a single module show that the double trigger noise is reduced if both hybrids on a detector sit at the same DC potential (see Tony’s talk)

• Proposal is to convert stavelet from a “chain of hybrids” to a “chain of modules” – Maybe just build a new one?

• Likely to give us a Serially Powered stavelet which meets required noise targets– Not as efficient as a “chain of hybrids”, should continue to work toward that in parallel

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DC-DC Stavelet

Single Module Reference Result

12th July 2011Stavelet + 47uF:

One hybrid at a time

12th July 2011Stavelet + 47uF:

Both hybrids at once

Double Trigger Noise: Basic Metric

1730-7: Columns 0-3 at 0.75fC 1730-8: Columns 0-3 at 0.50fC

Sum(hits): simply sum the number of hits shown in each double trigger plot

15

4

0

0

2898

2442

9

85

DC-DC Stavelet 12th July 2011

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DC-DC Stavelet Summary Better Double Trigger Noise performance Can disable/re-enable hybrids under DCS control (1-wire) Performance of H0 not yet satisfactory

• Contrary to an earlier successful test of a stavelet module powered by STV DC-DC converters, initial results on the stavelet were not encouraging– Explored B field mapping and extra shielding

• Minimal effect– Explored improved ground referencing

• Minimal effect (but maybe did not go far enough)– Explored frequency spectrum of noise on the DC-DC power bus

• Artefacts from converters and peaks from other sources such as HSIO

• Latest result achieved by the addition of capacitors to the power bus

• Still investigating ways to recover the performance of H0

DC-DC Stavelet

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BACKUP

Probing the power bus: up to 2MHz

These measurements were made using an 800 MHz bandwidth diff probelocated at the position where “H3” would normally be connected

Power ONH0 + H1 + H2 active

Power ONH0 + H1 + H2 active

47uF held at location H4

DC-DC Stavelet

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Naked Converters!Converter 06: BC0000000476043A Converter 14: 7C0000000455D23A

DC-DC Stavelet

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