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Rod Power Line Low-Pass Filter Study. 3 August 2004 Sam Burke UCSB HEP Group. Progress. Noise on CERN Rod Test System Power line is source per battery tests 2.5 mV @ 1Mhz measured on Rod PS @UCSB Low Noise on UCSB Rod System 1 - 2 A/D Counts. Progress. Inject Noise into UCSB system
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Rod Power Line Low-Pass Filter Study 3 August 2004 Sam Burke UCSB HEP Group CMS Tracker Rod Filters Sam Burke EE
Progress • Noise on CERN Rod Test System • Power line is source per battery tests • 2.5 mV @ 1Mhz measured on Rod PS @UCSB • Low Noise on UCSB Rod System • 1 - 2 A/D Counts CMS Tracker Rod Filters Sam Burke EE
Progress • Inject Noise into UCSB system • introduce noise pulse train into 0.1 ohm resistor placed at common power supply point and observe system response. Frequency near Tracker Shaper Band. • Reduce self-induced noise with filtering • Place Low Pass Filter on power line • Shaper Noise Band Defined • 1/260ns =4Mhz to 1/40ns =25Mhz • >60dB attenuation in shaper band CMS Tracker Rod Filters Sam Burke EE
Low Pass Filter Schematic CMS Tracker Rod Filters Sam Burke EE
LP Filter Response CMS Tracker Rod Filters Sam Burke EE
LP Filter Test Results CMS Tracker Rod Filters Sam Burke EE
LP Filter • Break 2 power lines and common line and insert filter. CMS Tracker Rod Filters Sam Burke EE
Open Filter Issues • Voltage drop • Vgnd=IR=19A*4.9mohms=93mV on Gnd • V+2.5=IR=12A*4.9mohms=60mV on 2.5V line • Heat Generation • I^2R=19^2*.0049ohms=1.7 watts on Gnd coil • I^2R=12^2*.0049=0.7 watts on 2.5V line coil • I^2R=7^2*.0049=0.24 watts on 1.25V line coil • Core Saturation in Machines Magnetic Field • Open core may saturate in field • Investigate toriod candidate CMS Tracker Rod Filters Sam Burke EE
Alternate Filter Approach • Move filter outside of CMS magnetic enviornment • No saturation of filter inductors • Need to insert (splice) filter into Rod Power Cables • Reduce heat generation by filter I^2 heating • Use lower winding resistance with a reduced noise attenuation if acceptable CMS Tracker Rod Filters Sam Burke EE
Alternate Inductor Impact CMS Tracker Rod Filters Sam Burke EE
Rod LP Filter Prototype • High Current Inductors are on the two DC Power lines. • Twisted pairs are power sense lines and analog sensor lines CMS Tracker Rod Filters Sam Burke EE
LP Filter At Rod Pwr. Line CMS Tracker Rod Filters Sam Burke EE
Pulse Transformer CMS Tracker Rod Filters Sam Burke EE
Rod Module 1 • Top: Noise injection of 10 ns pulse, 30 mhz, 10vpk into power supply common. • Bottom: Low Pass Filter in Power Circuit CMS Tracker Rod Filters Sam Burke EE
Rod Module 3 (under CCU) • Top: Noise injection of 10 ns pulse, 30 mhz, 10vpk into power supply common. • Bottom: Low Pass Filter in Power Circuit CMS Tracker Rod Filters Sam Burke EE
Rod Module 6 • Top: Noise injection of 10 ns pulse, 30 mhz, 10vpk into power supply common. • Bottom: Low Pass Filter in Power Circuit • >40% reduction in noise • Normal UCSB background level is ~2.5 a/d counts CMS Tracker Rod Filters Sam Burke EE
Future Plans • Create CERN like noise pattern • adjust frequency of pulser • can we filter this out? • Study power supply sense-line filtering • Test filter on CERN Rods that are experiencing high noise. CMS Tracker Rod Filters Sam Burke EE