Advanced Photon Source. RF Beam Position Monitor Upgrade Robert M. Lill

Transcription

1 Advanced Photon Source RF Beam Position Monitor Upgrade Robert M. Lill

2 Filter Comparator (original design) to ATT LPF A+B ATT BPF S bo ATT ATT LPF 180 A-B 180 ATT BPF D x ti ATT LPF C+D ATT BPF D y to ATT LPF C-D DIV Test /Timing

3 Monopulse Receiver Dy Te st Dx Switch 90 deg LIM S+ j D Te st Hybrid X LP F A D/S S 0/1 80 LIM j S+D Te st LOG A S Control

4 Signal Conditioning and Digitizing Unit Sele ct D/S A Gated Integ. D/S A/D S A Peak Det. Gate Convert S A/D Latch To FIFO Memory Convert Gate Buttons Trig. Rec. Mode TIMING ARM To Rec.

5 RFBPM Upgrade Design Objectives Reduce Insertion Loss of Receiver Front- End Reduce Reflected Power Between Receiver and Buttons Electrodes Reduce Time domain Band-Pass Filter Side Lobes Improve System Maintainability

6 Filter-Comparator Upgrade to Z/LP BPF A+B S bo Z/LP BPF 180 A-B 180 Dx ti Z/LP BPF 180 C+D 180 D y to Z/LP BPF C-D TEST COUPLER PHASE ADJUST

7 Phase I Matching Network Matches the output of the button electrode to 50 ohms and eliminates the need to place 6 db attenuators on the output of the button electrodes. Facilitates moving the band pass filter and comparator out of the tunnel. Band limits (100 MHz) the output of the button electrodes. Increases button output by 8 db

8 Matching Network Development ESRF narrow band (8 MHz 3 db BW) 16.5 db signal improvement PTI (50 MHz 3 db BW) with 15 db signal improvement Angle Linear broad band (100 MHz 3 db BW) with 8 db improvement includes LPF

9 ESRF Matching Network 8 MHz BW I beam 5pf 2 pf 37 nf

10 Matching Network 50 MHz BW 1 I beam 5pf 2 pf 30 nf

11 Matching Network 100 MHz BW with lowpass filter nf 13 nf I beam 5pf 20 pf 10 pf

12 100 MHz BW matching network with lowpass filter as built

13 Button Electrode Matching Network Implementation

14 Capacitive Button Electrodes Button electrode reflects 97 % power on feed through side Requires attenuators close to output to minimize reflections

15 Capacitive Button Electrodes with Matching Network Button/matching network measure greater than 30 db return loss 13 dbm (20 mw) button output power in a 100 MHz bandwidth

16 Matching network output with ma/bunch

17 Phase II Upgrade Bandpass Filter and Monopulse Comparator Increases signal strength by removing matching attenuators and by using low loss components Improves return loss Improves bandpass time domain side lobe rejection

18 Bandpass Filter Development Coaxial cavity resonator Transversal coaxial delay line Transversal stripline serpentine design Transversal surface acoustic wave (SAW)

19 Transversal Bandpass Filter t1+trf*3 t1+trf*2 t1+trf*1 Delay t1 8 way splitter 8 way splitter t1+trf*4 t1+trf*5 t1+trf*6 t1+trf*7

20 Surface Acoustic Wave (SAW) Bandpass Filter

21 Cavity filters with ma/bunch sum input

22 16 pulse transversal filters with 6 bunches

23 Receiver output with Cavity bandpass with ma/bunch

24 Receiver output with Lorch bandpass filter

25 Lorch bandpass filter response

26 Receiver output with 16 MHz Cavity bandpass filter

27 Receiver output with16 pulse transversal bandpass filter

28 Monopulse Comparator Specification

29 Maintainability Test couplers provide access to input signals during operation Test couplers provide injection points for self test Access to the tunnel to calibrate and repair are minimized Future improvements to add sector calibration module can be realized

30 Major Design Differences Matches the button impedance vs. attenuating reflected standing waves Moves comparator and band pass filter out of the accelerator tunnel Different comparator and band pass filter topologies

31 R&D PLAN Obtain 4 SAW filter prototypes as soon as possible Obtain 4 serpentine transversal filter laid out on low cost substrate as soon as possible Obtain 9 component rat race hybrid networks (connectorized) by CY98 Obtain 36 bandpass filters of choice (connectorized) by CY98

32 Cost Phase I cost $150,000 Phase II comparator estimated cost $250,000