CNGS Prot on Beam Line I nst rument at ion OUTLI NE 1. BPM System Update - Requirement s - Acquisit ion syst em 2. BCT System Update - Requirement s - Acquisit ion syst em For other systems see NBI 2002 talk by R. Jung 1 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Posit ion Monit oring CNGS Beam Position Measurement Requirements I n t e n s i t y R a n g e : 1 × 1 0 2 t o 3 . 5 × 1 0 1 1 3 Original 18 But t on Elect rode BPMs in TT41 60mm Apert ure 340 4 St ripline Couplers in TT40 BEAM will see bot h LHC & CNGS beams 110 110 short circuits BPCKD (double) Modif ied 2 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Posit ion Monit oring CNGS Beam Position Measurement Acquisition System BP BP BP LP LP LP Filt er Filt er Filt er Filt er Filt er Filt er I t o V I t o V Logamp Logamp Conver t er Conver t er A A Dif f . Dif f . Ampli Ampli BP BP BP B B LP LP LP Filt er Filt er Filt er Posit ion = K * V out Posit ion = K * V out I t o V I t o V Filt er Filt er Filt er Logamp Logamp Convert er Convert er • Each signal is compressed by a logarithmic amplif ier, f iltered and applied to a dif f erential amplif ier. • The position response is: Pos ≡ [log(A/ B)] = [log(A)- log(B)] ≡ (V out ) where V out is the voltage dif f erence between the log- amp outputs 3 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Posit ion Monit oring CNGS Beam Position Measurement Acquisition System Logarithmic Amplif iers 200MHz BP f ilters Log 200MHz Att Amp 2 in parallel per elect rode Up 3 Way Log Directional 200MHz Splitter Amp Coupler t o improve linearit y V Up - Down Integrator Pickup Right Log Directional Att 200MHz (BPK/BPG) Amp Coupler Down 3 Way Analog Multiplexer Log Directional 200MHz Splitter Amp Coupler S U + D + L + R Left Manchester Integrator ADC Directional encoder Coupler Log Att 200MHz Amp 1 cable t ransmit s: 3 Way Log 200MHz • H posit ion Splitter Amp H Left - Right Integrator • V posit ion Log Att 200MHz Amp • I nt ensit y 3 Way Log 200MHz Splitter Amp Auto Trigger Sequencer Calibrator Logic 4 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Posit ion Monit oring CNGS Beam Position Measurement Acquisition System Why t his choice? ⇒ low cost – as it requires only 1 coax cable per pick-up. ⇒ large dynamic range wit hout requiring gain swit ching. ⇒ simple engineering ⇒ aut ot rigger capabilit y Pot ent ial Problems: ⇒ linearity with position o log amp has inherent non-linearit y in t he % of apert ure range o hopef ully improved using a compensat ion log amp in parallel ⇒ radiation issues with digital electronics in the tunnel o Experience gained f rom t est ing LHC component s o At t empt t o use radiat ion t olerant component s 5 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Current Monit oring CNGS Beam Current Monitoring Requirements T w o M o n i t o r s – o n e a t t h e b e g i n n i n g & o n e a t t h e e n d o f t h e l i n e A b s o l u t e A c c u r a c y o f 1 % f o r t h e I n t e n s i t y R a n g e : 1 × 1 0 2 t o 3 . 5 × 1 0 1 1 3 First BCT sees both LHC & CNGS beams • Has t o f ulf ill addit ional requirement of LHC bunch by bunch capabilit y (i.e. 25ns resolut ion) New development f or LHC - Fast BCT (BFCT) • 500MHz Bandwidt h → Not required f or CNGS Low droop (~0.1%/ µ s) • → 1% ef f ect f or CNGS 6 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Current Monit oring CNGS Beam Current Measurement Acquisition System Analogue Acquisit ion based on a f ast Integrator Output Integrator Output int egrat or chip → Designed by t he Laborat oire de Physique Corpusculaire, Clermont - Ferrand f or use in t he LHCb Preshower Det ect or. (Large Hadr on Collider beaut y 25ns 25ns experiment f or precise measurement s of CP violat ion and rare decays) → Uses int erleaved, 20MHz int egrat ors and sample & hold circuit ry t o give BFCT Signal after 200m of Cable BFCT Signal after 200m of Cable 40MHz dat a (only t ot al sum required f or CNGS) 7 NBI2003 - Rh. Jones (CERN - AB/BDI)
CNGS Beam Current Monit oring CNGS Beam Current Measurement Calibration Fast BCT f itted with calibration winding. Switched current source injects 128mA f or 5 µ s equivalent t o 2 × 10 10 charges in 25ns o same signal level as a CNGS t rain of 8.4 × 10 12 prot ons o 460 DCCT_SPS 440 Intensity (x10^10) 420 Comparison bet ween DCCT and BFCT_SPS 400 BFCT in t he SPS 380 Shaded region represent ± 2% 360 340 320 300 0 1000 2000 3000 4000 5000 6000 Time in Cycle (ms) 8 NBI2003 - Rh. Jones (CERN - AB/BDI)
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