CNGS Prot on beam line: news since NBI 2002 OUTLI NE 1. Overview - PowerPoint PPT Presentation

CNGS Prot on beam line: news since NBI 2002 OUTLI NE 1. Overview 2. Beam optics 3. Trajectory correction scheme 4. Beam stability 5. Aperture checks 6. Need of a collimator 7. Summary NBI 2003 7-11 November 2003 1 Present at ion by Malika Meddahi.

Overview NBI 2003 7-11 November 2003 2 Present at ion by Malika Meddahi.

Nominal beam paramet ers Beam parameters Nominal CNGS beam Nominal energy [GeV] 400 Normalized emittance [ µ m] H=12 V=7 Emittance [ µ m] H=0. 028 V= 0. 016 Momentum spread ∆ p/ p 0. 07 % +/ - 20% # extractions per cycle 2 separated by 50 ms # of train per extraction 1 Upgrade # of bunches per train 2100 phase: I ntensity per extraction [10 13 p] 2. 4 3.5 10 13 p Bunch length [ns] (4 σ ) 2 r. m. s. bunch length [cm] 15 Bunch spacing [ns] 5 Train length [ µ s] 10. 5 NBI 2003 7-11 November 2003 3 Present at ion by Malika Meddahi.

Opt ics at Target (1) Nominal paramet ers : • Bet a at f ocus in bot h planes : 10 m • σ x , σ y at 400 GeV [mm]: 0.53 / 0.4 • σ ’ x , σ ’ y at 400 GeV [mrad]: 0.05 / 0.4 NBI 2003 7-11 November 2003 4 Present at ion by Malika Meddahi.

Opt ics at Target (2) β x [m] 2.5 10 20 30 • Round beams σ x [mm] 0.26 0.53 0.75 0.91 • I ncr ease σ β y [m] 2.5 10 20 30 σ y [mm] 0.2 0.4 0.56 0.7 Going to 30 m: feasible but reaching the power supply limit and aperture limit (swapped power supplies) NBI 2003 7-11 November 2003 5 Present at ion by Malika Meddahi.

Traj ect ory correct ion scheme (1) AI M : • I s t he proposed scheme suf f icient ? • Can we save some correct ors or monit ors? • What happens if somet hing goes wrong (w.r.t . f ault y correct ors or monit ors) Took int o account : Beam line errors (quad displacement , beam posit ion monit or, dipole f ield and t ilt , ext ract ion f rom SPS) NBI 2003 7-11 November 2003 6 Present at ion by Malika Meddahi.

Traj ect ory correct ion scheme (2) 2-in-3 scheme: 2 consecut ive half cells per plane out of 3 are equipped wit h Beam Posit ion Monit ors (BPMs) and correct ors. Phase advance per cell: π / 2 Produce π bumps which may not be visible as t he t raj ect ory is heavily under-sampled. Problem worsen when some BPMs are malf unct ioning � Reading of t he posit ions in bot h planes (X, Y) f or all BPMs � Add one BPM NBI 2003 7-11 November 2003 7 Present at ion by Malika Meddahi.

Traj ect ory correct ion scheme (3) Correct or st rengt h and ef f iciency scrut inized 3000 t raj ect ory correct ions Max. St rengt h f or t he new dipole correct ors: 60 µ rad Two correct ors were removed f rom t he scheme Use some bending magnet s as addit ional correct ors. NBI 2003 7-11 November 2003 8 Present at ion by Malika Meddahi.

Traj ect ory correct ion scheme (4) Traj ect ory max. RMS max (mm) X bef ore t raj ect ory. Correct ion 3.57 (3.58) 10.98 (15.02) X af t er t raj ect ory correct ion 0.65 (0.65) 2.02 (2.68) Y bef ore t raj ect ory. Correct ion 3.24 (3.20) 7.50 (8.02) Y af t er t raj ect ory correct ion 0.49 (0.62) 1.42 (2.52) Reminder: max. t raj ect ory excursion allowed: 4.3 mm The proposed correct ion scheme is suf f icient NBI 2003 7-11 November 2003 9 Present at ion by Malika Meddahi.

Apert ure checks (1) AI M : I nvest igat e t he apert ure of t he prot on beam line Met hod: - Generat e 100 000 part icles according t o Gaussian dist ribut ion t o f ollow t he cont our of t he emit t ance ellipse - Populat e t ails of dist ribut ion NBI 2003 7-11 November 2003 10 Present at ion by Malika Meddahi.

Apert ure checks (2) Horizont al phase space mrad mrad St art of t he line At t arget 10 σ 10 σ 6 σ 6 σ mm mm NBI 2003 7-11 November 2003 11 Present at ion by Malika Meddahi.

Apert ure checks (3) Vert ical phase space mrad mrad St art of t he line At t arget 10 σ 10 σ 6 σ 6 σ mm mm NBI 2003 7-11 November 2003 12 Present at ion by Malika Meddahi.

Apert ure checks (4) Fract ion of part icles lost f or dif f erent apert ure misalignment s and moment um of f set s. 100000 part icles t racked For nominal paramet ers, no part icle losses are observed. Losses occur f or larger apert ure misalignment s or larger moment um of f set s NBI 2003 7-11 November 2003 13 Present at ion by Malika Meddahi.

Beam st abilit y at t he t arget (1) AI M : I nvest igat e t he beam spot st abilit y at t he t arget � Target resist ance t o non-cent ered beam Took int o account : Beam line imperf ect ions (quad displacement , beam posit ion monit or, main dipole f ield and t ilt , ext ract ion, power supply precision) NBI 2003 7-11 November 2003 14 Present at ion by Malika Meddahi.

Horizont al σ x Horizont al σ ’ x Type of error Error magnit ude at t arget at t arget ( µ rad) (mm) 11 µ rad Magnet errors As def ined 0.12 mm 10 µ rad r.m.s. 5 µ rad Horizont al ext ract ion angle 0.11mm 21 µ rad Horizont al ext ract ion posit ion 0.5 mm r.m.s. 0.32 mm 21 µ rad Ext ract ion angle and posit ion As above 0.34 mm 22 µ rad Magnet and ext ract ion errors As above 0.36 mm 53 µ rad Nominal beam size [r.m.s.] 0.53 mm 57 µ rad Ef f ect ive beam size [r.m.s.] 0.64 mm NBI 2003 7-11 November 2003 15 Present at ion by Malika Meddahi.

Beam st abilit y at t he t arget (3) Horizont al plane spot size is dominat ed by ext ract ion errors Vert ical beam spot size is not increased, vert ical beam posit ion is det ermined by t raj ect ory errors. NBI 2003 7-11 November 2003 16 Present at ion by Malika Meddahi.

Overall beam st abilit y at t he t arget (4) I nj ect ion and magnet errors 0.36 mm (horizont al σ at t arget ) Tot al BPM rms incert aint y 0.32 mm (?) Target overall precision 0.30 mm (?) Tot al: ~0.60 mm For β =10 m, nominal σ beam = 0.53 mm On t arget f irst 2 rods (5 mm diamet er) : 2.5 mm – (3 σ beam + 0.6mm) = 0.31 mm On t arget f ollowing rods (4 mm diamet er) : 2.0 mm – (3 σ beam + 0.6mm) = -0.19mm NBI 2003 7-11 November 2003 17 Present at ion by Malika Meddahi.

Need of a collimat or (1) NBI 2003 7-11 November 2003 18 Present at ion by Malika Meddahi.

9mm 7mm 7 5.5 5 3.5 4.5 3.2 6 σ +/- 6 σ +/- 10.3m 3.2 3.5 4.5 5.5 5 7 7mm 14 mm diameter 9mm Collimator Horn neck NBI 2003 7-11 November 2003 19 Present at ion by Malika Meddahi.

Summary Beam dynamics st udies conf irmed earlier preliminary st udies. Result s on t raj ect ory correct ions, apert ures st udies, beam st abilit ies, need of a collimat or t o prot ect t he horn neck. Prot on beam line “on schedule” General services: Oct ober 2004 t o J uly 2005 Equipment : August 2005 t o J anuary 2006 Cold check-out : Feb-March 2006 Test wit h beam: April 2006 NBI 2003 7-11 November 2003 20 Present at ion by Malika Meddahi.