240 likes | 329 Views
Decay Ring Study. m. apollonio. 22/04/2009 UKNF09 - Lancaster. MADX calculations - Twiss: working points, chromaticity - chromaticity corrections (sextupoles) tracking and determination of DA Few words on Decay Losses.
E N D
Decay Ring Study m. apollonio 22/04/2009 UKNF09 - Lancaster
MADX calculations- Twiss: working points, chromaticity- chromaticity corrections (sextupoles) • tracking and determination of DA • Few words on Decay Losses 22/04/2009 UKNF09 - Lancaster
Lattice: race track scheme 1- original design from C. Prior 2- MADX format by J. Pasternak 22/04/2009 UKNF09 - Lancaster
match straight 1x 1x 12x 1x 1x 7x 7x cell arc 22/04/2009 UKNF09 - Lancaster
Pm = 25 GeV/c L=1608 m 22/04/2009 UKNF09 - Lancaster
Working Point / Chromaticity • Qx = 8.5229 DQx=-11.2149 • Qy = 8.2127 DQy= -9.9437 Dp/p 22/04/2009 UKNF09 - Lancaster
Chromaticity Correction: sextupoles in the arcs 0.5 m 0.4 m 2m 0.5 m 0.7 m 0.7 m Dp/p 22/04/2009 UKNF09 - Lancaster
idea: correcting for nat. chromaticity and avoid dangerous resonances introduces non-linearity reducing DA (see later) Dp/p 22/04/2009 UKNF09 - Lancaster Dp/p 22/04/2009 UKNF09 - Lancaster
Close Up plot for the Working Point 22/04/2009 UKNF09 - Lancaster 22/04/2009 UKNF09 - Lancaster
Dynamic Aperture: MADX+makethin • Tracking muons for 500 turns from P0: • Monitor after N passes [P0,P1,P2,…] • MAX aperture of the ring, Rmax=1m • If Rm > Rmax particle lost • Initial parameters: x=[xm,XM], x’=0, y=y0,y’=0 P1 P0 22/04/2009 UKNF09 - Lancaster
Poincare’ plot (x,x’) with increasing initial X 20000 turns Position – 0
20000 turns Position – 3
Y An example of tracking in a RING with no sextupoles scan x fix y0 X X’ Y’ 500 m transmitted X Y
Y An example of tracking in a RING with correcting sextupoles scan x fix y0 X X’ Y’ 500 m transmitted Y X
baseline acceptance eN=30 mm rad e = eN * mm/P0 bx= 14 m by= 5 m sX= 40 mm sY= 25 mm no-sext: P=27 GeV/c no-sext: P=24 GeV/c no-sext: P=25 GeV/c no-sext: P=26 GeV/c sext-correct: P=26 GeV/c sext-correct: P=25 GeV/c sext-correct: P=24 GeV/c 9x eN 22/04/2009 UKNF09 - Lancaster
ANY (mm rad) no-sext: P=25 GeV/c sext-correct: P=25 GeV/c 30 mm rad acceptance ANX (mm rad) 22/04/2009 UKNF09 - Lancaster
G4Beamline reproduction of the Decay Ring muons let decay electrons straight section matching section arc Dipole virtual detector planes QD QF 22/04/2009 UKNF09 - Lancaster
Conclusions … • initial study on the optics for DKrings (racetrack) with • MADX(working point, opt. functions, dispersion…), • introduction of sextupolesin the arcs to compensate for • natural chromaticity, • resonance diagram, • Dynamic Apertureinvestigated (with and w.o. sextupoles). • … and future work • - continuation od Decay Loss studies via G4Beamline • Initial Study with PTC(not shown here) need to be • consolidated (tracking in thick elements), • MisalignmentandField Errorsto be introduced: see • how DA is degraded, • IntroduceRFcavities 22/04/2009 UKNF09 - Lancaster
2ns 3ns Flux Determination • 1021m/yr (1yr = 200 days) = 5.8x1013m/s • 50 Hz (proton) rep. rate • 1.15x1012m/(train-triplet) 3.8x1011m/train • 3 bunch trains, 440 ns long (88 bunches of 2 ns each) • 3.8x1011m/T(440ns)= 140 mA • 4.4x109 m/B(2ns) = 350 mA • tm=2.2*(E/m) msec = 520 msec 88 B (T) (S) 440ns 1200ns 1640ns (TS) tm=520 msec 2x104msec = 50Hz rep.rate
How to ? Current Transformers with a) Ib=150 mA / 350 mA b) integration time 440ns / 2 ns c) good frequency response (200 MHz) [do we want/need to measure the single bunch?] NB: F(t) ~ e-t/tm , so after 3.7 msec we have 100 mA / train (minimum detectable current?) - which precision do we need? - when do we stop being sensitive? Can we use complementary methods? e.g. counting electron flux from m decays in the straights?
Possible NF-LAYOUT at RAL? IDS meeting - CERN 24