Target/Beam Interaction M. Apollonio, A. Dobbs - IC 27/11/20081MICE Target Workshop - IC

Motivations: optimise secondary production minimising dangerous losses in ISIS assess better orientation/shape of the shaft for secondary production a work at “four hands”: A. Dobbs, ORBIT simulation of ISIS ring / interaction with target / comparison with data taken from MICE shifts, MA, G4Beamline simulation of secondary production with a set of shafts 27/11/20082MICE Target Workshop - IC

ORBIT Results 27/11/20083MICE Target Workshop - IC A. Dobbs

25/11/08ORBIT Results, Adam Dobbs4 - overview of results obtained from simulating beam loss in ISIS synchrotron - using code ORBIT - emphasis to loss caused by MICE target - results for 3 target orientations: long-thin short-fat tilted or parallel to the MICE beamline - 2 target sizes are used: 10mm x 1mm and 1mm x 1mm - dip depths ranging from 27mm to 24mm above beam axis are shown. 27/11/20084MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs5 Target Orientations (variable depths) “Short-Fat” – 1mm along z – axis, 10mm along x - axis “Long-Thin” – 10mm along z – axis, 1mm along x – axis (true orientation) “Reduced” – 1mm along z – axis, 1mm along x - axis 27/11/20085MICE Target Workshop - IC x y s

25/11/08ORBIT Results, Adam Dobbs6 Model The MICE target is modelled as a block of iron inserted into the ISIS beam 2ms before extraction, sitting at a position of ~115m around the synchrotron ring. The target is also currently modelled as being static. Work is being done about the possibility of improving the model to make the target titanium and dynamic. 27/11/20086MICE Target Workshop - IC NB: ORBIT phys.models elastic/inelastic/nuclear

27/11/2008MICE Target Workshop - IC7 TGT

25/11/08ORBIT Results, Adam Dobbs8 Results 2D histograms showing number of particles lost from the beam as a function of time in an ISIS spill and the position in the synchrotron in which they were lost. Further a table is also presented for each target configuration, showing the number of “hits” (intersections of the volume) in the MICE target, for the last 2ms of the ISIS spill The tables also give the number of particles “absorbed” by the target i.e. turned into lost particles by their interaction with the target. 27/11/20088MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs9 Injection losses MICE target losses Short-Fat: 27mm above axis, -1 to 10ms 27/11/20089MICE Target Workshop - IC zoom last 2 ms

25/11/08ORBIT Results, Adam Dobbs10 Short-Fat: 27mm above axis, 8 to 10ms 27/11/200810MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs11 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200811MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs12 Long-Thin: 27mm above axis, -1 to 10ms (NB: present config) 27/11/200812MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs13 Long-Thin: 27mm above axis, 8 to 10ms 27/11/200813MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs14 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200814MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs15 Long-Thin: 26mm above axis, -1 to 10ms 27/11/200815MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs16 Long-Thin: 26mm above axis, 8 to 10ms 27/11/200816MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs17 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200817MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs18 Long-Thin: 27mm above axis, 25 0 rotation, -1 to 10ms 27/11/200818MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs19 Long-Thin: 27mm above axis, 25 0 rotation, 8 to 10ms NB At present there remains an ambiguity in the direction of the rotation, clockwise or anti-clockwise. If / when this is resolved it will be published in an updated version of this document. 27/11/200819MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs20 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200820MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs21 Reduced: 27mm above axis, -1 to 10ms 27/11/200821MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs22 Reduced (1mm^2): 27mm above axis, 8 to 10ms 27/11/200822MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs23 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200823MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs24 Reduced: 26mm above axis, 8 to 10ms 27/11/200824MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs25 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200825MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs26 Reduced: 25mm above axis, 8 to 10ms 27/11/200826MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs27 NameIndexPosition [m]# Hits# AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200827MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs28 Reduced: 24mm above axis, 8 to 10ms 27/11/200828MICE Target Workshop - IC

25/11/08ORBIT Results, Adam Dobbs29 NameIndexPosition [m]# Hits#AbsorbedEfficiency Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200829MICE Target Workshop - IC

Circular-solid 6mm radius: 27mm above axis, 8 to 10ms 27/11/200830MICE Target Workshop - IC

NameIndex Position [m] # Hits # Absorbe d Efficie ncy Mice Mice Mice Mice Mice Mice Mice Mice Mice Mice /11/200831MICE Target Workshop - IC

27/11/2008MICE Target Workshop - IC32 SUMMARY of the SUMMARIES ORBIT Results Summary TargetRunDepth above axis (mm)LP end of spillMICE Collimator HitsMICE Collimator Absorber% Efficiency Short Fat Long Thin Reduced Rotated 25deg Circular 6mm rad Long Thin Reduced Reduced Reduced in a sh.fat config. losses happen far from the tgt point -the long-thin (or cylindrical) config. suggest most of losses happen in S7-8, closer to the TGT prod point - more controllable with collimators/scrapers?

G4Beamline Studies 27/11/200833MICE Target Workshop - IC M. Apollonio

27/11/200834MICE Target Workshop - IC - is there a better shape for the target or orientation? - how many secondaries (pi) do we get at the Q1 bore (per impinging proton?) - what about materials? ISIS p trajectory Q o MICE TGT

10 mm X Z 25 deg Q1-TGT axis 25 deg lost to Q1 secondaries production 20<theta<30 propagation to plane A acos(Pz/Ptot)>20 && acos(Pz/Ptot)<30 rotation & propagation to plane B A A B C shift & align with Q1-TGT axis LONG SLIM 35

25 deg FAT SHORT TILTED TGT 10 o / 25 o 27/11/200836MICE Target Workshop - IC

25 deg Cylinder: OD=6mm/ID=4.7 mm Materials: Ti Be Al 27/11/200837MICE Target Workshop - IC

Tgt_long_slim_rot0: y:x Nprimaries=100M 27/11/200838MICE Target Workshop - IC A

Tgt_long_slim: y:x rotation 25 deg + shift /11/200839MICE Target Workshop - IC B

27/11/200840MICE Target Workshop - IC at Q1 plane in Q1 bore C

Tgt_tilt25_rot0: y:x Nprimaries=100M 27/11/200841MICE Target Workshop - IC A

At Q1 plane Q1 bore 27/11/200842MICE Target Workshop - IC C

Tgt_short_fat_rot0: y:x 27/11/200843MICE Target Workshop - IC

Tgt_cyl_rot0: y:x 27/11/200844MICE Target Workshop - IC

27/11/200845MICE Target Workshop - IC

27/11/200846MICE Target Workshop - IC

27/11/2008MICE Target Workshop - IC

27/11/200848MICE Target Workshop - IC CONCLUSIONS - neither the shape nor the orientation of a target seem to alter significantly the production of secondaries to Q1 - the overall material volume intercepted by the beam is the main parameter (reasonable) - material other than Ti (lower A/rho) generate less secondaries (in particular pions) -a good balance should be found between weight / mechanical stiffness / and pion production -a hollow cylinder is a good solution, certainly does not worsen the performances of the present configuration