Difference between revisions of "SHMS MC Working Group"

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= Meetings =
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== Meetings ==
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*[[Minutes SHMS MC 8 | Minutes for Dec 1 2011 meeting]]
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*[[Minutes SHMS MC 1 | Minutes for Sept 19 2011 meeting]]
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*[[Minutes SHMS MC 7 | Minutes for Nov 15 2011 meeting]]
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*[[Minutes SHMS MC 6 | Minutes for Nov 2 2011 meeting]]
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*[[Minutes SHMS MC 5 | Minutes for Oct 18 2011 meeting]]
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*[[Minutes SHMS MC 3 | Minutes for Sept 19 2011 meeting]]
 
*[[Minutes SHMS MC 2 | Minutes for Sept 2 2011 meeting]]
 
*[[Minutes SHMS MC 2 | Minutes for Sept 2 2011 meeting]]
 
*[[Minutes SHMS MC 1 | Minutes for June 8 2011 meeting]]
 
*[[Minutes SHMS MC 1 | Minutes for June 8 2011 meeting]]
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[[Category:SHMSinfo]]
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==SHMS Characteristics==
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 +
===Drawings of magnets===
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*[[Drawings_of_SHMS_magnets | Drawings of SHMS magnets ]]
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=== Study of the SHMS resolution ===
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*[[Study of SHMS resolution | Study]] of the SHMS resolution.
  
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=SHMS Characteristics=
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== SNAKE ==
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Moved Snake section [[SNAKE Transport code | here.]]
  
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*Drawings of magnets:
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== COSY ==
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**[[https://hallcweb.jlab.org/wiki/images/d/d2/Shms_q3_dipole_sideview.jpg Side view drawing ]] of the SHMS Q3 and Dipole with distances. The far left cross hair in the drawing is the x_hut=y_hut=z_hut=0 point from which the detector positions are measured in the hut. The distance from the dipole center to the "zero" point projected perpendicular to the mechanical center axis of the dipole is 3.65m as shown on [https://hallcweb.jlab.org/wiki/images/d/d2/Q3-dipole.pdf an annotated] drawing with the calculation. [[https://hallcweb.jlab.org/wiki/images/5/51/Shms_detector_distances.jpg Plot]] of detector distances from the "zero" point. (From Mike Fowler on Sept 12th, 2011)
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[[https://hallcweb.jlab.org/wiki/images/f/f7/Gaskell_shms2009.pdf Dave G. notes on 2009 shms studies]]
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**[[https://hallcweb.jlab.org/wiki/images/a/af/Dipole_entrance.jpg Drawing ]] with measurements of the dipole entrance flange. [[https://hallcweb.jlab.org/wiki/images/c/c8/Dipole_entrance_3d.jpg 3d picture ]] of the dipole entrance.
 
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*[[https://hallcweb.jlab.org/wiki/images/9/9c/Shms_magnet_field_summary.pdf Summary table ]] of the SHMS magnets field properties. From Steve Lassiter file magnet_summary.doc on Sept 9th 2011.
 
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*Horizontal bender magnet dimensions (Mike Fowler on Sept 12th, 2011): [[https://hallcweb.jlab.org/wiki/images/a/a0/Bender_Dimensions_topview.jpg Top view]] , [[https://hallcweb.jlab.org/wiki/images/c/c7/Bender_Dimensions_3d.jpg 3-D view]], a few more views of the H bender from 2010, [[Media:Hb_topview.png|top view]], [[Media:Hb_topview2.png| top view at the smallest spectrometer angle]], [[Media:Hb_frontface.png| front face view]], [[Media:Hb_sideview1.png|side view]], [[Media:Hb_sidesectional.png| side sectional view]], [[Media:Hb_topsectional.png| top sectional view]], [[Media:ScreenShot112.jpg| view of aperture]]
 
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*Dipole apertures used in the MC model: The following figures describe how to calculate the parameters required to describe the dipole apertures in the MC. The dipole effective length is divided into 8 equal segments and the aperture center and inclinations are calculated at each of these segments. The inclinations angles are shown in [[Media:angles.png| angles]], and the drift distances and offsets of the center of the aperture with respect to the central trajectory are shown in [[Media:shms_geometry_2.png| table of offsets]].
 
  
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= SNAKE =
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[[https://hallcweb.jlab.org/wiki/images/3/3b/1st_order_summary.txt Comparison of 1st order matrix elements from Dave G. COSY fits and John LeRose tech note]]
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== Field maps of magnets ==
 
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*The Horizontal Bender
 
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**The integral field needed for 3 deg bend is 1.9211 Tm.
 
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**From map file, ''MSU_Bender.map'', the maximum integral field along a straight path is 1.92929 Tm with B_max=2.4768 T giving  L_eff= 0.7789m. So need a factor of 0.996 to scale map toget field for 3deg bend.
 
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*Dipole
 
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**The integral field needed for 18.4 deg bend is 11.783 Tm for integration along the path of the particle, L_arc, which is incident perpendicular to the field.  The difference between the L_arc and the straight line L_eff is L_arc/L_eff = theta/sin(theta)=1.017 for theta=18.4 deg. So need integral field along a straight path of 11.586 Tm.
 
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**From map file, ''shmsD2008.map'', B_max=4.7907 and Int(Bdl) = -13.67883 so L_eff=2.855. So need a factor of 0.8478 to scale map  to get field for 18.4 deg bend.
 
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* Quadrupoles
 
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**From map file, ''Q1_coldiron.map'',Max Bz/r= 10.791 and Int(Bz/r*dl) = 19.9049  for L_eff= 1.844 at r=20cm
 
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**From map file,''Q23nc6.map'', Max Bz/r=14.41324 and Int(Bz/r*dl) = 23.04041 for L_eff=1.5985 at r=31cm
 
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**Determine the scale factors for the quads to given desired 1st order optics.
 
  
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== Determine the magnet setting for 11 GeV/c ==
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===Aperture study===
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*Fix the map scale factor for the HB and Dipole fields at 0.996 and 0.8478 .
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* [https://hallcweb.jlab.org/wiki/index.php/Image:Apperture1.png Aperture 1], compared 20cm target at 20 deg with: (top panel), the blue points show the distribution when all apertures are included, while the red points are with no dipole apertures and no HB mechanical apertures. (Bottom panel), blue is same as above and the red show distributions with no dipole apertures, no HB apertures and no Q1,Q2,and Q3 Mech apertures, ie only apertures included are the Q1, Q2, Q3 magnetic centers.
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*Determine the scale factors for the quads, by modifying them so that (xfp|xptar)=0, (yfp|ytar)=1.634 and (yfp|yptar)=0 in 1st order matrix. Found scale factors are  -0.792092,0.845324,-0.526535 .
 
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* 1st order Matrix from target to focal plane has D/M = -1.09:
 
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{|border="1" align="center"
 
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!  !!xtar !!  xptar !!  ytar !!  yptar!! delta
 
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|-
 
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!xfp  || -1.501|| -0.002 ||-0.024 ||-0.054 || 1.634
 
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|-
 
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!xpfp|| -0.049 ||-0.663 || 0.001|| 0.002 || 0.310
 
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|-
 
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!yfp || -0.004 ||-0.002 ||-1.634|| -0.001 ||-0.025
 
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|-
 
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!ypfp || 0.000 || 0.003 ||-0.277|| -0.623 || 0.020
 
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|}
 
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*With new scale factors:
 
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** Q1 Max B = -1.7093 Int(Bdl) =  3.153304 Int(B/rdl) = 15.76652 at r=0.20m  L_eff= 1.844
 
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** Q2 Max B =  3.778  Int(Bdl) =  6.03996  Int(B/rdl) = 19.4736  at r=0.31m L_eff=1.5985
 
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** Q3 Max B = -2.3536 Int(Bdl) = 3.76275  Int(B/rdl) = 12.1316  at r=0.31m L_eff=1.5985
 
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** Overall path length = 18.10325m for central track
 
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*For comparison to COSY, Dave Gaskell optimized for (xfp|xptar)=0, (yfp|yptar)=0  and D/M=-1.09
 
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** Q1=-2.128585 T  at 25cm which at 20cm is q1 = -1.7028 using L_eff = 1.879m.
 
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** Q2= 4.342608 T  at 35cm which at 31cm is q2 =  3.8463 using L_eff=1.64m.
 
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** Q3=-2.805149 T  at 35cm which at 31cm is q3 = -2.484  using L_eff=1.64m.
 
  
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== Study of changing the vertical offset of dipole ==
 
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*Ran SNAKE with set of random trajectories for point target with -0.055 < xptar < 0.055, -0.030 < yptar < 0.040 and 8.8 < momentum < 13.2 GeV/c.
 
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*Input deck to SNAKE has 26 endplanes. An endplane is a position within SHMS where the the positions and angles are recorded. If the track goes outside the SHMS good volume then a flag is set to indicate a failed track and the positions and angles at the location between the endplanes is recorded.
 
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*Compared an vertical offset of 20cm and 26cm. For each offset the distance between the centerof the dipole and the focal plane center is recalculated.
 
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**1D Plot of number of tracks which failed for each endplane number for offset of [https://hallcweb.jlab.org/wiki/images/3/31/A_endplane.gif 20cm] and [[https://hallcweb.jlab.org/wiki/images/e/e0/C_endplane.gif 26cm]] . Endplane 6 is HB physical exit. Endplane 10 is Q1 physical exit. Endplane 19 is Dipole physical entrance. Endplane 23 is Dipole physical exit.
 
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**1D Plots of target xp,yp, delta and solid angle vs delta with for offset of [[https://hallcweb.jlab.org/wiki/images/b/b9/A_tar.gif 20cm]] and [[https://hallcweb.jlab.org/wiki/images/f/f1/C_tar.gif  26cm]] . The black line is all tracks. The blue line is failed tracks.  The red line is passed tracks. The solid angle is calcualted by the ratio of passed tracks to total tracks mutliplied by 0.11*0.07*1000 (the thrown solid angle in msr at each delta).
 
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**2D Plots of target xp/delta, yp/delta and xp/yp for offset of [[https://hallcweb.jlab.org/wiki/images/6/62/A_2dtar.gif  20cm]] and [[https://hallcweb.jlab.org/wiki/images/3/3c/C_2dtar.gif  26cm]] .
 
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**2D Plots of focal plane x/y, xp/yp, yp/y and xp/x for offset of [[https://hallcweb.jlab.org/wiki/images/1/1d/A_fp.gif  20cm]] and [[https://hallcweb.jlab.org/wiki/images/4/4e/C_fp.gif  26cm]] .
 
  
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== Study of changing the vertical opening of the HB ==
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* [https://hallcweb.jlab.org/wiki/index.php/Image:Apperture2.png Apertures 2], same for 40 cm target at 40 deg.
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*[https://hallcweb.jlab.org/wiki/images/0/0e/HB_Vacuum_Bore_Change.jpg Drawing] of the proposed change by Mike Fowler on Sept 28th.
 
  
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= COSY =
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* [[Media:Aperture3.png | Apertures 3]], Here in the bottom panel, only the HB apertures and Q1,Q2, Q3 mechanical apertures are removed. This is the minimal set of apertures which have to be turned off to get the distributions similar to the pre 2009 distributions. It should also be noted that this is the set of apertures is what existed in the pre 2006 mc_shms.f
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[[https://hallcweb.jlab.org/wiki/images/f/f7/Gaskell_shms2009.pdf Dave G. notes on 2009 shms studies]]
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 +
 
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* Acceptance for the no aperture (other than Q1,2, and 3 magnetic center apertures) is 4.6 msr
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===Collimator study ===
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* Run COSY based MC with target of length +/-10cm at 20deg. Use a 26cm offset in the dipole with 23cm opening in HB.
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* [[ Media:collimator1_0.08.png | Plot1]],  [[ Media:collimator1_0.12.png | Plot2]]of the  vertical position versus the horizontal position at Q1 entrance.  In the bottom right plot the red are events which are accepted up to the dipole entrance. The blue are those events which fail in the dipole. Plot1 is for D/M=0.08, Plot2 is for D/M=0.12, cut on delta -10<delta<22
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* [[Media:delta_acc_0.08.png |Plot1]], [[Media:delta_acc_0.12.png |Plot2]] of solid acceptance versus delta for cuts in the vertical acceptance at the entrance of Q1 for events with vertical position at Q1 less than 7 (magenta) , 9 (blue), 11 (green), 13cm (red) and no cut (black). The no cut acceptance was assumed to be 4 msr. Plot1 for D/M=0.08 and Plot2 for D/M=0.12, no delta cut is applied
  
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[[https://hallcweb.jlab.org/wiki/images/3/3b/1st_order_summary.txt Comparison of 1st order matrix elements from Dave G. COSY fits and John LeRose tech note]]
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* [[Media:collimator2_0.08.png |Plot1]], [[Media:collimator2_0.12.png |Plot2]] of vertical position vs horizontal position at Q1 entrance for events with vertical position at Q1 less than 7 (green) , 11 (magenta), 13cm (blue) and no cut (red). Plot1 is for D/M=0.08 and Plot2 is for D/M=0.12, cut on delta -10<delta<22
  
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= SLITS & COLLIMATORS =
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__FORCETOC__
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*[[http://www.jlab.org/Hall-C/upgrade/SHMS_OPTICS/shms_collimator.pdf Sieve slit placement & design (T. Horn)]]
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[[Category:SHMSinfo]]
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== SLITS and COLLIMATORS ==
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Moved to [[Collimators and Slits for SHMS | Collimators and Slits for SHMS]]
  
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= Detector Positions =
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== Detector Positions ==
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*[[http://www.jlab.org/Hall-C/upgrade/HALLC_12GEV/shms_beam_envelope.html table of detector positions]]
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Moved to [https://hallcweb.jlab.org/wiki/index.php/Detector_Locations_in_SHMS Detector_Locations_in_SHMS] location
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*[[ Media:SHMS_Detector_Coordinates_110921.pdf | New table from Howard updated on (09/21/2011)]]
 

Latest revision as of 10:54, 18 February 2013

Meetings

SHMS Characteristics

Drawings of magnets

Study of the SHMS resolution

  • Study of the SHMS resolution.

SNAKE

Moved Snake section here.

COSY

[Dave G. notes on 2009 shms studies]

[Comparison of 1st order matrix elements from Dave G. COSY fits and John LeRose tech note]

Aperture study

  • Aperture 1, compared 20cm target at 20 deg with: (top panel), the blue points show the distribution when all apertures are included, while the red points are with no dipole apertures and no HB mechanical apertures. (Bottom panel), blue is same as above and the red show distributions with no dipole apertures, no HB apertures and no Q1,Q2,and Q3 Mech apertures, ie only apertures included are the Q1, Q2, Q3 magnetic centers.


  • Apertures 3, Here in the bottom panel, only the HB apertures and Q1,Q2, Q3 mechanical apertures are removed. This is the minimal set of apertures which have to be turned off to get the distributions similar to the pre 2009 distributions. It should also be noted that this is the set of apertures is what existed in the pre 2006 mc_shms.f


  • Acceptance for the no aperture (other than Q1,2, and 3 magnetic center apertures) is 4.6 msr

Collimator study

  • Run COSY based MC with target of length +/-10cm at 20deg. Use a 26cm offset in the dipole with 23cm opening in HB.
  • Plot1, Plot2of the vertical position versus the horizontal position at Q1 entrance. In the bottom right plot the red are events which are accepted up to the dipole entrance. The blue are those events which fail in the dipole. Plot1 is for D/M=0.08, Plot2 is for D/M=0.12, cut on delta -10<delta<22
  • Plot1, Plot2 of solid acceptance versus delta for cuts in the vertical acceptance at the entrance of Q1 for events with vertical position at Q1 less than 7 (magenta) , 9 (blue), 11 (green), 13cm (red) and no cut (black). The no cut acceptance was assumed to be 4 msr. Plot1 for D/M=0.08 and Plot2 for D/M=0.12, no delta cut is applied
  • Plot1, Plot2 of vertical position vs horizontal position at Q1 entrance for events with vertical position at Q1 less than 7 (green) , 11 (magenta), 13cm (blue) and no cut (red). Plot1 is for D/M=0.08 and Plot2 is for D/M=0.12, cut on delta -10<delta<22

SLITS and COLLIMATORS

Moved to Collimators and Slits for SHMS

Detector Positions

Moved to Detector_Locations_in_SHMS location

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