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--- group_secar2.0 [2018/09/12 15:42]
wagner [Impact of Lenght Change in Quadrupole 2]
+++ group_secar2.0 [2018/09/13 16:01]
wagner [Optics misalignments]
@@ Line 2: / Line 2: @@
 -- by Alex, Nadeesha and Louis --
 ===== DAY1=====
@@ Line 28: / Line 29: @@
 {{ :reaction_kinematics.png?400 |}}
-Reaction summary for <sup>45</sup>V+p→γ+<sup>46</sup>Cr, E<sub>kin</sub>(<sup>45</sup>V)=135 MeV\\
+Reaction summary for <sup>45</sup>V+p → γ+<sup>46</sup>Cr, E<sub>kin</sub>(<sup>45</sup>V)=135 MeV\\
 The maximum γ energy is 8.481 MeV. The minimum γ energy is 7.249 MeV.\\
 The maximum <sup>46</sup>Cr energy is **132.634 MeV**. The minimum <sup>46</sup>Cr energy is **131.402 MeV**. The maximum <sup>46</sup>Cr angle is **0.13 degrees**.\\
@@ Line 39: / Line 40: @@
 {{ :dipole46cr13.png?400 |}}
+----
 ===== DAY2 =====
@@ Line 77: / Line 79: @@
 This emittance grow is possibly due to the optics aberrations. That is because the input COSY file does a 4th-order-calculation. Also the measured points don't fit the parabola ideally, i.e. the optics is non-linear.\\
+----
 ===== DAY3=====
-==== Impact of Lenght Change in Quadrupole 2 ====
+==== Impact of Lenght Change of Quadrupole 2 ====
 The effective length of Q2 was reduced by 3% to 0.291m with the drift lenghts before and after increased by 0.0045m.\\
@@ Line 84: / Line 87: @@
 As an educated guess we changed the gradient of Q2 by 3% to compensate the length reduction. The resolving power recoverd to ~400.\\
-This Q2 gradient was then used as the starting value for the fit routine, that minimized the inverse of the resolving power. Additionally the gradients of Q3 and Q4 were set as free parameters of the fit, too. The best fit value after 38 steps was 463, wich is even **5% better!** then the original resolving power. Off course then one has to check if the max angle and energy acceptance is still met. The fit values for Q",Q3 and Q4 stayed close to the starting values so one has to keep in mind that the fit routine might not have discovered a global minimum but only a local one.
+This Q2 gradient was then used as the starting value for the fit routine, that minimized the inverse of the resolving power. Additionally the gradients of Q3 and Q4 were set as free parameters of the fit, too. The best fit value after 38 steps was 463, wich is even **5% better!** then the original resolving power.\\
+Off course then one has to check if the max angle and energy acceptance is still met. The fit values for Q2,Q3 and Q4 stayed close to the starting values so one has to keep in mind that the fit routine might not have discovered a global minimum but only a local one.
 {{ :fitted.png?400 |}}
+----
+===== DAY4=====
+==== Optics misalignments ====
+**Beam position. Longitudinal offset.**
+We populated "X-θ" phase-space with rays distributed on the border of ellipse by the loop:
+<code>
+LOOP PHI 0.0 360 5;
+SRXX:= XX*COS(PHI*3.14159/180);
+SRAX:= AX*SIN(PHI*3.14159/180);
+ENDLOOP;
+</code>
+Rays in another planes are on-axis:
+<code>
+SRYY:= 0.0;
+SRAY:= 0.0;
+SRDE:= 0.0;
+</code>
+Created loop for target position. Observed piece-wise curve for resolution vs target offset (meters) (see figure below) in case of 4th order calculation. If order reduced to the 1st, than curve is smooth, but maximum resolution is shifted.
+{{ :target_offset.png?450 |}}
+The resolution drops by 5% at the offsets (-5 mm, +7 mm).\\
+**Beam position. Transverse offset.**\\
+{{ :transv.png?450 |}}
+The resolution drops by 5% at the beam offsets (-0.8 mm, +0.5 mm). The offset is of the beam half-size order. \\
+**Dipole 4 position. Transvers offset**\\
+{{:transvers_shift_b4.jpg?450|}}\\
+**Dipole 4 position. Longitudinal offset**\\
+{{:longitudinal_shift_b4.jpg?450|}}\\
+==== Recoil tracking in SECAR ====
+**<sup>45</sup>V+p → γ+<sup>46</sup>Cr**
+Beam is set to 132MeV <sup>46</sup>Cr<sup>14+</sup>\\
+<code>
+RP 132.0 46*PARA(1) 14*PARA(2);
+{Design acceptances, depends on kinematics of a specific reaction!}
+XX:=0.0005;
+AX:=0.01726;
+YY:=0.0005;
+AY:=0.01726;
+DE:=0.0047;
+</code>
+Recoil beam fits the SECAR very well.
+{{ :46cr_recoil_in_secar.png?300 |}}
+----
+THANK YOU FOR VISITING OUR PAGE

JINA-CEE ION OPTICS SUMMER SCHOOL: JIOSS 2018

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