P42 + K12 BEAM TUNING PROCEDURE
|
P42 + K12 BEAM TUNING PROCEDURE
revised for 1998 |
| -> | Check the horizontal, vertical reference positions of
BSM 241105 (~26m upstream of T4): IM(122) T STEP(3) , (4) = 63, 65 (mm), respectively |
| -> | Set nominal T4 'wobbling'; Select T4 target head=3 (200 mm Be) for nominal-intensity beam P42, or T4 target head=2 (300 mm Be) to reduce intensity by factor ~0.75; Check flux on BSI (T4) = NORM 2 (nominally = 6 * 1012ppp), combined 'symmetry' (position and angle) of proton beam incident onto T4 >80 % (SPS Page 1); ask PCR to adjust sharing and resteer if necessary. |
| 1. | Scan T4 'spot' (BBS/BSI (T4)), from -2.0 to +2.0 mm in steps of 0.2 mm, and 'angle' (asymmetry) |
| -> | Load file P42.4, P42.3, P42.2, P42.1,
P42.5, (H-, V-magnification from T4 to T10 = +0.333, 0.30, 0.27, 0.25, 0.222, -1.0 ; focusing for po =444.0 GeV/c, i.e. dpo/po = -1.33 %). |
| 2. | Select TAX 7: large range, TAX 8: medium range and open to positions: +61, +101 mm ([Phi]=6.0, 2.0 mm apertures, respectively, corresponding to acceptance angles : xo' = yo' ~= ± 0.05 mrad.) and observe proton beam flux on BSI (T10) and BSI 769 (Ti) = NORM10. |
| -> | Count 'Transmission' onto BSI(Ti)/NORM 2 ~= 1.0 * 10-2 (T4 head=3), or ~= 7.5 * 10-3 (T4 head=2). |
| 3. | Check horizontal alignment of beam with TAX 7+8 : Starting from nominal T4 'wobbling'settings, double scan B1 (2MTNH) (= B3 of target station T4) and B2 (MSNH) in ± 7 steps of : +10 A. and -9 A. (factor -0.9 ) - for B1 <800 A. (H8=-ve. momenta), +14 A. and -9 A. (factor -0.65) - for B1=-1071.8 A. (H8=+180 GeV/c), respectively, (dx = -1.2 mm at TAX 8; dx = 0, dx' = -0.06 mrad. at T4).
|
| -> | A significant displacement of the beam by Dx at TAX 8
for the nominal setting of B1 can be corrected by changing the horizontal
reference position
of BSM 241105 [IM(122) STEP(3)] by -1.3 Dx and asking PCR to resteer.
|
| 4. | Vertical positions of TAX 7 and TAX 8 : Set TAX 7 to position -139 mm (40 mm * 20 mm aperture) and scan TAX 8 ([Phi]=2.0 mm) from +93 to +109 in steps of 1 mm. Select the position corresponding to the centre of the distribution measured at ± 5 mm displacement. |
| 5. | Scan TAX 7 ([Phi]=6.0 mm) from +55 to +67 in steps of 1 mm, to find the centre of TAX 7 w.r.t. TAX 8. |
| -> | Set TAX 7+8 to positions: +61, +101 mm as in 2.,
corrected for any offsets found in 5. and 4.,
respectively. This defines the reduced-intensity proton beam, used for 6. - 15. and 26. - 27. |
| 6. | Horizontal steering to C1 and C3 : With nominal B3 (MSNH) =+1308.4 A. and B4 (4 MBWT) =B5 (MBWH) =+1010.8 A., close C1 to ±1 mm and double scan B2 (MSNH) and TRIM3 in ± 6 steps of +3.0 A. and -3.6 A. (factor -1.2), respectively, (dx = - 1.3 mm at C1, 0 at C3). Reopen C1 to ±40 mm. |
| 7. | Close C3 to ±2 mm and double scan B2 and TRIM3 in ± 6 steps of +4.0 A. and +0.9 A. (factor +0.225), respectively, (dx = +2.4 mm at C3, 0 at C1). Reopen C3 to ±40 mm. |
| 8. | Vertical steering to C2 and C4 : With TRIM 2 =0, close C2 to ±1 mm and double scan TRIM1 and TRIM4 in ± 6 steps of +3.0 A. and +1.0 A. (factor +0.33), respectively, (dy = -1.9 mm at C2, 0 at C4). Reopen C2 to ±40 mm. |
| 9. | Close C4 to ±1 mm and double scan TRIM1 and TRIM4 in ±6 steps of +2 A. and +12 A. (factor +6.0), respectively, (dy = +1.0 mm at C4, 0 at C2). Reopen C4 to ±40 mm. |
| 10. | Horizontal steering to C7 and centre of B10
aperture: With TRIM5 (MDSH) = -30 A. (see 11.), close C7 to ±2 mm and scan B7 (9 MBNH) from -1280 to -1273 in steps of +1.0 A. (dx = -1.8 mm at C7, ~0 at B10). Reopen C7 to ±40 mm. |
| 11. | With nominal B8 (2 MBNH) =-1596.0 A., B9 (2 MBNH) =+558.2
A.,
TRIM 8 =0, check centre of beam in horizontal aperture (±28 mm) of
B10,
counting BSI(T10)/N2: scan TRIM5 from -60 to 0 in
steps of +5 A. (dx = -3.4, -4.8 mm at B10, -0.4 mm at C7,
0
at T10, +2.8, +3.7 mm at TAX18). If it is decided to change TRIM5, repeat 10.. |
| 12. | Vertical steering to C8 and centre of Q20 aperture
: Close C8 to ±2 mm and double scan TRIM6 =TRIM7 in ±5 steps of +2 A. (factor +1.0), (dy = +1.2 mm at C8, -4.4 mm at Q20, 0 at T10, +0.75 mm at TAX18). Reopen C8 to ±40 mm. |
| 12. | With TRIM9 =0 (see 15.), check centre of beam in vertical aperture (±48 mm) of Q20, counting BSI(T10)/NORM2: double scan TRIM6 =TRIM7 in ± 10 steps of +3 A. (factor +1.0), (dy = -6.6 mm at Q20). |
| -> | Steering onto KL target (T10) : Set T10 target head =1 and T10-COLLIMATOR =position 4 ([Phi]=15 mm aperture); set collimators: XCLD-P,-D,-C and CONVERTER =>in beam. Load file K12.1 and select mode KL (TAX17+18 = +59.5 mm). Count neutral beam on TRIG1/NORM10 or KL decays on QX= EXP14/NORM10 or HAC-2 = EXP18/NORM10. |
| 14. | Horizontal steering, with TRIM11= 0: scan TRIM10 over T10 from -60 to +60 in steps of +6 A. (dx = -0.2 mm at T10, -0.35 mm at TAX18). |
| -> | After a change of T4 'wobbling' , to correct for a
change of
trajectory from T4 through TAX7+8 and hence onto T10: With 'P0-SURVEY' disabled, double scan B2 and B3 in ±7 steps of +25 A. and -10 A. (factor -0.4), respectively, (dx =+0.6 mm at T4, dx' =-0.033 mrad.; dx =+0.2, +0.15 mm at T10, dx' =-0.1, -0.13 mrad.). |
| 15. | Vertical steering, with nominal B10 (MBNV) = -1206.0
A.
And B11 (MBNV)=-1393.0 A. (for +2.4 mrad. KL production angle): scan TRIM9 over T10 from -40 to +40 in steps of +4 A. (dy = -0.2 mm at T10, +0.7 mm at Q20, -0.4 mm at TAX18). If TRIM9 is changed significanly, repeat 13.. |
| -> | This is carried out with the full-emittace proton
beam: Update and enable 'P0-SURVEY'. Open TAX7, TAX8 to positions -49, -49 mm ([Phi]=9.6, 12.0 mm apertures, respectively, corresponding to: xo' = yo' = ± 0.27 mrad.), corrected for any off-sets found in 5. and 4.. Observe BSI (Ti)/NORM2 ~= 2.5 * 10-1 with T4 head 3 (200 mm Be) or ~= 1.8 *10-1 with T4 head 2 (300 mm Be). |
| -> | Count on QX =EXP14/NORM10 or HAC-2 =EXP18/NORM10. |
| 16. | Check horizontal, vertical steering onto T10 (repeat 14., 15.) and iterate with 17. : horizontal -, 18. : vertical - focusing. |
| 17. | Horizontal focus: double scan Q21 (2QNL - FH) and Q20 (2QNL - FV) in ҙ10 steps of +3.0 A. and -0.3 A. (factor -0.1), respectively,from +266 to +306 in steps of +2 A., ( dz(H) = -0.3 m, dz(V) = 0 at T10 ). |
| 18. | Vertical focus: double scan Q20 and Q21 in ±10 steps of +1.0 A. and -0.3 A. (Factor -0.3), respectively, ( dz(V) = +1.5 m, dz(H) =0 at T10 ). |
| -> | If substantial increases or decreases are required in the
strengths of both Q21 and Q20, it may be worth changing the
strengths
of all quadrupoles coherently according to a new file, focusing for
a
different 'nominal' proton momentum, po: dz(H)/dpo/po ~= -0.34 m/% , dz(V)/dpo/po ~= -8.4 m/% . |
| 19. | Scan T10 'spot' (BBS/BSI (T10)):
horizontally and
vertically from -6.0 to +4.0 in steps of 0.2 mm. Repeat scans with horizontal + vertical focus displaced upstream by dz(H) =dz(V) =-0.96 m from T10 onto BBS, changing (strengthening) Q21 by +9.6 +0.2 = +9.8 A. and Q20 by -0.8 -0.6 = -1.4 A. |
| 20. | Check effect of varying horizontal, vertical angles onto
T10 : Counting rate should show a flat plateau over ±14, ±9 mm free aperture for full-emittance beam at B10, for ±0.8, ±0.5 mrad. variations of the horizontal angle onto T10. This corresponds to ±15, ±10 A. in a scan of TRIM5 from -50 to -10 in steps of +2 A.; (c.f. 11.). |
| 21. | Counting rate should show a plateau (with slope ~ -0.2 mrad-1 for KL) over ±26 mm free aperture for full-emittance beam at Q20, for ±0.33 mrad. variations (around +2.4 mrad.) of the vertical (production-) angle onto T10. This corresponds to ±12 A. in a double scan of TRIM6=TRIM7 in ±10 steps of +2 A. (factor +1.0); (c.f. 13. ). |
| -> | Protect NA48 detectors : check H.V. of Drift Chambers switched off ! |
| -> | Set XCLD-P, -D, -C => out of beam. |
| -> | Observe centres: <x>, <y> of horizontal, vertical profiles of neutral (KL) beam on MWPC 1 and FISC 9 (-58 to +70 in steps of 4 mm), MWPC 2 and FISC 10 (-70 to +58 in steps of 4 mm), respectively. |
| -> | Count on QX = EXP14/NORM10 or HAC-2 =EXP18/NORM10. |
| 22. | Align KL-cleaning collimator (XCLD-C) : Set XCLD-C => in beam and observe centres of horizontal, vertical profiles. Correct displacements d<x>, d<y> w.r.t. <x>, <y> by displacing XCLD-C by: dx = -0.41 d<x>, dy = -0.41 d<y> and check profiles. Check its centre and ±4.4 mm plateau by scans of XCLD-C horizontal, vertical positions from -7 to +7 in steps of 0.5 mm w.r.t. positions found. |
| 23. | Align KL-defining collimator (XCLD-D) : Set XCLD-D => in beam and observe centres of horizontal, vertical profiles. Correct displacements d<x>, d<y> w.r.t. <x>, <y> by displacing XCLD-D by: dx = -0.16 d<x>, dy = -0.16 d<y> and check profiles. Check centre and ±3.1 mm plateau of XCLD-C w.r.t. XCLD-D by scans of XCLD-C horizontal, vertical positions from -5 to +5 in steps of 0.5 mm. |
| 24. | Check alignment of KS-proton collimator (XCLD-P)
w.r.t. KL beam: Set XCLD-D, XCLD-C => out; set XCLD-P ([Phi]=20 mm aperture) => in. Note its centre and ±5.2 mm plateau by scans of XCLD-P horizontal, vertical positions from -7 to +7 in steps of 0.5 mm w.r.t. positions last found for KS-proton beam , (39.). |
| 25. | Check positions of TAX18 and TAX17 : Scan TAX18 ([Phi]=8.0 mm KL aperture) from +51.5 to +67.5 in steps of 1 mm to check its centre and ±1.3 mm plateau for the KL beam. Scan TAX17 ([Phi]=10.8 mm KL aperture) from +51.5 to +67.5 in steps of 1 mm to check its centre and ±2.8 mm plateau for the KL beam. |
| 26. | Establish C1, C3; C2, C4 collimator settings :
In the P42 reduced-intensity proton beam, (TAX7, 8 = +61, +101 mm), and counting BSI(Ti)/NORM2, scan C1 (slit=2 mm) from -6 to +6 in steps of 2 mm and reopen C1; scan C3 (slit=4 mm) from -12 to +12 in steps of 4 mm and reopen C3. |
| 27. | Scan C2 (slit=2 mm) from -6 to +6 in steps of 2 mm
and reopen
C2; scan C4 (slit=2 mm) from -4 to +4 in steps of 2 mm and reopen C4. |
| -> | Define an attenuated, pencil proton beam ( <~
107 ppp) by setting TAX7 => +101 mm (0.8 m long Be
attenuator), TAX8 =+101 mm ([Phi]=2.0 mm), corrected for any off-sets
found
in 5. and 4. and closing collimator slits to : C1 => ±1 mm, C3 => ±2 mm; C2 => ҙ1 mm, C4 => ±1 mm , about the centres found in their respective scans, (26., 27.). |
| -> | Steering through TAX17+18 (K12) : Displace TAX17 ([Phi]=10.8 mm KL aperture) to : +59.5 -11.0= +48.5 mm and TAX18 ([Phi]=2.4 mm KS aperture) to : +59.5 +72.0 -11.0 = +120.5 mm, corrected for any off-sets found in 25.. These positions lie on a trajectory which by-passes the crystal at a parallel displacement of -11.0 mm below the KL beam axis. |
| -> | Set K12 CRYSTAL, XCLD-P, -D, -C and CONVERTER => out of beam. |
| -> | Disable 'P0-SURVEY' and load file K12.2 with B1 (MBNV) =+496.2 A., B2 (MBNV) = -203.0 A., B3 (2MCWV) = -140.8 A., B4, B5, B6, B7 = 0, Q1, Q2 = 0 to direct the attenuated, pencil proton beam along the 'by-pass' trajectory, counting TRIG1/NORM2 ~ 10-6. |
| 28. | Horizontal steering: scan TRIM5 from -40 to -20 in steps of +1 A. (dx = +0.7, +0.9 mm at TAX18, 0 at T10; c.f. 11., 20.). |
| 29. | Vertical steering: double scan TRIM6 =TRIM7 in ±6 steps of +2 A. (factor +1.0), (dy = +0.7 mm at TAX18, 0 at T10; c.f. 13., 21.). |
| -> | Choose the centred settings of TRIM5, TRIM6 =TRIM7 and observe the profiles of the attenuated, pencil proton beam on MWPC 1,2. |
| -> | Use P42 full-emittance proton beam, (TAX7, 8 = -49, -49 mm), as for 16. - 25., with 'P0-SURVEY' disabled ! |
| -> | Select K12 mode KS (file K12.1), TAX17=>-84.5
mm, TAX18=+59.5mm, corrected for any off-sets found in 25.;
set B5, B6, B7, [B8+9] => 0, XCLD-P, -D, -C and CONVERTER => out of beam. (Q1,Q2 focusing gives profiles * -1/2.7 at MWPC1, * -1/1.2 at MWPC2). |
| -> | Check 'calibration' of crystal movements; starting from the last aligned settings (x= -2.5 mm, y = -1.2 mm, [phi] = +27.6 o, a = -6.1 mrad.), iterate to find the optimum settings of the crystal goniometer positions and angles, counting the flux of protons passing via the TAGGER onto the KL axis: TRIG1/NORM10 (~=3 * 10-5). |
| -> | Alternatively, if TRIG1 saturates, the [pi]0-target [35 mm (CH2)n] can be inserted at the exit of the KL final collimator and the production of secondary particles counted in the detector, e.g. QX =EXP14/NORM10. |
| 30. | Tune vertical rotation angle : Search for the channeling condition: scan the vertical rotation angle of the crystal, [alpha], from -8 to -4 in steps of 0.2 mrad. The full width of the distribution is given by the horizontal size of the beam at the crystal ( dx = 2.0 mm) that can pass through the [Phi]=2.4 mm aperture in TAX18, via the relation: d[alpha] = 1/cos[phi] * |Dy'/Dx| * dx ~= 1.4 mrad., where Dy'/Dx ~= 0.6 mrad./mm. Select the central setting of [alpha] . |
| 31. | Tune vertical beam deflection angle : Vary the vertical beam deflection angle ( [theta] ): scan the horizontal angle of the crystal, [phi] , from +26 o to +29 o in steps of D[phi] = 0.2 o , corresponding to D[theta] = - 0.1 mrad. The width of the distribution is given by the spread in vertical angle of the beam impinging on the crystal ( dy' ~= 0.25 mrad.), via the relation: d[phi] = 2 |D[phi]/D[theta] | dy' ~= 1.0 o , where D[phi]/D[theta] ~= -2.0 o/mrad. Select the central setting of [phi] and check the vertical position of the beam on MWPC 2. |
| 32. | Adjust horizontal displacement : If a tail is seen in the distribution of [phi] , it may be interpreted as being due to protons entering or leaving the edge of the crystal beyond the roller at its upstream or downstream end, where the crystal ceases to be curved against the holder. Such an observation, together with an off-set, D[alpha] , in the value of [alpha] from the mean w.r.t. the value found for the opposite sign of [phi] , (see 34.), indicates that the horizontal position of the crystal should be displaced by: Dx (mm) = D[alpha] (mrad.) * R (m) sin [phi] ~= ±1.5 D[alpha] , for R =3.0 m, [phi] ~= + - 30[omicron] . Then rescan [alpha] according to 30.. |
| 33. | Tune vertical displacement : Scan the vertical displacement, y , of the crystal from -2.4 to +1.2 in steps of 0.4 mm. The full width of the distribution is given by the sum of the thickness of the crystal ( t =1.5 mm.) and the height of the beam ( dy = 2.0 mm.) that can pass through the TAX18 aperture : t + dy = 3.5 mm. Select the central setting of y. |
| 34. | 34. Tune vertical beam angle at T10 to crystal: Double scan TRIM6=TRIM7 in ±5 steps of +2 A. (factor +1.0). Select central setting (c.f. 29.). Rescan y , according to 33. and iterate if necessary. Then rescan [phi] , according to 31.. Observe the horizontal, vertical profiles of the transmitted proton beam on MWPC 1, 2. |
| 35. | 35.Tune crystal with opposite horizontal rotation
: With the same crystal, a second, symmetrical solution exists for the opposite horizontal rotation, [phi] ~= -29.8 o. Starting from this setting, scan a , [phi] and y according to 30., 31. and 33., (34.), respectively, and adjust x , if needed, according to 32.. |
| -> | Select the setting for +ve. or -ve. [phi], which yields the more regular profiles on MWPC 1, 2. |
| -> | Starting from status used to tune the crystal,
(file K12.1 with B5, B6, B7, [B8+9] = 0): count proton beam on TRIG1/NORM10 or secondary particles from the [pi]0-target in the detector, e.g. QX = EXP14/NORM10; observe horizontal, vertical profiles on MWPC 1, 2.
Steer through KL-defining collimator (XCLD-D) : |
| 36. | Vertical steering: scan B2 (MBNV) from -1440 to -1290 in steps of +15 A., corresponding to displacements of the beam defined by the crystal (±5 mm) by: dy = -1.0 mm at XCLD-D, (-1.2 mm at XCLD-C, -0.2 mm at KS-target, +7 mm at MWPC 2). |
| 37. | At the selected setting of B2, observe profile on MWPC 2.
Horizontal steering: scan TRIM1 (MDXH 80) from -240 to 240 in steps of +80 A. (dx = -1.0 mm at XCLD-D, -4.5 mm at XCLD-C, -5.0 mm at KS-target, -8 mm at MWPC 1). If the scan is flat, reset TRIM1 = 0 and observe profile on MWPC 1. |
| -> | Check steering of proton beam: scan XCLD-D horizontal and vertical positions from -5 to +5 in steps of 0.5 mm and reset to positions found in 23.. |
| Steer through KL-cleaning collimator (XCLD-C) : Set XCLD-C ([Phi] =37.2 mm aperture) => in beam at x, y positions aligned on KL beam (see 22.). |
|
| 38. | Vertical steering: double scan B3 (2MCWV) and
B2 (MBNV) in ±5 steps of +30 A. and +15 A. (factor +0.5),
respectively,
corresponding to displacements of the beam (±4 mm) by: dy =+1.3 mm at
XCLD-C, ( 0 at XCLD-D, +1.0 mm at KS-target, -2 mm at MWPC 2). If scan is flat, reset B3 to initial, file value =-1034 A., B2 as found in 35.. |
| 39. | Horizontal steering: with B4 (3MBPL, [Phi] =40 mm
aperture
in Fe core) set to +40 A. to sweep mu+ towards +ve. x,
scan TRIM2 (MDXH 80) from -250 to +250 in steps of +50 A.
(dx= -2.5 mm at XCLD-C, -3.6 mm at KS-target, -13 mm at MWPC 1). If scan is flat, reset TRIM2 =+146 A. to compensate stray field in aperture of B4. |
| -> | Check: scan XCLD-C horizontal and vertical positions from -7 to +7 in steps of 0.5 mm and reset to positions found in 22.. |
| 40. | Align Proton collimator (XCLD-P) With XCLD-D => out, set XCLD-P ([Phi] =6.0 mm aperture for proton beam) => in beam and scan XCLD-P vertical and horizontal positions from -5 to +5 in steps of 0.5 mm w.r.t. the positions last found. |
| -> | Alternatively: count the background on the
TAGGER halo counters to minimise this, once these have been aligned on the
beam; or: count the neutral (KS) beam after the proton beam has been steered onto the KS-target (41., 42., 43. below). Compare the selected positions with those noted for the KL beam, (24.). |
| -> | Steer onto KS-target (XTGU) : Set B5 (MBNV), B6 (MCWV), B7 (MTNV) to file values, KS-target to the last aligned settings (x= -0.5 mm, y= +0.4 mm); set XAKS- converter => out of beam (=calibration position) and set CONVERTER => in to count the neutral (KS) beam on TRIG1/NORM10. |
| 41. | Horizontal steering: scan TRIM3 (MDXH 80) from -56 to +40 in steps of +8 A. (dx =-0.2 mm at KS-target). |
| 42. | Vertical steering: double scan B5 and B6 in ±5 steps of +10 A. and +15 A. (factor +1.5), respectively, (dy = -0.2 mm at KS-target, dy' =0). |
| 43. | Observe centres: <x>, <y> of horizontal,
vertical
profiles with MWPC 1 and FISC 9 (-58 to +70 in steps of 4 mm),
MWPC 2 and FISC 10
(-78 to +50 in steps of 4 mm), respectively. These should be at the same position horizontally and at -8 mm vertically w.r.t. the centres of the KL beam (23.). Correct displacements d<x>, d<y> w.r.t. the wanted positions by displacing KS-target by: dx = -0.04 d<x>, dy = -0.04 d<y>. |
| -> | Repeat 41., 42., respectively, and check profiles. |
| -> | Focus onto KS-target : Count the neutral beam on TRIG1/NORM10 or AKS-L with Pb or Ir-crystal XAKS-converter in place = EXP6/NORM10 : |
| 44. | Double scan Q1 ( QNL(F)+QNL(D)) and Q2 (QTR(D)+QTR(F)) in ±8 steps of +4.0 A. and -0.8 A. (factor -0.20), respectively, (dpo/po = -0.37 %; or dz(H)~=+0.9 m, dz(V)~=+0.4 m at KS-target). |
| -> | Check horizontal, vertical steering onto the KS-target (repeat 41., 42.). |
| -> | Check focusing with separate
scan of Q1 or Q2 :
Q1 steps of +15 A. or Q2 steps of -1.0 A.
each cause shifts of the focii in the same ratio of 9/4 ,
(dz(H) = +0.81 m., dz(V) = +0.36 m.); [Note: Q1 steps of +15 A. and Q2 steps of +1.0 A. (factor +0.067) change the ratio of H- to V-magnification from the crystal to the KS-target (nominally = -1.5/-0.667 = +2.25) by ~ -6.5 % , without displacing the focii ( dz(H) = dz(V) = 0)]. |
| -> | Adjust KS beam w.r.t. KL : Select mode KL+KS. |
| -> | Count KS beam: AKS-L = EXP6/NORM10 or KS MONITOR = EXP2/NORM10. |
| 45. | Vertical angle of proton beam at T10 to crystal: Double scan TRIM6 =TRIM7 (P42) in ±5 steps of +2 A. (factor +1.0) on KL-plateau found in 21.. Set TRIM6=TRIM7 to maximum of KS (= setting found in 34., c.f. 29.). |
| 46. | Horizontal angle of proton beam at T10 to crystal:
Scan TRIM5 (P42) from -40 to -20 in steps of +1 A. on plateau found in 20.. Observe time-variation (spill shape) of KS (on T1.T2, KS-MONITOR and AKS) and KL (on BEAM COUNTER) and their ratio as a function of TRIM5 settings. Set TRIM5 to render the ratio as constant as possible over the spill, (c.f. 28.). |
| 47. | Record horizontal, vertical positions of P42-proton
beam at
exit of Q21, (18.8 m upstream of T10): scan BSM1 (H), (V) from 50 to 80 in steps of 2 mm and note positions for asymmetry=0, (c.f. nominal axis = 65 mm). |
| 48. | Record horizontal, vertical profiles of K12-proton beam onto the KS-target with FISC 7 (-0.4 to +1.6 in steps of 0.2 mm), FISC 8 (nominally at +69.8 - 30 mm vetical off-set = +39.8 mm: +38.0 to +40.0 in steps of 0.2 mm). |
| -> | Set FISCs out of beam and
'out-of-service' : FISC 1, 2, 3, 5, 6, 7 => -40 mm, FISC 8 => +20 mm (between KL and KS-proton beams), [FOR I=117,124; FMOT(I,#SBT)=1]; FISC 9, 10 => -70 mm. |
| -> | Retract the [pi]0-target, if it has been used to tune the KS-proton beam on the KL axis, (30. - 40. above). |
| -> | Update and enable 'P0-SURVEY'. |
| -> | Count KS-/KL-proton ratio (nominally = 2 *
10-5): either directly: T1.T2 (downscaled) = EXP3/NORM10, or via: 600*AKS-L(with aligned Ir-crystal converter) = EXP6/NORM10. This ratio is approximately proportional to the H-magnification of the P42 proton beam from T4 onto T10 and can be changed in steps of ~10% according to files: P42.4, P42.3, P42.2, P42.1, P42.5, H-magnification: +0.333, 0.30, 0.27, 0.25, 0.222, Rel. KS-/KL-proton ratio: 1.0, 0.90, 0.81, 0.75, 0.67, respectively.
|
| 49. | Retune beam after loading a new file: Horizontal, vertical steering of the proton beam onto T10: scan TRIM10, TRIM9, respectively, according to 14., 15.; check horizontal, vertical focusing, according to 17., 18., (19.); |
| 50. | - to reoptimise KL. Vertical, horizontal angles of the proton beam at T10: double scan TRIM6=TRIM7, scan TRIM5, respectively, according to 45., 46.; - to reoptimise KS. |