Hall A Tech Notes JLAB-TN-02-012
Contents
1. e_miss VS e th_rot e_miss VS e x_rot 16 14 12 10 a mr r tii E E 0 04 0 02 0 0 02 e_miss VS e ph_rot 0 04 0 02 0 0 02 0 04 e_miss VS e y_rot Figure 9 Emiss vs focal plane variables Also shown is the polygon cut to select events for Emiss optimization 19 A Optimization input file description A 1 Single arm optics The input files opt_off dat opt ytg dat opt ang dat and opt_dpk dat are used to input variables for the optics optimization Please see the examples given in my directory The first part of these files are the same Here is a sample opt y dat file dat_file l_off data db_in db_e99117_1_kin1 db_out db_itr_1 e0 1197 0 arm 2 th_0 19 985 sp_v_off 0 00047 sp_h_off 0 0023 target_angle 90 0 n_zreact T zreact_1 0 2000 zreact_2 0 1334 zreact_3 0 0667 zreact_4 0 0000 zreact_5 0 0667 zreact_6 0 1334 zreact_6 0 2000 n_ysieve T y_sieve_1 0 0378 y_sieve_2 0 0254 y_sieve_3 0 0129 y_sieve_4 0 0004 y_sieve_5 0 0121 y_sieve_6 0 0246 y_sieve_7 0 0371 n_xsieve T x_sieve_1 0 0785 x_sieve_2 0 0535 x_sieve_3 0 0285 x_sieve_4 0 0035 x_sieve_5 0 0215 x_sieve_6 0 0465 X_sieve_7 0 0715 npeak 4 3 3 2 3 3 3 3 3 4 3 3 5 20 te DER eee Dm ce 12 13 14 15 16 17 dat_file is the name of your data file new name of fort 51 db in is the starting database db_out is the name for the new optimized database e0 Beam energy in2. Dinka Dik pY r Gyn AQ D AA e y 25 s Pp where 6 6 lt wp In practice the basic variables ytg 0tg tg do not form a good set of variables to work with For a foil target not located at the origin of the target coordinate system Y g varies with ig In the case of a multi foil target tg calculated for a given sieve slit hole depends on yg Further all three variables depend on the horizontal and vertical beam positions 2peam and Ypeam On the other hand the interaction position along the beam Zreact and vertical and horizontal positions at the sieve plane sieve and Ysieve are uniquely determined for a set of foil targets and a sieve slit collimator These three variables are calculated by combining the basic variables defined above using the equations see fig 2 COS Ptg Zreact Ytg sin o diy LeamCot Oo dig 26 Ysieve Ytg Ltan Pig 27 Lsieve Ttg L tan big 28 The vertical coordinate x in the target transport coordinate system of the spectrometer is calculated using the beam position in the vertical direction vertical displacement of the spectrometer from its ideal position 64g and Zreact Note that beam variables are measured in the hall coordinate system centered at the center of the hall with 2 along the beam direction and vertically up 3 Experimental procedure A general set of tensors describing the entire y9 619 tg and ae space may be obtained by acqu
3. MeV arm Spectrometer number spectrometer that comes first in the data base is 1 and the other one is 2 In the new left right notation of espace spec_r 1 specl 2 th_0 central angle of the spectrometer see above angles measured on the left side of the beam line are positive sp_v_off Vertical offset of the spectrometer axis from the ideal hall center in meters in the spectrometer target coordinate system sp h_off Horizontal offset of the spectrometer axis from the ideal hall center in meters in the spectrometer target coordinate system target_angle Angle of the target foil with respect to the beam line 10 11 Total number of target foils N1 N1 lines containing z_react value of each target foil in meters in the hall coordinate system Total number of vertical columns in the sieve slit N2 N2 lines containing y_sieve value of each hole column in meters in the spectrometer target coordinate system Total number of horizontal raws in the sieve slit N3 N3 lines containing x_sieve value of each hole raw in meters in the spec trometer target coordinate system Number of peaks selected for optimization N4 You define these peaks when you run cuts_xxx_l kumac At the end of the execution of this kumac it prints the total number of peaks selected as nr of peaks N4 Case of opt _off dat opt_ytg dat and opt_ang dat N4 lines containing target foil number vertical column number and the horizonta
4. are polynomials in Xfp Consider for example Yjx1 m Y i Yki y C DEN 21 i l Thus the final expression for yg is m Yiri i pi k al Ytg gt EG Lp y fr P tp 22 j k l i 1 Mid plane symmetry of the spectrometer requires that for Yjx and Pigi k l is odd while for Dji and Tjx k l is even The optics matrix elements Cm are read from the database for ESPACE analysis An optics matrix line from the database is given below 0001 7 0170E 01 1 2796E 00 6 4398E 01 1 0002E 01 0 0000E 00 Y001 The Y in Y001 indicates that this is a yt matrix elements Similarly there are D P and T matrix elements that correspond to 6 and 6 respectively The first number in the line vary code is used during optimization to indicate the order in fp up to which C need to be optimized A vary code of 0 indicates that the corresponding line should not be changed during optimization The next three numbers give j k and l for the matrix element The real numbers are the CF matrix elements in the order of increasing i order in x fy The transfer tensors are obtained by the minimization of the aberration functions Yad ou yin y A y D eee 23 8 y where yf Yty lt Wy 6Note that the superscripts denote the power of each focal plane variable i ak gf 0 i yk gl 0 A 6 Sea Tiri pV fp tp Fras ra Seat Pitt toU ptp Prop o 24 where 6 6 lt we and f lt we and
5. espace_test_t kumac to analyze the data with your database 3 Make sure that the input file test dat has been updated with the correct values 4 Run optimize with argi kumac arg2 test 5 Now you are ready for the database test In paw run the kumac files test_off_l kumac test_ytg_1 kumac and test_ang_1 kumac Answer the ques tions and select cuts when prompted These kumacs will display y_tg and x sieve versus ph tg plots for the selected peaks on grids of sur veyed locations of these peaks You will also get a set of ps files labeled test_xxx_litr_n ps containing all the plots generated by the kumac files 4 2 2 Quantitative test 1 Follow steps 1 4 of the visual test 2 Execute the following steps for xxx off ytg and ang 16 In paw run cuts_xxx_l kumac Answer the questions and define cuts Note in the case of react_z vs y rot plots you need to define a polygon around the peak while in the case of x_sieve vs y sieve plots you only need to select one point at the center of each peak This kumac will generate i holes dat i 1 2 file s Use the peak information from these file s to update opt xxx dat See the appendix for a description of opt xxx dat files In espace analyze data using espace_xxxt kumac this will generate a fort 51 file containing input data for the test Copy fort 51 into the file name you are using in xxx_off dat Run optimize with argi xxx arg2 test You will get a file labeled 0 com
6. that a reference to an angular coordinate in this section should be taken to refer to the tangent of the angle in question e Hall Coordinate System HCS The origin of the HCS is at the center of the hall which is defined by the intersection of the electron beam and the vertical symmetry axis of the target system Z is along the beam line and points in the direction of the beam dump and is vertically up See Fig 1 e Target Coordinate System TCS Each of the two spectrometers has its own TCS A line perpendicular to the sieve slit surface of the spectrometer and going through the midpoint of the central sieve slit hole defines the z axis of the TCS for a given spectrometer 2 points away from the target In the ideal case where the spectrometer is pointing directly at the hall center and the sieve slit is perfectly centered on the spectrometer the z4 axis passes through the hall center For this case the distance from the hall center to the midpoint of the central sieve slit hole is defined to be the constant Zo for the spectrometer The origin of the TCS is defined to be the point on the zg axis at a distance Zo from the sieve surface In the ideal case the origin of the TCS coincides with the hall center The x axis is parallel to the sieve slit surface with tg pointing vertically down The out of plane angle sg and the in plane angle g are given by gu and Tis respectively See Fig 2 3 ZERIE 1 181 m ZE S 1
7. 1 Getting things ready The optimization routine optimizes spectrometer focal plane offsets off y co ordinate at the target ytg 0 and angles at the target ang kinematically corrected momentum dpk and emiss emi The detector optimizations are 13 handled by espace and other routines and are described else where In order to test an existing database or to optimize the database one needs the following e A data set At lower momenta lt 1GeV one should perform an elastic delta scan with a heavy nuclear target of several thin foils covering the Ytg acceptance of the spectrometer Data should be taken at each setting with and without the sieve slits The sieve slit data is needed for angle and position optimizations Tight cuts on the elastic peak help eliminate sieve slit punch through events in this case Open collimator data which does not suffer any degradation of momentum resolution due to sieve punch through and edge scattering can be used for momentum optimization At higher momenta it is not possible to use elastic scattering from a target like 12C due to low cross sections In this case quasi elastic scattering 17C foil stack can be used for angle and position optimizations While this data is not as clean as in the elastic case such a measurement takes less time than an elastic delta scan because the whole focal plane is covered by one or two momentum settings of the spectrometer Since single arm data do not define
8. 178 m Figure 1 Hall Coordinate System top view Scattered electron Sieve plane Spectrometer central ray Beam Hall center Figure 2 Target coordinates for electrons scattering from a thin foil target as seen from above L is the distance from Hall center to the sieve plane while D is the horizontal displacement of the spectrometer axis from its ideal position Spectrometer central angle is denoted by Oo Note that tg and sieve are vertically down into the page e Detector Coordinate System DCS The intersection of wire 184 of the VDC1 U1 plane and the perpendicular projection of wire 184 in the VDCI1 V1 plane onto the VDC1 U1 plane defines the origin of the DCS is parallel to the short symmetry axis of the lower VDC see Fig 3 2 is perpendicular to the VDC1 U1 plane pointing vertically up and is along the long symmetry axis of the lower VDC pointing away from the center of curvature of the dipole see Fig 4 Y V1 VDC plane ye a L NE et ee y 184 V1 184 U1 U1 VDC plane Figure 3 Detector Coordinate System top view VDC 2 a v2 VDC 1 ZA Vi Ul x gt Figure 4 Detector Coordinate System side view Using the trajectory intersection points Pvde n where n 1 4 with the four VDC planes the coordinates of the detector vertex can be calculated accordin
9. JLAB TN 02 012 Optics Calibration of the Hall A High Resolution Spectrometers using the new optimizer Nilanga Liyanage nilangaQ jlab org July 18 2002 1 Introduction Most up to date version of this document can be found at http www jlab org nilanga physics optics ps The Hall A High Resolution Spectrometers are an identical pair of QQDQ magnetic spectrometers with optical properties that are point to point in the dispersive direction The optics matrix elements allow for the reconstruction of the interaction vertex in the target from the coordinates of the detected particles at the focal plane This document describes the optics calibration procedure used to determine the optics matrix elements The first part of this document describes the basics of optics optimization The second part of the document describes the testing procedure of the available data bases while the last part is a step by step user manual for the newly written optimize optimization routine The input data for optimize is supplied by The Hall A event analyzer ESPACE This manual assumes that the user has a good working knowledge of ESPACE Optics matrix elements for both spectrometers have been optimized over the full ranges both spectrometers This optimization has been performed for the normal tune of the HRS pair The spectrometer tune and hence spectrometer optics is very sensitive to the ratio of the magnetic field in the Dipole to the magnetic fields in the
10. a sharp peak in momentum for quasi elastic scattering one has to use a series of coincidence 2C ee p runs for the momentum optimization e A startup database Doug Higinbotham maintains a library of generic optics databases e The Official version of espace All kumac files assume the official left right notation of espace If you are using an old version of espace with the electron hadron notation change all the kumac files accordingly and re compile your es pace with the routines from work halla e89003 nilanga optimize espace_changes replace your espace_lib f or spectra f with these routines and recom pile espace e Optimization code Copy everything from work halla e89003 nilanga optimize optimize_src to your directory Add the following lines to your login file if 0SNAME Linux then use root 2 23 endif set path ROOTSYS bin path setenv LD_LIBRARY_PATH usr dt lib ROOTSYS 1ib e Login to a Jlab CUE Linux machine like ifarml2 and cd to your directory e type make 14 e this will give you an executable called optimize e Note that the include file locations in optimize cpp have been hardwired in for ifarml machines To run the program you need to give the command optimize with two arguments gt optimize argi arg2 arg1 can be off ytg ang dpk or emi for different reconstructions while arg2 can be test or optimize The first time you run optimize for each spectrom
11. ation the pro gram will generate the new database and write out 0 compare_xxx and 1_compare_xxx files For each peak you have selected these files will compare the surveyed value xx_0 to the average value xx_av of the re constructed variables here xx stands for y ph and th before and after optimization respectively 6 Execute test_xxx_l kumac in paw to test the new data base and to generate plots 4 4 Emiss Optimization The missing energy for a coincidence experiment is calculated using the mo menta measured by the two spectrometers Therefore the momentum opti mization should in principle optimize the width of the missing energy peak However in cases where the momentum was optimized at a lower momentum and one of the spectrometers is set at a higher momentum for coincidence kine matics Emiss might have correlations with the focal plane variables In this case Emiss can be optimized by optimizing momentum matrix elements D el ements for the spectrometer with higher momentum while keeping the matrix elements of the other spectrometer constant For the Emiss optimization one needs to choose an e e p coincidence data set with a sharp Emiss peak For example the two body breakup peak for the 3He e e p reaction 1 Analyze data with the database optimized in the previous steps using ana_emiss kumac 2 Generate a histograms of Emiss vs focal plane variable 6 94 Lrot Yrot and rot of the spectrometer that need optim
12. eter arg must be kumac and arg2 must be test This will generate zreact and sieve slit grid kumacs needed at subsequent steps of the optimization or testing e Sample files for optimization A complete set of sample files required for optimization can be found in work halla e89003 nilanga optimize optimize_example Here is a short description of the files you need The sample files and the descrip tion given here are for the left spectrometer For the case of the right spectrometer just replace l by r in the sample files espace kumac files These files are named espace_xxx_l kumac where xxx stand for off ang ytg dpk and emi for the optimization given above Another espace kumac espace_test_Il kumac is used for testing the databases Before you start go through the sample kumacs carefully and change the file names etc to match your situation The optimization se quence is labeled by the iteration number itr which is given as an argument at the execution of the kumac When the kumac files are executed the run number also has to be supplied as an argument For example espace gt exec espace_ang_1 kumac nrun 1336 itr 1 paw kumac files There are two sets of paw kumac files you need the first set named test_xxx_t1 kumac is for testing the reconstruction of different coordi nates using a given database The second set named cuts_xxx_l kumac are used to define cuts and generate input files for optimization Fortra
13. g to Pvude 3 Pude l t 1 an Ni db 1 tan n2 Pudc 4 Rude 2 dy 1 Odet RT tan 7 tan no 3 1 det B tan n tan n2 4 1 Ldet a Pude 1 Pude 2 ditan ng and 5 1 Ydet V2 Pvde 1 Dude 2 d tan ne 6 where the distances d1 and d2 are defined in Fig 4 These equations may be derived based on the following assumptions the VDC sense wires are oriented at 45 with respect to the wire frame the wires are positioned in planes the wire planes are parallel to each other and are separated by known distances the location of the center of each wire plane is known Any deviation from the above assumptions leads to offsets in the DCS coordinates These offsets are corrected when the focal plane vertex is calculated Transport Coordinate System TRCS at the focal plane The TRCS at the focal plane is generated by rotating the DCS clockwise around its y axis by 45 Ideally the 2 of the TRCS coincides with the central ray of the spectrometer However due to the deviations mentioned above the TRCS used by ESPACE can differ from the ideal spectrometer Transport Coordinate System The transport coordinates can be expressed in terms of the detector coor dinates by Odet tan Po Oira 7 tra Ta baertan po det rn e 8 Pera COS Po aetsin po 8 Lira LdetCOS po 1 tratan po 9 Ytra Ydet S N Po PtraLdet 10 whe
14. iring data that covers the full range of these variables In the past these data were achieved in practice by performing the following series of calibration experiments at a nominal incident energy of 845 MeV electrons were scattered from a stack of thin C targets covering the yz acceptance of the spectrometer for each of the yg runs above five open collimator measurements were performed at a values varying from 4 5 to 4 5 in steps of 2 so that the C elastic peak moves across the focal plane all of the above measurements were then repeated with a sieve slit col limator that had 49 holes with well defined Zsieve and Ysieve values see Fig 7 The holes were drilled in a rectangular grid perpendicular to the plane of the sieve slit and parallel to x and y coordinates at the plane of the sieve slit sieve and Ysieve The intersection point of the beam with the thin target foil provided a point target to within the spectrometer resolution The following positions and distances were then surveyed The results from these surveys were used to calculate the z the target position the spectrometer central angle defined to be the angle between the geo metric center axis of the dipole and the ideal beam line the displacement of the spectrometer dipole axis from the hall center the position of the sieve slit center with respect to the spectrometer central axis the position of the beam position monitors with respect to
15. ization Fig 3 In the example shown in Fig there is a clear correlation between Emiss and Orot 4 Use a polygon cut in Emiss vs rot to select events for the Emiss peak for optimization 5 Analyze again with the starting database using ana_emiss kumac Make sure that you have the calibrate optimize emiss emiss_cut line turned on in the kumac file 6 At the end of espace analyzing you would get a file named fort 52 contain ing the input data for the optimization code You should rename this file into something like emiss dat 18 10 11 Before running the optimization code edit the input file opt emiss dat See appendix Edit the vary codes in the start up database to select the matrix elements you want to optimize Please see the description of the optics database given in section 2 1 Note that in this case you have only one peak to optimize so you can restrict only a few matrix elements Therefore open up only those terms that absolutely needs optimization In the case of the example shown I opened up only D1000 and D2000 terms for the electron spectrometer Run the optimization by typing optimize emiss After some time you should get the optimized database Do a diff between old and new databases to make sure that the changes are what you expected 16 16 14 14 12 12 10 10 ped dee pe a Se fel ae 2 pode pele a jazi 0 02 0 0 02 0 04 iN opm
16. l raw number When you run cuts_xxx_l kumac for each target foil i a file named i holes dat is written this file contains the required peak information just cut and paste these files in to the input file Case of opt_dpk dat N4 lines containing the following information for each peak magnetic field of the spectrometer BO in kG mass of the target nuclei in MeV Energy loss before scattering energy loss after scattering 21 A 2 Emiss opt emiss dat is similar to what is described above except for that e arm and zoffset are not in it The peak lines in opt_emiss dat should give location of the Emiss peak MeV BO for HRS 1 in kG BO for HRS 2 in kG mass of the target nucleus in MeV mass of the recoiling nucleus in MeV 22 References Jefferson Lab Hall A ESPACE users guide available at http hallaweb jlab org espace docs html E A J M Offerman Ph D thesis 1988 F Garibaldi et al Nucl Instrum Methods A314 1 1992 M Liang Survey Summary Report http www cebaf gov Hall A publications technotes html survey _summary ps gz E A J M Offerman et al The Hall A sextupole crisis an evaluation of the magnitude of the problem and possible solutions 1995 23
17. n subroutines The subroutines write_y f and write_angle f are called by the paw kumacs Files for running espace Please refer to the espace manual for the files you need to run espace 15 sub directory for hbook files The kumac files assume a sub directory called hbook in your working directory for hbook files Input files for optimization These files are labeled opt_xxx dat for optimizations and test dat for testing the database The files for single arm optimizations xxx off ytg or ang and test dat have the same format The line items in this file are described in the appendix Change these files with the values for your setup before you start If you are only doing a visual test see below you only need to update test dat 4 2 Testing a database There are two levels of testing available to check the quality of the database 1 Visual inspection of peak positions compared to the grids of surveyed positions This requires running the optimize code only once 2 Quantitative comparison of the average reconstructed variable for each peak to the surveyed value of that variable for that peak This test re quires running the optimize code for each set of reconstructed variables separately 4 2 1 Visual test 1 In case you are using data from an elastic delta scan filter the events from the elastic peak at each momentum setting into a new set of data files and use this filtered data for your optimization 2 Use
18. pare_xxx For each peak you have selected this file will compare the surveyed value xx_0 to the average value xx_av of the reconstructed variables here xx stands for y ph and th The final column of this file will give the y computed for this peak at the moment this is not the reduced x Execute test_xxx_1 kumac in paw to generate plots Optics optimization 1 Follow steps 1 5 of the quantitative test Change the vary codes of the optics matrix elements you wish to optimize See the description of the database optics matrix line given in page 8 A vary code vc selection where vetj tk l 6 29 allows the optimization of optics matrix elements to the 6t order Make sure that the vary codes of all matrix elements of both spectrometers that you are not optimizing are set to zero Run optimize with arg1 xxx arg2 optimize optimize will print the following information onto the screen e A list of peaks it is using for optimization with corresponding z_react y sieve and x_sieve values Current optics matrix elements for both spectrometers A list of optics matrix elements it is going to optimize with step sizes and limits e Maximum number of events per peak Number of points used for optimization from each peak 17 e Other things related to optimization Make sure that this information is correct and the program is doing what you want it to do 5 After some time can be a few hours for the angle optimiz
19. re po is the rotation angle 45 VDC 2 N gt VDC 1 Q Ul gt Figure 5 Transport Coordinate System side view e Focal plane Coordinate System FCS The focal plane coordinate system chosen for the HRS analysis is a rotated coordinate system This coordinate system is obtained by rotating the DCS around its y axis by an angle p where p is the angle between the local central ray and the 2 axis of the DCS As a result the 2 axis of the FCS rotates as a function of the relative momentum 42 see Fig 6 In this rotated coordinate system the dispersive angle is small for all points across the focal plane As a result the expressions for the reconstructed vertex converge faster during optics calibrations Z ge E Za ae a oe Nh Figure 6 The focal plane rotated coordinate system as a function of the focal plane position 4The ray with 0 0 for the corresponding relative momentum ae The transformation to the FCS also includes corrections for the offsets incurred due to misalignments in the VDC package The coordinates of focal plane vertex can be written as follows Ufp Ytra 5 Yioo0 Tp 11 Lfp Xtra 12 Odet tan p btp lt 13 TP IZ baatan p 13 SS pini ec det 2 Pioog fo 14 cos p Oge sin p where tan p 5 ti000X p 15 2 1 Approach For each event two angular coordinates Age and dex and two spatial coor dinate
20. s aet and Yaet are measured at the focal plane The position of the particle and the tangent of the angle made by its trajectory along the dispersive direction are given by aet and Oaet while Ydet and qet give the position and tangent of the angle perpendicular to the dispersive direction These observ ables are used to calculate x 6 y and 6 for the particle at the target To reduce the number of unknowns at the target to four the x value was effec tively fixed at zero during the optics calibration by requiring that the beam position on target was within 250 um of the origin of the HCS The Transport Tensor links the focal plane coordinates to the target coordi nates The relationship between the focal plane and target coordinates can be written in a first order approximation as 5 ale ja 0 0 2 a _ elz ja o 0 lo ie p 0 0 ly ae p oa Lo o ly wa ll The null tensor elements result from the mid plane symmetry of the spectrom eter In practice the expansion of the focal plane coordinates is performed up to the fifth order A set of tensors Yri Tiki Pixi and Djp link the focal plane 55 25 where P is the measured momentum of a particle and Pp is the central momen tum of the spectrometer coordinates to target coordinates according to Ytg 5 Vint oY pry 17 jkl Org YT int Opn tp Pty 18 jkl beg X PinO iY ipb and 19 jkl EES ai eo jkl where the tensors Yjki Tiki Piki and Djx
21. second and the third quadrupoles Q2 and Q3 In order to ensure that normal tune of the spectrometer Q2 and Q3 have to be cycled using the prescribed procedure The matrix elements have been tested with data obtained over one year and have been shown to be stable to the accuracy l Nominal momentum ranges are Right HRS 0 4 GeV 3 0 GeV Left HRS 0 4 GeV 4 0 GeV 2When the spectrometer momentum has to be increased first raise Q2 and Q3 currents to the highest allowed values for that spectrometer 1400 Amp for Right HRS and 1600 Amp for Left HRS and then go down to the desired momentum Note that Dipoles should not be cycled quoted in section 3 0 1 Contact Doug Higinbotham at dougjlab org to obtain these matrix elements While the optics matrix elements already available will work all the experi ments within the nominal ranges of the spectrometers the focal plane detector parameters and the offsets between the actual detector coordinates and the the ideal spectrometer coordinates can change from time to time Therefore be fore the available databases are used for the analysis of an experiments these databases have to be tested for data taken during that experiment The testing procedure is described in section 2 2 Coordinate systems A detailed description of the coordinate systems used in this document is given in reference 1 For convenience a short overview is presented here All coordinate systems presented are Cartesian Note
22. the ideal beam line 0 react position for each target foil and sieve and Ysieye values for each hole center in the sieve slit 10 O o p O 36 gt Or OO lt 0 08 Os On Ox OO OO 0 06 o O O 0 0 0 0 04 O O lt O gt OOO 0 02 0 o 0000 0 0 0 02 o o O o ooo 0 04 0 06 0000 0 0 0 08 0 03 0 02 0 01 0 0 01 0 02 0 03 Figure 7 Sieve slit The large holes allow for unambiguous identification of the orientation of the image at the focal plane 3 0 1 Optics Commissioning results The following results were obtained from optics data taken at Ey 845 MeV _ _ ee Theta_tg Vs Phi_tg E Arm with a thin C target All the quantities are measured at the target e Angle determination accuracy in plane 0 2 mrad out of plane 0 6 mrad e Angular Resolution FWHM in plane 2 0 mrad out of plane 6 0 mrad e Momentum Resolution FWHM 2 5 x 1074 11 Figure 8 Reconstructed image of the sieve slit for the thin 1 C foil at Zreact 0 0 e Transverse position determination accuracy 0 3 mm e Transverse position resolution FWHM 4 0 mm 12 4 User manual for Optimize Optimize is a stand alone routine used to optimize HRS optics and scintillator database The input data for optimize is generated by ESPACE The flow chart in Figure 4 shows how Optimize works 4
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