Design of a Thomson scattering diagnostic for the SMall Aspect Ratio Tokamak (SMART)

Thomson Sca e ing diagnos ic o SMART Design o a Thomson sca e ing diagnos ic o he SMall Aspec Ra io Tokamak (SMART) M. Kau ,1A. Diallo,1B. LeBlanc,1J. Segado-Fe nandez,2E. Viezze ,2R. B. Hux o d,3A. Mancini,2D. J. C uz-Zabala,2M. Podes a,1, 4 J. W. Be ke y,1and M. Ga cia-Muñoz2 1)P ince on Plasma Physics Labo a o y, P ince on, NJ 08540, USA. 2)Depa men o A omic, Molecula and Nuclea Physics, Uni e si y o Se ille, Se ille, Spain. 3)RBH Op ics, Bu gess Hill, Wes Sussex RH15 8HL, Uni ed Kingdom 4)P esen ly a Ecole Poly echnique Fédé ale de Lausanne, Swiss Plasma Cen e , CH-1015 Lausanne, Swi ze land. (*Elec onic mail: [email p o ec ed]) We desc ibe he design o a Thomson sca e ing (TS) diagnos ic o be used on he SMall Aspec Ra io Tokamak (SMART). SMART is a sphe ical okamak being commissioned in Spain ha aims o explo e posi i e iangula i y (PT) and nega i e iangula i y (NT) plasma scena ios a a low aspec a io. The SMART TS diagnos ic is designed o ope a e a high spa ial esolu ion, 6 mm sca e ing leng h in he low- ield side (LFS) and 9 mm in he high- ield side (HFS) egions, and a wide dynamic ange, elec on empe a u e om 1 eV o 1 keV and densi y om 5 ×1018 m−3 o 1 ×1020 m−3, o esol e la ge g adien s o med a he plasma edge and in he sc ape-o laye (SOL) unde di e en iangula i ies and low aspec a ios. A 2 Joule @1064 nm lase will be used ha is capable o ope a ing in he bu s mode a 1 kHz, 2 kHz, and 4 kHz o in es iga e as phenomena and a 30 Hz o s udy 1 sec (o mo e) long discha ges. The sca e ed ligh will be collec ed o e an angula ange o 60◦– 120◦ om 28 spa ial poin s in he midplane co e ing he en i e plasma wid h and he ou e midplane SOL. Each sca e ing signal will be spec ally esol ed on i e wa eleng h channels o a polych oma o o ob ain he elec on empe a u e measu emen . We will also p esen a me hod o moni o in si u lase alignmen in he co e du ing calib a ions and plasma ope a ions. I. INTRODUCTION The p oduc ion o high densi y plasmas wi hou igge - ing magne ohyd odynamic ins abili ies like Edge Localized Modes (ELMs) is an impo an equi emen o ealizing mag- ne ic con inemen usion in a okamak. Among he a - ious okamak con igu a ions, sphe ical okamaks (ST) o - e compac -con igu a ion plasmas. Mo eo e , nega i e- iangula i y (NT)-shaped okamak plasmas o e a wide ange o ad an ages such as high-ene gy con inemen , non- ELMing plasmas, and de ached-di e o s along wi h high- densi y ope a ions1,2. He e iangula i y (δ) e e s o a pa- ame e o he shape o he poloidal c oss-sec ion o he las closed lux su ace o a okamak3. To combine he bene i s o sphe ical okamaks and nega i e- iangula i y, he SMall Aspec Ra io okamak (SMART) is cu en ly being commis- sioned a he Uni e si y o Se ille in Spain ha aims o ex- plo e he physics o NT plasmas and compa e i wi h PT coun- e pa scena ios4,5. We desc ibe he design o he TS diagnos ic o SMART o measu e he spa ially and empo ally esol ed elec on em- pe a u e (Te) and densi y (ne)6. A TS diagnos ic wo ks by accele a ing ee plasma elec ons using a linea ly-pola ized sho -pulse lase beam. Accele a ed elec ons emi elec o- magne ic adia ion. The sca e ed adia ion is called TS adi- a ion, which is collec ed and esol ed spec ally on di e en wa eleng h bands o ob ain Te om spec al b oadening and ne om he ampli ude7. Knowledge o Teand neallows one o unde s and he e ec s o a ious plasma hea ing and con- inemen echniques on okamak plasmas and he unde lying physics in di e en egimes, o example, elec on hea ans- po , pa icle anspo , e c. The p ima y goal o he TS diag- nos ic on SMART is o acili a e physics s udies by p ecisely esol ing he co e and he edge (pedes al) o bo h NT and PT con igu a ions. This diagnos ic p o ides de ailed measu e- men s ac oss he HFS and LFS egions o he magne ic axis o SMART, as well as in he co e plasma. The es o he a icle is a anged as ollows. In sec ion II, we p o ide an o e iew o SMART and b ie ly desc ibe he ope a ional equi emen o he TS diagnos ic. The design o he TS diagnos ic along wi h all i s majo componen s is gi en in sec ion III, ollowed by a summa y in sec ion IV. II. OVERVIEW SMART is designed o physics s udies by shaping plasma wi h δ anging om −0.6 o +0.6, and he aspec a io can be a ied om 1.4 o 34. The ope a ion o SMART is o eseen in h ee phases, see Table I. The o oidal magne ic ield (B ) will be a ied om 0.1 T in Phase 1 o 1 T in Phase 3, and he plasma cu en (Ip) anges om 100 kA in Phase 1 o 1 MA in Phase 3. The SMART plasmas will be hea ed in Phases 2 and 3 wi h neu al beam injec ion (NBI) o a ain high empe - a u es. Pa ame e s Phase 1 Phase 2 Phase 3 Ip[kA]100 200 −500 >500 B [T]0.1 0.4 1.0 τpulse [sec]0.15 0.5 >1 PECH [kW]6 6 200 PNBI [MW]- 0.3 - 1 1 TABLE I. Table o ope a ing pa ame e s in di e en SMART phases. He e PECH s ands o launched elec on cyclo on hea ing. Rep o- duced wi h pe mission om Podes à e al.8. CC BY 4.0. This is he au ho ’s pee e iewed, accep ed manusc ip . Howe e , he online e sion o eco d will be di e en om his e sion once i has been copyedi ed and ypese . PLEASE CITE THIS ARTICLE AS DOI: 10.1063/5.0219308 Thomson Sca e ing diagnos ic o SMART 2 Based on he ope a ional pa ame e s gi en in Table I, a li - e a u e su ey o STs is conduc ed o es ima e he Te ange o SMART plasmas in di e en phases o ope a ion. The ex- pec ed Te ange s ongly in luences he design o he diagnos- ic o a ypical densi y, ne∼1019 m−3. Fo example, he alues o Tede e mine he wa eleng h anges o he TS adia- ion ha need o be measu ed. The su ey o es ima e Teand neis summa ized in Table II. A compa ison o Table Iand II shows ha in Phase 1, SMART is expec ed o p oduce a minimum co e Teo up o 100 eV and neup o 2.5×1019 m−3based on esul s om VEST/VEST-II9–11 unde simila Ipand B anges. Globus- M12 and START13 esul s sugges co e Teand nein he ange om 300 eV o 600 eV and up o 6 ×1019 m−3, espec i ely in Phase 2 in he p esence o an ex e nal hea ing sou ce and highe Ipand B . In Phase 3, SMART is an icipa ed o achie e Teup o 1 keV and neup o 10×1019 m−3based on da a om Globus-M214–16 and ST4017. In he sc ape-o laye (SOL), Teand nemay d op o a ew eV and 0.5×1019 m−3o a lowe alue, espec i ely. The e o e, he SMART TS diagnos ic is op imized o a wide ange o expec ed SMART pa ame e s unde di e en ope a ional phases o measu e a wide Te ange om 1 eV o 1 keV and ne ange o 0.5−10 ×1019 m−3. Pa ame e s VEST/ VEST-II START Globus-M Globus-M2 ST40 Ip[kA]50−150 200 120 −250 200 − 300 350 500− 580 B [T]0.15 0.3 0.4 0.7 0.9 <1.0 Ex e nal Hea ing [MW] - 0.5 (NBI) 0.1 (RF powe ) 0.85 (NBI) 0.7 ( wo NBIs) 1.8 Te[keV]0.1 0.3 0.55 0.7− 0.9 1.5 0.9 ne[1019 m−3]2.5 6 6 8 −10 8 10 TABLE II. Table o achie ed co e Teand nein compa able STs a op- e a ing pa ame e s simila o di e en SMART phases. Please no e ha he ope a ion windows o compa able STs beyond he planned ope a ion phases o SMART a e no conside ed o compa ison. III. THE SMART TS DIAGNOSTIC The TS diagnos ic is designed o co e he i s h ee ope - a ional phases o SMART, ea u ing mul iple subsys ems ha enable he measu emen s o Teand nea a ious spa ial loca- ions and imes du ing a plasma discha ge. These subsys ems a e de ailed in his sec ion. A. High- epe i ion a e lase and beam anspo An InnoLas-made Nd:YAG lase (model SL2500) ope a - ing wi h 2 Joule nominal ene gy pe pulse a 30 Hz and pulse wid h o 10 ns a he undamen al wa eleng h o 1064 nm is pu chased. The beam di e gence and he poin ing s abili y o his lase a e 11.68 µ ad and 0.5 m ad ( ull angle), espec- i ely. This lase is capable o ope a ing in a bu s mode a educed ene gy pe pulse o achie e measu emen s a a high- epe i ion a e du ing a discha ge. He e, a bu s ep esen s a FIG. 1. He e is a schema ic o he lase beam anspo and dump. g oup o pulses (4 o 6 in ou case) i ed a a as a e. The equency o pulses in a bu s can be se a 1 kHz, 2 kHz o 4 kHz. Fo ou pulses in a bu s , he lase deli e s 1.88 J ene gy pe pulse a 4 kHz, 1.7 J a 2 kHz, and 1.57 J a 1 kHz bu s . The ene gy pe pulse d ops u he o 6 numbe o pulses in a bu s . Mo eo e , he bu s can be epea ed a e e y ∼200 ms du ing a sho . This mode will be bene icial o explo ing se - e al as phenomena and sho -pulse discha ges, o example, Phase 1 o SMART. The lase and ancilla y ins umen s will be loca ed in a oom 10 m away om he SMART es cell. A schema ic o he lase beam anspo is shown in Fig. 1. The lase is equipped wi h a ene gy me e o make measu emen s a 30 Hz ope a ions. Howe e , he as bu s pulse ene gy measu e- men s will be done a he lase head using a Cohe en ene gy me e (model Ene gyMax-USB J-50MT-10KHZ Ene gy Sen- so ) ope a ing a 10 kHz epe i ion a e. The lase beam will be expanded om 12 mm diame e o 25 mm using a Galilean beam expande o educe beam di e gence and o keep he ene gy load on o he en y window below he damage h esh- old. A e ha , a se o mi o s and lenses will ocus he e i- cally pola ized lase beam in o he midplane h ough a B ew- s e window o make Teand nemeasu emen s. Upon i s exi om he main essel, he lase beam ene gy will be measu ed, and he beam will be dumped on a Ken ek-made beam dump housed ou side he acuum essel. The lase is equipped wi h a isible alignmen lase ha will be used along wi h a came a o alignmen o he lase p io o calib a ions and ope a ions. B. TS sca e ing-loca ion selec ion and collec ion op ics The op imal measu emen loca ions and spacing be ween adjacen sca e ing poin s a e de e mined by conside ing he expec ed a ia ion in adial plasma p essu e p o iles a di - This is he au ho ’s pee e iewed, accep ed manusc ip . Howe e , he online e sion o eco d will be di e en om his e sion once i has been copyedi ed and ypese . PLEASE CITE THIS ARTICLE AS DOI: 10.1063/5.0219308 Thomson Sca e ing diagnos ic o SMART 3 FIG. 2. This image shows he loca ion o he TS measu emen ( he ed emp y ec angles) and alignmen ( he g een ec angles) poin s along he majo adius o SMART. These TS loca ions a e de e mined om he quali a i e a ia ion o he plasma p essu e along he SMART majo adius a di e en PT and NT alues. The plasma p essu e p o iles a e ob ained in ASTRA simula ions using a Gy oBohm model. e en iangula i y alues as p edic ed in ASTRA simula ion using a Gy oBohm model4. The TS measu emen loca ions and simula ion da a a e shown in Fig. 2. Please no e ha he simula ion p o iles in he NT con igu a ion a e calcula ed by unning ASTRA in p edic i e mode and using anspo coe - icien s co esponding o ST plasmas wi h PT, as no machine has e e explo ed he combina ion o NT and low aspec a io. Recen ly, mo e ad anced simula ions a e pe o med using he TRANSP code and he Mul i-Mode Model ha p o ide simi- la co e pa ame e s8,18. Simula ions sugges a na ow pedes al wid h, ∼1.2 cm, on LFS o he magne ic axis, and a sligh ly wide pedes al, ∼2 cm, on HFS due o he Sha ano shi . Addi ionally, he pedes al posi ion on LFS shi s adially wi h a change in i- angula i y; howe e , his shi is no e y p ominen on HFS. The measu emen poin s a e he e o e judiciously dis ibu ed o ensu e dense co e age in bo h he LFS and he HFS e- gions, enabling de ailed esolu ion o he edge pedes al in bo h PT and NT con igu a ions. The de ails o he TS measu emen poin s dis ibu ion in SMART is shown in Table III. Mo e han a hi d o he measu emen poin s a e dedica ed o LFS o he magne ic axis, six o he HFS pedes al, and a hi d a e uni- o mly a anged in he co e egion. Radial co e age o 52 cm is achie ed wi h 28 TS measu e- men poin s wi h a sca e ing angle (θsc) anging om 60◦ o 120◦, as shown in Fig. 3. The wide adial co e age is made possible using a cus om een an qua z iewpo ha is de- signed o b ing he collec ion op ics close o he lase line, and hence he measu emen poin s. The dis ance o he mea- su emen poin s om he collec ion op ics a ies om 50 cm o 70 cm. The clea diame e o qua z in he een an iew- po is la ge han 18 cm, enabling he use o lens elemen s Loca ion LFS HFS Co e Sca e ing leng h [mm] 5.8 9.2≤9.2 Sepa a ion be ween measu e- men poin s [mm] 7 10 35.4 No. o measu emen poin s 12 6 10 TABLE III. This able shows he dis ibu ion o TS measu emen poin s along he majo adius o SMART. He e he sca e ing leng h e e s o he ligh collec ion leng h along he lase beam ha de e - mines he sca e ed signal s eng h. Twel e measu emen poin s on LFS a e dedica ed o p o iding a spa ial esolu ion o 7 mm, and six on he HFS pedes al achie e 10 mm spa ial esolu ion. Ten measu e- men poin s a e uni o mly a anged in he co e egion o p o ide a spa ial esolu ion o 35.4 mm. wi h la ge ape u e. The e a e six elemen s in he collec ion op ics wi h hei diame e a ying om 9.2 cm ( o he i s and smalles elemen ) o 15.7 cm ( o he las and la ges el- emen ). These design conside a ions ul ima ely enable us o employ as collec ion op ics and collec a s ong ligh signal. Fu he mo e, he collec ion op ics is designed o o e a low op ical magni ica ion, M, o 2.5× o he en i e LFS measu e- men ange, as shown in Fig. 4. Low M ensu es ha he p o- jec ion o he op ical ibe on o he lase line does no exceed he desi ed sca e ing leng h o 6 mm on LFS and hence p o- ides us wi h 7 mm spa ial esolu ion (i.e., he cen e - o-cen e sepa a ion be ween adjacen measu emen poin s). The op i- cal M inc eases o 4× o he HFS pedes al and some o he co e sca e ing loca ions. This makes he sca e ing leng h o a y along he lase beam om 5.8 mm a he ou boa d edge o 9.2 mm a he inboa d edge. The collec ion op ics assembly will be housed in a da k en- closu e s a ioned ou side he acuum essel, and ligh will be collec ed om he midplane. An ach oma ic p ism is used in on o lens elemen s in he collec ion op ics o de ia e i s op- ical axis by 10◦. This p e en s he op ical pa h om clashing wi h he nea by poloidal coils. Decen e ed and il ed op ical elemen s a e used o co ec asymme ic abe a ions a ising FIG. 3. This image shows he lines o sigh o he Thomson sca e - ing diagnos ic in he mid-plane ( he op iew). The e a e 30 sca e - ing loca ions, 28 o which a e o measu ing localized plasma pa am- e e s, and wo a e dedica ed o moni o ing he lase alignmen wi h espec o he collec ion op ics. This is he au ho ’s pee e iewed, accep ed manusc ip . Howe e , he online e sion o eco d will be di e en om his e sion once i has been copyedi ed and ypese . PLEASE CITE THIS ARTICLE AS DOI: 10.1063/5.0219308 Thomson Sca e ing diagnos ic o SMART 4 FIG. 4. This image shows M (in he ed ci cles), he op ical magni- ica ion, o he collec ion op ics along he majo adius o SMART. The blue do ed line co esponds o M =2.5. om he ach oma ic p ism. Using decen ed and il ed ele- men s also a oids using a shallow cylind ical op ical su ace on he p ism, which is di icul o manu ac u e. The esul- an op ical sys em uses all con en ional sphe ical lens ele- men s, which a e bo h easie o manu ac u e and assemble, while achie ing he same op ical pe o mance as a mo e com- plica ed sys em wi h o oidal su aces. A he end o he col- lec ion op ics, a wi e g id pola ize will be ins alled o educe andomly pola ized plasma backg ound ligh and collec only he pola ized TS ligh . The collec ion op ics images he lase beams on o a con in- uous ibe bundle holde o moun ing 30 ec angula Op ical Fibe Bundles (OFB). All OFBs a e made up o low-OH pu e silica co e/polyme cladding 210/230-mic ome e diame e s wi h hei jacke s emo ed and a nume ical ape u e (NA) o 0.285. The ec angula side o each OFB has an a ea o 2.3×1.44 mm2and con ains 66 ibe s. The o he end o he OFB ha goes o he polych oma o comp ises ibe s o wo OFBs in a ci cula c oss sec ion o 3 mm diame e in a an- dom dis ibu ion. The wo legs o he composi e OFB ha e di e en leng hs, pe mi ing ime mul iplexing o he da a. Mo e de ails a e p o ided in he nex subsec ion. C. Measu emen o TS spec um om collec ed ligh Pa ame e s Ch 1 Ch 2 Ch 3 Ch 4 Ch 5 CWL (nm) 1061.1 1057.7 1047.5 1017.5 917 Bandwid h (nm) 2 5.5 15 45 155 Quan um e i- ciency (%) 36.2 38.9 44.5 62.5 87.6 TABLE IV. This able lis s CWL and bandwid h ( ull-wid h a hal - maxima) o i e in e e ence il e s moun ed on o he polych oma o s and he quan um e iciencies o he APDs a CWL. Measu ing he TS spec um in ol es eco ding he in ensi y o sca e ed ligh a di e en wa eleng hs. The wa eleng h ange ha needs o be measu ed depends on he Te ange o be measu ed. To esol e he expec ed Te ange o SMART, discussed in sec ion II, we pu chased 14 polych oma o s om UKAEA19. Each polych oma o is designed o accommoda e up o se en spec al channels (Ch), bu is cu en ly equipped wi h i e op ical in e e ence il e s. The cen al wa eleng h (CWL) and bandwid h o hese in e e ence il e s and he quan um e iciency o he a alanche pho odiodes (APD ha con e s he op ical signal in o ol ages) a CWL a e lis ed in Table IV, and he TS spec um o he expec ed Te ange is FIG. 5. The TS spec um is plo ed o di e en alues o Teand θsc. Low Te(1 - 10 eV) is expec ed in he SOL egion, whe e θsc is 60◦ in LFS o 120◦in HFS. Mode a e (100 eV) o high Te(0.5 - 1 keV) is expec ed nea he ou e plasma edge and in he co e egion, whe e θsc is 115◦in HFS (o 65◦in LFS) and 90◦, espec i ely. The al e - na e pink and yellow colo s in he backg ound ep esen he passing wa eleng h bands o i e in e e ence il e s, as de ailed in Table IV. The na ow bandwid h il e , i.e., Ch 1 o Table IV, enables low Te measu emen s. shown in Fig. 5. The TS spec um is calcula ed o he com- bina ions o Teand θsc ha a e expec ed a di e en adial loca ions, as guided by Fig. 2. Each polych oma o is equipped wi h a na ow bandwid h il e , i.e., Channel 1 o Table IV, o enables low Temea- su emen s. The addi ional wo channels on each polych o- ma o can be popula ed in he u u e o co e an ex ended Te ange. Based on he u u e SMART da a and physics o in- e es , he co e polych oma o channels can be popula ed wi h lowe wa eleng h il e s o measu e Tehighe han 1 keV and edge channels wi h highe wa eleng h il e s o imp o e he low Teand ne ange measu emen s. To op imize he use o polych oma o s, each polych oma- o will collec a sca e ed ligh signal om wo sca e ing lo- ca ions in he mid-plane using an unequal leng h bi u ca ed OFB. The leng h o wo bi u ca ed bundle legs is 12 m and 22 m. The leng h di e ence is kep as 10 m o in oduce a ime sepa a ion o 48 ns be ween he signals om wo sca - e ing loca ions. This scheme enables 14 polych oma o s o p o ide in o ma ion on plasma pa ame e s om 28 di e en adial loca ions, and hence o e s be e spa ial esolu ion and co e age han ha p o ided by 14 adial loca ions. Ro a ional Raman calib a ion will be used o de e mine he sensi i i y o he ligh signal om di e en sca e ing loca ions in he mid- plane ha will be used in densi y de e mina ion20. Because o he sensi i e na u e o he calib a ion on he lase alignmen and he possibili y o qua z window deg ada ion o e ime due o coa ing, he calib a ion will be pe o med bo h du ing he ins alla ion o he TS sys em and a he s a o e e y majo SMART campaign. D. Lase alignmen moni o ing We de eloped a no el se up o ac i ely moni o in si u lase alignmen du ing each sho such ha co ec i e ac ions can be aken in be ween sho s i any misalignmen occu s. In his se up, wo sca e ing loca ions in he co e, indica ed in he g een colo in Fig. 2, a e dedica ed o moni o ing This is he au ho ’s pee e iewed, accep ed manusc ip . Howe e , he online e sion o eco d will be di e en om his e sion once i has been copyedi ed and ypese . PLEASE CITE THIS ARTICLE AS DOI: 10.1063/5.0219308 Thomson Sca e ing diagnos ic o SMART 5 FIG. 6. This image shows a quad-OFB ha is used wi h a one- channel polych oma o o moni o ing lase alignmen wi h espec o he collec ion op ics. The quad-OFB has ou unequal-leng h OFB legs o in oduce a ime delay be ween he signals om di e en poin s. lase alignmen using a quad-OFB and a one-channel poly- ch oma o . The quad-OFB has ou unequal-leng h legs, as shown in Fig. 6, o in oduce ime delay be ween signals om ou legs. Each sca e ing loca ion is co e ed by wo legs o he quad-OFB a anged e ically in a ec angle, o a ea 1.44 mm×2.3 mm, such ha one bundle collec s a ligh signal om he op hal o he lase line, whe eas he second collec s ligh om he bo om hal . The one-channel polych oma o is pu chased along wi h he o he 14 polych oma o s. I is equipped wi h one in e e - ence il e wi h a passing wa eleng h band o 1040−1055 nm (i.e., Channel 3 o Table IV). The adial posi ion o he align- men ibe s and passing wa eleng h band o he in e e ence il e a e selec ed such ha he wo measu emen poin s a e a hes apa in he co e and ga he a s ong signal du ing Raman calib a ions and day- o-day ope a ions while ensu ing leas con ibu ion om Rayleigh ligh . Using he same poly- ch oma o on all he OFB legs ensu es ha he ou posi ions ( adial and e ical) eco d equal signal s eng h o a pe ec ly aligned lase beam wi h espec o he collec ion op ics. IV. SUMMARY We desc ibed he design o a mul ipulse Thomson sca e - ing sys em o measu e he elec on empe a u e and densi y p o iles in he mid-plane o SMART. Special emphasis was laid on measu ing he pedes al egion on LFS and HFS o he magne ic axis wi h a high spa ial esolu ion o compa e PT and NT plasma scena ios. The diagnos ic will ope a e wi h (i) a high spa ial esolu ion o 7 mm (sepa a ion be ween 12 adjacen poin s) in he LFS pedes al egion and 10 mm in he HFS egion, and (ii) a wide dynamic ange, 1 eV o 1 keV, o esol e la ge g adien s o med a he plasma edge and in SOL unde di e en iangula i y condi ions and low aspec a ios. A as collec ion op ics enables e icien use o he ou een polych oma o s a ailable o collec he plasma in o ma ion a 28 spa ial loca ions co e ing he en i e plasma wid h along wi h he ou e midplane SOL. In addi ion, he collec ion op- ics o e a low M in he LFS egion, allowing igh spacing be ween measu emen poin s and a high spa ial esolu ion, as men ioned abo e. A no el se up is de eloped o moni o in si u lase alignmen using a polych oma o equipped wi h one in e e ence il e and a quad-OFB a wo sca e ing loca ions in he co e du ing Raman calib a ions and day- o-day ope a- ions. The design and o de o mos majo pa s o he SMART TS diagnos ic (lase , polych oma o s, collec ion op ics, ibe bundles, da a acquisi ion, e c.) a e comple e. ACKNOWLEDGMENTS This wo k was p ima ily suppo ed by he U.S. Dep . o En- e gy, O ice o Fusion Ene gy Sciences unde con ac num- be DE-AC02-09CH11466. A pa o he wo k is ca ied ou wi hin he EURO usion Conso ium amewo k, pa ially unded by he EU ia he Eu a om Resea ch and T aining P o- g am (G an Ag eemen No 101052200 — EURO usion). The Swiss con ibu ion o his wo k has been unded by he Swiss S a e Sec e a ia o Educa ion, Resea ch and Inno a ion. DATA AVAILABILITY STATEMENT The da a ha suppo he indings o his s udy a e a ailable om he co esponding au ho upon easonable eques . 1Y. Camenen, A. Pochelon, R. Behn, A. Bo ino, A. 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