8th	  Photon	  Factory	  Science	  Advisory	  Commi6ee	  Mee8ng	  March	  29-­‐30,	  2016	  Execu8ve	  Summary	  and	  Close-­‐Out	  Remarks	  SAC	  Commi6ee	  Members:	  	  Michael	  Borland	  (Advanced	  Photon	  Source,	  Argonne	  Na9onal	  Laboratory)	  	  John	  Hill	  (NSLS-­‐II,	  Brookhaven	  Na9onal	  Laboratory)	  Mitsuhiro	  Hirai	  (Gunma	  University)	  Yasuhiro	  Iwasawa	  (University	  of	  Electro-­‐Communica9ons	  Tokyo)	  Ingolf	  Lindau	  (Stanford	  University)	  Chair	  Mamoru	  Sato	  (Yokohama	  City	  University)	  Masashi	  Takigawa	  (ISSP,	  The	  University	  of	  Tokyo)	  Zhentang	  Zhao	  (Shanghai	  Synchrotron	  Radia9on	  Facility)	  absent	  but	  provided	  wriQen	  input	  07	  October	  2011	  	  1	  The	  Director	  of	  the	  Photon	  Factory,	  Murakami-­‐san,	  charged	  the	  SAC	  to	  address	  a	  number	  of	  ques8ons.	  
1.	  How	  does	  the	  PF-­‐SAC	  evaluate	  the	  present	  status	  of	  the	  PF?	  
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PF	  remains	  a	  highly	  produc9ve	  facility	  suppor9ng	  many	  users.	  It	  should	  be	  very	  proud	  of	  its	  history	  and	  its	  accomplishments.	  
The	  erosion	  in	  the	  budget	  over	  the	  last	  several	  years	  directly	  threatens	  the	  health	  of	  the	  facility	  and	  the	  produc9vity	  of	  beamlines.	  
The	  performance	  of	  the	  facility	  is	  now	  well	  past	  being	  state-­‐of-­‐the-­‐art	  and	  no	  longer	  addresses	  the	  needs	  of	  the	  most	  demanding	  research.	  It	  is	  important	  that	  it	  be	  replaced	  with	  a	  state-­‐of-­‐the	  art	  light	  source	  as	  soon	  as	  possible.	  The	  PF-­‐SAC	  recommends	  that	  KEK	  makes	  the	  KEK-­‐LS	  its	  very	  highest	  priority	  in	  the	  coming	  years.	  
It	  would	  be	  best	  for	  the	  Photon	  Factory	  if	  it	  could	  con9nue	  to	  run	  as	  long	  as	  possible,	  and	  with	  the	  maximum	  possible	  user	  hours,	  while	  eﬀec9vely	  serving	  the	  needs	  of	  those	  users.	  
In	  case	  the	  KEK-­‐LS	  is	  approved	  it	  is	  important	  to	  carefully	  think	  through	  the	  transi9on	  to	  closing	  the	  PF.	  This	  will	  require	  balancing	  the	  produc9vity	  of	  exis9ng	  beamlines	  (that	  are	  facing	  declining	  resources)	  against	  the	  needs	  for	  staﬀ	  to	  move	  from	  PF	  to	  KEK-­‐LS	  to	  design	  and	  construct	  the	  new	  beamlines.	  Early	  accommoda9on	  of	  exis9ng	  users	  at	  other	  facili9es	  will	  ease	  this	  transi9on.	  

06	  April	  2016	  	  2	  1a.	  Does	  the	  PF-­‐SAC	  have	  any	  advice	  on	  how	  to	  take	  measures	  against	  the	  poor	  ﬁnancial	  condi9on?	  
The	  SAC	  is	  well	  aware	  that	  the	  PF	  management	  has	  taken	  a	  number	  of	  construc9ve	  ac9ons	  in	  the	  past	  to	   mi9gate	   the	   declining	   opera9on	   budget.	   The	   present	   SAC	   came	   up	   with	   a	   number	   of	   routes	   to	  respond	  to	  the	  ﬁnancial	  situa9on:	  	  • Consider	  ge_ng	  user	  organiza9ons	  from	  across	  Japan	  to	  write	  leQers	  of	  support.	  	  	  • Concentrate	  eﬀort	  on	  the	  most	  produc9ve,	  high-­‐impact	  beamlines:	  Further	  consolida9on	  of	  which	  beamlines	  are	  operated	  by	  the	  facility.	  
Further	  classiﬁca9on	  of	  proposals,	  with	  concentrated	  user	  support	  for	  the	  most	  highly-­‐rated	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  proposals.	  
• Ac9vely	  aQempt	  to	  increase	  partnerships	  in	  the	  facility:	  Explore	  new	  beamline	  partnerships	  with	  university	  and	  industry,	  also	  with	  other	  countries	  that	  might	  be	  interested	  in	  developing	  SR	  exper9se	  (e.g.	  Africa)	  –	  PF	  has	  a	  successful	  track	  record	  with	  Australia	  and	  India.	  
Consider	  changing	  the	  deal;	  (50	  %	  General	  Users)	  to	  encourage	  new	  partnerships	  on	  beamlines.	  
For	   beamlines	   that	   are	   not	   a	   priority	   for	   PF,	   PF	   could	   oﬀer	   that	   the	   partners	   get	   75%	   of	   the	   9me,	  for	  example.	  
Consider	  moving	  away	  from	  the	  model	  of	  a	  partnership	  in	  a	  single	  beamline.	  For	  example:	  would	  an	  industrial	  consor9um	  consider	  paying	  a	  frac9on	  of	  the	  power	  bill	  in	  return	  for	  access	  to	  a	  suite	  of	  beamlines	  rather	  than	  just	  one?	  
06	  April	  2016	  	  3	  2.	  Are	  we	  moving	  in	  the	  right	  direc9on	  by	  changing	  the	  PF	  future	  plans?	  	  	  	  	  	  	  	  The	  plans	  are	  proposed	  as	  follows:	  	  	  •	  	  •	  	  •the	  3	  GeV	  ERL	  project	  is	  stopped	  and	  the	  3	  GeV	  SR	  LS	  project	  as	  a	  short	  and	  middle-­‐term	  plan	  and	  a	  linac	  based	  LS	  project	  as	  a	  long-­‐term	  plan	  is	  started	  The	  commiQee	  supports	  the	  decision	  to	  stop	  work	  on	  the	  ERL	  design/construc9on	  and	  develop	  a	  state-­‐of-­‐the-­‐art	  3	  GeV	  storage	  ring	  light	  source	  based	  on	  the	  following	  considera9ons:	  	  1. ERL	  technology	  is	  not	  ready	  to	  support	  construc9on	  of	  a	  new	  3	  GeV	  LS.	  
2. The	  Hybrid	  MBA	  (Mul9	  Band	  Achromat)	  la_ce	  gives	  the	  near-­‐term	  op9on	  to	  build	  a	  new	  3	  GeV	  LS.	  It	  gives	  equal	  or	  beQer	  brightness	  than	  a	  future	  ERL,	  higher	  ﬂux	  than	  an	  ERL,	  and	  has	  fewer	   technical	   challenges	   than	   an	   ERL.	   The	   MBA	   concept	   has	   been	   studied	   in	   detail	   and	  recently	  shown	  to	  work	  at	  the	  MAX-­‐IV	  3	  GeV	  storage	  ring.	  
KEK-­‐LS	   based	   on	   3	   GeV	   MBA	   la_ce	   will	   enable	   the	   explora9on	   of	   structure	   and	   dynamics	   over	  unprecedented	  length	  and	  9me	  scales,	  enabling	  advances	  in	  materials	  science,	  life	  science,	  energy	  sciences	  and	  beyond.	  It	  would	  put	  KEK	  in	  a	  world-­‐leading	  posi9on	  and	  should	  be	  pursued	  with	  the	  very	  highest	  priority	  within	  KEK.	  
The	   commiQee	   also	   supports	   the	   long-­‐term	   plan	   to	   develop	   a	   linac-­‐based	   source,	   speciﬁcally,	   a	   CW	  FEL.	  

06	  April	  2016	  	  4	  3.	  How	  does	  the	  PF-­‐SAC	  evaluate	  the	  KEK	  Light	  Source?	  	  3.1	  A.	  Is	  the	  design	  cu_ng-­‐edge	  enough?	  
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A	  good	  deal	  of	  careful	  work	  and	  thought	  has	  been	  given	  to	  the	  design.	  It	  follows	  the	  design	  of	  ESRF	  with	  some	  interes9ng	  varia9ons,	  such	  as	  short	  interior	  straight	  sec9ons.	  
A	  bolder	  design	  should	  be	  considered	  to	  “future	  proof”	  the	  new	  LS:	  1. Increase	   the	   circumference	   and/or	   number	   of	   cells	   so	   that	   few	   (or	   none)	   of	   exis9ng	   3	   GeV	   LS	  can	  easily	  surpass	  your	  planned	  performance;	  2. Consider	  a	  9BA	  design,	  which	  may	  give	  a	  factor	  of	  2	  reduc9on	  in	  emiQance;	  3. Consider	  reverse	  bending	  magnets,	  which	  may	  give	  another	  factor	  of	  two.	  
A	  series	  of	  design	  op9ons	  should	  be	  created,	  from	  “easy”	  to	  extremely	  challenging,	  and	  a	  decision	  made	  based	  on	  risk	  and	  performance.	  The	  future	  users	  should	  be	  engaged	  early	  in	  discussions	  of	  this	  trade-­‐oﬀ.	  

06	  April	  2016	  	  5	  3.1	  B.	  Are	  the	  future	  development	  items	  adequate?	  
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AQen9on	   should	   be	   given	   soon	   to	   vacuum	   design,	   impedance,	   and	   collec9ve	   instabili9es,	   which	  may	  have	  unexpected	  eﬀects	  on,	  e.g.,	  beam	  accumula9on.	  
Collabora9ons	   should	   be	   formed	   with	   other	   labs	   (e.g.,	   MAX-­‐IV,	   SIRIUS,	   APS),	   that	   have	   or	   are	  pursuing	  advanced	  vacuum	  system	  designs.	  
Ground	   mo9on	   will	   aﬀect	   not	   only	   the	   accelerator,	   but	   also	   the	   beamlines.	   Considera9on	   of	  beamline	  stabiliza9on	  should	  not	  be	  neglected.	  
In	   addi9on	   to	   robust	   mechanical	   design,	   advanced	   photon	   BPMs	   will	   signiﬁcantly	   improve	   beam	  stability.	  
At	   present,	   it	   seems	   the	   need	   for	   large	   dynamic	   apertures	   is	   in	   part	   driven	   by	   the	   large	   eﬀec9ve	  linac	  emiQance.	  This	  may	  unnecessarily	  restrict	  considera9on	  of	  more	  challenging	  la_ces.	  
Understand	   user	   requirements	   for	   9ming	   studies	   and	   how	   these	   may	   impact	   accelerator	   design,	  life9me,	  etc.	  
Use	  tracking-­‐based	  mul9-­‐objec9ve	  algorithms	  to	  op9mize	  nonlinear	  dynamics.	  
Considerable	   9me	   on	   a	   mid-­‐sized	   compu9ng	   cluster	   will	   be	   needed	   for	   this	   and	   other	   beam	  	  	  dynamics	  work.	  
Explore	  use	  of	  a	  lower-­‐frequency	  rf	  system	  (e.g.,	  MAX-­‐IV)	  combined	  with	  a	  higher	  harmonic	  cavity	  to	  improve	  life9me,	  ﬁll	  paQerns,	  and	  top-­‐up	  interval	  and	  how	  this	  will	  impact	  experiments.	  
Ensure	   that	   the	   impact	   of	   planned	   IDs	   on	   beam	   dynamics	   and	   emiQance	   is	   thoroughly	   understood,	  including	  varia9on	  of	  emiQance	  as	  gaps	  change.	  

06	  April	  2016	  	  6	  3.1	  C.	  Should	  we	  organize	  the	  machine	  advisory	  commiQee	  to	  get	  more	  detailed	  technical	  sugges9ons?	  
The	  SAC	  strongly	  recommends	  the	  forma9on	  of	  a	  machine	  advisory	  commiQee	  (MAC).	  There	  are	  two	  compelling	  reasons	  for	  this:	  1. There	   is	   a	   great	   deal	   of	   work	   on	   this	   topic	   world-­‐wide	   and	   KEK	   can	   beneﬁt	   from	   tapping	   into	  ideas	  and	  feedback	  from	  other	  laboratories.	  
2. A	  MAC	  will	  help	  increase	  the	  visibility	  of	  KEK	  work	  and	  staﬀ	  at	  other	  facili9es.	  

3.2	  About	  science,	  op9cs,	  beamlines,	  opera9ons,	  etc.	  
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A	   good	   science	   case	   was	   presented,	   but	   it	   is	   understandably	   fairly	   generic	   at	   this	   point	   in	   9me.	   KEK	  should	  develop	  a	  few	  (5)	  speciﬁc	  high	  impact	  science	  examples	  made	  possible	  by	  KEK-­‐LS.	  
Op9cs	  calcula9ons	  should	  be	  done	  using	  wavefront	  propaga9on	  and	  realis9c	  slope	  errors	  as	  soon	  as	   possible	   to	   provide	   users	   with	   an	   understanding	   of	   actual	   performance,	   and	   to	   inform	   the	  machine	  design	  (e.g.,	  round	  versus	  ﬂat	  beams).	  
Data	  management	  (acquisi9on,	  analysis	  and	  storage)	  will	  be	  a	  big	  issue	  at	  this	  new	  facility.	  Careful	  considera9on	  of	  the	  requirements	  early	  on	  will	  be	  important	  in	  the	  long	  term	  success	  of	  the	  facility.	  
An	  eﬀort	  should	  be	  made	  to	  understand	  the	  detector	  requirements	  driven	  by	  the	  new	  facility	  and	  to	  fund	  appropriate	  R&D	  to	  meet	  these	  requirements.	  
Next	  genera9on	  beamlines	  feature	  large	  end-­‐sta9ons	  and	  frequently	  go	  outside	  the	  experimental	  hall.	  This	  should	  be	  a	  design	  considera9on	  from	  the	  start.	  
06	  April	  2016	  	  7	  3.3	  Can	  the	  KEK	  light	  source	  be	  the	  facility	  which	  leads	  the	  way	  in	  the	  growth	  and	  development	  of	  synchrotron	  radia9on	  research	  in	  the	  world	  for	  the	  next	  two	  decades	  and	  coun9ng?	  
••Poten9ally	   yes.	   To	   convince	   the	   value	   of	   the	   KEK	   light	   source	   for	   society,	   the	   SAC	   urges	   the	  management	  to	  propose	  several	  cri9cal	  problems	  that	  can	  be	  solved	  by	  the	  new	  light	  source	  and	  bring	  large	  impact	  to	  the	  human	  life.	  
The	   SAC	   further	   proposes	   to	   organize	   workshops	   joined	   by	   people	   among	   diﬀerent	   ﬁelds	   and	  exper9se	   to	   deﬁne	   the	   science	   to	   be	   pursued.	   In	   so	   doing	   include	   poten9al	   users	   from	   beyond	  exis9ng	   PF	   community.	   Use	   that	   informa9on	   to	   jus9fy	   the	   speciﬁca9ons	   of	   the	   3	   GeV	   ring	   and	  beamlines.	  

3.4	  Does	  the	  PF-­‐SAC	  have	  any	  advice	  on	  how	  to	  launch	  the	  plan	  formula9ng	  a	  coopera9ve	  framework	  in	  Japan?	  
••The	  SAC	  is	  of	  the	  ﬁrm	  opinion	  that	  the	  new	  3	  GeV	  ring	  should	  be	  built	  based	  on	  the	  state-­‐of-­‐the-­‐art	  technology	  available	  today,	  so	  that	  it	  can	  serve	  as	  the	  plasorm	  to	  advance	  the	  fron9er	  of	  science	  for	  the	  next	  twenty	  years,	  including	  the	  research	  in	  industries.	  
Considering	  that	  this	  probably	  will	  be	  the	  only	  	  3rd	  genera9on	  medium-­‐energy	  	  X-­‐ray	  light	  source	  in	  Japan,	   the	   plan	   for	   the	   ring,	   beamlines	   and	   instruments,	   as	   well	   as	   the	   opera9on	   of	   the	   facility	  should	   be	   discussed	   and	   agreed	   by	   the	   na9on-­‐wide	   synchrotron	   community	   including	   academic,	  government	  and	  industrial	  users.	  
06	  April	  2016	  	  8	  4.	  The	  long-­‐term	  future	  plan	  4.1	  Does	  the	  PF-­‐SAC	  support	  the	  direc9on	  to	  promote	  the	  linac-­‐based	  light	  source	  as	  a	  long-­‐term	  future	  plan?	  
••Yes,	  speciﬁcally,	  the	  commiQee	  supports	  development	  of	  a	  plan	  for	  a	  future	  linac-­‐based	  CW	  FEL	  for	  two	   reasons:	   	   Beyond	   MBA	   storage	   rings,	   there	   is	   no	   other	   technology	   that	   promises	   such	   a	  drama9c	  improvement	  in	  light	  source	  characteris9cs.	   	  Unlike	  an	  ERL,	  extremely	  high	  performance	  does	  not	  require	  high	  average	  current.	  
All	   exis9ng	   facili9es	   are	   based	   on	   pulsed	   opera9on,	   so	   pursuing	   CW	   opera9on	   provides	   a	   clear	  compe99ve	  advantage.	  KEK	  is	  in	  an	  excellent	  posi9on	  to	  pursue	  a	  project	  of	  this	  kind.	  

4.2	  Does	  the	  PF-­‐SAC	  have	  sugges9ons	  for	  the	  R&D	  projects	  of	  the	  linac-­‐based	  light	  source?	  
••••Superconduc9ng	   rf	   technology	   targe9ng	   reduced	   opera9ng	   costs,	   e.g.,	   high-­‐Q	   developments	   and	  high-­‐temperature	  opera9on.	  
Gun	  technology	  for	  CW	  high-­‐brightness	  beams.	  
Form	   or	   strengthen	   collabora9ons	   with	   facili9es	   oﬀering	   best-­‐in-­‐class	   technologies	   to	   minimize	  R&D	  eﬀort	  and	  risk.	  
Contribu9ng	  to	  world-­‐wide	  developments	  will	  prepare	  KEK	  to	  develop	  a	  solid	  design	  when	  needed.	  

06	  April	  2016	  	  9	  SAC	  Other	  Remarks	  and	  Comments	  The	   SAC	   very	   much	   appreciated	   the	   presenta9on	   by	   Yamada-­‐san	   on	   the	   organiza9on	   and	   mission	   of	   the	   Ins9tute	   of	  Materials	  Structure	  Science	  (IMSS).	  Okada-­‐san	  gave	  an	  extensive	  review	  and	  status	  report	  on	  the	  ac9vi9es	  at	  KEK	  that	  provided	   most	   valuable	   to	   provide	   the	   SAC	   with	   an	   understanding	   of	   the	   Photon	   Factory	   in	   a	   broader	   context.	   The	  Director	   of	   the	   Photon	   Factory,	   Murakami-­‐san,	   presented	   an	   in-­‐depth	   descrip9on	   of	   the	   status	   of	   the	   facility	   and	  background	   material	   for	   the	   proposed	   future	   direc9on.	   Murakami-­‐san	   also	   gave	   the	   charge	   to	   the	   commiQee	   in	   a	  number	  of	  ques9ons	  addressed	  in	  this	  report.	  	  The	   KEK-­‐LS	   project	   was	   presented	   in	   a	   series	   of	   talks	   by	   Nakao-­‐san,	   Harada-­‐san,	   Amemiya-­‐san	   and	   Adachi-­‐san	   covering	  the	  science	  case,	  the	  accelerator,	  beamlines	  and	  organiza9on	  &	  opera9on,	  respec9vely.	  The	  plans	  for	  the	  future	  linac-­‐based	   light	   source	   were	   given	   by	   Umemori-­‐san	   and	   Adachi-­‐san.	   These	   excellent	   talks	   were	   the	   backbone	   for	   the	   SAC	   in	  addressing	  the	  charge	  to	  the	  commiQee.	  	  The	  SAC	  was	  very	  impressed	  by	  the	  well-­‐prepared	  presenta9ons	  and	  appreciated	  the	  frank	  and	  open	  discussions	  on	  the	  most	   crucial	   issues.	   Last,	   but	   not	   least,	   the	   SAC	   thanks	   the	   Photon	   Factory	   management	   and	   staﬀ	   for	   their	   excellent	  logis9cal	  arrangements	  and	  support	  in	  prepara9on	  of	  the	  mee9ng.	  The	  great	  hospitality	  throughout	  the	  mee9ng	  was	  very	  much	  appreciated.	  	  In	  concluding,	  the	  SAC	  notes	  that	  the	  Photon	  Factory	  has	  a	  long	  and	  dis9nguished	  history	  of	  leadership	  and	  produc9vity	  in	  accelerator	  technology	  and	  photon	  science.	  The	  SAC	  is	  convinced	  that	  PF’s	  new	  direc9on	  is	  the	  right	  one	  and	  eagerly	  looks	  forward	  to	  seeing	  a	  world-­‐leading	  light	  source	  created	  at	  KEK.	  Given	  the	  compe99ve	  nature	  of	  the	  ﬁeld	  and	  the	  world-­‐leading	  opportunity	  available	  at	  KEK,	  the	  SAC	  strongly	  feels	  that	  KEK-­‐LS	  should	  be	  KEK’s	  highest	  priority.	  	  Stanford,	  April	  7,	  2016.	  	  	  	  	  	  Ingolf	  Lindau	  (Chair,	  on	  behalf	  of	  the	  SAC)	  07	  April	  2016	  	  10