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Evolution of the Detector Module Design for CORELLI at SNS

Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

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Page 1: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

Evolution of the Detector Module Design for CORELLI at SNS

Page 2: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

2 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Outline of Talk

•  Introduc)on  to  Corelli  and  Corelli  Detectors  • Why  the  Need  for  a  Different  Detector  Design  • Design  Challenges  • Working  Solu)ons  •  Final  Comments  

Page 3: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

3 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

What is CORELLI? aka Elastic Diffuse Scattering Spectrometer (managed as part of the SING II project)

Corelli  is  a  sta)s)cal  chopper  spectrometer  designed  and  op)mized  to  probe  local  disorder  through  diffuse  sca@ering  from  single  crystals    It  combines  the  high  efficiency  of  white  beam  Laue  diffrac)on  with  energy  discrimina)on  by  modula)ng  the  beam  with  a  sta)s)cal  ‘correla)on’  chopper    Corelli  will  be  the  first  instrument  in  the  world  dedicated  to  the  study  of  diffuse  sca@ering  with  energy  discrimina)on  

Page 4: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

4 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

CORELLI is located on BL9 at SNS

Corelli  BL9  

Proton  Beam  Direc2on    

Bridge  to  CLO  

Page 5: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

5 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Instrument Layout

20 m

2.5 m

Moderator C/L Sample C/L Detector C/L

Choppers

Sample Scattering Vessel

Page 6: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

6 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Detector Array

•  3  rows  of  He-­‐3  Filled  Linear  Posi)on  Sensi)ve  Detectors  (GE  Reuter-­‐Stokes)  •  1.27  cm  diameter  x  83.9  cm  ac)ve  length,    Spa)al  Resolu)on  ≈  1  cm  x  1  cm  •  16  tubes  per  module,  30  modules  per  row  for  a  total  of  1440  tubes  •  Ver)cal  Range            -­‐  28.5o    to    +  28.5o  •  Horizontal  Range    -­‐  23o    to    +  152o  

•  Ini)al  phase  to  consist  of  38  modules,  mostly  located  along  middle  row    

Sample Scattering Vessel Detector Array Frame

Page 7: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

7 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

No Isolation Valve for Corelli …

• No  room  to  fit  valve  to  isolate  sample  vacuum  space  from  detector  vacuum  space  

•  Thus,  we  need  to  vent  and  pump  en2re  vacuum  vessel  with  each  sample  change  

Page 8: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

8 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

... Resulting in a Few Design Challenges Compared with the ‘ARCS’ detector 1.          To  reduce  pump  down  )me,  

detector  electronics  need  to  be  placed  inside  compartment  which  is  separate  from  the  vacuum  space  

 

                         ARCS  design  open  to    vacuum  

2.          15  Wa@s  per  module    

                         twice  that  of  ARCS  8-­‐pack  design    

3.          Electronic  circuit  board  designs  (preamplifiers  in  par)cular)  require  temperatures  to  be  stable  to  within  1-­‐2  oC  for  reliable  performance  

 

                         same  as  for  ARCS  but  harder                                    to  achieve  for  Corelli  due  to                                periodic  vent/vacuum  cycles        ARCS  8-­‐pack  detector  module      

2.54  cm  dia.  x  100  cm  long  tubes  

Page 9: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

9 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Design Challenge #1 Met

Electronics  Tray  Fits  in  Compartment  Behind  

Detector  Tubes  

Detector  Electronics  Tray  Assembly  

Page 10: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

10 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Design Challenge #2 (15 Watts of Power) Two Options Considered:

•  Ac)ve  Cooling          (forced  air  flow  through    electronics  compartment)  

         •  Passive  Cooling  via  heat  sinks  and  black  surfaces  

Cooling  Lines  

Painted  Black  Inside  and  Out  

Page 11: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

11 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Thermal Imaging Identified ‘Hot Spots’ for Placement of Heat Sinks

Page 12: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

12 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Custom Vacuum Chamber Built to Simulate Vent/Vacuum Cycles in Lab •  Atm  to  <1E-­‐4  Torr  in  30  min  

•  Cooling  lines  connected  to  house  air  (and  flow  controllers)  

•  Circuit  boards  have  built  in  thermal  sensors  

•  Also  used  TC  gauges  to  measure  surface  temperatures  

•  Power  and  signal  cables  to  quan)fy  stability  of  detector  electronics  

Page 13: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

13 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Design Challenge #2 Met

• We  targeted  <  60  oC  to  be  consistent  with  ARCS  design  

•  Able  to  adequately  cool  with  reasonable  air  flow  (0.5  CFM)  

•  Also  able  to  passively  cool  with  black  surfaces,  modest  reposi)oning    of  boards,  and  applica)on  of  heat  sinks  

0  

10  

20  

30  

40  

50  

60  

0   20   40   60   80   100   120  

Tempe

rature    oC  

Time  in  hours  

0  

10  

20  

30  

40  

50  

60  

0   20   40   60   80   100   120  

Tempe

rature

 o  C  

Time  in  hours  

Page 14: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

14 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Design Challenge #3 (temperature instability of preamps)

•  Temperature  stability  during  2  hour  vent  cycle  was  not  achieved  

•  Instrument  team  needs  to  be  able  to  take  data  once  acceptable  vacuum  is  reached  (est.  2-­‐3  hours)  

•  Time  constant  to  return  to  equilibrium    temperatures  >  24  hours  

45  46  47  48  49  50  51  52  53  54  

0   2   4   6  Tempe

rature    oC  

Time  in  Hours  

Repump  Begins  

Vent  Begins  

Page 15: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

15 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Effect of Temperature Drift on Calculated Neutron Position

•  Temperature  drii  of  preamps  is  known  to  have  detrimental  effect  on  calculated  event  posi)on  

•  Effect  much  more  pronounced  near  tube  ends  than  center  

0  

10  

20  

30  

40  

50  

60  

70  

46   48   50   52   54   56   58  Ch

ange  in  Peak  Po

si2o

n  (m

m)  

Temperature  (oC)  

tube  center   tube  end  

Page 16: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

16 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Design Challenge #3 Met with Electronic Solution

Preamplifier  modifica)on  provides  solu)on  to  peak  shii  problem  

                       capaci?ve  decoupling  of    

                       1st  stage  op  amp  leads  to            

                       excep?onal  peak  stability    

                       with  temperature  change  -­‐10  -­‐8  -­‐6  -­‐4  -­‐2  0  2  4  6  8  

10  

46   48   50   52   54   56   58  Ch

ange  in  Peak  Po

si2o

n  (m

m)  

Temperature  (oC)  

tube  center   tube  end  

Page 17: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

17 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Performance Stable Over Temperature Range Expected During Sample Change-Out

units RED (mm)

GREEN (mm)

BLUE (oC)

-­‐10  

-­‐9  

-­‐8  

-­‐7  

-­‐6  

-­‐5  

-­‐4  

-­‐3  

-­‐2  

-­‐1  

0  

1  

2  

3  

4  

5  

0   1   2   3   4   5   6   7   8  

Time  AAer  2  Hour  Vent  to  Atmosphere  (hours)  

Change  in  Peak  Posi)on    (mm)  

Change  in  Board  Temperature  Aier  Vent  (oC)  

Change  in  FWHM    (mm)  Vent  Begins  

Repump  Begins  

Page 18: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

18 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Redesign of Preamplifier Boards

•  Incorporated  decoupling  capacitor  modifica)on  •  Improved  protec)on  circuitry  to  buffer  against  HV  breakdown  (Corona)  

•  Plug-­‐in  connectors  to  facilitate  tray  removal  for  maintenance  

Page 19: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

19 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Upon further testing, vacuum group recommended removing all cabling from vacuum space

Rear  view  of  detector  module  showing  NW25  bellows  

Page 20: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

20 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

The first phase of 38 Corelli detector modules are currently undergoing assembly and testing, on track for an early CD-4 finish date in Feb 2014

Preparing for Installation

Page 21: Evolution of the Detector Module Design for CORELLI at SNS · Corelli*will*be*the*firstinstrumentin*the*world*dedicated*to* the*study*of*diffuse*scaering*with*energy*discriminaon*

21 Managed by UT-Battelle for the U.S. Department of Energy Presentation_name

Detector Development Team – Key Players

• George  Rennich  Lead  Engineer  

• Bill  Turner  Designer  

• Mark  Wendel  Thermal  Analysis  

•  Kevin  Berry,  Jus)n  Beal  Detector    Development  

• Vlad  Sedov  Electronics  Development  

•  Feng  Ye  Instrument  Scien?st