1. Design and fabrication of liquid nitrogen cooled double crystal monochromator for PLS-II
Seungyu Rah (Pohang Accelerator Laboratory, POSTECH, Korea)
Nov
ICABU2014
__________________________________________ICABU Seungyu Rah

2. __________________________________________ICABU 2014 Seungyu Rah
Contents
Introduction
PAL’s effort for developing/ standardizing common beamline instruments
PAL’s effort for developing mirror manipulator system
Development of Double crystal monochromator
Discussion
Summary
__________________________________________ICABU Seungyu Rah

3. Introduction - Beamlines at Pohang Light Source
May 2013
30 working
23 x-ray
11 soft x-ray
19 I/D BLs
__________________________________________ICABU Seungyu Rah

4. Introduction - Beamlines
Beamline in synchrotron Light Source
Is a unit of experimental system
Is consisted of
Safety system at front-end
Photon beam manipulation system
Experimental system
Safety system
Vacuum safety
High energy radiation safety
Thermal heat
Common parts
Photon beam manipulation system
Spatial filtering(Slits)
Deflection and focusing(Mirrors)
Monochromatization(Monochromator, Grating/Crystal)
Common parts
High precision & stability
Experimental system
Sample
Detector
Environmental control(temperature/Pressure)
Mechanical motion(Sample/detector)
High precision and stability
Unique design for the purpose
__________________________________________ICABU Seungyu Rah

5. __________________________________________ICABU 2014 Seungyu Rah
Introduction - construction of beamline and keeping own design of instruments
Construction of beamline
Costs ~ $5M
Needs ~3 years
Needs 6~10 man-year
Man power dedicate to construction and operation
Developing/ Keeping/ transferring own design of Instruments
Shares
Modular Design
Same parts
Saves cost for
Manufacturing
Maintenance
Keeping spare part
Reduces time for
Delivery
Maintenance
Helps
Better understanding of instruments
Improvement of instruments
Development of similar instruments
May limit the choice
Hidden cost
Own test system
Maintaining the technique
Dedicated manpower
Proto-type
Trial and fails
__________________________________________ICABU Seungyu Rah

6. PAL’s effort for developing/ standardizing common beamline instruments
Software
EPICS, LabView, Mathlab, SPEC based programs
Electronic/electric instruments
Baking controller
Motor controller/driver
Interlock system
Photon beam position monitor
Insertion devices
Undulator
In-vacuum undulator
wiggler
Mechanical system
Support structure
Slit,
photon shutter,
safety shutter
optical table,
experimental table
fast closing shutter
Optical instruments
Mirror manipulator
Monochromator(Crystal)
__________________________________________ICABU Seungyu Rah

7. PAL’s effort for developing mirror manipulator system
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8. PAL’s effort for developing mirror manipulator system
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9. PAL’s effort for developing mirror manipulator system
1st trial in 1994
consistent trial and improvement in design, since 2000
By 2011, there were 66 mirror system have been built
PAL owns the design and improves
Adjustment of mirror position : 5 deg. Of freedom
Adjustment of bending radius
Need high precision and stability
One of the most successful system
The contractor has been chosen by biding, at the beginning stage
Later, the contractor has been fixed for the performance of the system
By the hand on experience, the contractor started commercial production
More than 15 sets has been sold to outside PLS
__________________________________________ICABU Seungyu Rah

10. Development of Double crystal monochromator
__________________________________________ICABU Seungyu Rah

11. Development of Double crystal monochromator
Experience(not fully tested)
1st trial for DCM in 1994
2nd trial for DCM in 2000
Two more for DMM
Motive
PLS-II upgrade(‘09-’11)
Change of beam parameter
6 BLs moved from BD to ID
Short of budget
Limited choice
Requirement
Construction of 10 set
Within 3 years
Liquid nitrogen cooled DCM
Fixed beam offset
Reliable performance
Strategy(Systematic approach)
Requirement is clear
Known working principle
High precision(Order 1 higher than necessary resolution)
Stability(mechanical/thermal)
As simple design as possible
Depend on liable parts
Monitoring system(motion/temperature)
Make proto-type
Prove the performance by test
Limited man-power
Schematic design and test
4-physicists
1-electrical/software engineer
Local contractor
Detail design
Fabrication
__________________________________________ICABU Seungyu Rah

12. Development of Double crystal monochromator
Workscope of PAL
Choice of contractor
Fix the specification
Schematic design
Choice of parts
Order the parts
Order Proto-type
operation software
Lab test
Beamline test
Evaluation and modification
Order for duplication
BL operation of proto-type
Workscope of contractor
Detail design(CAD)
Fabrication
Precision Assembly(CMM)
Integration of electronics system
Primary motion test
Help the lab test
Installation
Modification of detail design
Duplication
__________________________________________ICABU Seungyu Rah

13. Development of Double crystal monochromator
11 sets of DCMs have been fabricated
3 kind of DCMs have been fabricated
Single type DCM : 8 sets
Dual type DCM : 1 set
Asymmetrical cut DCM : 2 sets
8 sets of DCMs are in operation
6 single type DCMs, since Feb. 2012
2 asymmetrical cut DCM: since Aug. 2012
1 set of single type DCM is in commissioning, since Feb. 2014
Fabrication cost
270K US$/set( 1/3~1/2 of commercial system by price of 2011)
Parts
Fabrication
Assembly
Installation
Manpower
3 man-year of physists
0.5 man-year of engineer
1 set of CCM is under fabrication
The technical transfer is going on to the contractor for the design, test and evaluation technique
__________________________________________ICABU Seungyu Rah

14. Discussion developing and improving an instrument for BL
Development requires
Big motivation
Experience
Time
Effort
Money
Benefits
Save fabrication cost
Save maintenance cost
Easy maintenance for the clones
Easy development of similar system
To keep or improve the technique, you need
Continuous attention for
Demand
New technique/parts
idea
Dedicated manpower
To keep test facility
Technical transfer to contractor
Can Create new business opportunity
Can take over your effort to keep or improve the technique
Additional collaboration must be beneficial for both parties
__________________________________________ICABU Seungyu Rah

15. __________________________________________ICABU 2014 Seungyu Rah
Summary
PAL’s effort to develop/standardize beamline components is introduced
The development of DCM is introduced
The necessity of technical transfer of the development to industry is discussed
__________________________________________ICABU Seungyu Rah

16. __________________________________________ICABU 2014 Seungyu Rah
Thank you for your attention !!
__________________________________________ICABU Seungyu Rah