MEDSI2023 - List of Keywords (ECR)

Paper	Title	Other Keywords	Page
TUPYP005	On the Performance of Cryogenic Cooling Systems for Optical Elements at Sirius/LNLS	controls, cryogenics, operation, optics	40
	B.A. Francisco, M.P. Calcanha, R.R. Geraldes, L.M. Kofukuda, G.P. Lima, M. Saveri Silva, L.M. Volpe LNLS, Campinas, Brazil
	Funding: Ministry of Science, Technology and Innovation (MCTI) Sirius’ long beamlines are equipped with cryogenic cooled optics to take advantage of the Silicon thermal diffusivity and expansion at those temperatures, contributing to the preservation of the beam profile. A series of improvements was evaluated from the experience in the employment of such cooling systems during the early years of operation. The main topic refers to the prevention of instabilities in the temperature of the optics due to variations in the liquid nitrogen cylinder pressure, refill automation or progressive variations of the convective coefficient into the cryostat. This work discusses the performance of these systems after optimizing the pressure of the vessels and their control logics, the effectiveness of occasional purges, cool down techniques, and presents the monitoring interface and interlock architecture. Moreover, we present the reached solution for achieving higher beam stability, considering liquid nitrogen flow active control (commercial and in-house). Also propose the approach for the future 350 mA operation, including different cooling mechanisms.
	Poster TUPYP005 [1.250 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-TUPYP005
About •	Received ※ 24 October 2023 — Revised ※ 03 November 2023 — Accepted ※ 22 November 2023 — Issued ※ 18 July 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBM02	Development of the Bent Focusing Mirror in HEPS from Design to Test	focusing, SRF, synchrotron, photon	136
	M.W. Chen, M. Li, S. Tang, F.G. Yang IHEP, People’s Republic of China
	The focusing mirrors are important for each beamline in the 4th generation photon source. One bent focusing face-down mirror in HEPS is taken for an example to be introduced from the design to the test. The effect of the gravity of the mirror is considered in the design. Moreover, for the sake of the compromise between the processing and the precision, the polygonal structure is adopted. Also, the iteration of the solution is improved to increase the design efficiency. The results reveal that the theoretical precision of the mirror after bending can reach less than 100 nrad RMS. In the aspect of the mechanics, the scheme of four roller bender comes out to avoid the parasitic moment, and the movable component in the bender are all coated with the MoS2. As the type of the measurement is facing side which is different from the type of the actual condition, the effect of the gravity must be included in the metrology results. In the meantime, the stability and the repeatability are also measured. The result can be converged to around 200 nrad RMS, which is less than the required error. The stability, ¿R/R, can be constrained under the 0.6%, showing the outstanding performance.
	Slides WEOBM02 [3.638 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-WEOBM02
About •	Received ※ 25 October 2023 — Revised ※ 05 November 2023 — Accepted ※ 07 November 2023 — Issued ※ 16 April 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPP007	Optimizing Indirect Cooling of a High Accuracy Surface Plane Mirror in Plane-Grating Monochromator	synchrotron, optics, SRF, brightness	280
	J. Chen, X.W. Du, M.H. Lin, Q.P. Wang, Z. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: This work is supported by the Chinese Academy of Science (CAS) and the Anhui province government for key techniques R&D of Hefei Advanced Light Facility. For the cooling of the plane mirror in VIA-PGMs (var-iable-included-angle plane-grating monochromators), the top-side indirect cooling based on water is preferred for its advantages, such as cheaper, easier to use, smart notches, etc, when compared to the internal cooling. But it also arises challenges to control the RMS residual slope error of the mirror, whose requirement is less than 100 nano-radian. This requirement is even hard to fulfill, when combined with 1) the asymmetry thermal defor-mation on the meridian of the footprint area during the energy scanning, 2) the high heat load deduced by the synchrotron light and 3) the no obvious effects of the classical optimizations, such as increasing footprint size, cooling efficiency or adding smart notches. An effective way was found after numerous attempts, which is to make the footprint area far from the mirror¿s edge to reduce the asymmetry of the thermal deformation except for leading to a longer mirror. This paper will illustrate how the asymmetry affects the mirror¿s residual slope error and then, focus on the relationship among the asymmetry of cooling and the distance to provide a ref-erence for optical cooling.
	Poster THPPP007 [1.805 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-THPPP007
About •	Received ※ 26 October 2023 — Revised ※ 06 November 2023 — Accepted ※ 08 November 2023 — Issued ※ 04 March 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPP047	NEG Film Development and Massive Coating production for HEPS	vacuum, cathode, synchrotron, storage-ring	343
	Y.S. Ma, H. Dong, D.Z. Guo, P. He, F. Sun, Y.C. Yang IHEP, Beijing, People’s Republic of China T. Huang IHEP CSNS, Guangdong Province, People’s Republic of China
	Massive production facilities of NEG coated vacuum chambers have been developed for HEPS in Huairou, Beijing, which based on the NEG coating prototypes of HEPS-TF. The facilities can achieve simultaneous coating of 16~20 vacuum chambers of HEPS including irregular shaped vacuum chambers. The pumping per-formance of the NEG coated vacuum chambers has been measured by test facilities. After heating at 200°C for 24 hours, the highest pumping speed of H₂ is about 0.65 l/scm², and the highest capacity of CO is about 1.89×10^-5 mbar·L/cm². The lifetime is more than 20 cycles of air exposure and re-activation. The pumping performance meets the design requirements of HEPS. Currently the NEG coated vacuum chambers are applied to the storage ring of HEPS.
DOI •	reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-THPPP047
About •	Received ※ 02 November 2023 — Revised ※ 09 November 2023 — Accepted ※ 22 November 2023 — Issued ※ 18 July 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUPYP005

On the Performance of Cryogenic Cooling Systems for Optical Elements at Sirius/LNLS

controls, cryogenics, operation, optics

40

B.A. Francisco, M.P. Calcanha, R.R. Geraldes, L.M. Kofukuda, G.P. Lima, M. Saveri Silva, L.M. Volpe
LNLS, Campinas, Brazil

Funding: Ministry of Science, Technology and Innovation (MCTI)
Sirius’ long beamlines are equipped with cryogenic cooled optics to take advantage of the Silicon thermal diffusivity and expansion at those temperatures, contributing to the preservation of the beam profile. A series of improvements was evaluated from the experience in the employment of such cooling systems during the early years of operation. The main topic refers to the prevention of instabilities in the temperature of the optics due to variations in the liquid nitrogen cylinder pressure, refill automation or progressive variations of the convective coefficient into the cryostat. This work discusses the performance of these systems after optimizing the pressure of the vessels and their control logics, the effectiveness of occasional purges, cool down techniques, and presents the monitoring interface and interlock architecture. Moreover, we present the reached solution for achieving higher beam stability, considering liquid nitrogen flow active control (commercial and in-house). Also propose the approach for the future 350 mA operation, including different cooling mechanisms.

Poster TUPYP005 [1.250 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-TUPYP005

About •

Received ※ 24 October 2023 — Revised ※ 03 November 2023 — Accepted ※ 22 November 2023 — Issued ※ 18 July 2024

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBM02

Development of the Bent Focusing Mirror in HEPS from Design to Test

focusing, SRF, synchrotron, photon

136

M.W. Chen, M. Li, S. Tang, F.G. Yang
IHEP, People’s Republic of China

The focusing mirrors are important for each beamline in the 4th generation photon source. One bent focusing face-down mirror in HEPS is taken for an example to be introduced from the design to the test. The effect of the gravity of the mirror is considered in the design. Moreover, for the sake of the compromise between the processing and the precision, the polygonal structure is adopted. Also, the iteration of the solution is improved to increase the design efficiency. The results reveal that the theoretical precision of the mirror after bending can reach less than 100 nrad RMS. In the aspect of the mechanics, the scheme of four roller bender comes out to avoid the parasitic moment, and the movable component in the bender are all coated with the MoS2. As the type of the measurement is facing side which is different from the type of the actual condition, the effect of the gravity must be included in the metrology results. In the meantime, the stability and the repeatability are also measured. The result can be converged to around 200 nrad RMS, which is less than the required error. The stability, ¿R/R, can be constrained under the 0.6%, showing the outstanding performance.

Slides WEOBM02 [3.638 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-WEOBM02

About •

Received ※ 25 October 2023 — Revised ※ 05 November 2023 — Accepted ※ 07 November 2023 — Issued ※ 16 April 2024

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPP007

Optimizing Indirect Cooling of a High Accuracy Surface Plane Mirror in Plane-Grating Monochromator

synchrotron, optics, SRF, brightness

280

J. Chen, X.W. Du, M.H. Lin, Q.P. Wang, Z. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: This work is supported by the Chinese Academy of Science (CAS) and the Anhui province government for key techniques R&D of Hefei Advanced Light Facility.
For the cooling of the plane mirror in VIA-PGMs (var-iable-included-angle plane-grating monochromators), the top-side indirect cooling based on water is preferred for its advantages, such as cheaper, easier to use, smart notches, etc, when compared to the internal cooling. But it also arises challenges to control the RMS residual slope error of the mirror, whose requirement is less than 100 nano-radian. This requirement is even hard to fulfill, when combined with 1) the asymmetry thermal defor-mation on the meridian of the footprint area during the energy scanning, 2) the high heat load deduced by the synchrotron light and 3) the no obvious effects of the classical optimizations, such as increasing footprint size, cooling efficiency or adding smart notches. An effective way was found after numerous attempts, which is to make the footprint area far from the mirror¿s edge to reduce the asymmetry of the thermal deformation except for leading to a longer mirror. This paper will illustrate how the asymmetry affects the mirror¿s residual slope error and then, focus on the relationship among the asymmetry of cooling and the distance to provide a ref-erence for optical cooling.

Poster THPPP007 [1.805 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-THPPP007

About •

Received ※ 26 October 2023 — Revised ※ 06 November 2023 — Accepted ※ 08 November 2023 — Issued ※ 04 March 2024

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPP047

NEG Film Development and Massive Coating production for HEPS

vacuum, cathode, synchrotron, storage-ring

343

Y.S. Ma, H. Dong, D.Z. Guo, P. He, F. Sun, Y.C. Yang
IHEP, Beijing, People’s Republic of China
T. Huang
IHEP CSNS, Guangdong Province, People’s Republic of China

Massive production facilities of NEG coated vacuum chambers have been developed for HEPS in Huairou, Beijing, which based on the NEG coating prototypes of HEPS-TF. The facilities can achieve simultaneous coating of 16~20 vacuum chambers of HEPS including irregular shaped vacuum chambers. The pumping per-formance of the NEG coated vacuum chambers has been measured by test facilities. After heating at 200°C for 24 hours, the highest pumping speed of H₂ is about 0.65 l/scm², and the highest capacity of CO is about 1.89×10^-5 mbar·L/cm². The lifetime is more than 20 cycles of air exposure and re-activation. The pumping performance meets the design requirements of HEPS. Currently the NEG coated vacuum chambers are applied to the storage ring of HEPS.

DOI •

reference for this paper ※ doi:10.18429/JACoW-MEDSI2023-THPPP047

About •

Received ※ 02 November 2023 — Revised ※ 09 November 2023 — Accepted ※ 22 November 2023 — Issued ※ 18 July 2024

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)