Author: Feng, G.Y.
Paper Title Page
MOPAB112 A Modified Hybrid 6BA Lattice for the HALF Storage Ring 407
 
  • Z.H. Bai, G.Y. Feng, T.L. He, W. Li, W.W. Li, G. Liu, Z.L. Ren, L. Wang, P.H. Yang, S.C. Zhang, T. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  In this paper, we pro­pose a mod­i­fied hy­brid 6BA lat­tice as the base­line lat­tice of the Hefei Ad­vanced Light Fa­cil­ity (HALF) stor­age ring. Sim­i­lar to the Di­a­mond-II lat­tice, the pro­posed lat­tice cell has one long straight sec­tion and one mid-straight sec­tion; but the two bend units ad­ja­cent to the mid-straight are LGB/RB units (LGB: lon­gi­tu­di­nal gra­di­ent bend, RB: re­verse bend), which can give both lower emit­tance and shorter damp­ing times. The de­signed HALF stor­age ring, with an en­ergy of 2.2 GeV and 20 lat­tice cells, has a nat­ural emit­tance of about 85 pm·rad.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB112  
About • paper received ※ 15 May 2021       paper accepted ※ 20 May 2021       issue date ※ 01 September 2021  
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TUPAB265 Bunch Lengthening of the HALF Storage Ring in the Presence of Passive Harmonic Cavities 2082
 
  • T.L. He, Z.H. Bai, G.Y. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  A pas­sive 3rd har­monic RF sys­tem, being nec­es­sary for the Hefei Ad­vanced Light Fa­cil­ity (HALF) stor­age ring under de­sign, will be em­ployed to lengthen the bunches for sup­press­ing the in­tra­beam scat­ter­ing and im­prov­ing the beam life­time. How­ever, the tran­sient beam load­ing due to the fun­da­men­tal mode may sig­nif­i­cantly re­duce the bunch length­en­ing. Since the scale of tran­sient ef­fects is pro­por­tional to R/Q, the ef­fects of R/Q on bunch length­en­ing, in uni­form fill pat­tern with the near-op­ti­mum con­di­tion ful­filled, are an­a­lyzed by multi­bunches mul­ti­par­ti­cles track­ing sim­u­la­tion. It in­di­cates that the pas­sive su­per­con­duct­ing har­monic cav­ity with a lower R/Q is pre­ferred by HALF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB265  
About • paper received ※ 16 May 2021       paper accepted ※ 18 June 2021       issue date ※ 20 August 2021  
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TUPAB368 Design of the Longitudinal Gradient Dipole Magnets for HALF 2378
 
  • M.Y. Mingyao
    Wang, Hefei, People’s Republic of China
  • G.Y. Feng, Z.L. Ren, H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  Hefei Ad­vanced Light Fa­cil­ity (HALF) is the fourth gen­er­a­tion dif­frac­tion-lim­ited stor­age ring light source pro­ject in China. The lat­tice of the stor­age ring con­sists of six dif­fer­ent dipoles with lon­gi­tu­di­nal gra­di­ents. The lon­gi­tu­di­nal-gra­di­ent dipoles (LGBs) are per­ma­nent mag­nets. This paper pre­sents the de­signed con­struc­tion of LGBs and the mag­netic field re­sults using OP­ER­A3D. By op­ti­miz­ing the shape of the polar sur­face, the mag­netic field uni­for­mity is op­ti­mized to about 5×10-4. With some mov­able ad­just­ing block, the mag­netic field can be con­trolled ac­cu­rately. The tem­per­a­ture sta­bil­ity of the mag­net is bet­ter than 0.0074 T*mm/°C by set­ting tem­per­a­ture com­pen­sat­ing shunt.  
poster icon Poster TUPAB368 [0.862 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB368  
About • paper received ※ 15 May 2021       paper accepted ※ 02 June 2021       issue date ※ 10 August 2021  
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WEPAB264 MOGA Optimization of Superconducting Longitudinal Gradient Bend Based on NbTi Wire 3257
 
  • C. Chen, Z.H. Bai, G.Y. Feng, Z.L. Ren, Zh.X. Tang, L. Wang, H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  Funding: Work supported by National Key Research and Development Program of China, (2016YFA0402001)
Multi-bend achro­mat lat­tices with unit cells have been used in dif­frac­tion-lim­ited stor­age ring de­signs. The lon­gi­tu­di­nal gra­di­ent bend can re­duce the hor­i­zon­tal emit­tance below the the­o­ret­i­cal min­i­mum of a given mag­net struc­ture, and gen­er­ally the hor­i­zon­tal emit­tance re­duces with the peak field grows. There­fore su­per­con­duct­ing lon­gi­tu­di­nal gra­di­ent bend (SLGB) can pro­duce higher peak field value and quasi-hy­per­bolic field pro­file to min­i­mize emit­tance at lo­ca­tion of ra­di­a­tion and gen­er­ate bet­ter hard X-rays. NbTi con­duc­tor, rather than Nb3Sn con­duc­tor, is se­lected to keep the de­sign and man­u­fac­ture of SLGB mag­net as sim­ple as pos­si­ble. In this paper, how the field pro­files of race-track type coil and so­le­noid coil change with their geo­met­ric pa­ra­me­ters is stud­ied, and multi-ob­jec­tive ge­netic al­go­rithm is used to op­ti­mize SLGB mag­net struc­ture con­sid­er­ing Hefei Ad­vanced Light Fa­cil­ity lat­tice de­sign de­mand and NbTi crit­i­cal cur­rent. 		 
poster icon Poster WEPAB264 [1.476 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB264  
About • paper received ※ 14 May 2021       paper accepted ※ 05 July 2021       issue date ※ 14 August 2021  
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