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0af43a3e-7f1f-462a-8dcb-56034148e5c0 | ELECTROSTATIC DUST LOFTING:
A POSSIBLE CAUSE FOR BEAM LOSSES AT CERN’S LHC
A. Elliott, Florida Institute of Technology, Melbourne, USA, X. Wang, M. Horanyi , K. Taylor,
Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder,
Colorado, USA, R. Schmidt, T . U. Darmstadt, Darmstadt, Ge... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
9e578cac-ae9b-4dd2-bc15-ef47d0fcb7cd | and can detach from the chamber wall by the electric field
of the beam. To test this hypothesis, we performed experi-
ments to study the electros tatic lofting of dust particles
from a conducting surface. A monolayer of SiO2 particles
with a diameter of <44 um is deposited on such a surface
and exposed to an electr... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
5c2db9ed-7ada-4fe5-bb80-53a571b23ba7 | the mechanism of how dust particles can enter the LHC
beam.
DUST IN THE LHC
Dust grains interacting with the beam in particle accel-
erators are the cause of detrimental effects such as beam
losses, emittance growth, pressure bursts, magnet quenches
and even damage of accelerator components.
During CERN's Large... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
0116b5c8-332a-4a33-8704-d7af0343b20a | ceed a threshold, the beams are extracted to prevent detri-
mental effects such as magnet quenches.
The presence of dust grains in the LHC vacuum chamber
is not fully understood. Observations suggest that dust was
introduced during assembly of the machine. It seems una-
voidable, even with careful cleaning measure... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
30f7fd6e-faa3-4e00-840b-1fc9f48ffed5 | grains leading to observable beam losses is believed to be
in the order of 1 µm − 100 µm. The precise composition of
the contaminants is not known, although metallic and ce-
ramic components have been found.
There is evidence for the presence of ceramic dust in the
LHC. In 2010 and 2011, many UFOs were observed a... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
8c419f6c-21e5-4fe8-8ef9-b41876322c07 | the fast rise times observed, it has been shown that an ini-
tial negative charge is required on the grains [4]. This is in
line with observations indicating that dust grains can enter
the beam from a position not directly above the beam and
are attracted to wards the beam due to their negative charge.
The charg... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
4c72761d-ebd2-4ed9-8845-9ce76d23a4b0 | charging current.
3. Photoelectric emission: Photons, typica lly gener-
ated by synchrotron radiation, excite electrons that
then escape the grain due to the photoelectric effect.
This mechanism leads to a positive charging cur-
rent. These electrons can be captured by other grains
and lead to a negative charg in... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 0 |
113852b4-fecf-4b2c-93a5-cbaf0651ee3a | [6] [7] and in future accelerators such as the Future Circu-
lar Collider (FC C [8]), it is important to understand how
dust grains enter the beams in an accelerator .
DUST IN SPACE RESEARCH
Levitation of dust grains has been observed for many
years in laboratory studies in the Laboratory for Atmos-
pheric and Spa... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 1 |
a27ff60e-eebe-4f3a-9622-aaa0d23f3d80 | negative charges on the surr ounding particles leading to
strong electric repulsive forces, and subsequent dust grain
lofting, in line with experimental observations [9].
There are many similarities between dust grains on plan-
etary bodies and accelerato rs (e.g., size, material). One dif-
ference is that in acc... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 1 |
ae12aa64-ea5e-4cdf-8e6b-8683097bf75d | emitted by the protons . The electric field of the proton
beam attracts negatively charged dust grains.
Observations of dust lofting at LASP offer a new way to
study the detachment of dust grains from the vacuum
chamber in particle accelerators and have triggered exper-
iments conducted at LASP in collaboration wi... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 1 |
0eb500d9-0c13-4c93-8a86-494f988e206b | a metallic mesh. The distance between mesh and
plate is 0.5-1 cm.
2. Pump chamber down to less than 5∙10−6 Torr.
3. Ground the mesh above the plate. Charge the dust
by a tungsten filament that generates a beam of
60-120 eV energy electrons with a current of up to
180 mA.
4. Turn off charging. Apply a bias vol... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 1 |
3d120a9d-be44-4167-b452-b638bd450719 | High Voltage Lofting
With an electric field, the dust grains travel in vertical
trajectories [10]. The charge 𝑞 is calculated from the equa-
tion of motion
𝐹𝑦=𝑚𝑎𝑦=𝑚𝑑𝑣𝑦
𝑑𝑡=𝑞𝐸−𝑚𝑔 (1)
with the electric field
𝐸=𝑉𝑑⁄, 𝑎𝑦 (2)
the vertical acceleration measured from the recorded tra-
jectori... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 1 |
58b6959c-480b-4c84-9f5c-38fbb75e0f43 | Lofting during Charging
Without high voltage, dust grain trajectories are para-
bolic (see Figure 5). The launch velocity is calculated by
video analysis . In Figure 6, the launch velocity for our ex-
periments is compared to data from previous experiments
[10], where lofting was observed for multi -layer dust.
... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 2 |
ccaff45c-795e-4709-9632-1ef4daacf320 | force between grain and conducting plate that tend to pre-
vent lofting.
Without insulating surface b etween dust and conducting
surface, o nly a small fraction of the dust grains is lofted.
When the experiment is repeated with the same dust sam-
ple, the lofting rate is not very reproducible.
The lofting rate is... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 2 |
eb7fa660-d4b6-4bc8-952b-7ec612ba3f19 | In the case of charged grains, the image charges and the
resulting image force al so counteract lofting.
Figure 6: Initial launch velocity for multi -layer dust ( left)
versus monolayer dust ( right). The theoretical curves (solid
lines) for Lunar Simulants and Silica Microspheres are
taken from [10]. g account... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 2 |
24f3bef2-013c-4f29-a68c-82b0eeb961f0 | nate. In both cases, lofting is expected to be prevented.
It is surprising that for monolayer dust , lofting occurs
during the ch arging process even without an electric field.
The mechanics is not fully understood and requires further
investigations. C harge, shape, and material parameters of
the dust grains ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 2 |
3b57496c-1a4d-460c-9dca-0ff863c4e864 | with other energies ranging from 60 eV to 120 eV . We the-
orize the presence of a space -charge limited (SCL) plasma
sheath [11] between the plate and the mesh, which would
explain why the 80 eV charging potential is preferred.
Our results provide experimental evidence that dust par-
ticles can be detached from... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 2 |
d622311f-d483-4cb0-891d-37ffb57a01e6 | REFERENCES
[1] A. Lechner et al, “Dust -induced beam losses in the
cryogenic arcs of the CERN large hadron collider ”,
Phys. Rev. Accel. Beams, vol. 25, p. 041001, Apr .
2022.
[2] B. Goddard et al, "Transient beam losses in the lhc
injection kickers from micron scale dust particles ",
in Proc.of IPAC '12, N... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 3 |
a6b6cc43-312b-48d0-82ba-1d9126a40e2c | collider (HL-LHC): Technical design report ", Geneva: CERN, 2020.
doi:10.23731 /CYRM -2020 -0010
[7] P. Lindstrom et al, “Fast failures in the LHC and
the future high luminosity LHC,” Phys. Rev. Accel.
Beams, vol. 23, p. 081001, Aug . 2020.
[8] FCC Collaboration, "The hadron collider, future
circular collid... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 3 |
308fba79-c4aa-4341-8518-faa14e8ba285 | p. 113972, 2020.
[11] X. Wang, J. Pilewskie, H. -W. Hsu and M. Horányi,
“Plasma potential in the sheaths of electron -
emitting surfaces in space,” Geophys. Res. Lett. ,
vol. 43, pp. 525 -531, 2016. | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA065.pdf | 3 |
a783f977-7155-4ffd-bf4b-60719fb4ea78 | EXPERIMENTAL MEASUREMENTS ON IMPEDANCE AND BEAM
INSTABILITY IN BEPCII
J. L. Su1, Y. D. Liu∗, D. Yin, Z. Liu, D. C. Zhu, H. Z. Ma, G. Lei, J. H. Yue,
H. P. Geng, W. Zhang, Institute of High Energy Physics, Beijing, China
1also at University of Chinese Academy of Sciences, Beijing, China
C. Y. Que, Wuhan University, Wuha... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 0 |
c780a5fd-bd75-4f1e-a23f-1465e556c267 | versenarrowbandimpedance. Thelongitudinalbroadband
impedancecouldinducebunchlengthened,thetransverse
broadband impedance could cause tune shift, and narrow-
band impedances could generate muti-bunched coupled
mode. Itwasconfirmedthatthetransversecoupled-bunchin-
stabilityhasbeenanimportantlimitationoncurrentandcol-
lis... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 0 |
9e2e7d1e-b085-4173-a3ee-754ea3372033 | 0.06714M Ω/min the vertical plane. With the spectrum
analyzer, the oscillation mode distribution caused by the
longitudinal narrowband impedance was studied and it was
confirmed that the longitudinal feedback system is effective
enoughtosuppressthebeaminstabilities. Withthebunch-
by-bunch measurement system, the most u... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 0 |
3a964e9a-9bfd-4d2a-9dde-7cc772df36af | longitudinal broadband impedance, transverse broadband
∗liuyd@ihep.ac.cnimpedance, longitudinal narrowband impedance, and trans-
verse narrowband impedance.
Longitudinal Broadband Impedance
Duringtheexperiment, asinglebunch wasinjectedinto
BPR or BER and the bunch length was measured by the
streak camera. The current w... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 0 |
93f5da0c-9573-4d21-b39e-5b4e79ce2825 | Parameter Positron ring Electron ring
Revolution frequency 1.2621MHz
Momentum compactor 0.017976 0.017639
Longitudinal tune 0.0299 0.0296
Energy spread 5.222341E-4 5.462391E-4
TheexperimentparametersarelistedinTable1andthe
measuredresultsareshowninFig.1. Aftertakingthenatural
bunchlengthasuncertainparameterandfittingth... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 0 |
24ec1a3e-9b64-4b18-ae2c-da2291c095aa | (a) BPR
(b) BER
Figure 1: Experiment data and fitting.
Transverse Broad Impedance
The relationship between the betatron tune of a single
bunch and current can be expressed as [3]
𝑑𝜈𝛽
𝑑𝐼=−1
4√𝜋𝑐2
0
𝐸𝑘
𝑒
𝜈𝛽𝜔2
0𝜎𝑙(𝑍⊥
1)𝑒𝑓𝑓,(2)
where𝐼isthebunchcurrent, (𝑍⊥
1)𝑒𝑓𝑓isthetransversebroad
impedance,𝐸𝑘i... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 1 |
59838e82-da6e-4bc9-bfb5-2bcae6553eb6 | thebunchseparately. ThetunedirectfromLibrasystemand
rawoscillationinformationcanbeobtained. Byfittingthe
beam current and measured tune with Eq.(2), we can obtain
thetransversebroadimpedancesofBERandBPR,asshown
in Table 3 and Fig.2
With the comparison, it is clear that the vertical broad
impedancesofbothringsarelargert... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 1 |
252a01c1-7ff8-46e9-a2be-10c2d2549481 | methodData
sourcePositron ring Electron ring
X Y X Y
injection
kickerLibra 27.57 47.51 44.44 70.15
FFT 24.21 46.88 41.53 70.36
feedback
kickerLibra 30.9 57.59 39.98 64.44
FFT 30.92 58.13 42.97 63.61
Average 28.4 52.53 42.23 67.14
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
Figure 2: Transverse tune of single bunch vs current:
... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 1 |
3f2a1e37-28c8-4730-bb6b-36c64ce64c6a | Longitudinal Narrowband impedance
Since the beam current threshold is very low with the
transversefeedbacksystemoff,andthelongitudinalinstabil-
itywouldbemitigatedifthelongitudinalfeedbacksystem
is on, we decide to keep the transverse feedback on and the
longitudinalfeedbacksystemofftomeasurethelongitudi-
nalmodedistri... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 1 |
1871a6d3-b503-4c80-ae94-5bf10f954fef | (a)
(b)
Figure 3: “Mode-current-amplitude”: (a) BPR;(b) BER.
AsshowninFig.3,boththeBPRandBERbegintodis-
playlongitudinalcoupledoscillationmodesatthecurrent
of250 mA. When the current increases, the amplitude of
themodesalsoincreases. ThecurrentthresholdofBERis
800 mA, much larger than the threshold of BPR, 600 mA.
The... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 2 |
7d0cd140-ddf8-4bfa-b1c6-73bbe99545f5 | bunch feedback system at the same time. By recording
the bunchby bunch oscillation,theposition oscillationand
modegrowthcanbeobtained. SuchameasurementforBER
at706 mAin the horizontal plane is shown in Fig.4. It is
obvious thatthe mode78 isthe mostunstablemode.
Through mode analysis, we finally found that the most
unst... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 2 |
a6f9aedd-3b8a-4079-ada4-3aaad587d267 | in Proceedings of the Second Asian Particle Accelerator Con-
ference, Beijing, China, pp. 386 (2001).
[2]BEPCII Group. BEPCII Design Report. Institute of High
Energy Physics, CAS, November 2003.
[3]M. Huck, J. Bahrdt, H. Huck et al., Transverse Broad-
band Impedance Studies of the In-vacuum Cryogenic Un-
dulator at BE... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA067.pdf | 2 |
0adeb9d9-7325-4a28-9e4c-5e0bf67f6670 | THE INVESTIGATION OF CAVITY FREQUENCY INSTABILITY
INDUCED BY VIBRATIONS
F. Yan†, J. Dai , Q. Wang, P . Zhang, N . Zhou, Q . Ma, W . Huang, X . Huang ,
Key Laboratory of Particle Acceleration Physics and Technology,
Institute of High Energy Physics, Beijing, China
Abstra... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 0 |
5eff4bed-423a-4085-b8a7-d6424e6708ba | PCB sensors were fixed on the rack which is connected
directly with the cavity pipe. The whole starting up process
of the BEPC- II after long sh utting down were monitored
for determining the vibration sources. To investigate the
sensitivity of the cavity under different vibrations, 500 mV
bias input voltage were... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 0 |
7b490b68-ef80-4195-8331-a25032244dbe | designed emittance of the ring, the problem s caused by the
ambient ground motion have been increasingly highlighted. HEPS (High Energy Photo Source) has a very
challenging beam stability requirements with the
transverse beam emittance specification of 0.1 nm.rad and
designed natural emittance of ~0. 03 nm.rad w... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 0 |
4730185b-1cc6-4036-9a38-d4ced5dd40fd | storage ring . During operation of the SC cavit ies of BEPC-
II, sideband close to 46 Hz and 50 Hz (and its multiplier:
100 Hz et al.) were found as shown in Fig. 1.
To lower down the sideband, and enhance the frequency
controlling accuracy, a lot of effort s were put in to trace the
vibration sources. On on... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 0 |
9ec14622-300a-4f5d-9681-b6c9b0611b72 | In this paper, the second section shows the sensitivity of
the cavity to the vibration sources with different
frequencies. The third section presents the measurement
methods used for tracing the vibration so urces and the
vibration sources determined up to now.
SENSITIVITY OF THE CA VITY TO
VIBRATIONS
To measu... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 0 |
b907a99c-5bad-4787-b15f-525ca3b59dd8 | simulating analysis as shown in Fig, 2 [3], the rack on
Figure 2 [3]: Lowest mechanical modes of the 499.8 MHz
SC cavity. (a) Mode 1. (b) Mode 2. (c) Mode 3. (d) Mode
4. (e) Mode 5. (f) Mode 6.
Figure 3: Vibration sensors on the rack connecting to the
left side beam pipe of the BEPC- II SC cavity.
Fi... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 1 |
5b77ae39-45b4-4345-8e6b-4099af5fb6ac | vibrations with different frequencies, 500 m V (peak to
peak: 1V) bias input voltage s with frequenc ies from 10 Hz
up to 150 Hz with step o f 0.5 Hz were added on the piezo ,
produc ing longitudin al beating on the cavity. The piezo
beating period is 30 s for e ach frequency. From Fig. 4 we
can see that ther... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 1 |
049e9553-609d-493b-9faa-c693a3d22a6a | be amplified. Although cavity is beat longitudinally using
piezo, there are also vertical motions in the meanwhile as
shown in Fig. 5, the red curve . But the vertical input force
on the cavity are not ensured to be identical for each frequency. So, vertical sensitive vibration frequency
cannot be concluded from... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 1 |
ac112715-5606-4dec-8064-8f6b18489e6e | BEPC- II SC cavity.
As mentioned in the previous session, PCB sensors were
stick on the rack of the SC cavity which connect s with the
cavity pipe for monitoring the vibration variation during
the whole starting up process of the BEPC -II after long
shutting down. A s shown in Fig. 5, there are two major
noise... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 1 |
363a4d7d-994b-4c07-9e34-0311c13d4705 | water -cooling pipes of magnet and vacuum system as
Figure 6: The accelerometers PCB393B04 on the cooling
water pipe of the magnet and vacuum system .
Figure 7: The vibration PSD spectrum of the
accelerometers on the cooling water pipe of the magnet
(upper figure) and of the vacuum system (lower figure). ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 2 |
758c2a02-d76a-4d58-81e7-cdaf37bfbfdc | noise, it probably is the second harmonics of a 50 Hz
vibration source. Because in one aspect, there is rarely 100
Hz source in the tunnel, on the other hand, the second
harmonics of 50 Hz (100 Hz) can be magnified as it is close
to the mechanical mode of the cavity. That might be the
reason why 100 Hz is the do... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 2 |
dfbdc837-0636-4caa-b942-2830c6d8eb50 | the cavity. It is also worthy to mention that pumps installed
vertically have less domination to the vibration on the cavity than horizontal pumps , although cooling water
pump of RF transmitter for SC cavity is closer to the
BEPC- II cavities than other pumps , the noise level is less
than other horizontal pumps ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 2 |
a341798f-7e91-4b26-a3b9-889d4e1cb626 | 120 Hz and 15 0 Hz were found which are agreed with the
simulations. During monitoring t he whole starting up
process of the BEPC -II after long shutting down a few
vibration sources were identified, but the 45.9 Hz and 100
Hz vibration sources are still under investigati on.
REFERENCES
[1] G. Xu et al., “Progr... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA068.pdf | 2 |
b05d15ca-8771-49a3-b8b7-b586d4b0c696 | DESIGN OF TRANSVERSE FEEDBACK KICKERS
FOR THE HEPS STORAGE RING
X. Y. Liu∗, Y. F. Sui, J. X. Zhao, T. G. Xu, J. H. Yue, J. S. Cao
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
Abstract
The High Energy Photon Source is a 6 GeV synchrotron
radiation light source being built in Beijing, Chi... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
5e5385cd-b62f-483b-ad64-4eafcda7d605 | wake effects.
INTRODUCTION
High Energy Photon Source (HEPS) is the first new-
generation synchrotron light source in China. The HEPS
accelerator consists of a linear accelerator, transport lines, a
booster,andastoragering. TheHEPSstorageringwitha
beamenergyof6GeVandanaturalemittanceoflowerthan
60pm·radisdesignedforgene... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
e2780187-fda3-41be-8dff-43371f8a9911 | ofeachbunchfromthebeampositionmonitor(BPM)and
sendthedigitizedsignalintotheprocessingelectronicsto
calculatethecorrectionsignal,whichisthenamplifiedby
the power amplifier and sent through the feedback kicker to
act on the bunch.
In the transverse feedback system of the HEPS storage
ring, the commonlyused stripline kick... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
03bb57fc-eb74-440b-9d6c-2063f011ae67 | 166.6 MHz, thereforethe transversefeedback kickerneeds
to have a bandwidth from DC to 𝑓𝑅𝐹/2 (roughly 85 MHz).
∗emailaddress: liuxy94@ihep.ac.cnConsideringthattheworkingbandwidthofstriplinekicker
is mainly decided by the length of stripline electrode, and
atoo-longelectrodeiseasytobendandheavy,alengthof
450mm is chos... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
b01cbe55-6c7f-44f8-8e3d-c4ad727ca97c | and BPM. The mentioned parameters of HEPS storage ring
arelistedinTable1,basedonwhich,theverticalinstabilityis
moreseverethanthehorizontalinstability,soweplantouse
twoverticalfeedbackkickersandonehorizontalkicker. In
thenextsection,thedesignconsiderationsofthesefeedback
kickers are introduced.
Table 1: Corresponding Pa... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
4d3265da-f097-4110-abca-b7b5a6c6854f | scribed, also the difference between the horizontal feedback
kicker (HFB kicker) and the VFB kicker.
Vertical feedback kicker The transverse feedback
kicker in the horizontal and vertical directions almost has
the same structure. Using the vertical kicker as an example, | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 0 |
420635dc-fa4a-488a-8373-fcbbefcaf0e8 | the stripline kicker mainly consists of two curved electrodes
located in the vertical plane inside a round pipe. as basi-
callyshowninFig.1. In bothends ofeachelectrode,there
isavacuumfeedthroughconnectedtotheoutside,thetwo
feedthroughsindownstreamareusedtofeedincorrection
signal, the two upstream are connected to matc... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 1 |
640a6e72-d0c3-4d34-91d3-38b640336c07 | fore we need to match 𝑍𝑜𝑑𝑑to roughly 50 Ωto reduce re-
flection. Besides,thelongitudinalbeamimpedancecanbe
expressed as in Eq. (2) [3,4],
𝑍∥=𝑔∥⋅𝑍𝑒𝑣𝑒𝑛
2[sin2(𝑘𝐿)+𝑗sin(𝑘𝐿)cos(𝑘𝐿)] (2)
where k is the wavenumber, L is the longitudinal length
of the electrodes and 𝑔∥is the longitudinal geometric factor
(f... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 1 |
716b686d-3028-46cf-9b92-74b6db2c12fd | ring) and a thickness of 2mm, the surrounding beampipe
hasaradiusof19.5mm, thestriplineelectrodeandground
separation has a coverage angle of 95 deg and 45 deg, re-
spectively. The optimized characteristic impedance 𝑍𝑜𝑑𝑑is
48Ωand𝑍𝑒𝑣𝑒𝑛is 53Ω.In order to further reduce the longitudinal beam
impedance, the stripli... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 1 |
97883199-7880-40c2-aeff-baa941286d20 | results presented in this paper, the whole structure of the
feedthrough is included.
HorizontalFeedbackKicker FortheHFBkicker,as
thestriplineelectrodesarelocatedinthehorizontaldirection
and have poor heat exchange with the outside, we need to
consider the synchrotron radiation. Therefore, the inner
radius of electrode ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 1 |
22b37f21-a1fd-4eef-a72c-004328021dce | tionparameterversusfrequencyforboththeHFBkickerand
the VFB kicker is shown in Fig. 5, which indicates the |S11|
in the working bandwidth 0 85MHz is lower than -20dB,
that is, the reflection power is lower than 1%.
Transverse Shunt Impedance
Thetransverseshuntimpedance 𝑅𝑡isanotherimportant
parameter to measure the eff... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 1 |
cd1c7bd3-9bee-4289-a058-14fcb5d665a7 | Figure 3: The 3D model of the vertical feedback kicker: a) the whole model; b) and c) show the detailed structures of
stripline electrodes and the beampipe.
Figure5: ThereflectionparametersoftheHFBkickerand
the VFB kicker.
has a minimal value of 54.4 k Ω. Combining the required
kickvoltagelistedinTable1,theHFBkickernee... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 2 |
b08635e9-815e-4b78-bdaa-8d323b663348 | distribution and the power dissipation of each part. Com-
biningwiththebeaminformation,wecanderivethepossi-ble dissipated power on the stripline electrode and then the
thermal and structural effects, which could be a judgment
criterion of a good or bad design.
Table 2: Wake Loss Factors of the Transverse Feedback
Kicke... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 2 |
1cb660f6-d558-4151-b30a-06c5351d9381 | including reflection parameter, shunt impedance, and beam-
induced wake effects are presented. These kickers are under
fabrication and will be tested and installed this year.
ACKNOWLEDGEMENT
I would like to thank Micha Dehler from PSI for many
enlightening discussions and useful suggestions.
REFERENCES
[1]“The Brief In... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA069.pdf | 2 |
8a516728-68f5-4ff9-a51c-ae9ee0e962d8 | SPIN COHERENCE AND BETATRON CHROMATICITY OF DEUTERON
BEAM IN NICA STORAGE RING
S. Kolokolchikov, International Union of Pure and Applied Physics, Geneva, Switzerland
Y. Senichev, A. Aksentyev, A. Melnikov, Institute for Nuclear Research
of the Russian Academy of Sciences, Moscow, Russia
Abstract
Thepossibilityofspincon... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 0 |
a96803ae-4db4-467d-ac0d-346362fcc7ad | arcsmustbeused. Sincesextupolessimultaneouslyaffect
thebetatronchromaticity,weconsiderthiscomplicatedcase.
QUASI-FROZEN SPIN
T-BMTequationsdescribetheevolutionof ⃗𝑆–spin-vector
overtimeinparticlerestframein ⃗𝐸,⃗𝐵fieldsinlaboratory
frame:
𝑑⃗𝑆
𝑑𝑡=⃗𝑆 ×(⃗Ω𝑀𝐷𝑀+⃗Ω𝐸𝐷𝑀),
⃗Ω𝑀𝐷𝑀=𝑞
𝑚𝛾{(𝛾𝐺 +1) ⃗𝐵⟂+(𝐺 +1) ⃗�... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 0 |
e9ac3735-05c6-4eac-b8f2-59425281f1da | «Quasi-Frozen Spin» condition for deutrons [2]. For this
needs NICA needs a modernisation to use NICA as stor-
ageringwithalternativestraightsectionsbyusingByPass
channels [3].
SPIN TUNE DECOHERENCE EFFECTS
IfwefollowT-BMTEq.(1)spin-tunesin 𝐸,𝐵fieldsare
given by the expressions:
𝑣𝐵𝑠= 𝛾𝐺,
𝑣𝐸𝑠=𝐺 +1
𝛾−𝐺𝛾.(2)... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 0 |
be427934-df36-44a9-a983-f7a01a004b50 | tances,𝜈𝑥,𝜈𝑦– tunes,𝛿0– momentum relative deviation,
𝛼0,𝛼1– two first terms of momentum compaction factor.
Equation (2) together with Eqs. (3-5) show that spin-tune
spread depends on the equilibrium energy level of the parti-
cle.
Orbit Lengthening and Betatron Chromaticity
More formal theory implies the interac... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 0 |
57d77ac0-2379-4637-b6ce-d0bc6fb89d56 | dispersionregions. Usually,inminimum/maximumofdis-
persion𝐷𝑥,𝑦and beta 𝛽𝑥,𝑦functions for the most impact.
Twiss-functions of NICA arc are regular and can be seen at
Fig.2[6]. Dispersionissuppressedwithmissingmagnets
at the edges. | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 0 |
1b20bbfe-bc7b-41eb-95cd-1e1b1ef573f4 | Figure1: Spin-tune dependance from x, y,d – coordinates forvarious optimization cases. NC– natural chromaticity(red
line);BC–zero(betatron)chromaticity(bluedottedline);SC–spincoherence(greenline);BC 𝛼–zerochromaticityand
zero𝛼1(violet line); BC 𝜂– zero chromaticity and zero 𝜂1(light blue line).
Figure2: Twiss-funct... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 1 |
6849c94d-241e-40bf-9218-83276452f33d | Ringis𝜈𝑥,𝑦= −17/−17 . Afteroptimisationwecanmonitor
spin-tuneatFig.1: redlineshowsnaturalchromaticity,blue
one–corrected. Forthiscasealsomadespintrackingduring
3×106turns for particles with different initial deviation in
𝑥,𝑦,𝑑–coordinatesandinitialspinorientation ⃗𝑆0atanangle
of 45 degrees in 𝑦-𝑧plane Fig. 3 [... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 1 |
ab3677c1-e1cf-41c6-b5cd-0c490714534c | selected in other way, just to get spin coherence.
Figure 4: Spin Tracking for particles with various initial
deviation in 𝑥,𝑦,𝑑– coordinates using 3 sextupole families
to get spin coherence. | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 1 |
2cd16d5a-e894-40fd-8c3f-c885f8d922b2 | Table 1: Main parameters fordifferent types of optimizations.
Optimization No optimization Chromaticity Spin Coherence Chromaticity + 𝛼1Chromaticity + 𝜂1
Tunes −17/−17 0/0 −13/−18 0/0 0/0
𝛼1 0.2 −0.4 −0.37⋅10−2∼ −10−12−0.85
quad𝐾𝑥 −0.16⋅10−10.55⋅10−10.27⋅10−130.55⋅10−10.56⋅10−1
quad𝐾𝑦 0.51⋅10−20.76⋅10−1−0.12⋅10−... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
dd343ab6-51e9-42f4-b6d7-229ad2c0d224 | 𝜈𝑥,𝑦= −13/ − 18 , but it is not enough for stable orbital
motion. Andforthiscase,itcanbeseenthatspincoherence
achieved – there is no dependance of coordinates/energy
(Fig. 1: green line), it can be seen also at tracking results on
Fig.4. Hereisthespin-tuneswitcheduptothe 𝜈𝑠∼ 10−7
and considered 3×106turns or∼ 3sec... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
327c3406-2a8b-4bc4-8f7d-94b60d285baa | lengthening,mustbecorrectchromaticities 𝜉𝑥,𝜉𝑦and𝛼1to
zerovalue. Itisalsopossibleusing3sextupolefamilies. But
stilldid not allowto getspin coherence. Fig.1 (violet line)
shows the non-zero spin-tune dependance from coordinates.
SameoccursifwefollowEq.(4)andsuppress 𝜂1together
withchromaticitycorrection(Fig.1). Mor... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
3af1a6e8-3a8a-44df-8b81-7e30a98b84ec | research shows that it is not possible to use 3 sextupolesfamilies in regular structure to compensate both betatron
chromaticitiesandgetspincoherence. Moreover,maximum
value of sextupole coefficient not satisfactory and can cause
non-linear instabilities.
Itisworthnotedthatregulardispersionfunctiononthe
arc did not all... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
63f40b0f-d35b-4d01-8635-24edc132e607 | DipoleMomentsinStorageRings”, Phys.Rev.Lett. ,vol.93,
no. 5, Jul. 2004. doi:1/zero.alt4.11/zero.alt43/physrevlett.93./zero.alt452/zero.alt4/zero.alt41
[2]Y.Senichev etal.,“Quasi-FrozenSpinConceptofMagneto-
Optical Structure of NICA Adapted to Study the Electric
Dipole Moment of the Deuteron and to Search for the Ax-
io... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
0d6f1c5d-ecde-4025-8a9b-9c1d79ab8f43 | “SpinTuneDecoherenceEffectsinElectro-andMagnetostatic
Structures”, in Proc. IPAC’13 , Shanghai, China, May 2013,
paper WEPEA036, pp. 2579–2581.
[5]Y.Senichev,A.Aksentyev,andA.Melnikov,“SpinChromatic-
ityofBeam: OrbitLengtheningandBetatronChromaticity”,
Phys. At. Nucl. , vol. 84, no. 12, pp. 2014–2017, Dec. 2021.
doi:1/... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA070.pdf | 2 |
e45d8164-5e9a-41ae-b28d-e642b1ad1a95 | A FEASIBILITY STUDY INTO THE QUASI-FROZEN SPIN REGIME OF
OPERATION OF THE NICA STORAGE RING
A. Aksentyev1,∗, A. Melnikov, Y. Senichev, Institute for Nuclear Research
of the Russian Academy of Sciences, Moscow, Russia
S. Kolokolchikov, International Union of Pure and Applied Physics, Geneve, Switzerland
V. Ladygin, E. M... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 0 |
f09ad7d6-0431-4319-8856-769d4aa47617 | compatiblewiththeexistingoptics;onethatwouldn’tdisrupt
thering’scapabilityforparallelexperiments. Suchamodifi-
cationisthe“Quasi-FrozenSpin”idea,realizedbyadding
transport channels, bypassing the ring’s straight sections.
Wien-filters are placed in these channels in order to com-
pensate spin-rotations caused by the ri... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 0 |
0f901ec1-bb20-4562-8d3c-4fc5fb4da778 | spin-coherence time.
THE FROZEN AND QUASI-FROZEN
LATTICES
Frozen spin and its lattice requirements
The motivation for this study is the search for the elec-
tric dipole moments (EDMs) of elementary particles. In an
acceleratorringenvironmentthemostpromisingmeasure-
ment idea, which grounds the “Frozen Spin” accelerator... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 0 |
031eba7c-9f0b-422a-a569-9d643ea4d0f4 | vectorsareinvariablyalignedatanypointalongthebeamline.
Sincethemomentumvectorrotatesintheacceleratorarcsby
means of the guiding magnetic field, the polarization vector
∗a.aksentyev@inr.rumustalsoturnthere simultaneouslyand bythesame angle.
The spin-rotation angle is related to the momentum one via
the spin tune 𝜈as in... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 0 |
c05a8b12-094c-4c1a-908f-527295f39c0e | dedicated to the experimental program is thus required.
Figure 1: A possible lattice with cylindrical Wien-filters for
the realization of the frozen spin condition.
Apartfromthisinconvenience,therearefurthermotivesto
lookforanalternative. Onemightaskoneself,whencecame
the frozen spin (FS) condition in the first place? ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 0 |
c32146ff-3e62-4e28-81d3-b7df1a31ce97 | linearizationoftheobservable 𝑃𝑉(𝑡)andalsowithrespect
tosystematicerrors(theso-called“geometricalphase”error
due to the non-commutativity of spin-rotations).
Quasi-frozen spin and the NICA collider
But what if, instead of using the integral value Θ(𝑡), one
uses the spin precession frequency 𝜔as the experimental
obs... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
3df7d62d-7039-4813-b644-6f9a575bed2d | name,“quasi-frozen”);butnow,onemightleavetheexist-
ing accelerator’s arcs untouched, only adapting the straight
sections to the task.
Now turning to the NICA collider (JINR, Dubna, Rus-
sia),originallydesignedforheavy-ionexperiments,ifitis
to be used for EDM-measurement it needs first to be turned
intoa storagering cap... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
cf2e11ab-dec7-43f5-a71a-1b945dc36153 | PREFERENCE OF THE LATTICE DESIGN
CONCEPT WITH RESPECT TO THE EDM
MEASUREMENT
Itisnotuninterestingtosummarizesomeofthegeneral
motivationsinfavorofoneortheotherlatticedesigncon-
cept.
Thetwoparametersbywhichwecategorizethelattices
in the following are : (1) the methodological principle of
EDM-measurement and (2) constuct... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
8cc91c2c-a31d-4cb2-8494-f3c0abf201af | zero instantaneous power. The FS-lattice is such a design
concept. The QFS lattice, in which the compensation is
bydesignasynchronous,wouldnotsuitsuchacategoryof
methods.
On the other hand, the FS-lattice is also suitable with
respecttothe“frequencydomain”methodvariety. So,the
FS-lattice is more versatile in terms of m... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
4fe4100c-ec70-4f30-8d08-44ef05888a29 | the EDM one [4]), it becomes even less attractive.
Tosummarize,“spacedomain”methodologyfavorsthe
FSdesign,whileconstructionalconsiderationstheQFSone.
Thelatteralsomakethe“frequencydomain”methodology
preferable,aswellas,wearguein[4],thephysicalunviability
essentially determining the “space domain” concept.
INVESTIGATED ... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
4c5de00d-11ca-4b48-b076-4bf5e5771775 | correctforbetatronandspinchromaticities. Bothofthese
propositionswereinvestigatednumerically,usingtheCOSY
Infinity code. [5]
Inthestandardformalism,thelattice’sspin-transferma-
trix is an SO(3) rotation matrix parameterized by the nor-
malized spin precession frequency, spin tune, 𝜈, and the
invariant spin axis ̄ 𝑛:�... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 1 |
a156987b-97a7-4c2d-a9af-7bebec6833bc | Figure3: Referenceparticlespintune 𝜈0dependenceonthe
EB-element’s E-field.
beam polarization; however, for EDM experiments the part
of polarization orthogonal to ̄ 𝑛is of interest, one whose
expectation value is zero – hence the significance of the
term “spin coherence time.”
The question of whether the beam’s spin c... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 2 |
d860e27d-c85a-405f-8834-76cd59fed67b | used in the simulation. Another point of concern is that
in this setup both the betatron chromaticity and the spin
chromaticity could not be simultaneously reduced. [7]
CONCLUSION
Wehaveconsideredthepossibilityofadaptingtheexisting
NICA lattice to the purpose of EDM measurement. Two
basicquestionsthatneededtobeanswered... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 2 |
b7d3421f-0bf8-40d3-9697-d004e43841c7 | impossibility of simultaneouslyreducing both the spin and
betatronchromaticities. Possiblesolutionstothisproblem
have been proposed [7]. In any case, it warrants a further
research.
(a) Sextupoles off, dispersion present.
(b) Sextupoles on, dispersion reduced.
Figure 4: Spin vector components as functions of beam
revol... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 2 |
6da8800b-06d7-4b01-b8f6-940a276955c2 | [3]S.Kolokolchikov etal.,“BypassopticsdesigninNICAstorage
ringforexperimentwithpolarizedbeamsforEDMsearch,”pre-
sented at IPAC’23, Venice, Italy, May 2023, paper MOPA072,
this conference.
[4]A.E.Aksentev,Y.V.Senichev,“Frequencydomainmethod
of the search for the electric dipole moment in a storage ring,”
J. Phys.: Conf.... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA071.pdf | 2 |
36ca8155-5024-412c-9159-25aa804157a5 | BYPASS OPTICS DESIGN IN NICA STORAGE RING FOR EXPERIMENT
WITH POLARIZED BEAMS FOR EDM SEARCH
S. Kolokolchikov, International Union of Pure and Applied Physics, Geneva, Switzerland
Y. Senichev, A. Aksentyev, A. Melnikov
Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia
E. Syresin, V. Lady... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
291e3ed2-2446-4f64-8245-212c05401204 | to use deuterons at the energy of about 240MeV. To en-
surethe«Quasi-FrozenSpin»mode,E+Belements(namely,
Wien Filters) are required as well. Such elements can be
placedinstraightsectionstocompensatethearcspinrota-
tion.
ForEDMmeasurementexperiments,itisnecessarytoop-
eratetheNICAasaStorageRing,andnotinacollidermode.
To... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
9ea4cc82-d4ec-48a5-bc78-627b9440ef39 | theuseofdeflectorswithbothanelectricandmagneticfield.
Thus, spin rotation in a magnetic field is compensated by
an electric one in one element (similarly for orbital motion).
Thus,thespinretainsitsorientationduringtheentiretime
of rotation in the ring. However, the dipoles in the NICA
main ring arcs have only the magne... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
f80c803e-adaa-4658-ac66-00e9dec600ff | andmagneticfields,whicharecalledWienFilters. Therota-
tion of the spin in the arc by a certain angle is compensatedby the corresponding rotation in the Wien Filter. Also fields
canbechosentomakezero-Lorentzforceanddonotdisturb
orbit. For this reason can be installed on straight sections.
Thus,polarimeterslocatedafterWi... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
959bca9a-982d-4156-9be8-6a3ff204a98f | ofByPasschannelsto create an alternativestraightsection,
paralleltotheoriginalone(Fig. 1). Thus,NICAcanbeused
as a Storage Ring. Such rings can carry out EDM search
experiments with polarized deuterons at QFS regime.
Experiment Parameters
An important experiment parameters are particles and its
energy.
Thelargestscatte... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
c53930ff-4375-45e3-a8dd-968bebd4a566 | Whichleadstoadeviationofthespin-vectorbyasmallangle.
For protons this expression is too large 𝜋 ⋅ 𝛾 𝐺𝑝/2 > 1.
Spin-vectorrotatesaroundthemomentum-vectorandlead
to the loss of spin stable motion.
Thesefeaturesisdecisiveinthechoiceofparticlesforthe
experiment. Inthe future,allthe proposedmagneto-optics
will be consid... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 0 |
7a3be82e-3707-4915-ac47-06bf11852e5e | BYPASS OPTICS DESIGN
DesigningByPassNICAStorageRing,thegeometryof
arcsisplannedtoremainunchanged. Sothatitispossible
to use NICA for various experiments.
In NICA ring, arc is a place with a non-zero dis-
persion. At the edges, both dispersion and its deriva-
tive suppressed to zero. Straight section has zero dis-
persi... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 1 |
026e9397-fdcc-4f9f-887f-0a8a067f5b74 | of 1 meter from the native ones, so ByPass section length
𝐿𝐵𝑃= 1m/sin𝛼 ≈ 6.4m. Schematicdiagram of ByPass
channels shown on Fig.1
Figure 1: Schematic diagram of the ByPass channels in the
existing NICA complex.
Deflector magnets distort dispersion function. Thus,
needed to use at least 2 focusing quadrupoles on ByP... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 1 |
afde9a42-1302-4d51-bc5c-94f6065bdf1c | quadrupoles(Fig.2). ThematchingofthearcwiththeBy-
Passisprovidedbythreequadrupoles(M1section). Andthe
matchingoftheByPasswithastraightsection(M2),whichis
identicalbyvirtueofsymmetry,andconsistof3quadrupoles
toensurebeta-functionperiodicity(Fig.3). Totallengthof
the whole accelerator is then 𝐿𝑎𝑐𝑐
3𝑞𝑢𝑎𝑑= 503.46 m... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 1 |
056b3946-c50c-4674-84cb-e06d22c24eb4 | 2 quadrupoles. But the whole accelerator length become
longerthanNICAallow 𝐿𝑎𝑐𝑐
5𝑞𝑢𝑎𝑑= 510.02 mFig.5shows
that maximum of 𝛽𝑦become lower at the center. Thus, this
case must be adopted to the real one.
Figure 5: Twiss-functionsforByPasswith 5 quadrupoles. | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 1 |
672d645d-ef52-41a0-83c3-6ffe85a0a8cb | Real
Figure 6: Schematicdiagram forRealByPass.
Basedontheconsideredcases,wecanfinallygetstructure
closely adopted to reality. Now, straight section is fully
regularandshorter 𝐿𝐵𝑃
𝑆𝑆= 80.71m(Fig.6). ByPassconsist
from 5 quadrupoles and deflect beam by 1.46m. But for
matching used different sections M1 and M2 to com... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 2 |
f5f36c74-b359-4d84-b47f-28fcc15f98a7 | Ion NICA 503.04 9.44/9.44 109.6
3 quad 503.46 13.8/11.8 83.97
5 quad 510.0 13.44/11.44 83.97
Real 503.5 12.8/11.8 80.7
SPIN TRACKING
Spin-tracking is shown on Fig.8 in one half of new By-
Pass NICA ring, and consist from: arc, ByPass channel,
straightsectionand2matchingsections(M1andM2). Con-
sideredverticallypolarized... | d:\Daily_ihep\Weekly Progress Report\20260425\41_IPAC'23\MOPA - Monday Poster Session_ MOPA\MOPA072.pdf | 2 |
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