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701e739e-f7e1-4498-aee7-d156def93bff | generation method for producing femtosecond coherent ra-
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[12]Y. Luet al., “Methods for enhancing the steady-state mi-
crobun... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEMC - Parallel Talk Session 1_ WEMC\WEMC3.pdf | 3 |
a873f731-8a17-453b-a16c-f45c3ddb25fa | doi:1/zero.alt4.1/zero.alt438/s41598-/zero.alt423-41118-/zero.alt4
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f853ef8d-8853-4069-b9f0-791689362602 | MODELING OF CSR A ND ITS CANCELLATION
IN DBA/CHICANE TYPE COMPRESSORS*
Fancong Zeng1, 2, Yi Jiao†, 1, 2, Weihang Liu1, 3, Cheng-Ying Tsai4
1Institute of High Energy Physics, Chines e Academy of Scien ces, Beijing, China
2University of Chinese Academ y of Sciences, Beijing, China
3Spallation Neutron Source Scie nc... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
f56370d8-3c66-4dd8-9aac-669486134738 | fect. To tackle this, we develop a new analytical model for
CSR that can describe beam transport with varying bunch
lengths, establish a practical framework for analyzing CSR
in both DBA and chicane-type compressors, and design
CSR-suppressed DBA compressors (arc-type) as well as
non-symmetric C- and S-shap ed chi... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
11dddba3-eafe-4cc0-9ff3-0cdd8fc56a18 | INTRODUCTION
The advent of accelerators and accelerator-based light
sources has revolutionized advancements in science, in-dustry, medicine, and materials research. In modern accel-
erators, electron bunch compre ssors play a pivotal role,
with wide applications in linear colliders, linacs, beam
driven plasma-wakef... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
58e3b585-82dd-4339-af91-31aeb2c80917 | pressors are the most commonly used bunch compressors in linac-based systems and ar c systems, respectively. How-
ever, due to the high peak current required for FELs, the
ability to compress an electron bunch with minimal degradation of beam quality becomes challenging because
of the effects of coherent synchrotron ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
321b5df8-6a87-4029-b62e-b5e6a6dca7aa | chicane compressors, includin g analytical, numerical, and
experimental studies [5-8]. Among them, the approach of suppressing the deleterious effects of CSR by manipulating
beam optics has sparked continuing research interest.
The optical balance method was first proposed by Doug-
las [9] and was further developed ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
fd54a147-4d10-4e4a-91cf-b31dfd4c1ebe | consistent modified CSR point-kick model that accounts for variations in bunch length. Based on this model, we es-
tablish a practical framework for analyzing CSR in both
DBA and chicane-type compressors, envisaging the poten-tial designs for a CSR-immune DBA and chicane compres-
sors.
Modified CSR Point-Kick Model ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 0 |
7e253800-241f-4246-9fc9-3413f218e76f | After a particle passes through a dipole magnet with a
bending radius 𝜌 and bending angle 𝜃 (see Fig. 1), its hor-
izontal coordinate deviation and energy deviation relative
to synchronous particle change under the influence of CSR
as follows [10]:
𝑥ୡୱ୰ൌන ఏ
𝑑𝛿ୡୱ୰ሺ𝜙ሻ
𝑑𝜙𝑅ଵ௦→௦𝑑𝜙,
𝑥ୡୱ୰ᇱൌන ఏ
𝑑𝛿ୡୱ୰ሺ𝜙... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 1 |
1363c21c-a8d2-4d73-b2f0-ba102d027107 | itial bunch length and is in the form
𝑘ൌ 0.2459ே್
ఊఙబర/య ሺ3ሻ
The resulting CSR kick after a particle passes through a
dipole magnet is given by (a more detailed analysis can be
found in Ref. [11])
𝑋ൌሺ𝑥
𝑥ᇱሻ
ൌሺ𝜌ସ/ଷ𝑘ሾ𝑔௫𝜃cos ሺ𝜃/2ሻ−2ሺ𝑔௫cos ሺ𝜃/2ሻଶ𝑔௫sin ሺ𝜃/2ሻଶሻsin ሺ𝜃/2ሻሿ
sin ሺ𝜃/2ሻሾ2𝛿𝜌ଵ/ଷ𝑘ሺ𝑔௫... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 1 |
e286b5aa-33b5-4f70-a5c4-b7205eccc84a | 𝜃. ሺ5ሻ
They reflect the impact of th e dipole on the dispersion
function. By setting all correction functions are equal to 1, the resulting CSR kick after a particle passes through a di-
pole magnet can be reduced to the constant-length point-
kick model:
𝑋
ൌቆ𝑥
𝑥ᇱቇൌ൮𝜌ସ
ଷ𝑘ቂ𝜃 cosቀ𝜃
2ቁ−2s i nቀ𝜃
2ቁቃ
sinቀ𝜃
... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 1 |
9ea34a39-a34c-469f-afda-ad2ecd579294 | Due to the arbitrariness of the parameters 𝑎 and 𝑏 in
Eq. (5), the correction functions in Eq. (4) generally cannot
be expressed in a simple analytical form. However, there
are two special cases (see Fig. 2) where the dispersion functions can be well determined. We first consider a di-
pole with zero entrance di... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 1 |
7403a870-f062-40f4-bc88-9e037ea486ac | Another special case is when both the dispersion and dis-
persion gradient at the dipole exit are zero (e.g., the last
dipole in a multi-dipole achromat system). In this case,
𝑎ൌ 3 and 𝑏ൌ− 3 . The corresponding correction func-
tions can be expressed analytically as
𝑔௫ሺሾ3,−3ሿ,𝜉ሻൌ3ሺ1𝜉ሻଵ
ଷ−1
𝜉ሺ1𝜉ሻଵ
ଷ,
𝑔௫ሺ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 2 |
f538117c-97fb-4e55-a95c-4cfb915f4caa | As shown in Fig. 3, the discrepancy between the con-
stant−𝜎௭ model and the modified model is notable, empha-
sizing the importance of accounting for the bunch length
variation within the dipole. The numerical corrections and
the modified model demonstr ate excellent agreement for 𝐶
up to 40, with a relative discr... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 2 |
2c649761-2262-4545-bfac-a5f234a77bba | four bends are not subject to a specific constraint.
We derive the analytical expressions of net CSR kick at
the chicane exit and further the ss-CSR cancelation condi-
tions using a modified CSR-kick model (see Ref. [13]).
Figure 4: Schematic of the point-kick analysis of the CSR
effects.
By setting 𝐿ൌ0 and as... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 2 |
76f10608-166c-4da6-9813-7427c86a27b6 | CONCLUSION
We have proposed a self-consistent modified CSR point-
kick model that accounts for va riations in bunch length.
Then we presented a solvable model of the CSR effects in
a generic four-bend chicane and DBA, which provides us
insights on CSR compensation during beam compression. The design of the CSR-im ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 2 |
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[3] Y... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 2 |
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[8] C. Zhang, Y. Jiao, and C.Y. Tsai, “Quasi-isochronous triple
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doi:10.1103/PhysRevAccelBeams.24.060701 [9] D. Douglas, “Supp... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 3 |
d4f80079-f502-4e73-a623-2711a599bdb9 | tron radiation point-kick model with self-consistent con sid-
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[12] C. Zhang, Y . Jiao, W. Liu, and C.Y . Tsai, “Suppression of
the coherent synchrotron radiation induced emittance growth i... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WENC - Parallel Talk Session 1_ WENC\WENC5.pdf | 3 |
24dfcdea-d3ee-4bb5-80da-9a3f9d8b383e | BEAM EXTRACTION AND DARK CURRENT STUDY OF A
C-BAND RF PHOTO GUN
Xingguang Liu∗, Shimin Jiang, Shengjin Liu, Junyu Zhu, Hui Zhang, Xiao Li
Institute of High Energy Physics, Beijing, China
Abstract
Wereportonbeamextractionandpreliminarydarkcur-
rent studies conducted on a 3.6-cell C-band radio-frequency
(RF)photocathodeg... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 0 |
7567863d-7f38-4125-84c4-629483c62748 | afterthebeamtestrevealeddischargedamageonthecath-
ode surface disk, particularly around the center area. Clean-
ingmethodcomparisons wereconducted,with ’snowflake’
cleaningshowingnodetrimentaleffectsonsurfacerough-
ness. This work represents the first reported beam test for a
C-band RF photocathode gun.
INTRODUCTION
Ne... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 0 |
951f311f-3af9-4715-9e21-bdf0e3b6f937 | ∗liuxg@ihep.ac.cncanworkat 180MV/m inhighpowertest,whilea2.6-cell
gunatINFN/PSI[2]havebeentestedat 160MV/m atavery
lowbreak-downrate. Exceptforthese standing-wavestruc-
tures,travelling-wavestructureshavealsobeendesignedand
tested recently at PSI [3]. We began to develop a 3.6-cell
C-band RF gun at IHEP-Dongguan since ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 0 |
cada8fce-ee54-45b9-b567-d916471d6e72 | the 3.6-cell RF photo gun is:
2021.9: initial proposal
2022.1: project start
2022.4: external review
2022.12: prototype Gun-0
2023.4: prototype Gun-1 cold test
2024.7: high power test
2024.10: installation
2024.12: Beam test
2025.4: prototype Gun-2 cold test
Wehaveaninitialprototype(Gun-0)toverifythefabri-
cation proce... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 0 |
8951871d-fef1-46a3-aae5-1a307ffcd2b9 | Figure2:Prototypesforthe3.6-cellRFphotogun(Gun-0,
Gun-1, Gun-2 from above.
Afterthe beamtest,another prototypewith bettercleaning
method have been prepared for new beam test. In this paper,
wefocusonthebeamtestanddarkcurrentstudiesofGun-1.
TheRFdesignandinitialtestresultsforGun-1canbefound
at Ref. [6]. Photos of three ... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 1 |
432dfd4f-9dcb-444e-a95d-de695a7744d7 | Figure3:Dark currentmeasurement with theFaradayCup
(FC).
Figure4:Dark currentmeasurement with theFaradayCup
(FC).
tion to reproduce the same beam energy at various phase
and gradient. It shows that the maximum beam energy in
this round of testis close to 7MeV, corresponding to a sur-
face graident of about 140MV/m . At... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 1 |
bad58dc3-79f2-4a96-a512-054e6aba04e0 | suffersfromthemostseriousdischargedamage,asshownin
Fig. 4. It has been designed to be replaceable, so it could be
inspectedwithsurfaceanalysis.Thewhitedotsaredischarge
points where the dark current charges are extracted. With
eye observation one can see that the discharge tracks are
moreseriousinthecenterareaandgradual... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 1 |
7c537841-ee34-4786-85cf-0be06ac8d1d1 | Figure5:Dark currentmeasurement withthe FaradayCup
(FC).
Figure6:Dark currentmeasurement withthe FaradayCup
(FC).
Figure7:BeamextractionmeasuredwithFCandthedark
current.
Another important observation is the serious discharge
happened in the holes around the surface disk, which are
designed to support a better vacuum in... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
7f42ec71-f7d4-497b-b4a6-f961facdf737 | Also,thedarkcurrenthavealargerbeamsizecomparedwith
photoinducedbeam,asshowninFig.7.Therefore,astothe
darkcurrent,whathasbeenmeasuredattheFCcannotbe
fullyaccountedtothesurfaceemission.Inthissimulation,
cathode surface are assumed to be a emission surface while
thedischargecurrentdensityisassumedaradicaldistribu-
tionfol... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
d6bba821-2b70-4779-adfd-1bb505f07545 | main issue in such a structure.
Cleaning Method
To study how different cleaning methods will affect the
roughness of the cathode disk surface, four typical ways
ofcleaningarecomparedalongwiththesurfacecheck:(1)
”Ethanol + fine fabric” by hand; (2)”Ultra sonic + Deion-
izedWater/Ethanol”whichiscommoninsuperconducting
st... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
82baeb3d-b01f-4410-aa09-e7259bd8e724 | darkcurrentwasobservedathighfields.Surfaceanalysisaf-
terthebeamtestshowsthatseriousdischargehappensatthe
cathode surface disk. Surface cleaning method comparison
showsthat‘snowflake’cleaningwillnotaffectthesurface
roughness.Somepreliminarysimulationstudiesonthedark
current have been done while more detailed experiment... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
acd3de60-6aaa-4e7a-8351-b22947cc8802 | standforhighbrightnessC-bandphotogunsatPSI”,in Proc.
IPAC’24, Nashville, TN, May 2024, pp. 2133-2136.
doi:1/zero.alt4.18429/JACoW-IPAC2/zero.alt424-WEPC69
[3]T.Lucasetal.,“TowardabrightnessupgradetotheSwissFEL:
Ahighgradienttraveling-waveRFphotogun”, Phys.Rev.Accel.
Beams, vol. 26, p. 103401, 2023.
doi:1/zero.alt4.11/z... | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
9157d55b-de36-4a41-b4a9-f9113107c033 | [6]S. Liuet al., “RF design of C-band photocathode electron gun
for Southern Advanced Photon Source”, High Power Laser
Part. Beams , vol. 37, p. 014005, 2025.
doi:1/zero.alt4.11884/HPLPB2/zero.alt42537.24/zero.alt4195 | d:\Daily_ihep\Weekly Progress Report\20260425\110_SAP2025\WEXC - Parallel Talk Session 2_ WEXC\WEXC6.pdf | 2 |
7d641858-fd99-44f4-acd9-17ad1ca96606 | MEASUREMENT OF NANOAMPERE BEAM INTENSITIES AT FAIR*
T. Sieber†, H. Braeuning, M. Schwickert, GSI, Darmstadt, Germany
L. Crescimbeni1, F. Schmidl, Friedrich -Schiller -University Jena, Jena, Germany
T. Stoehlker1,2, V . Tympel1, Helmholtz Institute Jena, Jena, Germany
R. Stolz3, V . Zakosarenko4, Leibniz IPHT, Jena... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
c87dea75-635b-46f7-8ef1-31e368b23b3d | measures the intensity of particle beams via their azimuthal
magnetic field. The superior performance of the CCC
hereby derives from the high s ensitivity of a SQUID
(Superconducting Quantum Interference Device), which
detects the current in the CCC pickup coil . This enables for
a current resolution in the nA r... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
87979d54-ad52-46f1-abb4-177023b00f0d | beams from SIS18. Among the CCC types, which have
been investigated, the 'Dual Core' (DCCC) version showed the best performance with respect to bandwidth and current
resolution. The DCCC and its cryostat therefore mark a provisional closure of CCC development for FAIR.
In this contribution we present the latest res... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
9abee0a9-d225-4eef-9146-092fc28ff489 | FAIR ), this prototype had a numbe r of severe
disadvantages , which m ade it unsuitable for practical and
longterm operation in the HEBT and excluded the
operation in storage rings. The necessary development
work to match the FAIR requirements covered the full spectrum of cryogenic , vacuum, mechanical propert... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
c1d53afd-f68c-4abf-bb8a-bd1f6bd2cd29 | CCCs in accelerators. The d etails of this work are
described in [2-4 ]. Latest achievements were spill
measurements with a ‘classical ’ radial Niobium CCC as
well as with a Pb Dual Core DCCC at GSI SIS18 , advanced
filtering of periodic disturban ce and - last not least - the
stand -alone operation of the... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
9d75bf26-332d-45dc-8a93-394706c88a55 | Current to an internal pickup loop, which is basically a one -
winding coil around a high permeability ring core as flux
concentrator. The ring core is used in the ‘ classical ’ CCC
as shown in Fig. 1 to provide an efficient coupling of the
beam magnetic field to the SQUID circuit. In later versions it was omitted... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 0 |
d56ec0af-6200-4c12-998e-f7e0aa6b7a6f | (DCCC). The arrangement is (like in an ACCT) basically a
transformer with the parti cle beam as primary winding and
the pickup coil as the secondary winding.
The signal from the pickup coil is fed via an impedance
matching transformer to the DC SQUID current sensor. A
second coil is added to apply a calibration ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
5a62da7b-97b9-4bd2-b8be-5b296dcb3751 | resolution can be in the order of µ Φ0 (Φ0 = magnetic flux
quantum).
The current resolution of the CCC is therefore very much
dependent on the stability of the SQUID flux/voltage
curve. Another important aspect of the system is its slew rate limitation (min. rise time at a given current), which
derives primarily ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
f0c23494-1ece-4ded-bff4-f99b00fa1615 | Φ
0 = h/2e = 2.06 ×10-15 Tm2.
AXIAL SHIELDING GEOM ETRY
In the course of CCC optimization and redesigning i t
was proposed to build a CCC without toroidal core, using
a shieldin g with axial meander geometry [6], consequently
the device is called ‘coreless ’ or ‘axial ’ CCC. This
shielding/pickup design provide ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
b965e2dc-d9c4-4aab-be94-8aa9e26a32cc | weight. Furthermore, the axial geometry allows for lead as
shielding material (instead of niobium) , which reduces the
costs by at least a factor 5 .
The coreless axial CCC prototype could not be
successfully operated in the FAIR cryostat d ue to its
sensitivity to external noise and in general its weak
co... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
80ca9f56-a154-4b8e-a61e-569c9dbed35e | which achieved - besides excellent magnetic shielding - a
current resolution equal or better than the c lassical , radial
CCC. This version is called the ‘dual core ’ or DCCC.
Figure 3 shows the three mentioned varieties at one glance.
Figure 4 shows the noise figures of an axial CCC
prototype, the ‘ clas... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
a62c749c-7e16-4e81-b304-e08f303aae68 | 150 mm/250 mm).
Figure 4: Noise spectra measured at the FAIR CCC- XD
(blue), the GSI pro totype from [ 1] (red) and one of the first
prototypes of the axial CCC (black) .
FAIR CCC -XD STORAGE
RING OPERATION
The CCC- XD, a classical CCC version, in combination
with its specially designed cryostat [ 9], was ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 1 |
10ea2912-57a1-4f12-9703-52b5dd26d38f | the toroidal core. Additionally , a more efficient magnetic
shielding to suppress the disturbing influence of nearby
dipole magnets seemed desirable as well as a hi gher slew
rate to cope with fast pulses . Despite its drawbacks, the
prototype of the CCC -XD was tested successfully in
CRYRING@ESR, showing with ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 2 |
f1eafbf0-9d88-4154-acf7-ea373a0aad04 | Gain Bandwidth Product of the SQUID electronics [ 10].
While the results o f the CCC- XD operation in
CRYRING were promising and not too far fr om the current
resolution achieved in the laboratory [ 3], a significant
reduction of the SQUID performance was observed when
moving to the accelerator environment. M... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 2 |
10d342e2-e488-4a36-8ea0-ce632dee30bd | imposed by the environment. We concluded that t he
presence of static or dynamic magnetic fields during
cooldown were responsible for th is effect .
The main perturbation of the system is created by the
periodic He compression and expansion inside the attached
pulse tube cryocooler (re-liquefier) at a fixed... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 2 |
af7cb7b9-a148-4c52-a9de-2c346cca519a | is fluctuating and the exact shape of the resulting sig nal at
the CCC depends on the system state (e.g. remaining liquid
helium level). This makes it difficult to use background
measurements to directly subtract th e 1.4 Hz noise source.
Consequently , a digital FFT -based band -block filter was
used to elimin... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 2 |
e629f752-5562-4c69-a227-190ebfd11506 | of ~23 nA , following the dipole ramp (see Fig. 7). Since
the ramp of the dipole is deterministic, the response of the
CCC can be measured beforehand and then be subtract ed
from the beam . The blue line in Fig. 7 shows the CCC
signal during a background measurement after the
elimination of the dipole using t... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 2 |
8c03f5bb-9895-45af-8360-6c7942d466d8 | Figure 8: Stored low intensity 2D+ beam in CRYRING.
DCCC SPILL MEASUREMENTS
Figure 9 shows the comparison of current noise densities
of the coreless axial CCC and the DCCC (to be compared
with Fig. 4) . The DCCC noise is on average one order of
magnitude lower , similar to the FAIR CCC- XD, whereby
the dual ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 3 |
00a9b2d6-e071-4abf-8434-bdbf92717846 | experimental cave at SIS18 synchrotron. In a first
campaign we used a 400 MeV/u Erbium 57+ beam with
~5*108 particles per spill and later a 400 MeV/u Ar 18+
beam with ~2*109 particles. The spills had nominal lengths
between 100 ms and 1 s. At low Erbium intensity short
spills were used to reach usable intensities ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 3 |
635e5589-d8df-4af9-9f10-37fa2bced357 | driven extraction. A periodic signal is superimposed to the steering voltage of the quadrupole, which drives the
particles to betatron resonance. Due to the “wobbling ” the
effect of the power supply noise is reduced, which results
in a m ore homogeneous spill structure and therefore higher
detector efficiency at p... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 3 |
73aed88d-7108-4f5f-bf48-734242610819 | time more stable toward s fast current changes (slew rate
DCCC = 0.4 µA/µs; slew rate CCC- xD = 0.16 µA/µs). The
reason for this behavior lies in the resonant properties of
the composite detector system (shielding, pickup,
matching and SQUID). Figure 10 shows the resonances of
the two systems, which are in both... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 3 |
595ff9ea-01f7-4f18-855e-ce34771c0b5a | to the damping resistor (2.2 Ohm) is visible in the CCC- xD
curves.
Concerning mechanical disturbances, Fig . 12 shows the
noise contributions in the range 1 to 100 Hz. As said before,
the ma in source of periodic mechanical noise is the 1.4 Hz
oscillation from the liquefier and harmonics . Other noise | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 3 |
0949d526-92d5-4e72-a205-edf0ec7d3675 | contributions are pumps as well as mechanical eigenmodes
of the cryostat itself. Since the ramping/slow extraction
process is in the order of seconds, the data can digitally be
filtered offline by simple subtraction of the disturbing fre-
quencies from the FFT spectra. The spill measurement ap-
pears in real -time, ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 4 |
efd0f1e9-fa07-43ea-aea0-18522d60b8b5 | rate within 1 %. The general noise floor was around 5 nA.
More sophisticated filtering approaches are currently under development. The strategy is to use the differences be-
tween the noise signals of the two SQUIDs to enable algo-
rithmic suppression , based on summation, correlation anal-
ysis or adaptive filter... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 4 |
7e488677-757b-4daa-bfb8-a942da2ca90d | accessibility for ma intenance and repair work . The outer
dimensions of the isolation vacuum vessel are
1.2 m x 0.8 m x 0.8 m. It consists of a stainless -steel frame,
covered by aluminum windows, which enable for access to
all inner components. Figure 14 shows a 3D model.
Figure 14: FAIR CCC cryostat with C... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 4 |
be9038a9-7e07-414c-b340-defc153f1dda | result and suff icient for beamtime periods at FAIR, we
want to avoid any intervention in the tunnels ( besides
unavoidable maintenance), therefore further investigations
are necessary to identify loss mechanisms in the He circuit. Nonetheless it could be demonstrated that our combination
of cryostat and liquefi... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 4 |
986289de-20c4-41bc-89ab-292fff7f2d73 | filters shows already good results, more sophisticated
filtering will be implemented in the CCC FESA class.
Our cryostat in connection with a Cryomech liquefier
has recently achieved 6 months of continuous operation,
currently tests are performed to find the reason for (even
though small) He losses. | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 4 |
dbeefb8e-c735-437f-b0ab-c05add36b21f | REFERENCES
[1] A. Peters et al., “A Cryogenic Current Comparator for the
absolute Measurement of nA Beams”, AIP Conf. Proc . 451
pp.163-180, 1998.
[2] F. Kurian, “Cryogenic Current Comparators for precise Ion
Beam Current Measurements”, PhD thesis, University of
Frankfurt, Germany, 2015 .
[3] D. Haider , “Pre... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 5 |
e438ac3f-cc11-4183-91a7-6292b3f90123 | genics, vol. 16, no. 10, pp. 601– 605, 1976.
[6] V. Zakosarenko et al., “Coreless SQUID-based cryogenic
current comparator for non-destructive intensity diagnostics
of charged particle beams”, Supercond. Sci. Technol., vol.
32, Dec. 2018, pp. 014002.
doi: 10.1088/1361- 6668/aaf206
[7] L. Crescimbeni et al.... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 5 |
49f4cfaf-851b-451b-89a4-936bab50ab91 | doi:10.18429/JACoW- IBIC2016- WEPG40
[10] Magnicon, http://www.magnicon.com
[11] P. J. Niedermayer, R. Singh, and R. Geißler, “Software -De-
fined Radio Based Feedback System for Beam Spill Control
in Particle Accelerators”, in Proc. GRCon23, 2023, Tempe, Arizona, USA,
https://pubs.gnuradio.org/in-
dex.php/grcon/ ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOBC01.pdf | 5 |
20023b8e-4852-4df6-bf37-e86b9ef158fd | POWER DEPOSITION STUDIES FOR THE
FCC-ee HALO COLLIMATION SYSTEM
S. Marin∗, A,Lechner,R. Bruce,G. Broggi,A. Perillo Marcone,
M. Calviani,M. Widorski, G.Lavezzari
European OrganizationforNuclear Research,CERN, Geneva,Switzerland
Abstract
The Future Circular Collider (FCC-ee) at CERN requires
abetatronandmomentumcollimati... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
dd9f6f45-0a4c-4789-81fb-3782f5752269 | whichinterceptsecondaryparticlesfromthehalocollima-
tors and reduce the energy leakage to the environment. A
first optimization of the shower absorber configuration is
presented,consideringdifferentabsorberpositionsandab-
sorberlengths. Wedemonstratethatthepowerabsorptionof
thebetatroncollimationsystemcanbeincreasedfro... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
dcffb615-0a2d-4e22-ab84-3c158b71d54f | radiationpoweriskeptconstantat 50MW/beam. Atthe 𝑍-
pole,thestoredbeamenergyisthehighestandreachesabout
17.5MJperbeam,whichissufficienttodamagethemachine
if the beam is lost in an uncontrolled way. To protect equip-
ment and detectors in case of accidental beam losses and to
reduce the background in the experiments, a ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
a102f3a9-4c9a-413e-9fef-e187ee8db523 | production of neutrons in photo-nuclear interactions. The
purpose of this study is to quantify the radiation leakage
fromthecollimationsystemandlimittheresultingradiation
effects by adding dedicated shower absorbers, which can
enhance the overall energy absorption of the system. In
∗stefano.marin@cern.chaddition, we qu... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
1b95971d-c3f0-4663-b678-2461222dd520 | arestillindevelopment[1];weuselatticeversionv23and
thebeamparametersfromthefinalFCCFeasibilityStudy
Report[5]. Simulatingthepositronbeamonly,weassumea
bunchintensityof 2.16×1011positrons,and11,200bunches
per beam. We assume a beam halo-loss beam lifetime of
5minandabeamtop-upoccurringaftereachlifetimehas
elapsed, resul... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
c52cc91d-183e-4da3-8338-a1bbfc7eb913 | TCP.H 6.526 46.17 TCS.H2 6.914 429.07
TCS.H1 4.965 194.43 TCS.V2 2.931 622.78
Thegeometryofthesimulationconsistsofaconcretetun-
nelof5.5minner-borediameter,two 6cmdiametervacuum
chambers,whosecentersareseparatedby 35cm,andwhose
copperwallis 2mmthick. Inthecollimationlayout,thetwo
primary collimators, first vertical the... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
1e1ba0c3-009c-450f-9434-d367412d68af | Theabsorberiscoveredbyaframe,asupportstructureonthe
sidesnotfacingthebeamenvelopingtheentireabsorberjaw,
made of TZM, a dense ( 10.22g/cm3) alloy of molybdenum
with0.08%titanium and 0.5%zirconium. The design of
the secondary collimators (TCS) isidentical to the primary | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 0 |
a302a1ef-440a-4050-b8c1-2ab852ef8f57 | Figure 1: FLUKA geometry model of the betatron cleaning
systemincludingprimaryandsecondarycollimators,aswell
as showerabsorbers.
ones, with the exceptionthat the absorber is 30cmin length
and it is entirely made of TZM, both absorber and frame.
Thegapsofthe secondary collimators, 12and75𝜎inthe
𝑥and𝑦planes, respectiv... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
a0a4aabb-4f4c-477b-a748-6e4f0eb4ee74 | the showerabsorbers is that they may not interfere with the
collimationhierarchy. Thejawgapisselectedtobelarger
than the secondary collimator gap, 15and91𝜎in𝑥and
𝑦, respectively. Because the beam Twiss parameters vary
in the region where the shower absorbers are placed, the
half-gapofthejawsvarybetween 6.2and8.8mmin... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
eeedcaed-9722-45cf-a84d-6f75685fe45c | sample impacts on the upper jaw of the vertical and right
jaw ofthe horizontalprimary collimators.
EFFECT OFSHOWERABSORBERS
The first row of Table 2 summarizes the power loss distri-
bution along the beamline. In the environment, we account
for everything that is not included in the other categories,
notablyincludingth... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
025f37ff-70bc-4f0a-9204-08f14d7abbf3 | mize the power absorbed by the environment by inserting
shower absorbers.
The optimal configuration of shower absorbers is deter-
mined using a Bayesian optimization of parameters: the
orientationandpositionof 𝑛showerabsorbersisanalyzed.
Sincewelackacostfunctionforaddingadditionalshower
absorbers, 𝑛is used as a contr... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
359da533-63c2-4e61-a8b3-eaf276856fda | ofthepowerleakingtotheenvironmentlevelsoff,thuswith
a lengthidentical to thesecondarycollimator.
The optimization procedure indicates that two shower ab-
sorbers,30cmin length, with the first placed 20mfrom the
primary collimators, and the second 20mafter the first, can
significantly reduce power leakage to the environ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
639f29c5-5a89-4169-b371-0032518171de | isanorderofmagnitudelowerinthiswork;thepowerab-
sorbedintheenvironmentissimilar,intheabsenceofshower
absorbers. Thus,usingshowerabsorberscansignificantly
improve ontheLHC performance.
We present in Fig. 3 the linear power deposition along
the beamline. The figure shows that the most prominent
effect of shower absorbers... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 1 |
11068019-8e9f-41df-8ca7-d283a2ecc76c | 020406080100120020406080100120
SeparationTCP -SA(m)SeparationSA-SA (m)Powerabsorbedinenvironment (kW)
6.93 8.19 9.4510.7111.9713.2314.49
Figure 2: Optimization landscape of power deposition to
environment for a configuration with two shower absorbers
(SA), as a function of the distance of the first SA to the
primary co... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 2 |
b3953c77-28ce-4929-887d-6ec5f3181267 | beam loss mechanisms, surface imperfections, and beam
dynamics. We studied the dependence of power deposition
as afunction of theimpact parameter,and showthe results
in Fig. 4. With increasing depth of the interactions in the
primarycollimator,weobservealargerelativeincreasein
the power absorbed by the impacted jaw; ho... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 2 |
03fcaf25-db38-4ba0-a210-277eebfb9a63 | impacts. Broader showers are lost on the beam pipe and sur-
roundingequipmentearlier,beforereachingthesecondary
collimators.
Whilethefocusoftheoptimizationprocessistominimize
thepowerabsorbedintheenvironment,weseefromTable2
that a significant portion of the power is absorbed by the
secondarycollimators,withthemajorityg... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 2 |
2c318f96-d223-4fec-a3bd-80df70e7bd26 | Theaverageisperformedonanarrow 4mmslicearoundthe
region of highest energy deposition. Two optimized shower
absorbers areincluded in themodel.
one,eveninthepresenceofshowerabsorbers. Thepower
absorbedbysecondarycollimatorscouldposeachallenge
for the device lifetime. We present in Fig. 5 a horizontal
slice of averagepowe... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 2 |
b1f78178-d405-49b0-a5b8-88614e226074 | still indicate that, when unmitigated, almost half of the halo
power-losses are not stopped by the primary and secondary
collimators,butareratherabsorbedbythesurrounding,in-
cluding vacuum chambers, tunnel walls, or the surrounding
earth. However, the use of shower absorbers, when strategi-
callypositioned,cansignifica... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 2 |
341158c0-ff4a-46a5-a30b-de714cc9564b | REFERENCES
[1]A.Abada etal.,“FCC-ee: TheLeptonCollider”, Eur.Phys.
J. Spec. Top., vol. 228, pp. 261–623, 2019.
doi:1/zero.alt4.114/zero.alt4/epjst/e2/zero.alt419-9/zero.alt4/zero.alt4/zero.alt445-4
[2]M. Hofer et al., “Design of a Collimation Section for the
FCC-ee”,in Proc.IPAC’22,Bangkok,Thailand,Jun.2022,
pp. 1722–1... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 3 |
42d9726a-7ae2-431a-9f0e-8a16dd0189d8 | [5]M.Benedikt etal.,“FutureCircularColliderFeasibilityStudy
Report Volume 2: Accelerators, technical infrastructure and
safety”,CERN, CERN-FCC-ACC-2025-0004, 2025.
doi:1/zero.alt4.17181/CERN.EBAY.7W4X[6]FLUKA Official Website, https://fluka.cern , [Ac-
cessed: 20-Mar-2025].
[7]C. Ahdida et al., “New Capabilities of the... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 3 |
68f3bd2b-5bfd-406c-bfb5-885e67ad4550 | publication/299839564_FLAIR_A_POWERFUL_BUT_
USER_FRIENDLY_GRAPHICAL_INTERFACE_FOR_FLUKA
[10]E. Skordis, R. Bruce, F. Cerutti, A. Ferrari, P.G. Ortega, P.
D. Hermes, A. Lechner, A. Mereghetti, S. Redaelli, and V.
Vlachoudis,“ImpactofBeamLossesintheLHCCollimation
Regions”,in Proc.IPAC’15,Richmond,VA,USA,May2015,
pp. 2116... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\MOPM069.pdf | 3 |
8694a771-bcb3-48dc-aa7e-a22a075b8810 | BEA M DYNAMICS IN LANSCE ACCELERATOR FACILITY WITH
LOWER ENERGY *
Y. K. Batygin†, E. Henestroza, S. S. Kurennoy , LANL, Los Alamos, NM, USA
Abstract
In operation of the LANSCE accelerator facility, occa-
sionally it is required to provide beam at a lower beam en-
ergy than the nominal energy of 800 MeV . In this ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
9ea3859b-ebc1-4d55-8615-576f0b75d26b | 800 MeV assumes elimination of cross -terms in the beam
6D sigma -matrix at the point of injection . However, these
terms are amplified when a 700-MeV beam is injected.
Comparison of beam dynamics with nominal and lower en-
ergy operation is presented.
INTR ODUCTION
Los Alamos Neutron Science Center (LANSCE) acc... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
52538679-125b-49d6-9c01-1e87382bcd07 | Walton type generator and an ion source to produce either positively charged protons (H
+) or negatively charged hy-
drogen ions (H-) with a final energy of 750 keV . Two inde-
pendent be amlines deliver H+ and H- beams, merging at the
entrance of a 201.25 MHz Drift Tube Linac (DTL). The
DTL performs acceleration up ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
eb8d036e-b9a1-46d2-9ca2-37e8d6dbce70 | Facility (pRad) , and Ultra -Cold Neutron Facility (UCN).
The accelerator operates at a 120 Hz repetition rate with
625 μs pulse length. Parameters of all beams are presented
in Table 1.
Within operation, sporadically it is necessary to deliver
beam s to experimental targets with lower energy. In this
paper,... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
6c96bca5-bd37-4573-8994-c93d45167d79 | LINEAR ACCELERATOR
LANSCE 805 MHz Side -Coupled Linac (CCL), accel-
erates particles from 100 MeV to 800 MeV . The CCL con-
sists of 104 tanks, which are grouped into 44 accelerating
modules (modules 5 -48). Modules 5- 12 contain 4 acceler-
ating tanks each, while modules 13 -48 contain 2 tanks
each. Every tank co... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
c942380b-ee03-4bf2-bbf3-c18836e9b8ee | of linac. The CCL linac has a length ~ 700 m with an aver-
age r eal estate gradient of 𝑑𝑑𝑑𝑑/𝑑𝑑𝑑𝑑 = 1 MeV/m , and average
accelerating field 𝐸𝐸 = 1.15 MV/m, providing acceleration
with the synchronous phase 𝜑𝜑𝑠𝑠= -30o. The transverse CCL
normalized acceptance is changing from 𝜀𝜀𝑐𝑐ℎ (100 MeV) =
_... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 0 |
a7b0ee6a-63d9-4958-b861-80a673ef3e35 | 1.75 π cm mrad at the beginning to 𝜀𝜀𝑐𝑐ℎ (800 MeV) =
3.5 π cm mrad at the end of machine [2]. The transverse
matched Twiss parameters at the entrance to the first CCL
tank are 𝛼𝛼𝑥𝑥=1.228, 𝛽𝛽𝑥𝑥=5.54 m, 𝛼𝛼𝑦𝑦=0.335, 𝛽𝛽𝑦𝑦=3.24 m.
The longitudinal normalized acceptance is changing
from 𝜀𝜀𝑎𝑎�... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 1 |
243ee3eb-b24d-45e4-8be5-8558363f7e61 | and lower 700 MeV beam energy were performed with PIC
code B EAMPATH [3]. The beam in both cases was se-
lected to be matched with the CCL linac at the initial en-
ergy of 100 MeV . The operation regime of lower energy of
700 MeV assumed that the last sector of LANSCE linac,
which contains 6 accelerating modules... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 1 |
79fdb585-7794-416f-a0e7-9e15f9b0241c | tances (both transverse and longitudinal) are almost the
same, while the transverse Twiss parameters are changing
insignificantly. The most s ubstantial change is the longitu-
dinal beam size at the end of linac, which is transformed from 10
o at 800 MeV to 80o at 750 MeV in 805 MHz scale
due to long drift of 70 0... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 1 |
e8b22315-a222-4edb-a426-f75f4cb12416 | structure s, is distributed between four high-energy targets.
The Line D North (LDN) beamline bends the beam to the
south end of the accelerator facility . After Line D North ,
the H- beam is bent by the pulsed kicker magnet RIKI to-
ward the Proton Storage Ring Injection (RI) beamline. Un-
affected part of ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 1 |
96c834db-4773-4ca0-bd42-b5fb22afe0c7 | ON, (blue) modules 5 -42 ON, modules 43 -48 OFF.
Figure 3: Longitudinal beam phase space after linac: (a)
800 MeV, (b) 700 MeV.
Table 2: Transverse Twiss Parameters a nd R MS Normal-
ized Beam Emittances ( π mm mrad) after Linac
Energy
(MeV) 𝜶𝜶𝒙𝒙 𝜷𝜷𝒙𝒙 𝜶𝜶𝒚𝒚 𝜷𝜷𝒚𝒚 𝜺𝜺𝒙𝒙_𝒓𝒓𝒓𝒓𝒓𝒓
𝜺𝜺... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 1 |
f033d43d-ba37-4f1f-b79e-27d1f1d0afa0 | Simulations of beam dynamics in a LDN/RI high -energy
beamline for nominal 800 MeV and lower 700 MeV beam
energy were performed with the Elegant code [4] (see
Figs. 5 and 6). In case of 700 MeV beam transport, the val-
ues of fields in bending magnets and that in quadrupoles were scaled proportional to particle mom... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 2 |
db17bef5-e0c8-4cbe-aa01-c7f394606f80 | noticeable (see Fig . 6). The largest coupling at the foil po-
sition is between the horizontal coordinate and the bunch
length .
BEAM ACCUMULATION IN PROTON
STORAGE RING
The LANSCE Proton Storage Ring is the 90 .2-m cir-
cumference storage ring, accumulating ~ 5 μ C of protons
within 625 μs and extracting it to... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 2 |
cdb016b2-47ed-4791-b866-7cd7221cf5d3 | Lujan Center. The 68 -ns gap allows for the extraction and
injection of the beam.
Important aspect in changing of operation regime of Pro-
ton Storage Ring is prevention of elevated beam loss . Typ-
ical average beam losses in PSR are at the level of
0.25% [5]. The main source s of beam loss are related to
stored... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 2 |
7cc878c8-77ac-4683-a7e3-c59f15d5728c | dispersion function , and phase advances of transverse os-
cillations , remain the same. The PSR revolution frequency
is changed from nominal value of f 0 = 2.792424 MHz to
new value
𝑓𝑓=𝑓𝑓𝑜𝑜 𝛽𝛽700
𝛽𝛽800=0.9738 𝑓𝑓𝑜𝑜 = 2.7192 MHz , (2)
which corresponds to revolution period of 368 ns. The ... | d:\Daily_ihep\Weekly Progress Report\20260425\37_JFIC\MOPA - MOPA MC9 Poster presentations_ MC9 Poster Presentations\THP012.pdf | 2 |
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