Effects of bunch state on measurement of beam emittance and energy

Chaofan An; Xiucui Xie; Yuehu Pu

doi:10.11884/HPLPB202133.210302

Journals >High Power Laser and Particle Beams >Volume 33 >Issue 11 >Page 114001 > Article

High Power Laser and Particle Beams
Vol. 33, Issue 11, 114001 (2021)

Effects of bunch state on measurement of beam emittance and energy

Chaofan An^1、2, Xiucui Xie^1、*, and Yuehu Pu^3、4

Author Affiliations

¹Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China

²University of Chinese Academy of Sciences, Beijing 100049, China

³Shanghai APACTRON Particle Equipment Co, Ltd, Shanghai 201800, China

⁴Shanghai Institute of Advanced Studies, Chinese Academy of Sciences , Shanghai 201210, China

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DOI: 10.11884/HPLPB202133.210302 Cite this Article

Chaofan An, Xiucui Xie, Yuehu Pu. Effects of bunch state on measurement of beam emittance and energy[J]. High Power Laser and Particle Beams, 2021, 33(11): 114001 Copy Citation Text

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Fig. 1. Schematic diagram of the beam energy measurement system

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Fig. 2. The beam measurement system design structure diagram

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Fig. 3. The results of simulated measurement of the APF output beam

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Fig. 3. [in Chinese]

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Fig. 4. Relationship between the magnetic field gradient of the third magnet and the position of the screen 第3块磁铁磁场梯度变化与荧光靶处的关系

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Fig. 5. The relation between j₀−j and kinetic energy

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Fig. 6. The relation between j₀−j and j₀−j和的关系

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Fig. 7. Tracewin simulated beam current distribution using the Faraday cup

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particle bunch	${\alpha }_{x}$	$\;{\beta }_{x}$/(mm/(π·mrad))	${\alpha }_{y}$	$\;{\beta }_{y}$/(mm/(π·mrad))	${\alpha }_{{\textit{z}} }$	$\;{\beta }_{{\textit{z}} }$/(mm/(π·mrad))	x−x′/(mm/(π·mrad))	y−y′/(mm/(π·mrad))	${E}_{K}$/MeV
ideal bunch	0.115	0.785	0.121	0.760	−1.861	2.781	0.314	0.315	6.98
non-ideal bunch	0.020	0.640	0.027	0.617	−3.308	1.697	0.376	0.377	6.79

Table 1. Initial parameters of ideal and non-ideal bunch

name	emittance of ideal bunch (normalized RMS)/( $\mathrm{ {\text{π} } }\cdot\mathrm{m}\mathrm{m}\cdot\mathrm{m}\mathrm{r}\mathrm{a}\mathrm{d}$)		emittance of non-ideal bunch (normalized RMS)/( $\mathrm{ {\text{π} } }\cdot \mathrm{m}\mathrm{m}\cdot \mathrm{m}\mathrm{r}\mathrm{a}\mathrm{d}$)
direction	x	y	x	y
emittance at entrance obtained by the least square method	0.302	0.302	0.821	0.433
calculated input emittance of the software	0.288	0.302	0.376	0.377
relative error/%	4.64	0	118.35	14.85

Table 2. The results of the emittance at the entrance obtained by the two methods and their relative errors

j₀−j/(°)	initial beam emittance (normalized RMS)/( $\mathrm{ {\text{π} } }\cdot\mathrm{m}\mathrm{m}\cdot\mathrm{m}\mathrm{r}\mathrm{a}\mathrm{d}$)		fitting the emittance of beam (normalized RMS)/( $\mathrm{ {\text{π} } }\cdot\mathrm{m}\mathrm{m}\cdot\mathrm{m}\mathrm{r}\mathrm{a}\mathrm{d}$)		relative error/%
direction	x	y	x	y	x	y
1080	0.376	0.377	0.337	0.357	10.37	5.3
1260	0.376	0.377	0.363	0.364	3.46	3.45
1440	0.376	0.377	0.402	0.370	6.91	1.86
1620	0.376	0.377	0.457	0.376	21.54	0.27
1800	0.376	0.377	0.515	0.383	36.97	1.59
2160	0.376	0.377	0.774	0.410	105.85	3.3
2340	0.376	0.377	0.819	0.432	117.82	14.59

Table 3. Simulated emittance measurement results after changing phase difference

particle bunch	the highest point where the current through slit2 deviates from point J/mm	energy spread/ MeV	degree of energy spread/%	relative error with standard energy /%
ideal bunch	−0.375	0.07444	1.2	0.09
non-ideal bunch	−7.5	0.0796	1.15	1.77

Table 4. Simulation results of beam energy measured by analyzing magnet

Chaofan An, Xiucui Xie, Yuehu Pu. Effects of bunch state on measurement of beam emittance and energy[J]. High Power Laser and Particle Beams, 2021, 33(11): 114001

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