IBIC2013 - List of Keywords (LEFT)

Paper	Title	Other Keywords	Page
MOPC42	Novel Pickup for Bunch Arrival Time Monitor	pick-up, transverse, simulation, laser	170
	A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	For an optical-modulator-based BAM, main parameter of the pickup output signal is slope steepness. We suggest a novel pickup with flat thin electrodes in a transverse gap. Increasing the electrode width makes the steepness greater in the same extent as the signal increases. For a given width, reducing the electrode thickness allows to reach ultimate steepness. Wave processes in the pickup were investigated on a large scale model, using the technique described in . The DESY 40GHz button pickup was used as a reference. It is shown that steepness of the flat electrode pickup can be achieved two times greater. It is also shown that a BAM electrode pickup has a remarkable feature: the steepness does not depend on electrode sizes, if the ratio w/G (a flat electrode pickup, the width and gap length) or d/D (a button pickup, the diameters) is kept constant. This makes pickup bandwidth that is of the order of c over 2G or 2D, a free parameter. For flat electrode pickup, the steepness can be kept as high with transition to a more practical bandwidth 20GHz. The investigation results are the base for a final pickup optimisation using electrodynamic simulation. A. Kalinin, “Pickup Electrode Electrodynamics Investigation”, WEPC26, this conference
	Poster MOPC42 [0.549 MB]

WEPC26	Pickup Electrode Electrodynamics Investigation	pick-up, transverse, impedance, vacuum	742
	A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Waves induced in a pickup by beam were investigated on a large scale model, using 10ps step in coaxial line as beam, and a differentiating capacitive probe. The probe signal was observed at 20GHz oscilloscope. In each of the front and rear transverse gaps between pickup electrode and wall (button pickup), a shorter-than-gap bunch excites a ‘plain-wave’ packet which length is of the order of gap length over c. Two packets are spaced by electrode length over c. The packets propagate along the electrode to a coaxial connector. At this low impedance common point each of the packets partially reflects back and partially passes into the opposite gap. The voltage appearing on the impedance excites two TEM-wave packets: one propagates backwards, another one propagates forward through connector. The connector output is sum of two such packets spaced the same as two incident packets. The packets propagating backwards reflect from the electrode open end, come back to the summing point and generate output in similar way. The same processes occur in a pickup with single gap electrodes (stripline pickup). This phenomenological picture can be used as a guide in pickup design and simulation.
	Poster WEPC26 [0.647 MB]

WEPC35	Progress Report of the Spectral Decoding Based EOS with Organic Pockels EO Crystals	electron, laser, radiation, background	765
	Y. Okayasu, S. Matsubara, H. Tomizawa JASRI/SPring-8, Hyogo-ken, Japan T. Matsukawa, H. Minamide RIKEN ASI, Sendai, Miyagi, Japan K. Ogawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	Funding: Grant-in-Aid for Scientific Research (Japan Society for the Promotion of Science, Grants No. 20612024 and No. 23360045) So far, the temporal structure of ultrashort electron bunches has been extensively investigated by various kinds of electro-optic sampling (EOS) techniques, such as temporal, spectral and spatial decoding method, at several FEL accelerator facilities since early 2000’s. Inorganic Pockels EO crystals, i.e., GaP and ZnTe, have been generally utilized for the EOS. On the other hand, since mid-1980’s, organic nonlinear optical materials have been extensively investigated and DAST, which has fast temporal response in the EO effect, was developed in 1986. DAST is transparent in visible near to IR wavelength range and absorbent in 0.8-1.3 THz. We introduced the DAST crystal into the EOS and successfully demonstrated the first observation of the bunch charge distribution at the EUV-FEL accelerator, SPring-8 on February 2012*. Through the previous experiment, it is found that the EO signal intensity was gradually decreased. On March and April 2013, we prepared DAST crystals with variety of thickness and succeeded to compare EO signal intensities with different bunch charges. Recent results of both optical and structural analysis will be reported in addition to experimental results. 4-N, N-dimethylamino-4’-N’-methyl stilbazolium tosylate S. Okada et al., Japan Patent Application 61-192404 (1986) *Y. Okayasu et al., Phys. Rev. ST Accel. Beams 16, 052801 (2013)

WEPF12	Characterisation of Al-Compound Refractive Lenses for X-Rays	ESRF, photon, emittance, dipole	837
	F. Ewald, J.C. Biasci ESRF, Grenoble, France
	We report on measurements of the surface quality (shape) of aluminium compound refractive lenses using a thin collimated X-ray beam from one of our bending magnet diagnostics beam ports. Two types of lenses were tested for overall radius of curvature, surface quality and thickness: commercially available lenses (RWTH Aachen), and lenses of the same type manufactured at the ESRF. The different surface qualities can be readily discerned with our relatively simple setup. While the technique should be improved for more precise results, it already shows clearly the imperfect surface structure of the ESRF lenses. The image quality of the beam, however, is not affected to a visible extent in our emittance measurement setup at vertical emittances of typically ~ 6 pm.

WEPF15	High-Power Tests at CesrTA of X-ray Optics Elements for SuperKEKB	DIAMOND, simulation, optics, factory	844
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda KEK, Ibaraki, Japan A. Lyndaker, D.P. Peterson, N.T. Rider Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	X-ray beam size monitors at SuperKEKB must withstand high, sustained incident power loads. Two prototype optics elements were fabricated and tested at CesrTA, using incident X-ray power densities comparable to those expected at the SuperKEKB LER. One element was based on a silicon substrate, the other a CVD diamond substrate, with each substrate supporting a coded aperture mask pattern in gold on its surface. The diamond substrate mask showed superior performance to the silicon substrate mask, with the the mask pattern on the silicon substrate melting at the highest incident power level tested, where the diamond-substrate mask survived. We will present here the high-power test results, along with analysis of X-ray power absorption and heat transfer in the two prototype elements, and the resulting implications for the design of the optics, beam line and heat sink for SuperKEKB.

WEPF25	Resonator for Charge Measurement at REGAE	DESY, controls, XFEL, PITZ	872
	D. Lipka, J. Lund-Nielsen, M. Seebach DESY, Hamburg, Germany
	A resonator has been developed for the diagnostics of dark current and charge measurements at the European XFEL, FLASH and PITZ. The first induced monopole mode TM01 at 1.3 GHz from charged bunches is used to detect the dark current and charge with high resolution at these accelerators. At REGAE this resonator with electronics is installed to detect the bunch charge because charges below pC are used and this device can resolve it non-destructively. The same electronics as for the dark current and charge measurement is used and the resolution is measured to be 2.3 fC for 200 fC.
	Poster WEPF25 [0.822 MB]

Paper

Title

Other Keywords

Page

MOPC42

Novel Pickup for Bunch Arrival Time Monitor

pick-up, transverse, simulation, laser

170

A. Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

For an optical-modulator-based BAM, main parameter of the pickup output signal is slope steepness. We suggest a novel pickup with flat thin electrodes in a transverse gap. Increasing the electrode width makes the steepness greater in the same extent as the signal increases. For a given width, reducing the electrode thickness allows to reach ultimate steepness. Wave processes in the pickup were investigated on a large scale model, using the technique described in *. The DESY 40GHz button pickup was used as a reference. It is shown that steepness of the flat electrode pickup can be achieved two times greater. It is also shown that a BAM electrode pickup has a remarkable feature: the steepness does not depend on electrode sizes, if the ratio w/G (a flat electrode pickup, the width and gap length) or d/D (a button pickup, the diameters) is kept constant. This makes pickup bandwidth that is of the order of c over 2G or 2D, a free parameter. For flat electrode pickup, the steepness can be kept as high with transition to a more practical bandwidth 20GHz. The investigation results are the base for a final pickup optimisation using electrodynamic simulation.
* A. Kalinin, “Pickup Electrode Electrodynamics Investigation”, WEPC26, this conference

Poster MOPC42 [0.549 MB]

WEPC26

Pickup Electrode Electrodynamics Investigation

pick-up, transverse, impedance, vacuum

742

A. Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Waves induced in a pickup by beam were investigated on a large scale model, using 10ps step in coaxial line as beam, and a differentiating capacitive probe. The probe signal was observed at 20GHz oscilloscope. In each of the front and rear transverse gaps between pickup electrode and wall (button pickup), a shorter-than-gap bunch excites a ‘plain-wave’ packet which length is of the order of gap length over c. Two packets are spaced by electrode length over c. The packets propagate along the electrode to a coaxial connector. At this low impedance common point each of the packets partially reflects back and partially passes into the opposite gap. The voltage appearing on the impedance excites two TEM-wave packets: one propagates backwards, another one propagates forward through connector. The connector output is sum of two such packets spaced the same as two incident packets. The packets propagating backwards reflect from the electrode open end, come back to the summing point and generate output in similar way. The same processes occur in a pickup with single gap electrodes (stripline pickup). This phenomenological picture can be used as a guide in pickup design and simulation.

Poster WEPC26 [0.647 MB]

WEPC35

Progress Report of the Spectral Decoding Based EOS with Organic Pockels EO Crystals

electron, laser, radiation, background

765

Y. Okayasu, S. Matsubara, H. Tomizawa
JASRI/SPring-8, Hyogo-ken, Japan
T. Matsukawa, H. Minamide
RIKEN ASI, Sendai, Miyagi, Japan
K. Ogawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Funding: Grant-in-Aid for Scientific Research (Japan Society for the Promotion of Science, Grants No. 20612024 and No. 23360045)
So far, the temporal structure of ultrashort electron bunches has been extensively investigated by various kinds of electro-optic sampling (EOS) techniques, such as temporal, spectral and spatial decoding method, at several FEL accelerator facilities since early 2000’s. Inorganic Pockels EO crystals, i.e., GaP and ZnTe, have been generally utilized for the EOS. On the other hand, since mid-1980’s, organic nonlinear optical materials have been extensively investigated and DAST*, which has fast temporal response in the EO effect, was developed in 1986**. DAST is transparent in visible near to IR wavelength range and absorbent in 0.8-1.3 THz. We introduced the DAST crystal into the EOS and successfully demonstrated the first observation of the bunch charge distribution at the EUV-FEL accelerator, SPring-8 on February 2012***. Through the previous experiment, it is found that the EO signal intensity was gradually decreased. On March and April 2013, we prepared DAST crystals with variety of thickness and succeeded to compare EO signal intensities with different bunch charges. Recent results of both optical and structural analysis will be reported in addition to experimental results.
*4-N, N-dimethylamino-4’-N’-methyl stilbazolium tosylate
**S. Okada et al., Japan Patent Application 61-192404 (1986)
***Y. Okayasu et al., Phys. Rev. ST Accel. Beams 16, 052801 (2013)

WEPF12

Characterisation of Al-Compound Refractive Lenses for X-Rays

ESRF, photon, emittance, dipole

837

F. Ewald, J.C. Biasci
ESRF, Grenoble, France

We report on measurements of the surface quality (shape) of aluminium compound refractive lenses using a thin collimated X-ray beam from one of our bending magnet diagnostics beam ports. Two types of lenses were tested for overall radius of curvature, surface quality and thickness: commercially available lenses (RWTH Aachen), and lenses of the same type manufactured at the ESRF. The different surface qualities can be readily discerned with our relatively simple setup. While the technique should be improved for more precise results, it already shows clearly the imperfect surface structure of the ESRF lenses. The image quality of the beam, however, is not affected to a visible extent in our emittance measurement setup at vertical emittances of typically ~ 6 pm.

WEPF15

High-Power Tests at CesrTA of X-ray Optics Elements for SuperKEKB

DIAMOND, simulation, optics, factory

844

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda
KEK, Ibaraki, Japan
A. Lyndaker, D.P. Peterson, N.T. Rider
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

X-ray beam size monitors at SuperKEKB must withstand high, sustained incident power loads. Two prototype optics elements were fabricated and tested at CesrTA, using incident X-ray power densities comparable to those expected at the SuperKEKB LER. One element was based on a silicon substrate, the other a CVD diamond substrate, with each substrate supporting a coded aperture mask pattern in gold on its surface. The diamond substrate mask showed superior performance to the silicon substrate mask, with the the mask pattern on the silicon substrate melting at the highest incident power level tested, where the diamond-substrate mask survived. We will present here the high-power test results, along with analysis of X-ray power absorption and heat transfer in the two prototype elements, and the resulting implications for the design of the optics, beam line and heat sink for SuperKEKB.

WEPF25

Resonator for Charge Measurement at REGAE

DESY, controls, XFEL, PITZ

872

D. Lipka, J. Lund-Nielsen, M. Seebach
DESY, Hamburg, Germany

A resonator has been developed for the diagnostics of dark current and charge measurements at the European XFEL, FLASH and PITZ. The first induced monopole mode TM01 at 1.3 GHz from charged bunches is used to detect the dark current and charge with high resolution at these accelerators. At REGAE this resonator with electronics is installed to detect the bunch charge because charges below pC are used and this device can resolve it non-destructively. The same electronics as for the dark current and charge measurement is used and the resolution is measured to be 2.3 fC for 200 fC.

Poster WEPF25 [0.822 MB]