R.Y. Qiu, W.L. Huang, F. Li, M.A. Rehman, Z.X. Tan, Zh.H. Xu, R.J. Yang, T. Yang
IHEP CSNS, Guangdong Province, People’s Republic of China
M.Y. Liu, L. Zeng
IHEP, Beijing, People’s Republic of China
Q.R. Liu
UCAS, Beijing, People’s Republic of China
Funding:National Natural Science Foundation, U2032165 The Associated Proton beam Experiment Platform (APEP) beamline is the first proton irradiation facility to use naturally-stripped protons which come from H− beams interacting with the residual gas in the linac beampipe at CSNS. The stripped beam current, which is in the order of 0.1% of the original H− beam and approximately 10 mi-croamperes, should be measured precisely to provide the proton number for irradiation experiments. Therefore, a low-intensity beam current measurement system was developed with considerations to eliminate the external interferences. An anti-interference design is adopted in this system with an elaboration of probes, cables and electronic low-noise technology to minimize the impact of environmental noise and interferences. This improves the signal-to-noise ratio and enables a more precise measurement of the microampere-level pulsed beam cur-rent. The system was installed and tested during the summer maintenance in 2021 and 2022. It shows a good agreement with the measurement of the Faraday cup.
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L. Crescimbeni, D.M. Haider, A. Reiter, M. Schwickert, T. Sieber, T. Stöhlker
GSI, Darmstadt, Germany
D.M. Haider
TEMF, TU Darmstadt, Darmstadt, Germany
M. Schmelz, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
F. Schmid, V. Tympel
FSU Jena, Jena, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker, V. Tympel
HIJ, Jena, Germany
V. Zakosarenko
Supracon AG, Jena, Germany
Funding:Work supported by the BMBF under contract No. 05P21SJRB1. The Cryogenic Current Comparator (CCC) is a superconducting device based on an ultrasensitive SQUID (fT range). Measuring the beam¿s azimuthal magnetic field, it provides a calibrated non-destructive measurement of beam current with a resolution of 10 nA or better, independent from ion species and without tedious calibrations procedure. The non-interceptive absolute intensity measurement of weak ion beams (< 1 µA) is essential in heavy ion storage rings and in transfer lines at FAIR. With standard diagnostics, this measurement is challenging for bunched beams and virtually impossible for coasting beams. To improve the performance of the detector several upgrades are under study and development: One is the investigation of a new type of CCC using an alternative magnetic shield geometry. The so-called ‘axial¿ geometry will allow for much higher magnetic shielding factor, an increased pick-up area, and a lower low frequencies noise component. Further improvements and optimizations of the detector will be presented. The CCC will be tested on the beamline at the end of 2023 allowing to define the best possible version for FAIR.
T. Sieber, L. Crescimbeni, D.M. Haider, M. Schwickert, T. Stöhlker
GSI, Darmstadt, Germany
D.M. Haider, N. Marsic
TEMF, TU Darmstadt, Darmstadt, Germany
M. Schmelz, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
F. Schmid
FSU Jena, Jena, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker, V. Tympel
HIJ, Jena, Germany
J. Tan
CERN, Meyrin, Switzerland
V. Zakosarenko
Supracon AG, Jena, Germany
The Cryogenic Current Comparator (CCC) is a SQUID based superconducting device for intensity measurement, firstly proposed as a beam diagnostics instrument in the 90s at GSI. After prove of principle the CCC was introduced into other facilities, attesting great potential for high resolution measurements but at the same time considerable mechanical and cryogenics challenges and costs. In the course of plannings for FAIR the CCC has been revitalized. Systematic investigations started, involving commercially available SQUID systems, which led to improvements of detector and cryostat. The developments resulted in nA spill measurements at GSI (2014) followed by the installation of a CCC in CERN Antiproton Decelerator (AD), which has in the meantime become a key instrument. Since then optimization of the device is ongoing, with respect to various operating conditions, system robustness, current resolution and last but not least system costs. Alternative CCC versions with improved magnetic shielding have been developed as well as ¿Dual Core‘ versions for background noise reduction. We give an overview of CCC optimization and development steps, with focus on applications at GSI and FAIR.
N.J. Evans, A.R. Oguz, W.D. Willis
ORNL RAD, Oak Ridge, Tennessee, USA
Funding:This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). We describe the Image Acquisition system for the Injection Dump. This system visualizes the different beamlets, on the vacuum window after the H− beam is stripped of its electrons by two stripper foils. One beamlet is from H− with its electrons stripped by the first foil and the second beamlet has it final electron stripped by the second foil. We used the PXI platform to implement the data-acquisition including timing decoder. We describe the hardware and software for the system. We use a standard non-radhard GigE camera to acquire the image from the luminescent coating on the dump vacuum window. To lower the radiation damage to the camera, we shield it with stainless steel blocks. We present radiation measurements before and after shielding. We also show the radiation damage over time to estimate the camera’s lifetime.
