Progress in the interaction region magnets of HL-LHC

Panagiotis Charitos — Mon, 06 Mar 2017 14:06:40 +0000

Progress in the interaction region magnets of HL-LHC
by Ezio Todesco (CERN)

During the past months, significant advancements have been done in the development of the interaction region magnets for HL-LHC.

In KEK, Japan, the short model of the separation dipole D1, that showed insufficient quench performance after the first test, has been disassembled. Significant movements of the coils (up to few mm) were observed in the heads, and a clear evidence of a lack of prestress in the straight part was found. The new assembly took place during winter, and a prestress increase in the straight part of about 35 MPa has been achieved. The magnet was tested in February, reaching nominal current after 2 quenches and ultimate after 5 quenches (see Figure 1). “The magnet performance is now in line with the project requirements – says T. Nakamoto, in charge of the D1 project – we will have a warm-up and cool-down to prove the magnet memory in the next weeks”. The short model design is being updated in some features of the iron yoke, and to account for an unexpected contribution to field quality from the coil heads in the strong regime of saturation. A second model will be built in the second part of 2017, and tested in 2018.

Figure 1: Training of MBXFS1 in KEK: quenches (markers), nominal and ultimate current (solid lines) and short sample limit (dotted line). (Credit: HL-LHC WP3 collaboration)

In the US, the first 4-m-long coil has been tested in a mirror configuration, reaching 85% of short sample limit (see Figure 2). “This is the new world record for coil length in Nb₃Sn accelerator magnets – says G. Ambrosio, in charge of the US contribution for the triplet - and paves the way to the assembly and test of the first 4-m-long quadrupole, to be done in the second part of the year”. At the same time at CERN the first 7.15-m-long dummy coils are being produced to validate the assembly procedures (see Figure 3).

Figure 2: Training of mirror 4-m-long coil in BNL: quenches (markers), 70% and 80% of short sample (solid lines) and short sample limit (dotted line). (Credit: HL-LHC WP3 collaboration)

Figure 3: Winding of the first 7.15-m-long dummy coil of the triplet quadrupole at building 180 (CERN)

Furthermore, in CIEMAT, Madrid, the prototype for the nested orbit correctors is entering the construction phase. The concept of double collaring has been validated on a mechanical model with the final design of the collars and a dummy coil made of aluminum (see Figure 4). This is an important step of the validation of the mechanical concept of this magnet, where a mechanical lock between the horizontal and vertical dipoles is required to control the large torque. In particular, the second collaring of the outer dipole on the inner one is critical. “Both collaring operations were in line with our expectations, and we managed to insert pins without any criticality – said F. Toral from CIEMAT, in charge of the Spanish contribution for the orbit correctors – we saw some asymmetries that need more investigations, but given the complexity of the design, this is a very encouraging first step towards construction”.

Figure 4: Double collaring of the nested corrector in CIEMAT

Finally, in LASA, Milano the activity on the high order corrector prototypes is at full speed. After the successful test of the sextupole, the first decapole coil in a single coil configuration has been tested successfully. The coil reached twice the ultimate current with negligible training, thus proving the assembly procedures and tooling concepts. LASA is working in parallel on two magnets: besides the first decapole coil, eigth octupole coils have been completed and will be assembled in the first prototype, and tested in April.

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issue 20

Accelerating medical treatments

Sabrina El Yacoubi — Wed, 17 Sep 2014 13:54:13 +0000

Accelerating medical treatments
by Kate Kahle (CERN)

Image 1: Extract from "Novel Techniques in Proton Therapy" presented at ICTR-PHE 2012 showing the usability of different types of accelerators for proton therapy now and in the future (click image to enlarge). Image credit: Marco Schippers, PSI.
Image 2: Conceptual design for the CIEMAT/CERN smallest-possible superconducting cyclotron for medical isotopes, with a magnet only 0.8 m in diameter. Image credit: CIEMAT.

In February, the physics and medical communities came together at the ICTR-PHE 2012 conference in Geneva. Within the scientific programme, the session "Novel Technologies in Radiation Therapy" looked at the present and emerging roles of accelerators in medical treatments.

The session opened with "Novel Techniques in Proton Therapy" by Marco Schippers, PSI, who explained the need for high quality, accuracy, flexibility, intensity and energy coupled with low prices and hence reduction in size. Currently the cyclotron scores the highest for usability for proton therapy, but, in the future, linacs, FFAG and plasma wakefield may also prove usable options.

In addition, Dewi Lewis, in his highlight talk at the EuCARD annual meeting, presents "Evolution of accelerator design for medical isotopes production", linked to his recent article in the CERN Courier "Medical-isotope cyclotron designs go full circle", This article examines the role of cyclotrons in medicine over the years and discusses the interplay that has existed between industry and the accelerator laboratories. The article showcases the latest collaboration between CERN and CIEMAT, using LHC accelerator technology and expertise to help design and build the smallest-possible cyclotron using superconducting technology with a proton energy of around 8 MeV, the objective being to produce single-patient doses of radioisotopes.

accelerating-news-arc.web.cern.ch - CIEMAT

Progress in the interaction region magnets of HL-LHC

Accelerating medical treatments