PIP-II successfully accelerates beam using RF power amplifiers from India

Nilgiri

Experienced member
Moderator
Canada Moderator
India Moderator
Joined
Aug 23, 2020
Messages
3,799
Reaction score
7,646
Points
113
Nation of residence
Canada
Nation of origin
India

Fermilab is embarking on a major upgrade to its accelerator complex. The new PIP-II particle accelerator will provide greater than a megawatt, upgradeable to multi-megawatt, proton beam power for the laboratory’s experiments. PIP-II is the first U.S. accelerator project that will receive significant contributions from international partners. Institutions in France, India, Italy, Poland, the United Kingdom and the United States are collaborating on the project.

Institutions in India are building major components for the new accelerator upgrade, including radio frequency power amplifiers. These amplifiers power PIP-II components that accelerate the particles. Each of the 119 superconducting cavities in the PIP-II linac has a dedicated power amplifier, and our Indian partner, the Department of Atomic Energy, or DAE, is providing solid-state RF power amplifiers to power 111 of them. In recent testing, the nine power amplifiers DAE has provided so far showed stellar performance for all critical parameters, and enabled beam acceleration in the PIP-II Injector Test Facility, or PIP2IT, at Fermilab.

About 26 people, mostly men and a few women, stand in a horseshoe shape under a drop-tile ceiling and fluorescent lights in an office.
Members of the team that works on the design, development and construction of RF power amplifiers for PIP-II met at the Department of Atomic Energy’s Electronics Corporation of India Limited in Hyderabad in 2018. Credit: Electronics Corporation of India Limited


Fifty-one of the cavities in PIP-II will be single-spoke-resonator-style and operate at 325 megahertz, or MHz; the other 60 cavities will be elliptical-style and resonate at 650 MHz.

There are two types of SSR-style cavities used in the PIP-II linac: SSR1, which requires up to 7 kilowatts, or kW, of power to accelerate the proton beam, and SSR2, which requires 20 kW of power to accelerate the beam further.

There are also two types of elliptical cavities used in the PIP-II linac: the low-energy cavities, which require up to 40 kW of power to accelerate the beam, and the high-energy cavities, which require up to 70 kW of power.

The amplifiers that drive the SSR cavities will be tuned to 325 MHz and are being designed by the Bhabha Atomic Research Centre in Mumbai. They are being constructed in a collaboration between BARC and the Electronics Corporation of India Limited in Hyderabad, both DAE institutes.


Eight gray boxes that look like high-tech household refrigerators sit diagonally from foreground to background on a concrete floor. Wires hang behind and a person facing away from the camera sits behind on the left side.
The PIP-II team successfully tested the first eight RF amplifiers, which the Department of Atomic Energy in India provided for the new PIP-II particle accelerator at Fermilab. Credit: Jim Steimel, Fermilab

The collaboration has already designed, constructed and delivered nine of the 325 MHz, 7 kW RF power amplifiers for SSR1 cavities. These amplifiers were recently used in a test of the low-energy portion of the PIP-II linac, housed in the PIP2IT facility. The team completed the testing of these amplifiers and placed them into service on Dec 17, 2020, and they were operated for over 300 hours until PIP2IT was shut down on April 23, 2021.The amplifiers provided the power to successfully accelerate 2 milliamps of particles through eight SSR1 cavities to a beam energy of up to 17 mega electronvolts, or MeV. The PIP2IT configuration required a peak power level of 4kW from the amplifiers to accelerate the full beam intensity.

All the efforts put into designing, developing, engineering, qualifying and testing of these amplifiers paid off when the amplifiers DAE provided showed stellar performance for all critical parameters. These parameters include wall power to RF efficiency, overall gain, gain magnitude and phase variation, group delay, harmonic contents, spurious outputs and more.

The solid-state RF power amplifiers that DAE provided offer many benefits, such as high reliability, modularity, graceful power degradation, use of lower bias voltages with higher currents and low maintenance.

Industrial grade components, innovative design techniques, direct-current-bias supplies with lower ripple, proper thermal management and appropriate design to reduce thermal drift have resulted in better amplifier-performance parameters, which improve accelerator operation.

The other set of RF power amplifiers provided by DAE, for the elliptical cavities, are tuned to 650 MHz and are being designed by the Raja Ramanna Centre for Advanced Technology in Indore. The laboratory has already delivered a first unit to Fermilab for testing with high-energy cavities at the PIP2IT facility.

While the assembly and testing of components for the PIP-II test accelerator proceeds, the construction of the buildings for housing the new accelerator at Fermilab is also ongoing. Once the construction is complete, the RF power amplifiers will be moved from their PIP2IT test site to the new buildings for the assembly of the new PIP-II particle accelerator.

Manjiri Pande is a scientific officer at Bhabha Atomic Research Centre, or BARC, and is the sub-project coordinator for 325 MHz RF power in IIFC. Jim Steimel is the level-3 manager for high-power RF for PIP-II and is the sub-project manager for 325 MHz and 650 MHz RF Power in Indian Institutes & Fermilab Collaboration, or IIFC.
 

Nilgiri

Experienced member
Moderator
Canada Moderator
India Moderator
Joined
Aug 23, 2020
Messages
3,799
Reaction score
7,646
Points
113
Nation of residence
Canada
Nation of origin
India
Earlier convo on this matter for context (and quote arrow can be used for more) for interested readers :

Recently found two Super Conducting Neobium Cell Cavities being made using Electron Beam Welding for a RRCAT Particle Accelerator. Here is a 650MHz cavity :
View attachment 3297

And the 9-cell cavity with combined capacity of 1.3GHz :
View attachment 3298
This is the perplexing piece of hardware. Why do we have it ? The current particle accelerators in the country are decades old. Why are we making new cavities that were never a part of the original design ?
View attachment 3300

The most powerful accelerator we have today is the "Indus 2" with a Synchrotron power level of 2.5 GeV. There is a new still proposed accelerator
called the International Linear Collider (ILC), which is a collaboration between USA, Europe & Japan, also uses a 1.3 GHz cavity.
View attachment 3280
The ILC is far more powerful than any present RRCAT accelerator. The ILC will begin operations at 500 GeV, then it will be ramped up to 1 TeV.

So how come we are making the same hardware as them ? The only logical explanation is that we might have a new accelerator under construction. The last one was built 15 years ago, its about time.

When Dr. Kalam was the president he visited Fermilabs in the USA. Where the then director of Fermilabs insisted on India's (in particular RRCAT's) participation in the ILC. That never happened though. RRCAT also participated heavily in CERN's Large Hadron Collider.

It seems to be a further development from existing 500 Mhz cavity:


Next, a major effort has been launched on the development of superconducting radio frequency (SCRF) cavities required for the development of high energy proton accelerators for spallation neutron source and accelerator driven system.

A large facility is being set up for SCRF cavity fabrication, processing, assembly and testing. Recently developed prototype 1.3 GHz single-cell niobium SCRF cavities have shown excellent performance providing acceleration gradient exceeding 35 MV/m with a quality factor of 2x1010 at 2 K.

Other highlights on the technological accomplishments include indigenous development of helium liquefier, high power solid state RF amplifiers as an import substitute for klystron source, and development of nonevaporable getter coatings to achieve vacuum better than 10-11 mbar. In this talk, an overview of the accelerator activities at RRCAT will be presented

More Ongoing collaboration:

 
Top Bottom