The 14th Kagra International Workshop

15 May 2026, 08:00 → 16 May 2026, 23:05 Europe/Rome

Sina Brufani Hotel (Perugia - Italy)

The 14th KAGRA International Workshop (KIW 14) will take place on 15–16 May 2026 in the Raffaello Room at the Sina Brufani Hotel, in Perugia 

The KAGRA International Workshop focuses not only on the KAGRA project but also on the other gravitational wave detector experiments, gravitational wave sciences, and multi-messenger astronomy.

This workshop is open to all scientists who are interested in gravitational wave-related research and multi-messenger astronomy.

Back-to-back event

May 14th is reserved to the open ceremony of the CAOS International Laboratory. CAOS inauguration Indico website and registration.

 

Please beware of fake e-mails attempting to offer you to book accommodation. This meeting does not foresee any proceedings. Beware of phishing emails. The only reliable communications are those that come directly from the organisers.

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Friday 15 May

08:00 → 09:00 Registration

09:00 → 09:30 Opening and Introduction

09:00 Opening

Speaker: Helios Vocca (Università di Perugia)

09:10 Welcome talk

Speaker: Patrizia Cenci (INFN Perugia)

09:20 Welcome talk

Speaker: Alessandro Paciaroni (Università di Perugia)

09:30 → 10:00 The CAOS International Laboratory

10:00 → 11:00 Kagra present status

Convener: Masaki Ando

11:00 → 11:30 Coffee break

11:30 → 13:00 Other present and 3G detectors status

Convener: Takafumi Ushiba

11:30 The Status of Virgo

Speaker: Marie-Anne Bizouard

11:50 The Status of LIGO

12:10 The Status of Einstein Telescope

Speaker: Michele Punturo

12:30 The Status of Cosmic Explorer

Speaker: David H Shoemaker

13:00 → 14:30 Lunch

14:30 → 19:00 Instrumentation

Convener: Shinji MIYOKI

16:30 Coffee break

17:00 Evaluation of the vibration noise for KAGRA detector

KAGRA is a kilometer-scale gravitational-wave interferometer located in Japan. It has two unique features: a cryogenic environment and an underground site. KAGRA joined the O4c observing run in July 2026 with a binary neutron star merger range of 7.5 Mpc. In this talk, we present an evaluation of various environmental noise sources affecting the KAGRA detector, with a particular focus on vibrational noise. We also report measurements of the resonant frequencies of optics installed in the pre-stabilized laser (PSL) room, obtained through shaker injection and tapping tests.

Speaker: Takaaki Yokozawa (ICRR, University of Tokyo, Japan)

17:20 KAGRA Underground Environment: O4c and a Quiet Period

We present a summary of environmental data measured in the KAGRA underground site during O4c, focusing on the period from June to November 2025. The data include seismic motion, acoustic noise, magnetic field, temperature, humidity, atmospheric pressure, and outside weather information. These measurements provide an overview of the underground environmental conditions relevant to KAGRA detector characterization and site studies.

We also analyze environmental data taken during an electrical facility inspection with a site-wide power outage in March 2026. This period offers a rare opportunity to study the underground environment under unusually quiet conditions. By comparing the power-outage period with normal operation, we evaluate changes in the environmental spectra and fluctuations in each channel and discuss contributions from facility operation and human activity.

These results provide a quantitative picture of the KAGRA underground environment during O4c and a reference for exceptionally quiet conditions, which will be useful for future environmental monitoring and detector characterization studies, such as the ET.

Speaker: Tatsuki Washimi (NAOJ)

17:40 Birefringence measurement and mitigation techniques

KAGRA is the only gravitational wave detector operating with crystalline test-masses at cryogenic temperature. While this allow to reduce the thermal noise of the detector, this comes at the expense of operating with complex test-masses. One issue, is the birefringence of these test-masses that can spoil the detector sensitivity.

In this talk, we will report about the techniques developed to measure the birefringence of large sapphire substrates forming KAGRA test-masses as well as the birefringence mitigation and compensation techniques being currently developed towards a possible installation in KAGRA

Speaker: Marc Eisenmann (NAOJ)

18:00 Quantum noise reduction schemes for KAGRA post-O5

Quantum noise has been the limiting noise at high frequency and a relevant noise at low frequency for the sensitivity of current gravitational wave detectors. It is also expected to be a limiting noise source for future interferometric gravitational wave detectors across the whole frequency band. Squeezed vacuum has become a standard tool for reducing quantum noise and led to up to 65\% increase of detection rate for current gravitational wave detectors. To reduce quantum noise over a broad frequency band, current solution is to combine squeezed vacuum with a hundred-meter long, detuned, and over-coupled optical cavity, usually called filter cavity. However, there are many other quantum noise reduction techniques. For certain cases, the noise limitation from other noise sources is relatively high at low frequency, which makes the consideration of various quantum noise reduction technique necessary. In the context of KAGRA post O5, we have compared quantum noise reduction schemes, including single-mode squeezing technique (frequency independent squeezing, frequency dependent squeezing with filter cavity or amplitude filter cavity or frequency dependent beam splitter) and two-mode squeezing technique (EPR scheme). We find that the behavior of suspension thermal noise and mirror thermal noise plays crucial role for deciding which quantum noise reduction scheme is more suitable. We also analyzed the difference of filter cavity and EPR scheme when the losses and length of the filter cavity is varied.

Speaker: Yuhang Zhao (Henan Academy of Sciences)

19:00 → 19:50 Poster session

Convener: Helios Vocca (Università di Perugia)

20:30 → 23:30 Social Dinner

Saturday 16 May

09:30 → 13:00 Data Analysis and Computing

11:00 Coffee break

13:00 → 14:30 Lunch

14:30 → 16:00 Science

Convener: Hideyuki Tagoshi

16:00 → 16:30 Coffee break

16:30 → 18:20 Multi-messenger

Convener: Michele Punturo

18:20 → 19:20 KAGRA R&D

Convener: Takayuki Tomaru

19:20 → 19:25 Announcement of the next KIW

19:25 → 19:35 Group picture

19:35 → 21:35 Social Event