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Seeking a Postdoctoral Researcher or Contract Researcher (W21184)


Research Instruments Group
RIKEN Nishina Center for Accelerator-Based Science
(Director: Tomohiro Uesaka)

Research Field

The research instruments group is the driving force at RI Beam Factory (RIBF) for continuous enhancement of activities and competitiveness of experimental research. Consisting of four teams, we are in charge of the construction, operation and improvement of the core research instruments at RIBF, such as BigRIPS in-flight separator, ZeroDegree spectrometer and SAMURAI spectrometer, and the related infrastructure and equipment.

For more information, please refer to the following webpage:
Research Instruments Group | RIKEN Nishina Center for Accelerator-Based Science

Job title and Job description

Job title, available positions

Postdoctoral Researcher or Contract Researcher, one position

Postdoctoral Researcher is defined as those who obtained a doctoral degree no more than 5 years ago.
Contract Researcher is defined as those who obtained a doctoral degree more than 5 years ago.

Job description

We are seeking a postdoctral researcher/contract researcher who conducts the research and development (R&D) of high radiation equipment of the RI beam separator BigRIPS such as the beam dump and the production target. He/She is also expected to provide the technical support for users of the RIBF facility through the delivery of radioactive-isotope (RI) beams utilizing the RI separator BigRIPS. The successful candidate will work as a member of the BigRIPS Team in the Research Instruments Group, RIKEN Nishina Center for Accelerator-Based Science.


The candidate should possess a doctoral degree in science or engineering, or is a prospective PhD candidate who is scheduled to obtain a doctoral degree in science or engineering before the first day of work. The successful candidate is expected to conduct works actively and steadily under the smooth cooperation with persons involved from inside/outside of RIKEN. Experiences in RI beam production and nuclear-physics studies using an accelerator will be regarded positively.

Work location

Branch and address

RIKEN Wako (2-1 Hirosawa, Wako, Saitama 351-0198)

Salary and benefits

  • 1.A one-year fixed-term employment contract, renewable based on evaluation, to a maximum of 5 years from the initial date of hire.
  • 2.RIKEN may adjust the above maximum period of renewability based on a) the employee’s abilities, work load at the time of contract completion, performance and work attitude and b) the continuation of the employee’s center, laboratory or project and RIKEN’s management situation and budget at the time. In principle, employment contracts will not be renewed for individuals older than 65 years.
  • 3.The employee’s period of fixed-term employment cannot exceed 10 years from the initial date of hire (or 10 years from April 1, 2013, for fixed-term employees already at RIKEN prior to this date). 
  • 4.Depending on the review of the employee’s research results on its third year, the employment contract may not be renewed beyond the third year.

In principle, the first two months of employment is considered a trial period.
Salary will be commensurate with qualifications and experience. Discretionary work, commuting and housing allowances will be provided. Social insurance will be applied.
Mandatory membership in the RIKEN Mutual Benefit Society (RIKEN Kyosaikai).

This position falls under the specialized duties discretionary work system; one working day will be calculated as 7 hours and 30 minutes.

Days off include public holidays, New Year's holidays (Dec. 29 - Jan 3), and RIKEN Foundation Day.
Paid leave includes annual paid leave (up to 20 days depending on the month of employment), special paid leave (childcare, family nursing care, etc.), and work life balance holidays (up to 7 days depending on the month of employment).
There are also additional leave systems such as maternity leave, childcare leave, and family nursing care leave.
RIKEN has introduced telework as a temporary and special measure to prevent the spread of COVID-19. You may be asked to work from home according to the instructions of the institute. You can also choose to work from home with the permission of your supervisor.
No smoking on site (designated smoking areas available).
These and other provisions are in accordance with RIKEN regulations.

RIKEN is actively undertaking initiatives to promote gender equality and diversity, and moving forward with the establishment of a diverse and vibrant research environment. If multiple candidates are found to have the same aptitude following a fair assessment, active efforts will be made to recruit female candidates.

Also, eligible for an exemption from repayment for category 1 scholarship loans provided by the Japan Student Services Organization before fiscal year 2003, and eligible applying for the MEXT Grants-in-Aid for Scientific Research (Kakenhi).

Application and required documents

Required documents

  • 1.Complete CV or CV (with photo and email address)
    • *Write the RIKEN job ad number “W21184”, indicated in the parentheses next to the job title, in the RIKEN job ad number section in the upper right corner of your CV.
  • 2.List of research achievement and publications
  • 3.A letter of recommendation from the current supervisor (If unavailable, a letter from a substitute reference will be acceptable.)
    • *Please specify the referee’s contact information (Name, affiliation, job title, phone number, and email address)
  • 4.Summary of major achievements to date and research proposal in future (two pages A4 sized paper, respectively)
  • 5.Consent form for handling personal information based on GDPR
    If you are a resident of the European Economic Area (EEA), you are required to submit the document, "Consent form for handling personal information based on GDPR" with your signature.

    *You will find detailed information about General Data Protection Regulation (GDPR) on the following website:
    Data protection | European Commission

How to apply

The above documents except the recommendation letters combined into a single PDF file should be uploaded to the following website:

Application for BigRIPS team

The file name of the PDF should contain your contact email address.
After you uploaded the PDF file, please let us (uesaka [at] riken.jp) know the file name of the uploaded file.

Recommendation letters must be directly submitted from the referees to the following website with the file name "Nishina Center research scientist [applicant’s name] (Recommendation letter)". Please specify the applicant's name, referee's name and contact information in the recommendation letter.

Application for BigRIPS team

After the referees uploaded the recommendation letter, please let us (uesaka [at] riken.jp) know the file name of the uploaded file.
If a confirmation email is not received within 7 days after submission, please contact: uesaka [at] riken.jp.

Note: All the submitted documents will not be returned.


Application must arrive by December 20, 2021 (Japan Standard Time)

Handling Personal Data

Submitted documents are strictly protected under the RIKEN Privacy Policy and will be used only for the purpose of applicant screening. Personal information will not be disclosed, transferred or loaned to a third party under any circumstances without just cause.

Selection process

Application screening and interview for selected applicants

Start of Employment

April 1, 2022 (Negotiable)

Contact Information

RIKEN Nishina Center for Accelerator-Based Science
Research Instruments Group
Director Tomohiro Uesaka
Email: uesaka [at] riken.jp
For inquiries, please send an email.