Usage and Billing

For any new projects the Project proposal form must be filled out and signed. The copy of the form will be emailed to the facility managers, user and their PI. For any biohazardous samples, the protocol must first be approved by the Biosafety committee. The copy of the protocol then must be forwarded to the facility managers.

Any new projects in the facility should be started on the T12. The usefulness of negatively stained images and the speed at which a new sample can be screened and optimized on the T12 should not be underestimated or ignored. To facilitate rapid screening and optimization of the sample, minimum length of a session on the T12 is half an hour. After the sample is optimized, the user can then move to either the Arctica (SP or tomography) or Polara (tomography).

Session Length

Hands on training is absolutely critical to learn how to operate the microscopes. As such, training on all microscopes can only proceed once user has a sample in hand.

Due to high number of images necessary for a single particle reconstruction and a tomographic exploration, the minimum sign up time for the Polara, the Arctica, and the Krios is 1 day. Each one day session is from 9 am to 9 am of the following day. Users are required to remove their grids by 9 am to allow for a smooth transition for the next user. The maximum session length on the Polara and the Krios is 2 days. For the Arctica, 3 day sessions can be scheduled. Under extenuating circumstances (very heterogeneous sample, etc.), longer sessions can be accommodated. Please contact staff to discuss the possibilities. To allow for an equal access to the facility’s resources, a user can only sign up for a single session at a time and only one reservation per project (multiple users may not sign up to collect on the same project). Reservations can only be made up to a month ahead of the current date. Any cancellations must be made at least 24 hours in advance of the session.

Every Monday on the Arctica is designated as a “Flex” day. The primary uses for this day are 1) for emergency collection or to make up a collection day due to unexpected microscope down time and 2) as a screening day. For screening, two 4 hour sessions can be reserved: 9 am – 1 pm, 1 pm – 5 pm. Independent users could set up an overnight collection from 5 pm to 9 am the following morning. Please be prompt in removing your grids Monday morning before 9 am and/or at the end of your screening session. The sessions on Mondays will be exempt and will not contribute to your reservation count.

Prior to collection on the Krios, grids must be screened on the Arctica to maximize collection time. For singe particle work, a reconstruction must be available from a previous collection (Arctica, Janelia, etc). Only the following tomography projects are currently allowed to use the Krios: 1. Projects that need to use phase plate; 2. Projects that use Cryo-FIB milled samples; 3. CLEM projects; 4. Technology development for fast tilt series collection. All other tomography projects should use the Polara.


Every user, regardless of the hazard level of their sample, should be prepared to discuss:

  1. Preliminary risk classification/assessment for the material they are bringing
  2. Best cleaning / disposal practices
  3. Best handling practices
  4. Minimum infectious and lethal doses
  5. For infectious agents:
    • Rates of survival on various surfaces
    • Preferred areas to infect
    • Transmission source / routes of exposure
    • Types of infections caused
    • Symptoms and incubation time
    • Types of treatment available

Copy of this information and any specific procedures necessary for the safe handling of the sample must also be provided to facility managers.


To allow for a rapid access to the facility to both experienced and labs new to cryo-EM, most of the consumables needed for an experiment are provided by the facility. These and other costs associated with the facility are incorporated into the hourly and daily rates. Labs receive a single statement once a quarter based on their usage of the microscopes. For more information about recharge rates, please contact the staff.


Due to the complexities of the instruments, user error, or unforeseen circumstances unplanned outages do occur, potentially interrupting user’s session. When this occurs, the billed usage will be rounded to the nearest half-day. Further, due to complexities of trying to shuffle everyone when outages occur, any user with an interrupted session would have to sign up for a new session at the next available time. We aim to minimize any downtime within our control.

Sample and Data Storage policies

Cryo-EM facility is a shared space open to all of Caltech researchers. Each user must return shared resources to their designated location as soon as possible. We can provide a short term space in the 4°C and -80°C fridge and freezers, as well as cryo specimen dewars. Space in dewars is allocated on per-lab bases. It is up to the lab to keep their tubes clean and share space amicably between members. Shared spaces will be regularly cleaned out and it is user’s responsibility to adequately label and store samples and reagents in order to prevent any accidental discharge of the material during cleaning.


Please provide the following statement in any publications that used center resources:

“(Cryo) Electron microscopy was done in the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech. “

Please send citation to any paper that utilized center resources to facility mangers as soon as it is published.