Experimental Irradiation Room

The beam distribution in the experimental room will be performed with the same active scanning system in use in the treatment rooms. In order to make the best use of the available space, the part of beamline inside the experimental room can be assembled in various configurations. In the first case the irradiation point is as downstream as possible in order to get the maximum irradiation field. In the opposite case, the irradiation point is just at the beam entrance into the room, leaving the maximum space downstream for, e.g., Time Of Flight measurements; this configuration requires to remove the whole beam line starting with the scanning magnets. An intermediate irradiation position has been chosen as default leaving almost 2 m free space downstream the irradiation point and still allowing an irradiation field of 135 × 135 mm². A fourth configuration allowing beam monitoring in the most upstream position completes the possibilities.

Beam specifications

The CNAO synchrotron was designed for particle therapy which requires energies up to 400 MeV/u for carbon ions (corresponding to a Bragg peak depth of up to 27 cm in water) and up to 230 MeV for protons (corresponding to a Bragg peak depth of up to 32 cm in water). The maximum proton energy available is 250 MeV, included in the initial CNAO specification for a hypothetic passive system. The minimum extraction energies are 60 MeV and 120 MeV/u for protons and carbon respectively. All the intermediate energies are possible and are distributed in steps of 1 mm range rather than in fixed energy steps. The intensities needed for therapy are relatively low, < 10¹⁰ protons/spill (p/spill) and < 4×10⁸ Carbon ions/spill (C/spill), with one second long spills every three seconds approximately. In the treatment rooms, the beam is distributed into the patient, but into any target as well, with an active beam delivery system. To explain what this means, consider the tumour inside the patient and subdivide it in iso-range slices. The beam energy is at first set such that the Bragg peak is in the first slice. The beam is displaced with two scanning magnets to paint the slice in order to deliver the planned dose to every spot. The transverse beam size in the treatment rooms is approximately 10 mm Full Width at Half Maximum (FWHM), the beam size depending on particle and energy, and the beam can be scanned over a 200 x 200 mm² area (field size). The typical slice thickness in water is 2 mm, which can be increased to 4 mm with a ripple filter. During normal operation, the beam intensity and position are measured in real time with a set of ionization chambers placed just after the vacuum window next to the “isocenter”, the irradiation position. The beam delivery is “dose driven”, which means that the beam is displaced to the next spot when the desired dose in the current spot is reached. When the “slice” is completed, or when the next spot is not adjacent to the current one, the beam is turned off by a fast device called “HEBT Chopper” that directs it onto a dump until the system is ready to irradiate the next spot. Lower intensities are possible, down to a few thousand particles per second, but in case of very low intensities the dose delivery system is blind and the beam has to be setup with a feedback from the user itself. A low intensity monitor is presently in a design phase.

The beam distribution system used in the experimental line will be the same used in the treatment rooms.
The distance between the center of the last scanning magnet and the isocenter in the treatment rooms is 5460 mm; in order to get the same field size, as in the treatment rooms, the most downstream irradiation position ends up very near to the wall (370 mm).
If the irradiation position is withdrawn so as to leave a space of 2 m from the end wall, the scanned region for the maximum energy carbon ions reduces from 200 to 135 mm. Thus depending on the size of the samples to be irradiated, one position or the other might be more convenient. The position of the irradiation point will be chosen according to the needs in terms of samples area and experimental equipment requirements around the irradiation point, as shown in the following image

User access policy

Allocation
Except for the scheduled maintenance shut-downs, beamtime is expected to be available for external users in night (22:00-4:30) shifts during the week and in any of the three possible shifts morning (6:00-14:00)/afternoon (14:00-22:00)/night (22:00-6:00) during weekends.
Preferred dates and unacceptable periods (declared while submitting the proposal) are taken into account as best as possible.

Safety terms for the proposal submission
The main proposer is responsible for identifying and detailing any hazard (for people, environment and objects) related to the samples and/or equipment that will be brought to the facility for the experiment or laboratory processes to be performed at CNAO. All samples, equipment, laboratory processes and related safety issues must be thoroughly described and declared using the Safety Approval Form (SAF).
• Each proposal must be accompanied by the SAF. In the SAF you describe any hazards associated with your proposed experiment (chemical, electrical, environmental). You also provide the names of all the experimenters involved in the project.
• Only a preliminary SAF is required at proposal submission; however, the SAF should be updated when beam time is allocated. In case of any variation/upgrade of the experimental apparatus, the SAF shall be updated and the variation shall be approved by CNAO.

Evaluation
A review committee including members of CNAO and INFN evaluates and sets the priority for the received proposals.
Proposals will be reviewed and ranked by the committee on the basis of their technical feasibility, scientific and/or technological quality and also on the basis of the interest for CNAO.
After the Review Committee meeting, the principal investigator will receive notification by email, informing him/her of the number of allocated shifts and identifying a liaison scientist from CNAO who will be the primary contact for the User, will follow the experiment and facilitate its execution. The liaison scientists will be considered part of the research group that carries out the experiment.

It is normally expected that scientific outputs resulting from experiments at CNAO will be co-authored by CNAO staff.

It is also expected that users will involve CNAO in the application to get funding for the start and/or continuation of the research lines concerning the experiments. Dedicated funds for compensating beamtime are usually inserted in the budget of such applications.

Should beamtime not be allocated, a brief report will be sent by the Review Committee justifying the decision.

Costs
Beamtime can be obtained at CNAO both within the framework of a scientific collaboration and within a purely commercial/industrial agreement.
The XPR room fee due to CNAO is detailed in the CNAO price list and defined from time to time on the basis of the XPR room use request.
The fee due to CNAO will be paid by bank transfer within 30 days from invoice issue. For estimated fees above 40 kEuro, a down payment of 20% is required in advance, after the experiment approval, as confirmation of XPR room reservation.

Cell biology laboratory
If it is your intention to use the CNAO Cell biology laboratory to prepare on site samples and/or to carry out complementary tests when applying for beamtime, you will be invited to get in touch with the laboratory manager and to fill the on-line “cell lab user form” at least 1 month before the arrival.
In Italy, biological samples are classified in 4 classes of risks, from 1 (no danger), to 4 (very dangerous sample). At CNAO only class 1 samples (“biological agents non likely transmitting diseases to human beings”) can be used without any restriction.
Consumables have to be provided by the user. Applications of hazardous chemicals have to be announced and material safety data sheet (MSDS) has to be attached if needed.
Radiobiological experiments involving the use of radioactive materials are not allowed at CNAO.
For all material transported to and from CNAO European transportation regulations have to be respected.
Please refer to Angelica.Facoetti@cnao.it for any queries about your samples.

In vivo experiments
In CNAO it is possible to carry out in vivo irradiations with small animals (mice and rats) taking advantage of the nearby animal house facility of the University of Pavia, after approval by the local ethical committee. The timeplan of the project must consider the time needed to complete the paperwork for the approval. We strongly advice researchers interested in animal irradiation to contact CNAO personnel for costs and feasibility.

Irradiated samples handling
Any objects that gets irradiated at CNAO must be checked by the CNAO radiation protection service and its activity must be “zero” before it can leave CNAO alternatively an authorized transport must be paid and arranged by the PI.
So be aware that irradiated samples and/or equipment may remain at CNAO until fully decayed. In case your experiments foresees and immediate measurement and/or processing of the samples it might be necessary to bring with you the needed equipment and reagents to perform it in CNAO.

HOW TO APPLY FOR BEAMTIME

CNAO scientists contacts for information:
Angelica.Facoetti@cnao.it for radiobiology
Mario.Ciocca@cnao.it for medical physics
Marco.Pullia@cnao.it for other/general applications

SUBMIT YOUR APPLICATION: beamtime.application@cnao.it

PROPOSAL TEMPLATE

SAFETY APPROVAL FORM

BEFORE YOUR EXPERIMENT

ARRIVING AT CNAO

AFTER YOUR EXPERIMENT