2026-10-14 @ CHESS 7b2

Under Construction

This page was auto-transcribed from handwritten notebooks and log files. We are currently reviewing for correctness and adding missing information (see TODO comments in markdown source). Use with caution.

Second CHESS beam time of the 2026-3 run cycle.

Goals

Temperature-dependent data on DHFR crystals (vector scans, 180˚ per temperature step, 280–320 K)

Participants

Steve M and Neti B from Ando lab; support from Mike P, John I, and Tricia C at CHESS.

Data

Root directory at CHESS: /nfs/chess/raw/2026-3/id7b2/meisburger/20261014

Root directory on OSN: s3://diffuse-chess-public/20261014

Beamline setup

Failed to control temperature

During beamtime, we struggled with the cryostream controller, and ultimately ended the beamtime early when it became unusable. When troubleshooting during setup, the cold stream head was swapped out. Unfortunately, we neglected to align it to the goniometer before starting data collection and didn't notice this until after data collection ended. Based on the misaligned position, the capillary was (mostly? partly?) bathed in sheath flow, which is at room temperature. Thus, the temperature values recorded below are the setpoint of the controller, but not the crystal temperature (which is likely close to room temp. for all datasets). The ambient T datasets are usable, but all the others are suspect. We plan to repeat these experiments in two weeks.

parameter	value	notes
X-ray energy	14 keV @ 0.01% bandwidth	Si 111 channel cut mono inserted
Beam size	100 µm x 100 µm	Slit-defined, no CRL. Not changed during the beamtime.
Flux	6.5 x 10¹⁰ ph/s	I2 ~72,900 / s, ICol ~270,700 / s; see SPEC `ct` output below
Background reduction	On-axis mirror with Mo tube
Centering camera	on-axis camera	New long working distance camera (as on 2026-09-30). Scalebar in screenshots: green bar, lower left.
Beamstop	Semi-transparent Mo beamstop
Data collection software	"MX Collect" (python) & SPEC	Modified by Mike P to use the new camera
Temperature control	Oxford cryostream, end-on

Steve M and Neti B arrived at ~9–10 AM. The DHFR crystals had been looped the day before by Neti; Steve transported them to CHESS on the evening of 10/13, and they were stored in the cold room overnight. Mike P, John I, and Tricia C aligned the station.

Steve adjusted the mirror and the s3h calibration, and recovered a lot of flux (up ~1.6x from 3.9 x 10¹⁰ ph/s on 2026-09-30):

From id7b2.classe.cornell.edu
Wed Oct 14 15:21:43 2026

Output of macro ct

Wed Oct 14 15:21:44 2026

     Seconds = 1
       Diode = 36 (36/s)
          I2 = 72925 (72925/s)
        ICol = 270685 (270685/s)
        Gate = 0 (0/s)
       QuadX = 0 (0/s)
       QuadY = 0.000132 (0.000132/s)
       newI1 = 152599 (152599/s)
       newI0 = 234765 (234765/s)

Samples

Name	Sample	Well composition	Drop composition	Notes
DHFR-Folate-NADP	E. coli dihydrofolate reductase with folate and NADP+			Looped by Neti B on 10/13 and stored in the cold room at CHESS overnight.

Data collection

Collected a 1 s exposure with nothing in the beam to document the background scatter. Slits 100 x 100 µm.

Subdirectory: setup

prefix	φ0 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
air_1751	0	0.1	1	1	100	185	14
air_1752	0	0.1	1	1	100	185	14

1. DHFR-Folate-NADP (dose test)

Starting the DHFR samples with crystal #25 (the plan was to go in reverse order). No screenshot was recorded.

Regular (not vector) scans, 360˚. Slits 100 x 100 µm. Temperature 300 K (per xia2 metadata).

Subdirectory: DHFR/DHFR_25

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_25_300K_1753*	0	360	0.1	3600	0.01	100	185	14
DHFR_25_300K_1754	0	360	0.1	3600	0.01	100	185	14

first scan at the tip of the crystal

* DHFR_25_300K_1753 was collected at the tip of the crystal. The crystal was then moved to a new spot for DHFR_25_300K_1754. Only 1754 was processed.

no background

No background scan was collected for this crystal.

B-factor decayed by ~4 Å² over the 36 s data collection. So the lifetime (without vector, at 100% transmission) is approximately 18 s. Our strategy will be to collect 180˚ from each crystal and vector over a ~500 µm distance if possible, maintaining 100% transmission.

xia2 processing

	DHFR_25_300K_1754
scan	1754
Mosaic spread	0.105
Resolution	1.22
Unit Cell	[34.42, 45.71, 99.09, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	100.0
Multiplicity	12.6
I/sigma	10.0
Rpim	0.026
Wilson B factor	14.44
Space group	P 21 21 21
temperature	300

2. DHFR-Folate-NADP (multi-T)

Crystal #4. No screenshot was recorded.

Vector scan (spinx translation: 419.2 µm). Slits 100 x 100 µm.

Plan: 295, 310, 295, 280, 295 K temperature series, with 5 minute wait time after each temperature change. (A 320 K step and a final 295 K step were added at the end.)

Subdirectory: DHFR/DHFR_4

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_295K_1755	0	180	0.1	1800	0.01	100	185	14
DHFR_4_295K_bg_1756	0	180	1	180	0.1	100	185	14

Ramped to 310 K and waited 5 min.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_310K_1757	0	180	0.1	1800	0.01	100	185	14
DHFR_4_310K_bg_1758	0	180	1	180	0.1	100	185	14

Changed temperature to 295 K, waited 5 min.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_295K_1759	0	180	0.1	1800	0.01	100	185	14
DHFR_4_295K_bg_1760	0	180	1	180	0.1	100	185	14

Changed temperature to 280 K, waited 5 min.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_280K_1761	0	180	0.1	1800	0.01	100	185	14
DHFR_4_280K_bg_1762	0	180	1	180	0.1	100	185	14

Changed temperature to 295 K, waited 5 min.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_295K_1763	0	180	0.1	1800	0.01	100	185	14
DHFR_4_295K_bg_1764	0	180	1	180	0.1	100	185	14

Changed temperature to 320 K, waited 5 min.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_320K_1765	0	180	0.1	1800	0.01	100	185	14
DHFR_4_320K_bg_1766	0	180	1	180	0.1	100	185	14

Changed temperature to 295 K.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_4_295K_1767	0	180	0.1	1800	0.01	100	185	14
DHFR_4_295K_bg_1768	0	180	1	180	0.1	100	185	14

condensation

Condensation drops were observed on the plastic capillary after the 320 K step. DHFR_4_320K_1765 and DHFR_4_295K_1767 may be affected.

xia2 processing

	DHFR_4_295K_1755	DHFR_4_310K_1757	DHFR_4_295K_1759	DHFR_4_280K_1761	DHFR_4_295K_1763	DHFR_4_320K_1765
scan	1755	1757	1759	1761	1763	1765
Mosaic spread	0.022	0.022	0.021	0.024	0.023	0.024
Resolution	1.16	1.16	1.19	1.21	1.22	1.21
Unit Cell	[34.45, 45.79, 98.95, 90.0, 90.0, 90.0]	[34.45, 45.79, 98.96, 90.0, 90.0, 90.0]	[34.45, 45.77, 98.99, 90.0, 90.0, 90.0]	[34.42, 45.67, 99.02, 90.0, 90.0, 90.0]	[34.42, 45.69, 99.06, 90.0, 90.0, 90.0]	[34.45, 45.78, 99.02, 90.0, 90.0, 90.0]
Image range	[1, 1800]	[1, 1800]	[1, 1800]	[1, 1800]	[1, 1800]	[1, 1800]
Completeness	95.0	95.0	96.6	96.9	97.0	96.9
Multiplicity	6.3	6.3	6.4	6.5	6.5	6.5
I/sigma	7.7	7.6	5.7	8.2	7.8	8.5
Rpim	0.048	0.048	0.06	0.046	0.048	0.042
Wilson B factor	13.93	14.01	13.99	14.34	14.69	14.79
Space group	P 21 21 21	P 21 21 21	P 21 21 21	P 21 21 21	P 21 21 21	P 21 21 21
temperature	295	310	295	280	295	320

3. DHFR-Folate-NADP (multi-T)

DHFR_3

Crystal #3. Might be 2 crystals (the screenshot shows a second rod sticking out below the main crystal). Mounted the crystal and waited 5 min. Checked for condensation; none after this.

Vector scan (spinx translation: 172.8 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_3

Took a screenshot of the crystal.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_3_295K_1769	0	180	0.1	1800	0.01	100	185	14
DHFR_3_295K_bg_1770	0	180	1	180	0.1	100	185	14

xia2: unit cell [34.3, 45.4, 99.2, 90, 90, 90], 1.24 Å.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_3_310K_1771	0	180	0.1	1800	0.01	100	185	14
DHFR_3_310K_bg_1772	0	180	1	180	0.1	100	185	14

poor diffraction at 310 K

The diffraction at 310 K (DHFR_3_310K_1771) looked bad, so we moved on. Only the 295 K scan was processed. The crystal may also contain a second lattice (see screenshot).

xia2 processing

	DHFR_3_295K_1769
scan	1769
Mosaic spread	0.05
Resolution	1.24
Unit Cell	[34.32, 45.37, 99.24, 90.0, 90.0, 90.0]
Image range	[1, 1800]
Completeness	100.0
Multiplicity	6.4
I/sigma	12.0
Rpim	0.034
Wilson B factor	15.76
Space group	P 21 21 21
temperature	295

4. DHFR-Folate-NADP

DHFR_2

Crystal #2. Took a photo (DHFR-2.PNG in the notebook; DHFR_2.png here). The cryostream was coming down from 310 K to 295 K.

Vector scan (spinx translation: 374.3 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_2

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_2_295K_1773*	180	0.1	1800	0.01	100	185	14
DHFR_2_295K_1774	180	0.1	1800	0.01	100	185	14
DHFR_2_295K_bg_1775	180	1	180	0.1	100	185	14

repeated scan

* DHFR_2_295K_1773 was repeated as DHFR_2_295K_1774 42 s later (the notebook scan number was corrected from 1773 to 1774). Use 1774.

poor statistics

xia2: mosaicity 0.32˚ and resolution 1.67 Å, much worse than the other DHFR crystals measured today (first 295 K scan: mosaicity 0.02–0.08˚, resolution 1.16–1.24 Å). Rpim 0.094.

A 310 K scan (DHFR_2_310K) was planned but crossed out in the notebook and not collected.

xia2 processing

	DHFR_2_295K_1774
scan	1774
Mosaic spread	0.321
Resolution	1.67
Unit Cell	[34.27, 45.17, 99.2, 90.0, 90.0, 90.0]
Image range	[1, 1800]
Completeness	99.4
Multiplicity	6.6
I/sigma	8.2
Rpim	0.094
Wilson B factor	18.54
Space group	P 21 21 21
temperature	295

5. DHFR-Folate-NADP

DHFR_1

Crystal #1. Took a photo.

Vector scan (spinx translation: 350.4 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_1

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_1_295K_1776	0	180	0.1	1800	0.01	100	185	14
DHFR_1_295K_bg_1777	0	180	1	180	0.1	100	185	14

Great crystal. xia2: [34.30, 45.17, 99.25], mosaicity 0.079˚. There is some radiation damage?

Changed temperature to 310 K. No condensation yet. There are a few drops on the capillary, but probably not condensation.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_1_310K_1778	0	180	0.1	1800	0.01	100	185	14
DHFR_1_310K_bg_1779	0	180	1	180	0.1	100	185	14

very mosaic at 310 K

The diffraction at 310 K looked very mosaic, so we moved on to another crystal. xia2: mosaicity 0.86˚ (vs 0.079˚ at 295 K), resolution 1.76 Å (vs 1.17 Å), Wilson B 26.1 Å² (vs 14.7 Å²), and the unit cell shrank (a, b = 34.07, 44.73 Å vs 34.28, 45.19 Å).

xia2 processing

	DHFR_1_295K_1776	DHFR_1_310K_1778
scan	1776	1778
Mosaic spread	0.079	0.863
Resolution	1.17	1.76
Unit Cell	[34.28, 45.19, 99.21, 90.0, 90.0, 90.0]	[34.07, 44.73, 99.02, 90.0, 90.0, 90.0]
Image range	[1, 1800]	[1, 1800]
Completeness	95.6	98.3
Multiplicity	6.3	6.6
I/sigma	13.3	8.3
Rpim	0.024	0.059
Wilson B factor	14.71	26.13
Space group	P 21 21 21	P 21 21 21
temperature	295	310

6. DHFR-Folate-NADP (multi-T)

DHFR_5

Crystal #5. Took a photo: it is a thin crystal.

Vector scan (spinx translation: 443.1 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_5

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_5_295k_1780	0	180	0.1	1800	0.01	100	185	14
DHFR_5_295k_bg_1781	0	180	1	180	0.1	100	185	14

xia2: [34.4, 45.6, 99.1], mosaicity 0.02˚.

Cooled to 280 K.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_5_280k_1782	0	180	0.1	1800	0.01	100	185	14
DHFR_5_280k_bg_1783	0	180	1	180	0.1	100	185	14

Good scattering. xia2: [34.4, 45.5, 99.14].

Heated back to 295 K. No condensation yet.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_5_295K_1784	0	180	0.1	1800	0.01	100	185	14
DHFR_5_295K_bg_1785	0	180	1	180	0.1	100	185	14

Good scattering. Heated to 310 K. No condensation yet.

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_5_310K_1786	0	180	0.1	1800	0.01	100	185	14
DHFR_5_310K_bg_1787	0	180	1	180	0.1	100	185	14

Good scattering. Going down to 295 K. Condensation seen (not too much, though).

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_5_295K_1788	0	180	0.1	1800	0.01	100	185	14
DHFR_5_295K_bg_1789	0	180	1	180	0.1	100	185	14

Good scattering.

file naming

The first two temperature steps use a lowercase "k" in the prefix (DHFR_5_295k_1780, DHFR_5_280k_1782 and their backgrounds), unlike all other scans (..._295K_...).

high Rpim

Although the diffraction looked good, xia2 reports Rpim 0.17–0.27 for this crystal, several times higher than the other DHFR crystals measured today (0.024–0.06, excluding DHFR_2 at 0.094). Resolution also degrades across the series at 295 K: 1.23 Å (1780) → 1.72 Å (1784).

condensation

Some condensation was observed after the 310 K step, before DHFR_5_295K_1788.

xia2 processing

	DHFR_5_295k_1780	DHFR_5_280k_1782	DHFR_5_295K_1784
scan	1780	1782	1784
Mosaic spread	0.019	0.021	0.03
Resolution	1.23	1.4	1.72
Unit Cell	[34.43, 45.63, 99.05, 90.0, 90.0, 90.0]	[34.4, 45.52, 99.13, 90.0, 90.0, 90.0]	[34.42, 45.63, 99.14, 90.0, 90.0, 90.0]
Image range	[1, 1800]	[1, 1800]	[1, 1800]
Completeness	99.8	100.0	100.0
Multiplicity	5.6	6.0	6.0
I/sigma	7.3	12.7	22.1
Rpim	0.172	0.269	0.189
Wilson B factor	15.47	15.05	16.38
Space group	P 21 21 21	P 21 21 21	P 21 21 21
temperature	295	280	295

7. DHFR-Folate-NADP

DHFR_6

Crystal #6. Collected at 280 K.

Vector scan (spinx translation: 161.6 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_6

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_6_280K_1790	0	180	0.1	1800	0.01	100	185	14
DHFR_6_280K_1791	0	180	0.1	1800	0.01	100	185	14

poor diffraction

Really bad diffraction. No background scan was collected, and no xia2 results are available.

8. DHFR-Folate-NADP

DHFR_7

Crystal #7. Collected at 280 K, 360˚.

Vector scan (spinx translation: 272.1 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_7

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_7_280K_1792	0	360	0.1	3600	0.01	100	185	14
DHFR_7_280K_bg_1793	0	360	1	360	0.1	100	185	14

xia2 processing

	DHFR_7_280K_1792
scan	1792
Mosaic spread	0.08
Resolution	1.27
Unit Cell	[34.36, 45.21, 99.38, 90.0, 90.0, 90.0]
Image range	[1, 3600]
Completeness	98.0
Multiplicity	13.2
I/sigma	11.2
Rpim	0.025
Wilson B factor	16.46
Space group	P 21 21 21
temperature	280

9. DHFR-Folate-NADP

Crystal #8. Collected at 280 K, 360˚. No screenshot was recorded.

Vector scan (spinx translation: 350.4 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_8

prefix	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_8_280K_1794	360	0.1	3600	0.01	100	185	14
DHFR_8_280K_bg_1795	360	1	360	0.1	100	185	14
DHFR_8_280K_bg_1796	360	1	360	0.1	100	185	14

temperature uncertain

The temperature was off: the cryostream was not at 280 K during this crystal, despite the 280K prefix. The actual temperature is unknown.

two background scans

Two background scans were collected. The notebook marks DHFR_8_280K_bg_1796 as the correct background.

10. DHFR-Folate-NADP

Crystal #11. Collected at 280 K, 360˚. No screenshot was recorded.

Vector scan (spinx translation: 395.2 µm). Slits 100 x 100 µm.

Subdirectory: DHFR/DHFR_11

prefix	φ0 (deg.)	φ1 (deg.)	∆φ (deg.)	images	∆t (s)	tf (%)	d (mm)	E (keV)
DHFR_11_280K_1797	0	360	0.1	3600	0.01	100	185	14

no background; temperature uncertain

No background scan was collected. The cryostream controller faulted several times around this time, so the temperature may not have been 280 K.

The cryostream controller faulted several times. Called it a night after DHFR_11 (last scan at 23:27).

Done!

2026-10-14 @ CHESS 7b2

Goals

Participants

Data

Beamline setup

Samples

Data collection

1. DHFR-Folate-NADP (dose test)

2. DHFR-Folate-NADP (multi-T)

3. DHFR-Folate-NADP (multi-T)

4. DHFR-Folate-NADP

5. DHFR-Folate-NADP

6. DHFR-Folate-NADP (multi-T)

7. DHFR-Folate-NADP

8. DHFR-Folate-NADP

9. DHFR-Folate-NADP

10. DHFR-Folate-NADP

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